Class Book FTqq i .GrZIo GopyrigMN 0 _ COPYRIGHT DEPOSIT. GPO / A COMPLETE TREATISE ON THE MANUFACTURE OF SOAP. / WITH SPECIAL REFERENCE TO i AMERICAN CONDITIONS AND PRACTICE. BY u/ DR. HENRY GATHMANN, 'I Editor of the American Soap Journal. 3 > j’o -)- 3 » 3 * SECOND EDITION. CONTAINING Many Practical Additions and Suggestions by a number of successful and well-known Soap Manufacturers, and illustrated by 101 engravings. NEW YORK, U. S. A. v Dr. Henry Gathmann, 9 E. 42d Street. 1899. L - N TWO COPIES RECEIVED, Library of Congrsas, Office o f the Dtii 6- IRoq ■ S» »# •/ Register of Copyrights, 5:i?44 Copyright by HENRY GATHMANN 1899 MCOND COPY, \^o4- -VX .Woe I Preface to the Second Edition. ROM the time when the first edition of American Soaps ap- 1 peared in print, seven years ago, the author has continually collected all available new information that could assist in making a later edition of the book more complete and that could serve to keep it abreast of the times. Much assistance in this respect has been gained indirectly from requests for special information made in the interval by purchasers of the original edition, questions which have served to show in what directions the book could be completed by greater details or brought up to date by newer in¬ formation. Besides this, many voluntary contributions and pract¬ ical hints have been received during the same time from numerous friends, for the express purpose of having them embodied in the new edition so long in preparation. As the result of these several additions, every chapter of the original work has been carefully revised, completed and brought up to date, embodying changes which in some chapters amount to practically an entirely new treatment of the subject. Apart from these substantial additions and changes made in every part of the work, there are three entirely new chapters on subjects of importance which have been added on the suggestion of friends some of whom had placed their order in advance for a copy of any new edition that might appear. The plan underlying the original edition of this work, namely to print only matter of practical importance, excluding all obsolete processes, theoretical methods, intricate chemistry, etc., has met with such favor among the practical manufacturers of soap in all countries, that it has been scrupulously adhered to in the present edition as well; the new items and changes consist of practical points almost exclusively. In respect to the (new) chapter on simple tests to be made in the soap factory, for the purpose of examining raw materials and 4 Prfface. products, the same plan has been followed; that is to say, on the ground that those equipped for elaborate tests are also provided with the latest literature on that subject, no attempt has been made to describe difficult chemical tests requiring expert skill to make them ; instead of that there are collected in this chapter tests that can be made with little difficulty by every soapmaker, with results at least valuable, if not always so absolutely correct as can in certain cases be obtained by one experienced in difficult chemi¬ cal work and equipped with a large laboratory. In short, this revised edition has been prepared with a view to preserve American Soaps the distinction it has already gained ; that of being the standard text book on the art of soapmaking as actually practiced in American factories. In conclusion, as it was a pleasant duty to acknowledge be¬ fore my indebtedness for numerous valuable hints and sugges¬ tions, to such practical manufacturers as Messrs. Geo. A. Schmidt, Melzer Bros., F. B. Strunz and others, so I have again to thank numerous friends, who have, by their recent communications and advice, assisted materially in bringing together the new ma¬ terial now added to this work, most of which now appears in print for the first time. New York, November, 1899. tfl vV IV'l/y INDEX OF CONTENTS. Introduction Page. .. 11 ) CHAPTER I. The Nature of Soap. Alkalies in general.1. 23 Fats and fatty acids in general. 24 Soap, its formation, various ingredients, &c. 25 CHAPTER II. Fats and Oil's. Fats and oils, their effect on soap, &c. Rancidity. Adulteration of fats and oils, preliminary tests for same Rendering (2 illustrations). Tallow and bleaching same. Grease and bleaching same. Lard. Cocoanut oil and bleaching same ; copra oil. Palm oil and bleaching same (1 illustration). Palm kernel oil. Olive oil and foots ; bleaching foots. Cottonseed oil ; bleaching. Cottonseed stearin. Cottonseed foots ; soap stock ; bleaching. Linseed oil and bleaching same.. Castor oil. Wool grease ; lanolin. Various other oils and fats. Oleic acid (red oil). Rosin. 31 3r, 35 38 42 45 47 48 51 55 56 57 60 60 62 63 63 64 66 68 6 Index. CHAPTER III. Lye scale (1 illustration). 71 Grades of alkali. 72 Quality of Lyes. 73 Effect of lyes of different quality, in different stock and processes. 74 Pure caustic ; carbonate of soda. 76 Salt. 76 Potash... 77 Effect of lyes of different strengths. 78 CHAPTER IV. Filling Materials. Talc. 79 Silex. 80 Silicate of soda and of potash. 80 Starch. 81 Mineral soap stock. 82 Soda ash, sal soda, sulphate of soda, salt, potash, borax, &c. 82 Various other materials used in soap making. 83 CHAPTER V. The Soap Factory. Location. 87 Arrangement. 87 The building. 88 The lye tank (6 illustrations). 89 Strunz patent lye apparatus (2 illustrations). 95 Melting trough (1 illustration). 98 Settling tank. 99 Stock blower (1 illustration). 100 Soap kettles (10 illustrations). 101 Connections with kettles. Ill Soap pumps (9 illustrations). 112 Crutchers and re-melters (11 illustrations). 116 Sal soda tank. 127 Soap frames (7 illustrations). 127 Trucks (1 illustration). 132 Slabbers and cutters (9 illustrations). 134 Drying apparatus (2 illustrations). 141 Presses (11 illustrations). 142 Dies (18 illustrations), including safety devices. 149 Chipper (2 illustrations). 164 Mill (3 illustrations).•. 165 Plodder (3 illustrations). 166 Powder mills (1 illustration).'. 169 Steam separator (1 illustration). 170 Index. 7 CHAPTER VI. Manufacture of Soaps. Page. Selection of materials and methods for certain soaps. 173 Form and quality of soaps. 178 Special properties of the soap to be made. 179 Selection of process (cold, half-boiled, boiled, milled). 180 Re-melted soap. 188 CHAPTER VII. Settled Soaps. Rosin soap. 185 Saponification of the fat. 186 Graining. 190 Rosin Change. 192 Strengthening change. y . 194 Finishing. 195 General remarks. 196 Framing and filling. 197 Stripping, cuttiug, drying, &c. 201 The nigre and its uses. 202 Scraps. 204 White settled soap. 205 CHAPTER VIII. Boiled-Down Soaps. German mottled. 212 White boiled-down soap. 220 CHAPTER IX. Eschweger Soap. Eschweger soap. 223 Blue mottled. 229 Modified process. 232 CHAPTER X. Soft (Potasii) Soap. General remarks. 235 Stock and lye. 237 Filling. 238 Rosin ... 240 The boiling. 243 Crown soaps. 243 Figged soaps. 245 Artificially figged soap. 247 Index. 8 CHAPTER XI. General Remarks. Page. General remarks on boiling soaps. . 241) CHAPTER XII. Half-Boiled Soaps. Introduetion and description of process, filling, &e. 257 Advantages and disadvantages of lialf-boiling. 259 Half-boiled white soap. 261 “ for milling. 262 << u mottled. 2613 “ “ floating soap. 264 “ rosin soap. 264 “ '« tar soap. 265 “ “ filled soap. 266 “ “ cocoanut oil soap. 266 “ “ transparent (see special chapter). CHAPTER XIII. Cold-Made Soap. Advantages and disadvantages of cold process. 269 Selection of stock for cold-made soaps. 271 Purity of the stock. 273 Quality of the lye. 275 Quantity and strength of lye.:. 277 Temperature of stock for mixing. 279 Mixing and saponification.;... 281 Filling. 283 Perfuming, coloring, marbling. 284 Formulas for various cold-made soaps. 286 Pure cocoanut oil soap. 286 Filled cocoanut oil soap.. 287 Cocoanut oil soap, filled with salt solution. 287 Tallow and cocoanut oil soap. 287 Glycerin soap. 290 Lanolin soap. 291 Laundry soaps. 291 Rosin soaps. 292 Tar soap. 293 Carbolic soap. 294 Utilizing scraps of cold soaps. 294 CHAPTER XIV. 299 Re-Melting Soap CHAPTER XV. Milled Soaps. Page. General remarks. 303 Stock for milled soaps. 305 The milling process.... 307 Perfuming milled soaps. 310 tr 1 • CHAPTER XVI. Coloring and Perfuming. Coloring.,. 313 Perfuming. 319 Selection and preparation of the perfumes. 337 Perfumes for laundry soaps. 340 “ “ cold-made soaps... 341 “ “ (boiled) milled toilet soaps. 345 CHAPTER XVII. Pressing the Soap . 350 / CHAPTER XVIII. Special Soaps. Floating soap. 357 Transparent soap.'•. 359 General remarks. 359 Shaving soap.. 367 Perfuming. 370 Tooth soap. 370 Scouring soap. 372 Metal polishing soap.-. 374 Harness soap. 374 Carbolic soap.’. 375 Red mottled castile...*. 375 Saltwater soap. 376 Tar soap. 376 Gall soap. 377 Medicinal soap. 378 Sulphur soap. 383 Surgical soap. 384 Washing powder. 385 CHAPTER XIX. Page. Sal Soda Making. 389 CHAPTER XX. Glycerin and its Recovery from Waste Lye. Recovery from waste lye. 397 / I CHAPTER XXI. The Simpler Tests and Examinations in the Soap Factory. Alcohol. 413 Borax . 414 Essential oils. 415 Fats and oils. 419 Glycerin. 422 Soaps. 424 Soda and potash. 427 Tar. 432 Tables etc. 437 The thermometer.. 439 Table showing centigrade degrees and their equivalent on Fahrenheit scale. 440 Appendix. 443 Index. 451 PART I. A * - * . . . I A Few Words to the Practical Soapmakers. Among - the contents of this book the practical soapmaker will recognize many statements of facts which, through his own practical experience and observation, and through his previous study of the subject, have become perfectly familiar to him ere this. If they appear here, it is of course not with a claim for novelty, but for the sake of completeness, and for the benefit of those less well informed. If he read the book attentively, and from the beginning to the end, he will undoubtedly be amply repaid for his trouble by finding in it also many useful suggestions which are new to him, and whose value he will readily admit without question. It being in the nature of the case that such suggestions must be distributed over many different pages and chapters, the soap- maker should not fail to read all of the book, including also such chapters as may treat of soaps which he does not make, especially so since there has been absolutely no useless padding added to unnecessarily swell the number of pages. The principal object, however, of especially addressing the practical soapmakers in these few lines, is to remind them of the fact that the time has not come yet when even the most expert will agree on all the practical points involved in their art, even under the same conditions otherwise, and that circumstances vary on every hand. It is therefore fully expected that the ex¬ perienced soapmaker will find in the practical part of this book more or less that he will see proper to disagree with. It is his privilege to criticize this work, but he should not do so until he has carefully read the whole book, nor without considering that this treatise is based on the actual experience of many of the most expert in the art; those practical soapmakers, therefore, will not be doing justice to their own best interests who refuse 18 A Few Words to the Practical Soapmakers. to at least give the most serious thought to all those points ex¬ pressed that happen not to be in accord with the opinions they have held up to the present. In regard to the figures named here and there as to strength, quantity or time, every soapmaker knows from experience that there is hardly an operation carried out in the factory which is not subject to changes under varying circumstances ; the arrange¬ ment of the kettles and of the other machinery, changes in the purity of the raw materials, climate and local conditions, as well as the greater or less degree of care and time that can be devoted to the quality of the product, and the state of the market—all these have more or less bearing on the special figures to be in¬ serted into the several formulas. It is therefore insisted above all that in the elucidation of principles, as much as in the formu¬ las, lies the value of this work, if the author may make bold at all to presume that it has any. Introduction. Although the art of soap making reaches so far back into antiquity that its early beginnings are now merely matters of conjecture, it is only in the last hundred years that the principle features of the art, as it is conducted at the present day, were developed. Leblanc’s diseov* It is now just a century ago (1791) that Leblanc, a French' ery of artificial soda. chemist, discovered and patented a process of manufacturing soda from common salt, and this invention, more than any other influence, brought about great changes in the manner in which :his industty has since been conducted. Previous to the manufacture of this artificial soda, the alka¬ lies employed by the soapmaker were derived mostly from the ashes of various plants. Special forms of such crude alkalies much used formerly (and still employed to a limited extent at the places of their production) are barilla and kelp. The former is a crude soda derived from burning plants that grow along the shores of the Mediterranean ; the latter is a similar material made in more northern countries by burning several varieties of seaweeds. Ashes from plants growing in places more distant from the sea contain mostly potash, instead of soda. Leblanc, whose invention has been of incalculable benefit to mankind, died in the greatest poverty in the year 1806. Fifty years later (1841) another great discovery, and one of chevreui’sdiseov considerable influence in the soap industry also, was made by Chevreul—like Leblanc, a celebrated French chemist—who at that time discovered the true composition of fats, and who was first to explain correctly the nature of the chemical action by which soap is formed from fat and alkalies. His discovery has been of the greatest practical value to the fat industry, and all the allied branches Chevreul died only a few years ago (1889) 20 Introduction. at the remarkable age of 102 years, and, unlike the unfortunate Leblanc, had the satisfaction of at least reaping a substantial reward for his numerous useful labors. To the achievements of these two men, therefore, is due in a great measure, directly and indirectly, the enormous develop¬ ment of the soap industry at present. It is true that other pro¬ cesses for the artificial manufacture of soda have since been discovered and come into use, besides the Leblanc process, but this was at a time when the Leblanc alkali had already modified the manufacture of soap to a very great extent. Considering then the comparatively recent date of these two far-reaching discoveries, it is not. surprising that—particularly in the United States—the manufacture of soap should have un¬ dergone great changes in the last fifty years, especially as it is only since 1839 that cocoanut oil came into use for soap making, while cotton seed oil was not introduced until about fifteen years later. Fifty years ago the American methods still greatly re¬ sembled those employed in England, but since that time they have become materially changed. The New England States were then the principal center of the American soap industry, and the soaps made from the raw materials and with the appli¬ ances available were in many respects very different from those of the present time. Filling materials were practically unknown, and the “settled ” soap was simply run into the wooden (lift ) frames and crutched for hours until it became thick from cooling ; or it was finished by boiling down, or perhaps by “running.” The soap was ladeled by hand from the kettles into the frames, or into buckets or tubs, which were then carried to where the frames were placed, to le emptied into the latter. The soap kettles were made of cast iron bottoms, to which a wooden curb was fastened by means of wedges and cement, and the composi¬ tion of a cement that would prevent leakage for any length of time was then considered a great trade secret! Through the wooden curb just mentioned a pipe entered, which reached down to near the bottom of the kettle and by means of which the waste lye was run off. The kettles were heated by open fire and the contents were stirred and kept from burning or adhering to the bottom by means of a long iron rod, flattened at the end. The lye was made either by causticizing soda ash with lime or by leaching wood ashes, for caustic soda did not become a commercial article until the beginning of the present century, Introduction. 21 and was but slowly adopted for use in soap factories at first. The first pressed cakes of laundry soap are said to have been brought on the market by B. T. Babbitt, of New York. At that time the soapmakers also were much more generally man¬ ufacturing candles, lard oil, potash and soft soap than they are now. When the civil war broke out rosin became very scarce, and was, therefore, largely substituted by simply adding water to the soap ; silicate of soda was used similarly in some cases, but its use had not yet become general at that time. Most forms of adulterations of soap have become known only within the last half century. After the war, when rosin was again more plentiful, there M proveraents ^ was a tendency at first to return to the old methods of making unfilled settled soap, but soon after (some time in the sixties) the process of hardening resin soaps by means of sal soda was first introduced; its first application is ascribed to A. Van Haagen, then of Philadelphia. Gradually the process of recovering glycerin from waste soap lye had been perfected in England, and began to be prac¬ ticed and improved upon in our large soap factories here, until now a crude glycerin is furnished to refiners by quite a number of soap factories, operating by various methods, while there is also a constantly growing list of soap factories in which the crude glycerin is worked up into the refined article. The early beginnings of soap powder manufacturers also fall into this period, and at the present date have developed into a by no means inconsiderable industry. About twenty years ago white floating soap was first brought on the market by Proctor & Gamble, Cincinnati, Ohio. Naturally, during these fifty years a great number of im¬ provements in the equipment of factories were also made, and a large number of patents were secured on machinery and pro¬ cesses relating to soap making. Few, if any, of the patented processes, however, have proved useful. At present the best grades of soap made in America are at least equal to those made anywhere in the world, while in regard to mechanical facilities for operating on large quantities, with the greatest economy of time and labor, this country is acknow¬ ledged to take the lead. CHAPTER I. The Nature of Soap. The soaps of commerce being- essentially products of fats and alkali, a few preliminary remarks about these ingredients will not be out of place before considering the nature of soap itself. ALKALIES. The term ‘‘alkalies” is employed to designate a certain small group of chemicals which are characterized principally by the following properties : They are caustic (that is to say, cor¬ rosive, destructive, on animal tissues), soluble in water, combine readily with acids—whose properties they neutralize in so doing —and turn certain vegetable yellow colors into red. The alkalies, ni the order of their importance to the soapmaker, are Soda, Pot¬ ash, and Ammonia. (To this group also belongs Lithia, which, however, is of no special interest to the soapmaker). When an acid of any kind is subjected to the action of an alkali, there is formed a new compound—chemically called a “salt”—which will be neutral, /. e ., neither acid nor alkaline in its effect on animal tissues or on vegetable colors. (See Appendix, Note 1.) Soap is, chemically speaking, such a salt. The alkalies may be either “carbonated” or “caustic.” Car¬ bonated soda, for instance, is soda combined with carbonic acid, as in the case of ordinary washing soda, or soda crystals. When the carbonic acid is withdrawn from the latter by any suitable means, such as quicklime, the previously “carbonated” soda be¬ comes “caustic” soda. Alkaline Earths: Lime and Magnesia are similar to, but not true alkalies; they belong to a class of chemicals to which has been given the name of “alkaline earths,” because their proper¬ ties are partly identical with those of the true alkalies, while on Alkalies defined. Carbonated and caustic alkalies Alkaline earths, 24 The Nature of Soap. Composition of Fats and Oils. the other hand they range themselves with the true earths. Their compounds with fatty acids are soaps in a certain sense, but being insoluble in water, cannot be used for the purposes of the ordinary soda or potash soaps. (See Appendix, Note 1.) FATS AND FATTY ACIDS. The numerous fats and fatty oils of animal as well as veget¬ able origin, such as tallow, bone grease, lard, train oil, palm oil, cotton seed oil, cocoanut oil, etc.., etc., are neutral substances, which may be decomposed by the aid of a current of superheated steam, or by other suitable means, into two distinctly separate portions : a mixture of so-called “fatty acids” or “ sebacic acids ” on one hand, and the familiar substance of “glycerin” on the other. When a fat has been so decomposed into its constituent parts, the fatty acids in their uncombined state exert a distinctly acid effect on other substances, as may be witnessed, for instance, in the corrosion of metals by lubricating greases containing free fatty acids. The fats are insoluble in water, melt and burn readily, and cause permanent grease stains if applied to paper ; they combine with alkalies, alkaline earths, etc., to form various compounds. Glycerin is a neutral substance, formed by the combination of water with the “glyceryl” contained in neutral fats. Each fat, as is found in nature, contains several different fatty acids, (combined with glycerin), the principal ones of which are named respectively stearic, palmitic and oleic acid. Tallow, for instance, may be separated by pressure, suitably ap¬ plied, into a liquid and a solid portion, the former being prin¬ cipally olein (oleic acid combined with glycerin) and the latter a mixture of palmitin and stearin (palmitic and stearic acid, combined with glycerin.) Oleic acid is liquid at ordinary tem¬ peratures, congealing only when cooled to about 40 c F. Eauric, palmitic and stearic acids are solid, melting at about 110°, 144°, and 156 : F., respectively. According as the most solid fatty acids are present in larger proportions the different fats them¬ selves will be more solid. The fatty acids of any fat desired may be most easily pro¬ cured for examination by dissolving some soap, made of such fat, in water, and adding a little sulphuric acid, whereby the fatty acids are displaced from their combination with the alkali and rise—mixed with each other in proportions according to the The Nature of Soap. 25 nature of the fat from which the soap was made—to the surface of the solution. (See Appendix, Notes 2 and 3.) The “mineral” and the “essential” oils are entirely differ¬ ent substances in composition from the fatty oils; they have hardly anything- in common with the latter (except their oily ap¬ pearance and ready inflammability), containing* neither fatty acids nor g^cerin, and are incapable of forming- soaps. SOAPS. ’ The Formation of Soap : As has been said in the foregoing, a neutral compound is the result when an acid and a base, such as an alkali, are caused to chemically react upon each other. This is true in the case of the fatty acids as well as in that of the stronger mineral acids—such as sulphuric and nitric acids— and when a quantity of an}^ fatty acid is boiled together with an equivalent amount of a solution of caustic alkali in water (lye), the product will be the neutral compound “Soap.” It is not, however, necessar} T , or even desirable, to decompose the fat into free fatty acids and glyceryl (or glycerin)' before boiling with lye, in order to make soap, for acids naturally have a stronger affinity for alkali than for glyceryl, and consequently when a neutral fat is boiled with a caustic lye, the fatty acids thereof combine with the alkali, separating from the glyceryl-which in turn combines with some of the water of the lye and is, at the end of the operation, found in the kettle as glycerin (which is uncombined with the soap and simply mechanically mixed with the mass); in boiled soaps the gljxerin is generally separ" ated, together with the waste lye in which it is dissolved, in the next stage of the manufacture. To recapitulate the essential parts of the foregoing, then, in one short statement, compare the following two lines : Fats are neutral salts of fatty acids with glyceryl as a base. Soaps “ “ “ “ “ “ alkali “ “ The process of soapmaking is, therefore, essentially a substitu¬ tion of one base (alkali) for another (glyceryl.) In combining to form soap, as described, the fatty acids as well as the alkali lose their identity, so to speak, for the soap is not corrosive as was the alkali, nor is it greasy and insoluble in water, as were the fatty acids; from this it is evident that soap is not simply a mixture of alkali and fatty acids, but a true chemical compound ; in other words they are the soda (or potash) salts of stearic, Mineral and es¬ sential oils. Combination of fats and alkali. 26 The Nature of Soap. Definite p ro por¬ tions of fat and alkali reqiiii’ed. Necessity and ef¬ fect of w a t e r present in soap. palmitic, oleic, and lauric acids, mixed in varying - proportions according - to the kinds of stock used. Here now it must be re¬ membered that, while mixtures may be made in any desired pro¬ portion of one ingredient to the other, chemical compounds are formed always in absolutely fixed proportions. Thus a certain amount of fat requires a certain amount of alkali to transform it into soap ; if less alkali than required be used, a part of the fat will remain simply mixed in the soap, unsaturated by lye, and the product will be but incompletely soluble in water and of a greasy ctuiracter; if more than the required amount of lye be employed, it will—unless removed by subsequent treatment— remain in the soap as free alkali, and make the product sharp and caustic in the proportion of the excess present. When made properly, the fatty acids of the soap balance (neutralize) exactly the causticity of the lye, and the soap is neutral. The process of soap making - , therefore, consists in its principal features in bringing - fat and alkali into direct contact with each other by suit¬ able means, whereby the fatty acids combine chemically with the alkali to form soap, glycerin being - at the same time set free from the fat and either remaining - in the soap or being - re¬ moved by subsequent treatment, according - to the particular process of manufacture adopted. (See Appendix, Note 4.) The ordinary soaps of commerce are soluble in alcohol and in weak caustic lye, but insoluble in ether, benzol, petroleum ether, and in concentrated lye. Alcoholic solutions are trans¬ parent and on cooling - —if sufficiently concentrated—form a jelly, the basis of several soap liniments. If from such a solution the alcohol is expelled by evaporation the soap remains as a solid, transparent, non-crystalline mass. Solutions in hot water are clear, while those in cold water are opalescent. The Water in Soap: There is also required, for the proper formation of soap, a certain percentage of water which enables the particles of soap to form a compact and yet readily soluble mass. Other thing’s being equal, the soap is more easily solu¬ ble— and thereby more rapidly effective—in the proportion that it contains a greater percentage of water ; this proportion, of course, must be within reasonable limits in the product to be marketed, as an excessive amount would be in the nature of a deception from the purchasers’ standpoint, besides being sure, by subsequent evaporation, to render the soap unsightly and too light in weight. Freshly made soap washes quickly, but is apt The Nature of Soap. 27 to waste away in consequence of its greater solubility on which this rapid action depends. On drying* it becomes more economi cal for use, but a certain amount of water (bound in the crystals of soap) is retained under all ordinary circumstances, even if the soap has been kept for years and appears exceedingly dry. When well dried, soda-soaps become very hard and difficult to dissolve, and are then rather unsuitable for ordinary use. The amount of water contained in commercial hard soaps including that only admixed and that bound chemically, varies greatly, from say about 10 to 12 per cent, to 35 or 40 ; a greater proportion than the latter may be said to exceed the quantity really permissible for a fair commercial article. Dry soft (potash) soaps attract moisture from the atmos¬ phere. Soaps made from different fats show great variations in their affinity for water. Other Ingredients in Soap: Soap proper contains, as decribed above, fatty acids, alkali, and a moderate amount of water ; but certain other additional substances generally enter into the com¬ position of the commercial products, for various purposes—legi¬ timate and otherwise. Among these may be mentioned : Rosin, as a partial substitute for fats ; carbonate of soda, and other salts, for hardening and rendering the soap more detergent; sand, tripoli, pumice stone, and like substances, which aid mechani¬ cally in the process of cleaning; glycerin, etc., for giving the soap greater emollient properties ; sugar, alcohol and glycer¬ in, for transparency; sulphur, tar, carbolic acid, and the like, for medicated soaps ; colors and perfumes of many varieties ; silicate of soda, talc, starch, mineral soap stock, and other cheap¬ ening materials, etc., etc. (For further particulars on the “Filling” materials see Chapter IV.) The Structure of Soap : On a casual observation, soap ap¬ pears to be a perfectly homogeneous mass. But on examining it more closely it will be found that the various soaps present con¬ siderable differences in their structure, depending on the manner in which the} 7- were made. Cold-made soaps are the only ones which present a simple aggregate of microscopically small crys¬ tals, formed by the compounds of the different fatty acids with the alkali. Milled soaps have a very dense, even, grainy texture caused by the peculiar action of the machinery on the soap, which may have been made by the boiling or (more rarely) by the cold or half-boiling process. Boiled soaps, if framed hot Various ingre¬ dients of soaps 1 Thevarying struc¬ ture of soaps made by various methods. 28 The Nature of Soap. Decomposition of soap in use. Effect of h a r d water in wash¬ ing. and without filling-, will crystallize on cooling-, the stearate of soda crystallizing-out from the more slowly cong-ealing- oleate of soda, the grain formed by this process being more or less modi¬ fied by the temperature of framing, by the materials used, and by the size of the frames. If the same soaps are crutched until they are reduced to a lower temperature, these crystals will be less plainly developed, or at least will be distributed more evenly through the mass, and therefore be hardly noticeable. If filling is crutched in instead of framing the soap in its pure state, it will in most cases destroy the crystallization and cause an almost homogeneous texture. The Effect of Soap in Washing: Just in what manner the soap exerts its detersive action has been a matter of much specu¬ lation and research. The generally accepted theory regarding this subject is that, when this soap is dissolved in water, it un¬ dergoes a peculiar form of decomposition by which the neutral compound is split up into two parts—an alkaline soap and an acid soap. The alkaline soap is soluble in water and is believed to act by emulsionizing* the particles of grease contained in the articles to be cleansed, so that the dust and dirt attached to them can be easily removed ; the acid soap is almost insoluble in hot water, but more so in the soap solution, and according to this theory, contributes to the cleansing effect by the particles of dirt attaching themselves to the flakes of acid soap and thus being rinsed off with the latter. (See Appendix, Note 5.) The Water Used in Washing: The condition of the water used in washing has much to do with the action of the soap. Hard water, containing compounds of lime and of magnesia, has a peculiar effect on soap, as the sulphuric or the carbolic acid forming a part of the compounds named are capable of decom¬ posing it, combining at the same time with the alkali which it contains, and setting free the fatty acids, which then combine at once to form insoluble soaps with the lime of magnesia (see App., Note 9). In such case the lime soap (or magnesia soap) formed by the reaction here described, being insoluble in water, appears in minute flakes, which adhere to the meshes and fibres *In the presence of certain substances, as alkalies for instance, a mix¬ ture of fat and water will form an “ emulsion,” i. e., the fat is divided into microscopically small globules which float in the water, giving the mixture a milky appearance. The Nature of Soap. 29 of the cloth and produce a yellow discoloration and ultimately a disagreeable odor of the clot*hes. It is a matter of every-day observation that soft water in washing cleanses more readily and leaves the clothes whiter than when hard water is used, and when soap is used in hard water the insoluble flakes of lime or magnesia soap are readily seen. (The alkali of the soap, to¬ gether with the acid of the lime compound which causes the hardness, forms a new compound which remains dissolved in the water and is of no especial harm.) As gradually all the lime or magnesia of a hard water is so decomposed by soap, the hard¬ ness of the water decreases. So also has the free alkali in a soap a tendency to precipitate the lime (by combining with the car¬ bonic acid contained in the carbonates of lime and magnesia gen¬ erally present in hard waters), and consequently to neutralize the hardness ; it thus happens that a soap which, on account of the free alkali contained in it, is very sharp when used in soft water, may be much less so, or even quite neutral, when used in hard water ; in this case a soap containing a small excess of caustic strength is more serviceable than a neutral soap. (See App., Note 10). It has been calculated that the hardness of the water of the Thames causes an annual loss of soap in the city of Lon¬ don alone amounting to considerably over half a million dollars. The temperature of the water used for washing has as much influence on the efficiency of a soap as has its degree of hardness. The hard soap used almost exclusively in the households of this country is but imperfectly soluble in cold water, the soap formed by the combination of stearic acid and soda being soluble only in water at a higher temperature. Tallow and grease are es¬ pecially rich in stearine, and when the soaps are made of these fats the use of cold water entails a loss of soap for the reason just given; but further than that the process of emulsionizing the fatty and greasy matter to be removed by washing, as referred to above, takes place very imperfectly only when the water used for washing is cold. Hot water, therefore, it is evident, is in every way preferable. Aside from the points involved in the before mentioned theory on the action of soap, the great pene¬ trating properties of soap solution and its lubricating qualities come into play in washing, and contribute largely to the thorough effect and prompt action. Various D'etergent Substances: Besides soap, a number of substances possessing cleansing properties have been used for Effect of alkaline soap on hard water. Effect of tempera ture of water in washing. Various detergent substances. 30 The Nature of Soap. detergent purposes, and in the case of a few are sometimes in¬ corporated into soap. In the earliest times wood ashes were used for cleansing, owing to their contents of potash. It was then also discovered that the action of lime increased their efficiency (by causticizing them.) From this undoubtedly arose the invention of soap making, b} 7 combining the caustic lye with fats. In some countries the juices of a great variety of plants are utilized for cleansing purposes, the saponaceous principle being variously extracted from the roots, barks, leaves or fruits of these plants, which in a few cases form the subject of a somewhat limited commerce. Quxllaia bark from Chile, for instance, is sometimes used for washing silk; a bulb known in California as amole is sometimes employed as an ingredient for soap making, and was used for cleansing purposes by the Indians of this country before they learned the use of soap from the white man. Yucca is another plant (a native of Virginia and Carolina) which has detersive properties. Among the other substances to be mentioned in this connection are Fuller’s earth and China clay, which have the property of absorbing greasy matters ; and the alkaline substances, borax, ammonia, silicate of soda and carbonate of soda, also benzine, gasoline, ox-gall, and so forth. CHAPTER II. Fats and Oils. FATS AND OILS IN GENERAL. The oils and fats, of both vegetable and animal origin, form a class of substances which are lighter than water, practicall}" insoluble in the latter, unctuous to the touch, neutral in reac¬ tion, and cause permanent grease stains on paper; they are for the greater part very similar to each other in their chemical composition and behavior. As they are always neutral if Tin- changed, an acid reaction always points either to beginning rancidity or to some foreign (acid) substance. The pure fats and oils consist entirely of fatty acids and glj’cerin, or to be more exact, they lack only a small percentage of water in order to admit of being resolved completely into these substances. (See App. Note 14.) Thus 100 lbs. of fat may be made into about 97 lbs. of fatty acids and 8 lbs. of glycerin, a total of about 105 lbs., showing a gain of about 5 lbs., which is represented by the water required besides the fat to form these new combinations. Nearly all the fixed oils and fats are almost colorless and odorless when in a perfectly pure state, the color and odor of the crude fats and oils being due to the admixture of certain foreign color¬ ing and other matters. Leaving, for the present, out of con¬ sideration this small admixture of foreign matters, whose nature of course varies with oils of different origin, it may be said that the features distinguishing the numerous fats and oils from each other consist in the varieties and the proportions of the different fatty acids present in each fat; and by studying the peculiarities of the small number of the more important fatty acids, we learn also to better understand the reasons for the peculiarities — from the soap makers’ point of view — of the Composi t io n of fats and oils 32 Fats and Oils. different fats of which they constitute the largest portion. As said before, two or more different fatty acids, combined with gly¬ cerin, are present in every natural fat, and every fat therefore is a more or less complex body. It must be understood, moreover, that these fatty acids are not present in the fat as free acids, but they are combined with the chemical counterpart of acids i. e., a “base,” which base in this case is the “ oxide of glyceryl ’ (the body which is changed into glycerin in the process of sa¬ ponification). The acids being thus combined to the base, we have in fats neutral bodies of the class known in chemistry as “salts.” Among the fatty acids only a small number are of practical interest to the soap maker, the others being found in very small proportions only in any fat. Very important are Stearic, Oleic, and Palmitic Acid, which are present in nearly every fat used by the soapmaker, and also Laurie and Mystic Acid. (See App., Note 6.) All fatty acids combine readily with the alkalies. In their free state, as found commercially in red oil or oleic acid for in¬ stance, this combination takes place almost instantaneously, even if the lye be carbonated (that is to say, if it be made of alkali combined with carbonic acid, as distinguished from caustic alkali). The neutral fats, on the other hand, such as tallow, grease, etc., require boiling for hours with lye, which must be caustic, in order to completely saponify them. Stearic Acid and Stearin: When perfectly pure, stearic acid is devoid of odor, color, and taste, easily soluble in alcohol, but insoluble in water. Its melting point is about 150° F., at which temperature it forms a colorless, oily substance, on cooling again it forms a white, brittle, crystalline mass. It is present as stearin (stearic acid combined with oxide of glyceryl) in nearly all fats, and being of a very solid consistency, the fats contain¬ ing a considerable proportion of it, as well as the soaps made therefrom, are naturally more solid than those richer in the other varieties of the fatty acids. The hardest fats, ordinarily known as tallows, contain an especially high percentage of stearic acid, respectively of stearin. . Fats rich in stearin are better adapted for making soap containing rosin than the softer fat and oils. Stearin is a neutral substance, dissolving but sparinglv in cold alcohol and, like stearic acid, is solid at ordinary temperatures. Fats and Oils. 33 Soap made from stearic acid (or stearin) and soda, is very spar¬ ingly soluble in cold water, but quite soluble in hot water. Palmitic Acid and Palmitin : These have a great resemblance to stearic acid and stearin respectively and, like the latter, pal¬ mitin is a constituent of most vegetable and animal fats, being especially abundant, however, in palm oil. Palmitic acid is somewhat lighter than stearic acid, melts at a temperature about 12° F. below that required for the latter, and forms at ordinary temperatures an odorless, tasteless, colorless, brittle and crystal¬ line mass. It is insoluble in water, but easily dissolved by boil¬ ing alcohol. Palmitin is neutral, insoluble in water, and almost insoluble in alcohol; at ordinary temperatures it is a solid body, melting at a somewhat lower temperature than stearin. Oleic Acid and Olein : Like the preceding two fatty acids, oleic acid is found in most of the natural oils and fats. It is insoluble in water, but readily soluble in alcohol, and when pure it is devoid of odor, taste and color. It differs greatly, however, from stearic and palmitic acids in being liquid above 39-40° F. (below that temperature it is hard and crystalline), and a large proportion of oleic acid in any fat tends to make it more fluid. Olein differs from stearin and palmitin in being much more soluble in alcohol, also somewhat slower to combine with alkalies to form soap. The soap it forms with the alkalies is much softer and more easily soluble in water than stearin soap. Laurie Acid: This is a fatty acid found in cocoanut oil and some other oils. It melts at about 110° F., forming a thin oil which, on cooling, turns into a crystalline mass. Laurin ( = Laurostearin) melts at about the same temperature, but on cooling it forms a solid, brittle mass, not unlike stearin, it is easily saponifiable. Myristic Acid: This fatty acid also is found in cocoanut oil and in some other fats. It melts at about 129° F. and when cold forms a solid, crystalline mass. Linoleic Acid; Ricinoleic Acid; and Butyric Acid: are among the remaining fatty acids which deserve to be mentioned ; they are characteristic of linseed oil, castor oil, and butter respectively. Mar gar ic Acid , Cocinic Acid: In the older text books mention is frequently made of margaric acid ; this was at one time the name of what is now known as palmitic acid ; then it was applied 34 Fats and Oils. to a supposed newly discovered fatty acid. Later it was held that the substance then known as magaric acid was really only a mixture of stearic acid and palmitic acid, while at present the existence of a special margaric acid is again affirmed by later investigators. So also is cocinic acid a mixture of other fatty acids (lauric and myristic), and not, as was formerly believed, an independent acid. Effect of the va¬ rious fatty acids on the soap. As was said in the foregoing, all fats are mixtures of various compounds. Thus, tallow is a mixture of stearin, palmitin and olein. Bearing in mind the peculiarities of each of these, as above described, it is readily seen why melted tallow, on being slowly cooled, may be caused to separate into a solid and a liquid portion ; the stearin and palmitin solidify, at a temperature at which the olein still remains liquid. This fact is practically utilized in the manufacture of many products, such as the so-called oleo-oil for artificial butter, etc., the liquid olein being separated from the warm fats by filtering it, under pressure, from the solidified stearin and palmitin. In the natural oils and fats the solid portions may therefore be considered as being dissolved in the liquid part, and on cooling slowly the stearin, etc., separate out from the olein, etc., partly by solidifying on account of the low temperature, and partly by crystallizing. It must not be supposed, however, that a fat acts in every manner directly in accordance with the peculiar characteristics of its constituent parts. For instance, it was stated above that stearic acid melts at 156° F. and palmitic acid at 144° F.; a mixture of equal parts of each might be supposed therefore to melt at 150° F.; or it might be supposed that at 150° the palmitic acid alone would melt, leaving the stearic acid solid. But as a fact, the mix¬ ture melts at 134°—a lower temperature than would suffice to melt either oneof the ingredients singly. Furthermore, regardingtheir action in soap making, the fats have a tendency to communicate to a certain extent some of their properties to each other; an oil, for instance, which combines with difficulty only with alkali, will do so more readily when mixed with a more easily saponifiable fat. On the whole, however, it is safe to select fats for soap mak¬ ing according to the characteristics they possess singly, with a view to counteract extreme effects of one fat, by the addition of another fat known to give opposite results. For example, soap from tallow alone forms a lather slowly, but the lather remains Fats and Oils. 35 a long- time; and soap made from cocoanutoil alone lathers very readily, but the lather formed is of very short duration ; but if both fats are used together, they quickly yield an abundant and lasting lather. Tallow soap, during the boiling and later op¬ erations, has a very thick consistency and becomes solid while still very hot, so that for carrying out certain operations requir¬ ing fluidity of the mass, an oil like cocoanut oil, which gives a soap of thin body while hot. is a valuable aid in the process of manufacture. Again, some oils form soaps which are too easily soluble for some practical uses, and in such case the addition of fats forming less easily soluble soap is indicated. These con¬ siderations will be further carried out in detail in the following description of the fats used in soap making, and also in a special chapter devoted to the selection of stock for soaps of different character. Rancidity of Fats and Oils: When fats are exposed for some length of time to the influence of the air and light, they absorb oxygen from the atmosphere, and a portion of them is split up into fatty acids and glycerine. The free fatty acids are then gradually decomposed still further into another series of volatile fatty acids of a rank odor, so that rancid fats are characterized by an offensive smell, and contain more or less free fatty acids. The presence of moisture, either in the fat or in the air, seems not to be absolutely required in order to render fats rancid, but like other foreign matters in the fat, it seems certainly to favor the process. Thoroughly purified fat, deprived of water, is pre¬ served much longer and with less difficulty than the natural products in their crude state. (See Appendix, Note 7.) In place of becoming rancid, some oils (the so-called drying oils) become more solid, forming a transparent varnish. Adulteration of Fats and Oils : It very frequently occurs that soap manufacturers buy fats and oils and work them up into soap without close examination, provided they have a good appearance, when these fats upon investigation would be found to contain impurities or adulterations which detract considerably from the apparent value of the fat as a soapmaking material. These extraneous matters may be merely accidental or frau¬ dulent additions, but in either case they certainly merit much greater attention than they are now accorded by most soapmakers, for whatever may be the nature of the impurity, it signifies a Rancidity of fats. Adulterat ion of fats and oils. 36 Fats and Oils. loss to the soapmaker in every instance, unless properly allowed for in the price of the material. Almost too well known to require special mention here is the adulteration (up to the point of entire substitution) of olive oil by cotton seed oil. A similar case is that of lard; a recent ex¬ amination made in Germany of lard imported from this country showed that out of 110 different lots no less than 77 were adul¬ terated more or less by the addition either of cotton seed oil or inferior qualities of animal fat, so that on an average the alleged lard was only of half its supposed money value. The lower priced fats, which are of greater importance to our soap manufacturers, such as tallow, grease, palm oil and the commercial fatty acids, escape adulteration no less. One adul¬ teration to watch for in tallow consists of mineral soap stock, which is an unsaponifiable residue obtained from petroleum re¬ fineries. Of this material 20 per cent and more may be present in the tallow without injuring its appearance or its consistency to a very great extent, and unless suspected it may not be dis¬ covered without a special test, for a boiled soap made from it would be merely a little softer, while the presence of the foreign matter in the soap would not be easily revealed. Used for cold- made soap a given weight of such stock requires less lye than good tallow, as the mineral impurity does not combine with lye. The soapmaker no doubt prefers buying pure tallow, and possibly add the soap stock to his soap at the price of soap stock , to paying for the latter at the price of tallow. A similar adulteration consists of glucose, of which quite noticeable amounts have been found in commercial tallow and greases. A still more common adulteration of fats consists in the ad¬ dition of water which has been incorporated by the aid of some emulsifying agent, such as soda, potash or lime. A very appre¬ ciable quantity of water may thus be worked into a fat without being detected, except upon close examination. Not only the weight, but also the solidity and the appearance of the fat are thus artificially ‘‘improved.” When soda or potash have been employed for the purpose the loss is simply one resulting from the low yield of soap obtained from the fat; when lime is present, however, a double loss results, from the formation of lime soap in the fat, which deteriorates the quality of the soap made from the latter as well as the quantity. Hager recently reported that Fats and Oils. 37 a certain lot of grease intended for soap making, upon being closely examined by him, was found to contain 18 per cent of lime soap. After saponifying and “cutting” with salt a voluminous precipitate of lime soap was noticed. He concludes by saying that the presence of lime in the fat need not necessarily be the result of fraud, since it is possible that pork infested with trichinae had been treated with caustic lime in order to insure against its being consumed as food, and that on rendering the fat the lime was thus brought into it. For the detection of lime soap in the fat he proceeded as follows : The fat was dissolved in a water bath in five times its volume of petroleum and set aside in a temperature of 15° C. (59° F.) In the course of eight hours a precipitate had formed which was collected on a filter, washed out with petroleum benzine and dried between filter paper. The dry residue is the lime soap, which is soluble in hot, but insoluble in cold petroleum. The partial saponification which is the consequence of ad¬ ulteration by weak lye will be apparent when the fat is melted on water, when little or no clear fat is thereby obtained (but a cloudy emulsion instead) if lye is present. The admixture of cheaper grades of fat to the tallow or grease cannot perhaps be properly called an adulteration, as it lowers the “grade” on which the price is based. Not exactly an adulteration, but rather an impurity, some¬ times contained in tallow, is sulphuric acid which has been used in rendering (for the purpose of destroying the membrane of the suet), and is not always fully removed. Such tallow is apt to be turned yellow in iron tanks, by the action of the acid on the iron. This is more frequently the case with tallow brought on the market by the small country butchers, who have less perfect facilities for rendering than the large slaughter houses. For soap made by the “Cold Process” such tallow is very unsuitable, as the acid present neutralizes seme of the lye and thereby causes disturbances in the process, and badly formed soap. Glue and albuminous matter are frequently found in fats as accidental impurities. In the absence of facilities for complicated tests, or as a sim¬ ple preliminary test for fats suspected of adulteration, the follow¬ ing proceeding will often give useful indications concerning the purity of the fat: A fair sample of the fat is melted and placed into a graduated glass cylinder; into the latter is then poured Preliminary test for adulterated fats. 38 Fats and Oils. Rendering in soap factories. about 35 parts (by volume) of dilute sulphuric acid to 100 parts of fat. After shaking- well, let settle. The pure fat rises to the top, while the sulphuric acid absorbs the impurities and settles to the bottom The graduations marked on the vessel will ap¬ proximately indicate how much pure fat was contained in 100 parts of the sample. The line between the fat and the precipi¬ tate should be distinctly visible, and if it is not so, then the experiment should be repeated with a strong-er acid solution. Of course, this test is of no avail in determining adulteration by cheaper fats, and can only be used in regard to such additions as water, lye, lime, flour, etc. Rendering Fats : Throughout the country there are numer¬ ous soap factories so situated that they prefer to render them¬ selves the tallow and greases they require, as by this means they are not only placed in a position to obtain material of a certain uniform quality, but, under favorable circumstances, to save considerable money besides. The operation of rendering consists in removing the mem¬ branous tissue which envelopes the fat as it is taken from the Fig-. 1. animal carcass, thus separating the pure fat, and may be carried out in many different ways; at present the several methods have Fats and Oils. 39 mostly given way, however, to the uniform system of rendering by steam, under pressure. In former times the operation was carried out in open kettles, 01 (l methods o f jacketed or otherwise, over open fire, with or without the addi¬ tion of water, the raw fat having been previously cut into small pieces. This modus operandi had several disadvantages, such as failure to extract all the grease, the evolution of an extremely obnoxious odor, great inconvenience in manipulation, etc. In¬ stead of using a high degree of heat for the purpose of rupturing the cellular tissue and liberating the fat, dilute sulphuric acid was partly employed later on in several different ways, as this acid has the property of dissolving and decomposing the mem¬ branes; this latter process has since been all but abandoned for rendering any but very small quantities, and steam is now al¬ most exclusively employed for rendering, as follows: The application of steam is made either indirectly, by means of open steam-jacketed kettles (see Fig. 1) or by admitting it directly into the material operated upon in so-called digestors (Fig-. 2.) For the better grades of fat, the jacketed kettles are fre¬ quently preferred, as by direct contact of the steam with the fat the membranes are transformed into glue and the quality of the product is impaired. But while the quality of the fat obtained from rendering in jacket kettles is superior, the quantity is les¬ sened, and for ordinary use digestors are commonly employed, which have the further advantage of allowing of a higher tem¬ perature (by operating under pressure) than is possible in open kettles. The digestors in use are variously constructed as to details, but in their main features they resemble the one here illustrated (Fig. 2.) This apparatus is a closed, cylindrical tank, made of boiler iron or steel plates, riveted strongly so as to safely allow of a high pressure. In size it varies according to the required capacity, a very common size being 10 to 12 feet high, with a diameter of from 3 to 5 feet. Referring to the illustration, M is a manhole, through which the tank is nearly filled with the raw material at the beginning of the operation; this done, the tank is closed tightly. S is a safety valve set at the pressure intended to be used. D D D are cocks by which the depth of the melted fat can be determined and the product drawn off after the operation is finished. A 40 Fats and Oils steam gauge should be attached to the apparatus, unless a sepa¬ rate steam boiler can be used to supply the steam necessary, in Fiar. 2. which case the indications of the gauge of the boiler may be relied on. G is the discharge hole through which the ‘ ‘ tankage” Fats and Oils. 41 is removed ; instead of placing- it at the bottom, as shown in the illustration, it may also be arrang-ed somewhat higher—on the side of the tank—say half-way between the bottom of the cocks D, and just above a perforated diaphragm placed in that portion of the digestor. The diaphragm serves as a support for the fat to be rendered, and at the end of the operation the tank¬ age may be easily removed from it in case the discharge hole is placed on the side ; it it is at the bottom, as shown, the diaphragm must be made so as to tilt when the refuse is to be removed. A pipe is also provided on top, for carrying off the obnoxious odor arising from the operation ; leading this pipe into the fire-box of the steam boiler, between the boiler and the grate, the'odor is destroyed by the flames more effectually than by any other means so far discovered. When the tank has been charged as before mentioned, steam is admitted through the steam pipe shown at the bottom of the apparatus. The pressure at which the steam is used varies ac¬ cording to circumstances, depending on the size of the apparatus, the nature of the stock to be rendered, and on the time that may be allowed ; the higher the pressure used, the less time is con¬ sumed, but as a high pressure (and consequently greater heat of the steam) affects the product disadvantageously, it is ordinarily preferable to use rather more time and less pressure ; 45-50 lbs. in the digestor is probably a fair average of the steam pressure commonly used, rather less being used for low grades of stock, in order to avoid as much as possible the decomposition of various impurities which would contaminate the product. The time re¬ quired for steaming, of course, also varies according to the same circumstances which govern the proper degree of pressure, and may be more or less than ten hours. During this time the steam continuously admitted condenses into water, which collects at the bottom, and may be drawn off frormtime to time through the pipe W. When the operation is finished, steam is turned off and the contents of the digestor are given time to separate and to settle. The melted fat may be drawn off through the cocks D D D, the lower part of the tank being filled with water and with the ac¬ cumulated refuse. The latter is taken out, pressed to regain the last fat it may hold, and dried to be worked up for fertilizing material. Saponification of Fats : By saponification the soap maker 42 Fats and Oiis. usually understands the process of boiling- fats and oils with lye during- which soap and glycerine are formed. But the term is used in a wider sense also to denote any process whatever by which fats are split up into fatty acids and glycerin; the word in this.sense, therefore, includes even such processes in which no alkalies or any other basic substances are employed. Thus saponification in the latter sense (without the formation of soap) may be carried out by the use of water aione, at a high tempera¬ ture ; this process is facilitated by a small addition of an acid or of a base ; most readily, however, is saponification effected by the use of sufficient quantities of a base (soda, lime, potash, &c.) to combine with the fatty acids set free to form soap. Strong sulphuric acid is also capable of splitting up the fats. The var¬ ious forms of saponification, apart from soap making, are em¬ ployed in the manufacture of stearin candles, of plasters, etc. Thus a saponification with water, a few per cent of lye, and a high temperature (in a high-pressure apparatus) is sometimes used to manufacture glycerin and fatty acids, the latter of which are then used to manufacture candles and soaps. TALLOW. Properties of tai- Tallow, especially in this country, ranks foremost among low in soap male- M . , . , . ing . the fats used in soap making, as it posesses many properties which make it particularly well adapted and valuable for the purpose ; but, unfortunately for the soap manufacturer, there is a steadily growing demand for tallow for the oleomargarine in¬ dustry and for the lard “refineries,” so that the better qualities of the stock are too apt to find their way into these channels. Tallow consists of about one-third its weight of olein and two-thirds of a mixture of stearin and palmitin, and is conse¬ quently one of the most solid of fats. The large proportion of stearin also has the effect that the soap made of tallow as the only fat does not lather readily unless the water used with it is hot. (See preceding pages.) But the exact proportions of these con¬ stituents are variable, in consequence of which tallow varies in hardness. Tallow soap gives a very mild and persistent lather, is economical in use, and, while fresh, it is whiter in color in a proportion as it contains more water ; on drying it has a tendency to turn yellow, or even brownish, which may be to some extent prevented, however, by bleaching the stock, or by the addition of some vegetable fat—especially cocoanut oil—to the tallow, Fats and Oils. 43 whereby the drying- of the soap is also retarded. Tallow is easiest to saponify when the lye used at the beginning of the boiling is not of a much greater strength than 8-10° B., and even when the lye is used of this strength only, all through the operation, the resulting soap in the kettle will be much thicker and tougher than soaps of other fats would be even when made of stronger l} 7 e, and therefore, containing less water. Like all commercial articles, tallow varies very much in quality. Its color ranges from white to yellow ; the feeding of the cattle as well as the season, and the breed and age of the animals, each influence its hardness as well as the color and odor to some extent, and the different part of the animal furnishing it, as also the methods and care used in rendering, and the age of the tallow, are of considerable influence on its qualities. In order to extract as much tallow from the raw fat or “suet” as possible, a weak solution of sulphuric acid, or less frequently alkali, is sometimes added to the fat before rendering, whereby the tissues in which the tallow is enclosed are dissolved or charred, and the fatty matter may be extracted with greater ease. But the chemicals, if used in excess, or if not removed by washing afterwards, are apt to injure the tallow as well as to give rise to unforseen irregularities if used for making soap by the cold pro¬ cess. The steam employed in rendering is liable to transform the membranous matter into glue, which is then very likely to remain in the tallow. Moreover the moisture, particles of blood, etc., attached to the raw fat, rapidly deteriorate the quality of the tallow, so that the latter is apt to be rancid, unless rendered as early as possible. Considering then that tallow is brought on the market by large slaughtering houses as well as by numerous small city and country butchers, the varieties and qualities are easily accounted for. In making soap, the tallow used frequently requires to be bleached in order to produce the clear white color so much admired in certain brands. For simply clarifying the tallow it is sufficient to boil it on water (or open steam) to which some salt and some alum has been added ; but this means is not always sufficient for the purpose. Tallow so treated still contains more or less free fatty acids, which attack the iron of the kettle and thereby cause a yellow color of the tallow if the latter is left in an iron vessel for any length of time. The removal of these free fatty acids, which range in proportion from 2 to 10 per cent, is also Bleaching tallow. 44 Fats and Oils. very important when the tallow is to be used for “cold-made” soap; and finally the alum treatment is most effective in an alkaline solution, i. containing rosin. Rosin soap in waste lye. Bleaching rosin. Rosin not an adulteration. 70 Fats and Oils. facts in the matter will readily show. First of all; the yellow rosin soaps are so very extensively made simply because the de¬ mand for them is greater than for any other kind of soap for laundry and general household purposes; this in itself would seem to demonstrate that rosin confers some desirable properties on soap. Secondly, the fact that rosin is cheaper by the pound than fats and oils does not of itself make it an adulteration, so long- as it is used in proportions suitable for the purpose. Third¬ ly, as rosin consists of acids that are capable of forming- a soap, its use can no more be considered an adulteration than the use of red oil, or cheap grease would be. Rosin can therefore be consid¬ ered as an adulteration only when the soap is supposed to be made of hig-h priced fats alone, and a corresponding- price is paid therefor. Certainly no soap, other thing's being- equal, will do washing at as low a cost and with as little effort as a soap will do which contains a moderate proportion of rosin. For use in cold water, or in hard water, rosin soap is in many respects un¬ surpassed. The rather agreeable odor of rosin soap as compared with a pure tallow soap also deserves mention. In combining- with lye, this material yields an amount of soap slightly below that g-ained from a like amount of fat; the exact g-ain cannot be given, as the commercial grades of rosin vary greatly. (Rosin oil, obtained by redistilling rosin, is a hydrocarbon compound, and not saponifyable). CHAPTER III. Lye. Lye is a solution of alkali in water, and may be of greatly varying- composition, as regards strength as well as quality . The more alkali is dissolved in a given quantity of water, the heavier will of course become the lye, and for ordinary use the strength of lye is therefore gauged directly by its weight. Avery conve¬ nient instrument for the purpose of ascertaining the weight is a “hydrometer” or “alkalimeter” (see illustration), which is a glass tube, closed at both ends, and provided with a weight on one end and a graduated scale on the other; the latter serves to show how deep the instrument sinks into the lye, being so graduated that it indicates 0 in pure water, and higher numbers (degrees) as it sinks less deeply in the liquid, or in other words, as the lye becomes stronger. As the instruments commonly sold do not al¬ ways register quite correctly, variations of a degree or so being by no means rare, it is well to compare new instru¬ ments with those already in use, before breaking of the latter throws all the responsibility on a new hydrometer whose accuracy was not tested. The graduation, as bx £ mostly used in this country, was designed by Baume, and the strength of alkaline and other solutions is therefore generally described as being “so many degrees Baume,” meaning that the instrument described sinks to that degree of its scale into the lye. In England a different graduation, namely that of Twaddle, is more generally in use. In order to form a correct idea of the real strength of any lye it is, however, necessary to also consider the nature or quality of Quality and strength of lye. Strength alone is no real indica¬ tion of the char¬ acter of lye. 72 Lye. the alkali of which the lye was made, for the alkalies of commerce are brought into the market into several grades, containing vary¬ ing proportions of pure caustic alkali, and since they correspond¬ ingly contain varying proportions of carbonated alkali, salt, sul¬ phate of soda, and other impurities, it follows that two lyes of the same weight may differ considerably in their nature as well as actual strength, even though the indications of the hydrometer be the same in both. Moreover it is necessary to take into account the fact that the density of the same liquid varies with its temperature. The difference of a lye at 60° F. as against the same lye at boiling point is to 4° on Baume’s scale; this is of little moment in making boiled soap but becomes important when testing the strength of lye to be used in the cold or half-boiled process, or for transparent soap. It should hardly be necessary to say that where accurate testing is necessary, the instrument should be dry, and especially free from grease, before placing it in the lye; carelessness in this respect is as bad as the use of incorrect instruments, and has caused many batches of cold soap to be spoiled. In order to be a little more explicit we must now consider the commercial varieties of caustic and carbonated soda and potash. Grades of Alkali'. Caustic soda is brought on the market in commercial grades named respectively 60, 70, 74, 76, and 77% the highest grades of alkali. . . . and almost chemically pure commercial grade of caustic soda be¬ ing the 77% grade. To understand these denominations it must be remembered that 100 lbs. of pure caustic soda are formed by the combination of 77% lbs. of sodium oxide with 22% lbs. of water, and as the percentage of sodium oxide in a sample is the numuer expressing the grade, it follows that chemically pure caustic would grade 77 %%. Itshouid also be remembered that this mode of indicating the grade is in use in England and in the United States, while in Germany the percentage of sodium car¬ bonate , which would be equivalent to the oxide, is named as the grade; iriFrancestillanothernotationis used which itis not neces¬ sary to describe here in detail. (See Aop. Note 8). On a sim¬ ilar principle as in the case of caustic soda are also designated the grades of carbonate of soda (soda ash etc.) and the analog¬ ous compounds of potash, so that soda ash ranges from 25 to 58 per cent in grade. As to ordinary commercial American potash, its composition Lye. 73 is but too often a somewhat mysterious one, as very variable pro¬ portions of soda alkali, common salt, and sometimes lime are pre¬ sent. Unless an article of known purity be purchased, it will be necessary to carefully examine the potash used in order to obtain expected results. While a grade containing- 70% of potassium hydrate on an average is insisted on by larg-e buyers, lots are frequently found that averag-e only 60% and less, containing- a correspondingly high amount of ordinary salt. A good grade, moreover, is generally opaque, of dull gray or slate color, often with green or red stains, and is sometimes honey combed, while that containing much salt has a much better appearance, being nearly white, pearly and translucent, so that potash is very like¬ ly to be misjudged by its appearance. These remarks do not apply to the uniform products imported from Germany and France which are sold under a strict system of grading. Quality of Lyes : To illustrate more plainly the difference in lyes made of the various grades of caustic, let us look at the com- position of the latter: There are contained in 100 lbs. of commercial Composition o CB-UStlC caustic of differ soda of 60-62% 70-72% 77% ent grades. (Pure) Caustic Soda, about.. . 73 lbs. 86 lbs. 97 lbs. Carbonate of Soda, about.. . . 2lbs. lbs. Ordinary Salt, about. 5 lbs. fz lb. Sulphate of Soda, about. 4 lbs. /4 lb. And small quantities of other substances, such as sulphite and silicate of sodium, etc. The composition as shown above is subject to slight varia’ tions, but at all events the table shows that a lye made of 60-62% caustic soda is of a very different character than one made of 70-72% caustic, even though both indicate the same strength on the hydrometer. This difference is of course still greater with soda of 76%, and is moreover of much greater practical impor¬ tance to the soap maker than is at present realized in many in¬ stances. In fact this difference can hardly be sufficiently empha¬ sized or made plain enough, for the erroneous belief is very wide¬ ly and persistently held that not only the quality of a lye could be told by the hydrometer, but that even caustic could be tested by observing whether or not a given amount of it dissolved in a certain amount of water will show a certain degree on the hy¬ drometer; such belief is entirely without foundation. 74 Lye. Effect of foreign saltson tliesoap in the kettle. The best grades required for the cold process. Lye for saponify¬ ing red oil and rosin. Grades of caustic commonly used. Effect of Lyes of Different Quality : The ordinary salt, the sulphate and the carbonate of soda, etc., contained in the alkali, being' unable to form a chemical combination with the neutral fat or oil, remain simply mechanically mixed with the particles of soap formed during- the process of soap making-, (the carbon¬ ate of soda may combine, however, under favorable circumstan¬ ces, with free fatty acids, if any are present), and the presence of this admixture has in the first place the effect of rendering the soap in the kettle more mobile and liquid. When fats are boiled with a very high grade of caustic soda, that is to say with soda containing but a very small proportion of foreign salts, the re¬ sulting soap will be comparatively tough and thick, more diffi¬ cult to manage in the kettle, and of a more or less brittle grain when finished. The greater mobility of the fluid soap when boil¬ ing, if the lye used was made of medium or low grade caustic, is an advantage in promoting the contact of lye and fat. In the “cold process” of soap making, however the reverse, is true, for in consequence of the necessarily limited time allowed, and the imperfect and slow motion of the mass during the operation of mixing, the best cold-made soap naturally results when the high¬ est grade of caustic lye is employed, so as to permit the thorough contact of lye and fat, without the interference of foreign inert matter. As rosin and red oil, unlike the neutral fats, combine with carbonate as well an with caustic soda, mobility while boil¬ ing these materials with lye is insured by either the addition of salt in the kettle, or by taking care that there always be a sur¬ plus of uncombined lye in the kettle, which then—until it com¬ bines—has a similar effect, as the carbonate has when neutral fats are being saponified. In boiling soap a medium grade (70-72%) of caustic is therefore most generally employed al¬ though many prefer 60% caustic to the higher grades, for all ordinary purposes, as the foreign salts in this grade cause easier and freer working in the kettle; still others use the medium grades and add salt to the lye while boiling, to obtain the same result, a practice which is as strongly condemned by some soap makers as it is recommended by others. The lower grades are less economical in use, as will be explained below, and ordinarily have no particular advantage for soap making purposes over the medium grades. Where waste lye is to be worked up for glyce¬ rin the foreign salts present in it sometimes form a considerable item in respect to the cost of their separation. The carbonate Lye. 75 of soda of spent lyes may be utilized by boiling’ some red oil or rosin or rancid fat. on the lye after all the caustic strength has been bound; unless this is done the carbonate will be lost in the waste lye that is run away. The various salts contained in commercial caustic soda, which are incapable of combining - with fat, furthermore have this property that on dissolving - in water they render the latter more and more incapable of holding - soap in solution, so that soap may be separated from its solution in water by adding enough salt, carbonate of soda, or even an excess of strong - caus¬ tic lye, to the contents of the kettle. The presence of moderate quantities of foreign salts in the soap is of advantage not only while boiling, but is absolutely re¬ quired—for mottled soaps—when the finished soap is run into the frames to mottle while cooling ; the mottle is formed by the stearic acid soap crystallizing out of its solution in the oleic acid soap, and without the presence of foreign salts in proper propor¬ tions the soap would not possess sufficient mobility to allow of proper crystallization ; the mottle would be a failure. Too much of the foreign salts, on the other hand, gives rise to certain dis¬ turbances (especially in soaps not containing cocoanut oil), de¬ pending partly on the diminished capacity of the soap to retain the water in its composition, and partly on the property of these salts to come to the surface of the cakes of soap while drying, and appearing there in minute white crystals, covering the soap with a white film. They also attract moisture from the atmos¬ phere and cause the soap to “sweat” in consequence, in certain weather. In preparing lve, it is convenient and advantageous to use, when possible, the condensed water from the closed steam coil, as this water has been distilled and is consequently free from the lime and magnesia compounds whose presence gives rise to the formation of insoluble soaps, as explained in a previous chapter. The composition of the lye being of considerable influence on the properties of the soap turned out, the following general observations will be found useful : The several fats are not equally sensitive to the action of foreign salts in the lye ; for instance, cocoanut oil soap as has already been pointed out—is capable of holding a considerable quantity of salts and water without appearing the worse for it, particularly while still iresh; if a similar quantity of salt solu* Saving the car* bonate. Effect of foreign saltson thesoap in the frames. Excess of foreign salts. Different effect of foreign salts with different fats. 76 Lye. tion were added to tallow soap, the latter would—if not separ¬ ate entirely from the solution—certainly dry out very rapidly, become very hard and brittle, and covered with the crystals of the salt. In a general way, however, the following properties may be ascribed to the different salts and alkalies: Pure Caustic Soda : Tends to cause a tough consistency of the soap-in the kettle; a considerable excess (/. c., too strong lye) drives the soap out of solution. The finished soap is hard, com¬ paratively dry, and owing to its toughness, more likely to con¬ tain particles of unsaponified fac, as well as to crack on drying, unless the saponification has been very carefully conducted. If present uncombined in the finished product, the soap will be very hard and unfit at least for the toilet. Carbonate of Soda : Gives the soap greater mobility in the kettle, facilitates saponification if present in moderate quantity, and if in great excess, separates the soap from the tye. It com¬ bines with free fatty acids, but not with neutral fats. It present in the finished soap it inclines more than any other salt to come to.the surface of the cakes when the water dries out. Still, a considerable quantity of the carbonate may be incorporated into a soap after boiling without this latter difficulty, managing so that the soda crystallizes in the soap, thereby hardening it and pre¬ venting the carbonate from coming to the surface; this will be more fully described in the chapter on “Settled Rosin Soap.” Its presence has a less marked tendency to make the soap brittle than does common salt, and it is therefore sometimes employed together with the latter, in boiling down “ mottled ” soap. Crystal Carbonate is a product differing from sal soda by contain¬ ing only about 17% water as compared to 62% m sal soda. Common Salt: This, more than any other salt, renders water incapable of dissolving soap and is therefore used largely as an addition after boiling, in order to separate the soap in the kettle from the waste lye. The salt dissolves in the waste lye, and with the exception of a very small amount, settles out again. Common salt also makes soap more brittle by its presence than does any other salt. It is for this reason that some soapmakers prefer to use some carbonate of soda in the salt pickle for boiling down mottled soap. It is sometimes found among the crystals formed on the surface of some soap, and indeed soap containing common salt inclines to effloresce. In settled rosin soap especi¬ ally the presence of appreciable quantities of salt si disturbing, Lye. 77 and when such soap is filled with sal soda and perhaps silicate of soda also, cracking - and “whitewashing - ” are very apt to be the result. For this reason some manufacturers prefer to use strong lye, instead of salt, for separating soap from the waste lye, as traces of salt will always remain. Potash : The potash compounds acts similarly to the ana¬ logous soda combinations, but in every respect more mildly. Thus common salt (chloride of sodium) precipitates soap from its solutions, and renders it brittle, much more energetically than does chloride of potassium. Soap containing a proportion of potas¬ sium salts instead of being made with soda exclusively, is softer in consistency, more easily soluble in water, milder in its effects, dries out less, effloresces less easily, and is of a tougher*»texture than that containing only soda salts. In fact, the substitution of potash in any hard soap for a part of the soda is an improve¬ ment, and would probably be a universal practice but for the higher price of potash compounds. But in calculating the com¬ parative value of potash and soda for soap making, it should be remembered that considerable more potash than soda is required to saponify a given amount of fat; consequently the higher cost of potash is at least partly compensated for by the higher yield of soap caused by the presence of the increased amount of alkali. A quantity of fat requiring 40 lbs. of soda to form neutral soap will absorb 56 lbs. of potash for the same purpose, and will thus furnish 16 lbs. more of soap (the proportion of water present be¬ ing considered the same in both cases). Soap made entirely with potash is known as “soft soap.” A potash soap, however, if separated from the waste lye by means of common salt (chlo¬ ride of sodium), will undergo a remarkable change; it will be¬ come a soda soap, and the waste lye will contain chloride of po¬ tassium, instead of thechloride of sodium. This chemical reaction is only a partial one though, and a soap made in this manner still contains considerable (about 50%) of potash soap. At the time when wood ashes were almost universally used for soap making, the hard soaps were manufactured in just this manner, and a better grade of soap it would be hard to make, owing to the im¬ provement made in the grain, texture, etc., by the potash still present. (App., Note II.) A similar result is now sometimes obtained by using potash and soda lye together in saponifying fats, or—a less recommendable practice—by adding a carbonate of potash solution to a finished soap. When potash solution is Substitution o i potash for soda. More potash re¬ quired for sa¬ ponifying a given weight of fat thanasoda. Peculiar effect of salt on potash soap. 78 Lye. Proper strength of lye partly de¬ pends on the mode of apply¬ ing steam. added to soda soap, part of the latter is transformed into potash soap, whereby the effect of potash on a soap so treated is ex¬ plained. (App., Note 11.) The Effect of Lye of Different Strengths : As was said in the foregoing chapter, facts do not all require the same strength of lye to combine easily, but they all agree in readily taking stronger lye as saponification proceeds, than they will combine with at first. Thus tallow combines most easily at first with lye of not much over 10° B. in strength, if made of low grade caustic; but when saponification has once been induced, the strength of the lye can be rapidly increased up to 2(L B. and over. Cocoanutoil combines most readily with strong lye. The stronger the lye used, the less water is unnecessarily introduced in the kettle, and the more easily is the soap managed. Too weak lye, in other words too much water, is also apt to induce frothing, more especially with the use of open steam for boiling, which adds the condensing water to the boiling mass. With closed steam alone weaker lye must be used, of course, than when open steam is used also. Cost of Lye : Apart from their greater serviceableness for most purposes, the medium grades of caustic soda are also pre¬ ferable on account of greater economy. The low grades are higher in price than the medium, because of the cost of freight, packages and other expenses on the foreign salts contained in the former, which after all are lost in the spent lye. The higher grades are more expensive because of greater difficulties in their manufacture. The cheapest way to buy caustic alkaline strength is undoubtedly by obtaining caustic soda of about 70-72%; or the manufacturer may buy soda ash to advantage and causticize it himself, as described under “Lye Tank” in Chapter V. Ammonia , although in its behavior closelv allied to soda and potash, is incapable of saponifying a neutral fat; it can only form an emulsion with the latter, from which the ammonia se¬ parates again on resting. But free fatty acids (as red oil) can be saponified by crutching in ammonia; soap so formed will, on drying, have a consistency intermediate between potash and soda soaps. CHAPTER IV. Filling Materials. A number of substances are frequently introduced into soap for certain special purposes, among- which those intended pri¬ marily for cheapening- or “filling-” deserve separate mention. It may not appear rig-ht to add any such materials to soap, at least when the object is simply “ adulteration ” but on the other hand it is a fact that many manufacturers have failed in their attempts to create a demand for their brands of pure soap, which were specially made with the object to improve their pro¬ duct, and owing- to the demands for cheap soaps they are—much ag-ainst their own wishes—finding- better sales for their “ filled ” soaps than for the pure g-oods. Having- once been introduced, the manufacture of this class of g-oods is no longer a matter of choice on the part of the soap maker. Talc , also known as Soapstone, French Chalk, or Steatite. This material has a peculiar greasy feel, not unlike wet soap, whence probably the name “ Soapstone,” and is a silicate of magnesia (about 60 per cent silica and 30 per cent magnesia), with iron, lime, and other impurities mined in this country and also largely imported from France and Italy. It is added to some soaps to the extent of forty per cent (that is to say, 40 lbs. to 100 lbs. of pure soap), but smaller quantities are generally used. It has no value for cleansing purposes and is added principally to make weight; however, in small proportion it has at least the advantage of making the soap mild and agreeable to the skin; by absorbing water it solidifies the soap, causing the latter to preserve its appearance and shape better on drying. It has the disadvantage however, of causing white soap to turn grayish on Pure soap not al¬ ways the most saleable. 80 Filling Materials. drying-, while colored soaps are less brilliant and clear when filled with talc. It is for this reason frequently used in combin¬ ation with silicate of soda; moreover it is a troublesome material if the scraps of such soaps are to be used up by remelting-. Furthermore, the mag-nesia in talc may be partly replaced by¬ lime, and this and similar variations bring- about different quali¬ ties which are not equally adapted for use in soaps. For cold made soaps the talc is generally sifted into the melted fat, or first well mixed with a part of the fat and then stirred into the bulk. To improve the texture of such soap it may be found to be of advantage to stir the talc into an equal weight of boiling 2 C lye and add this (when cooled sufficiently) to the soap when the last lye has been added; such soap is softer at first but dries rapidly in its outer layers and does not soon become so very hard. Incidentally it may be noted here that talc is a convenient ma¬ terial to cover up various metal instruments, cutting wire, and the like, to protect them from rust or verdigris). On keeping talc it should be preserved from moisture, as otherwise it will come to contain many lumps, and will even form lumps in the soap though it be sifted into the fat. Silex, or Silica. This is a mineral which constitutes quartz and most varieties of sand; it is used for filling soap in the form of a very fine white powder. Silex has no detergent properties, isdnsoluble in water, and gives the soap—besides weight—a sur¬ face which feels somewhat rougn. In applying it, it is simply stirred into the soap, mixed with water. Silicate of Sot/a, also Water Glass, or Soluble Glass. This is a compound of silicic acid and soda, and is made by fusing to¬ gether sand and alkali. It is in the market in the form of a dry powder, but more ordinarily as a thick, syrupy solution. Of it¬ self it is really colorless, but from the process of manufacture there frequently remains some foreign matter which gives it a yellowish tint. Its use is greatly to be preferred to silex, for silicate of soda has some detergent property of its oAn, owing to the alkali in its composition; besides it renders some hard water softer, thereby avoiding waste of soap. Silicate of soda is made in several forms and of various degrees of concentration (measured by the hydrometer) and may be easily diluted with water. It is generally used at a strength of about 40° B., but varies somewhat in composition, containing more or less alkali in excess. If weak in alkali it is sometimes necessary to add a Filling Materials. 81 pound of 38° lye for every 5 lbs. of silicate used in the soap, in order to prevent the silicic acid from crystallizing- out. Fresh soap filled with silicate has a better appearance than one filled with talc, but on drying- it becomes harder, lathers less, and- is sharper on the skin. Cold-made soaps containing- silicate are apt to have soft, spongy parts or even free fat collect in the cen¬ ter if run into larg-e frames, especially so if an excess of lye is not used, or when the proportion of silicate added is small; such soaps are therefore best run into small frames. Silicate of soda is frequently used tog-ether with talc. Silicate of potash is a similar article, and sometimes em¬ ployed for filling- soft soaps. Being- made with the more ex¬ pensive potash, it is naturally more expensive than is silicate of soda. The form of silicate of soda most commonly employed by soap makers is known as “N” silicate, which has a strength of 39—40° B. and is sold ready to be used just as it comes from the barrel. For cold-made and half-boiled soap almost any desired amount may be added, from 30 to 50 lbs. to 100 lbs. of fat being a common proportion. In settled rosin soaps from 5 to 10 per cent, of the weight of soap is most generally used, together with a like amount of carbonate of soda solution. “ K ” silicate is a similar preparation, somewhat milder and thinner than the“ N” (36° B.) and also ready for use as it comes. “ S ” silicate is an old fashioned form, of the consistency of a jelly, but chemically similar to the grade “K” It requires melting by open steam and is but little used by the soap makers at present. Starch is sometimes used in soap, but more for the purpose of binding the materials together than as an adulteration. By stirring starch into, say, like proportions of sal soda solution and silicate of soda, and boiling on open steam (in a closely covered kettle, to prevent it from jumping out) a thick mass is obtained which may be used in almost any proportion desired. By boil¬ ing in this manner, the starch absorbs much water and the filling is in every way more desirable than if the starch were used without having been boiled previously. Starch and flour, how¬ ever, have this disadvantage that in the course of time, say a few months, they undergo decomposition, giving rise to a bad odor, and in severe cases even to fungoid growths on the surface of the soap. In cold soap also starch may be used by mixing it Varieties of sili¬ cate. Preparing starch for filling. 82 Filling Materials. well with the melted stock before running- in the lye; for the purpose of thoroug-h mixing- the starch must be dry. Mineral Soap Stock , a by-product obtained in petroleum refin¬ ing-, is used to a considerable extent in filling- soaps. It is in¬ soluble in water and has no deterg-ent properties. Being- a min¬ eral product, it cannot be saponified. sai soda not an Soda Ash, Sal Soda (Washing- Soda) is not, strictly speaking-, aduiteiation. a mere cheapening- ingredient, for it hardens the soap in which it is introduced, contributing to economy in its use and adding to its cleansing power. The use of this material is fully de¬ scribed in Chapter VII. For laundry soap this is undoubtedly the best filling material known, so far as the qualtity of the pro¬ duct is concerned. In washing with hard water the sal soda is quicker to act on the lime salts contained therein; it neutralizes them, and thereby saves much soap from being decomposed and wasted. . Sulphate of Soda (Glauber’s Salt) has a similar effect as sal soda on the hardness of the soap, but it is different in that it has no washing power, does not neutralize the salts of hard -water, and that it is less liable to effloresce. Common Salt hardens soap made largely of cocoanut oil and containing much water. It is not used very much as a filling in this country, however, but is quite common in cheap grades of cocoanut oil soaps made in Europe. Carbonate of Potash (Pearl Ash) dissolved in water is used in some soaps as a filling material, softening the soap, improving its texture and lathering property, and making it somewhat transparent. (Its tendency to soften the soap mav be counter¬ acted by the additional use of salt water , which is also used as a filling in some soaps containing much cocoanut oil.) It absorbs moisture, however, from the atmosphere in damp weather and spoils the wrappers thereby. Borax is a useful addition, especially in laundry soaps, as it renders fabrics very white without affecting their fibres or deli¬ cate colors. It is a white, mildly alkaline mineral, which ren¬ ders the soap more effective without attacking the skin in wash¬ ing. In laundries it is used extensively in place of the sharper soda. ***** The above-mentioned substances are those most ordinarily Fiujng Materials. 83 used, either for filling- or for increasing- the deterg-ent power of soap. To this list may be further added : Sugar, Glycerin, and Alcohol for transparent soaps ; Vaseline (also Glycerin), and Wax, for emolliency ; Sand, Pumice Stone, Tripoli, etc., for scour¬ ing- soaps; Sulphur, Tar, etc., for medicated soap; Ammonia, Ox¬ gall, Benzin, etc., for removing- spots from clothes; and a long* list of substances, such as china clay, flour, dextrine, bran, oatmeal, etc., which are added either as a simple adulteration, or for their (mostly imag-inary) beneficial effect in certain cases. Formulas for using- mixtures of these various fillers will be found on other pag-es, in connection with the description of various soaps. VARIOUS OTHER MATERIALS. Alum: This substance is mentioned in several places in this book in connection with the purification of fats. It is a sulphate of alumina and potassium and its effect is to combine with impurities of the nature of g-lue and to precipitate them. Infusorial Earth : This substance, as it comes from the mines, contains from 75-82% of silica, and more or less of alu¬ mina, iron compounds, org-anic matter, and moisture. It is cleaned, ground, dried and sifted for use in scouring- soaps. It is the same substance which is so often spoken of in connection with nitro-g-lycerine in the manufacture of dynamite. Tripoli is a diatomaceous earth, or in other words it is a de¬ posit of the siliceous envelopes of fossil diatoms and consists chiefly of very finely divided silica. It is used principally, so far as soaps are concerned, in scouring- soaps. Fuller's Earth : This is a kind of bluish-gray to yellowish- green clay noted for its usefulness in the process of fulling cloth in which it is valuable by its absorption of oil and grease; for this purpose it is now largely superseded by soap, but has come into extensive use in its turn in the treatment of oils and fats, as hereafter noted, before these are made into soap, etc. Fuller’s earth is found in Florida, New York, South Dakota, and several other states, and large quantities are imported from Europe. It is claimed that the English earth is superior for deodorizing fats, but that for decolorizing the American product is more ef¬ fective. The clay is used after grinding it to 120 mesh or finer, crutched into the hot oil and removed again by a filter press 84 Filling Materials. which takes out the coloring - impurities which adhere to the earth. The action of this material is mechanical rather than chemical, and is best obtained when the clay contains the least possible amount of moisture. The composition of various kinds varies, being - approximately: Silicic acid 50% to 60%; alumina 15 to 30%; iron oxide 3 to 5%; quartz 10 to 13%; moisture 9 to 18%; with small amounts of lime, magnesia, etc. To examine a lot of this material for its quality, the easiest and most reliable method is to make a small trial test. Sometimes it happens that a stock is bleached with this material and looks very white, but the soap made from it by boiling is as dark as if unbleached stock had been used; the true explanation of this is doubtful, but in view of the iron oxide contained in Fuller’s earth it is possible that free fatty acids in the stock give rise to iron soap which contaminates the product. A preliminary removal of these fatty acids by bleaching with lye, as described under “tal¬ low,” will largely remedy this. Heating the Fuller’s earth be¬ fore use, to drive off moisture, increases its effect. Alcohol : Alcohol is used in the soap factory for a variety of purposes. The officinal alcohol of the U. S. Pharmacopoeia contains in 100 parts 94 volumes of absolute alcohol, (this being equal to 91% of alcohol by weight.) To reduce an alcohol of given percentage to a lesser one when the percentage is reckoned by volume , the following rule has been given by Dr. W. H. Pile. Multiply the quantity of the alcohol (either in fluid ounces or in gallons) by the percentage strength and divide by the re¬ quired percentage; the quotient gives the quantity to which the alcohol must be diluted by the addition of sufficient water. The same author gives the following : To make a definite quantity of any desired strength from a stronger alcohol: Mul¬ tiply the required amount by the required percentage and divide by the percentage of the given alcohol; the quotient gives the quantity to which the alcohol must be made up by the addition of water. It will be noticed that the quantity of water is not definitely stated in either case; to do so would necessitate impracticable calculation for the contraction in volume which occurs on mix¬ ing alcohol and water. Proof spirit contains 52)4 per cent, by volume of pure alco¬ hol and is a mixture of 49 parts by weight of pure alcohol with Filling Materials. 85 51 parts water. This is the strength of the proof spirit usually employed, but by law proof spirit is equal parts by volume of absolute alcohol and distilled water, having a specific gravity of .9 j> 3. The Internal Revenue Law of the United States provides that proof spirit shall consist of a mixture of equal volumes of water and alcohol, the latter having a specific gravity of “seven thousand nine hundred and thirty-nine tens of thousands at 60 c F., ’ water at its maximum density being taken as the unit. This alcoholic liquor will have a specific gravity of 93,353 at 60° F., water at its maximum density being taken as the unit, and will contain by weight 42*7 per cent, of absolute alcohol. A gallon of this spirit weighs 7*77 pounds; 42*7 per cent, of 7*77 pounds is 3*31 pounds. Thus we see that a gallon of proof spirit in the United States contains 3*31 pounds of absolute alcohol. Dilute alcohol (U. S. Ph.) consists of equal measures of officinal alcohol and water; it contains 39 per cent by weight, or 46.33 per cent by volume, of pure or absolute alcohol, and has a specific gravity of .941, equal to 19 of Baume’s light hydrometer. Water: Water freezes at 30° F., and boils at 212° F., un¬ der ordinary atmospheric pressure. Owing to its peculiar prop¬ erty of expanding in the act of freezing, tanks and pipes fre¬ quently become leaky in very cold weather. Another notable property of water is its very great power of dissolving the most varied substances, to which circumstance is due its varying quality, for obviously the opportunity of thus becoming charged with various salts, gases, organic impurities, etc., is very differ¬ ent in the cases of spring, river and lake, or rain water. Water rich in dissolved carbonate and sulphate of lime and magnesia is known as hard water and these salts may be present in it to the extent of 1 %\ they interfere with the solubility of soap in the water and have various effects of practical importance which will be noted in the following pages as occasion demands. On boiling hard water carbonate and sulphate of lime are precipi¬ tated and in the boiler give rise to “scale.” (See App. Note 10.) Li??ie : In burning carbonate of lime (chalk, oyster shells, etc.,) the carbonic acid escapes and there remains calcium oxide or burnt lime; if water be now added to the latter the hydrate is formed. (See App. Note 18.) The caustic lime is used to abstract carbonic acid from soda ash, in other words to causticize soda, a process described in detail on another page. As burnt 86 Filling Materials. lime has the same tendency to absorb water and carbonic acid from the air (and to become more or less ineffective thereby,) it is necessary to either use it fresh or to protect it from such ab¬ sorption. Salt : Ordinary salt (sodium chloride,) is very largely in use in the soap factory—to say nothing- of the fact that the soda of commerce is made from it. It is very soluble in water, but almost insoluble in pure alcohol. As the commercial article is practically always satisfactory, there is no need to go into further details in this place. CHAPTER V. The Soap Factory. LOCATION. In deciding- to establish a soap factory anywhere, it is taken for granted that due attention has already been paid to such ques¬ tions as the cheap supply of fuel, sufficient and suitable water, the facilities for obtaining tallow, &c., at the lowest rates, and shipping facilities for the finished products on the other hand; so we may pass these over now with merely mentioning them. ARRANGEMENT. The conditions determining the internal arrangements of a soap factory are so variable, that it is very little to the purpose, practically, to attempt the description of any one well arranged establishment of this kind. The quantities and varieties of soap turned out, the raw materials used, and the machine^ available for the pnrpose, as well as the facilities of thebuilding in which the factory is located, all have their peculiar bearing on the pro¬ per arrangement and equipment of the works. However, the avoidance of all unnecessary work being demanded alike by con¬ venience and economy, a good rule which has been found to ap¬ ply under almost all circumstances, is to elevate the raw mate¬ rials at an early period to the upper floors of the factory, so that in the successive stages of manufacture they may descend by means of their own gravity to the lowest floor, whence the soap proceeds in the course of cutting, drying, pressing and packing, to the last (shipping) room of the factory, thus obviating as far as possible all pumping or repeated lifting on the elevator, the goods passing in natural order from one machine to the next, General rules gor* erning arrange¬ ment of factory. 88 The Soap Factory. without covering- the same ground repeatedly. In building's oc¬ cupying- only little ground, so that there is not room on the low¬ er floor for the operations of cutting-, etc., mentioned, the frames of soap are g-enerally broug-ht to a higher stor} 7 by the elevator and there cut, pressed and packed, and brought into the shipping room by means of the elevator or a chute. In large factories it is moreover found to be most economical to have separate engines in the several parts of the building where steam power is used, to obviate the use of much shafting and belting. Another point requiring attention is an economical arrangement by which raw materials and fuel can be easily brought to their proper place in the factory without unnecessary handling. Further than this there is probably no general suggestion regarding arrangement that can be made, which will hold good in all cases. We will therefore, after a few words regarding the building, proceed to a description of the machinery placed in the factory, leaving the arrangement to the judgment of the practi¬ cal soapmaker, who will suit his particular circumstances. THE BUILDING is in many cases one originally designed for another purpose than to serve as a soap factory, or it may have been erected be¬ fore a practical soap maker was consulted, or the growth of a business already established require additions which complicate the problem, so that it is often necessary to adapt the arrange¬ ment of the machinery to the conditions alread} T existing. This is obviously less rational than to construct or select the building in accordance with the necessary machinery, &c. The very first requirement should be that the building be amply able to carry the often enormous weights concentrated in the upper stories, as water tanks, lye tanks, kettles, &c. This should be too self-evident to require mention, but several very serious and even fatal accidents that have followed imperfections in this respect amply justify this remark. For a medium-sized factory the building should have at least two stories, or a story and basement, though a 3-or 4-story build¬ ing is the most convenient and practical, being preferable to a low building occupying a larger floor space. In any case the boiling is carried on in the upper story, the kettle passing through the floor into the story below, and the crutcher is placed on the same'^floor in such a manner that the soap can be taken out into The Soap Factory. 89 the frames on the floor below; the boiling- floor; this arrangement enables the soap maker to keep watch of the kettle and of the crutcher, sal soda tank, &c., at the same time. The cutting, drying, pressing and wrapping may then be carried out on the next lower floor. The elevator should go up above the main roof and connect with a small shed above the roof, so placed as to facilitate bringing the rosin into the kettle by way of a chute. One such chute can be made to supply two kettles, by suspend¬ ing it from the middle and shifting its direction as needed by means of ropes at each end, running over pulleys connected with the ceiling. To each end of the floor of the chute is bolted a flat trian¬ gular piece of hard wood, to assist in spreading the rosin over the surface of the kettle. It may also be convenient to have a chute leading from the shed on the roof down to the fireroom, so that rosin staves can be dropped down without further handling. Tallow and oils, when steamed out, being best run into a settling tank (described further on), the latter—in low build¬ ings—is usually not advantageously placed when the top is even with the basement floor, and so that the melted stock runs direct¬ ly down into it, or the settling tank is on the basement floor and the steaming out is done on the first floor. In high buildings it may be preferable to steam out the stock on the top floor. THE LYE TANK. The size and number of lye tanks used must be adapted, of course to the requirements of the factory, as is also the manner of making the lye. It is usually best to have separate lye tanks for lye that is to be used in cold made and transparent soaps, as pure alkali, a different degree of strength, and perhaps the addi¬ tion of potash, are needed in this lye, so that it must be kept apart from the lye for the boiled soaps. The tanks are generally made cylindrical, and sometimes rectangular, of about % in. sheet iron, or sheet steel, and in most cases have a discharge pipe near the bottom, through which the lye runs off by its own gravity when the discharge cock is open¬ ed; this pipe is best arranged with a slight upward inclination, so that dirt cannot too easily run out, and is preferably 2 or 3 inches from the bottom; at the middle of the bottom is then placed a valve for washing out the sediment which collects from time to time. A steam pipe is also provided to introduce steam 90 The Soap Factory. for heating*, to dissolve the alkali, or when it is found desirable to accelerate the solution of the caustic in the water, (although with proper manipulation this aid is not really required, except to save time when in a hurry, or when poor grades of alkali are to be dissolved); ordinarily—with good grades of caustic—the heat which is developed spontaneously by the process of dissolv¬ ing the caustic is sufficient, if rightly managed. The tank should be large enough in diameter to admit one or more drums of alkali when placed in it crosswise. Such simple tanks as de¬ scribed are most ordinarily used for making the lye, the caustic being simply placed on the bottom and sufficient water run in to make lye of the desired strength. In some factories the drums Hg. o. are pounded with heavy hammers, to break up the caustic which is then thrown into the tanks, to be dissolved with the aid of steam. In some factories the iron drum is removed without break¬ ing up the caustic, and the latter is placed in solid blocks on the bottom of the tank as before mentioned; on running in water, if high-grade caustic is used, the latter dissolves without the aid of steam, and the lye near the bottom is very strong, becoming gradually weaker towards the top. By using a swing-joint pipe for drawing off the lye—similar to the pipe used for drawing the soap from the kettles—lye of different strength may be drawn from the same tank, by simply raising or lowering the inlet of this pipe. (See Figure 5.) Where smaller quantities of lye are made at one time the following plan may be found very con¬ venient: The drum, after removing only the heads, is suspended above the lye tank by an overhead differential pulley block, (Moore’s The Soap Factory. 91 patent and others), and lowered until it is just covered by the water contained in the tank. As fast as the lye forms it sinks t° th e bottom, forcing the fresh water up; the heat developed spontaneously aids in the solution, and as water or weak lye con- Fig. 6. tinues to be displaced by the stronger lye and to rise to the top, the caustic is soon dissolved. By making the lye in this man¬ ner, mechanical agitation, breaking up the caustic, and also the use of steam, are avoided, and the very little extra time required may be saved, if necessary, by using an extra tank at the same Fig. 7. time, or one large enough to admit a sufficient number of drums at a time. (See Fig. 6.) Instead of suspending the drums by a chain, a false bottom 92 The Soap Factory. or grate may be placed in the tank for the drums to rest on, or supports ma} 7 be laid across the sides of the tank on which the caustic is rolled, after removing- the iron drum. These supports may be connected by perforated sheet iron to prevent larg-e lumps of caustic falling- in while melting-. When this arrangement is used it is convenient to have the top of the tank even with the floor to facilitate rolling- on the caustic. (See Fig - . 7.) This arrangement, although exceedingly convenient, is not used SO'much as it deserves to be; in most factories the caustic is broken up by pounding the drum, and placed on the bottom of Fig. 8. the tank; water is then run in, and open steam introduced to ag¬ itate and rapidly heat the mass. In place of using steam to assist in dissolving caustic, the use of an air pump has been suggested, especially when there is use for such a machine for other purposes also. The advantage of this is—apart from greater safety—that the lye becomes less heated, which may be desirable at times, as when the lye is to be siphoned up to the storage tank. But, unless their is hurry, neither this nor steam will be required if the tank is properly arranged. Still another arrangement, which is not much used however, The Soap Factory. 93 consists of an ordinary tank into which a smaller perforated cylinder, or a wire netting-, has been set. The caustic is placed between the two cylinders and water admitted into the tank. A mechanical ag-itator which reaches into the water is then set in motion until all the caustic is dissolved. The object of the inner cylinder is to keep the lumps of caustic from interfering with the ag-itator blades. (See Fig-. 8.) If the lye made is to be used for cold-process soap, it may at times be necessary to have some provision made for cooling- it off rapidly, in order to save time. For this purpose a coil of pipe may be set into the tank, through which cold water may be cir¬ culated after all the caustic has been dissolved. When possible, however, it is much better to let the lye for cold made soap cool off slowly, so that the dirt settling to the bottom, and that ris¬ ing in the form of a scum, may be separated from it before use. Lye for the cold process requiring to be very caustic, it is also necessary to prevent it from absorbing carbonic acid from the atmosphere; to this end different devices are adopted. Prob¬ ably the simplest, and at the same time most effective method, is to place in the tank a quantity of mineral soap stock which will, as it does not saponify, always float on the surface of the ye and thus effectually exclude the air. Others cover the tank Cooling lye rapid, ly,for cold pro¬ cess. Settling lye. Means of preserv¬ ing lye for cold process. 94 The Soap Factory. Water connection with lye tank. as nearly air tight as possible, and perhaps place some quicklime on the top to absorb the carbonic acid from the surrounding atmosphere. This is objectionable, however, as it is rather in¬ efficient, and there is always the danger of some of the lime falling accidentally into the lye. A convenient arrangement on a l} r e tank is also a water pipe connected with the discharge pipe, as in the engraving, Fig. 9. Its object is to permit drawing off either water or lye, or both together, at pleasure, so that the pipe leading to the kettle will carry any desired strength of lye, from the strong lye in the tank down to simple water, according to how far the different valves are opened. The lye pipe might be given a short upward bend on issuing from the tank, which will have a tendency to prevent foreign matters, which have settled to the bottom, from going out. Although the lye tank should be placed higher than the kettle, so that the lye may run out of its own accord into the latter, circumstances at times require that the lye be raised to a higher level. For this purpose a cast iron steam-syphon or “ejector” is adapted, which works on the principle as herewith illustrated, and which by the injection of a current of steam The Soap Factory. 95 through the tapering tube creates a vacuum that forces the lye to rise into the hollow globe and then forces it upward through the outlet. With a steam pressure of 60 lbs. it will lift liquids 25 feet and elevate them about 15 feet above the ejector. Appar¬ atus of this kind are made by A. W. Cadman & Co., Hersey Mfg. Co., and others. Less convenient usuallv, but worth mention- ing, is the use for this purpose of an apparatus made on the plan of the stock blower to be described in the following pages. The outlet pipe from the lye tank to the kettle is sometimes made to terminate in a perforated piece, in such a manner that through the perforations the lye is distributed evenly over the kettle. Flanges, patches, and the like, are riveted on, but not bolted, as warm lye is apt to destroy such patching, as well as lead, tin, and the like, for which reason soldered utensils and lead pipe soon become leaky when used for lye. STRUNZ PATENT LYE APPARATUS. The manufacture in the soap factory, of caustic lye from soda ash by treatment with lime, was the universal practice be¬ fore caustic soda became an article of commerce; but the crude appliances used for the purpose were so inconvenient, that in course of time commercial caustic soda came into general use in this country. In the meantime, however, improvements have also been made in the apparatus and methods by which soda ash is made caustic by the soap maker, especially during the past several years. A number of very essential improvements have been made in this apparatus with the result of further simplify¬ ing the process to such an extent that the preparation of caustic lye from soda ash has become profitable even at a comparatively small difference between the price of soda ash and commercial caustic. The labor and other expense items, as well as the proportion of lime required having been reduced to a minimum. The accompanying illustration shows a L} T e Plant supplied with all the latest improvements. This plant has a capacity equivalent to 8 drums of 76% caustic per day. Although the profit on such a plant increases somewhat with the capacity, this process is profitable in cases even where the consumption of caustic lye does not exceed an equivalent of 150 drums per year. By this method the entire process is completed in a single operation with the least possible amount of lime; giving a yield 96 The Soap Factory. which is practically perfect. There is no driving-machinery to operate—no vacuum pumps and no air pumps to look after—in fact no other power is applied than that produced by direct steam from the boiler entering the apparatus. The proportion of lime required varies not only according to its purity but is also effected by the manner in which the process is conducted. The amount of lime now required for causticizing is much less than formerly. Exceptionally good grades now giving a satisfactory result in the proportion of from 63 to 65 lbs. of lime per 100 lbs. of soda ash. The lime must be well burned and as free from contamin¬ ation by magnesia as possible. In the apparatus illustrated on page 97 made by F. B. Strunz, Pittsburgh, Pa., the lye adhering to the lime-waste is practically all saved. The lime-waste is usually mixed with water and flushed away into the sewer. Attempts have been made to recausticize this lime-waste but the operation proved too expensive and could not compete with fresh lime which can be procured in most localities at $4.00 to $5.50 per ton. How¬ ever, where it is produced in sufficiently large quantities this lime waste would furnish excellent material for manufacturing The Soap Factory 97 Portland cement. For this purpose the lime-waste requires no preliminary treatment. In some cases this material can undoubt¬ edly be turned to value. Regarding - the cost of lye made by this process as compared costofiye. with that made by dissolving caustic soda, Mr. Strunz furnished in the American Soap Journal the following figures, which may be readily changed to suit different localities, etc.: “In Pittsburgh the saving amounts to about 1 ]/i cents per pound, figuring Pure Alkali at $1.42^2 for 48%: Caustic Soda Fig. 11 W/A/tt HEIN STRUNI'S - C O O ft O CO LYE APPARATUS *l*-&nAGOO/V Purs lim., liiH 1 m’s/;/»r-/wAvizz ill- 1 ./I l| 7 rnmim Wfi \ 14'JcjV QsT 11 77% at $3.08 for 60%, and freight on each at 15 cents per cwt. from New York. Lime is worth 20 cents per cwt., f.o.b. Pitts¬ burgh. 600 lbs. Caustic, 77%, at $3.08 for 60%.$23 72 Freight on 600 lbs. Caustic from New York to Pittsburgh 90 Labor, dissolving Caustic. ^ $24 77 98 The Soap Factory. “Caustic Lye Solution, equivalent to 600 lbs. Caustic Soda of 76%, is produced by: 800lbs. Soda Ash, 58%, $1.42)4 for 48% (at $1.72) .$13 76 Freight on 800 lbs. from New York to Pittsburgh, at 15 cents per cwt. 1 20 650 lbs. Lime, 20 cents per cwt. 1 30 Labor, preparing soda ash solution and adding Lime, 1)4 hours.23 cents Labor, removing lime waste from lve apparatus, 1 hour.15 cents 38—$16 64 Saving on 600 lbs. Caustic, 77%. $ 8 13 or, $1.35)4 per cwt. “In the East, where oyster shell lime can be procured at 13 cents per cwt., and on account of a slightly greater difference between the f.o.b. prices of Caustic and Soda Ash, the saving is somewhat more: Figuring $1.48 per cwt. of 77% Caustic, or very nearly 1 )4 cents per pound.” Under date of May 24, 1898, F. B. Strunz patented a kettle of special shape and with a particular arrangement of steam pipes and means for supplying the lime; the kettle and the apparatus described in the foregoing forming together a lye plant THE MELTING TROUGH. In smaller factories the tallow and other stock are often simply dug out of the barrels and placed in the kettle to melt. This entails more or less damage to the packages and consider¬ able work, for which reasons the melting of the stock by steam introduced into the barrels is much to be preferred. Melting has the further advantage of removing the fat more fully, an item which amounts to more than one might think, for in one case where the difference was investigated fully and systematically, it was found that a certain barrel filled with palm oil weighed 230 lbs. after all the stock had been carefully scraped out; on re¬ filling and later melting out the stock it weighed only 206 lbs. The 24 lbs. gained were oil that had soaked into the wood. A trough is used for this purpose, upon which the barrels are placed, and which receives the melted stock; it is made of sheet-iron or sheet steel, rectangular in form, and need not be more than about five inches high; it should incline slightly toward the outlet The Soap Factory. 99 above the settling- tank. The barrels are placed across the trough, or on timbers laid across the end pieces of the latter, with their open bung-holes downward. Pipes of ^-inch diame¬ ter are so arranged that steam can be turned into the barrels through the bungholes, either by having a separate pipe for each barrel, as shown in the accompanying engraving, or by a main pipe along the bottom of the trough, from which branches reach upward into the hogsheads or barrels, as indicated by the dotted lines in the same engraving just referred to. The ends of these branch pipes have an elbow joint, which turns easily, so that it may be introduced into the bunghole after the package has been properly placed. By admitting steam through the pipes the contents of the hogsheads are quickly emptied and can be run to the kettle or settling tank while still hot, thus saving most of the heat ex- Fig . 12. pended on the operation. A fine wire sieve should be placed in the trough where the discharge pipe is connected, so as to arrest chips of wood and coarse dirt, that would otherwise go into the kettle. Instead of a trough, a simple rack may be used to support the barrels for melting the stock. A convenient tool in this connection is a piece of board, two inches wide, and long enough to reach across the two pieces of timber that are placed lengthwise over the trough. Through this board, near one edge, are driven four or five very heavy nails, and the board is then nailed upon another, so as to prevent the nails from being pressed back again. These are used as blocking for the barrels, to prevent tipping over. , THE SETTLING TANK. From the melting apparatus the stock should be run to a set- o\ % i >>> * :> > > \ 100 The Soap Factory. tling tank, so that it may be properly settled and alsoexamined, instead of running- it directly into the kettle. These settling- tanks should be arranged with marks indicating- their capacity, so that the amount of stock placed in them or withdrawn from them may always be approximately calculated. ' In consideration of their great weig-ht, temperature, and conveniences, these tanks are frequently placed in the basement. THE STOCK BLOWER. Unless the melting- trough (or the settling tank) is so placed that the melted stock runs to the kettles by its own gravity, Fig. 13. some provision for conveying it there is required. This may be done by a pump or by a blower. The pump will be described hereafter. The stock blower, which is used in some factories for con¬ veying the fats from the settling tanks to the kettles, consists of a sheet-iron tank provided with a tight-fitting cover, and is test- ted for a pressure of at least 80 lbs. to the square inch. It has a The Soap Factory. 101 1% inch pipe (A) reaching' nearly to the bottom of the tank, for carrying- off the stock. B is a pipe for admitting- steam, the pres¬ sure of which forces the stock out of the tank. D is a pipe throug-h which the steam escapes from the empty blower when fresh stock runs in. E is a pipe from the stock tank. C is a valve throug-h which accumulated dirt may be blown out. A steam pipe should also be connected with pipe A for blowing- back, to clear it in case it becomes clog-g-ed by fat that may have become chilled. This apparatus may be improved for some uses by inserting- a dished false bottom (see small engraving-), with a hole in the centre. The dirt and water settling out from the stock (which may be kept warm by waste steam) would find its way below the false bottom and be prevented by the latter from going along with the stock on emptying the tank underpressure. An apparatus of this description may, under certain condi¬ tions, be of use to convey fluids other than fats, as for instance lye. THE SOAP KETTLE. In regard to soap kettles there are a great many variations, not alone in the actual requirements, but also in the opinions pre¬ vailing among practical soap boilers. In Europe the kettles or “pans” are still in many instances heated by fire, while the contents are stirred by hand, but this feature has been superseded in this country many years ago by the use of steam; it is therefore not necessary here to point out the many advantages which steam kettles have over the old-fash¬ ioned fire-heated affairs. Suffice it to say that the object of ap¬ plying heat to the ingredients in the soap kettle is twofold, name¬ ly not only to raise the fat and lye to a temperature favorable to the chemical reaction but also to produce the movement of the contents which, by thoroughly mixing them, contributes very largely to the process of saponification; it is hardly necessary to point out how much in this respect the introduction of open steam is superior to a fire heated kettle. Indeed, as shown in the cold process, a temperature far below boiling is sufficient to induce saponification, and with the use of open steam the reaction be¬ gins much earlier, as a result of the mechanical action of the steam, and at a comparatively low temperature. As to size, soap kettles range from a capacity of a few thou¬ sand pounds to those holding 150,000 lbs. of finished soap, and All kettles heated! by steam. Size of kettles. 102 The Soap Factory. more; the largest kettles still practical to use hold not much over 250,000 lbs. In shape the cylindrical form is the most common, square kettles being comparatively rare as they are in several re¬ spects inconvenient to use. As to dimensions, the proportion best adapted for good boiling is approximately 2 feet average width to 2/4 or 3 feet depth. Too deep a kettle in proportion to width is liable to cause boiling over and “jumping.” The walls of the kettles are either perpendicular or taper towards the bottom. A kettle of the latter kind, and the connections required for practical working, are illustrated by the accompanying Fig. 15, which represents one of the kettles used in the factor} 7 of Messrs. A. Melzer & Co., of Evansville, Ind., as described by them in the American Soap Journal , as follows: “The dimensions of this kettle are: Depth 15 feet; diameter across top, 15 feet; diameter across bottom, 10 feet; capacity, 60,- 000 pounds Settled Soap. Bottom of kettle is made of % inch flange iron dished 12 inches. The first 4 feet of sides of kettle are made of % inch iron, the balance 3-16 inch; seams vertical. Fig. 14. To center of bottom is riveted a heavy cast-iron pouch (Fig. 14), tapped for two 2)4-inch pipes, one for running out the spent lye, and the other, which is at right angels to the first, for running out the nigre into a receptacle for that purpose, preparatory to pumping it into other kettles. This latter pipe may be connect¬ ed direct with a rotary pump, but in this case there would be liability of sand and nails getting into the pump, which might cause much trouble. Both these discharge pipes are supplied with a half-inch steam pipe for clearing them of cold soap, sticks and other obstructions that may have lodged therein. The steam Fig. 15.—SOAP KETTLE. (See page 102.) THE NEW FRENCH SYSTEM OF MILLING. (See pages 169 and 17U.) The Soap Factory. 103 pipes that feed the coils in the kettles enter through cast-iron flanges and an extra 34 inch wrought plate riveted on side of the kettle just above the bottom. Each kettle is supplied with a gen¬ eral steam valve, which shuts off the steam on all the coils; a valve for each, the open and closed coils, and a small valve or pet cock for draining the pipes and to let escape freely any steam which may pass the main valve, and thus prevent any possibility of it getting into the kettle at a time when it is not wanted there. These valves can all be operated by means of iron rods conveni¬ ently located at the kettles in the boiling room. The pouch on bottom of the kettle is covered over by a grating made of % inch wire and having 34 inch meshes for the purpose of preventing bungs or tools that may have found their way into the kettle from obstructing the discharge pipes. The open steam coil is a single 36 inch ring, made of extra strong 1% inch pipe and per¬ forated with a sufficient number of inch holes. The closed steam coil is a flat spiral, containing 350 feet of continuous 1% inch extra strong pipe. This form of coils we have found the most practical, after trying a variety. “The finished soap is discharged through a 3-inch pipe that enters the kettle just above the steam pipes. On inside of kettle this pipe is about 6 feet long and at the lower end is provided with two elbows which form a hinge, so that the pipe may be swung over and gradually lowered to a point just above the nigre. When soap is all out this pipe is drawn back to a vertical posi¬ tion by means of the chain attached to its top, and the mouth of pipe is closed with a cap attached to a 34 inch iron rod, with a “T” handle, that reaches to the top of the kettle. “Running across top of the kettle is a shaft, for which 1^ inch extra strong pipe will answer, and mounted thereon is a reel or paddle wheel as shown in Fig. 16, page 104. . “The arms or spokes of this reel are made of yi x 1*4 inch iron and are 16 inches long from center of shaft to end of the arms; the blades, four in number, are }£ x 4 x 24 inches, and we find this size reel amply sufficient to hold down the soap. In our factory these reels are driven by a small special engine, which also drives the fans for keeping the air in motion in the Boiling Room; they require little power, and the work performed by them as compared to the work of a paddle or shovel in the hands of a man, is like the work of a steamboat wheel and that of a boat Arrangement for preventing boil¬ ing over. 104 The Soap Factory. oar. This apparatus has been in use in some factories of our country for many years. “To prevent the soap from cooling* too rapidly around the sides of the kettle, this is jacketed from the bottom to the floor above, with 2-inch wooden staves, and to prevent the heat and Fisr- 10. steam of the kettle from filling the Boiling* Room to the discomfort of those employed therein, the kettle is encased from its top to the floor next above. On this floor the rosin is broken up and through a chute is conducted into the kettle. By this arrange¬ ment two men can easily do the work of four that have to shovel the rosin over the side of the kettle, and all rosin dust is kept out of the Boiling Room. From rosin floor to the roof and a few feet above, a suitable chute (ours are made of sheet iron and are 5 feet in diameter) carries the steam out of doors. This chute is provided with a cut-off or damper to prevent the cold air in win¬ ter from descending into the kettle when not a-boiling. “The fats, lye, water or brine run into this kettle through a system of pipes under the control of the soap boiler or attend¬ ant, and the finished soap runs out through the 3-inch pipe men¬ tioned above. The time required for framing a 50,000 to 60,- 000 lbs. patch is from three to four hours.” The next illustration (Fig. 17) is a sectional view of a ket¬ tle, arranged somewhat similarly, but having vertical walls, and the closed steam pipe arranged “criss-cross” instead of spirally. This pipe is less expensive and for not too large kettles just as effective as a spiral coil; it covers the bottom of the kettle to within about a foot of the walls, the space left free being required for convenience in cleaning. For larger kettles this pipe has the The Soap Factory. 105 disadvantage that the hottest steam is all on one side of the ket¬ tle, and the boiling thereby apt to be uneven. The open steam coil has a diameter about # that of the bottom of the kettle; its perforations are similar as already described, their total area not to exceed the capacity of the pipe. The valves for opening and Fig. 17. turning off the steam in the pipes are placed (in both kettles shown) near the bottom of the kettles, so that on turning off the open steam the condensing steam in the pipe will not, by creat¬ ing a partial vacuum, cause the soap to be forced up into the pipe 106 The Soap Factory. and choke it on cooling". In other factories, again, the steam pipes enter the kettles from above, passing - over at the rim and running to the bottom of the kettle along the inside wall; thus the pipe does not need to perforate the kettle wall, but in this case the valves cannot be so conveniently placed as just described. Both, the open and the closed pipe are 1 to \% inch for a kettle of 60—80,000 lbs. capacity. The soap outlet pipe has already been described, and is shown in the last illustration as entering the kettle at a point above the “nigre” or dark soap. Its inlet is turned upward, which facilitates drawing off the soap from the nigre. Others prefer this opening turned downward, so that it can be used to draw the soap from an iron bucket sunk into the contents of the kettle, in such a manner that it may be conveni¬ ently employed to draw the last of the clean soap off from the “nigre” underneath, the soap being collected in the bucket and drawn off through the pipe. When not in use the inlet of the pipe is closed, as described before; a strainer may also be pro¬ vided on the inlet, to prevent sticks or dirt from entering which might become lodged in the elbow joint of the pipe. In the case of boiled-down soap such as “German Motted,” which is very thick and not only difficult and slow to pump, but also liable to become frothy through pumping, some factories use a separate 5 or 6 inch valve in the side of the kettle, connected with a pipe in such a manner that a large funnel can be inserted through which the last soap can be dipped out. The crutcher is then most conveniently placed near the bottom of. the kettle. Instead of the single valve shown on the outlet at the bottom of the kettle, two valves may be placed to advantage, one below the other as shown in the illustration above. The Soap Factory. 107 This arrangement not only provides against accident in case the single valve fails to close for any reason, but, by con¬ necting a steam pipe between the two valves, any soap that may clog the lye outlet may be blown back; the kettle may even be temporarily heated by this steam connection, in case the open steam coil should have become clogged up by chilled soap. lig. 11). Fig. 19 represents a similar kettle as made by the Hersey Mfg. Co., of sheet steel and heavy angle iron around the top to make it rigid; the cast iron supporting pieces can be attached at any point ordered. Some years ago a steam coil was adopted in many factories ^^eau/cons which, instead of over the bottom, was placed close to the walls 108 The Soap Factory. Mechanical 1 ig. ‘20. A convenient and effect : ve combination of the several coils mentioned is illustrated by Figure 21, page 109, Farrell & Rempe Co., of Chicago, manufacture these coils. Thirty years ago mechanical stirrers were frequently used of the kettle, running spirally along their inner surface for two or three feet in height. This form of coil was, however, soon abandoned again in most factories, as the low coil near the bot¬ tom has the advantage of being mostly immersed in lye and thus keeping the soap from sticking to it; the high coil did not have this advantage, and, furthermore, the hot steam entering on the top cools off so much before reaching the bottom of the kettle, that in large kettles sometimes only the upper part of the contents, and that near the walls of the kettle, could be made to boil. The latter difficulty, however, could be at least partly avoided by running the steam pipe down almost to the bottom and then coil¬ ing it upward. In order to secure an even boiling throughout the kettle, the best plan is undoubtedly to have the closed coil placed flat over the bottom of the kettle, running it in the centre first—so that the hottest steam is in the middle—and then coil¬ ing it around to gradually approach the walls of the kettle, as shown in the next engraving. rers. The Soap Factory. 109 to help stir the contents of the kettles. They have since been discontinued in nearly all cases, but at times they are quite con¬ venient to have, and may yet come into use again for the smaller kettles more than they are at present. In regard to the use of steam, it may also be mentioned that Open vs. closed while both open and closed steam are found desirable by the great steam ' majority of manufacturers, there are those who advocate the use Fig. 21. of open steam only, arguing that the closed steam pipe is a relic of the days when impure caustic made the use of weak lyes neces¬ sary, in consequence of which the excess of water present makes the further addition of water from the open steam undesirable, that now the use of purer caustic permitting the use of strong lye, there is no need for closed coils. There are also those who even believe that closed steam is all-sufficient, but these are mat¬ ters which will probably never be settled to the satisfaction of all. One thing to guard against is too great number of holes in the open steam pipe, as this leads to insufficient boiling on one side of the kettle, and in several cases an uneven product of soap in consequence, the feed pipe being unable to supply steam to all the perforation. The steam is used at a pressure of 3 to 4 at- PresMlveolsteam mospheres (one atmosphere = 15 lb?.) Super-heated steam, as sometimes recommended, is hardly used. If much water is to be 110 The Soap Factory. Jacketed kettles. * •y* evaporated from a soap, a pressure of 5 atmospheres is quite suf¬ ficient. The steam, which has spent most of its heat while passing through the closed coil, is condensed into hot water on issuing from the coil, and can be used to advantage for various purposes, as for dissolving caustic, thus utilizing the heat it contains and also taking advantage of the purity of the distilled water. It still remains to mention the jacketed kettles, with double walls at the lower part, between which steam circulates. This arrangement is not adapted for large kettles, nor indeed very practical in any ordinary case where a soap is to be boiled, as the dirt accumulating on the bottom prevents the heat from being properly effective. When used, the bottom should not be rounded too much, but be flat and the jacket should not extend too far up, as otherwise the soap might boil in the upper part of the ket¬ tle only, and not at the bottom. If the fats are previously well clarified, for making fine toilet soaps, these kettles have the advantage that they can be cleaned more thoroughly, and that there are no steam pipes at the bottom between which undissolved Fig. 22. salt or strong lye might remain in spite of all boiling; in this The Soap Factory. Ill case also there is no danger of wasting heat by accumulated dirt at the bottom. Dopp's Jacketed Toilet Soap Kettle: Within the C suspended above the kettle (see Fig. 22) there runs a conveyor-screw D resembling the screw in some crutcners described further on, which is very effective for mixing or “crutching” the contents of the kettle. The agitator is easily taken apart for cleaning purposes, by simply loosening a set-screw, and may be raised and lowered at will, as well as swung out of the way when not in use. For some purposes, notably in making half-boiled soaps, it is convenient to connect the steam pipe with a cold water pipe, in the manner shown in the accompanying drawing. This ar¬ rangement permits of rapidly reducing the temperature of the contents, if this should be necessary to prevent boiling over, or when the stock to be used is too hot. CONNECTIONS WITH KETTLES. In the matter of facilities for charging and emptying the kettles, regard must of course be had to the peculiarities of the factory and the soap to be made. A soap pump being a practi¬ cally indispensable machine around the factory, it is a good plan to connect the same with all the soap and lye outlet pipes, and to run the discharge pipes of the pump to all the other kettles tanks used in connection with them. In this manner all possible contingencies for the disposal of the contents of the kettles are provided for. In making these connections it is well, however, to bear in mind the possibility of small leaks in one of 112 The Soap Factory. V laci pum p the lye valves, which might cause lye to find its way into the soap being pumped and render it surprisingly “strong.” The pipes leading to the pump ought to have a valve near the tank, and one near the pump. So that no stock lye, soap, &c., can run into the pipe when pumping from other tanks. THE SOAP PUMP. Among the various pumps that have been constructed for the purposes of the soap factory, such as pumping grease to the kettles, pumping the soap to the crutcher, bringing lye to the kettles, &c. The Heksey pump (Fig. 24, 25, 26, 27,) the Taber pump (Fig. 28,) and the Johnson Rotary Pump, have come into wide use. Fig. 24. The Hersey pump is set up in any convenient position, not more than ten feet above the bottom of the kettles, but preferab¬ ly below the kettle, so that the soap flows into the pump by its own weight instead of requiring the pump to draw it upward. It is connected with the kettles, etc., as already described; and its discharge side should be connected with a steam pipe for oc¬ casional blowing back and cleaning. (A water pipe may be con¬ venient in connection with some pumps also, for the purpose of priming the pump in case it refuses to work, as may occur when the body to be pumped is so warm as to give off vapor which des¬ troys the vacuum). Valves are placed in the connecting pipes The Soap Factory. 113 so that the pump can draw from and discharge into any of the kettles and tanks without disturbing the others. The special feature of this pump is that it conveys not only soap, but also hot as well as cold oils, lye of every description, and water. With a speed of 120 revolutions per minute, the three sizes have a capacity 3,000, 6,000 and 10,000 gallons per hour, respectively. The blade B swings on a pivot, and the cone-shaped piece D, by its contact with the cover, maintains a division between the two sides, so that in sweeping around the blade B, running in the Fig. ‘25. direction of the arrow, draws the soap in at A and discharges it at C, emptying the pump twice in each revolution. The opening marked A in the sectionial view is the suction when the pump is run in the direction of the arrow; on reversing the machine the same opening becomes the discharge, and the opposite opening will then be the suction. The outlets are 2 to 3 inches in diameter, according to size of pump, and correspond to the size of the discharge pipes of the kettles as generally used. In connection with the pump should be a belt-shifter so ar¬ ranged that it can be operated by means of a rope from any floor of the factory. Fig. 27 shows above pump combined with engine. The latter is provided with a pulley from which any other piece of machinery can be driven. Working on a different principle, but also very effective are the Taber soap pump shown in Fig. 28; the Johnson Rotary Pump, Fig. 29, 30, 31; and that made by Brown & Patterson, Fig. 32. For soap factories these pumps are made of iron, but steel or bronze pumps for special purposes are made by the same firms. In the foregoing pages has been described the machinery 114 The Soap Factory The Soap Factory. 115 required for converting- fat and alkalies into soap; but there still remains to be considered a number of machines and appli- Fig. 27. ances necessary to form the bulk soap contained in the kettle into a merchantable bar or cake. Prominent among these are 116 The Soap Factory. Cleaning the Crutcher. Crntcbingair into •soap. THE CRUTCHER AND THE REMELTER. The name “crutcher” is derived from the old fashioned crutch-like stirrer which was in use before machinery took its place, and as the old hand crutch was—and to some extent still is—employed for several uses, so the machines now serve a variety of purposes; all these uses, however, are based on its action as a mixer or as agitator. In size these machines correspond with the capacity of the “frames” to be described later, which ordinarily hold about 1,200 lbs. A few minutes agitation in the crutcher suffices to thorough¬ ly mix a batch of soap with the ingredients added, and the con¬ tents are then emptied into the “frame,” for which purpose the crutcher is so placed that the soap can run directly into the frames placed underneath. Immediately after emptying, these machines may be cleaned by running through them boiling hot water, or filling them with water and bringing it to a boil by an open steam pipe, or by letting open steam through the covered apparatus; but if the soap is allowed to get cold in them, the cleaning operation is more difficult and tedious. It should be noticed that some styles of crutchers are made either with or without a steam jacket. While it is not generally required for simply mixing soap with the filling, the steam jacket is often a desirable feature, as when the machine is to be used as a remelter for scrap soap; or when the soap has cooled off too far before crutching; or for making soap by the cold or half- boiled process. In the following are described the principal styles of crutch¬ ers as well as remelters in use. As some of these machines serve for both purposes, they cannot well be considered separately. The machines described are all admirably adapted for their purpose, and are preferred according to individual requirements or per¬ sonal preference. In a general way it may be said that some crutchers have a stronger tendency than others to crutch air into the soap, and this may often lead to decide a choice between the different styles. Air crutched into soap brightens its color, but at the same time makes it more dull and opaque. Doll’s Crutcher is one of the simplest forms of this ma¬ chine. It consists of a simple tank, having a soap outlet at the bottom. Within it is placed a cylinder, open on top and bottom, The Soap Factory. 117 resting - on leg’s. In this cylinder runs a screw, as shown in sev¬ eral illustrations hereafter, which catches the soap at the bottom of the apparatus and carries it to the top of the inner cylinder, o^er whose rim it falls back into the space between the inner and outer cylinders, to find its way gradually to the bottom Fig. 33. ag-ain. This mixer is designed especially for mixing the soap, while still warm and soft, with “filling,” such as sal soda, silicate, etc. A modification of the apparatus is shown above, the object of which is not only to mix the soap and filling, but also to re¬ melt the scraps and cuttings of soap on hand, that require work¬ ing over to be salable; or to manufacture soap by the cold pro¬ cess and remelted toilet soaps. In this apparatus the inner cy¬ linder ( A ) is jacketed, and the legs (2?) supporting it are made of gas pipe, through which steam may be admitted to the jacket. Open steam may also be turned directly into the soap by means of a single perforated coil near the bottom of the mixer. As the scraps of soap are carried upward by the screw they are thus heated by the open and closed steam until they become soft enough to be forced through the sieve placed above the cylinder. 118 The Soap Factory. The sieve consists of two halves which are held in position by the arms E , and is readily removable. The driving- parts of the machine are so arrang-ed that they can be quickly reversed, to facilitate emptying- the crutcher. This machine, plain or with remelting- apparatus attached, Fig. 34. is also made (single or double) connected on one frame with a steam engine, as shown on illustration herewith. Atkiss’ Mixer. The principle of mixing- soap by this ma¬ chine is evident by a glance at the illustration. The wing-s on the central shaft, as shown, have a slanting- position, and in ad¬ dition are raised and lowered as indicated by the dotted lines. (Fig-. 35.) Strunz’ Crutcher. The interior view of this machine also explains itself. Soap is run in until the wing-s are one or two inches more than completely covered and the crutcher is set in motion in the direction required to work the soap toward the outlet, the central shaft making- 45 to 50 revolutions per minute. While emptying- the contents into the frame, the paddles should not be running-, unless the soap runs out very slowly. This style of crutcher is also made with a steam jacket, as The Soap Factory. Fig. 36.—Outside View of Machine. 119 120 The Soap Factory shown in the next illustration. The direction of the steam or water, as the case may be, as it circulates through the machine, Fif. 38.—Jacket View of Machine The Soap Factory 121 is indicated by the arrows ; also the pipe through which they escape. The valve at the bottom is for the purpose of drawing* off the water left in the jacket at the end of the operation, which should never be overlooked, as its presence would cause a strain on admitting* steam, or in cold weather even freezing* and burst- ing* of the jacket. To clean the machine when necessary, a few pailfuls of salt water at 22° are added, and the machine set into motion for a few minutes. The escape steam pipe of the jacketed machine should be left free, that is to say, it should have no valve attached to it. Recently F. B. Strunz of Pittsburgh, Pa., has iitroduced an 122 The Soap Factory improved Strunz crutcher which cools and heats the contents quickly, as desired, and in which it is impossible for any of the paddles to become detached or break off. It works thoroughly and rapidly and allows no air to mix with the soap if the mach¬ ine is filled above the top of the paddles, the soap coming out particularly clear; when filled to within a few inches from the top of the paddles, the soap quickly becomes aerated up to the point of floating. Highly filled soaps and mineral scouring soap even can thus be made light enough to float. Houchin & Huber’s Crutcher. This machine consists of an outer shell made of two shells of boiler steel riveted together, Fig. 40. The Soap Factory. 123 so as to form a steam jacket, which extends over the whole bot¬ tom and up the whole side of the machine. An inner drum of like construction, except that it is open top and bottom, a con¬ veyor screw to carry contents up inner cylinder and over and a means for operating- same with overhead shaft and g-earing-, in tvym operated by an engine of modern construction. Owing- to the peculiar construction of the outer shell, the heating- capacity of the same is very large, much more so than any machine so far designed and being constructed like a boiler and thoroughly stay-bolted cannot burst under ordinary steam pressures. Being wrought steel and no thicker than required, can also be cooled much quicker in operation than where a large amount of cast iron need be cooled. The shell can never crack in cold weather, like cast iron and as a drip is provided in the exact center or lowest part of the bottom, will drain itself perfectly at any time. Dopp’s Crutcher and Remelter. This apparatus is made in FijLr. 41. 124 The Soap Factory two styles, that is to say, it is arranged either with or without a steam engine of its own. While, therefore, in the latter case the machine is driven by a special shaft and belt, the one with an engine of its own not only works independently from all other machines in the factory, but can be used in addition to transmit power (while the crutcher is either running or standing still) to run the elevator, or the soap pump, or such other machinery as may be in the factory. This crutcher and remelter consists of a steam jacket and an inner shell, cast together in one piece, and having a large outlet in the center of the bottom for discharging the contents. The Soap Factory. 125 In the center of the kettle is placed a steam heating - radiator formed by a system of vertical pipes arranged cylindrically, and with open spaces between them; steam passes through this radi¬ ator into the jacketed part of the kettle, but can be cut off so that only the inner cylinder has steam. A conveyor screw is placed in the center of this radiator for mixing the soap. When the machine is to be used for remelting, it is filled with soap scraps, covered up, and the steam at a pressure of about 20 lbs. is turned on; too high pressure may scorch the soap. As soon as a portion of the soap is melted the screw is set in motion. Open steam may also be turned into the soap to moisten it, if necessary. The motion of the screw lifts the soap and throws it over the the top of the radiator and partly forces it through the open spaces between the pipes. The pieces that are too large to pass in this manner are carried up and wedged in between the open ports, formed by the upper ends of the steam pipes. By the motion of the screw the pieces are sheared off and thus completely cut up. When required for cooling, cold water may be passed, in¬ stead of steam, into the jacket and the radiator. The screw may be run forward or backward, the change being effected by simply shifting the gearing. If it is found that the soap has a tendency to become spongy while lying in the hot jacket, steam to the latter must be shut off. The engine connected with the crutcher, as shown in Fig. 42, is one of eight horse-power, and is, therefore, sufficient not only to drive the machine, but run an elevator, and pump soap at the same time, (or do the latter work alone while the crutcher is not in motion). It dispenses with all shafting, pulleys and belting for crutching, and may consequently be set up in any place desired. All that is necessary is to connect the machine to a boiler having 40 lbs. or more of steam. It is an extremely convenient apparatus, not only for remelt¬ ing, but also for mixing and for making soaps by the cold process. Whitaker’s Remelter. This is a machine specially design¬ ed for the remelting of soap, whether for working up scraps or for making remelted toilet soaps. It consists of the wrought iron cylinder A into which is set the continuous steam pipe B connecting with the horizontal pipe b. These pipes rest on a wire netting through which the melted soap may drain off. F 126 The Soap Factory. is a perforated pipe for admitting- steam into the soap throug-h the valve /. The condensed steam is drawn off by pipe/. When the apparatus is filled with soap it is covered, and open steam turned on. When the scraps begin to melt, the open steam is shut off, the condensed steam drained off, and closed steam turned on. The melted soap is drawn into the frames as it melts and occasionally crutched through; or the soap is run from the remelter into the crutcher and there worked through before framing. The time required for the operation depends on the dryness Accelerating the ^ scra p S f or the more water the soap contains the more melting. ... r quickly will it melt. Ten to twenty frames of soap scrap can be remelted in a day by this machine, when used as described. In large factories where there is considerable work for the remelter, it is a good plan to provide it with a high “curb” into which the scraps are thrown as fast as they come from the cutting ma¬ chinery. The pressure of the great amount of scraps above serves to press the remelted soap out quickly, thereb}Mncreasing . the capacity of the remelter considerably and improving the pro- The Soap Factory. 127 duct. At the same time the curb, if properly arranged, will pre¬ vent the rapid drying of the scrap, which circumstance also in¬ creases the capacity for remelting. Lastly, the curb may pass through several stories, with doors through which the scraps may be thrown into the remelter, whereby work in handling them is saved. THE SAL SODA TANK. As “sal soda” filling is now very generally made from soda ash, it is well to remember that soda ash is more soluble in water at 100 u than it is in boiling water; it is therefore sufficient to have the water at 80° when the soda ash is put in. To facili¬ tate solution by means of agitation, if there is an air pump in the factory, the sal soda tank ma} r be connected with it. The process of dissolving raises the temperature of the water consid¬ erably, but by making the solution in the manner here indicated it will have the right temperature for use as soon as it is strong enough and has settled out the impurities. To prevent boiling over when made in the ordinary way, the tank should not be high and narrow but rather low and wide. The steam (or air) pipe somewhat resembles the open steam pipe as described in connec¬ tion with the soap kettle, and should have the perforations at the sides of the pipe (instead of on top) so as to keep the soda ash from settling down to the bottom of the tank as it would if the holes faced upward. In this case also, the capacity of the perforations should not exceed that of the pipe itself, in order that an even pressure may be forced through each hole, and the solution should also be drawn off two to four inches above the bottom so as to keep the sediment out. The valve should be a double-gated one, as it sometimes happens in winter that the sal soda crystallizes in the pipes and it may become necessary to heat it or drive a rod through the pipe; another way of obviating this difficulty is to use a double-jointed draw-off pipe in the tank like that used in the soap kettle. SOAP FRAiTES. When the soap is finished in the kettle, and has received the required additions in the crutcher, it is run into the soap “frames” for cooling and hardening. These frames are made either of wood or of iron, the latter being the kind most generally used in Wood and frames. Iron 128 The Soap Factory. this country. Wooden frames, which are considerably lighter and therefore easier to handle, naturally retard the cooling of the soap, and are therefore mostly used for special kinds of soap which require slow cooling. The iron frame, as generally used for common laundry soap, is in most cases of a size holding about 1,200 lbs. Whitaker’s Patent Soap Frame has a wooden bottom mounted upon truck wheels for moving it about the factory, and two sides of sheet iron, flanged at their upper edges, and strengthened by ribs of corrugated sheet iron running in the direction of their length on the outer surface; this device pre¬ vents the sides from twisting or bending, so that the soap will Fig. U. set in the exact rectangular shape, on cooling. The sides are The Soap Factory. 129 connected by ends of two inch plank and secured by clamps, allowing-of mounting- and dismounting- the frame almost instantly. In such iron frames ordinary soap cools sufficiently to strip in from 24 to 48 hours, according- to the weather and temperature of framing-. The averag-e size of this frame weig-hs about 370 lbs. The frames are made to order, in every size and shape desired. When so ordered these frames are made water-tight with rubber packing, for special use. Dopp’s Soap Frame. The illustration of this frame explains itself. HoucHin & Huber’s Soap Frame. (Fig. 45.) This frame has quick acting adjustable end clamps. These clamps may be taken up in an instant, without a wrench or tool of any kind. Fig 1 . 45. So if an end does not clamp tightly, a single turn of this device will generally suffice to make a tight frame. A patent nas been applied for. 130 The Soap Factory. Home-made Frames: A cheap, convenient, and easily handled, as well as quickly cooling-frame may be made according to the following- description, given by a writer in the American Soap Journal. The sizes mentioned are for a frame holding- 1,200 lbs. of soap. Fisjr. 40. Fig. 47. Fig-. 46 shows the frame ready for use, but empt}-, the sides being: of steel of No. 12 thickness and the ends of wood. The o sides have lj4 inch angde irons, running- lengthwise, three in number, to strengthen them, and also at each end perpendicularly a tapering angle on which clamps work, to bring the sides up The Soap Factory 131 rigidly when the clamps are driven down upon the tapering angle irons, which near the bottom assumes its full size of 1J4 inches in width. On one end of the frame is partly shown a com¬ bined wood and iron clamp, one of a pair used only when running the frame away from the crutcher, on and off elevators, and over rough floors while the soap in the frame is still hot. Fig. 49. Fig. 50. In this cut is seen one of the center wheels, 9 inches in diam¬ eter, on which the frame principally rests; at each end, not dis¬ tinctly shown in the cut, is a pair of inch wheels, hung to¬ gether on a swivel, in the form of a castor, which failing to more than barely touch the floor lightly, if at all, enables the frame to be easily and quickly revolved on its axle. The end pieces are simply wooden planks, say inch thick with one inch battens as shown. For convenience in every way a frame of the capacity 132 The Soap Factory. stated may be made, inside measures, say 54 inches in length, 40 inches in depth, and 14% inches in width, and in making out specifications for the iron work allowance, of course, must be made in addition to these figures for the thickness of wooden- ends, say 5 inches, and for a false bottom of say one inch. One inch axels of steel should be used for the wheels. Fig. 47 shows the steel side, removed from the frame. This should be made straight and flat. Fig. 48 shows the frame bottom, top view, which needs no further explanation, as the cut speaks for itself. Fig. 49 shows the reverse of the same. The bottom may be made of 2 inch plank, 5 feet 3 inches long, 20 inches wide, with say four battens on under side, 2x4 inches, and with wheels placed as shown. Fig. 48 shows cleats 2% inches in width and a false bottom 54 x 14% inches, and one inch thick, placed relatively with spaces for receiving and retaining in position the sides and ends. Fig. 50 shows the steel clamps, one somewhat shorter than the other, at each end of the frame, 2 x % inch, curved at ends to fit upon the tapering angle iron on frame sides to hold the whole rigidly in position. It also shows the wood and iron clamp for temporary use, as before referred to. The iron castors can be obtained through any large hardware house. The iron center wheels should be made light, but strong, say of two inch face. . Constructed of steel not unnecessarily thick, these frames are readily taken apart and set up again by even two boys, and when filled with soap they can be easily moved about on a smooth floor, and can be turned completely around within the space of their own length by one boy alone. When set up, the clamps hold them together very rigidly, making a very strong frame. Track for the frames Extra bottoms In factories where many frames are used, it is convenient to have a track on which fit the wheels of the frame, so that the soap can be easily wheeled from one room into the other. In this case it may be best to have the wheels so placed on the bot¬ tom of the frame that the latter stands crosswise on the track. The size of a 1,000 lbs. frame being about 14 x 56 inches, (and about 40 inches high) much space on the track is saved by hav¬ ing the wheels placed in this manner. It is also found convenient to have one extra bottom for each The Soap Factory. 133 frame, for while one bottom is occupied by the block of soap after it has been “stripped,” the extra bottom, together with the sides and end pieces taken from the first bottom, can be used for the next framing. Where frames are used that have no wheels, they are placed below the crutcher on “run ways,,’ in such a manner that the frame stands high enough above the floor to readily permit of pushing a truck or ‘‘buggy” underneath them. This buggy is made of iron and so constructed that, on raising the handle, its frame work is raised sufficiently to lift the soap frame off the run ways. On wheeling the truck to another part of the factory and lowering the handle, the frame is also lowered and placed on similar run ways provided for the purpose near the cutting machinery. Fig. 51. Instead of the “run ways,” and the special truck described, another contrivance is used in some places which consists of a number of pieces of gas-pipe, through which rods are passed to serve as axels for the pipes which in turn are used as wheels. The axels are placed parallel to each other and their ends se¬ cured in a frame-work. The frame bottoms are slightly curved, so that this apparatus can be easily slipped under them. While the iron frames, as said before, are those generally used for most soaps, some manufacturers still prefer the wooden ones as, on account of their light weight, they are easy to handle; nor do they become rusty and stain the soap, but on the contrary become covered after a short use, on their inner surface, by a glossy enamel-like coating, and therefore strip easily. For quite small frames, such as are used to advantage for some cold-made soaps, a cast iron box is well adapted, which is cut in half through the sides and bottom. For setting it up, it is only necessary to place the two halves together and secure them by a clamp. Trucks. Wooden frames. Small cast iron frames. 134 The Soap Factory. THE SOAP SLABBER AND CUTTER. The block of soap left on the bottom of the frames after stripping* is cut into marketable sizes by means of wire. The manner in which this operation was first performed was by mark¬ ing the block where it was intended to be cut, and simply draw¬ ing a wire through it along these marks. In some factories this simple process is still employed, but for large factories a Fig. 52. machine, somewhat on the plan shown herewith, will be practically indispensable on account of the saving in time and labor eff¬ ected by it. The illustration (Fig. 52, made by the Hersey Mfg. Co., and known as the “Ralston Slabber”) shows how the wires cut the block into slabs in an exceedingly short time and with the greatest possible regularity. The slabber should have a size corresponding as closely as possible to that of the frames, so that the cutting wires are just long enough to cut the block of soap; The Soap Factory. 135 too long- wires are apt to break, owing- to the greater tension required to keep them in a straight position. The machine is mounted on wheels, so that it may be readily moved from one frame of soap to another. For slabs of varying thickness it is most convenient to have extra “reeds” which can be readily changed. As these machines, to give the greatest satisfaction, should correspond in size to the frames, it is necessary to have regard in their construction to the following measures; inside •) length, width and depth of frames, diameter of frame wheels, length of axle, and of course thickness of slabs to be cut. Another slabber is shown in Fig. 53, and is made by Brown & Patterson. Another slabber is made by Houchin & Huber. See Fig. 54. Fig. 55 is a rough sketch of the principle on which a home¬ made slabber may be constructed. For cutting the slabs up into long bars and into cakes, machines of various construction are used, as may be best adapted 136 The Soap Factory to the requirements of the factor} 7 . The accompanying' Fig - . 56 and 57 hardly require further description, the mechanical de¬ tails appearing - plainly; nor can we describe all the forms of this machine in use, since they are frequently made accordidg to order, to comply ^ith individual needs and preferences. Fig. 54. Fig. 58 shows a soap cutter made by the Hersey Mfg. Co., of Boston. This machine cuts the slabs first into long bars and then into cakes, and then delivers them upon the “spreading” arrangement. Parallell staves are generally provided (see illustration) for the bars of soap to slide on after being cut; this arrangement is called a “spreader,” as by drawing the staves endwise the bars The Soap Factory 137 are spread slightly apart, in order to facilitate drying- on the rack, by allowing- the air to circulate freely among- the bars. An attachment for stamping- the cakes (if they are not to be pressed) may also be applied to this machine. Fig-. 50. According- to the needs of the factory, this machine is fur¬ nished with either adjustable wire holders for cutting- different sizes of bars and cakes, or separate reeds for the different sizes are kept on hand. Fig*. 57 represents a set of iron cutting- frames, as made by 138 The Soap Factory The Soap Factory. 139 H. Wm. Dopp& Son, of Buffalo. These frames are made of cast iron, and the wires are fastened and spaced as desired by means of thumb-screws. The frames are fastened by bolts upon a wooden frame as shown, and wooden bed plates must be provided for on the latter, as shown in the small engraving 1 forming part of the same figure. Fig. 59. As will be seen, the preceding machinery is run by hand, but there have also been made a few machines after a special pattern shown herewith, operated by steam power. (See Fig-. 59.) This machine slabs, cuts, racks, and spreads an enormous amount of soap per day. Another slabber and caking machine has recently been de¬ vised by Christopher Lipps of Baltimore, and still another set by Curtis Davis & Co. of Cambridgeport, but we have not room to illustrate them all. The wire used in these cutting machines is what is known 140 The Soap Factory. Planing thecalces Knives for cutting in place of wire. as “piano-wire,” which combines the greatest strength with durability, and is best adapted for the purpose because the thin¬ ner the wire the smoother will be the cut. For cutting - cakes from single bars the machine shown in Fig. 60 is a convenient arrangement. ***** In the case of toilet soap, before pressing the cakes, (if they are to have a smooth surface) the bars after cutting and slightly drying are sometimes planed by drawing them over a machine arranged like an ordinary carpenter’s plane turned upside down, Fi£. 60 . which takes off a thin shaving and leaves the surface of the bar very smooth, giving the cake after pressing an improved appear¬ ance and decreasing its tendency of sticking to the dyes in pressing. Instead of wire for cutting the slabs into bars, steel knives or springs placed similarly in the cutting machines having been recommended. It is difficult to keep them from bending under the strain of cutting, and they are not widely used; but those who have tried them claim that they make a smoother cut than does wire. The thinner the cutting wire, the smoother will it leave the surface of the soap. The Soap Factory. 141 DRYING APPARATUS. After being- cut into bars the soap requires to be dried some¬ what in order to be in a marketable condition and ready to be pressed. This drying process is in many factories still carried Natural drying, out by simply placing- the bars on racks and leaving- them there exposed to the atmosphere until in the proper condition. This, of course, is an unsatisfactory method, as the changes of the weather render it very uncertain and tedious, besides being- slow at best and requiring considerable room. A somewhat improved result is secured from drying rooms in which steam coils are placed to . raise the temperature; here also, however, the air in the room becomes laden with moisture, and unless removed promptly, the drying- still proceeds in an unsatisfactory manner. The best results are derived, undoubtedly, by combined heating and ven¬ tilation. Currents of dry, warm air, directly acting- on the soap, hasten the process and dry the soap in a most satisfactory way, causing- the formation of a firm, glossy skin over the surface which greatly aids in pressing- the cakes and enhances their fine appearance. For this purpose a “blower” or “pressure fan” is placed before a steam coil (which may be heated with exhaust steam of the engine) and connected air tight with a casing sur¬ rounding- the coil. On admitting- air into the inlet of the fan it is forced throug-h the bends of the coil and its temperature there¬ by raised. As is well known hot air can absorb more moisture than cold air, and therefore whatever the weather may be, the soap is sure to be dried by directing the warm current upon the racks. From 6 to 12 hours' drying is ordinarily sufficient to put the soap in condition for pressing, whereas in the old way the time required is very indefinite. A convenient method of connecting the operations of ventil¬ ation and heating, for drying soap, is shown in the accompanying drawing. The latter represents a coil of 1 inch steam pipe (not shown) in a casing of sheet steel to which is attached a disk fan. The temperature of the air forced through the casing can be reg¬ ulated, and is generally kept at about 100° F. for soap. The soap in the drying room into which the hot air is forced may be placed on drying racks or on cars which may be gradually moved forward to the hottest part of the room as the drying proceeds. (See Fig. 61.) A similar apparatus, made by the Buffalo (N. Y.) Forge Co., is illustrated in Fig. 62, and requires no further explanation. 142 The Soap Factory. Inlet It is suggested that iti warm weather the coils of pipe may be filled with brine, which has the effect of condensing the moist- Fig. 61. ure in the air, thereby rendering its drying capacity, in passing over the soap greater. When the air is naturally in good con- Fig. <>*2. dition for drying, the coil may also be left out of use altogether, the fan only being used for ventilating the drying room. THE PRESS. For forming the bars of soap into cakes, presses of great variety have been constructed, ranging from the small hand- press which stamps a few hundred cakes per hour, to steam presses having a capacity of several thousand cakes in the same time. The machines used in most cases are operated by foot power, The Soap Factory 143 the steam presses being- mostly reserved for the larger factories which turn out large quantities of a few special brands of soap. The Soap Factory 145 146 The Soap Factory Hand-presses are used but little in this country, where labor is generally too expensive for their slow work. In selecting a press, regard is had not only to the require¬ ments of the factory as to capacity, but also to the special kind of soap for which it is to be used, for while most kinds are best pressed by a machine giving a sudden blow, others, it is claimed, form Fig. 69.—Horsey Mfg. Co.’s Steam Press, a better cake when compressed by a more continuous pressure, such as is given by the downward turn of a screw. If, as is gen¬ erally the case, the press is to be used for various sizes of bars, H. Win. Dopp & Son’s Steam Press. & T! cri’ Iv 0 148 The Soap Factory. The Soap Factory. 149 the ready adjustment for different dies, and also for the force of the blow is to be considered. Ease of working, noiselessness, and stability are essential features, and it is also absolutely necessary that the guide for the dies be perfect, to insure the latter against undue wear. Lastly the arrangement for lifting the cake from the lower die must be so as to insure against defacing the impression by forcibly ejecting the cake against the top die. Herewith are illustrated a number of different soap presses, for foot and for steam power; it would lead too far to go into detailed descriptions of the same and their respective claims for superiority; we therefore contend ourselves with their illustration. Fig. 70, on page 147, represents a press which requires a few words of explanation. In this press the soap is handled auto¬ matically, that is, it is fed into the press and delivered there¬ from by belts, dispensing with the labor of putting the soap into the press a cake at a time by hand. The cakes from the cutting machine, after having been suitably dried on the racks, are placed on the upper belt shown in the cut and are delivered on to the lower belt after being pressed; from the lower belt the soap may pass to a table, or the belt may be continued in a horizontal di¬ rection, from which belt the soap is taken, or switched by foot to the wrapping table where it is wrapped and put in boxes immediately, the boys engaged in wrapping standing on either side of the belt and taking the soap as it comes along. The press is entirely automatic, feeding and delivering the soap by the mechanism perfectly, and it also thoroughly lubricates and cleans the dies between the pressing of each cake. It has a capacity of 360 boxes of soap of 100 cakes each per day of ten hours. The sdving of labor in the use of an automatic press will no doubt prove a very considerable item. The press is adapted to the pressing of all kinds and shapes of laundry soaps; the dies can be readily changed from one style or shape to another, and the pressure can be regulated at will. THE DIES. The dies in which the cake of soap is formed in the press require careful consideration, for on their construction depends, in a great measure, the appearance of the finished article, a mat¬ ter which has come to be of considerable consequence. We do not wish to say much about the material used in their 150 The Soap Factory. construction, as any manufacturer can buy good material. As long as a metal is used that will resist the corroding effect of the acids contained in soap, is tough and close-grained and the pro¬ per judgment and skill is exercised, a good die can be produced that will press any soap and in such a manner, as to produce a large-appearing bar with the least possible quantity of soap. Generally the entire set of dies is cast of the same material but sometimes there is substituted an iron box, lined with brass. This can be made a little cheaper, but when the die becomes worn there is no chance of refitting it, which easily can be done when the solid brass box is used. The design, lettering, ornaments, trade-marks etc., whether cut, raised or sunk on the die, should be made so, that it will readily shed the soap. At this point skill and experience on the part of the diemaker is required, as almost every grade of soap requires a different construction of the letter. A highly polished surface has no further advantage than to dazzle the eye and to conceal defects of the soap. An absolutely smooth surface, free from ridges, lumps and other irregularities should be looked for, as these will show the imperfections on the soap. Nickel and silver-plating has been resorted to to prevent corrosion, but when a good material is used and the dies are kept * The Soap Factory. 151 clean, there is rarely any necessity for this additional expense. The dies may be divided into two principal classes, namely: Ordinary or box dies and pin or shoulder dies, of which illustra¬ tions are given herewith. The ordinary or box die, Fig. 74, consists of three parts, box, upper and lower dies. For laundry dies the box is gen¬ erally made four inches high and of sufficient thickness to prevent spreading. The upper die is about one and one-fourth inches thick and the lower die of such a height, that the upper die will not enter the box more than one-fourth of an inch. For toilet dies, the lower die is made from two and a half to three inches and the box of a corresponding height to accommodate the thickness of the soap. This die is suitable for all grades of soap. Fig. 75. A—Box. B—Upper Die. C—Lower Die. D—Shank. E—Fixed Panel. F—Changeable Panel. G—Flanges. Fig. 75, gives a sectional view of the ordinary or box die, 152 The Soap Factory. which we here illustrate for the purpose of g-eneral terms when ordering- either dies or panels, which will be found of mutual benefit for both the manufacturer of soap as well as the manu¬ facturer of dies, so as to avoid misunderstanding’s. The cut further illustrates the necessity of having- the inner sides of the box absolutely parallel. If, for instance, the inner sides were tapered and the die fitted so as to press a one-pound bar, the latter would fit the box snugdy. Should one desire to press a 12-oz. bar in the same die, it would be necessary to raise the lower die about one-fourth of an inch and there would be sufficient space to let the soap escape, thus forming a feather- edg-e. Though the illustration shows a fixed or solid panel in the upper die, laundry dies are now larg-ely made with loose or chang-eable pannels and thus an endless number of brands can be pressed in the same die. Fig. 715. The Soap Factory. 153 This cut represents Christy’s Self Adjusting Dies which are similar in construction to the ordinary dies and are suitable for all grades of soap. They have in addition two steel guide-pins attached to the back of the upper die which enter into corres¬ ponding steel-lined holes in the box, thus accurately guiding the upper die to its place without the least danger of damaging the delicate edges. Hg. 7 7. Fig. 78, of another style die the box consists of two or more parts, grooved, tongued and securely bolted together, thus form¬ ing a box as strong as if cast in one piece. When the dies, after long use, become too loose, causing a feather-edge to appear, it is necessary only to separate the box, file off a trifle of the grooved surface and rejoin them and the die will be found in as perfect condition as when it was first received from the factory. This repair can be executed in the factory, can be performed by any employe and the die is always on hand when wanted and is easily kept in a perfect condition. 154 The Soap Factory Fig. 78. This die can be made with or without the patent guide-pin attachment and is suitable for all grades of soap but especially for soaps of a gritty nature, for which it was originally intended. The pin or shoulder die of which we give illustrations of The Soap Factory 155 different makers, Fig-. 79, consists of two parts, upper and lower Fig. no. Fig. 81. 156 The Soap Factory. dies. These dies are not practicable for the lower grades of soap and do not work well except in milled soap. The upper die has four lug's or shoulders, each supplied with a guide-pin, which enters into corresponding holes in simi¬ lar shoulders on the lower die, thus bringing the two halves together accurately. When pressing, these shoulders meet, pre¬ venting damage to the edges of the die proper. These dies are almost indestructible and have this additional advantage, that no matter how much soap is put into the die it will retain only the amount calculated upon, which in an expensive soap is quite an item. Fi£. 82. Christy’s Patent Combination Die, (Fig. 83), also made by several manufacturers, consists of three parts, box, upper and lower dies. The box receives the lower die, as in the ordinary The Soap Factory 157 or box die, but has in addition four lugs or shoulders, similar to those of the shoulder die, into which the guide-pins of the upper die enter, thus leading the latter into place. The upper die is similar to that of the shoulder die and if the lower die is fastened so that the top of same is flush with the top edge of the box, it will be a complete shoulder die. By a simple adjustment it will press a cake of any thickness as is done with the ordinary or patent dies and still has the advantage, that no matter how much Fig. 88. soap is put into the die, the intended amount only is retained, which, for the higher grades of soap, is worth considering. 158 The Soap Factory. Fig - . 85 represents an ordinary toilet set of dies showing- how interchangeable panels are set in dies. In this connection we illustrate herewith (Fig. 86) a very simple device for protecting- the workman ag-ainsta common form of accident while pressing- soap, in which operation a great many people have been more or less seriously injured. To prevent the workman from cutting off his fingers in the press, a block of wood is fastened to the right of the die box, conforming in size to that of the latter. Guides are provided in the form of two The Soap Factory. 159 Fig. 85. strips, curved at the end to permit the bar of soap to enter read¬ ily. A bar is placed on the block and then pushed on the die box by another cake to be pressed next. When the first cake has been pressed the workmen can safely remove it while the top die is up; then the second bar is in turn moved forward by a third one being* placed on the block, and so on. After the workmen are once used to this arrang*ement there is no trouble whatever arising* from the use of this safeg-uard. An improvement in this direction has been suggested which consists in depressing* the wooden block about a quarter of an inch below the surface of the die box, and cutting* away the adjoining* 160 The Soap Factory side of the die box to the level of the block. In this case the cake of soap may be fed forcibly to the opposite side of the die box and held there momentarily by a light pressure on the extra cake; it will then fairly drop in on withdrawing the extra cake. Still greater safety is obtained by attaching to the face of the block an upright piece which will prevent the operator’s hand from passing over the die box when feeding the press. The work Fig-. 87. of the operator may be facilitated by having the block at least twice as long as the cake to be fed. This would enable him to place a cake upon the block with his right hand while the left hand is feeding the preceding cake in the manner described. The operation of pressing soap and the proper care oTthe The Soap Factory. 161 dies will be described in a succeeding- chapter, but while on the subject of safety it should here be mentioned that in feeding- the ordinary press, without the safety devices described, the work¬ man should invariably handle the soap with the thumb and index finger of the hands, grasping- the bars midway between the upper and the lower surface. Nearly all accidents that occur are the result of handling- the soap by grasping- the bars with thethumb and middle finger, letting- the index fing-er project across the cake, and thus exposing- it to the dang-er of being- cut off. Fig. 88, shows an ordinary set of laundry dies with improved hand slide. These slides are made for feeding- with either rig-ht Fig. 88. or left hand. Some operators place a bar on the side and instead of following- it with a second bar, they push it into the die box, the bridg-e preventing- the fing-ers from being- crushed under the upper die, the top level of box being- hig-her than the surface of slide, it prevents the bar of soap from g-oing- over it, the bar being swiftly pushed, it is prevented from dropping into the box at an angle but will fall into proper place, flat on the top of lower die. 162 The Soap Factory. HAND STAMPS. In place of pressing- the soap by means of press and dies, some soaps are merely stamped; this may be done on the cutting- table as stated already in the description of the soap cutter, or box metal or electrotype hand stamps may be used. These elect¬ rotypes should have clear, sharp letters and be heavily faced to withstand the wear. Fig. 80. Fig. 00. Fig. 01. 163 The Soap Factory. Fig:. 92.—(See page 164.) Fig. 93.—(See page 164). 164 The Soap Factory. JAM E S ATI<1 S S.MA 2 TOMPKINS AYE BROOK.LYN.N.'r. ^ PAT -applied vn I ; lllialfflfl i i \i'a 1 I |n iii i\i | THE SOAP CHIPPER. Instead of forming' the soap into stamped bars, it is often chipped up, especially for use in laundries, or when it is to be “milled.” Fig'. 92 and 93, show machines used for this pur¬ pose; the former is made by Brown & Patterson of Brooklyn, N. Y., and the latter by Rutschman Bros, of Philadelphia. The soap placed in the hopper is fed automatically to the knives. The latter are adjustable to cut different thicknesses. ******* It only remains now to merely mention the simple tanks used for special purposes, as for bleaching - , for measuring' and storing - oils, for making- sal soda solutions, etc., and the ordinary machin- Fig. 94. ery used in all kinds of factories, as elevators, boiler, engine, shafting-, etc., and we may close this chapter, so far as a laundry and ordinary toilet soap factory is concerned. The Soap Factory. 165 There are, however, the following- special machines still to be considered for factories making- “milled” toilet soaps. THE SOAP MILL* For making- the finest quality of toilet soap the process known as “milling-” is employed. The advantag-es of the same are obvious when it is considered that thereby perfume may be added to the soap when cold, that the soap is dried thoroug-hly before milling and therefore does not warp or shrink in the least, nor lose weig-ht, and that soap in general is improved by repeatedly working it over. The bars are chipped up, thoroughly dried and then fed into the mill where the soap is ground together with the perfume and Fig. 95. color desired. The mixture is passed several times through the machine until perfectly homogeneous. From the last roller the soap comes in a thin film that is cut automatically into narrow ribbons, which fall into a box placed under the machine. 166 The Soap Factory The mills are made in various sizes and styles closely re¬ sembling* each other, so that the illustrations presented on pag*e 164-165 will answer for all. Fig*. 94, represents a mill made by Brown & Patterson of Brooklyn, N. Y. Fig*. 95 is a mill made Fig. 90. by Rutschman Bros, of Philadelphia, Pa. Fig*. 96 is made by Houchin & Huber of Brooklyn, N. Y. THE PLODDER. This is a machine into which the soap is fed as it comes in ribbons from the mill, in order to form it, by an enormous pres¬ sure, into compact bars. Formerly machines were used which had to be refilled after compressing* a small quantity of soap with which they were charg*ed. At present, however, continuous plodders are in g*eneral use, from which the soap issues in one The Soap Factory 167 Fig. 98 168 The Soap Factory continuous solid bar, so long- as more soap is fed into them. The soap, compressed by means of a screw which works the contents towards the outlet, issues from the nozzle seen at the left of the illustrations herewith, (Fig-. 97-98) and may at once be cut up into bars and pressed into cakes, without requiring- drying-. The opening- in the nozzle may be g-iven any desired shape by means of different dies, so as to approximate the shape of the cakes to be formed, and is kept warm by means of a g-as flame, so that the soap will come out smooth and gloss} 7 . These plodders are made with a jacket throug-h which cold Fig. \Hh water may be circulated to prevent the machine and the soap from becoming- hot throug-h continually working-the latter under so hig-h a pressure. It is found, however, that when heating actually does occur, the beet results are obtained b} T simply allow¬ ing the machine to rest until it cools off by itself. The bar of soap coming from the plodder is cut into short pieces, corres¬ ponding to the size of the cake, by means of the cutter illustrated on page 140. The Soap Factory 169 Fig-. 98 represents the Atkiss plodder, made by Brown & Patterson of Brooklyn, N. Y. This machine, at each stroke, forces out a bar of soap from 3 to 5 feet in length. Its motion is continuous and the feed automatic. Fig - . 99 represents one of several styles of plodders made by Houchin & Huber of Brooklyn, N. Y. * ****** A new system of making- milled soap has been patented by a firm of soap manufacturersin Belgium, consisting of machinery in which by means of a system of hollow cylinders revolving at increasing rates of speed, and through which the air circulates, Fig. 100. hot soap directly from the kettle may be cooled down to the “sett¬ ing” temperature in a very few minutes; it is then carried on endless belts into a drying chamber into which hot air currents are introduced and from which it emerges sufficiently and evenly dried ready for the plodder. The perfume and color are added in a special mixing vessel just before the soap is brought upon the cooling cylinders. This system has not as yet been largely 170 The Soap Factory. introduced into the United States, but is reported to give fair results, as it saves the time, k.bor and space now required for framing and cooling the soap in large blocks, only to heat it again for drying purposes after chipping it up. See illustration of this system opposite page 103. The smaller utensils, such as hand crutches, buckets, etc., have been so frequently described and are so fast disappearing in their use that a description is hardly necessary here. We represent herewith (Fig. 100) also one form of the many grinding mills used for making soap powder. This particular form, made by the Foos Mfg. Co., Springfield, Ohio, has been specially designed for this particular purpose. Finally, in addition to the pipes, valves, shafting, belting, &c., required in a factory of an} r kind, the soap factory requires such special apparatus for the economical use of steam in manu¬ facturing processes as reducing valves, steam separators, &c., one of which we illustrate herewith as representative of its kind i. e. the Eclipse Separator for live and exhaust steam, as devised by the John Davis Co. of Chicago. PART II. ■ CHAPTER VI. The Manufacture of Soaps. SELECTION OF MATERIALS AND ITETHODS. On commencing- the actual manufacture of a soap, a number of questions present themselves for the consideration of the man- facturer, which he must determine beforehand in order to obtain the desired results. Soaps for different purposes require different raw materials; the different treatment of the various materials requires different manufacturing- facilities. Ag-ainsoapsof certain characteristics are made by special selection of materials and methods, and according- to the equipment of a factory different means must be adopted at times for reaching the same or similar results. Closely interwoven with all these and other questions is always the matter of cost. We will here make a systematical survey of the preliminary questions to be answered. FOR WHAT USE IS THE SOAP INTENDED? This is undoubtedly the first question to be decided, as the adaptability of the soap to the purpose for which it is to be applied is important above all other considerations. It is obvious that a laundry soap must possess different qualities from a shaving soap, and that a tooth soap will not be popular if made on the lines which are applicable to a first-class scouring soap. Laundry Soap, as most popular in this country, is generally Stock for launch made of tallow and a moderate proportion of rosin. The tallow soa P s - may be partly or wholly substituted by grease, cotton seed oil or foots, palm oil, red oil, cocoanut oil, etc. The basis of this soap are the fats named, while rosin is used partly because it is cheaper 174 The Manufacture of Soaps. \ Effect of rosin. Hardening by sal soda. Unfilled laundry soap. Neutrality of toil- «t soap. than fats, and partly because on account of the easy solubility of rosined soaps they wash more rapidly than soaps made wholly of fat. The better grades of this kind of soap contain about 35 lbs. of rosin to hundred pounds of fat, too large amounts of rosin being* undesirable in a soap as making* it too soluble and sticky, and leaving* it with too little of the fat soap in which, after all, lies the principal value of a g*ood article, so far as washing* power is concerned. An addition of rosin just larg*e enough to effect its purpose is perfectly legitimate, and the evident preference of most consumers for such soaps refutes the argument sometimes made that rosin, even in small proportions, should be considered an adulteration. As by the addition of rosin the soap is softened somewhat, it is generally hardened by adding (in the crutcher) a strong solution of sal soda which, by crystallizing in the soap and by a peculiar effect on its structure renders it harder. In wash¬ ing this soda also aids in the cleansing effect of the soap, partly by promoting its solubility and partly by its own detergent properties. Some soaps are also made of fat and rosin, without filling; where their slightly slower work is not objected to, they may be consi¬ dered as ideal laundry soap(provided soft water is used with them), particularly in this country where the climate is such that a pure tallow soda soap would soon dry out to a point where it would become practically insoluble. Laundry soaps differ from toilet soaps in many particulars ; for instance, they are not generally required to be entirely neutral, a somewhat alkaline soap being more effective, especially in localities having very hard water ; they are less elegantly perfumed, are sold at considerably lower prices, and less predominance is given to their fine appearance. Nor are laundry soaps generally required to produce so rich a lather, and so rapidly, as is demanded of toilet soaps. Besides personal preferences are divided between rapidly washing or mild, very soluble or economical, cheap or good soaps ; in these respects the demand of the customers-must be the guide of the manufacturer. Toilet Soaps are, or rather should be made, entirely neutral, as anv excess of alkali present that is not combined with fat into soap attacks the skin while washing and renders it rough. Great care is therefore required in making a good grade of toilet soap, that the fats employed shall be thoroughly saturated with lye without any free alkali being left in the soap when it is finished. Similarly the addition of filling, particularly such as carbonate of soda, pear The Manufacture of Soaps. 175 ash, etc., is much more appropriate for laundry soaps than for toilet soaps. The fats employed for making 1 toilet soap must be selected with regard to the properties of the soap which they form with lye. Thus tallow-soda soap lathers too slowly to be used alone; pure cocoanut oil soap lathers very freely, but its continued use is not borne by every skin without having a bad effect, and its smell is peculiarly unpleasant; grease is too impure, generally, to be made into a soap that will preserve its fine perfume and not turn rancid in course of time. It will be seen from this that for making good toilet soaps special consideration must be given from the start to the selections of the fats, to their proper treatment, to a process of making them into soap actually free from uncombined fat and lye, and to their appearance, color, texture, and perfume which are of far greater importance, commercially, in this kind of soap than in the grades for ordinal household use. The use of some potash in place of some of the soda is of quite noticeable advantage in toilet soaps, as it improves the tex¬ ture, and also its lathering properties, on account of the greater solubility of potash soap. For trade in many country places a soap is required which, while cheap enough for household purposes, shall also be fairly good for personal ablution. This demand is frequently filled by soaps which are neither one nor the other, combining the proper¬ ties of a somewhat mild laundry soap with those of a rather poor toilet soap. It will be seen that toilet soaps vary from the soaps for ordi¬ nary uses only in the selection of the best materials and more care¬ ful manipulation ; but people having a healthy, tough skin, frequently can use even a somewhat alkaline soap with immunity, and many cheap soaps are sold for toilet purposes which in point of purity and mildness are even behind some of the laundry soaps in the market. Few people with sensitive skins, and especially ladies and children, the use of such articles is often attended with irritating effects. Shaving Soaps are a class distinct from either of the foregoing. They are required not only to furnish a rich lather, but also that the latter shall remain on the face for some time without drying ; they shall soften the beard without attacking the skin ; they must have no unpleasant smell, and yet but little perfume must be used in them. These soaps will be specially described in succeeding pages. Stock for toilet soap. Potash in toilet soap. Shaving soap. 176 The Manufacture of Soaps. Use of textile soaps. Requirements of textile soaps. Textile Soaps. Woolen manufacturers, wool washers, worsted spinners, silk dyers, calico printers, etc., use considerable quanti¬ ties of soap, especially for scouring- and fulling- purposes. Raw wool is cleansed of grease and dirt by washing-, potash soap being almost universally conceded to answer best for this purpose ; it is then treated with oil in order to bring- itintocondition forspinning into yarn which is then woven into cloth. The cloth is then ag-ain washed or “scoured” in order to remove the oil used in spinning-; for this soda or potash soap is used. The fulling process consists in spreading soap over the cloth and subjecting the latter to fric¬ tion, thereby entwining the fibres of the wool in a manner which thickens the cloth ; at the same time the cloth is cleaned by this operation. The soap in this case acts as a lubricant. The calico printer uses soap to remove certain gums, dextrin, starch, etc., applied for printing purposes. In the manufacture of silks soap is needed to free the fibre from extraneous matters, and also in the process of dyeing. Considering the various uses for which soap is employed in woolen mills and other textile manufactories, and the various degrees of care bestowed on the work by the men entrusted with the same, together with prejudice and ignorance, it is not sur¬ prising to find that it is by no means agreed what constitutes good soaps for the textile industries. What the soapmaker must do therefore, is to fqrnish the kind of soap which is demanded, and leave it to his customers to decide what they want. Yet it is well for the manufacturer to be familiar with the action of different soaps in the treatment of cloth, so that he may know where the blame belongs when his product should meet with complaint from the consumer. At the outset it must be understood that really every good soap, thoroughly saponified , may be used in textile manufacture, and even cold made soaps, filled with silicate, starch, etc., find cus¬ tomers, although actually hardly fit for such uses. Some manu¬ facturers require a perfectly neutral soap ; but more frequently one that is strongly alkaline is preferred. For ordinary woolen goods that have not been dyed a somewhat alkaline soap is quite suitable, but most colors are readily dimmed by free alkali. The natural color of wool is bleached slightly by potash soaps, while soda soap—unless very carefully used—is apt'to turn it yellowish. A too strong soap, whether made of soda, or potash The Manufacture of Soaps. 179 cocoanut oil soaps, salt and water allow of an enormous increase, beside that by the before-mentioned fillers, so that the manufac¬ turer can sell at a very low price, provided he has carte blanche as to quality. (The effect of these various editions is further ex¬ plained on other pages of this book.) SPECIAL PROPERTIES OF THE SOAP. Floating Soap. This conists of a hard soap into which air bubbles have been incorporated while the soap is still hot. These air bubbles are so small as to be almost invisible, and so numerous that they largely increase the surface of soap exposed to the water when the same is in use. Naturally such soap is more quickly sol¬ uble than the same article would be if it were not made to float, and regard to this fact should be had in determining on the mate¬ rials and process for making this variety. Transparent Soap. Transparency is a property which conve} r s to the average buyer the impression of purity, although as a fact a perfectly pure soap is, under ordinary circumstances, no more transparent than is pure tallow or pure butter. By dissolving it in alcohol and subsequent evaporating the latter, soap may be made transparent. The same result may be, and generally is, brought about by the addition of glycerin and sugar dissolved in water, with or without the further addition of alcohol. Alcohol and the process of recovering it being expensive and troublesome, trans¬ parent soaps are mostly made by the addition of much syrup, less glycerin, and as little alcohol, if any, as possible under the cir¬ cumstances. The glycerin in such soaps is, perhaps, a desirable feature, although it causes the soap to attract moisture and become wet on the surface in certain weather. The use of some castor oil with the other fats tends to cause transparency and to improve the texture of the soap, but it slightly reduces its lathering qualities. Hard Water Soap. Water containing in solution such com¬ pounds as carbonate of lime and magnesia, sulphates of the same, or ordinary salt (sea water), is not well adapted for washing, as salt water is incapable of dissolving ordinary soap, while the lime and magnesia compounds present in most hard waters decompose the soap with the formation of insoluble lime and magnesia soaps. With such water cocoanut oil soap is the only one capable of doing effective work. (Palmnut oil soap is similar to the latter, but not made to any extent in this country.) For slightly hard water 180 The Manufacture of Soaps. rosin soap, or soap containing- a small excess of alkali, are some¬ what better adapted than that containing- no rosin. “Boiled Down” Soap. Soaps that ha.ve been boiled and “set¬ tled,” as will be described hereafter, contain a proportion of water more or less great, according to circumstances. The more water a soap contains, other things beingequal, the more readily it is solu¬ ble, the faster will it wash, and the more of it is wasted in use. Where an economical soap is preferred to one that washes rapidly, or where the raw material used naturally furnishes a soft product, the soap is boiled down so as to reduce the proportion of water. Such soap, during the process of boiling down, and through the consequent loss of water, becomes of a peculiar consistency which does not permit the coloring matter and other impurities present to settle to the bottom; these, therefore, remain in the body of the mass, and, by a process of crystallization in the hot soap, become distributed throughout the mass in vein-like formations, producing the “mottle” or “marble” peculiar to boiled down soaps. (If Artificial mottle, boiled down too far the mottle will not form, however.) This marbled appearance was formerly taken as a guarantee that the soap contained but little water, and has therefore come to be more or less successfully imitated artifically in soaps containing much water. By the loss of water during the boiling down the soap is also hardened, and where oils are used which naturally form a rather soft and easily soluble soap, such as cotton seed oil and red oil, boiling down is often employed. In the case of cotton seed oil boiling down also has the additional advantage of preventing the yellow spots already referred to. Ordinarily the soaps made in this country are nearly all settled soap, so far as they are at all made by boiling. A peculiarity of boiled down soaps is that they “sweat,” i. o., attract moisture in damp weather, owing to the presence of foreign salts derived from the liquid on which they are boiled down. BY WHAT PROCESS SHALL THE SOAP BE MADE? The size and facilities of the factory, the prices of its pro¬ ducts, and the quality and appearance of the same, demand several methods to be employed in different cases. Advantages of the The “Cold Process .” The easiest manner of making soap consists in simply mixing the melted fat with strong caustic lye until a thick mass results which at first becomes heated spoil- The Manufacture of Soaps. 181 taneously by the chemical reaction taking* place ; upon cooling in the frame in the course of a few days the soap is ready. The advantages of this “cold process” consist in the first place in simplicity and a fine appearance of the finished article while the soap is fresh. The gdycerin formed in the process of saponifica¬ tion of course remains in the soap (as does in fact everything* that g*oes into the mixer). Very small quantities may be conveniently made by this process, and at a comparatively small expense in time and labor. The disadvantages of the process are, however, quite important. It is practically impossible to make the soap as perfectly that more or less free alkali and free fat do not remain uncombined and mixed in the soap, causing harshness by the free alkali, and rancidity after a time and other bad features, on account of the free fat; the quantity of lye re¬ quired to saponify a given amount of fat cannot even be calculated exactly in practice, as both fats and lye var} 7 in composition ; but even with an excess of lye used the presence of uncombined fat cannot be avoided. Moreover the fats require to be previously clarified carefully. Fats containing free fatty acids are entirely unsuitable for the cold process. (For further particulars see Chapter XIII.) The “Half Boiling ” Process. This is a method of making soap at a higher temperature than is employed for cold-made soap, but without actually boiling. It yields soaps similar to that made by the cold process, but permits of somewhat more thorough saponi¬ fication (and also, incidentally, of the addition of considerably more “filling” matter). The Boiling Process. Although this is the process by which soap was made in the olden times, it is still the best method at this day, notwithstanding the many attempts to improve upon it. Only the use of steam instead of an open fire, and the use of ready¬ made caustic alkali instead of leaching carbonates with lime in the soap factory are to be recorded as essential departures from the primitive methods of the ancients ; but open fire is still largely employed in other countries,, while the causticizing of carbonates by the soap maker is even now practiced in this country to some extent. For making soap, and especially when large quantities or the best qualities are to be made, nothing can be simpler than boiling the fats with caustic lye, for the following reasons: The object to be attained is to bring every particle of fat into intimate con- Disadvantages of the cold process. Advantages o f “half boiling.” Advantagesof the boiling process. 182 The Manufacture of Soaps. Boiling necessary for perfect sa¬ ponification. Uivision of boiled jfoapfi* tact with lye; it is therefore the first requisite that the fats should be melted, in order to acquire the necessary fluidity. Next, the fat and lye must be very thoroughly mixed with each other, which can in no way be done more effectively or more cheaply than by increasing the heat—required anyway—to the boiling point. The boiling can be continued as long as desired, so that the soap maker has perfect control over the operation ; this he cannot have in the cold process, and the result is that only by boiling every trace of fat can be saponified. Then, again, it is only by various operations made possible by boiling that the gly¬ cerin formed in the course of saponification, the excess of lye, and numerous impurities contained in the fats and in the lye can be removed ; the consequence of this is that well boiled soaps, made neutral and freed from foreign matter, wash away less rap¬ idly than cold made or half boiled soaps, and do not become rancid in time by the presence of free fat. The boiled soaps, as usually made in this country, may be divided into two classes: “Settled” and “Boiled Down” soaps, besides the “Run” soaps, which are hardly made any more, however, at the present time. The settled soaps, which are those produced in the greatest quantities, are made by allowing the hot soap, while rather thin, to settle in the kettle, so that the impurities, the foreign salts, and the excess of lye and water, to¬ gether with some of the soap, form a dark precipitate called “nigre,” from which the pure soap is drawn off. Such soaps contain a greater proportion of water than “boiled down” soaps, which have already been briefly described on page 180. “Run” soaps were made by simply saponifying the fat by boiling with lye, and framing the mass obtained with such liberal allowance of water and filling as was desired. [Since the first edition of this treatise the process of boiling soap under pressure—with the object of saving time and, as was claimed, increasing the yield—made its appearance once more, but found no favor. We mention it here only for the purpose of adding to it a few words on a rather interesting patent granted to C. Polony, of Vienna, who uses the boiling under pressure for a novel purpose: He slowly heats the fats in a closed vessel with ammonia (sp. gr. 0.96 to 0.875), gradually raising the pressure to 5 atmospheres ; ammonia soap is formed which is then grained with salt solution while again boiling in the closed vessel ; the salt (chloride of soda) changes the ammonia soap into a soda soap, The Manufacture of Soaps. 183 while in the waste lye are found chloride of ammonia and gly¬ cerin ; from the former the ammonia is regained by distillation with lime, to be used again in the next batch. The advantages as claimed by the inventor are the doing away with the necess¬ ity of using caustic, a better quality of glycerin, and a saving in time (?). The saponification with ammonia takes place under these circumstances owing to the fact that under pressure the vapor of ammonia separates the fatty acids from the glycerin and the former then combine with the ammonia]. Milled Soap. The mechanical process of milling has for its Advantageaof object the forming* of cakes of soap which will not shrink with age, retain a fine appearance, an even texture, and are finely per¬ fumed while the soap is cold, so that a minimum of perfume only is lost by evaporation. Milled soaps contain only a small percentage of water, as they must be thoroughly dried before being treated by the machinery described on the preceding pages, and they consequently preserve their original shape indefinitely. A well dried, neutral, boiled soap may be mixed with colors and perfumed and be worked into the finest and best articles for toilet purposes. By this process, however, cold Cold made soap made soaps are frequently milled also, in order to take advantage for milling, of the popular favor in which milled soaps are held, although in this case milling is of little practical benefit to the soap, except perhaps in so much as it becomes a little milder by being exposed to the air and by the repeated handling. An ordinary cold made soap is amorphous in structure, while milled soap shows a grainy or fibrous formation, in consequence of which the ends of the cakes, after pressing, have a different appearance than the cakes of either cold made or ordinary boiled soap. At present the mill¬ ing process is confined to the manufacture of toilet soap, but in view of the constantly improving character of laundry soaps, and the improved machinery likely to become popular some time in the future, it would not seem improbable that milled laundry soap is yet among the possibilities. REMELTED SOAP. For making toilet soap from stock soaps, but more often for working up scraps of soap without boiling them over, remelting may be resorted to. For the manufacture of toilet soap the process of remelting is mostly confined to England, where the soap manu¬ facturer furnishes a well boiled soap to the perfumer, who colors, 184 The Manufacture of Soaps. perfumes and works it over into cakes of toilet soap by remelting-. In this country toilet soap is g-enerally made by milling* or by the cold and half boiling* process. But for working- over the scraps of soap, remelting is the most convenient and economical way. The cold process permits of hardly any other convenient means of utilizing scraps, while the reboiling of scraps would cause the loss of the filling which would go into the waste lye, and of the perfume. CHAPTER VII. Settled Soaps. The settled soaps are those made, brie fly stated, by boiling' the fats, oils, and rosin with lye until thoroughly saponified, se¬ parating and drawing off the waste lye, “ strengthening ” and washing with a change of lye, and subsequently thinning the soap out with water, whereby the excess of alkali and other im¬ purities are settled to the bottom of the kettle, as more fully described hereafter. The last mentioned operation is technically termed “pitching” or “settling.” This is the most—not to say the only—practical process for making a thoroughly saponified and at the same time perfectly neutral piece of soap. Even a soap that has been boiled down without previously settling it (a process by which, for instance, the true Marbled Castile is made) always contains some free caustic alkali. The settled soap* may be conveniently divided into those containing rosin (yellow soaps), and those not containing it (mostly white soaps). We will first describe the former. ROSIN SOAP. The settled rosin soaps are made either of tallow and rosin, or grease, stearin, palm oil, cocoanut oil, cotton seed oil, etc., may be substituted in place of part or all of the tallow. For soaps containing a large proportion of rosin, fats rich in stearin are best suited, while the softer fats and oils are more suitable for soap in which little or no rosin is employed. This adaptability of the different fats rests on the solid consistency and comparatively small solubility of the soap formed by the combina¬ tion of stearin and soda. Rosin softens such soap and makes it Definition of set¬ tled soaps. Selection of stock. 186 Settled Soaps. Settling or clari¬ fying the stock. more soluble. On the other hand, the softer fats and oils, contain¬ ing- less stearin, form soaps, which are naturally soft and easily soluble ; they are consequently adapted for use in connection with much rosin only when a “boiled down” soap is to be made, in w T hich case the decrease in the quantity of water present counter¬ acts the softening- effect of the rosin. Cocoanut oil, used tog-ether with other fats in a rosin soap, increases the solubility still further, but the soap will be harder than a tallow-rosin soap that had been made equally soluble by the use of a larg-e proportion of rosin. It will also lather more freely. The better grades of settled rosin soap are made of fats and rosin in the proportion of about 35 lbs. of the latter to 100 lbs. of fat, and mostly with the addition (in the crutcher) of about 6 to 8 per cent of a strong- solution of carbonate of soda to the finished soap, for the purpose of hardening it and increasing its detergent properties. Cheaper varieties are made by using ordinary grease in place of the tallow or the other fats and oils used; also by in¬ creasing the proportion of rosin (up to 100 per cent and more of the fat used), and by “filling” with silicate of soda, talc, silex, mineral soap stock, etc. Taking a soap of tallow and 35 per cent rosin as the basis for a description, the process of manufacture is conducted as follows: Saponification of the Fat. The clear fat is drawn from the settling tank into the clean kettle; or, in the absence of a settling tank, and if there is no “nigre” in the kettle, the tallow is run into the latter as it is melted out of the barrels, and clarified by boiling it on water to which some salt and some alum have been added. The dirty water is then run away after a short rest. The use of a settling tank is always to be recommended, as it will permit of examin¬ ing the fat for adulterations, many of which settle out while at rest; and also because the clarification by boiling on salt water can be conducted in it, while the kettle is otherwise occupied. It will also be well to take notice of the amount of lye absorbed by the fat, and should a certain lot of fat use noticeably less lye than usual it will be advisable to examine it for unsaponifiable admixtures. Settled Soaps. 187 The salt has no other effect in this operation of clarifying’ than to cause the dirty water to settle rapidly after boiling - , in consequence of the increased gravity communicated to it by the dissolved salt. When the water has been drawn off, the clear fat is ready for saponification in the same manner as if it had been drawn from the settling - tank. Alum may be used, tog-ether with the salt, to remove gluey impurities contained in much of the greases and tallow found in the market. The same preliminary treatment of the fats is indicated when lard, stearin, grease, cocoanut oil, &c., are to be clarified; many impurities are thereby removed which it is difficult, or even quite impossible, to eliminate from the mass after saponification. A different method of clarification consists in using strong lye instead of salt water, and only working the contents well through with steam, without heating more than necessary to accomplish this; then applying just enough steam to separate the dirty lye well from the fats, and drawing it off. The clear fat is next saponified, or “killed,” as it is termed, by running lye into the kettle and turning on open steam, or both the open and closed steam. “Tallow,” it ufeed to be said when our commercial caustic was not of as high grade as it may now be had, “requires weak lye at first, as it combines with strong lye only after it has been already partly saponified.’ 1 The lye was, therefore, run in at a strength of 8 to 10 B. at first. But this behavior was due to the foreign salts in the caus¬ tic, and if the lye is made by dissolving caustic soda of high grade in water, it might be used much stronger from the start, and would still combine with the tallow; only the resulting mass would be too thick to boil freely; so weaker lye is either used, or stronger lye and water are run into the kettle together. Cocoanut oil combines readily with strong lye, and in doing so draws the tallow into the combination if both are saponified together. If, therefore, the fat consists of both, tallow and cocoanut oil mixed, instead of tallow alone, the lye—even if made from the lower grades of caustic—may be used stronger from the beginning in the ratio as the proportion of cocoanut oil to tallow 7 is larger. Palm oil, stearin, and grease are similar to tallow in this respect; cocoanut oil only finds a counterpart in palmnut oil and in free fatty acids. Another method of clarifying. Strength of lye to begin saponifi¬ cation. I 188 Settled Soaps. Too weak lye only adds unnecessary water to the boil and retards the chemical combination. When, on the other hand, * the lye used is made of low grade (say 60%) caustic and applied too strong at any stage of the saponification, the partly formed soap is unable to remain dissolved in it; it then coagulates or “opens” (so that the lye can be observed to separate from a sam¬ ple taken on the paddle or trowel) thereby preventing the proper action of the lye on all the particles of fat. If this condition should set in at any time during this operation, weaker lye must be added until the mass “closes” again. But if the lye was made of high grade (say 70%) caustic, then the soap will either not open at all, or close by itself after a few minutes’ boiling, should the lye be too strong at any time. The lye used in this operation may be made by dissolving in water caustic of 60% or of 70%, or of any other grade desired, according as convenience of working and cost of the caustic may dictate. The action of lye of different grades in this respect has been explained above, and also on pages 73-76, and we need 1 / the e:ir " therefore merely repeat more especially that the carbonate of soda in all lower grades of caustic does not combine with neutral fats, and will'therefore be lost by running away the waste lye afterwards, unless precautions are taken to absorb it previously to running away the waste lye, by the addition of some free fatty acid, or rosin. This utilization of the carbonate can only be effected, however, when there is no more caustic alkali present in the kettle, as otherwise the rosin or free fatty acids would combine with the latter in preference to the carbonate. The lye is run into the kettle in a steady stream, and under constant boiling. The presence at any time of a large surplus of lye in the kettle only retards the process of saponification, but a lack of lye at any time must also be guarded against, as it would cause “bunching” (a thickening up of the partly formed soap). The \ye is therefore added only about as fast as the fat is able to absorb it, and not fast enough to disturb the even ebullition of the mass. “Bunching.” When working with a large kettle, in which “bunching” would be especially troublesome, requiring hours of work and boiling to overcome, it is advisable to run in lye and fat together from the start, thereby saving time and reducing the risk of bunching at the same time. This is especially necessary if the fats contain free fatty acids in large proportion, which combine Settled Soaps. 189 very quickly with lye, and are thus particularly liable to cause the trouble mentioned. Should bunching of the soap take place, very strong lye or salt water must be run in, the steam turned on full, and the con¬ tents well worked through until they are brought back to the normal state. In the case of a small kettle this process may be assisted by vigorous crutching. To regulate the strength of lye, strong lye and water may be run in together, gradually decreasing the proportion of water. (A convenient arrangement for this purpose may be found under the description of the lye tank, on page 94.) The saponification or “killing” of the grease is most ad¬ vantageously performed by boiling slowly with open steam, which, by the pressure with which it issues from the perforated pipe, causes a brisk movement in the contents of the kettle. When the kettle has both open and closed steam, satisfactory results may be obtiined by using both; when boiling with closed steam great care is necessary, however, as the steam pipe remains hot for some time after shutting off the steam, and a boiling over might be impossible to prevent if once started with a hot closed coil. The heat developed spontaneously by the combination of the materials taking place is often sufficient to cause boiling over even when all steam has been shut off; it is therefore often ad¬ visable to have water or salt water handy to sprinkle over the soap in case of necessity. In all operations of boiling it must be remembered that the open steam adds its condensing water to the mass and causes a strong agitation in the contents of the kettle; the closed steam, on the other hand, causes a slower, even ebullition, and removes water from the kettle by eva¬ poration. This operation of saponifying the fat (also called “First Change”) is considered complete when the soap formed will not absorb any more lye, and, after boiling for a reasonable time without the addition of more lye, indicates by the peculiar “sharp” alkaline taste that the last lye added remains uncom¬ bined in the kettle (the soap has surplus strength). At this stage the mass begins to be clear; a small sample taken on a piece of glass is transparent and remains so until it cools off. Pressed between the fingers it should have a good body and not be smeary; a sample taken on the thumb and pressed in the palm Use of open and closed steam.' End o f first change. 190 Settled Soaps. of the hand by sliding- the thumb over it, must curl into a rather dry shaving. When the proper signs mentioned are absent, although the soap has a sharp taste, it indicates the presence of unsaponified fat, owing to the lye used having been too strong, so that it could not act properly on the fat. The addition of weak lye, or even water, or boiling a little longer, will then be required to cause the soap to absorb more lye. The total quantity of lye required for the saponification is roughly estimated at 100 lbs. lye of 20° B. to every ICO lbs. of stock. Cocoanut oil requires a little more lye than ordinary fats. The exact quantity of lye necessary for saponifying a fat is not required to be calculated in making soap by boiling, and is there¬ fore made the subject of some special remarks in another chapter of this treatise. It is a not uncommon error to believe that when the soap shows some sharpness after the boiling has continued for a few minutes without the addition of more lye, the fat must be per¬ fectly saponified. This assumption, however, is often far from the truth, for even after the soap has been again boiled on fresh lye, it very frequently still contains unsaponified fat. Indeed, many—not to say most—ordinary soaps on the market contain free fat from this cause. A thorough saponification is only effected by prolonged boiling with sufficient l} T e of proper strength to permit combination. Graining. When the saponification has proceeded until the before men¬ tioned signs indicate that the soap has been well formed, the next step is to remove from it the waste lye, that is to sa} T the superfluous water, the foreign salts that were contained in the lye, (notably carbonate of soda) and the glycerin formed during the process of saponification. This removal is effected by add¬ ing salt, or salt soaked in water, or—better yet—a saturated so¬ lution of the same in water, or strong lye (30 to 40° B,) to the boiling mass. The waste lye, on taking up the salt, or the excess of caustic as the case may be, becomes unable to hold the soap in solution, and at the same time it withdraws water from the soap; as a con¬ sequence the latter rises to the top of the mass in the kettle, and the waste lye with the dissolved salt, glycerin and various im- Settled Soaps. 191 purities settles to the bottom. About 6 to 8 per cent of salt (calculated on the weight of fat used) is required for this pur¬ pose, the quantity depending on the amount of superfluous water present and on the kind of fats used. A pure tallow soap will thus be separated from the waste lye when the latter contains enough salt to indicate 12 to 14 : B. on the hydrometer. Cocoanut oil soap remains soluble in the waste lye until the latter is raised by salt to above 24-26° B. If salt is used it is preferably dissolved in water before add- • • ing it, as some of it is otherwise liable to remain undissolved in the soap and cause trouble afterwards. This is especially so if the soap is of a tough consistency, such as results when a good tallow is boiled with strong lye made from high grade caustic; in such cases, when dry salt was used in the first change, it has even happened that it was found still undissolved in the finished soap in the frames. The soap, boiling well while receiving this addition, will “open,” that is to say, it will coagulate slightly, and the lye sepa¬ rates from a sample taken on the paddle. When it is observed that the soap begins to open, no more salt or brine is required ; the open steam is turned off, and boiling is continued on closed steam only, until by evaporation the soap is deprived of enough water, and the waste lye has become concentrated so far, that it sepa¬ rates clear and thin from a sample of soap taken on the paddle (or trowel used in its place in some factories). The closed steam is then also turned off, and the soap is allowed to rest for say four or five hours, in order to let the waste lye settle. The effect of the salt or brine here described mav also be •/ brought about, as stated before, by using strong lye instead. Salt is ordinarily used merely for the sake of economy, as the waste lye is charged with many impurities, and therefore run away without further use (unless worked up for the recovery of glycerin). But the use of strong lye has the advantage of keep¬ ing the soap free from salt, which but too often causes soap to be “cracky” in the frames, unless it has been very thoroughly re¬ moved in pitching. When lye is used instead of salt the alkaline strength it contains may afterwards be utilized in making a lower grade of soap. Cocoanut oil soap is difficult to grain on salt, of which a large quantity would be required to separate it from the waste lye; consequently, when a large proportion of cocoanut oil is The use of lye in¬ stead of salt for graining. 192 Settled Soaps. Saving the soap from the waste lye. saponified together with other fats, a different method of work¬ ing is generally adopted, as will be explained hereafter. It sometimes occurs—with the use of stock of poor qual¬ ity—that the soap refuses to open on the addition of salt. This may then be remedied by allowing it to cool off somewhat, and if it should thereafter become weak in alkali, adding a little more lye, when it will generally separate without further trouble. It may be advisable to assist the process in this case by means of crutching. (See also under “Grease,” page 46, on this subject). Sometimes soap will not open on dry salt for the reason that water is lacking to dissolve it, in which case brine is necessary for the purpose. Some soaps naturally appear thin (cotton seed oil soap, for instance) even if they contain but little water, so that brine may sometimes be necessary, instead of salt, notwithstand¬ ing the fact that the soap has a thin appearance. The waste lye, after sufficient rest, is drawn off into a tank in which it is allowed to cool, before running it away. Any soap which it may have held in solution while still hot will then separate and may be regained, whereupon the clear waste lye is run away (or worked up for glycerin ). A dirty precipitate will collect on the bottom of this tank, and must be removed from time to time, as it is of no value. This is most easily effected by connecting the tank with the steam boiler whenever the latter is “blown off,” letting the hot water from the boiler run through the tank, thus washing away the precipitate which is quite diffi¬ cult to remove in any other manner. The Rosin Change. The waste lye having been drawn off, the rosin is next saponified by boiling it, together with the soap, on additional lye. Fresh lye is first run into the kettle, at a strength of from 18 to 20° B , and in sufficient quantity to at least stand high enough in the kettle to cover the closed steam pipe, in order to prevent as much as possible the sticking of the rosin to the hot pipes. Both open and closed steam are then turned on and, after boiling the soap alone for a short time, till it forms a some¬ what grainy mass, the rosin is shoveled in, having been previously reduced to pieces of about the size of an orange. The lye is used at say 18° B. because at this strength it combines readily with rosin. Weaker ly^e would be apt to cause frothing of the soap, would be a waste of kettle room, and would Settled Soaps. 193 interfere with the free working- of the contents, as during- the saponification of the rosin the soap must be kept “ open ” by having- an excess of sufficiently strong- lye in the kettle at first, and towards the end of the operation by adding- salt. The closed steam is used during- this chang-e to promote an even, regular boiling; the open steam serves to keep the rosin from the closed coil. The rosin used may be of light or dark color, according to the grade selected. Of course the darker the rosin used, the more highly will it color the soap, as only part of the coloring matter can be removed by boiling on lve and subsequent settling. The rosin combines almost instantly with the ly^e, which must be continually run in (at the strength above mentioned) while the rosin is being gradually added, so as to keep the soap open by the excess of strong lye always present in the first stages of this change. When nearly all the rosin has been shoveled in, the supply of lye is cut off, and some salt or brine is added into the kettle to keep the soap open, while the last strength of lye is absorbed by adding the remainder of the rosin. The object of having the soap open on the rosin change is two-fold. In the first place, it promotes easy working in the kettles and prevents the rosin from going to the bottom too readily; secondly, it helps to discharge more of the coloring matter of the rosin. The combination of the rosin (unlike that of neutral fats) with the lye is not in the least distributed or re¬ tarded when the soap is open. All the rosin having been added and saponified, the soap be¬ ing open on salt, and when the lye runs thin and clear from a sample on a trowel, the steam is turned off and the soap allowed to rest for about five or six hours, to settle the waste lye. As the latter is run away it should have no caustic strength, or at least but very little; a slight sharpness here aids to discharge more of the color of the soap, as does also the presence of some carbonate of soda in the lye. When the lye is well separated, draw it off and run it into a tank as before, to regain the soap which it holds in solution while hot. After cooling in this tank the soap is taken off and the clear lye is then run away. [For a simplified process of making this soap, strong lye at 20° to 25° B. may be used instead of salt to keep the soap open as described auove. This lye, after separating by rest, is then saved for the strength it contains, and the soap is thinned simplified pro] cess. 194 Settled Soaps. by boiling- on a little water and open steam, and “settled,” as described hereafter. Made in this way, the soap is darker and the fat less thoroughly saponified than when the more elaborate process, as here described, is employed.] Strengthening Change. The waste lye from the rosin change being run off, the soap is boiled again on lye, in order to saponify the last particles of fat and rosin still present and to wash out as much of the re¬ maining color, salt, and other impurities as possible. The salt, especially, must be removed, as its presence disturbs the opera¬ tion of settling, and later on also the framing. This process, called “strengthening,” may be carried out as follows: Weak lye, of say 6-10° B. (according to contents of water still in the soap and to steam used, closed or open), is run into the kettle, enough to cover, as before, the steam coils, so that boiling may proceed quietly, and that the rosin which may still adhere to the coil may be saponified. Closed steam is turned on, and the soap boiled slowly. The strength of this lye is reg¬ ulated on the principle that while on one hand no unnecessary water should be introduced, it is on the other hand in a close condition of the soap that the lye can best reach all the particles of unsaponified stock. As the alkaline strength is absorbed more lye of the same strength is added, and occasionally the open steam turned on for a few minutes to work the contents of the kettle through, and to remove any rosin which might still adhere to the coil. Enough lye must be added to give the soap good sharpness and to cause it to open to a very soft and large grain, in which condition it most readily drops the impurities and is most easily drawn together with water afterwards. If grained too far, by too strong lye or by too prolonged boiling, much water is required later in finishing, causing an excessively large “nigre” and trouble in framing, as will be more fully des¬ cribed in the succeeding pages. When opened, as stated, the materials should have become well saponified, and a sample, when pressed between the fingers, forms comparatively dry scales which must not be smeary. Steam is turned off and the lye given time to settle After sufficient rest the lye—which may even be weak enough to have a little soap dissolved in it without detriment, especially when very dark colored stock has been used—is drawn off and saved for its strength which it still Settled Soaps. 195 contains, On cooling-, any soap that it may have held in solu¬ tion may also be reg-ained. A different proceeding: may be adopted, instead of the An extra change, strengthening- change here described, by first making an extra change in the following manner: The waste lye from the rosin change being drawn off, open steam is turned on and weak lye, or even water, run into the kettle. Boiling and the addition of weak lye are continued un¬ til the soap becomes close and thin, and tastes slightly sharp. Then it is grained by the addition of brine, and boiled on close steam until a good curd is formed. Then, after sufficient rest, the waste lye is run away and the soap closed again by the ad¬ dition of water, under constant boiling, until it is clear and smooth. Bye of 10 to 15° B. is then run in and boiling con¬ tinued, on both open and closed steam, till the soap opens again and the lye begins to separate from the soap. Boiling is then continued on closed steam alone, till the soap forms a soft, round curd, and the froth formed at first begins to disappear. After resting for some hours the lye is drawn off and saved, as already described. •“Fi NI s HIN g” or “Settling.” This operation, also known as “pitching” or “fitting,” pro¬ gresses most favorably in large batches, as it depends greatly on the length of time during which the soap retains its heat. The object is to remove the free alkali, water, salt and other impuri¬ ties that still remain, such as the insoluble soaps formed by the combination of small portions of the fat with various impurities of the alkali, as lime, iron, etc. It is carried out as follows: The lye from the strengthening change being drawn off, the open steam is turned on slowly to warm the soap, and a little water is then run into the kettle. Boiling is thus continued with open steam, or with both open and closed steam, until the soap is quite tough and “ close,” and a sample slides from the paddle, held slanting, in large flakes, which adhere tenaciously to the paddle, so that on dropping from the latter the part still adher¬ ing draws back like an elastic band. The soap in the kettle must look bright and shiny, and should have but little sharpness. It will rise in the kettle and should be made to swell up as high as possible, which will facilitate the dropping of the “ nigre.” Only so much water must at first be added that the soap 196 Settled Soaps. does not assume the appearance here described too quickly, so that the water may be well boiled through before the operation is finished, and may be distributed evenly throughout the mass. If at the beginning of the operation it should be found that the soap thickens, it is either lacking in water and then will be sharp in taste, or it is weak in consequence of a deficient supply of lye. Accordingly water or weak lye must then at once be added, in order to bring the soap into proper consistency and sharpness. When the soap has been raised as high in the kettle as pos¬ sible the latter is covered up to keep in the heat, and the closed steam is turned on for half an hour longer, when it is also turned off; there is little danger of boiling over if properly managed, but it may be well to watch the kettle until the steam is turned off. The soap is now’ allowed to rest for a day (when it may be uncovered if the weather is warm, to cool off more rapidly if the saving of time is an object), or it remains covered to settle as long as possible. According to the size of the kettle and its con¬ struction, and to the w’eather, the cooling will require from two days to a week. The more time can be allowed for settling the more thoroughly can the operation be carried out. Genekal Remarks. Simplified ods. In the foregoing pages has been described the most usual process for boiling settled rosin soap; but different plans are sometimes adopted to suit different circumstances. For instance, the rosin may be added at once when the tallow has been saponi¬ fied, without first graining on salt. Or, on the rosin change, the soap may be kept open on alkaline strength at first, without using salt for the purpose, and finally enough rosin added care¬ fully to take up nearly all this strength, so that the soap boils in a close condition similar to that in the finishing boil already described. It may then be settled at once, without a separate strengthening change, and the boiling is thus simplified, but, of course, at the expense of the quality of the product. Another simplified process consists in boiling fat and rosin together on brine, in order to discharge as much of the color as possible, and then saponifying with lye at from 15—25° B., so that a little sharpness is left at the end of the operation. In this condition the soap is left to settle. Or again, the fat and rosin may be saponified with just Settled Soaps. 197 enough lye to make the soap perfectly neutral, cooled as if for settling, and framed in the ordinary manner. (This would of course not be a “settled ” soap.) Several other varieties of these simplified processes might be mentioned, but since they naturally do not produce as thorough¬ ly saponified and clean soap as is made by the more extended method described in the preceding pages, it is not necessary to go into further details on this line. As has been said before, rosin combines readily with car¬ bonated lye; it seems, however, that the soap formed in doing so is softer than that made with caustic lye, and the carbonic acid set free during saponification throughout the mass is a great inconvenience. Framing. When the soap in the kettle has become cooled down to about 140° F. in warm weather, or 150° F. if the weather is cold, framing of the clear soap may be begun. At the bottom of the kettle will be found a dark colored soap like mass, called the “nigre,” which amounts to about one quarter—more or less—of the whole. Above this is found the clear soap. (The utilization of the nigre will be treated on hereafter.) The clear soap, if run hot into the frames without filling, and left there to cool, will solidify in wave-like formations, causing an appearance not unlike the grain of wood, which they resemble also in that the bars of soap warp slightly in the direc¬ tion of the waves on drying. The cause of this is the crystalli¬ zation of the soap formed by the stearin and soda, from the olein soap. The soap framed in this manner would, however, remain soft until it dries considerably, and for the purpose of hardening as well as to prevent it from warping too much on drying, and to increase its detergent properties, a strong solution of carbon¬ ate of soda in water is crutched into the soap before running it into the frames. In England, where a perfectly neutral soap for all purposes is made so much of (and to a small extent also in this country) the clear soap is framed without any addition and known there as “Primrose” soap. The framing of the soap is generally done as follows: The carbonate of soda required is melted, either sal soda or soda ash being employed. Sal soda is melted by the application Unfilled soap. Sal soda filling'. 198 Settled Soaps. Soda ash. Manner of ing. of open and closed steam, to be of a strength of 33-34° B. while hot (which will be equal to 34-36° when cold). If it is to be used cold it should be melted the evening before, so as to let the sedi¬ ment settle over night and cool off. Instead of sal soda, which was formerly the purestcommercial form of alkali, many factories now use a very pure grade of soda ash, or what is known as “58% pure alkali,” of which a sufficient quantity is dissolved in enough water to be of the desired strength, as above, fram- The clear soap is pumped out of the kettle into a vessel which is somewhat larger than the crutcher, and placed directly above the latter, so that the soap will run from it into the crutcher by its own weight on opening the valve. The object of this vessel is to permit of continuous pumping while one frame of soap is being crutched, whereby not only time is saved, but the danger of the soap setting in the pipes and choking them is also averted. (Towards the end care must be taken not to draw any part of the nigre into the crutcher, as the nigre softens the soap, causes spots, and interferes with the soap taking the filling.) When soap enough to nearly fill the frame has been run into the crutcher, the machine is started up, and from 6 to 9% of the soda solution added at once. The crutcher must be sufficiently filled to prevent the soap from catching air as it falls over the rim of the inner cylinder, as otherwise it will become frothy. The soap at first thickens, but as the machine gradually runs faster and thoroughly mixes the contents, the soap becomes perfectly smooth and bright. The crutching for each frame does not require over five minutes, and as the soap cools off during this time, advant¬ age is taken of this fact to add the perfume just long enough be¬ fore running the soap into the frame to insure its thorough mixing; this avoids, as far as possible, the evaporation of the perfume. (See, also, the chapter on perfuming soaps). A sam¬ ple taken out of the crutcher, when cooled off, must be quite solid, and on cutting with a knife it must not be smeary. A clean trowel sunk into the hot soap, until it becomes heated, and then withdrawn, must have the soap closely adhering to it and thus show that it is in a “close” condition. If these con¬ ditions are properly fulfilled, the soap is at once run into the frame and will be a good marketable product when cut and pressed; nor will it effloresce on aging. The exact amount of soda solution which the soap will take without trouble may be determined by trying say 6 per cent at Settled Soaps. 199 first and crutching; if the soap assumes the smooth appearance, etc., described, the quantity added is sufficient, but if a sample taken out does not retain this appearance on cooling', then more must be added, till the soap, when cold, is satisfactory. If the soap fails to thicken after the soda solution has been added, or to become perfectly smooth and close, but on the con¬ trary opens, it is an indication that either the strengthening' change or the thinning out in the kettle for settling was not properly managed. If the soap does not adhere to the hot trowel, but leaves the latter clean and bright, it indicates also that the soap is too short, i. e ., has been separated, and is not in proper condition for framing. The only remed} r in this case is to grain the whole boil again and make a new settle, for if framed in that condition it would drop part of the soda filling in the frame, be full of cracks, and become covered with efflorescence on dry¬ ing. Only soap which is very nearly or quite neutral can be filled pro¬ perly, and if the soap had been grained too far in the strength¬ ening change, so that the lye could not settle out well, and too much water was required for thinning in consequence, the soap will not settle properly, will contain too much water, and will not be sufficiently neutral to take the filling readily. The proper temperature for framing is a matter of importance in this soap (as in most others), and should therefore be regul-. ated by warming or heating the soda solution in the ratio as the soap remaining in the kettle cools off, while the first part is be¬ ing framed. While the soap is still at about 140° F. (according to circumstances), the solution is used at about the same tem¬ perature, but with too cold soap it may be necessary to heat the filling, even to boiling. If framed too hot, the soap will be cracky on drying. Soap containing much rosin, or much water, must be framed at a lower temperature than the soap here described, say at 130° F. If for any reason the soap arrives too hot in the crutcher, cold water is circulated in the steam jacket of the machine. When the average temperature of the soap and soda solution together is too cold for framing, the mass will assume a dull ap¬ pearance in the crutcher, remain soft, and is prone to become frothy by the action of the machine. The crutcher must then be stopped and covered, and steam admitted to the jacket until the mixture is warmed up properly. For the next frame the fill¬ ing must then be heated. Temperature i n filling’. 200 Settled Soaps. Conditions gov¬ erning amount of filling. Evaporated s a 1 soda. Starch. Regarding- the amount of soda ash or sal soda to be used in framing, this has been stated above at 6 to 9 per cent of the weight of the soap, which is the proportion generally used, and the mode of preparing it has also been described. However, these statements are subject to the following qualifications : One reason why the correct proportion varies is that the soap may not have been finished perfectly neutral, or it may have retained some traces of salt. In these cases the soap will not take as much filling as a properly finished soap would stand without trouble. Another thing to be considered is the quality of the carbon¬ ate of soda used in preparing the solution. It is obvious that it cannot be immaterial whether the carbonate is pure or otherwise. Some soda ash contains as high as 20 per cent of foreign salts, while sal soda and 58 per cent of alkali are very much purer. The foreign salts do not have the same effect on the soap as the actual carbonate of soda, and more of the impure alkali would therefore be required to be the equivalent of the pure article. But on the other hand, the foreign salts in the lower grades of soda may act as a disturbing element (especially when fram¬ ing rather warm), for they will naturally exert a similar in¬ fluence in the soda solution as if they were present in the soap, and the consequence of this may very easily be cracky soap. The pure grades of alkali are therefore preferably employed in in filling. (See App. Note 15). When too much water is present (either from having thinned out the soap too far in the finishing boil, or because the soap had been grained too strongly in the previous change), part of the ordinary sal soda may be substituted by “evaporated ” sal soda, or “concentrated” sal soda, which is a carbonate having much less water in its composition than is contained in the ordinary article. This “evaporated” carbonate attracts the superfluous moisture in the soap, and is used by stirring it dry into the hot sal soda solution. The amount of it to be used must be judged by the appearance of the soap in the crutcher. One pound of it is equivalent in alkali to 2>^ lbs. of ordinary sal soda. Soap containing much rosin, and therefore apt to be sticky, and to crack when filled with sal soda alone, may also be filled with a little starch in addition, which binds the materials to¬ gether and absorbs much of the moisture, facilitating framing by preventing the separation of the materials. For a soap made Settled Soaps. 201 of tallow and 75% rosin, for instance, 9 to 10% soda solution, to which \ l /z to 2% starch have been added, may be used to advan¬ tage. (See chapter on “Filling-,” under “Starch,” page 81). Soap made of part cocoanut oil, owing to its ability to absorb large quantities of salts without separating, will not become cracky so easily as a tallow-rosin soap. Instead of sal soda or soda ash solution alone, with perhaps a little starch, many other additional filling materials may be employed for this kind of soaps, but as said before, they cause a more or less unsightly appearance of the soap on drying. For instance, silicate of soda at 35° B. may be added by crutching, from 2% upwards, as the soap will stand it, and according as more or less sal soda is added. About 2% silicate and 8% soda solution, to which 8% of talc may also have been added, are frequently used; or 8 to 10% sal soda and 5% of silicate. Still another mixture: 100 lbs. sal soda (or an equivalent weight of soda ash), 10 lbs. borax, 10 lbs. pearl ash, dissolved together, to 38° to 40° B. Add 10 to 12 lbs. starch, and use from 6% to 8% or more of this mixture, according as the soap will take it. Where no silicate or starch are used, silex is sometimes crutched in, although this material is certainly not to be recom¬ mended in a laundry soap, and it is not so much used now as formerly. The silex is first mixed with the warm sal soda before adding it to the soap in the crutcher. For further particulars on filling see the chapter on these materials on pages 79-86. Stripping, Cutting, Drying, Etc It requires from one to three days for the soap to solidify suf¬ ficiently so that it can be “stripped,” that is to say the frame taken off, if iron frames are used. In wooden frames about a week is necessary. Another day is then allowed for further cool¬ ing, and then the soap is cut into slabs and bars by the machinery described heretofore. The bars are stacked on racks for drying slightly, until a somewhat dry pellicle is formed on their surface. The drying operation is still largely conducted by simply exposing the soap to the action of the atmosphere. This requires much room, and the drying proceeds in a hap-hazard wa} 7 , ac- Different fill i n g mixtures. 202 Settled Soaps. Natui’e of nigre. cording- to the weather, but slowly at best. Some manufacturers heat their drying room by steam apparatus, to make the process at least positive. The most rapid drying is secured by the fan apparatus de¬ scribed in chapter V., which also produces a glossy skin on the soap that facilitates pressing and improves its appearance. The operation of pressing will be described in a separate chapter. The Nigee. The “nigre” is a mixture of soap, water, and various salts and impurities which are washed out and precipitated during the settling operation; there is also present the excess of alkali that was left in the kettle after drawing the strengthening lye, and coloring matter incidently introduced with the various raw materials. The formation of “nigre” in the kettle takes place as follows: The strengthening lye, it will be observed, was so strong when drawn off that it was unable to hold any soap (or at all events but very little) in solution. On diluting the remaining traces of this lye, however, as is done in the finishing change, its capacity for dissolving soap is proportionately increased, and in consequence there is formed a weak lye, holding in solution more or less soap and the salts, etc., already enumerated. This solu¬ tion, being specifically heavier than pure soap, sinks to the bottom of the kettle, taking various impurities along in so doing, thereby clarifying the soap and constituting the “nigre.” It is evident from the explanation that the more water is used in thinning the soap the more soap will be dissolved, and the larger will be the nigre in proportion to the pure soap above it. At the same time the pure soap also holds more water when the nigre is larger. Rosin and soft greases form soap which is more soluble in water containing salts than is pure tallow soap, and olein soap is more soluble than that from stearin, so that the nigre if grain¬ ed on salt will furnish a soau which has slightly more rosin and soft fatty acids in its composition and is therefore softer than the good soap in the kettle, besides being mixed with more col¬ oring matter, with insoluble soaps formed by lime, iron, etc., and with impurities generally. Still, the proportion of good soap in the nigre is very large and must be utilized in some wa y. Settled Soaps. 203 The nigre will constitute about one quarter of the contents of the kettle (more or less, according’ as the soap was settled coarsely or finely) and may be utilized in various different ways, of which those generally employed may be enumerated as follows: I. The nigre resulting’ from a batch of soap from fresh utilizing the materials that were boiled in a clean kettle is left in the latter; fresh stock is added and lye run in until the stock is saponified ; the boil is then finished as usual. The nigre which results from settling- this batch is still softer and more impure than the first nigre, and is g-enerally used, together with fresh stock (mostly of somewhat inferior quality) for a second quality of soap. This is repeated throug-h several boils of second grade soap, when the nigre is finally used for a still lower quality of brown soap, in which common fats and a small proportion of palm oil (the latter for improving- the color) may be used. The nigre again result¬ ing from settling this dark soap is saved, until from successive similiar batches enough of it accumulates to make a very low grade of soap from it. II. The nigre, after passing through two or three batches of the best soap, is separated by adding salt and boiling. A frothy soap is thereby separated, from which the salt solution is run away after a sufficient rest. The soap so separated is saved in a kettle by itself (or in frames), and when enough of it is on hand to make a batch it is boiled on weak lye and again grained on salt. The waste lye is then settled and run away; the soap receives a somewhat coarse finish, is settled and then framed for occasional use in some lower grade of soap. The nigre resulting from this settling operation is set aside for use in a very dark grade. III. The following plan will, in many cases, be found use¬ ful: The nigre is used first for the lighter colored soaps, then for the darker ones, and when it finally becomes advisable to use it up, so as to be rid of it, it is grained, the waste lye run away, and the soap washed out by boiling with plenty of weak lye, at, say, 3-6-" B., so as to remove all the salt. Then it is fitted to form a very thin grain, so that the lye is not quite clear, but con¬ tains just a trace of nigre, and time is allowed for settling. The soap so obtained contains an excess of alkaline strength, which is taken out by adding, in the crutcher, an equivalent proportion of cocoanut oil. The soap is filled with sal soda, just as in the case of ordinary settled soap, and then framed. 204 Settled Soaps. Usingscraps with¬ out remelting. IV. In some factories the nigre is “bleached,” and the kettle then charged with fresh stock on top of it, using - each nigre in this manner without making - dark soap. The bleaching maybe carried out as follows: The nigre is grained on salt and the waste lye run off. Water is then run in to close the soap, and enough lye to give a little sharpness. Tin crystals (stannous chloride, muriate of tin) are then added, previously dissolved in a little water, about 1)4 to 2 lbs. of this bleaching agent being used for every 300 lbs. of nigre, according to how much rosin it contains. Open steam is turned on and the mass boiled for 2 or 2)4 hours. When the soap is again grained on salt and the waste lye run off, the nigre will be found as light colored as the soap was from which it was obtained. It is then used as stated above, by being boiled together with fresh stock. Another way of bleaching nigres is by the use of hypochlorite of soda, a process already described under the heading of Cottonseed Foots, in chapter II. As the nigre deteriorates more and more, with each succeed¬ ing batch, irrespective of its color, it may be well to use it up from time to time anyway, to get rid of it. V. Other uses have been occasionally recommended, such as making “soap stock,” for laundries, soap powder, floating soap (taking advantage of the frothy nature of the soap result¬ ing from graining nigre), etc., etc. Considering, however, the inferior nature of the nigre, the values of the different sugges¬ tions may be readily estimated b} T the soap maker. It is useless to describe the proceeding in such cases, since they are rarely employed, and are not difficult to imagine. Scraps of Soap. The “scraps” or trimmings of soap resulting from cutting up a frame into slabs and bars are best utilized byremelting them in a special apparatus, as hereafter described. (Chapter XIV.) But where such an apparatus is not used in the factory, other expedients must be employed. One way to use them, if they had been filled with sal soda, is to add them in the kettle at the end of the rosin change, in a succeeding boil, so that the carbonate of soda may be utilized by combining it with the rosin. (If added in the kettle when saponifying neutral fats, the filling would go into the waste lye and be lost.) A more satisfactory method, which also saves the kettle Settled Soaps. 205 space, consists in adding- the scraps, cut into small pieces, to the soap in the crutcher, the latter being- used somewhat warmer than usual in order to make up for the low temperature of the scraps, and the filling- used somewhat weaker, to make up for the dry condition of the chips. This has at least one advantage, namely—that the heat used for remelting is saved, but it makes the correct framing of the new soap somewhat more difficult. (See, also, the chapter on “Remelting” and under “Cold Soap.”) WHITE SETTLED SOAP. To make a white settled soap the properties of the rosin used in the yellow soap just described are generally supplied in some other way, namely, by a proper selection of fats, as a set¬ tled soap from tallow or similar fats alone dries out strongly, and thereby becomes very hard and too difficultly soluble for practical use. Advantage is in this case most frequently taken of the property of cocoanut oil soap to retain moisture, thereby not only preventing undue drying, but also—to a great extent at least—the general discoloration to which a pure tallow soap is subject on aging. The addition of cocoanut oil also aids the settling out of impurities, as may be seen from the fact that the nigre from a pure tallow soap is much lighter in color than that from a soap in which some cocoanut oil was used with the tal¬ low. Tallow and 10 per cent of cocoanut oil furnish a good, hard, and white soap, suitable for all household purposes, and the fol¬ lowing description of making a white settled soap is based on this composition. Other fats may of course also be used, instead of the tallow, such as lard, and bleached palm oil, for instance. Grease gene¬ rally furnishes off-colored products, and cotton seed oil causes yellow spots on drying, especially if the soap is not filled. First Change. The tallow and cocoanut oil are clarified together in the same manner as stated under “ Rosin Soap,” and are then saponi¬ fied, beginning with lye at say 12° B., of which about one pound is run into the kettle for every three pounds of stock, while boiling on open steam. When the quantity of lye stated has been well boiled with i Stock for white settled soap. 206 Settled Soaps. the fats, the contents of the kettle form a homogeneous mixture, whereupon saponification is continued by running in strong lye at 25 to 30° B. which is run in slowly, under gentle boiling, so that the boiling is not interrupted, nor the soap allowed to open. If the latter irregularity should take place, it is a sign that the lye has been added too fast, and a little more water may then have to be added until the mass closes again. When the soap becomes transparent and tastes sharp, the saponification change is finished. In order to make sure on this point, a few minutes’ rest is allowed, and if the sharp taste re¬ mains on then boiling again, enough lye has been added. Other¬ wise a little more lye must be run in and again boiled through. During this change the lye must never be allowed to run in so slowly that the strength is at any time entirely absorbed, nor so fast that the soap opens. If the lye is used too strong or in great excess, the soap opens and saponification is retarded by it; on the other hand, if the soap is weak it will suddenly become thick and difficult to manage. In the latter case strong lye must be run in at once, and the soap be thoroughly crutched, while the steam is only turned on far enough to barely keep up boiling. When the paste is transparent and retains a slight sharp¬ ness after the lye has been turned off for some minutes, it is grained with salt or brine, and the waste lye allowed to settle, as described in the previous boil; or the kettle may be opened with lye, this removing coloring matters more effectively and at the same time being at times preferred in regard to the recovery of glycerin from the waste lye. When cocoanut oil is saponified it naturally has a somewhat sharp taste which is sometimes mistaken—by those not used to working with it—for alkaline strength. The first change may also be carried out by first saponi¬ fying the tallow alone, and graining it on salt as in the rosin soap described; then running off the waste lye and adding the cocoanut oil, and boiling with more lye in much the same man¬ ner as the rosin was saponified in the same boil just referred to. The weaker lye employed in this case for the tallow is supposed by some to bring about a larger yield of soap, as it is more favorable to thorough saponification. Settled Soaps. 207 Strengthening Change. After drawing- the waste lye from the first change, new lye at from 20-24° B. is run into the kettle and the soap boiled for an hour or longer, until all parts of the fat are thoroughly saponi¬ fied. The strength and quantity of the lye required for the strengthening change depends on circumstances. If the soap was not grained strongly at the end of the first change, it will hold considerable water, and a stronger lye is then used than would be proper if the soap contained but little water. Again, if open steam only is used, the lye may be stronger than when a closed coil is used for boiling, on account of the water intro¬ duced by the condensing steam. As to the quantity, about 30 gallons of lye to 1,000 lbs. of fat used will be required for an averaged sized kettle. i At the end of this change the soap should be in a soft, large curd, so as to drop the lye well; if grained too far, it will require too much water in thinning and cause an excessive nigre. The lye from the strengthening change is carefully removed after a sufficient rest, so as to free the soap from it as perfectly as possible, and is saved to be used for its strength for some dark soap. Finishing. Water is run into the soap to thin it, open steam being turned on for gently boiling the mass. The quantity of water again depends on the condition of the soap, and may be 8 to 10 gallons for every 1,000 lbs. of stock to begin with. The soap becomes close, and a sample must be smooth on the top. If it rises high in the kettle and the sample separates no lye, it is sufficiently thinned out; otherwise more water must be added and well boiled through. The soap is then allowed to settle un¬ til cooled off to about 160° F. and the good soap framed. Framing. The soap is generally framed pure, as it is sufficiently hard without filling (and in that case, if made from good stock, would answer well for “milling” into toilet soaps). The larger the frames used, the slower will the soap cool, whereby the texture will improve and the soap be harder on cutting than if cooled rapidly in small frames. But if wanted , this soap may be filled 208 Settled Soaps. Castile soap. Settled soap with¬ out cocoanut oil or rosin. —like a rosin soap—in the crutcher, with about 8 per cent soda solution (36° B.), to which may be added from 6 to 8 lbs. of borax, or other filling- desired, to each frame of 1,100 lbs. General Remarks. As the manufacture of this soap resembles in most particu¬ lars that of the rosin soap already described, it was unnecessary to repeat here all the details reg-arding- the various operations; for further particulars the reader is therefore referred back to the description of making “Rosin Soap” (page 185, etc.) It may be remarked in this connection that the true white Castile soap (so-called from the former kingdom of Spain, where this soap was originally made in very large quantities), is made by “settling” a pure olive oil soap. In this country it is imi¬ tated by making a similar article, in which the olive oil is sub¬ stituted by such fats (in various proportions) as tallow, cotton seed oil, cotton stearine, bleached palm oil, cocoanut oil, etc. The true Castile soap, as may be readily imagined, becomes extremely hard with age, and forms a slimy mixture with cold water rather than a lather. It is used mostly for pharmaceuti¬ cal and technical purposes (by silk dyers, etc.); and according to the use for which the American products are intended, its properties are more or less sought to be imitated. There are also numerous soaps brought on the market which simply trade on the good name of the original, and are made after almost all processes of soap making known to the trade, having gen¬ erally no similarity whatever to the true Castile soap. An imitation of Castile soap for manufacturing purposes is often made in this country from equal parts of tallow and cotton seed oil, settled coarsely and crutched till nearly cold, without filling. It is sold in barrels, or framed and cut like other soaps. A settled soap from tallow alone, or from cotton seed oil alone, or from a mixture of the two, may be made in the same manner as other settled soaps, but it should be thinned down only so far as to be still in a half-grained state. If it were thinned out as much as is usual in a rosin soap it would form an excessively large nigre, owing to the great quantity of water re¬ quired for thinning such a soap to that degree. The good soap would also hold considerable water and shrink very much on drying. Such soaps ma}^ also be filled like a settled rosin soap, Settled Soaps. 209 but will not take quite as much filling. If made of cotton seed oil only the soap will be rather too soft for cutting - it into bars. A somewhat similar soap as the one here described is fre- A modified pro quently made in Germany by a process not well known here, and which may be briefly described, as follows: The tallow is saponified alone, grained on salt and boiled well on fresh lye of 15° B. (over open fire in most cases) till the soap is well grained; 25% of cocoanut oil is then added and boiled until the sharpness of the strengthening - lye is absorbed, about \]/2 lbs. lye at the strength named being used for each pound of cocoanut oil. The thickly fluid soap formed by his operation is then thinned with salt water until a samp e slightly wet on cooling. The kettle is then covered, the soap allowed to settle and framed at about 190 : F. (The formation of nigre in this case is caused by the decreased capacity of the water to hold the soap in solution, when salt water is added; this action depends on the property of cocoanut oil soap of dis¬ solving in moderately strong salt water, and not enough salt water is added to entirely separate the soap.) When, in making a rosin soap by this same process much or dark rosin is used, they sometimes add the latter to the nigre of the last boil, run in a rather weak lye to saponify the rosin, and add enough salt so that the waste lye still contains some 'nigre; after settling thereafter much of the coloring matter of the rosin is got rid of before fresh fat enters the kettle. In this connection may be mentioned also the plan, some¬ times adopted, of saponifying the rosin separately by means of carbonate of soda (which is cheaper and assists in discharging color, then separating by the use of salt, and adding this pro¬ duct so obtained to the soap in the kettle). ' . CHAPTER VIII. Boiled Down Soaps. It has already been stated (page 180) that the “ boiling down” of soap is a process by which, in the first place, a pro¬ duct is made which contains less water in its composition than is commonly met with in ordinary soaps. As a consequence the effect of this operation of “ boiling down” is to render the soap harder, less rapidly soluble, and—unless the boiling down is carried very far—to produce the natural “mottle” or “marble,” which in former times served as a guarantee that the soap con¬ tained no excessive amount of water. The marbled appearance of soap that has been boiled down is caused, according to the generally accepted theory, by a process of crystallization through which the coloring matters in the soap are expelled from the white, crystalline parts (stearine soap), and become enclosed in the more slowly solidifying, non-crystalline portions (olein soap), coloring the latter by their presence. On closely examining such a soap under a microscope, it seems that the small particles of stearine soap become so closely packed together that they force the particles of coloring matter into the softer, more spongy olein soap. (It may be doubted if the term “crystal¬ lization” can be rightfully used for this phenomenon, considering that the mottle forms at so high a temperature, at which a real formation of crystals can hardly take place). In the old process of making the true Castile soap, if too much water is present, the thin consistency of the soap causes the coloring matters to settle to the bottom of the frame, and from this circumstance arose the (formerly quite correct) belief that a marbled soap was one necessarily containing but little water. This was un- Tlie mottle Boiled Down Soaps. Stock for German mottled soap. 91 9 doubtedly true in the olden times, but at present there are ways of making- marbled soaps that contain more water than was ever dreamed of in those times, even in reg-ard to their white soaps. Of the boiled down soaps there is really but one variety that is made in this country to-day to any considerable extent—one that is g-enerally known as “German Mottled.” The genuine Marbled Castile is also made by boiling- down a soap (made by saponifying- olive oil), but the soaps made in imitation of it in this country are mostly made in almost every way but by boil¬ ing- down. GERMAN MOTTLED SOAP. This really excellent soap, as orig-inally made in Germany by the oldest process known, was composed of tallow and lye made from wood ashes; now it is made there in various qualities from a variety of fats and oils, and artificial soda. The fat used principally for German mottled soap in the United States isoleic acid (red oil), which is eminently suitable for this article. Briefly stated, “ German Mottled ” is a soap which has (g-enerally) been settled, and is then boiled on “ pickle ” to de¬ prive it of water. The fat is therefore selected, and the manu- ture in the first stag-es carried out in a manner similar as in the case of the settled soaps described in the foreg-oing- pag-es, with this exception, that the composition of fats used in “German Mottled ” should be somewhat softer on an average than is used for simple settled soap, as otherwise the finished product is very apt to become exceedingly hard and brittle on drying, and to crack. These soaps are therefore best made of red oil, or cot¬ ton seed oil, or of tallow and soft grease or any similar combi¬ nation of stock, and, general^, without the use of rosin. On account of the softness and great solubility of red oil soap a smaller proportion of rosin used in connection with it, if any, is here preferable to that used in a settled tallow-rosin soap. Besides, a red oil soap darkens considerably on aging, and much, or very dark rosin, is for this reason also undesirable. With cotton seed oil, however, from 25 to 30 per cent of rosin gives a good product. Having already described in the previous chapter the saponi¬ fication of tallow, we shall base the following description of making “German Mottled” soap principally on the use of red oil, as this gives us an opportunity of noting the difference be¬ tween working tallow and working with red oil. Boiled Down Soaps. 213 First Change. The lye required for saponifying- the red oil is run into the kettle and broug-ht to a boil. This lye may be caustic lye, or (red oil being a free fatty acid), it may be prepared by dissolving carbonate of soda (soda ash) in water by the aid of steam, until it marks 21 B. when hot. This is allowed to settle for a da} 7 or two, and the clear solution run off into the kettle. Supposing a pure grade of soda ash to have been used, about equal weights of lye and red oil will then be required for saponification. Of ati impure alkali more would, of course, have to be used, as the inert salt does not take part in the saponification. [In case carbonate of soda is used, carbonic acid is evolved during boiling, which is danger¬ ous to inhale in considerable quantities. As it is heavier than air, some provision must be made to carry it off therefore; on ac¬ count of its weight it will not rise like steam, but, although in¬ visible, remains near the floor, so that it is best got rid of by opening the doors of the kettle room to let it escape into the atmosphere.] In the boiling lye 25 to 30 lbs. of salt (according to purity of lye) may be dissolved for every 1,000 lbs. of red oil, as an additional safeguard against “ bunching.” The lye being at a brisk boil, the red oil is run in and good boiling kept up. If boiling is allowed to become slow, lumps are liable to form which are difficult to dissolve again; and as the fatty acid combines very readily with the alkali, the operation of saponifying pro¬ ceeds most rapidly and easily if the red oil is run into the kettle already somewhat heated. For the same reason it is advisable to run the oil into the kettle over a piece of sheet iron, so ar¬ ranged that it breaks up the mass in a spray-like manner, in¬ stead of running it in in a thick, solid stream. After all the fatty acid has been run into the lye, boiling is . continued for an hour or more, until all is thoroughly saponified, and the soap has become separated from the waste lye. If cotton seed oil, soft grease, etc., are used instead of red oil, the first change is of course conducted in the ordinary manner, as has been described under “Settled Soap.” The reversal of the process (/. ^., running the fatty matter into the lye, instead of vice versa , when red oil is used) is generally adopted because the ordinary mode of conducting the saponification of neutral Method of saponi' lying red oil. Precautions when soda ash is used*- Means of prevent' ing bunching. 214 Boiled Down Soaps. fats would result in an aggravated case of “ bunching ” when fatty acids are saponified. ******** [The waste lye may be run away after sufficient rest to settle the same, and in case any rosin is to be used in the soap, it may then be added for saponification, just as in making an ordinary settled rosin soap. As said before, “ German Mottled ” is ordi¬ narily made without rosin, but there are some manufacturers, especially those who use other stock than red oil, whose German Mottled soap contains about 25% of rosin to each 100 lbs. of fat. The saponification of rosin having already been described, we will here give another mode of working which maybe adopted— to suit the opinion of the soap-maker—according to the purity and color of the stock used. This method is as follows : Run into the kettle (without having run off the waste lye) about 520 lbs. of caustic lye at say 35 B. for every 1,000 lbs. of rosin to be used. Then add the broken rosin. The exact strength of lye most practicable to be used in this case cannot be given, as this depends on whether open or closed steam, or both, are used for boiling and on the quality of the rosin, and particularly on the amount of waste lye in the kettle. If only closed steam is used the quantity of lye named may have to be diluted with water. The lye is here used very strong on account of the large quantity of water contained in the kettle when the waste lye has not been previously run off. When all the rosin has been added the soap should no longer be open, but rather in the condition of a soap thinned out in “settling,” as it will then be more readily saponified. After boiling well when the rosin has been added, the soap is grained with salt and the waste lye drawn off after sufficient rest. The soap now is practically in the same condition as it was in the boil of settled soap after the rosin change, only it is softer on account of the softer stock used. It may now be repeatedly drawn together with water, or better with weak lye, and grained with salt to wash out the impurities as much as desired.] ******** When the stock is thoroughly saponified the soap is grained with salt, and one or two additional changes are given to im- improve the color and consistency, after which it is boiled down, as described below, or instead it may be first settled. Boiled Down Soaps. 215 Settling. The thoroughly formed soap may now be “boiled down” at once, but for a first-class article, for improving the color, or wnen dark stock has been used, the soap is first thinned with water and allowed to drop the nigre, whereby it is clarified, and the free alkali removed, which is quite as important in this as in “settled” soap. This process has been described before, and need not, therefore, be repeated here; it may be remarked, however, that the finer the soap is settled the larger will not only be the nigre, but also the proportion of water in the clear soap, and the longer time will then of course be required for the soiling down. A short settle only is, therefore, usually made for German mottled soap. Settling- not abso lutel y necessary Boiling Down. The clear soap, if it had ueen settled, is pumped off from the nigre through a strainer into a clean kettle, into which the “ pickle ” has previously been run (or if the soap was not settled the pickle is simply run into the kettle), and closed steam is turn¬ ed on. In regard to the proper composition and strength of this pickle much diversity of opinion exists. As to ttie composition : The pickle may consist simply of salt dissolved in water. Boiled down on this the soap will lose part of the water it holds, will mottle very nicely, and will form a sat¬ isfactory product; only it will have, on solidifying, a dry, brittle texture, which is not at all desirable. To obviate this drawback carbonate of soda (soda ash) is frequently added to the salt water to form the pickle. The texture of a soap boiled down on a pickle consisting of half salt and half soda ash solution is perceptibly better than if boiled on a salt solution alone, but here the trouble is that the traces of carbonate remaining in the soap will cause the latter to effloresce on drying. According to the composition of the pickle the texture may, therefore,be improved, at the ex¬ pense of appearance. As to strength : When boiling the soap on pickle the latter tends to become more concentrated by the evaporation of water, but at the same time it withdraws water again from the soap. In this manner it is possible to boil on pickle until the soap has lost considerable water, and yet the pickle itself will be of the same strength as at the commencement of the operation. It is obvious, however, that the proper strength at which the pickle \ 216 Boiled Down Soaps. Saving boil down. is first introducer! depends greatly on various circumstances. A soap may have been more or less finely settled and consequently contains more or less water to be evaporated. The same is true in regard to the kind of stock (and propor¬ tion of rosin, if any, used). Again, the arrangement of the steam coil and shape of kettle may be such as to require a greater or smaller quantity of pickle; if a large quantity is used it should not be so weak, in ord":r not to introduce too much water with it. A finely settled soap therefore requires stronger pickle for boil¬ ing down in a reasonable length of time than a soap which con¬ tains but very little water to be evaporated. Besides, soap makers who have had long experience in making this soap do not agree in this respect in their opinions, even under the same con¬ ditions regarding stock, etc. The proper strength of pickle for this purpose is variously named at from 8° to 20 B. (and by some even up to dry salt). The stronger the pickle the more rapidly will the operation be finished. The soap and the pickle made b} T dissolving salt alone, or salt and soda ash, in water, to a strength of from say 14 to 18 3 * B., are boiled together on closed steam, and the progress of the operation is closely watched. The appearance of the soap and the strength of the pickle is carefully observed from time to time, as tlm boiling proceeds, and after making a few boils of a given composition as to fat and rosin the soap boiler will have gained the necessary experience and correct judgment in the matter, which can only be acquired by practice and intelligent study. The mottle—formed by impurities of the raw materials in¬ closed in the non-crystalline portions of the soap—can only form when the hot soap has a certain degree of fluidity. It will develop strongly if the soap contains much water; in other words, if the mottle is too pronounced the soap has not been boiled down far enough. If boiled too far, on the other hand, the mot¬ tle cannot form at all, as the lack of water then renders the soap too thick to allow of proper crystallization in the hot soap by means of which the mottle is to be formed. The salt used in boiling down supplies the necessary mobility of the mass to permit crystallization. A method, not exactly to be recommended, but sometimes adopted in order to save boiling down so far, is to boil down as much as desired and sifting some finely ground, pure soda ash into the soap (in the crutcher). The soda ash absorbs the sur- Boiled Down Soaps. 217 plus of moisture and acts as filling*. No special proportion of soda ash is necessary to be observed, as it is not likely to effloresce (as it would certainly do in the case of settled soap, unless used just in the right proportion). F NAMING. When boiling* has proceeded to a point judged to give the proper mottle, a rest of several hours is allowed to separate the pickle, and the soap is then ready for framing, which is carried out in the same manner as in the case of settled soap. In small iron frames the soap cools quickly and shows but little mottle; if a more pronounced mottle is desired, large wooden frames are used. Filling might also be added, if desired, but generally boiled down soap is framed pure, as there is no real benefit regarding the quality of soap in boiling down if filling is to be added. If the stock used in this soap was not thoroughly saponified it will have a tendency to retain an admixture of some of the pickle, and thereby cause trouble in the frame. Pressing. On account of the “short” texture of the soap it is not press¬ ed in the ordinary manner, but merely cut in bars and stamped on the sides with a simple stamp. Potash lye used for part of the soda lye, especially if soda ash was used in the pickle, has the property of improving their texture so much that the soap so made can be pressed in the ordinary manner. General Remarks. In order to avoid unnecessary repetition, only the considera¬ tions peculiar to boiled down soaps have been mentioned in detail in this chapter;' for further particulars refer to the chapter on settled soaps. Some additional practical points are contained in the following somewhat different description of the making of German Mottled, as carried out in some factories: Nigre left over from settled soap can be used to start the boiling; it should be grained out with salt and the spent ly r e re¬ moved;* then run into the kettle about 1,000 lbs. of 8 to 10° salt water for each 20,000 lbs. of soap to be made. Bring the salt water and nigre to a boil, then run in the stock and lye at 30 to 40 slowly, so that the soap is kept just open enough that it would 218 Boiled Down Soaps. not drop a nigre if allowed to settle. Should the soap at any time be too open so that the stock will not combine with the lye, one may either run in water, or put in some of the rosin intend¬ ed to be used anyway, or simply let the kettle rest for a time till the soap takes up the lye again. When all the stock has been run into the kettle and saponified, the soap should run off the paddle in large, soft flakes, separate from the lye which should hardly have any strength in it. To prevent the soap from closing up entirely it may be necessary to add salt toward the end of the boiling. If rosin is used it is generally put in after the grease or tallow is saponified. After running off the spent lye, water is added—enough that the soap will drop a small nigre,—or salt water and some lye is used and boiling continued for 2 to 3 hours in a slightly open state; care must be taken not to get foamy soap by running the water in too fast, as this would delay the finishing of the soap later on. If ilie method of taking out a small nigre is adopted, the latter is run out of the kettleand the remaining soap boiled with salt water of 14-16°; then turn off steam and let it rest in cold weather for 4 to 5 hours, or in summer over night. When the soap has cooled to ISO'' F., pump it to the crutcher and add from 10 to 15 lbs. of soda ash (sifted in to prevent lumps). This method does not produce a good mottle and the soap is somewhat liable to whitewash. Silicate, mineral soap stock, and even silex has been crutched into such soap. Instead of taking out a nigre, as mentioned, the soap may be given 2 or 3 washings with salt water and finally finished by adding enough salt that the spent lye indicates 10- 14 B. The spent lye must be stronger in proportion as the amount of oil or rosin in the stock is larger. The hotter the soap is framed, the larger will be the mottle; the frames should be covered to prevent the surface from cooling too quickly. Wood¬ en frames of 1500 to 2000 lbs. favor the mottling. As German Mottled soap is too heavy to pump out of the kettle, it is con¬ venient to have a 4 or 5-inch cock valve at the side of the kettle, above the line of spent lye, as the soap will not run through a swing pipe. In small factories that have no remelter, the scraps from settled rosin soap can be used in place of rosin in German Mottled and any sal soda that goes into the spent lye can be re¬ covered in the next batch by boiling with red oil or rosin. If cottonseed foots are used, these have to be saponified separately and washed repeatedly or settled before the rest of the stock is Boiled Down Soaps. 219 mixed with them; it is also possible to make a pretty fair article from cottonseed foots alone and 10 to 20% of rosin, but as such soaps dissolve very easily, they can be greatly improved by the addition of 20% of tallow. * * * * * * * In this place it may be proper to briefly state how the gen¬ uine Marbled Castile soap, also known as “Marseilles” soap, is made in European countries. Olive oil (from the second pressure of the fruit), with or without the addition of other oils, is saponified with lye at from Gemune , r J soap, 10 to 20° B. Coloring mattei is then added, such as copperas (sulphate of iron), which, together with the sulphur compounds either present in the crude soda or otherwise added afterwards, causes a greenish black color by the formation of ferrous sul¬ phide. The marble formed by these materials changes to yellow on exposure to the atmosphere. The soap is grained on strong lye, which contains considerable salt in solution, and the waste lye is then run off. It is then once more boiled on strong “salted” lye and the waste lye drawn off again. Fresh lye of 22 to 25° B. is then added and the soap boiled until saturated with alkali and strongly boiled down. A little water is then carefully added to bring the soap to the right condition for marbling, or successive portions of lye, gradually decreasing in strength, are used for the same purpose. The soap is then run into large wooden frames and left to crystallize, in order to form the marble. (The coloring matters collect in the non crystalline portions.) For white castile soap the process is the same, but omitting the coloring, and thinning the soap for “settling,” first with lye at 6 to 7° and then with still weaker lye, and at last with water. Of course there are variations from this process, as well as in making all other soaps. The appliances and lye used in the foreign countries are very different from those used in the United States. The lye is still made to some extent from kelp, or more frequently by causticizing soda ash. Differently prepared lyes are used for different operations, and the boiling of a batch of soap over the open fire still used there, and the many changes of lye, generally take from three to four days. Imitations, resembling the genuine article more or less, are mostly made of cottonseed oil and some tallow. It will be noticed that the mottle is produced from the same f Castile 220 Boiled Down Soaps. \ cause in true Castile soap as in “ German Mottled,” onl} r the con¬ ditions required for mottling are brought about in different ways, for while in the former the soap is boiled to a grain and then thinned with lye or water, German Mottled is made by boiling on pickle a soap already containing too much water. In order to make the mottle more intense, coloring matter may be added to the soap. Soaps that have been boiled down immediately after saponifi¬ cation, without settling, invariabl} 7 contain some free alkali. For this reason sulphate of iron, which was formerly employed as coloring matter in such soap, was added in such a manner as to combine with the free soda, thereby setting the iron free to form the marble and also neutralizing the free soda present. The ox¬ ide of iron and other similar pigments now generally used do not possess this neutralizing action. WHITE BOILED DOWN SOAP. If a hard white soap is to be made from soft materials, such as cotton seed oil as the only stock, it requires boiling down in order to overcome the natural softness of a pure cotton seed oil soap. Such soaps are made but little at the present time, owing to the relative prices of fats, oils and rosin. Their manufacture may be briefly described as follows : (As was said in the description of cotton seed oil,this stock, when used in boiled-down soaps, has not that tendency of caus¬ ing yellow spots, as in settled soaps.) First Change. The oil is run into the kettle, along with twenty gallons of water for each 1,000 lbs. of stock. Open steam is turned on and lye at 15' B. run in. When saponification is approaching its completion, the strength of l ve is increased to 20 B. The lye should be made of high-grade caustic and plenty of time allowed for saponification, as cotton seed oil combines less readily with alkalies than other oils and fats. When the soap is well formed and has a sharp taste, it is grained with salt in the usual manner, so that the clear lye separates from a sample on the paddle. Strengthening. The spent lye is run off and open steam turned on. Water is run in during good boiling till the soap is smooth and bright Boiled Down Soaps. 2">1 and has the appearance of a soap ready for settling-. Fresh lye is then run in and boiling- continued until the soap beg-ins to open ag-ain. The streng-th of this lye depends somewhat on the amount of water previously added for thinning-, on the steam—whether closed steam is used tog-ether with open steam or not—and also on the judgment of the soap boiler. A strong- lye would finish the operation more rapidly, but weaker lye would permit of long- er boiling- before the soap becomes grained, and long- boiling-, as already stated, is required for thorough saponification, especially for cotton seed oil. When the soap beg-ins to open, salt is added to assist in graining-, so far that the clear lye separates. Boiling Down. The lye is run off ag-ain and saved for its streng-th. Pickle (made in the manner explained under “German Mottled” soap) is then gradually run in under constant boiling. When the soap has been boiled down like the German Mottled described, steam is turned off and the pickle allowed to settle. Framing. Frame in the manner as in the case of the “German Mot¬ tled ” soap. CHAPTER IX. Eschweger Soap. While in this country the “settled” soaps are by far the most prominent, and the “ boiled-down” soaps constitute nearly all the remainder of those made by boiling - , yet there are pro¬ cesses of soap-boiling - in which neither of these operations are employed. Of this class, for instance, are the “run” soaps * already referred to, which were made largely, especially in for¬ mer years. Another variety also coming under this head is a soap sometimes made here in imitation of Castile soap and known in Germany as “ Eschweger,” which was first made in 1846 by a firm of German soap-makers (Dircks & Thorey). The quan¬ tities of these and similar soaps made in this country at the present time are not so large as to require on that account an extended description of their manufacture in these pages; but, inasmuch as it affords an opportunity to show the manner of working under different conditions, they may be included to some advantage. In making most of the better grades of these soaps advan¬ tage is taken of the property of a mixture of tallow and cocoanut oil to saponify readily with strong lye, thereby furnishing a soap containing a comparatively small amount of water, without the necessity of separating the waste lye. At the same time the foreign salts introduced with the lye—which are run away with the wast lye in the ordinary manner of boiling, but remain in the soap in the present case—do not exert their usual disturbing influence when cocoanut oil is largely used together with the tallow or other similar fats. (In fact, a pure cocoanut oil soap requires an excessive quantity of salt in order to separate it from 224 Eschweger Soap. the waste lye, but will appear hard on drying- even if an amount of salt solutions is present which would entirely separate a soap made of ordinary fats alone). In consequence of this latter property, some very high adult¬ erated soaps are made by saponifying fats composed largely or wholty of cocoanut oil and adding to the soap considerable quantities of various salts dissolved in water, stock for Each- “Eschweger” is a marbled soap, made by saponifying tal¬ low and soft fats, together with about one-third of their weight, or more, of cocoanut oil. Owing to the properties of the latter oil, such soap, in absorbing considerable salt solutions, thereby becomes of a peculiar consistency, while hot, which causes crystallization, and thereby the formation of “marble” or “ mottle,” on cooling in the frame; at the same time, it holds much more water than one that has been mottled by boiling down a soap made entirely of soft fats. The fat used may be equal parts of tallow and grease, be¬ sides cocoanut oil, to one-third of their combined weight, or the grease may be substituted by cotton stearin, or cotton seed oil, or any similar combination may be used. I ndireet method. The tallow and grease may be saponified alone at first, grained, the waste lye run away, and the soap so obtained then boiled together with the cocoanut oil and the lye required for the latter and the required salts; but generally the following plan is adopted : The fats are clarified together by boiling on open steam, ■ >.ieci method. an( j the water formed and the impurities drawn off after settling. They are then saponified by slow boiling with lye of an average strength of say 25 : B., and the quantity of lye is gauged so as to have the soap very nearly neutral at the end of the operation, as there is no separation whatever of waste lye. All that goes into the kettle also goes into the soap (excepting, of course, a certain amount of water removed by evaporation). The lye should be used as strong as circumstances will per¬ mit, since any surplus water can only be removed through eva¬ poration by boiling, which is very difficult unless open fire is used for making these soaps. For this reason the tallow is in some factories saponified alone at first, with weak lye, to insure perfect saponification, che waste lye then drawn off, and the cocoanut oil added and saponified with stronger lye. This soap, when well formed in the kettle, must contain Eschweger Soap. 225 considerable carbonate (or silicate) of soda and common salt, Saits required for so that it may become sufficiently “short” to permit the forma¬ tion of a mottle. These salts are added either when saponifica¬ tion is nearly complete, as described below, or the presence of the carbonate may be insured by using 1 low-grade caustic for making the lye, and the salt be added afterwards. During sa¬ ponification sufficient lye ahead should always be in the kettle (until near the end of the operation) to insure against undue thickening of the soap, which is especially liable to occur if tal¬ low only is used together with the cocoanut oil. When weaker stock, such as cotton seed oil is used, there is less danger of this occurring. Towards the end of the saponification the physical character of the soap must be carefully watched, and the necessary appear¬ ance brought about by various additions, according to circum¬ stances, as follows : If the soap formed is thin, and a sample set on glass has a signs of properly gray ring around it, has a dull appearance and sharp taste, it indicates an excess of lye, and in this case enough cocoanut oil must be added to take out this surplus strength. If the sample is thick, glassy, and tough while hot, and soft on cooling, and appears heavy, the steam escaping by forcibly “puffing” through the mass, more lye is required. If it is soft on cooling and yet sharp, more water must be added, as the lye has then been too strong to combine properly. If the soap boils up high and thick, and a sample is ten¬ acious on the trowel, water must be evaporated to shorten it. If it is very clear and tough, and a cold sample is very stiff and rubber-like, salt or brine must be added, according as more water may be needed. If the soap contains too much salt, more cocoanut oil and lye will have to be added. Too much salt makes the soap rough and brittle, and if the excess is very great, may even cause it to settle. A properly finished soap of this kind is clear and has a bright surface; the steam of the evaporating water escapes from numerous places all over the surface (called “roses” in Ger¬ many, owing to the similarity of the formations to this flower) and a sample on the paddle must have enough consistency while still hot not to spread out very much; when sliding off the in¬ clined paddle it must break off short, and the paddle can be seen 226 Eschweger Soap. Proper quality of lye for Esch¬ weger. in places between the clots of soap; a slight sharpness should also be apparent. The lye used in saponifying the fats may be of high-grade caustic at first, and the required salt and carbonate of soda added after the materials are thoroughly combined, or the salts may be added from the start. A close study of the lye used is necessary in making this soap, and careful observation and con¬ siderable practice are required before it can be made with uni¬ form success. The presence of various salts is of far-reaching effect, and, unless the nature of the lye used at the outset is well understood, it will be next to impossible to form a correct idea of what salts must be added. If too little lye or salt is used, the soap will be soft and tough, instead of short, thus making it spotted throughout, in¬ stead of mottled, if framed in that condition. If too little water is used (or the soap evaporated too much) it will also be spotted; with too much water the mottle will form badly, or the soap will even separate a nigre. The presence of too much salt causes the soap to feel wet and cold while fresh, the mottle has a bad ap¬ pearance, and on drying the soap effloresces strongly, and be¬ comes rough and brittle. If a very caustic lye has been used at first, the apparent sharpness sometimes disappears when the salts are added, thus indicating that the fats were not fully saponified. In such case, more lye must then be added. If very* caustic lye has been used, solutions of carbonate of soda (sometimes silicate of soda) are added during the boiling, or the lye is made at once by dissolving 20% of soda ash with the high-grade caustic. As the various foreign salts are unable to form a chemical combination with fat, they merely contribute to give the soap the required mobility to permit crystallization (and consequent mottling) in the frame; they also prevent the finished soap from drying out too rapidly, and, of course, also increase the yield of soap. As was observed under “ boiled-down ” soaps, a pure tallow or olive oil soap must be brought into proper condition (/. its toughness reduced) by traces of salt introduced in the boiling- down operation in order to enable the stearate of soda to crystal¬ lize and form a mottle; at the same time, such soap holds but very small quantities of salt. Pure cocoanut oil soap, however, is quite different, for it forms a tough solution even in the pres- Eschweger Soap. 227 ence of quite considerable amounts of salt and water, of which a large quantity is required to cause the right consistency for mottling - —so much, in fact, that a mottled soap made from cocoanut oil alone could scarcely be referred to as “pure” soap in the true sense of the word. Thirty to thirty-five pounds of cocoanut oil to 100 of tallow, or similar fats, furnishes a good product which is much liked in some localities, and forms a beau¬ tiful mottle. A soap having very little sharpness, only little water, and a correct proportion of foreign salts, inclines to a large mottle. A smaller mottle results if the soap is somewhat sharper and contains somewhat more water, provided again that sufficient foreign salts are also present. No hard and fast rule can be given, what kind and how much salts to add; a trial will determine this, according to the composition of the fats and lye and the nature of the soap intended to be made. Ordinarily, lye made from low-grade caustic is used to supply the necessary carbonate, and the final corrections made with salt dissolved in water. Many, however, prefer to use high-grade lye for saponifica¬ tion, adding from 15 to 20% silicate of soda, either at once or after the materials have joined; then the soap is shortened by adding say 3% of soda crystals, and the final correction is made with a solution of common salt, until the required appearance in the kettle indicates that the soap is well made. Carbonate of soda —either present in the lye, if made of low- grade caustic, or added afterwards—causes a beautiful mottle and a high yield of soap. But if used as the only salt, the soap will incline to effloresce or “ whitewash,” especially in winter. Carbonate of potash, substituted for part of the soda, avoids, or at least decreases the latter difficulty, but the marble formed will be less beautiful. Common salt causes a very fine mottle, but the soap will bind less water and the yield will be correspondingly less from a given amount of fat. Silicate of soda thins the soaps, and if used, less of the other salts must be employed, so that there is really no gain in using it for this soap, except in that, while the yield is not as large at first the soap also does not dry out as much afterward. When it is employed for this soap the lye should be more caustic than when sal soda is added instead, and the soap should have a slight Large and small mottle. Effect of various salts. 228 Eschweger Soap. vOloring matter. Framing. Boiling by steam. sharpness to guard against the silicate crystallizing out. As high as 30 per cent may be worked into the soap, but 15 to 20 per cent gives a better product and is safer against irregulari¬ ties in boiling. (Soaps of similar composition as to fats—not mottled—are sometimes filled by boiling in this manner with as much silicate—diluted previously by boiling with water—as the weight of the fats used.) The less cocoanut oil enters into the soap, the less water and salts must of course be added, and the smaller will be the gain in soap. When the soap in the kettle shows by the appearance de¬ scribed that it is in the right condition, the desired color (cop¬ peras, ultramarine blue, Indian red, etc.) stirred into boiling hot water to which a little salt has been added, is put into the soap, and well boiled through with open steam until the color is uniformly distributed. The salt is added to the color in order to prevent it from clotting together; strong lye might be used instead if the con¬ dition of the soap is such as to make it preferable. It is well to take a sample of the soap out of the kettle and see if the color mixes with it evenly; if not, more salt must be added. The soap and coloring mixture should both be as hot as possible, in order tu be readily mixed. The amount of coloring matter to be used, it must be under¬ stood, has no effect on the quantity or formation of the mottle; it only affects the intensity of its color and must be gauged ac¬ cordingly. 8 to 10 lbs. of Venetian red to an ordinary frame will produce a good effect. Other colors, which may'be used in proportions according to their nature, are Indian red, ultra- marine blue, ivory black, etc. This finishes the boil, and the soap is run into the frames, where it is crutched for a short time and covered up to keep it warm. In the course of three hours, if the marble is seen form¬ ing, the frames are uncovered and the soap allowed to cool. Wooden frames are best employed in this case, in order to avoid chilling the soap on the sides. This soap is made mostly (in Germany) over an open fire, but this affects its color disadvantageous^, and the soap may be boiled as readily with closed steam at a pressure of 3 to 4 atmos¬ pheres by managing the lye so that no excess of water is present that requires evaporating. Eschweger Soap. 229 In making- this soap a record should be kept of the grade of caustic used and the quantity and kinds of salts added; these notes will then serve as a g-uide for the next batch until more practice has been obtained. If the soap mottles properly, but effloresces on drying-, the lye for the next boil should be used more caustic, and more potash and salt used instead of carbonate of soda. BLUE MOTTLED OR E5CHWEQER III. A soap made as described, of about one-third cocoanut oil and two-thirds of other fats, with a yield of 200 to 215 lbs. of soap from 100 lbs. of stock, is considered as Eschweg- soap proper. If, however, the fat used consists nearly all or entirely of cocoanut oil or palmkernel oil, and the soap is shortened with various salt solutions until it is in proper condition to form a mottle, the yield will be increased to 300 to 350 per cent and more. Such soaps, which were first broug-htout in Eng-land and whose method of manufacture was g-uarded as a secret for about ten }^ears, are hardly ever made in this country, but are quite well known in most other countries where they are variously sold as “blue mottled,” “Eschweg- III.” etc. They are g-enerally con¬ sidered still more difficult to manufacture with uniform success than Eschweg- soap proper, and in most cases are the dread of those to whose lot it falls to be oblig-ed to make them, for all are agreed that these soaps require very much attention and patience, and even then will be failures at times in the hands of the most experienced. We will briefly describe the averag-e process; as there is a very larg-e number of different proceeding's in vog-ue: Tnese soaps are made most frequently by half-boiling, the fat being- saponified at a temperature of about 190- F. and the soap formed in the course of several hours’ rest in the kettle is then filled with the necessary salt solutions. However, boiling- the fat and lye before filling- until thoroug-hly saponified would prevent many failures in the process, as they are most common¬ ly only the result of free fats being- present, and soap so made would dry out less than when the stock had not been perfectly saponified. For the proper formation of the mottle in these soaps every soap-maker adheres very closely to certain proportions of materials which he has found by experience to g-ive the desir¬ ed result, and at the close of aboil carefully watches small sam¬ ples taken from the kettle, to see if any corrections are required. \ Definition fb Eschweger III* Boiling vs. boiling. 230 Eschweger Soap. Both palmkernel oil and cocoanut oil lend themselves well to the manufacture of these soaps; the latter especially permits of high filling and calls for slightly more lye and salt solution. The general proceeding is the same for either oil. The following formula will serve as an example: 100 lbs. cocoanut oil. 130 lbs. caustic soda lye 24 ~ B. 20 lbs. sal soda. 42 lbs. salt water 23° B. 20 lbs. potash solution 30° B. The cocoanut oil is saponified with the lye at a temperature of 190° F. and when the materials have joined, some of the salt water is added, enough to prevent thickening. (Or the fat may be saponified by boiling, in which case the water lost by evaporation must be restored, and the salt solutions are then rapidly crutched in when the soap has cooled down somewhat). Next the potash solution, then the sal soda, and lastly the remaining salt water is crutched in and the temperature main¬ tained for some time at about 200° F., covering the kettle and occasionally crutching through. 1)4 ounces of ultramarine blue are then dissolved in 4 lbs. of water to which 4 lbs. of silicate of soda and 1 lb. 25° B. caustic soda lye are then added. A small portion of the coloring mixture is added to the soap, and samples taken. (Or a 20 lb. sample of the soap is taken and some color added for the test, before coloring the soap in the kettle.) If the silicate is observed to crystallize or form flakes, a little more lye must be very carefully added to the coloring solution until it will mix easily and uniformly with the soap. The kettle, after coloring, is covered for an hour, when samples are taken out. If the soap is then uniformly colored blue, it has too much strength, and some cocoanut oil must be added, and time allowed before another sample is taken out. If the mottle has, on the other hand, been formed rapidly and in long streaks, the soap is weak and requires a little more lye. When samples appear satisfactory (they should be preserved for comparison with later batches), the mottle appearing in small dots, the soap is framed at 165 to 170° F. and the frames kept covered for the first hour or so. While the soap cools down to this framing temperature, it is ad¬ visable to have a bucketful of the soap cooling off separately, so as to judge by it if it is safe to frame the batch, without crutch- Eschweger Soap. 231 ing it up first; in large frames the mottle will then be still prettier. The frames used have a capacity of from 1,200 to 2,000 lbs. A good way to judge whether the soap is right for mottling, is to take out three or four samples of 10 lbs. each, and adddif* ferent small proportions of cocoanut oil to the samples, and cover up for half an hour. According to the mottle formed in this time in the different samples it may be seen whether oil should still be added into the kettle, and how much. If the mottle forms in the frames, but drops to the bottom, it may be brought up by crutching, provided the soap has not yet cooled below about 14CG F., as it will form again. A weak soap mottles most readily, but inclines most to dropping the mottle in the frames; it is therefore best, when judging of the samples, not to go entirely by the most beautifully mottled sample. A somewhat strong soap forms a smaller mottle which is not liable to drop, but sometimes requires to be covered in the frame for several hours in order to prevent a bluish tint in the portions in¬ tended to be white. Another formula is as follows: 300 lbs. palmkernel oil are saponified with 360 lbs. 20° lye; there is then added, under brisk boiling, a filling mixture consisting of 70 lbs. 25° soda ash so¬ lution, 70 lbs. 25° potash solution, 17 lbs. 20 potash lye, 120 lbs. 20" salt solution, 80 lbs. water; the kettle is then covered and left at rest; samples are then taken to test for mottling and, if satisfactory, the coloring is added as above. As palmkernel oil varies somewhat, it may be necessary to increase the lye from 360 lbs. to 375 and even more. In hot weather, when it might happen that the soap settles, owing to being liquid too long, it is advisable to have it somewhat sharper in strength than in winter. For the benefit of readers in foreign countries where these soaps are made, we append, from the notes of a soapmaker who has made them extensively, the following table of proportions of materials which have proved satisfactory for the yield indicated in each case : Palm Kernel Oil.100 100 100 80 60 parts. Cocoanut Oil. — — — 20 40 “ 20° B. soda Lye.120 120 120 130 134 “ 33 c B. Potash Solution. 45 53 80 90 110 24° B. Brine. 55 70 90 120 143 “ Coloring. 5 7 10 10 13 232 Eschweger Soap. Genei'al remarks. (The coloring’ is composed of 4 parts 38°-40° waterglass, 4 parts water, 1 part 20° B. lye, one-tenth part Eschweg red or blue, or for grey, half blue and half black.) One other formula, among - hundreds of similar ones, may be here briefly mentioned, although it does not properly belong to boiled soaps: 100 lbs. cocoanut oil at 190 c F., into which 50 lbs. talc are stirred; add 112 lbs. soda lye 20 c B. When saponified, add 3 lbs. salt, dissolved in 10 lbs. water, and next 40 lbs. water glass, mixed with 10 lbs. soda lye 36 c B. The manufacture of these soaps depends less on the exact formula used than on its proper manipulation, and considerable experience is the most essential feature in making them. Accord¬ ing to the proportions of the ingredients employed, a soap will form the mottle more or less rapidly, and the frames must be adapted in size to correspond. Small wooden frames of about 500 lbs. capacity are best adapted for soap which forms a large mottle, and rapidly; such soap is framed at about 145 F., and should contain more salt water in comparison to soap which is run into large iron frames (up to, say 2,500 lbs.) to form the mottle more slowly. The latter should contain weaker and more carbonated solutions, and less salt water, and may be framed warmer than the quickly mottling soap. The several solutions mentioned for filling should be made sometime before use, so as to permit their settling where¬ by a whiter ground of the soap is obtained. They must be made from raw material whose composition (purity) the soapmaker is familiar with, as unsuspected impurities have been the cause of numerous failures. For soaps which are not to yield more than 350% some tallow is used with the cocoanut oil, as this favors the rapid mottling which is necessar} 7 when small frames are used. Cottonseed oil may also be used, in place of tallow. Cocoanut oil requires, in this class of soaps, more lye and salt solution than does palmkernel oil, and consequently gives a greater yield. A MODIFICATION OF ESCHWEGER. A soap similar in character to the “Eschweger” described Eschweger Soap. 233 but boiled in a manner approaching- nearer to the methods more usual in this country, is made as follows : The fats are selected and clarified in the same manner as for Eschweg-er. They are then saponified by running- in lye under constant boiling-, until the soap acquires a sharp taste which it retains on boiling- for a few minutes without the further addition of more lye. (This operation has been fully described in detail in the chapter on White Settled Soap.) More lye is then care¬ fully added in small portions, while boiling, until the soap sepa¬ rates from it. The supply of lye is then cut off and boiling is continued until by evaporation of water a very soft and large grain is formed, from which the lye will settle thoroughly and rapidly. If on continued boiling the soap remains separated from the l}’e (indicating that it has all the strength it can absorb), it is allowed rest to settle. The waste lye contains sufficient strength to require saving it for some other boil, and it is therefore no disadvantage if—ow¬ ing to the cocoanut oil—it should contain a little soap in solution, for in that case it will settle the lye most thoroughly; if the soap were grained out too strongly this would prevent the complete removal of the lye, which is very essential, and so much water would be required in the next operation that there would be dan¬ ger of the soap becoming too thin to hold the coloring matter suspended for mottling; the soap obtained would also be less neutral, and would shrink more on drying. If there should be any indication, therefore, that the waste lye has not settled so per¬ fectly that it can be drawn off entirely, a little cocoanut oil may be added afterwards and boiled through, to absorb the excess of strength. The lye is then run off, as is also any nigre that may have formed, and the open steam turned on. When the contents of m the kettle are again boiling, enough hot water is carefully run in to thicken the soap which is at first thin and stringy, and to form it into a tough, clear mass through which the steam es¬ capes with difficulty. (Instead of simple water a weak solution of silicate of soda (8° B.) may be employed. Up to 50 per cent silicate solution is sometimes used for such soaps in England.) It will be observed that the soap is now in a condition prac¬ tically identical with that of a finished “Eschweger” described, and the quality of lye used, the various signs indicating the pro- 234 Eschweger Soap. per conditions, and the remedies employed in certain irregularities are also the same. When the color has then been well incorporated the soap is framed and covered up to form the marble. CHAPTER X. > Soft (Potash) Soap. General Remarks. When, instead of the soda, potash only is employed for saponi¬ fying - the fats, the resulting - soap is very much softer than are the hard soda soaps; especially if the stock at the same time consists of the softer oils, in place of the more solid fats rich in stearin, the product will be a soap of about the consistency of lard—a true “soft soap.” (There have lately been patented in several countries special methods of making hard potash soaps which contain only about 10% of water, but these do not come under our consideration at present). In this country soft soap is but little used outside of the tex¬ tile industries, but in most other countries it has an enormous sale also for household purposes, such as cleaning floors and woodwork and for rubbing on clothes in the laundry. Its un¬ equaled solubility and handy form have made it a favorite soap many places, especially so since the evil smelling fish oil, and also the somewhat less obnoxious linseed oil, which were former¬ ly used largely for soft soap, have been supplanted by cotton seed and other oils which furnish a soap of less unpleasant odor. A soap made of oil and potash lye alone is not only the ^oap! 1 ^ 01 ° U most readily soluble of all, but also the only kind which is per¬ fectly soluble in cold water. Owing to this great solubility, its soft consistency, and to the excess of alkaline strength, caus¬ tic and carbonated, which it ordinarily contains, it saves much time and labor. Its peculiar value for the treatment of fabrics, and especially woolen goods, has already been pointed out un¬ der the heading of “ Textile Soaps ” (page 176), while it is also 236 Soft Soap. Requirements soft soap. well adapted for some toilet purposes, if properly made. As a basis for medicated soaps likewise the soft variety is frequently preferred to hard soap. The manufacture of a soft soap that answers all the demands of the consumers is in most cases a somewhat complicated mat¬ ter, for the requirements are numerous and varied, and not always easily made to correspond with that ever present enemy of soap makers—cheapness. Besides the special requirements depend¬ ing - on the class of work to which the soap is to be applied, there of are a few general properties which are more or less looked for in every soft soap, as follows: Its consistency and composition must be such that it does not become too liquid in hot weather, so as to run, nor become brittle or freeze in winter; in fact, its composition must be adapted to the season; it must have a good body at all times and yet feel unctuous; it must be “short,” so as not to draw threads on removing a portion, but on the other hand it must not be wet and slippery; it should possess a cer¬ tain degree of transparency and a good color, and—if a figged soap—the grains of potassium stearate must be formed in size to conform to the prevailing taste of the customers. That the production of a soap of these characteristics is an operation re¬ quiring considerable attention is evident from the fact that even so apparently trivial a matter as repeatedly taking small quan¬ tities of the soap out of a barrel with wet hands is sometimes sufficient to render the remaining soap stringy. The conditions which operate to form a soap answering the above description rest, briefly stated, on the selection of fats of suitable consistency to adapt the soap to the season; on the use of lye containing a proportion of carbonate or other potash salts which, as they do not combine with fat, serve to insure the re¬ quired shortness; and on the right amount of alkali and water in the soap. In this connection it may be mentioned that soft soaps contain, as a rule, more water than the good qualities of hard sonps, and that a larger quantity of potash is required to form a neutral soap with a given amount of oil than would suffice if the alkali used were soda, to say nothing of the excess of alkali which is present in all ordinary soft soaps. A perfectly neutral compound of oil and pure caustic potash forms a turbid, gummy, sticky mass, which becomes a salable soap only by the further addition of a solution of caustic and carbonated potash. While for a hard soap are required about Soft Soap. 237 100 to 120 lbs. 20 u soda lye for every 100 lbs. of stock, there are required for a soft soap 155 to 170 lbs. of (partly carbonated) 23 *—24 potash lye. Considering* furthermore that soft soaps are made by simply boiling* the fats and oils with the lye, without any separation of waste lye and glycerin, it will be seen that the yield of soft soap from a given amount of fat is considerably above that obtained in hard soaps. We shall refer again to the question of yield further on. It is seen from this that the ordi¬ nary soft soap differs from hard soaps not only in the nature of the alkali with which it is made, but also in its larger propor¬ tion of water and free caustic and carbonated alkali. In fact, soft soap is frequently described as being a neutral soap dis¬ solved in an aqueous solution of caustic and carbonated potash. As to the stock used, this may be train oil, linseed oil, cot- stock for soft ton seed oil, red oil, olive oil, rosin, with or without the addition of tallow or other fats rich in stearin. In winter thin oils are preferred, but in summer the addition of cotton seed oil, tallow, or some other stock forming a more solid soap, is necessary to secure the product from becoming too soft. Train oil, and to a less degree also linseed oil, have the disadvantage of furnish¬ ing soap of unpleasant odor which even strong essential oils (mirbane, etc.) fail to disguise effectually. But linseed oil has the advantage of rendering the soap proof against low tempera¬ tures if made with pure potash lye; in summer it requires part soda lye, without the aid of which the soap would be too soft in warm weather. Rosin is also much used, especially in brown soap, and gives it a tine, bright appearance. As it makes the soap softer, less should be used in summer than in winter, ana a little more soda lye should be used to counteract its tendency to soften the product. Regarding the lye used in these soaps we refer the reader to Lye for soft soap. Chapter III, and also to the remarks on that subject under “Eschweg” soap, which apply largely to soft soap as well, es¬ pecially to “ figged ” soap. In case pure caustic potash be used for making* the lye, it will be necessary to add about 26 to 28% of the weight of caustic, more in winter than in summer, of car¬ bonate of potash or chloride of potash toward the end of the boiling, to shorten the soap; but it is preferable in practice to begin with a lye alread}^ containing most of the salts from the start, and only adding at the finish the small am¬ ount that may still be’ wanting. In summer some of the pot- 238 Soft Soap. Coloring. Filling. ash is substituted by soda, so as to give the soap a greater con¬ sistency; too much soda lye, however, or the chlorides of soda and potash, make the soap appear turbid. In hot weather from one-quarter to one-third of soda may be employed in place of an equivalent amount of potash, but allowance must, of course, be first made for the soda, with which much of the commercial pot¬ ash is contaminated. If the lye used be too caustic, the soap boils thick and heavily, remaining at the bottom of the kettle instead of rising, and samples of the soap appear tough on run¬ ning from the paddle, and are of a hard or gummy consistency when cold; in that case some carbonate of potash solution must be added, until the soap runs off the paddle very short (in win¬ ter) or draws threads not longer than l / 2 inch (in summer). On the other hand, if the lye is not caustic enough, so that too much of salts are introduced, the soap boils up very high in the kettle, boils over readily, appears watery, and lacks consistency, so that a sample placed on glass spreads very much. To remedy such a case pure caustic lye and more stock must be added. For coloring soft soaps there are used palm oil (for yellow), rosin or sugar color (for brown), and ultramarine blue or indigo (finely powdered and previously boiled for a considerable time in water and lye) to give a green color. Of course, there have also been found ways to fill soft soaps, which may be briefly referred to here: The filling mostly used is a solution of potassium chloride in water (14° B.), of which about 1 lb. is crutched into the cool soap (at 160 to 170° F.) for every 5 lbs. of stock used. To take this filling well, it is easily understood that the soap should be made with a comparatively caustic lye rather than with one containing much carbonate. If on adding this filling the soap becomes turbid, it is a sign that caus¬ tic strength is lacking. Neutral soft soaps can absorb, dissolve as it were, certain quantities of various salts and water, and }~et remain perfectly clear. That this property is due to the salts in the filling is shown by the fact that if say 15 lbs. of simple water were added to 100 lbs. of a well-made soft soap, the pre¬ viously clear and solid soap would turn soft, turbid, and long, as soon as it is cooled, while the crutching in of a like amount of a suitable salt solution will leave the soap clear and of good consistency. It is to be observed here that in warm weather the soap remains clearer with thin solutions than in the cold; the lower the temperature of the atmosphere the stronger must be this Soft Soap. 239 kind of filling - . All potash salts can be used for this purpose with about the same effect, but potassium chloride is usually pre¬ ferred to the carbonate or sulphate for its cheapness, ready solu¬ bility and convenient use. It can be added during the boiling or afterwards, and shortens the soap more than does pearlash. Some soapmakers prefer the sulphate of soda, as it softens the soap less; this is the result of some soda soap forming in the kettle when sulphate of soda is used, and this soda soap gives greater consistency to the product; but the same result could be obtained more cheaply by using some soda lye in the boiling in the first place and then filling with potassium chloride as just described. Another favorite material is potato flour, rice flour, or starch, because the same bind considerable water and lye and thereby make the soap more solid, which may be even of advantage in hot weather; but at the same time the soap will be less clear and transparent when filled with flour. In combination with silicate of soda, starch is used in a manner as follows: Equal weights of starch, silicate of soda, and water are well stirred together; enough of the soap is then crutched in to make a creamy mixture, of which the desired quantity is crutched into the soap in the kettle. After adding this filling the soap has lost its “short” character, and requires the careful addition of some strong caustic lye (30° B.). Silicate of potash, diluted with water, is another suitable filling material for soft soap of which (at 18° B.) 25 lbs. may be used for every 100 lbs. of stock em¬ ployed; or a filling mixture containing this filler may be made of 10 lbs. silicate of potash, 15 lbs. potato flour, 20 lbs. potash solution of 12° B., 5 lbs. water and 5 lbs. potash lye of 28° B.; in using this filler, the proceeding is as follows: The potash so¬ lution, water, and flour are mixed together separately; into this is stirred some of the soap until a thin mass is obtained; the silicate and lye are mixed together and added to the soap in the kettle and well crutched through, then the flour mixture is crutched in, and lastly, when all is well mixed, some caustic lye for shortening will be required. Most fillers render the soap shorter, so that the latter should be made from the start with rather caustic lye, in order to have the right consistency after filling. Besides the materials just mentioned there are also used carbonate of soda (and of potash), and sulphate of soda. The peculiar action of soda salts on potash soap has been previously explained. (See also Appendix, Note 11.) 240 Soft Soap. Rosin. soap. Yield of On the effect of rosin, the different lyes, and the yield of soap (without filling-), a German writer made the following in¬ teresting observations: “ It may be called a rare occurrence for a soaprnaker to ob¬ tain the same percentage of yield in making several boils of one kind of soft soap. In a great majority of cases, even with the same fats and lyes, a difference amounting to several per cent will be noticed. The principal cause of this difference is the impossi¬ bility of adjusting with mathematical correctness the evaporation of water by boiling; what is ordinarily termed “ normal ” evapor¬ ation fluctuates between limits which account for these vari¬ ations. If the evaporation of water by boiling is sufficient in itself to bring about this result, it is still further explained on considering that the yield is affected also by the fats, by the greater or less causticity of the lye, and by the addition of soda in soap for summer use. “Among the unfilled soft soaps in which potash lye exclus¬ ively has been used, the “natural grain” (figged) soaps are prominent, in making which potash lye only is used in all sea¬ sons. The different fats selected for the different seasons do not influence the yield to a degree worth mentioning, as it is not so much the tallow but especially the oils which vary. Generally one-third tallow (figured on the total of fats) is sufficient, as, for instance, in summer sufficient stearin for the proper forma¬ tion of the grain is introduced by the increased proportion of cotton seed oil employed. The yield of linseed oil and of cotton seed oil may be assumed to be the same; the change in the pro¬ portions of these two oils used therefore has no practical influ¬ ence on the amount of soap produced. “The variations frequently enough encountered in the yield of these soaps generally fluctuate between 235 and 240. This is owing principally on account of stronger evaporation of water in the case of the lower figure named, for in these soaps espe¬ cially the manufacturer is careful to add potash solution if neces¬ sary to counterbalance great causticity in the lye. “ The proper degree of evaporation is recognized in such soaps by observing the froth on the surface toward the end of the boiling. When the soap, having been properly made with caustic and carbonated lye, falls in the kettle during strong boil¬ ing, this is the sign that the excess of water is removed and that boiling must be discontinued shortly after. If no formation Soft Soap. 241 of froth is then observed on the surface when th e soap has quieted down, we are justified in assuming’ that the soap was boiled down too strongly. (These remarks are based on boiling over an open fire, the excessive evaporation of water being here caused by either not drawing the fire soon enough, or by after-heating by the heat in the furnace, etc.) In this case the yield would probably fall short of 240 per cent, and in fact there is no clue as to how much water has been unnecessarily evaporated; it is then necessary for the proper yield to add so much water during slow boiling until a very little speck of froth—about the size of a 5-cent piece—is seen on the surface. This affords a certainty that the proportion of water is neither too high nor too low; still there will be small variations in the weight as frequently more or less froth is caused, which, however, does not influence the quality of the soap and therefore requires no correction if the variation is not too far from the normal condition. “Greater differences in the yield occur in the unfilled ordi¬ nary smooth and green soaps (Crown soaps), this being a natural consequence of the changes in the proportions of rosin used and in the lyes employed. The yield of soap decreases in proportion as more soda lye is used, as less soda is necessary to saponify the oil than is required of potash. Soft soaps made of pure potash lye show a larger increase, for in a case requiring 56 parts potash lye for saponification, 40 parts of soda lye of the same strength and causticity would be quite sufficient. Then the character of the lye plays an important part in the yield. Of a very caustic lye less is, of course, required to saturate the oils than of one containing more carbonated alkali, for it is the caustic lye alone which saponifies oils, while the action of the carbonated alkali is purely mechanical and by its presence naturally increases the yield. “According to season the smooth and green soft soaps con¬ tain more or less rosin. The yield is in these cases figured on the basis of the fats alone, because on account of its low price the rosin is considered as belonging rather to the filling than to the fats. “ One would think that the lye required for saponifying the rosin would add to the yield of soap in the same proportion as in pure‘oil soap, but when the rosin is boiled together with the oils from the start, it rarely causes an increase above its own weight, compared to the soap made without rosin. For example 242 Soft Soap. 1,500 lbs. linseed oil and 225 lbs. rosin (15%), without using any soda lye, furnished, according- to repeated weig-hing-s in act¬ ual practice, 3,600 lbs. soap; this is 240%, figured on the 1,500 lbs. of oil. The same result was obtained when 1,200 lbs. lin¬ seed oil, 300 lbs. cotton seed oil, and 225 lbs. rosin were used. Only once a percentag-e of 242% could be recorded. If now a pure oil soap, (without rosin and soda lye) is considered as yield¬ ing- 228%, then the 1,500 lbs. of oil would yield 3,420 lbs. of soap, and if we add to this merely the simple weight of rosin we have 3,645 lbs. or 243% ag-ainst 240% actually yielded. The explan¬ ation ©f this deficiency can only be found in the strong-er boiling- down required for soaps containing- rosin. The indications show¬ ing when enough water has been evaporated are the same in soap made with rosin as in those without rosin, but in the former they appear later, thereby causing the lower yield. “ Several boils with 10% rosin, made without soda lye, gave a yield of 236 per cent. The materials were 1,250 lbs. linseed oil, 250 lbs. cotton seed oil, 150 lbs. rosin. “The same soaps with only 5% rosin, made in the same manner, yielded from 230 to 232%. Small variations occur here also, because the lyes are never quite alike, nor is the degree of evaporation. “ The yield of summer soaps, as already said, depends on the use of soda lye. In this respect the use of the cheaper cotton seed oil is of advantage, for with the addition of but little soda a sufficiently solid soap results, together with a larger yield. In the very hot season cotton seed oil may be used almost entirely for smooth soft soaps, when of course the soda lye must be entire¬ ly omitted. In less warm weather half linseed oil and half cotton seed oil with 5 to 10% rosin, may be used, but it may then be well to use from 8 to 10% of soda lye to guard the soap against becoming too thin. The loss in the yield with so little soda lye will not be more than two or three per cent. “ In calculating the yield in the case of filled soaps it is only necessary to subtract the weight of filling used and divide the weight of actual soap by the weight of the oils used, to get the percentage of yield. For instance, if 1,250 lbs. linseed oil, 250 lbs. cotton seed oil, and 150 lbs. rosin, with the aid of 380 lbs. chloride of potash solution, make 3,920 lbs. of soap; then there are 3,540 lbs. of real soap, and this divided by 15 (1,500 lbs. of oils) =236%.” Soft Soap. 243 Thk Boiling. The boiling- is carried out either in a steam-jacketed kettle or by the aid of closed and open steam pipes. Towards the finish a considerable degree of heat is required, for which reason the use of closed steam alone would require considerable pressure in the boiler. At all events, the kettle must be placed as near as possible to the boiler, so as to avoid the cooling of the steam while it is conducted from the boiler to the kettle. In other countries an open fire is used almost exclusively, but this is very liable to burn the soap. The manufacturing process of soft soaps is almost as varied as in the case of hard soaps. If rosin is used, it may be melted with the oil and both saponified together, or the rosin is added with the necessary lye of 30° B., after saponifying the oil, and the whole boiled together. The proportion of rosin in any soft soap should not exceed 1 lb. to 10 lbs. of stock. The lye may con¬ tain the necessary carbonate from the start, or it may be caustic and the soap shortened afterward with pearl ash and chloride of potash solution, as said before. Other points of variation will appear from the following de¬ scription of the processes adopted for different soaps. CROWN SOAPS. “Crown soap” is one of the many names by which those soft soaps are known which are homogenous throughout, as distinguished from the “ figged ” soaps, which have numerous small crystals of stearin soap distributed throughout the mass. The lye is made either by dissolving commercial caustic pot¬ ash in water or by causticizing the carbonate. The first-named method is the easiest and safest, as it makes a more uniform lye. The causticizing of carbonate of potash is done as follows: The potash is dissolved in water, by means of heat, until it shows 20° B. For every 2 lbs. potash there is then added about 1 lb. of freshly-slacked lime and the whole boiled for an hour, when the lime is allowed to settle until the lye can be drawn off clear. The precipitate is heated again, with more water, to make lye of about 12° B. A third washing (anything less than 10° B.) is reserved to be used instead of water for dissolving the next batch of alkali. As the potash and the lime are of ever-varying degree of purity, this process of making the lye is liable to prove trouble¬ some in the boiling of the soap, especially to the inexperienced Boiling by steam. Causticizing pot ash. 244 Soft Soap. Stock. soap-maker. For making- a purer lye, the potash may be dis¬ solved at first to form a 40° B. solution, from which the impurities are settled out, the foreign salts crystallizing- out and settling to to the bottom or attaching- themselves to the sides of the vessel. The purified solution is then diluted to 20 B. and causticized as above. As to quantity, there are required about 36 lbs. of pearl ash (causticized with lime), or in other words, about 160 lbs. 24 B. lye for 100 lbs. of stock. Of low-grade potash, or when the soap is to be filled, somewhat more is required. The stock for these soaps may be linseed oil, cotton seed oil, red oil, and grease, in porportions to suit the manufacturer, and the season, and of course also rosin, if desired. With much lin¬ seed oil about 1 part soda lye may be used with every 2 parts potash lye in summer; the more grease is used, the less soda lye is admissible. In winter the soda lye is omitted altogether. The stock may be run into the kettle the evening previous to boiling the soap, together with say 40 lbs. of lye for every 100 lbs. of stock, and well mixed. Not much more lye, however, must be taken for this purpose, as otherwise the soap may- set in the ket¬ tle. Nor must the materials be mixed too warm or the spon¬ taneous development of heat might cause boiling over. If the lye had been made by dissolving a pure grade of caustic potash, and it is intended not to add the required carbonate until the finish, and to boil with open steam, the lye may be used from the start at a strength of 20-24 B., but if the lye had been made by caus- ticizing the carbonate in the soap factory (and therefore contains the carbonate intended to be in the soap), and if is were intend¬ ed to boil over an open fire, the weakest lye obtained in caustic- izing (10-12 B.) must be used at first, using the stronger lye as saponification progresses. In other words, the strength of the lye is regulated in accordance with its caustic strength and with the amount of water required, so as to avoid the necessity of evapo¬ rating much water at the finish. The materials begin to com¬ bine over night, and next morning steam is turned on. When the contents of the kettle come to a boil, the remaining lye is run in gradually, under constant boiling, so as to be all in the kettle at the end of about one hour. During this time the soap must not be allowed to become weak, to prevent bunching. The soap now soon becomes clear, indicating that the stock is fairly well saponified. Small samples are the’n set on glass, to see if Soft Soap. 245 the soap has all the necessary characteristics of a well-made soft soap. The sample will probably be thin, and on touching- it with the fing-er it will draw a thread; on cooling- it will lose its transparency, and be jelly-like in consistenc} T ; on the surface of the soap in the kettle there may be a lig'ht scum. These sig-ns indicate that there is an excess of water which must be evapor¬ ated in order to “shorten” the soap, by boiling- for a while long-er. If the sample is not clear, and is slippery on the glass, it shows an excess of streng-th, which can only be remedied by adding- more stock. If the sample is clear at first, but becomes gray in the center on cooling, lye is wanting. The soap which is finished correctly appears as follows : Sl ^" i s h ° f pi ’ oper While boiling, it suddenly falls in the kettle, the water having evaporated just sufficiently to shorten it enough; the soap in the kettle is clear, with very little or no froth on the surface, and the boiling mass opens in “roses” similarly as described under Eschweg soap. A heaped sample on glass does not spread very much and shows few air bubbles; touched with the finger it draws no thread, but merely forms a very small point; it is clear, and on cooling becomes surrounded by a very narrow grayish rim of lye, covered with a fine striped skin. (This latter appearance is termed “lye flower” by the German soap makers, and is the re¬ sult of the evaporation of the water from the hot sample, by which the latter appears as if evaporated too far.) In the sum¬ mer the soap should be made less strong, and the sample should therefore have this striped appearance less strongly developed than in winter, when a little extra strength protects the soap against freezing If the samples have the required appearance, the soap is fin¬ ished—unless rosin is to be added, in which case it is broken fine, thrown into the soap, and boiled, together with the necessary quantity of 30° soda lye, until the appearance of a sample, as be¬ fore, indicates that it is finished. The soap is allowed to cool in the kettle to 150 F. and then run into barrels, and crutched until cold.. FIGGED SOAPS. By appropriate manipulation soft soap can be made so that in course of storing it for a time it develops numerous crystals of stearate of potash throughout the mass, ranging in size from that of a pin-head to that of a grain of rice, giving it a “figged” 246 Soet Soap. Stock. appearance much liked by consumers. This process of crystal¬ lizing- is analogous to the formation of the mottle in hard soaps, but requires long-er time, taking- from two to six weeks. It is broug-ht about, in the first place, by the addition to the stock of some fat rich in stearin, such as tallow, for the formation of the grain; for the clear body of the soap oil is used. The lye used is potash altog-etlier, without the addition of any soda lye, and even the potash should be as free from soda as possible, as the latter prevents the formation of the crj^stals. Furthermore the lye for fig-g-ed soap requires to be still less caustic than that for the “Crown” soaps, as the soap must possess, even when cold, the necessary mobility to permit the crystals of potassium stearate to form. The more tallow or other solid fat is used, the thicker will be the soap, and the more carbonate must consequently be in the lye. If the lye is too caustic, the soap will remain per¬ fectly liomog-eneous in storing-, instead of crystallizing-. On the other hand, if it contains too much carbonate it crystallizes very readily, but also becomes syrup-like on storing-. The lye is made as described before for other soft soaps, or the lime is slacked in weak lye that may be on hand, and the potash dissolved in the latter. About 40 to 42 lbs. of lime are required for 100 lbs. of pearl ash; a little more in summer. The stock may be: Linseed oil or cotton seed oil, 65 parts; tallow, 35 parts; or, tallow, 40 parts, linseed oil, 40 parts, and cotton seed oil, 20 parts; or any similar combination. For yellow soap some palm oil may be added. The stock should be fresh, if possible; old rancid tallow requires to be previously purified. A greater proportion of tallow than just named causes smaller, but more abundant crystals. The stock is saponified as discribed for the ordinary soft soaps, and boiling- must not be carried too far, as an excessive evaporation of water retards, if it does not entirely prevent the crystallization, besides reducing- the yield. The sig-ns for a fin¬ ished soap are similar, as already described under “Crown Soaps.” When it sinks in the kettle while boiling-, and on shutting- off steam, only a small speck of froth is seen in the center of the sur¬ face, it contains the proper proportion of water. The soap may be known to have the rig-ht alkaline streng-th when a sample, al¬ most as soon as it is set on gdass, has a slig-htly turbid surface. The cold sample must be clear, with this sligdit turbidity barely perceptible; but after a short time it should no long-er be brig-ht, 4 247 Soft Soap. but rather appear covered with a bloom such as is often seen on ripe fruit. When cooled in the kettle to 150° F., the soap is run into dry and clean barrels, which are stored in a cellar, at a temper¬ ature between 55° and 65 F., which is most favorable for crys¬ tallization. Other things being equal, this process will take less time as the proportion of tallow used is larger. For filling figged soaps silicate of potash is best adapted, as Fillin £* soda prevents in a measure the proper crystallization. The fill¬ ing may be added in the following manner: Mix silicate of pot¬ ash in warm water till the solution shows 11^° B. while warm; then add 38-40° potash solution to bring the strength up to 13^° B. warm. Into 435 lbs. of this solution crutch 300 lbs. of flour. En¬ ough of the soap is then added to form a tough mass, which must draw long threads on removing a small portion. This mass is then crutched into the soap in the kettle, when some caustic lye of 27° B. must be added to restore the proper strength and consist¬ ency. The proportions used are about as follows: 2,350 lbs. soap. 300 lbs. flour. 435 lbs. silicate solution. 535 lbs. lye, 27° B. The soap to be filled should not contain too much carbonate, as the filling will shorten it to some extent. In winter less sili¬ cate and more carbonate is preferable. The carbonate, sulphate, or chloride of potash, especially the latter, can be used here also, as already described in the be¬ ginning of this chapter. Soda salts are unsuitable for figged soaps. ARTIFICIALLY FIGGED SOAP. The crystals of potassium sterate being produced by the use of tallow or similar fats, which are comparatively cheap in this country, there is scarcely any need of causing the same appear¬ ance by artificial means, as is a very common practice in coun¬ tries where tallow is very high in price compared to other stock. But in highly filled soaps also the crystals are often represented artifically. This is done—to the detriment of the quality of the soap, of course—by breaking well-burned lime into very small pieces, and sifting those out which pass easily through a coarse -ieve, but do not go through a sieve of say sixteen meshes to an 248 Soft. Soap. inch; these small pieces of lime are crutched into the hot soap and swell up in the same by absorbing* water, making* a very close imitation of the naturally fig*g*ed soap. Chalk is some¬ times similarly used, but is less satisfactory, and artificial grains of various kinds are even an article of commerce. CHAPTER XI. General Remarks on Boiling Soaps. The chapters VII., VIII and IX. have been devoted to a description of the methods employed in this country for boiling the hard soaps used in the laundry and for g-eneral household purposes; the operations of perfuming-, pressing- and reworking of scraps will be described in separate chapters, as will also the boiling- of toilet soap for milling. «1/ kL* 'll- vlx -V- 'T' *T V 'T' «T* vv A special variety of marbled soap, which also contains a Artificial n large proportion of water, may be made by cooling a boiled soap just enough to bring it to the consistency required to keep the coloring matter suspended. When the coloring matters are then crutched in, the marble is formed in a manner similar to that observed in soap thickened by boiling down. * * * * * * * There have been invented numerous devices and methods TT ^ anous with a view to improve the ordinary boiling process, such as boil- cesses, ing the fats under strong pressure with carbonated alkali, boiling with superheated steam, etc. It is very unlikely, however, that a great change will ever be generally adopted from the present ordinary boiling process, for, as said before, it is difficult to im¬ agine anything more simple. The only direction in which real improvements are to be looked for is in the mechanical appli¬ ances used for the various requirements of the soap factory, and possibly in the employment of new raw materials. * * * * * * * The manipulations described in the preceding chapters, if simpiiiie A C6SS6.S, properly carried out, will furnish excellent products in each case. avble p r o (1 pro \\ aste Lye i 250 General Remarks on Boiling Soaps. It is true that not all soaps are boiled as carefully and with as many “changes” as here described, but the simplified processes never give as good results. Nor will it be necessar}^ to describe in detail the various short cuts by which two or more operations are sometimes condensed into one, for there is nothing- mysterious about the boiling- of soap, and whoever desires to do so can readily determine how to abbreviate the making- of any soap by carefully considering- the reasons stated why each operation is conducted just as it is. For instance, a careful perusal of the chapter on Settled Rosin Soap will sug-g-est that such a soap could be made by saponifying- the tallow and rosin in one oper¬ ation, thereby saving- one chang-e; then an excess of strong- lye could be used instead of salt (or brine) for .graining- the soap, thereby saving the strengthening change also; the soap could then be thinned for settling directly after running off the lye used to grain the soap. Or, if this is not simple enough yet, the tallow and rosin could be saponified with just enough lye to leave the soap very nearly neutral, and then the latter could be thinned directly for settling. These and other suggestions will readily occur to the prac¬ tical soap maker, who will also understand their disadvantages. For this reason they have not been treated at length in these pages. We repeat, there is no mystery about the boiling of soap, but an intelligent understanding of all the raw materials, fats, lyes, salts, and of the “reasons why” of all the different operations is required, in order to come to correct conclusions in determining the course to pursue in given cases. For this reason these pages have been devoted to explanations rather than to hard and fast, but unexplained formulas, which the uninitiated could no more follow than the average human being could steer a ship across the oce¬ an, had he ever so high priced maps to guide him. ****** * Formerly much speculation was indulged in as to the best method of “regenerating” partly spent lyes, so as to bring them into proper condition for using them over again. At present they are either worked up for glycerin, if from the first change, or their remaining strength is utilized by boiling with fats and fat¬ ty acids, to recover the strength of the carbonate as well as the caustic soda. General Remarks on Boiling Soaps. 251 The weight of soap yielded by a given amount of a certain Yield fat or rosin is a matter of practical importance; but owing to the various kinds and qualities of materials used a positive answer that will hold in all cases cannot be given to this problem. One lot ot tallow or other fats, or of rosin, will turn out differently than others; besides the proportion of water present in the fin¬ ished product is not always the same. (A moderate amount of water must be present in every hard soap, besides the fatty acid and alkali, and is therefore included in the yield. Filling of any kind is, of course, not included in speaking of the yield of actual soap). The increase consists of alkali and a moderate proportion of water—less the glycerin lost—and of course is somewhat higher in settled soap than in the boiled down soap. There is also considerable difficulty in ascertaining the exact yield in a given case, from the fact that in a large boil on a man¬ ufacturing scale it is next to impossible to accurately weigh all the fat and rosin used, the good soap obtained less the filling that has been added before framing, and the good soap still con¬ tained in the nigre. It is therefore generally considered sufficient to estimate that “100 lbs. tallow, saponified with soda lye yield about 150 lbs. of soap; rosin increases slightly less than tallow; cocoanut oil yields somewhat more.” An experiment on a small scale would permit of more accu¬ rate observation, but it is impossible to say just how near the re¬ sults are to those actually obtained in the factory. The details of such an experimental boil recently made by Mr. C. Melzer, and reported by him to the American Soap Journal , are of interest in this connection; the following is an extract of the essential parts of the same: “The quantities operated with were 10 pounds 74 per cent Solvay caustic soda, 25 pounds prime tallow, and 25 pounds K rosin. The 10 pounds caustic soda made 67 pounds lye of 20 B. at 60° Fahr. To saponify the 25 pounds tallow I required 26 pounds of the 20° lye and produced 42)4 pounds curd soap. The waste lye which was very slightly alkaline marking 12 B. at60° Fahr Without removing this waste lye I added to this soap in kettle the 25 pounds K rosin, used 23pounds of the 20 lye for saponifying the same, and grained out with a little more salt. The total soap now weighed 81 yi pounds, showing that the 25 pounds rosin had produced 39 pounds. The very dark-colored of hard 252 General Remarks on Boiling Soaps. waste lye now marked 14 B. at 60° Fahr. and contained alkaline strength which I estimated equal to 1 or 1)4 pounds of 20° lye, thus leaving* 22 or 22)4 pounds 20 lye actually required for saponifying- the 25 pounds rosin. “The appearance and general properties of this 100 per cent, rosin-soap correspond to the old-fashioned boiled-down rosin soap of anti-bellum times of which it was said that it answered equally well for washing the clothes and for rosining the bow. Next, I settled this soap in the usual way, and after a repose of four hours dipped out 49 pounds settled soap. There were pro¬ bably two or three pounds more, but this could not be dipped out without getting more or less nigre also. This settled soap is of good color and filled with 7 per cent. 33° Carb. soda solu¬ tion (i lb. 58 per cent Solvay Process Co. “Pure Alkali” (Carb. Soda) make 3 >2 lbs. solution of 33 at 120° Fahr.) looks all right, but, of course, is quite sticky. Adding salt brine to the nigre I boiled it down to a sharp grain which weighed 34)4 lbs. The waste lye weighing 15 B. at 60° Fahr. remaining clear and had very little alkaline strength. Of course this weight of settled soap and nigre is disproportionate, the settling operation on so small a scale being imperfect. In practice the nigre is much smaller, varying from one-fifth to one-third of the total. It will be noticed that the combined weight of settled soap and nigre is two pounds greater than that of the curd soap previous to settl¬ ing, which difference represents the extra water held in the settl¬ ed soap. “Why we should be able in an experiment like this to pro¬ duce a larger quantity of soap with a smaller quantity of soda than in actual practice I cannot explain, unless it is that in the experiment we know the quality and quantity of the materials and of the product, whilst in actual practice we do not. In the experiment referred to, I used at the rate of lbs. 74 per cent caustic soda to saponify 100 lbs. of stock consisting of equal parts tallow and rosin; in actual practice the proportion of rosin as compared to the fats is about 50 rosin to 100 fats, and if these figures are taken as a basis, it will be found that I used )ust about 15 lbs. 74 per cent caustic soda to the 100 lbs. of stock. According to the law of equivalents this is more than enough; and whilst I do not wish to prove my figures in this way, I shall hold that they are about correct until convinced of the contrary by other means than the results supposed to be obtained in actual practice.” General Remarks on Boiling Soaps. 253 Referring- to calculating- the yield in actual practice the same writer remarks: “The manufacture of commercial soap is not an exact sci¬ ence; we may say that the acids and bases employed in soap mak¬ ing- will only combine in fixed proportions according- to their equivalents, and any surplus of one or the other will not enter into the combination no matter what the soap maker may do. That is all g-ood enoug-h, but the practical soap maker does not aim to produce a neutral salt, that is, not g-enerally. To attempt to tell, from accounts kept in the factory, in any but an approxi¬ mate way, how much of this and that material was used, and how much soap was produced therefrom, is impossible. I keep ac¬ counts of every batch of soap made in our factory, but make no pretense to their correctness other than that they show the pro¬ bable quantity of fats and rosin consumed and the number of frames of soap produced. “I will here quote from my kettle book the debits and credits of six successive batches of soap, which will show about as cor¬ rect results as is possible to obtain in this way. “The first two of these six batches of soap were made in clean kettles (kettles Nos. 2 and 3); on the nigres remaining therefrom two more batches of the same (high grade) soap were made, then the nigre in No. 3 was pumped into the nigre in No. 2, and some stock added, and this made into a batch of second grade soap; after this the nigre in No. 2 was pumped into a nigre in kettle No. 1 remaining from a previous batch of low grade soap, stock added and worked again into a batch of low grade soap. The nigre now remaining in kettle No. 1 may be con¬ sidered an offset to the nigre previously in this kettle, and as I work up no soap trimmings in our kettles there is nothing to estimate in this direction. “The aggregate quantity of fats (tallow, white and yellow grease) used for these six batches, was 130,500 pounds, rosin 44,500 pounds; soap produced, 292 frames. Our frames are 48 x 42x15 inches and considered to hold 1,100 pounds of soap. I have never weighed one, and it is not convenient to do so, but taking the average of the quantity of soap we cut out of a frame, and add¬ ing to this the weight of the trimmings, 1,075 lbs. appears to be about right, and I take this weight as the basis: 292 frames of 1.075 lbs. = 313,900 lbs. of soap, and deducting from this 36,- 500 lbs. of carbonate soda, etc., added in the crutcher (the et 254 General Remarks on Boiling Soaps. cetera represents the perfume), we have 277,400 lbs. soap pro¬ duced from 175,000 lbs. stock consisting- of fat and rosin in the proportion of 100 fat to 34 rosin, or an increase of 58^2%. This does not show up so well as in the experiment, and in look¬ ing- for the probable cause, I find the following-, which in a measure applies to our factory only, but corresponding- causes may and probably do exist in every other factory. In the first place, our fats are pumped into the kettles from reservoirs sup¬ plied with a g-aug-e similar to those on railroad watering- tanks, each divisonon this g-aug-e representing- 1,000 lbs. of fat. Tak¬ ing- for granted that these gaug-es are correct with the fat at a certain temperature, say 110 Fahr., then the fats would always have to be measured when at this temperature or the necessary correction made if taken at a different temperature. This is not the insignificant matter it seems to be, for fats and oils are ex¬ panded more by heat than liquids in general, and based upon the figures given by Deite (Handbuch der Seifenfabrikation, page 11) the difference in the volume of 25,000 lbs. fats or oils differ¬ ing 36° Fahr. in temperature, would be equal to about 500 lbs. This correction, however, is never made. A still more important item is the impurities and water held in suspension by the fats. “Several months ago, I worked up a lot of grease stearin which contained a very considerable amount of albuminous mat¬ ter, but this could not be readily separated, except from the spent lye of the soap, and ver} T recently we bought white grease that looked wet, but precipitated no water on being melted; a moisture determination, however, showed that it contains over 19%. This grease is of peculiar nature and origin, but as it is not likely that the readers of the Journal will have any of it to deal with, I will not mention it further. With rosin it is even worse; there is opaque rosin and trashy rosin, and rosin of which we do not know whether it will increase 30 or 60%; it is even difficult to get at the exact weight. We weigh or average the barrels and deduct 40 lbs. for Alabama or 70 lbs. for Savannah cooperage, and when we come to a dark or trashy barrel, the whole, or such part as is bad, is thrown out and the estimated quantity deducted, or it is not. This may look like great carelessness to the theorist, but he would very probably do the same way if he were engaged in the manufacture of commercial soap on a reason¬ ably large scale.” The exact quantity of alkali required for saponifying a given General Remarks on Boiling Soaps. 255 amount of fat is a question which is of greater importance in making- soap by the cold or half-boiled process than in boiling-. During- the latter the soap-maker can determine when more lye is required, and can also readily see when an excess is present and remove the same from the mass; be is, therefore, content to use as much alkali as the fat can possibly absorb, as this increases his yield of soap. The quality of the stock is too variable to calculate with sufficient accuracy in advance the amount of alkali a large boil will absorb. In the cold and half-boiled process, however, the calculation is made as near as possible, since in this case there is no other way than to mix the lye with the fat in proportions estimated to be correct. * * * * * * * The temperature at which a soap is framed is of importance in most cases. Apart from the filling operations in the crutcher, as described under “settled soap,” the temperature also affects the behavior of the soap in the frames. A pure (unfilled) soap, cooling slowly in the kettle, will assume a different formation and texture than one poured hot into the frames (where it cools more rapidly than it would in the kettle), because in the two cases the crystallization of the stearin soap from the olein soap will proceed differently. This difference is noticed even between large and small frames. A soap which in a 3,000lbs. frame, for instance, shows a small crystalline formation and dries in straight lines after cutting, will have a large grain if run into a 6,000 Ids. frame, and will perhaps dry crooked after being cut into bars. This is a subject which must be studied in regard to each special soap made. ******* From careful observation it appears that, just as soap is de¬ composed in the act of washing in ordinary water, so a certain amount of decomposition takes place each time a soap is “salted out;” at the same time the amount of free alkali present is re¬ duced. Thus a soap which, after salting out for the first time contained 0.30% free alkali and 0.56% free fatty acids, after a second salting out showed 0.19% free alkali and 2.25% free fatty acids, and another repetition of the process increased the free fatty acids to nearly 4%. Framing. Decomposition by graining. * * " |; m H ■Hi . ? . CHAPTER XII. Half=Boiled Soaps.* Gknerai. Remarks. The manufacture of soap by half-boiling- consists, briefly, Methods of hair in mixing the melted stock with lye, either (preferably) in the bomng ‘ crutcher or in the soap frame. The lye is used quite strong (say 35° B.) and the temperature of the stock may be taken at about 140° F. from the start, so that it will rise to 180-200° when the reaction of the lye on the stock causes the spontane¬ ous generation of additional heat. Others use the fat just warm enough at first to melt it, mix it with the lye, and when the ingredients begin to combine turn on steam in the jacket of the crutcher to raise the temperature to say 180 c F. or over (according to the stock, etc.), keeping it at about that point till the soap is of uniform consistency. This latter process has the disadvantage that it may easily cause the soap to boil over un¬ less carefully watched, and that a jacket crutcher or a water bath must be used, while the proceeding first mentioned permits of the use of an ordinary crutcher and, as already stated, may *The term “lialf-boiled” soap is not applied by all soap makers to signify the same thing. Mostly it is employed to designate those soaps which are made without actually boiling the ingredients, but are formed at a higher temperature than that used for the “cold-made ” soaps to be described in the next chapter. We shall employ the term in this sense in this treatise. (Others include in the denomination “half-boiled ” all hard soa p_other than cold—made without change of lye, and which therefore contain all the glycerin and impurities of the stock. This definition would therefore include the “ Escliweg ” soap already described in Chap¬ ter IX.) 258 « Half-Boiled Soaps. Advantages and disadvantages of half boiling. Purity of stock. Lye. Prepared silicate. • • even be carried out in the soap frame. In case stock containing' much free fatty acid is employed, the reaction is so rapid that much heat is quickly evolved, so that in such case the stock should be used at a somewhat lower temperature; it is preferable, however, to remove the free fatty acids beforehand by preparing the stock as for cold-made soap. It will be readily understood that the action of the lye on the stock is necessarily less complete in this case than in the process of making- soap by boiling-, and that the product will naturally contain some uncombined ingredients, besides all the impurities that may have been present in the stock and lye, and the glycerin formed by the chemical action. But, on the other hand, this process permits of remedying defects which may ap¬ pear in the course of manufacture, which is not the case in the cold process, to which it is therefore superior. The soap will also be somewhat imperfect on account of the impossibility of calculating exactly the amount of lye to be used for a given am¬ ount of stock; however, the half-boiling process is in this res¬ pect preferable to the cold process, since it is possible to make necessary corrections when making soap by half-boiling, if to¬ wards the finish there is either a lack or an excess of strength apparent. The purification of the stock being of special importance, the treatment with lye as described for bleaching tallow (page 43) is applicable for all kinds of stock for this purpose; or any of the other bleaching processes mentioned in the description of various fats and oils might be used, if preferred. The lye treat¬ ment is indicated, also, for the removal of free fatty acids from the stock, as the presence of these interferes with the proper saponification in all cases where actual boiling is not employed. In the process of bleaching those impurities are removed whose presence is especially objectionable as tending to impair the keeping property of the soap. The lye used for half-boiled soap should be as caustic as possible; in other words, should be made from the highest grade of caustic, as the presence of foreign salts in the lye is an ob¬ stacle to the proper combination of fat and lye. (Compare also the remarks on this subject under “Cold-Made Soaps.”) If silicate is used in the soap, care must be taken that the same has sufficient alkaline strength. Ordinarily to every 100 lbs. silicate 25-30 lbs. of 35° lye must be added, in order to pre- Half-Boii.ed Soaps. 259 vent the silicate from crystallizing - in the soap, from lack of strength. To properly prepare the silicate for this purpose the lye is added until its presence is perceptible to the taste, then just enough silicate is added till the taste of the lye disappears ag’ain; prepared in this manner the silicate will not spoil the appearance of the finished soap by crystallizing - or coming - to the surface; nor is it so likely to cause soft and spongy parts in the middle of the frame, as unprepared silicate is very apt to do. If preferred the silicate may be mixed at the start with the lye required for a batch of soap, and sufficient of that lye be used for both fat and silicate. # The soap being g-enerallyof a very dense consistency, owing to the low temperature employed, the crutcher should be ar¬ ranged to run slowly when used for the half-boiling process, and stirring should be continued only as long as necessary; to attain this object it is desirable to have the crutcher connected with a separate engine, whose speed can at all times be adapted to the requirements of the crutcher Or, where this is not pos¬ sible, the cog-wheels on the crutcher (or the pulleys on the counter shaft) must be arranged so as to give a slow speed to the machine. When half-boiled soap is crutched fast or too long it is apt to become spongy and floating by the incorpora¬ tion of air bubbles. For the same reason those crutchers which have a screw and center tube (see Fig. 33-41) should be filled sufficiently to have the latter covered at least with two or three inches of soap, so that in falling over the edge of the center tube the contents cannot catch air. The size of the frames should correspond with the capacity of the crutching machine, when the latter is filled as indicated; or if the frames are not large enough the center tube of the crutcher will have to be cut down sufficiently. The crutcher should always be heated somewhat before running in any of the stock, as this not only guards against undue cooling off, but also prevents the soap from sticking to the sides and causing lumps in the mass. It is also a convenient arrangement to connect the steam pipe which leads to the jacket with a cold water pipe, to be used in case the oil should be too hot at any time. This cold water connection is also very useful because, by applying cold water in the jacket in time, as soon as signs of rising are noticed, boiling over may be prevented which is other¬ wise very liable to occur at times. (See Fig. 23). Crutching. 260 Half-Boiled Soaps. Amount o used. Pearl a s tion. Strength o i iye Particular attention must be paid to using - the correct am¬ ount of lye required to saponify the stock for a batch of half- boiled soap. An excess of lye will make the soap too sharp; if not enough lye is used part of the fat remains unsaponified, the soap will be smeary and soft and, if the miscalculation is con¬ siderable, the soap in the crutcher will be so thick that it is al¬ most impossible to get it out for framing. As to the proper amount to be used, variations occur, owing to the differences in the stock, to the grade of caustic, and to the purpose for which the soap is to be used, washing soaps made by half-boiling or by the cold process being frequently made intentionally so as to have a very slight excess of strength. (See also the remarks on this subject in the chapter on cold-made soaps.) In calculating the amount of lye necessary, the figures named in the chapter on the cold process may be used as a basis; but it must be remembered that a more perfect combination re¬ sults from half-boiling, for which reason from 2 to 3 per cent more lye may be used in it than for the cold process. Of a very pure lye, and for average stock, about 335 lbs. of 35^ B. soda lye may be calculated for 600 lbs. of tallow and similar fat; only for cocoa- nut oil about 355 lbs. are required. As said before, if this am¬ ount is found to leave the soap either too week or too sharp, it is an easy matter to make the necessary correction in the crutcher before framing. 1 soiu- Strong pearl ash solution is sometimes added to the mass in the crutcher from the start, as it renders the soap more liquid and better to work; it also improves the texture of the product by giving it a finer grain, but as it does not combine with fats the finished soap will contain free carbonated alkali. To avoid this in a soap intended for toilet purposes, it is more to be recommended that some of the caustic soda lye be substituted by caustic potash lye, instead of using the pearl ash solution. ive. Regarding the proper strength of the lye for half-boiled soap, 35° is in most cases best adapted. Tallow, cotton seed oil and olive oil, however, if worked with only a small addition of cocoanut oil, make a smoother soap when the lye is reduced to 30-33 B. As it is a great convenience in some cases to know about how much water is required to reduce a certain amount of lye of a given strength to one of the weaker degree, we give the following example of such a calculation, which will answer in cases where the lye is to be diluted only by a few degrees : Haef-Boieed Soaps. 261 Supposing- our lye is 39°, and we want to use 350 lbs. lye at 35°; how much lye and how much water must we take ? Ans¬ wer : 350x 35-12,250 lbs.°; divided by the degrees of our lye: 39 -j- 12,250 = 314. There are therefore required 314 lbs. of 39° lye and the balance (36 lbs.) of water. This calculation is not absolutely correct, but sufficiently so for most purposes when the lye is to be diluted only by a few degrees. If the soap made is to be white, a trace of ultramarine blue is frequently added, whereby the naturally yellow tint is changed into a less noticeable greenish color. The addition of some pot¬ ash or sal soda solution will also make the soap appear whiter, but at the same time make it more brittle and alkaline. If starch, silex or any similar fillers are to be used, they are mixed with the oil before running it into the crutcher and the mixture strained into the latter to avoid lumps. If, in cases of extremely high filling, the oil cannot hold all this extra material without thickening too much, some of it must be added to the lye (ex¬ cept the starch, which would form a stiff paste and not work well). If many batches of soap are to be made, requiring many suc¬ cessive weighings of fats and lye, it is best to have two scales, with a sheet iron pan each, provided with a faucet near the bot¬ tom to empty it. The fat is run into one of the pans, weighed, and the faucet opened to let the stock run into the crutcher ; the lye is then similarly weighed, etc., on the other scale. When only one scale and one pan are used the weight of the latter is increased with every weighing, owing to the remnants of fat and lye, which will partly saponify and remain behind on emptying the pan, thus giving rise to errors in weighing. The particles of soap are also liable to stop up the faucet. The process of making soap by half-boiling resembling the cold process in many particulars, some further useful hints may be found in the chapter describing the latter, to which the reader is referred. Diluting lye. White soap. Filling. Weighing the stock. Similarity to the cold process. HALF-BOILED WHITE SOAP. To make a white soap by half-boiling, proceed as follows, observing at the same time the preceding “General Remarks”: The fat may consist of any suitable combination, such as, tallow 4 parts, cocoanut oil 1 part, cotton seed oil 1 to 3 parts, clarified in the manner referred to before. The amount of lye is 262 Half-Boiled Soaps. Using weak lye for correction. Crutcliing after framing. calculated with reference to the nature of the stock used, in ac¬ cordance with the figures just given. If silicate is to be added also, it must be prepared with lye, as already stated. The fats are used at a temperature of 140° F., and the lye at the ordinary temperature of the atmosphere in summer; in cold weather the lye should be brought to a luke warm temperature. The silicate is first crutched in, and then the lye. (Or, if preferred, the sili¬ cate may be previously mixed with lye, as already explained.) The mixture is now allowed to stand for 1 to 1)4 hours, until it is ob¬ served to become heated by the action of the lye on the fat. Then the crutching machine is started slowly , and if the soap shows (by its taste) a deficient alkaline strength, a few pounds of lye, diluted to 10° B., are added, so that the desired strength is at¬ tained. Strong lye should not be used for this purpose, as it would cause the formation of lumps. If, on the other hand, the soap is observed to be too strong, a little cocoanut oil must be added. These additions, however, must never be made until the mass has been standing in the crutcher at least 10 to 15 minutes after the the machine was started up. Different stock does not combine with the same rapidity, which must also be taken into consideration. When the materials have combined into a homogeneous mass, the soap is run into the frame and stirred by hand for 15 to 20 minutes, in order to avoid the formation of streaks. This is a rule which applies to all smooth soaps made by half-boiling. A somewhat different soap results from the following slightly changed proceeding and different stock : Tallow.440 lbs. Cocoanut Oil. 60 lbs. Soda Lye, 34° B.220 lbs. Potash Lye, 30" B. 60 lbs. The fat is heated to 125 F. and the lye worked in; the crutcher is covered, and in 1 to 1)4 hours the mass will become heated by the chemical union of the ingredients. If necessary to do so, steam is then very carefully turned on to bring the heat to about 180 F. and retain it at that point for some time, until the soap is uniformly clear and well formed, when it is run into the frames. HALF-BOILED SOAP FOR MILLING. Although the soap for milling purposes is made in most cases by boiling, the half-boiling—and even the cold process— Half-Boiled Soaps. 263 are occasionally employed, although they are less to be recom¬ mended for this class of soaps than for any other. A soap of this kind may be made of about eight parts of tallow and two parts cocoanut oil, treated in the same manner as just described for a white soap. Another suitable combination is : 350 lbs. tallow, 200 “ cocoanut oil, 50 “ castor oil, 300 “ lye, 38° B., diluted with 26 “ water. As milled soap, more than any other, is expected by the con¬ sumer to be well made and to retain its fine appearance and odor for a long time, it is necessary to observe every possible precau¬ tion to secure the most thorough saponication possible. If an appreciable proportion of unsaponified fat remains, the soap will soon turn rancid, acquire a dirty color and a rank odor. On the other hand, a milled soap is expected to be also free from uncom¬ bined alkali, and an excess of strength is, therefore, to be avoid¬ ed with the same degree of care. While it is not possible to manufacture a faultless piece of soap, except by careful boiling, a salable and for many consumers quite useful milled soap may be prepared by half-boiling. As a means to promote the combination, a solution of sugar in water is sometimes added to the soap, which thins it out some¬ what and helps to bring it into a condition favorable to more complete combination. The process of milling itself will be described in a separate chapter. HALF=BOILED flOTTLED SOAP. The manufacture of a mottled soap in the crutcher is not entirely satisfactory. However, as it may be profitable in some cases, we give herewith the points to be observed. The soap must be made neutral, and resembles in most particulars the Eschweg soap described in chapter IX., but, owing to the lower temperature, the tests there given for the proper finish are of no use in a half-boiled soap. The materials used may be as fallows: 500 lbs. tallow, » 100 “ cocoanut oil, 100 “ cotton seed oil, 410 “ lye, 34 or 34^° B. 264 Half-Boiled Soaps. The stock to be of a temperature of 150° F. It is necessary to leave the soap, when it seems to be finished, in the crutcher for at least 15 to 20 minutes longer, as it might happen that the soap is deficient in lye; it would then become weak in the frame, although it may have appeared just right in the crutcher, unless lye is added as soon as it is observed that, on standing in the crutcher, all the strength has disappeared. After saponification a solution is added consisting of 8-10 lbs. salt and 6-8 lbs. potash in 50 lbs. of water, the desired color hav¬ ing been mixed in the brine. The frames must be well covered until the mottle forms. Silicate—prepared with lye—and other fillers may be used. (Compare also “Eschweger III.” page 229). HALF-BOILED FLOATING SOAP. This may be made of tallow (or grease) and a small propor¬ tion of cocoanut oil. The batch is made of such a size only that the center tube in the crutcher is above the surface of the soap so as to cause the soap falling over the rim to catch air in crutch- ing. The stock should be at about 120 F., and no steam is ad¬ mitted into the jacket after saponification has set in. After crutching briskly until a sample taken out is quite light, and swims on water when cold, the soap is framed and allowed to cool as quickly as possible, that it may retain the air bubbles evenly throughout the frame. If the soap is made too warm, it will settle in the frame and will not float after pressing. (Min¬ eral soap stock and some silicate might be used for filling, but are not to be recommended in this class of soaps). Soap made by half boiling, of stock containing x /z or more of cocoanut oil, is difficult to make so that it will not float, as its consistency is such that it will retain any air that may be crutched into the mass. In this soap particularly the lye should be as caustic as pos¬ sible, and care must be taken not to make the soap too thin. ROSIN SOAP BY HALF-BOILING. When a rosin soap is to be made by the half-boiling process the rosin is melted together with an equal amount of tallow, strained, and weighed in with the other stock. The temperature of the stock and lye must not be above 130° F., for rosin saponi¬ fies more quickly and causes greater heating in combining with the lye than does oil. With a higher temperature than 130° F. Half-Boiled Soaps. 265 on the start the soap is liable to become so hot that it would rise out of the crutcher, and the part not spilled would be spongy and floating. The soap thickens rapidly and must be framed with¬ out waste of time; in the frame it becomes heated spontaneously a second time and the previously rather doubtful looking mixture becomes a good soap. A friend in Marseilles kindly furnishes the following ex¬ ample of how this soap is made in France: Cocoanut oil,.2,000 lbs. Palm oil (Lagos, red). 200 “ Rosin. 600 “ About one-third of the required lye, made of 70-72° soda, is heated to 90 C. (194° F.) and then the entire stock is thrown in and the heat slightly increased. Now the remainder of the necessary lye is introduced in small portions till the soap indi¬ cates by becoming clear that it is well formed. The soap is fill¬ ed (shortened) by a solution of half soda ash and half pearl ash, and finished by boiling lightly for about half an hour, when it is covered until next day. The whole operation takes 5 or 6 hours. A rosin soap made by the half-boiling process will take all kinds of filling, the same and even better than a settled rosin soap, if made with lye of from 30-35 B., and will give from 157 to 165 lbs. soap from 100 lbs. stock, without the filling. The addition of a little palm oil will improve the color. (See also formulas in chapter on the cold process). TAR SOAP BY HALF-BOILING. Weigh the stock into the crutcher, and use not over one- tenth to one-sixth tar, because a greater quantity would make the soap soft and color the lather. According as the stock is more or less hard, use the lye at 36 or 37 B. The stock may consist of say 250 lbs. cocoanut oil, 250 lbs. tallow, 50 to 100 lbs. tar, and 275 lbs. lye at 36° B. The materials will join in ^ to 1 hour. The temperature at first should be as low as possible, and care must be taken not to use tar admixed with water, as isolten the case. After the materials have joined they should be left in the crutcher for 15 to 25 minutes, as the stock saponifies un¬ equally and the soap might prove sharp to the taste for some time; if stock were then added to take out this strength the soap might prove weak and too soft in the frame. If pre- 266 Half-Boiled Soaps. ferred, the soap may be made in the ordinary way and the tar crutched in when the soap has been well formed. FILLED HALF-BOILED SOAP. (Specially suitable for Laundry Chips.) 315 lbs. tallow. 55 lbs. cocoanut oil. 40 lbs. mineral soap stock. 185 lbs. silicate of soda. 30 lbs. 32° B. potash solution. 280 lbs. 35° lye. Warm the stock to 140 B. and add the lye as in the other soaps described. When the soap is in the frame, crutch it till it is quite thick. HALF-BOILED COCOANUT OIL SOAP. A pure cocoanut oil soap may be made by half boiling- in the manner described in the preceding- pag-es. As has been stated already on various occasions, this oil lends itself more than any other for filling- with various salt solutions, without causing- the soap to become soft, especially if an excess of lye be also used. Such soaps are of course not to be recommended, as they are wasteful in use and injurious to the skin; but since there is a market for soaps of this kind, at prices at which better products cannot be furnished, the manufacturer is often practically com¬ pelled to make them. We append the following- receipt as an example: Cocoanut oil. 300 lbs. Soda lye 34° B. 225 lbs. Potash. 60 lbs. Salt. 40 lbs. Soda ash. 20 lbs. Water. 385 lbs. The water is heated and a portion of it used to dissolve the potash and soda ash; the remainder is used to moisten the salt. About two-thirds of the lye are crutched into the oil, and when the ingredients combine some of the hot water is added. When the mass is uniform, the soda and potash solutions are added al¬ ternately, in small portions. The salt is next added, and then the remaining one-third of the lye. The temperature of the soap must, during the whole operation, be maintained at 190 to Half-Boiled Soaps. 267 195° F. When all is incorporated, the soap is covered up for two hours. At the end of this time, if there is any froth on the sur¬ face, a little more water is required. If small samples taken out are too hard or too sharp, a little oil mixed with some hot water is crutched in. The amount of filling- which such soaps will absorb, in the form of various salt solutions, is almost unlimited, but they natu¬ rally dry out considerably on aging-. The above process is highly recommended by some soap- makers of the old school, but it should be added that the soap will turn out fully as well made if a go > 1, pure soap is made first, and the filling added only when the soap proper has been finished. TRANSPARENT SOAPS. V These are made very largely by half-boiling, but will be de¬ scribed in a separate chapter. » CHAPTER XIII. Cold=Made Soap. ADVANTAGES AND DISADVANTAGES OF THE COLD PROCESS. As was explained in Chapter VI., the “Cold Process” of making’ soap consists in intimately mixing with each other cer¬ tain proportions of the fats or oils and strong lye, at about the melting temperature of the stock, and then running the mixture into the frames to work out its transformation into soap by it¬ self, with the aid of the heat generated spontaneously by the ac¬ tion of the ingredients on each other. As the chemical action progresses, the mass rises in temperature, until at last the fat and lye have combined, when chemical action gradually becomes less energetic and at last ceases altogether; the heat disappears slowly, and at the same time the soap formed hardens in conse¬ quence of the lowering of the temperature. It is seen that no separation of waste lye takes place in this process, and cold-made soap, therefore, contains—like half-boiled soap—all the impuri¬ ties that may have been introduced with the stock, all the water used for making the lye, the foreign salts that may have been contained in the caustic, the glycerin formed during the forma¬ tion of the soap, and also more or less of the raw materials in an uncombined state. The cold process is applied chiefly to the manufacture of laundry soap and of the cheapest grades of toilet soap, and sometimes also to soft soap. As it resembles in many particulars the half-boiling process described in the preceding chapter the reader, is referred to the same for additional details. As may be readily supposed, a method of manufacturing soap, so different from the boiling process, has certain advant- 270 Cold-Made Soap. ages as well as disadvantages of its own, and according to vari¬ ous conditions and circumstances a factory may find it advanta¬ geous to make all "its soaps by boiling, or all without uoiling, or it may use both processes for different products. Many of the smaller factories which work by the cold process exclusively, undoubtedly did so in the first place because a com¬ paratively small outlay was sufficient to buy the necessary plant for making soap without boiling; and once having established their special brands, these factories generally find it neither con¬ venient nor advisable to change their products by adopting new manufacturing methods. A mixing vessel with suitable stirring apparatus, a lye tank, a few soap frames, a furnace for melting the stock, a press to finish the cakes, and a few smaller imple¬ ments,these constitute the machinery required with which alone, if necessary, a soap factory on the cold process can be, and fre¬ quently has been started. Another reason why the cold process exclusively is employed by some factories, is the fact that small quantities of soap can be very conveniently made by it. The boiling of soap requires ap¬ paratus, labor and time, which are too expensive to apply except for a fairly large batch, to say nothing of the practical impossi¬ bility of properly finishing a small batch of soap by boiling. In connection with this there is the further advantage that by the cold process a batch of soap can be turned out on very short no¬ tice, and certainly much more rapidly than by boiling. Again, while experience and good judgment are certainly required to make a good soap by the cold process, it is at the same time easier to acquire a certain knack of making a passable piece of soap in the cold way, than it is to learn the art of soap boiling; probably this fact has also had a tendency to make the cold pro¬ cess a favorite with many smaller factories that are being estab¬ lished from time to time in towns growing at some distance from the larger cities. But, as mentioned before, there are also numerous factories making large quantities of soap by boiling which nevertheless use the cold process for certain of their brands, showing that there are still other reasons for making cold-made soap besides those just mentioned, depending on the properties of the product itself. Among these a prominent one is the fact that cold-made soap, while fresh, has a better appearance than almost any boiled soap, which is owing partly to its amorphous texture that causes Cold-Made Soap. 271 the cakes to preserve their square outline form for a longer time, instead of warping, like cakes of boiled soap. Their color also, if carefully made, is generally more beautiful. In general appear¬ ance a fresh, cold-made soap resembles a milled soap more close¬ ly than do the boiled soaps (but owing to its amorphous texture it has not the peculiar mark on the ends of the cake which milled soaps, and to a less extent also most boiled soaps, acquire in pressing). On aging, however, cold-made soap sweats readily, dries up, and then has a much less beautiful appearance than a boiled soap of the same age will possess. The length of time during which a cold-made soap will preserve its fine appearance depends partly on the care used in manufacturing it, on the amount and kind of filling used, and on the nature of the stock, cocoanut oil soap being less changeable in this respect than that made of tallow, grease, etc. The most important disadvantage under which cold-made soap labors, is the impossibility of securing a perfect combina¬ tion of the fat and lye, so that no free fat and alkali will remain present. Apart from the impossibility of calculating the exact proportion of lye which a'given amount of fat will require in or¬ der to form a neutral soap, it is also beyond the power of the cold process to combine all the materials perfectly, even if the right proportions were used. There will consequently, under all cir¬ cumstances, remain some free fat and some free alkali in the soap, causing sharpness and sweating on one hand, and (later on) rancidity on the other. In this respect the half-boiled process gives better results, although not equabto those of boiling. A peculiarity of cold-made soap is that it washes away more rapidly than boiled soap made from the same stock; it conse¬ quently lathers more freely and may perhaps be appropriately compared in this respect to floating soaps. SELECTION OF THE STOCK. When the cold process was first employed for soap making the lyes were still universally made by causticizing carbonate of soda in the soap factory; the resulting lye was rich in carbonated soda and other salts which are incapable of combining chemi¬ cally with neutral fats, and as a consequence the lye and the stock would not combine with each other to form salable soap, unless a large proportion of cocoanut oil was used with it. It thus came to be accepted as a rule that cold-made soap could only 272 Cold-Made Soap. be made by using- at least from one-third to one-half cocoanut oil in the stock. At present, however, where hig-h grade lyes are as easily made as those of lower grade the cold process can be employed for all kinds of stock, even without any cocoanut oil at all if so desired. The selection of the fats most appropriate for a soap of certain characteristics is the same as for boiled soaps, with the difference only that, along- with the other considerations, a naturally some¬ what readier solubility of cold-made soaps must not be overlooked. For some cold-made toilet soaps cocoanut oil alone is used, and these readily produce an exceedingly abundant lather, ow¬ ing to the naturally great solubility of cocoanut oil soap; it there¬ fore washes away rapidly, and a delicate skin cannot bear its constant use, as such a soap acts too energetically, for the reason just given. Of the several varieties of cocoanut oil the Cochin oil is pre¬ ferred for the cold process, especially for making white soaps, as it is the whitest, usually the freshest, and produces a soap which has less of the peculiar odor characteristic of cocoanut oil soaps; it also gives the product a better appearance, both for white and colored soap. However, its quality varies considerably indiffer¬ ent shipments, as is also the case with Ceylon oil, which some¬ times contains so much free fatty acids that thesoap thickens up before all the lye can be stirred in. This difficulty is overcome by purifying the oil, as described further on, and also in the chapter on fats and oils. But in factories where any other use can be made of such stock it is better to employ only the freshest cocoanut oil for the cold process, although it should be clarified under all circumstances. Next to cocoanut oil in value for cold-made soap is tallow, which is used in the stock in all desired proportions. When no cocoanut oil at all is used, as is the case for making what is known as “Soap Chips” for laundry purposes, it is advisable to add some softer material to the tallow, such as grease, cotton seed oil, etc. In fact, the before-mentioned rule applies here as well, that it is always best to use several kinds of stock together, so as to take advantage of the good qualities of each, and to counterbalance the bad ones. In some cases the addition of a small proportion of castor oil is advisable, as it causes the pro¬ duct to possess greater transparency and an improved texture resembling that of milled soap, and greater durability of the Cold-Made Soap. 273 colors and perfumes. The presence of a small proportion of castor oil is also useful in working- up the scraps, as it facilitates the process of remelting-; or, if the scraps are utilized by milling-, the result of the presence of castor oil is an improved texture of the milled article. When first made, a soap containing castor oil is a little softened by it, but it soon hardens. A material sometimes worked up in this connection is the flower pomades used by the perfumers.. When most of their odor has been extracted, they may be made into a delicately perfumed soap by the cold process. But this stock deteriorates rapidly, owing to the influence of the alcohol used in extracting the odor, and is then very difficult to work by the cold process, owing to the free fatty acids present. For a special quality of toilet soap an addition may be made of wool fat (Adeps Lanae), which does not saponify nor become rancid and makes the soap more emollient. According to its influence on the lathering properties of the soap, in other words, according to the stock used, from 3 to 8 % may be added. The method of applying it is to simply melt it in the warm stock. Such soaps are in the nature of super-fatted soap, but do not be¬ come rancid on keeping. If heated excessively, wool fat (lano¬ lin or adeps lanae) darkens the soap. For further details concerning the selection of stock the reader is referred to the description of different fats and oils (Chapter II), and to the special chapter (VI) covering this subject. PURITY OF THE STOCK. After selecting the kinds of fats according to the well-known properties of the soap which they form with alkali, the purity of the same is of the greatest importance, much more so for making cold-made soap than when they are saponified by boiling. All impurities of the fat must, therefore, have been removed before adding the lye, so that the soap maker may know just what ma¬ terial he has to deal with, and in order that the soap itself may be pure. All fats may be purified before use, in the manner de- , scribed elsewhere, but if very old they should be excluded alto¬ gether in making soap by the cold process, as even purification fails to give good results in that case. As a preliminary step, melting the stock and resting it in a settling tank (as described under “Saponifying the Fat,” in 274 Cold-Made Soap. Settled Soap, Chapter VII), is to be highly recommended, also, • in the cold process, for the purpose of removing the coarser im¬ purities. The extent of the impurities removed thereby can hardly be realized unless the stock is weighed before as well as after settling. Besides the direct loss from very impure or adulterated stock, and the strongly alkaline soap apt to result from it, there is danger of a batch being spoiled altogether in case the fat con¬ tains such impurities as salt, water, sulphuric acid (from render¬ ing), etc., in appreciable quantities. No less important is the absence of free fatty acids from the stock. If old and unprepared fats are used in the cold process, the free acids combine very rapidly with the lye, and in doing so collect in lumps of partly formed soap, enclosing in their mass particles of fat which are thereby prevented from combining with the lye; as a result the product in such a case will be a poor soap, full of uncombined materials, quickly turning rancid, losing its perfume, and appearing smeary and yet sharp at the same time. In making soap under such conditions, the contents of the mixing vessel thicken up quickly, sometimes even before all the lye can be mixed in, and the resulting soap has a coarse texture, whereas a well-made, fine-grained soap results only when the mass is in a condition permitting it to be stirred or crutched for some length of time. Even if the consequences are not always so very noticeable, the soap made from fat containing free fatty acids will always be gritty and coarse-grained, and of generally inferior quality. In order to make uniformly good soap by the cold process, it is therefore always necessary not only to free the stock from all foreign impurities, but also from the free fatty acids, an opera¬ tion so much the more to be recommended as it also bleaches the stock at the same time, and thus causes a marked improvement in the color and clearness of the product, besides improving its quality as a detergent. The purification and bleaching of all kinds of stock for the cold process may be performed by treating the melted fat with a little strong lye and alum and agitating, as described on page 43 for bleaching tallow. If preferred the following process maybe adopted instead: The stock after melting and settling orstraining, is run into any convenient vessel and brought to a temperature somewhat Cold-Made Soap. 275 below 180 F. For every 100 lbs. of stock 2 or 3 lbs. of 36° lye are then run in slowly and stirred in thoroughly for several min¬ utes. The lye will combine with the free fatty acids and the particles of soap forming will enclose and carry with them the other impurities of the stock. After stirring for a few minutes as stated, 2 or 3 lbs. of 22^ salt water are run in and stirred through. The vessel is then covered up (unless the atmosphere is very warm) and the contents are allowed to rest over night for the separation of the impurities. The stock should not be warmer than 180° F. because otherwise the impurities will re¬ main suspended in the oil. When, especially for laundry soap, it should be deemed un¬ necessary at any time to subject the stock to a special process, of purification, the temperature of the stock should be as low as possible when running in the lye; even if at first the soap shows signs of slightly congealing, the heat gradually liquefies it again and the soap may be finished without trouble. This pro¬ ceeding will produce a finer grain than when the stock is com- parativel} T warm. For cocoanut oil it is always advisable, however, to at least boil it up on strong salt water for half an hour, taking off the scum which rises until it comes up perfectly white. At this point the impurities are allowed to settle. QUALITY OF THE LYE. The quality of the lye that is used for making a soap by the cold process is of considerable consequence, and in fact as im¬ portant in a cold soap as in soft soap, Eschweg soap, or in any other soap that is made without a change of lye. It is in cold- made and in half-boiled soaps more than in any other that one can appreciate the force of the definition which explains that soap is “lye, diluted and modified by fatty matters.” But unlike the lyes used for Eschweg and soft soaps, that employed for the cold process is very simply determined: it is at all times to be made of the highest grade of caustic that can be obtained. 76 to 77 % caustic, dissolved in soft water (preferably that condensed from the steam pipes, or rain water), protected from the atmosphere by an airtight covering, and allowed to rest till all impurities have settled out, makes the best possible lye for this purpose. Only when customers demand a very white look- r r J White soap. ing soap, can a lye of low-grade soda be used to advantage, to 276 Coed-Made Soap. which—for cocoanut oil soap—some salt may even be added. Soap made with such lye is really inferior in quality, but it is some¬ times demanded by customers who judge the product by the color. The lower grades of caustic contain impurities in the lorm of salts, especially carbonate of soda and common salt, which are not in any way affected by the fats, and, if the lye is made from such caustic, these salts remain unchanged as impurities in the soap, besides causing imperfect saponification by preventing the caustic alkali more or less from coming into that intimate con¬ tact with the particles of fat, which is necessary for there chemi¬ cal combination. A lye containing much carbonate of soda causes the soap made with it by the cold process to be soft and spongy, and under otherwise unfavorable circumstances may even losen the combination between alkali and fat to such an extent, that the fat will partly separate and collect in the centre of the soap frame, where the soap is the hottest. The same is true with sili¬ cate of soda (unless used in large quantity), and when a moder¬ ate proportion of the latter is used for filling, the soap will have to be run into small frames, so as not to retain too much heat. Besides causing the faulty saponification, the foreign salts have the disagreeable property—especially in winter—of coming to the surface of the soap with the water, on drying, and remaining behind as a dry, white crust when the water evaporates. This makes the soap unsightly, ruins the wrappers, and has a suspicious appearance to the mind of the consumer. To make the lye, the caustic should be dissolved, as said be¬ fore, in pure, soft water. If only hard water can be obtained it would be well at least to boil it and let it settle, as thereby a part of the lime compound held in solution by hard waters is pre¬ cipitated. Or the water may be softened by adding 2 or 3lbs. of caustic soda to 1,000 gallons of water, and letting it settle. A con¬ venient tank for this purpose is one that has a faucet at the bot¬ tom for drawing off the sediment, and another one a few inches from the bottom, for the clear water or lye. When made, the lye should be at a strength of about 35 B. when hot, which will bring it to 38—39° when cold. It can then be diluted further, if wanted, without becoming hot again. If the lye when first made is above 39 : —40 it will become hot again on diluting it, which is generally best to avoid, as warm lye makes less smooth soap. After the caustic has been dissolved, the lye should be ex- Cold-Made Soap. 277 eluded from the air, as the latter always contains carbonic acid, which the caustic alkali absorbs eagerly, thereby becoming part¬ ly carbonated, and consequently reduced in purity and strength in a similar way as if it had been made originally from low-grade caustic. A simple method of protecting the lye in this respect, by means of mineral soap stock, was mentioned in the description of the lye tank, on page 93. Where the facilities are such that this can be done, the lye should be made early enough to give it several days’ time to clarify by resting, and drawn off carefully from the settled im¬ purities. If an occasion should arise when it seems desirable to filter the lye, this may be done by the aid of glass wool, packed into a glass funnel. Some brands of caustic, especially the lower grades, occasion¬ ally furnish a lye of a yellowish tint. For white soaps such lye is not well adapted, as their color is extremely delicate. The color of such lye may be removed by boiling it with 30 lbs. quick lime to each drum of caustic, and letting settle. Formulas for cold soap are usually based on the highest grade (say 76%) of caustic; if for any reason a lower grade is employed, the corresponding amount of the lower grade required may be calculated by multiplying the amount of lye called for in pounds by 76 and dividing by the figure which represents the grade of caustic actually used. As in all soaps, the substitution of a part of the soda lye by potash lye causes a marked improvement in the product of the cold process, as it renders the product milder, better in texture, more readily lathering, and slightly more transparent at the edges. Care must, of course, be taken to get good potash. As more potash is required than soda to saponify a given amount of fat, 7 lbs. of potash lye are generally used in place of 5 lbs. of soda lye. QUANTITY AND STRENGTH OF LYE. The exact amount of alkali required for the saponification of a certain amount of fat has been a matter of considerable spe¬ culation and finespun scientific calculations, but all the latter have been able to do was to prove that for practical work no ab¬ solutely correct figures can be set down, as fats are too variable in their composition and purity. Figures that are correct for a certain weight of, say a given lot of tallow, are not necessarily 278 Cold-Made Soap. correct for the same weight of some other lot of tallow. Then again, so long as the cold process cannot insure the perfect com¬ bination of all the lye with all the fat, there would really not be much advantage even in knowing the figures representing the exact chemical equivalents, for what the soap maker muststrive for is to so gauge the proportions of lye and fat as to make a soap as near as possible in accordance with our conception of an ideal soap. If we must needs employ the cold process for our purpose, then the question is not what proportions would give the best result //they could be combined, but the question is : “What proportion actually does give the best total results?” Some manufacturers, knowing that a certain weight of lye will make a mild soap, deliberately use a slight excess in order to have a product for the laundry or for general housework that will wash quickly. For toilet soaps, of course, the case is some¬ what different, and the manufacturer must keep within narrower limits. Under the circumstances we can give only approximate figures which are known to give good results under careful mani¬ pulation, and state under what conditions, as to strength of lye, etc., the alkali is best employed. Cocoanut oil requires more alkali for neutralization than any other known fat, and for a toilet soap made by the cold process it is universally calculated to require just one-half of its own weight of soda lye, if the latter is of 38 B. strength and made of 76% caustic. If the caustic soda is of a lower grade than 76% then correspondingly more must be used (or the lye is made of about 40° B.) If it is desired to use a weaker lye the quantitv of 38° lye necessary may simply be diluted as much as desired. For tallow, grease, lard, etc., half their weight of soda lye at 36° B. is generally accepted as the proper proportion, they all requiring about the same amount of alkali. For 50 lbs. cocoanut oil and 50 lbs. tallow there are, in a similar manner, calculated 50 lbs. of 37 lye of 76% caustic soda. It will be observed that these amounts are slightly below those named for the half-boiled process, which is owing to the fact that in the latter more can be used, as the combination is more complete. Too much lye makes the soap not only sharp, but also exces¬ sively rough, hard and brittle. Small batches of soap do not develop as much heat as larger ones; they therefore do not com- Cold-Made Soap. 279 bine as thoroughly, and are apt to be somewhat sharper than larger batches made of the same proportions of material. An unfilled soap, made of 600 lbs. stock and 300 lbs. of 38 lye, will have about 25% of water ivy its composition; for 100 lbs. caustic and 200 lbs. water make 300 lbs. lye of about 38° B., and these, with 600 lbs. of stock, make 900 lbs. of soap. Regarding the strength of lye, cocoanut oil and cotton seed oil saponify most readily with that of 38°, but for the other fats it is best to reduce it to 36° B. If the lye used is too strong the saponification of the fat will be less thorough, and the soap will be hard and rough as if an excess of lye had been used. For white cocoanut oil soaps which are to preserve their color for some length of time it may be well to reduce the strength of the lye with water to 36°; the soap will be somewhat softer at first and is therefore hardened by the addition of a little extra lye. This proceeding insures a better saponification and consequently guards the soap against rancidity. To keep the extra water from drying out a small addition of chloride of potash solution at a strength of 15 B. is sometimes also made, or part of the lye used is made of caustic potash. In some formulas the strength of the lye is given, with di¬ rections to dilute it with a certain amount of water. This is done because it is more convenient, and at the same time more exact, to use a certain amout of lye of ordinary strength and dil¬ ute it afterward as required, than to dilute it to a certain degree, to be determined by the hydrometer; the greater convenience is obvious, and the greater exactness follows from the fact that a lye shows slightly different densities, according to whether it is measured just after diluting and stirring it, or after resting for some time. TEMPERATURE OF STOCK FOR MIXING. The fats must be melted, so as to be in condition to mix thoroughly with the lye, and for the sake of economy in time, labor, and fuel, the stock is preferabl} 5 ' used when it has cooled off enough after bleaching it. Cocoanut oil is therefore best melted and prepared at least a day previous to using it; or before, if the quantity is large, so as to give it time to settle and cool. Tallow settles more rapidly and is ready almost immediately after bleaching, except for its high temperature; with the other stock already cooled, if both tallow and cocoanut oil are used 280 Cold-Made Soap. after settling-, the averag-e temperature may be about rig-ht. If for any reason it cannot be arrang-ed to have the stock cool off naturally, it will be necessary to cool it by means of cold water, either by leading- the latter throug-h a coils placed in the settling- tank, or by circulating- cold water in the jacket of the vessel in which the soap is to be mixed. If the stock is to be melted just before using-, it may be ad¬ visable to melt the tallow first, as it requires the greater heat, and then to add the cocoanut oil which melts at a lower temper¬ ature and reduces that of the tallow so that the mixture is just about rig-ht. Cocoanut oil alone may be saponified to the best advantag-e when cooled to about 70-80 F.; a mixture of equal parts, tallow and cocoanut oil, at 100-110 F.; tallow lard, grease, etc., when used alone, at 105-130 : F., according- to their ag-e, etc. Only aslig-htly hig-her temperature is required than would be neces¬ sary to keep the stock from solidifying- on running- in the cold lye, so that the proper temperature depends on the melting- points of the fats. In winter it is best to have the stock about 10° F. hotter than in summer, and to have the lye at about 80° F. If the stock has not been prepared, i. e., the free fatty acids removed, or if rosin is used with the stock, it is necesary to use the lowest possible temperature, as the free acids cause con¬ siderable spontaneous heating- by their rapid combination with the lye. So also must a low temperature be used when the soap is hig-hly filled, and in summer the frames must then not be cov¬ ered very closely. If the temperature at which the ingredients are mixed is too high, those particles of the fat which were first to come into con¬ tact with the lye combine with the latter so rapidly that lumps form before all the lye is thoroughly mixed in, and, these lumps adhering to each other in a mass, the whole batch may be spoiled. It is also worth remembering that a low temperature pro¬ duces a whiter soap, while a higher temperature is more favor¬ able for a certain degree of transparency in the product. The lye is used in nearly all cases at the ordinary tempera¬ ture of the atmosphere, except in cold weather or for old stock, when it is made luke-warm. Some prefer to have both, stock and lye at the same degree, but it is difficult to see any advant¬ age accruing from the trouble of heating up the lye under ordi- Cold-Made Soap. 281 nary circumstances. On the contrary, a cold lye rather favors a greater smoothness in the finished soap. MIXING AND SAPONIFICATION. The actual saponification takes place only during 1 the course of spontaneous development of heat in the frame, and is barely induced while mixing. The stock, at the average temperature best suited to its composition—as just explained—is run into the mixing machine. This machine may be any vessel provided with a suitable agitating apparatus, and consists preferably of a jacketed kettle with a rapidly revolving agitator; the crutch- ing machines described in chapter V. are very suitable for the purpose. The object of this machine being simply to mix the fat and lye as thoroughly as possible, the best results are obtained by having the machine run at a good speed so as to complete the mixing quickly and keep the contents as homogeneous as possible while the lye is running in. For making colored soap, from well-purified stock, so as to admit of long crutching, an ordinary vessel and a hand crutch are frequently preferred, as it is difficult to clean a crutcher from the remnants of the colored soap. The stock being run into the crutcher (which should not be perfectly cold in winter time), the machine is started to crutch and the lye is run into the fat steadily in a thin stream at such a rate that it is all added in three or four minutes for a large batch. Crutching is continued uninterruptedly until the mass isobserved to thicken, so that a mark drawn on the surface remains visi¬ ble for some time and a sample taken out on a paddle runs off slowly and forms thick threads on the surface of the soap. Crutching is then discontinued and the soap run at once into a frame placed under the machine. Some experience is required to )udge correctly just when a soap of a given composition as to stock is in the best condition for framing; if framed too early the soap will afterwards be found smeary in the upper part and very sharp near the bottom of the frame, owing to part of the lye sinking; On the other hand, if the crutching is continued too long, or if too much time is allowed to pass before framing, the mass may separate in the frame and spoil the batch alto¬ gether; the same may happen if the ingredients were either too cold or too hot, or impure. Another proceeding which is preferred by some, although 282 Cold-Made Soap. it is difficult to see any advantage in it, consists in adding only about one-half of the lye at first; when the contents of the crutcher form a homogeneous mass the remainder of the lye is then added. The length of time necessary for crutching varies greatly, but the longer the stirring can be continued before the mass shows signs of requiring framing the finer will the grain of the soap become; in this respect also purified fats have an advantage over those not previously purified, as the former do not combine so rapidly with the lye. The frame into which the soap is run should not be too cold; nor should it be very high, especially if it is of large capac¬ ity, as it would retain too much heat. If the soap is run into a rather large flat frame and covered up with sacks or blankets it will become heated by the action of the ingredients on each other, and saponification will be effected without any further attention being required. In very hot weather cold made soaps —especially those highly filled—are liable to separate oil in the frame if covered up too warm; the temperature which a batch is allowed to acquire is therefore of much influence on the quality of the product and requires some study for each special case to obtain the best results. A soap of a certain composition which turns out well in a 300-lb. frame would be likely to show signs of separating oil in a 600-lb. frame, and would spoil entirely in a 1,200 lb. frame, owing to the greater heat prevailing in the larger batches. It thus follows, also, that whether the frame should be covered, and for how long, depends on the size of the frame, the temperature of the soap and of the atmosphere, and on the composition of the stock, as well as on the construction of the frame—whether of iron or wood. When the heat has ceased to be generated in a frame, the soap may be uncovered in order to cool off more quickly; after then hardening for a day or two it is ready to be stripped. In iron frames it must remain covered longer than in wooden ones which retain the heat longer; if uncovered too early the soap in the frame is apt to be of a different color in the centre than on the sides. A mixing machine has been patented which can be lowered into a frame so as to mix the ingredients therein, using no special mixing vessel. Ordinarly, however, some of the machines de¬ scribed in Chapter V. are used. Cold-Made; Soap. 283 FILLING. Cold-made soaps may be filled with any of the materials enu¬ merated and described in Chapter IV., by making the additions in the manner described for half-boiled soaps. Mineral soap stock, silicate of soda, and talc, are the fillers most commonly employed. The silicate of soda must be prepared with lye in the same manner as described for half-boiled soaps, or an equivalent excess of lye must be used with it. Such soap has a very nice appearance while fresh, but on drying out somewhat acquires a hard surface. As stated before, silicate, especially if it has not been previously prepared with lye is liable to cause separation, or spongy parts in the centre of the frame if the batch is large, so that for such soap it may be necessary to employ frames hold¬ ing as little as 200 lbs. each, and let the frames remain uncov¬ ered. When much silicate is used, however, the frames may be larger, probably owing to the fact that a larger addition tends to decrease the development of heat, by retarding the combination. The silicate, if added to the mass when the materials have joined, would thicken the soapso much that it could scarcely be handled; it is therefore generally mixed with the lye before stirring the latter into the fat, or it is mixed with the last portion of the lye used. A little glycerin or some 15 pearl ash solution is some¬ times used in addition to make such soap a little smoother. Talc , wuich may be used in as large a proportion as 25 or 30 per cent and over, gives the soap a somewhat dull appearance, in white as well as in colored soaps, but it also makes it less hard on aging than one containing silicate with which it is sometimes used together; some manufacturers prefer to boil the talc in a little weak lye before adding-it, claiming that this “opens” the talc and makes the product smoother. Others prefer to simply mix the talc with the oil before running the lye into the crutcher. For cheap soaps made largely of cocoanut oil, solutions of salt, potash, and chloride of potash are largely employed as fill¬ ers in Europe, since cocoanut oil has the property of absorbing these solutions in considerable quantities without separating. These solutions are usually crutched in when the soap has thick¬ ened so as to be nearly ready for framing, and are mostly em¬ ployed at a strength of from 15° to 25 B. Saltwater makes the soap hard on drying and causes it to feel moist if added in more than moderate quantities. Chloride of potash is more expensive, but retains the water of the soap better than does common salt. 284 Cold-Made Soap. In fact, these filling’s must be regarded as simply water, to which the salts are added for the purpose of counteracting the softening effect which simple water has on soap. Potash solu¬ tion especially prevents the drying of soap filled with salt solu¬ tion or silicate, so that potash and salt are generally used to¬ gether; they also give the soap a more transparent appearance, and, used moderately, they enhance the whiteness of cold soaps which otherwise turn yellowish on storing. In European countries cold-made cocoanut oil soaps are also very frequently filled by so-called filling lyes, which are made according to the following examples, and which are used to the extent of from 10 to 50 lbs. to every 50 lbs. of cocoanut oil in the stock: (1) 100 parts water, 14 parts sugar, 7 parts salt, 7 parts pearl ash. (2) A 16 c B. solution of chloride of potash, sal soda and salt (equal amounts of each). (3) One part each of sugar, potash and salt dissolved in 4 Y? parts of boiling water. (4) 85 parts hot water, 9 parts pearl ash, 6 parts salt, 5 parts sal soda. In using these filling lyes the cocoanut oil should not be used warmer than necessary, and the frames are not covered, as the soap would become too hot if covered and would separate oil in the centre. The oil and lye are first mixed, and when the soap is thick and appears ready for framing the filling lye is crutched in. Where these salts are used for filling it is so much more im¬ portant, of course, that the lye be made of the highest grades of caustic. If, on pressing, the soap should show a tendency to crack, as is liable to be the case when much filling is employed, the cakes must be warmed somewhat to soften them before pressing. PERFUMING, COLORING, MARBLING. If properly prepared stock is used, the essential oils for per¬ fuming may be crutched into the soap just long enough before framing to secure their intimate admixture, so as to avoid all unnecessary evaporation during the crutching operation, as well as the action of the lye on the oils. With unprepared stock it may be necessary to add the oils together with the last of the lye. If powdered orris root is added, and it is found to make the soap too dr} 7 and brittle, some of the soda lye should be substi- Coi.d-Madk Soap. 285 tuted by potash lye, or the lye is used a little weaker. Orris root turns the color to yellow or yellowish brown. It should also be remembered that oil of cloves has a peculiar composition, different from other essential oils, and that it is therefore not well suited for soaps made by the cold process, as it interferes with the com¬ bination of the materials, and at all events gives the soap a bad grain and texture and a yellowish color; the latter case is also true in regard to cassia oil, which makes these two oils unsuit¬ able for white soap. (For further details see the chapter on Perfuming and Coloring.) Insoluble colors, such as vermillion, are well mixed with a portion of the oil, and added to the stock from the start; soluble colors, such as annatto, aniline, etc., are dissolved in boiling wa¬ ter, or in alcohol, and strained through a silk cloth into the stock or the lye, to avoid specks of undissolved color. Of the soluble colors much smaller quantities are ordinarily required than of the soluble ones. For yellow soaps a little unbleached palm oil may be used with the other stock. Palm oil in conjunction with orris root and storax causes a natural and permanent reddish brown color which makes this combination popular for cold-made violet soap. White soaps must not be too warm on cutting up the frames, as they are liable to become discolored on exposure to the air when warm. The addition of just a trace of ultramarine will change the yellowish tinge of most white soaps into a less notice¬ able greenish color. For making marbled or variegated soap by the cold process, the water soluble colors are not well adapted, as they run too much. Numerous processes are employed to produce the marbled appearance; for instance, the soap may be run into the frame be¬ fore it has become quite so thick as usual. A sheet iron cylinder, open at both ends, is then sunk into the frame and the soap within colored through the upperend of the cylinder. A wooden stirrer is then used to draw the colored soap into the uncolored portions in streaks, and, lastly, by means of a rod with a round knob on the end, figures are drawn through the whole frame. Another method consists in mixing the colors with a little oil or warm water and stirring this into a small portion of the soap, when thick. A layer of soap is now run into the frame, and the colored soap is spread over it “criss-cross” in a thin stream (as by running it through the stem of a funnel, or a sprink- 286 Cou>Madk Soap. ling- can with larg-e holes). Then follows another layer of the soap, and again streaks of the colored soaps. When the frame has thus been filled by alternate layers, a stick is used to distri¬ bute the color in the soap more finely, as described above. Where the mixing vessel is such that it can be tipped to empty it into the frame, the soap in the upper part of the vessel only may be colored, and the whole then emptied quickly b}^ tilting the vessel, so as to run both the colored and the uncolored portion out alongside of each other. Still another method is as follows: The color is mixed with a portion of the soap and a layer of it poured in streaks over the surface of the soap in the frame. It is then forced to the bottom by means of a JL formed crutch, in the bottom piece of which there are a number of holes. Another layer of colored soap is then treated similarly, and so on till all the color is added. A rod is then used to distribute the color still further. FORMULAS FOR VARIOUS COLD-HADE SOAPS. Although the preceding pages contain all the necessary in¬ formation required for building up a formula to make a soap to suit every purpose, a few ready formulas will probably be found useful by way of illustration. The following are selected to show those of the most varied character, and manufacturers who desire to do so can readily modify the same to suit their own re¬ quirements by giving due consideration to the effect of different materials and manipulations, as has been fully explained. PURE COCOANUT OIL SOAP. 300 lbs. cocoanut oil. 150 “ caustic soda lye, 38 B. This soap lathers very readily, and if carefully prepared Cochin oil and well settled, clear lye are used, the soap will be almost semi-transparent. The lye may be reduced in strength by adding water, until it marks 35-36 B., which will make the soap somewhat smoother and softer; a small extra addition of lye will harden it again and will bring about a more complete sapon¬ ification, so that the soap will preserve its white color longer. By reason of the better saponification this extra strength will not be very noticeable, especially as a pure cocoa nut oil soap can be used (for toilet purposes) only by those whose skin is not very delicate, it being too sharp for tender skins, even if quite neutral. Cold-Made: Soap. 287 As the lather is almost too profuse, and the soap wastes away quickly, a small proportion, say 10%, of castor oil may be desirable, as this addition also improves the texture and trans¬ parency of the soap. FILLED COCOANUT OIL SOAP. The above soap may be filled with silicate, talc, etc., if de¬ sired, in accordance with the directions already given for half- boiled soap, and in the special chapter on filling- materials. About 60 lbs. of silicate (prepared as previously stated), with or without the further addition of 15 lbs. potash solution mig-ht be used; or, if preferred, say 35 lbs. of talc. COCOANUT OIL SOAP, FILLED WITH SALT SOLUTION. 300 lbs. cocoanutoil. 150-160 “ soda lye, 38° B. 30-150 “ salt solution 18 B. Or, 300 lbs. cocoanut oil. 150 “ lye 39-40° B. 25 “ potash solution 20 B. 12 “ salt water 16 c B. In the above two formulas the oil is melted (at about 80- F.) and 135 lbs. of the lye crutched in. When the mass is thick¬ ening- the remainder of the lye, mixed with the salt solutions, is added. If some castor oil is preferred in the soap, it may be added to the cocoanut oil, and the filling- may be varied according to the following formula: 300 lbs. cocoanut oil. 30 “ castor oil. 162 “ soda lye 38 B. 24 “ potash solution 20 B. 18 “ potassium chloride solution 15 B. TALLOW AND COCOANUT OIL SOAP. 240 lbs. cocoanut oil. 160 “ tallow. 200 “ soda lye 37 B. The manufacture of this soap is the same as that of the pure cocoanut oil soap described, only the temperature of the 288 Cold-Made Soap. stock must be a little higher, say 100° F. The tallow will cause the soap to be less wasteful and to lather less quickly than a pure cocoanut oil soap, and will ordinarily reduce the cost some¬ what. Another formula, in which some potash lye is used, and a little less (> 2 ) cocoanut oil, may be adopted, as follows: 250 lbs. cocoanut oil. 250 “ tallow. 240 “ caustic soda lye 38 B. 10 ‘‘ potash lye 38° B. A filled soap which in the eyes of some customers has a better appearance even than the foregoing pure soap, can be made by changing the formula as follows: 240 lbs. cocoanut oil. 160 “ tallow. 200 soda lye 40° B. 60 “ potash solution 20^ B. 20 “ salt water 18° B. A soap of different character results from the following: 275 lbs. lard. 175 “ cocoanut oil. 225 “ 36° soda lye. Or, 100 lbs. cocoanut oil. 50 “ tallow. 50 “ lard. 50 “ castor oil. 120 “ 38° soda lye. 5 “ 26 potash lye., Or, (For yellow soap.) 160 lbs. cocoanut oil. 120 “ tallow. 20 “ palm oil (unbleached). 150 “ soda lye 37° B. The following two formulas and process of making some¬ what similar soaps are furnished by a firm familiar with this class of work. Cold-Made Soap. 289 75 lbs. tallow. 25 “ cocoanut oil (Ceylon). 75 “ caustic soda lye, 35^4° B. madeof 74%caustic. 125 “ “N” silicate of soda. 20 “ pearl ash lye, 36° B. 320 “ soap. Or, 75 lbs. tallow. 25 “ cocoanut oil (Ceylon). 70 “ caustic soda lye, 35}4 ° B. madeof 74% caustic. 100 “ “N” silicate of soda. 17 “ pearl ash lye, 36° B. 287 “ soap. Process. Cleanse the tallow by boiling- on salt brine or a weak solu¬ tion of alum; let tallow settle after boiling-, to deposit all impur¬ ities in the usual manner. Weig-h out the proportion of tallow and cocoanut oil required for a frame of soap into a tig-ht frame. Weig-h out the quantity of caustic soda lye required into a separate vessel. Also weig-h out the proportion of silicate needed into another vessel; also weig-h out the pearl ash lye wanted, which can be mixed with the silicate. When all is ready for mixing-, the tallow and cocoanut oil in frame must be at a temperature of 145° to 150° F. in cAd weather, and 125° to 130° F. in warm or summer weather—the lye and silicate both to be at the normal temperature of factory. When the temperature is as above, run in the lye alone into the tallow and cocoanut oil in frame quickly, crutching- rapidly from bottom of frame all the time. After the ly^e is all in, continue crutching- rapidly till the soap beg-ins to thicken up. Now run in the sili¬ cate and pearl ash lye quickly, crutching- rapidly. As the sili¬ cate mixes with the soap, the whole will thin out. After the silicate and pearl ash lye are in, continue crutching-. In a few minutes the whole will gradually turn creamy. As soon as the soap becomes so thick or creamy that a mark made on surface of soap will remain, it is finished; take out crutchers, cover up frame, and do not move or disturb frame till soap is cold. Any perfume used must be added while crutching- in silicate. 290 Cold-Made Soap. If the frame must be moved from where the soap is made, move it quickly before the silicate is added; then add the silicate at once, and finish soap as directed. This is essentially a quick process, everything’ must be done quickly. For a 1,000 lbs. frame, the lye must be run into the grease material in from 90 to 120 seconds—silicate about the same. Crutching must be done quickly and go to bottom each stroke—work two crutches. Never stop crutching from start to finish. The time for making frame (if the temperatures are right) from 12 to 16 minutes. Great care must be taken not to crutch too long. To insure a smooth soap, stop as soon as a mark made on surface of soap will remain. Under no circum¬ stances move or shake the finished frame of soap until cold. 30% to 53% of refined cotton seed oil can be substituted for an equal weight of tallow, if tallow is hard. If tallow is soft or mixed with grease use less oil. The soap will not be quite so hard, will take longer to harden, and will be a good washing soap. GLYCERIN SOAP. Some soaps are called glycerin soaps by the manufacturers on the strength of the little glycerin only which forms during the saponification of the fat. There is however, also a class of soaps to which some extra glycerin is added, which increases the emollient feeling of the soap and preserves it longer against drying out. Too much glycerin, however, causes sweating and makes the soap smeary. The glycerin is mixed with the melted stock and the mixture saponified in the ordinary manner. If silicate is to be added it may be crutched in after the materials have joined, together with the necessary lye required for preparing the silicate, as the glycerin naturally thins the soap out somewhat. If only little glycerin, or much silicate is used, the latter may be previously mixed with the last of the lye added to prevent the soap from thickening too much. The following is one of a great number of similar formulas: 120 lbs. cocoanut oil. 40 “ lard. 40 “ tallow. 40 “ glycerin. 100 “ lye 38° B. Cold-Made Soap. 201 The fats are melted, and the glycerin added. At about 100° to 110 F. the stock is saponified with 100 lbs. 38° lye. LANOLIN SOAP. 60 lbs. cocoanut oil. 5 “ Lanolin (Adeps lanae). 30 “ Soda lye 38° B. Melt the cocoanut oil, add the lanolin to it and crutch till homogeneous, then proceed as usual to add the perfume, color and lye. This method is preferable to melting the lanolin di¬ rectly, as the latter readily turns dark on heating it. The soap can be further improved and modified by adding to the stock some air-bleached palm oil (and of course a corres¬ ponding amount of lye), and possibly also some glycerin. The amount of lanolin may be increased or decreased with¬ out changing the amount of lye, as it is not saponifiable. LAUNDRY SOAPS. The foregoing formulas are principally intended for toilet soaps. For laundry soaps a smaller proportion of cocoanut oil is used, as the latter is expensive, and the soap wastes away too fast. Naturally, no close distinction can be made between soaps for the two purposes,except, of course, so far as perfuming them is concerned; but the following formulas will be found to be better adapted for household soaps than for toilet purposes: 350 lbs. tallow. 150 “ grease. 100 “ cocoanut oil. 35 “ mineral soap stock. 400-435 “ soda lye 35° B. 300 “ silicate of soda. The mineral soap stock is melted with the fats, at about 120 c F. The silicate is dissolved in the lye, and the latter run into the crutcher while the machine is running briskly. The perfume may be added with the last of the lye. The addition of the lye requires less than five minutes, and, after crutching for a short time longer, the soap will have acquired the proper consistency for framing. This formula may, of course, be changed in many ways, as regards stock as well as filling. A formula, for instance, which gives satisfaction in many localities, is as follows: 292 Cold-Made Soap. 220 lbs. tallow. 35 “ cocoanut oil. 165 “ soda lye, 34 B. 125 “ silicate of soda. Still another formula is as follows: 330 lbs. cocoanut oil. 170 “ tallow. 250 “ soda lye, 39°, diluted with 30 “ water. 350 “ filling', made by dissolving’ 2 parts sal soda, 1 part pearl ash, 2% parts salt, in 20 parts of boiling water. For soaps of this kind, as before mentioned, small and low frames are the most suitable. ROSIN SOAP. As rosin consists of free acids, its presence in the stock causes some difficulty in use of the cold process, as pointed out previously. But this may be overcome fairly well by suit¬ able manipulation. (If desired, the rosin may be purified as de¬ scribed on page 69.) The following are several formulas which have been used for the purpose. 100 lbs. cocoanut oil. 100 lbs. tallow. 200 lbs. rosin. 200 lbs. lye 39° B. Or, 100 lbs. cocoanut oil. 100 lbs. tallow. 25 lbs. rosin. 112 lbs. lye 37° B. 20 lbs. talc (stirred into the stock). <9r, 50 lbs. tallow. 50 11 palm oil. 20 t i rosin. 55 t ^ lye 40 B. 50 silicate of soda. Cold-Made Soap. 293 Or, 255 lbs. tallow (or bleached palm oil). 45 “ cocoatiut oil. 45 “ light rosin. 181 “ 38° lye. 181 “ 38° silicate of soda. The fat and rosin are melted together, strained, and sapon¬ ified, the crutcher running rapidly, and the lye—mixed with the silicate, if any is used—being added slowly; if run in too fast or too warm, the soap will work over. Another method of making these soaps which is capable of giving good results is as follows: Taking the first of the above three formulas as a basis, the stock is melted and worked together with the 150 lbs. of the lye; scraps that are to be worked up may also be added in small pieces, and the whole is melted together. In another vessel the 200 lbs. rosin are melted on 60 lbs. of the lye, and when all the scraps have become melted the rosin mixture is run in slowly while crutching rapidly. The soap must be framed quickly. The lye may have to be diluted somewhat, owing to the dryness of the scraps and the water evaporated during melting. A modified process has lately been proposed, as follows: 80 lbs. cocoanut oil. 80 “ tallow. 180 “ 21° soda lye, mixed with 20 “ 32° potash solution. 40 “ 38° silicate of soda. The fat is mixed with the lye at the ordinary temperature of the atmosphere (60°); then the slightly warmer (72°) silicate is added; the mass then separates. Crutching is continued till all is uniformly dissolved when two pints of strong alcohol are added, which causes the ingredients to join at once. The soap thickens and must be framed quickly. TAR 50AP. 160 lbs. cocoanut oil. 40 “ tallow. 40 “ wood tar. 120 “ soda lye 37B. 20 “ glycerin or vaseline. The fat, tar, and glycerin are warmed up together, and the lye crutched in in the ordinary way. The addition of the glyce- 294 Cold-Made Soap. Remelting. Milling. rin permits longer crutching and thereby a more complete mix¬ ing-. If the soap should separate, warmth and rest will soon close it ag-ain when it may be rapidly crutched and framed. Part potash lye in place of an equivalent portion of soda lye is advis¬ able in case no vaseline or glycerin are used. ^CARBOLIC SOAP. 120 lbs. cocoanut oil. 60 “ tallow. 90 “ soda lye 38° B. 2^4 “ potash lye 25° B. 1 “ crystallized carbolic acid, dissolved in 2/4 “ water. A suitable perfume for this is: oils of lavender 2 parts, white thyme and fennel 1 part each. UTILIZING SCRAPS OF COLD SOAPS. The profitable utilization of scraps is one of the difficult problems of the manufacturers of cold soaps. The most feasible plan is usually the remelting- of the same, as described in Chapter XIV, dealing- with this operation. For factories making-no soap at all by boiling-, this is the more to be recommended, as some remelting- apparatus are excellently adapted also as mixing vessels for the manufacture of soap by the cold process. Where a practicable remelter is not among the machinery in the factory, the scraps are sometimes melted on lye of 24-30° B. and the excess of strength is then absorbed by crutching in an equivalent proportion of cocoanut oil. The scraps may also be remelted in a jacket kettle, by hav¬ ing an open steam pipe leading directly into the soap, keeping the kettle covered up while the open steam is turned on, to pre¬ vent the same from throwing out the contents. By the open steam and that in the jacket, assisted b} T occasional stirring, the scraps are slowly melted. There are then added some salt water and some pearl ash solution, both at about 22° B. (according to the moisture already present in the soap), and in quantity de¬ pending on the composition of the soap, especially as to its pro¬ portion of cocoanut oil. To 150 lbs. of a pure cocoanut oil soap as high as 50 lbs. of each of the solutions may be added. Another use which may be made of the scraps is for milling, if the necessary machinery is on hand. They must be dried for Cold-Made Soap. 295 this purpose, like other soap for milling’, and may be profitably mixed (especially cocoanut oil soaps) with about S% of starch, which will make them more agreeable in use than ordinary cold- mixed soap, or with some talc. For this purpose different colors and qualities of scraps are kept separate, and suitably perfumed in milling. A use which is sometimes made of such scraps in some Euro¬ pean countries is for so-called Mosaic-soap, which is made by making a batch of cold soap of a certain color, and when almost ready to frame, adding the scraps of another color, cut into small pieces and mixing them in well. White scraps are thus mixed with red and brown, and yellow soap, and vice versa. For this purpose scraps colored with aniline colors are not well adapted as the latter has a tendency to spread into the white soap. Another method is a combination of some of the foregoing, as follows: 200 pounds of tallow are melted to 185° F. and 325 lbs. of scrap (free from silicate filling) are then melted in the hot fat. Soon after the mass reaches a temperature of 185 F. again, the scrap will be melted, and the whole is strained into the jacket kettle or crutcher; 110 lbs. of 34 B. lye are then crutchedin. The soap will at first be inclined to form lumps, but thins out by continued crutching. At this stage, some hot water, in which the color has previously been dissolved, must be added, before the soap thickens again. After the lye has all been added, about 45 lbs. potash solution of 25 B. are crutched in. When the soap forms a short, thick mass, it is framed. If the scraps were taken from unfilled soap, the potash solution may be added at once, on melting the scraps, instead of waiting until the lye has been mixed in. Scraps filled with silicate can¬ not be so treated, as the filling would be decomposed, and sand¬ like grains would make their appearance. A simple, but not altogether satisfactory way, consists in simply adding the finely cut scraps to the next batch of similar soap just before framing. The cold process may also be employed for making soft soap, by using soft stock and potash lye instead of soda lye. It is un¬ necessary to give a detailed description of the same, however, as there is little call for it, and the details will readily suggest themselves from the special chapters on Soft Soap and on the Cold Procees. Mosaic soap. Another method. . . PART III. CHAPTER XIV. Remelting Soap. When soap that has been hardened by cooling- is subjected again to a warm temperature, it will assume a thickly fluid con¬ sistency similar to that which it originally had when framed. Advantage is taken of this property for melting over the trimm¬ ings left from cutting up the frames of soap, or for working over any soap which may have become “cracky” in the frame, or which is unsalable for any other reason. In England remelting is also largely employed for making toilet soaps from stock soaps which the soap manufacturer furn¬ ishes to the perfumers and others for remelting, coloring, per¬ fuming, etc. This practice was the natural outgrowth of the excise regulations governing soap factories formerly in force in England; but in the United States remelting is practically con¬ fined to the utilization of scraps and faulty soaps, as stated above, or for making small batches of floating soap. In factories where soaps are made by boiling, the scraps may be utilized in the manner described at the close of Chapter VII (Settled Soaps), but owing to the reasons there explained, remelting is greatly to be preferred. During remelting the soap assumes a condition in which the use of a small amount of extra filling is not only possible, but even advisable, inasmuch as this “closes up’-’ the melted mass, giving it a more even and solid texture—besides increasing the weight of the soap. For factories making soap only by the cold process, remelt¬ ing is really the most feasible plan for utilizing the scraps. The manner of remelting necessarily varies with the ma¬ chinery employed for the purpose, and it may here be remarked 300 Remeeting Soap. Soap a bad con- ductoi' of heat. that practical soap makers are by no means equally successful in the use even of the same machines for this purpose. The differ¬ ent apparatus described in Chapter V, as used for remelting, give good results when correctly used. More than on the ma¬ chinery, however, the results depend on the character of the soap to be remelted and on the judgmentexercised in the operation, especially when the soap contains much filling. The principal point to remember in remelting is that soap is a bad conductor of heat. For this reason the operation must either be allowed plenty of time, or the remelted soap must constantly be moved away from the steam-heated parts of the apparatus, so as to make room for the unmelted scraps directly near the hot parts of the machinery. All attempts to hurry the process will be unsuccess¬ ful if the arrangements are not such that the scraps are directly in contact with the source of the heat. Referring to the various illustrations in Chapter V, the pro¬ cess of remelting is conducted as follows: The machine is filled with the scraps and the kettle covered up (or the curb described in Chapter V is used), in order to pre¬ vent the steam from escaping into the room, and to thoroughly moisten the soap; open steam is then admitted into the contents until the scraps are beginning to melt. Scraps that have become well dried before remelting will melt less easily than soap still containing a considerable propor¬ tion of water; with the latter it may not be necessary to add any open steam at all. When toilet soaps are made by remelting stock soaps (cut into shavings for the purpose), it may also be best not to use open steam, as these soaps are generally intended to contain but little water, so that they may resemble milled soaps as much as possible. If a combined crutcher and remelter is used for making a toilet soap by remelting, without the use of water or open steam, the conveyor screw should run very slowly. Half a day or more is required in this case for remelting a frame of soap. For ordinary uses, with the aid of open steam, the operation proceeds much more rapidly, however. When the soap is observed to begin melting, the open steam is shut off and the closed steam turned on, so as to heat the iack- et, or coils, as the case may be. In the Whitacre remelter (Fig. 43) the soap, as it melts, is run off into the frames, and the con¬ tents of the latter occasionally stirred up, to insure uniformity of the mass, or the soap is run into the crutcher for mixing. If Remelting Soap. 301 the machine used is a combined crutcher and remelter, more scraps are added as the soap melts down, and the crutcher started for a few minutes until the melted soap and the fresh scraps are well mixed. Closed steam is then again turned on to melt the soap completely. The open steam should be employed in such manner that it Open ste;u». supplies only enough water for giving the remelted soap the or¬ iginal appearance and consistency of a newly made soap, and no Crntchiug. more crutching should be done than is required to secure even melting of the scraps; too much crutching will make the soap frothy by incorporating with it air bubbles, which will cause it to float. The same defect results also if the soap is crutched long when very thick, or if it is heated for too long a time, whereby it undergoes a peculiar alteration in its texture. Ex¬ perience is here again the only reliable guide. Care must, of course, be taken that no unmelted pieces re¬ main, as they would cause aspotted appearance, especiallv if col¬ oring matter or filling is to be added. After simply remelting, the soap has not exactly the same Additioiiad fiiiiug. appearance and consistency as the original soap from which it was made, and to improve it in this respect some filling is gener¬ ally added while crutching, after enough soap for a frame has been melted. The filling may be used similarly as in framing the original soap, and consists of various salts in saturated solutions—as, carbonate of soda, sulphate of soda, borax, salts of tartar, com¬ mon salt, bicarbonate of soda, carbonate of potash, etc., accord¬ ing to circumstances. A favorite material, especially in good soaps, is pearl ash (carbonate of potash) dissolved in water, which causes the simultaneous formation of carbonate of soda and of potash soap in the mass, thereby very noticeably improving the texture of the product. (This change is similar to that men¬ tioned under “Potash,” in Chapter III, and further explained in note 11 of the Appendix.) For a good toilet soap such an addition of filling is, of course, out of place, and, in fact, toilet soaps are best made by milling, which is the usual process in this country; while the cheaper grades of this kind are generally made by the cold or the half- boiling process. The stock for remelted toilet soaps would have to be selected according to the product to be made. A settled soap made of 302 Remelting Soap. tallow and a small proportion of rosin, a small proportion of co- coanut oil soap—to increase the lathering- properties—white curd soap, and, perhaps, also some soft potash soap, may be blended tog-ether by remelting-, in proportions to suit. A clos¬ ing- mixture, consisting- of a saturated solution of say 12 lbs. pearl ash is then crutched in for .every 1,000 lbs. of soap, and the color and perfume added. The mass is then run into frames. CHAPTER XY. Milled Soaps. General Remarks. Of all soaps made those properly prepared by “milling-” are the best in many respects. In point of intrinsic merit as a soap they are preferred because they contain the least possible amount of water, and are usually prepared from the best materials, and with the greatest care; besides every well-made soap is improved by repeatedly re-working- it. Owing- to the extra time, the special machinery, and the quality of the ingredients required to make the really g-ood kinds of the milled soaps, they are nat¬ urally somewhat more expensive; but they are also more lasting- in use, because their small proportion of moisture and their dense texture make them waste away less quickly, while in point of neutrality and delicacy of perfume they are unequalled by any other soap. In appearance also, which is a not unimportant item in a toilet soap, they are beyond comparison, for the pro¬ cess by which they are manufactured g-ives them a hig-h finish and preserves them from shrinking-, no matter how long-they are kept. These remarks, of course, refer only to those soaps that have been made with that care and of such purity as are looked for by the buyer of milled soaps; they do not apply at all, or at least not in the same degree, to those milled soaps, for instance, that are sometimes made from a cold-mixed soap, either for the pur¬ pose of working- up the scraps, or for the sake of merely g-iving- a cold-made soap the appearance of a milled soap; nor do they apply to some boiled soaps whose ingredients or manufacture have been faulty. Superiority of milled soap. 304 Milled Soaps. The process of milling - itself is merely a mechanical opera¬ tion to which a well-boiled soap is subjected, but the improve¬ ment effected by it is quite important. It consists in preparing* the soap by dr}dng until only enoug*h moisture is left to enable it to form a compact cake, grinding - it between rollers to make it perfectly homog - eneous, and adding - to it—while grinding - —the perfumes and colors, whereby the admixture of these ingredients is made not only more intimate, but also at a considerable saving of perfume, of which more or less would be lost by evaporation if crutched into the hot soap. An additional advantage arises from the exposure of the shavings to the air for drying, during which any free caustic alkali that may be present is converted into the less corrosive carbonate by the absorption of carbonic acid from the atmosphere. Incidentally, however, milling also offers an opportunity for greatly adulterating soap; by the use of starch, talc, and other dry powders, a well-appearing piece of soap may be made even if the stock soap is not quite dry. In an emergency, when the pure soap is troublesome in milling, the addition of from 5 to 10% starch will frequently be very help¬ ful; but for purposes of adulteration the addition is some¬ times increased to as high as 30 or 40 per cent. So also the pro¬ cess of milling may be used to incorporate into the soap such special ingredients for special purposes as vaseline, lanolin (or other wood fat preparations), &c. Early methods of milling. The process of milling originated in France, where it was at first carried on in the following primitive manner: The soap was made into shavings by drawing the bars across an ordinary carpenters’ plane so placed—cutting edge up¬ ward—over a marble mortar, that the shavings fell into the latter. In the mortar they were pounded into a doughy mass, and the color and perfume rubbed in by means of a wooden pestle and several hours of hard work. Small quantities of the mass were then weighed out to form cakes of the desired size, moulded by hand into a form approaching that of the cake, and after dry¬ ing for a day pressed by means of a hand press. The soap so made soon gained a wide reputation, in consequence of which the special machinery for making it in large quantities has been perfected, and milled toilet soaps now have a world-wide reputa¬ tion and are manufactured wherever soap making has become an important industry. Milled Soaps. 305 STOCK FOR HILLED SOAP. Only fresh and pure fats and oils are suitable for this pur¬ pose, for the delicate perfumes and colors would lose the princi¬ pal part ol their value, if combined with a soap of the peculiar odor and appearance arising* from old or low-grade fats. It is also necessary that the fat be most thoroughly saponified, for any free fat remaining would soon cause rancidity in the soap and thereby spoil the perfume. No amount of care in milling can save the soap from deteriorating and the odor from becoming disagreeable, if the soap itself was not well-made in boiling. Trouble of various kinds arising during the process of milling also is in most cases due to faulty manipulation in finishing the boiling, for unless the soap has been very thoroughly settled, it will not adhere together after milling. A good soap for milling should not be too short and brittle, and while it is still fresh it should adhere together on kneading it between the fingers, like soft, tough clay. Tallow, or bleached palm oil, and from 10 to 20% of cocoa- nut oil make the most desirable stock for a soap that is to be made into a milled toilet article. Olive oil and olive oil foots also form soap of a desirable quality for milling and are used to quite an extent for this purpose. The fats are saponified by boiling repeatedly with lye and then settling carefully. The process for making a “White Settled Soap,” asdescribed on page 205, etc., is excellent for this purpose. The fats are saponified in the first change, so that the soap remains sharp after boiling for half an hour, without the addition of more lye; it is then grained, not too strongly, but so as to just separate the waste lye clear on the paddle. After a sufficient rest the lye is run off, the mass closed up again with weak lye of say 8°, and boiled for an hour or two. It is then again grained by strong lye of about 35°, this time so as to have a somewhat sharper grain. The lye is drawn off again after a rest of several hours, and saved for use in laundry soap, and by means of boiling water and open steam the soap is then thinned out for settling; it should not be thinned quite so far as to close up completely like a rosin soap, but only to form a very flat grain. After resting as long as pos¬ sible, the clear soap is framed. In regard to properly settling soap that is to be milled after ward, there is much diversity of opinion arising from the fact Saponification. Settling. 306 Milled Soaps. Special stock. that, when no starch, rosin soap, or other binding’ material is used, the soap will be cracky on coming from the plodder, unless the nigre and foreign salts have been settled out very thorough¬ ly. In order to remove these impurities as nearly absolutely as may be, different means are adopted by different soap makers, and this is one of those particulars in which the most expert have “agreed to disagree” most decidedly. Most manufacturers simply settle the soap as just described, making as large batches as possible at a time, in order to give the soap the benefit of as long a rest as possible to drop the impurities, and using, if necessary, some special ingredients to secure greater cohesion between the particles of soap in case it is defective in this respect. Others hold that the presence of some pearl ash or soda ash in finishing the soap contributes to a more thorough settling out of the impurities, and accordingly they adopt this method of settling soap intended to be milled. Again, still another proceeding is used by some well-known manufacturers of first-class soap which consists in running the hot soap into wooden frames, and allowing it to drop the nigre there. When the soap has hardened and is cut up, it is found that the nigre has been forced upward toward the center of the frame, where it is plainly visible, and may be cut out. The cause of the rising of the nigre in this manner from the bottom of the frame is not as yet fully explained, but it may be com¬ pared to a similar action which sometimes occurs in the kettle after steam has been turned off and boiling ceased. This pro¬ cess makes it necessary to return on an average about one-third of the soap into the kettle, and is consequently somewhat un¬ pleasant and laborious, but the pure soap obtained is in a first- class condition for milling. At any rate, if on cutting up a frame nigre is found in spots, such pieces should be at once rejected, as after drying they are hard to identify. A palm oil soap made in a similar manner as described above, from bleached or unbleached palm oil, is a very useful one for milling purposes, as is also a cotton seed oil soap which may be used to advantage as an addition to other kinds, when the soap in the plodder does not work satisfactorily. The advantage of using some castor oil in soap for milling has already been men¬ tioned in the description of that oil. Where scraps of cold-made cocoanut oil soap are to be worked Milled Soaps. 307 up by milling, it may sometimes be done to advantage by using a soap boiled from tallow alone. THE MILLING PROCESS. The soap, after it has been stripped and cut, is dried for about a day in bars, and then cut into thin, shavings by a ma- Chippin « • ■i • SOtip* chine called the “chipper,” such as illustrated on page 163. Only as much soap should be cut as can be used up in a day or two after drying, for it has been found that from shavings exposed to the air too long a time, the finished soap will have a less beau¬ tiful finish. The shavings are then spread out in layers to dry, and if possible are placed on sieves for this purpose, so as to dry as evenly as possible. The process may be conducted in a dry¬ ing room heated by steam, or simply by exposure to the air. In the latter case its duration is very indefinite, requiring, accord¬ ing to the weather, from 2 to 5 days, while in the former it may be finished in from 12 to 24 hours. The proper degree of drying is somewhat difficult to judge, Dr *’ ir) s- and it takes some experience to regulate it correctly. While in bars, a settled soap, made as described, will contain about 35% of water; for milling it has been found that about 18% of water is the best proportion, so that about one-half of the water pre¬ sent in the freshly cut shavings must be evaporated in drying, in order to obtain the best results. Insufficiently dried soap will be smeary and streaky, blisters readily and comes very easily and rapidly out of the plodder; in drying out afterwards some of the perfume will escape, along with the evaporating moisture; but if the drying be overdone the soap will be wanting in the necessary cohesion and will consequently be cracky as it comes from the plodder; the machine will work heavily, and only by heating the nozzle considerably can the soap be made to hold to¬ gether at all. Unevenly dried shavings will require more milling in order to make the mass homogeneous; if this is neglected the cakes will be of uneven density, will therefore not dissolve even¬ ly, and consequently show a ruffled surface and streaky appear¬ ance in use. The best and most reliable method of ascertaining the proper degree of drying consists in slightly overdrying the shavings at first, and then carefully adding the necessary amount of water as the soap may require. Some use shavings of fresh soap in place of water for this purpose. Additions of material other than soap proper, as talc, starch, and the like, will natur- g the 308 Milled Soaps. Perfuming a coloring. Milling. The plodder. ally modify the precise proportion of moisture required in the stock soap in order to have it of the proper consistency and texture. a Before adding- the color and perfume, the shaving's are passed once throug-h the mill, as the soap will pass better through the rollers—which must be set a little further apart this time on ac¬ count of the larg-er sized pieces—if there are no additions made at first which make the shaving’s slippery; besides the perfume and color are distributed more thoroug-hly in this manner. The soap, as it comes in thin ribbons from the mill, is run into a box which is lined either with zinc or lead, and the pre¬ viously calculated quantity of color and perfume is mixed in as well as possible. If insoluble colors are used they are conveni¬ ently tied up in a cloth of open texture which is then shaken from time to time over the soap as it comes from the mill. Some soap makers prefer to add the perfume after the color has already been well ground in, to save it from going- through the mill so often, as it is in this manner sufficiently well mixed with the soap with less opportunity to evaporate. The mass is now again ground in the mill, the rollers of which are set a little closer than they were the first time. This process of running the soap through the mill is repeated several times, according to the number of rollers on the machine and the condition of the soap, say about four times through a five- roller machine, until the mass is entirely homogeneous and free from streaks. The last time it comes from the rollers as thin as paper. With some practice the appearance of the soap as it conies from the mill can serve as a fair indication of its proper condition for the plodder; if too dry it has a strong lustre and little scales are apt to form here and there. If, while on the mill, it should be found that the soap is not dry enough after all, the proceed¬ ings must be stopped to permit further drying, unless some over- dried scraps are on hand to be milled in. From the mill the soap passes without loss of time into the hopper of the plodder. This machine feeds it automatically into a compartment where it is subjected to an enormous pressure, forming it again into a compact mass, and driving out all air bubbles. On the end of the machine opposite the hopper there is a nozzle into which a die of any desired shape is set, so that the soap is forced out through it in one continuous bar of any Milled Soaps. 309 desired form, so long- as the supply in the hopper is kept up; the shape of the nozzle used corresponds approximately to that of the cake to be pressed from it, a number of differently shaped nozzles being provided for the purpose. The end of this nozzle is kept warm, either by a direct flame or by a steam pipe placed around it, as the heat so applied makes the soap come out smooth and glossy. A good, pure soap, made mostly of tallow, will have a better finish with more heat at this part of the machine than one that is made of more cocoanut oil, and, perhaps, even containing filling. If too warm it will cause a streaky and rough finish if the soap is too soft, or blistered if too tough. The first few feet of the bar issuing from the plod¬ der must be returned to the hopper or mill, as they are not suf¬ ficiently compressed and would therefore be apt to crack after¬ wards, as is also the case if the soap shavings had been too dry. From the continuous working of the machine under high pressure the interior parts of the plodder may become heated, causing the soap to be blistered and otherwise unsatisfactory; some plodders have therefore been provided with a cold water jacket. However, as this operates on the soap in the first place, instead of on the heated parts of the machinery, it is better to stop work till the machine cools off. Sometimes, for some reason or other, the soap comes from the plodder wanting in the proper degree of pliancy. At such times the very careful addition of a little glycerin to the soap, on its last passage through the mill, may remedy the defect. Some cotton seed oil soap, added to it, may also be of benefit; or if the trouble arises from overdrying of the shavings, some water or shavings of fresh soap may be incorporated by thorough mill- in°\ Others again resort to the use of a few pounds of mineral soap stock, or melted bees’ wax, paraffine wax, or rosin soap. The addition of some (pure) gum tragacatith, which has pre¬ viously been made into a mucilaginous mass with water, is to be highly recommended in this connection, as it improves the lather and holds the soap together, preventing cracking. In like man¬ ner may be added 3-10% of pure wool fat or lanolin, if the soap is not to be of a pure white color, lanolin giving it a creamy tint; in this case the soap is dried more thoroughly before milling than when such an addition is not to be made. Should this addition make the soap streaky, it is necessary to previously rub up the wool fat with an equal amount of water. Heating the noz zle. Heating of plod¬ der. Remedying d e - feets in the soap 310 Milled Soaps. Pressing. New system ma¬ chinery. Difference in per¬ fuming various soaps. Quantity of per¬ fume used. Mixing of per- f u m e s before adding. A cutting machine with a single wire is placed so as to cut the continuous bar into convenient lengths, corresponding with the size of the cakes, and after a very short time for drying the soap is ready to be pressed. On pressing cakes of milled soap, its peculiar texture is made very prominent through the change in the shape of the bar, whereby the difference in the grain of the ends and the sides re¬ spectively—caused by the action of the machinery—is plainly shown by a mark. A machine has been patented for pressing cakes directly from the long bar, cutting off the soap required for a cake by the die, to obviate this mark. A system of milling soap as it comes from the kettle, with¬ out intermediate framing, has been briefly described in Chapter V, but as it is not as yetextensively used in this country, further details may be omitted. (See illustration opposite page 103.) PERFUMING MILLED SOAP. The subject of perfuming soaps in general will be treated hereafter in a special chapter (XVI), but a few remarks, which refer especially to the milled soaps in which the proper perfume is so important for their success, may find place here. The composition of the oils and tinctures when incorporated into an odorless, well-made soap by milling, retains its original odor unimpaired. In this respect there is a great difference be¬ tween milled and cold-made soaps, for, in the latter, the perfume undergoes a change,• no doubt induced in the course of the chem¬ ical reaction of the lye on the fat. A formula which gives a satisfactory and even elegant perfume for one, may therefore be far from making a pleasant odor for soap of the other process. It has further been demonstrated by practical experience that milled soap requires a larger quantity of perfume than does cold-made soap, in order to make the odor equally prominent; this is undoubtedly owing to its more intimate incorporation by milling, and is amply repaid by the increased durability of the odor. Instead of mixing the oils directly with the shavings, which causes a considerable loss by evaporation, the ingredients for the perfume may be mixed previously with a small amount of pure, odorless, white vaseline. Some manufacturers also use some orris root in the dark-colored milled soaps, one pound of which (for every 100 lbs. of soap) is made with the perfume and vaseline Miixkd Soaps. 311 into a dough-like mass and mixed with the shavings after they have passed through the mill once or twice, the idea being to add the perfume as late as consistent with thorough incorporation, so as to prevent evaporation of the costly ingredients as much as possible. Orris root and a carefully proportioned small quantity of liquid storax (either alone or melted together with the vaseline) make an excellent base for all perfumes in milled soap, making the odor more pronounced and more lasting. The same is true of the tinctures of benzoin, tolu, and civet. Tincture of musk also acts in the same manner, and where the price of the soap will permit it, should always be used for bringing out the per¬ fume, and for making it lasting. The tinctures named should be used in a somewhat more concentrated form than is usual when they are employed for handkerchief perfumes. Lasting qualities of perfume. ' I - CHAPTER XVI. Coloring and Perfuming. At the present time, when so much weig-ht is placed on the outward appearance of the soap, few kinds are on the market which are not more or less eleg-antly perfumed—especially those intended for toilet purposes, which are in many cases also colored. An agreeable perfume is frequently taken by the consumer as proof of a superior article, even thoug-h, as a matter of fact, it sometimes is rather the means of hiding- a naturally disagree¬ able odor. Colors likewise can hardly be said to be of any actual, practical use, and in the case of a few may even be objectionable rather than otherwise. However, since the demand for a soap is g-enerally increased by the judicious use of suitable color and perfume, their employment has become nearly universal. COLORING. The manner of applying- the colors has already been de¬ scribed under the various processes of manufacture, so that only a few remarks about the colors themselves remain to be made. For the sake of the g-ood quality of the soap, if not for econ¬ omy, it is always advisable to use only the smallest amount of coloring- material that will g-ive the required shade, and to select the shade in harmony with the perfume and name of the soap. Thus a “Rose” soap is naturally colored red, “Lily” soap is left white, “Vanilla” soap should be brownish-yellow, and so forth. ’ A . * . Division of colors. The colors used may be divided into two classes: those which may be added in solution (in water, lye, hot soap or alcohol), and those which form an insoluble and impalpable powder and are nearly all of mineral orig-in. Some aniline colors that are 314 Coloring and Perfuming. insoluble in alcohol, as well as in water and lye, dissolve readily in oil sassafras, or in a mixture of oil sassafrass, alcohol and glyce¬ rin. For transparent soaps the insoluble colors are of course unsuit¬ able. (Tampico yellow and Uranine are much used for them). Soluble colors, as a class, produce much handsomer effects than the insoluble ones,while the latter have the advantage of permanency which is lacking in most soluble colors. From another view colors maybe divided into perfectly harmless colors and those whose use although ordinarily also harmless, may under certain circum¬ stances—as when used by a person afflicted by some skin disease —give rise to unpleasant symptoms. The latter class is composed especially of those colors containing poisonous metals (mercury, lead, copper, arsenic), which are sometimes employed because they remain unaltered by time and exposure. Vermilion (red lead) and many kinds of aniline colors are of this class. It is also necessary to remember that many of the aniline colors are affected by alkali and therefore do not admit of use in such an article as soap. Natural color of Besides the colors added, we must mention the natural tints of soap made from certain stock, as reddish-brown from crude palm oil, yellow from rosin, greenish from hemp and olive oil, etc., and the brown color caused by the action of heat and lye on the sugar in transparent soap, and by impurities in crude potash. The special colors used for soap are of an enormous variety, and yet a few colors, used either singly or in combination with each other, are sufficient to make up the principal shades desired. White soaps are simply uncolored, but require great atten¬ tion and the most scrupulous cleanliness in their manufacture, as their white color is extremely delicate. When they have natur¬ ally a somewhat yellowish hue, the addition of a very small trace of blue (ultramarine) will change the shade to a light greenish, which is at all events preferable to yellow and less noticeable. (Ultramarine is used in the same manner by sugar refiners and others, to improve the appearance of their product.) Artificial colors Gray soap in all shades is made from white by the addition of and shades, varying quantities of black color, such as Ivory Black, nigro- sine, &c. Brown , in a great variety of shades, is produced by Sugar Color, Brown Ochre, Cutch, Chocolate, Umber, Burnt Sienna, Coloring and Perfuming. 315 Turmeric, Soudan brown, etc., and these may be all modified by the addition of yellow colors, producing - an immense variety. Yellow colors are also numerous, chief among - which are Saff¬ ron, Cadmium Yellow, Annatto, Picric Acid, Naphthaline Yel¬ low, Orang-e and Yellow Aniline; and for special shades also Turmeric and Bichromate of Potash. Sometimes crude palm oil is used in soap for the sake of its color and odor. Turmeric turns brown by the action of lye. Lemon Yellows, for transpar¬ ent soaps, are fluorescine and quinoline. Red is produced by Indian Red, Venetian Red, Aniline Red, Vermilion, Alkanet, Carmine, Bole, Colcothar, etc. Blue soap is now almost exclusively colored with Ultramarine in preference to Indigo, which was formerly much used. Ultra- marine is also used in combination for shades requiring - blue. Methylene blue is also much used. Green is produced by mixing - blue and yellow colors, as saff¬ ron or Chrome Yellow and Ultramarine; or Guinet’s Green is used, Chlorophyl, which however, fades on exposure. For soft soap the use of hempseed oil is sufficient to make the product green. Sligffitly bluish green are improved by the addition of some yellow color. Orange is made by mixing - yellow and red, or Mineral Orang-e is used as a color. Purple is a mixture of red and blue. Other shades in great number are produced by the aniline colors, such as Fuchsin, Eosin, Bismarck Brown, etc., and by mix¬ ing - several colors. For instance, Buff is produced from mixing - turmeric (1 part) and bichromate of potash (2 parts), dissolved in lye. Special Yellow tints are made by combinations such as: Yel¬ low Ochre 5 ounces, Burnt Sienna 10 drachms. Or: Yellow Ochre 1 ounce, Orang-e Mineral 1 ounce, Gambog-e 5 drachms. Still another shade is made of: Brown Ochre 1 ounce, Ver¬ milion 2L? drachms, Ivory Black ^ drachm. An olive color is made from green with a very little red. And thus the combination may be carried on without end. Some of these many coloring - matters, at least, deserve a few additional remarks: Cinnabar , a firy red color, is a compound of mercury and sul¬ phur (the sulphide of mercury) and insoluble; it has a hig-h specific gravity—a fact worth some attention when this color is 316 Coloring and Perfuming. used in cold-made soap. It is not infrequently adulterated with oxide of iron, plaster of Paris, &c. Chrome Red is a compound of chromium and lead, varying in shades according to the fineness of the powder. It is sometimes used in place of cinnabar, although its best shades are those of a powder almost too coarse for use in soap. Carmine is a more or less firy red powder, obtained from the Cochenille insect; soluble in ammonia. Chrome Yellow, chromate of lead; has a high specific gravity (a point to note in cold-made soaps); as this color sometimes causes black spots in the soaps, it is not so suitable as cadmium yellow which, however, is much more expensive. Cadmium Yellow is a compound of cadmium and sulphur and a very useful color, being absolutely permanent, though ex¬ pensive. Cur cumin, orange yellow crystals obtained from the curcumor root grown in East India, China, &c., soluble in alcohol and oils. Orlean Yellow , a product from the fruit of a South American tree; not readily soluble in water, more so in alcohol with which it forms a beautiful orange solution; with alkalies it gives a dark red. Saffron is a yellow color derived from flowers; it is very sensitive to light. Ultramar in, first found in a rare mineral (Lapis Lazuli), is now made from Kaolin by treatment with soda, sulphur, and carbon. It is unchanged by the action of air, light, and soap, and even improves by the exposure to air, but is very sen¬ sitive to acids. Berlin Blue , though used in perfumery, is destroyed by the action of soap. Indigo , a dry, vegetable product of dark blue to violet color; the powder is insoluble in water, alcohol, acids, and alkalies. It is rarely used now in soaps, being mostly superceded by ultra- marin, but a special compound of it, known as Indigo carmine, is used more often, especially to produce green colors in com¬ bination with some yellows. Guignefs Green is product of bichromate of potash and boracic acid. Ultramarin Green is an intermediate product of ultramarin blue manufacture. Chlorophyll is the green coloring matter of plants; it gives Coloring and Perfuming. 317 very beautiful shades of green and of course is not poisonous; very soluble in oils, but of little resistance to atmospheric in¬ fluences and light. Umber is a natural brown mineral color, found in many places, but especially near Siena (terra di Sienna) in Tuscany. Catechu , also called terra japonica, is not a mineral color as might be inferred from the latter name, but derived from the wood of a tree grown in Bengal; soluble in alcohol and hot water; dark red to brown. Gambir is almost the same as catechu. Tannic acid in watery solutions colors soap brown, darkening as the soap cools. It affords some desirable shades, but cannot be used in milled soaps. Sugar Color or Caramel can be used in milled soap, soluble in water. Coal Tar Colors. Of the extraordinary large number of coal tar colors a great many are unsuitable for soaps, either because they are decomposed by lye, or because they are insoluble in fats and soaps. Some can be made available by dissolving them with the addition of a small amount of alcohol, others by dissolving them in oleic acid (the acid reaction of which renders some basic colors soluble by forming salts of the oleic acid); turpentine also has a similar effect on some of these colors. Such colors prepared ready for use in soap are in the market in great num¬ ber. One of the earliest known aniline colors was Fuchsin, a very intense color of bluish red; other useful reds are Eosin, Erythrosin, Rhodamin, Bordeaux red, &c. The watery solution has a characteristic greenish efflorescence which, however, dis_ appears when used in soap. Among the yellow aniline colors those particularly worth mentioning are Uranin, Naphthaline, Chinolin, Resorcin yellow, Martinsyellow,&c. Picric acid which also belongs into this group, is too poisonous to be used for soaps. For blue soaps an aniline color known as Alkali Blue may be used; as it becomes lighter when exposed to lye, and darker when the lye becomes neutralized by the fat, the real color ap¬ pears only when the soap is finished, so that care is needed to prevent a darker shade than expected. Another blue is Methyl Blue which fairly withstands the action of light and affords some nice green shades when mixed with yellow. Still another useful preparation of this kind is Victoria Blue. 318 Coloring and Perfuming. Methyl violet, one of the most intense of all anilin colors is one much used for violet soap, as is also Indulin also an anilin color. Anilin greens are also numerous; among- them is Victoria green, but this as well as Naphtol green and the other greens are too sensitive to light, so that most green soaps are preferably colored by suitable mixtures of blue and yellow. Among the brown colors Bismarck Brown is the best known, there being but few anilin browns. As the anilin colors, as stated before, are not very soluble and such helps as alcohol, turpentine, &c., are not always desirable, there has sprung up an industry of making specially prepared soap colors which readily dissolve in oils and fats or even in slightly alkaline water. These colors come mostly in the form of amorphous powders and sometimes in the form of a paste. Their manufacture is in few hands who guard the same as trade secrets, and they are not equal in coloring power to or¬ dinary anilin colors. As these colors require various means of applying them, nothing can be said here on that point, the con¬ sumer being obliged to follow the directions furnished by the manufacturer with each kind of color. As regards their secret process, of manufacture, it is claim¬ ed by some who might be supposed to know, that in the case of some of these colors they are made very cheaply by suitably mix¬ ing those bought from the anilin color factories and “improving” them by the truly secret process of mixing in flour,starch or salt. Thus a beautiful red color of commerce is said to consist of rhodamin 1 part, starch 79 parts. The first anilin colors made were poisonous, but improve¬ ments made since were such that many of these colors are now used for articles of food even, so that with few exceptions there need no longer be any hesitancy in using them in soaps. It may also be mentioned that, since most of these products are very complex in composition, they have been given short trade names by which they are usually known and which we have used in the foregoing for that reason; thus a color ordinarily known as Soudan would, if called by its proper name, become: Anilin-azo-beta-naphthol; and Malachite green is “hydrochloric ether of tetramethyldia- midotriphenyl carbinol,” a name that ought to excuse almost anything. Coloring and Perfuming. 319 PERFUMING. The odorous substances are incorporated into the body of the soap either by milling- or by crutching- them in just previous to running- the soap into the frame. Many soaps, particularly the low-priced ones for the laundry, are perfumed simply by the incorporation of a single essential oil, so that in their case the perfuming- is an extremely simple mat¬ ter. Some importers of essential oils, as well as manufacturers of perfumery, also make a specialty of furnishing the soap manu¬ facturers ready-made mixtures of essential oils and other aro¬ matic substances, so that in the case of compounded perfumes, also, the soap maker need not necessarily trouble himself about the composition of perfumes. Nevertheless, there are some general rules applying to per¬ fuming soap which the manufacturer can not afford to be un¬ acquainted with, the more so since every soap maker will find it to be of advantage to collect at an early opportunity a good stock of experience in this branch of his business, even if he should find it more convenient for the time being to use only the ready¬ made mixtures. In making up a suitable combination of odor¬ ous substances the price is, of course, of the greatest importance to begin with. But a mixture of high-priced oils may be a very poor perfume, unless they are selected to harmonize with each other. To make up a suitable combination the odor which is to predominate is first selected and then compounded with such ad¬ ditions of other odors in suitable proportion as by experience is found to harmonize therewith. A small variation may mean a great deal practically in this respect. A very pleasant perfume, for instance, is made by Bergamot, 6 parts, Rose geranium 5 Patchouli l}4 “ Santal, 2 Valeria, but, if the /aleria be increased to 2 parts, the mixture will be simply nauseating. Likewise, some oils are simply wasted by adding them to others which overpower them, or which form with them a mix¬ ture of an odor which is represented by some other, much cheaper oil, or quite insipid. Thus musk, which is very expensive, is practically killed by oil of fennel; otto of rose is overpowered Compounding perfume. Wasting oil by in¬ judicious mixing 320 Coloring and Perfuming. by oil of peppermint, etc. Lastly there are two very common sources of failure of even the best of formulas which it is im¬ portant to point out, namely: first , a soap which of itself has a disagreeable odor, and secondly the buying of oils not of the cha¬ racter and odor understood as the true properties of the oil nam¬ ed. A delicate odor is of course worse than wasted when incor¬ porated into a soap of fatty, rancid smell, and a formula cannot be a success when the oil used is not of the same character as that used in the original formula. The substances employed for obtaining the perfumes suit¬ able for soap are of several classes, namely: 1. Vegetable substances , comprising essential oils, balsams, rosins, roots, and bark. The essential oils are by far the most commonly employed ingredients for this purpose; they are sub¬ ject to evaporation and deleterious changes on exposure to the light, air, or heat, as well as to rust in cans, dissolving lead from the latter, &c. They should therefore be kept in a cool, dark place, in glass vessels, and closely stoppered. Ready-mixed perfumes may be kept in a somewhat warmer place, as the elevated temperature accelerates the action of the oils on each other, whereby the perfume “ripens.” 2. Animal substances, which comprise only a very small, but important number of raw materials for perfumery. They are generally used more because they serve excellently for fixing the more volatile vegetable odors than for the sake of their own odor. 3. Artificial products, which are also not as yet very numer¬ ous, and mostly of rather recent origin. Some of these might also be classed with the vegetable substances mentioned above, from which they are extracted by more or less complicated che¬ mical treatment, while others are entirely artificial products. 4. Pomades. The perfumed fat remaining when the princi¬ pal part of their odor has been extracted from the flower pom¬ ades of the perfumer, is used to a limited extent for perfuming soap, by adding this fat to other stock, in the manufacture of soap by the cold process. The following is an alphabetical list of the various substan¬ ces. (The plant from which the oils are derived are named in each case because in regard to some of the oils there is consider¬ able confusion and misunderstanding in the general literature): Allspice Oil, see Pimenta. 321 Coloring and Perfuming. Ambergris, a grayish white secretion of the Cachelot whale. Soluble in alcohol; has a pleasant musk-like odor if properly diluted. Ambrette Seed Oil, distilled from the seed of Abelmoschus Moschatus ; odor resembling musk and civet; Sp. gr. 0.900 to 0.905; contains a free fatty acid which partly separates out at ordinary temperatures. A Copaiba oil mixture has been at times substituted for this oil. Anethol, an artificial product representing the essential constituent of oil of anise and possessing the odor of the latter; colorless. Anise Aldehyde or Aubepine; a colorless liquid resembling in odor the blooming Hawthorn; must be kept in well-stoppered and well-filled bottles, as it oxidizes readily if exposed to the air; agrees well with orange oil and oils of similar odor; readily sol¬ uble in alcohol. Anise Oil; made from the seeds of Pimpinella Anisum\ should be colorless or faintly yellow. Below about 60° F. it solidifies to a white, crystalline mass. (Should not be confounded with oil of Star anise, made of the fruit of Illicium Anisatum .) It must be used sparingly, as its penetrating odor easily overcomes that of other oils used. Sp. gr. 0.980 to 0.990 at 17° C.; optical rotation to the left (very slight); consists chiefly (90%) of ane¬ thol; has been extensively adulterated with the stearopten ob¬ tained from oil of fennel, which, however, can usually be de¬ tected by the change thereby caused in the optical rotation of the oil. Anise oil congeals between 60 and 66° F. Artificial Oil Sassafras is a production closely related to Safrol. Artificial Oil Wintergreen (Methyl Salicylate) is a col¬ orless or yellowish liquid; sp. gr. 1.183 to 187; optically inactive; manufactured on a large scale and used extensively to supplant the Natural Oils of Wintergreen and of Sweet Birch. To test these latter two oils, as well as the artificial (synthetic) oil for adulteration with other volatile oils or with petroleum, add to a measured quantity of the sample in a test tube ten times its vol¬ ume of a 5% solution of pure caustic soda, shake well till a con¬ siderable white precipitate is produced; plug the tube loosely, place in boiling water for five minutes, shaking occasionally; the precipitate should dissolve and form a perfectly clear, almost 322 Coloring and Perfuming. colorless solution, and no oily drops should separate on the sur¬ face nor at the bottom. Aubepine: See Anise Aldehyde. Balsams: See under Copaiba, Peru, Storax, Tolu. Bay Oil. This name is given to two different oils: One, also called “Sweet Bay,” from Laurus Nolnlis , is used in soap to a small extent; the other, also known as “West Indian Bay Oil,” is distilled from the leaves of Myrcia Acris , and used in the man¬ ufacture of bay rum and of soap, especially bath and shaving soaps; the oil of Myrcia is a yellow to brownish-yellow liquid whose odor reminds one of clove oil; sp. gr. 0.970 to 0.990; gives sometimes a clear, sometimes a somewhat turbid solution with 90% alcohol. Benzoin, a gum rosin, with a vanilla-like odor, from the Styrax Benzoin ; collected in a manner similar to that of pine rosin. That from Siam has the finest odor; Sumatra benzoin resembles Styrax somewhat in odor. Bergamot Oil, expressed from the rind of the fruit of Citrus Bergamia. Pale yellow to greenish. Must be carefully kept from the air, as it is very prone to absorb oxygen and become turpen¬ tine-like in odor. It differs from other oils of this family of plants in that it forms a clear solution with caustic potash lye. Sp. gr. 0.882 to 0.886; optical rotation 9 to 15 to the right in a 100 mm. tube. At 70 F. it should give a clear solution with 1)4 to 2 volumes of alcohol of 80% b} T volume; sometimes a pure oil does not answer to this test, in which case, to prove absence of fatty oils, on evaporating a small sample over a water bath until all odor has disappeared, the remaining soft residue should • not exceed six per cent; a greater residue tending to show the proportionate presence of fatty oils. The value of this oil (like that of several other oils) depends principally on one of its constituents, i. e. about 35% to 40% of linaloyl acetate. Its principal adulterants are turpentine, oil of lemon, oil of orange, all of which decrease the specific gravity; the latter is increased by adulteration with fatty oils, cedar-wood oil, gurjun-balsam oil. Birch Oil, also called oil of Sweet Birch, is distilled from the bark of Betula Lenta , Sweet Birch or Black Birch. It is colorless or yellowish, and its odor and taste are very similar to those of wintergreen for which indeed the oil is largely sold. Sp. gr. 1.180 to 1.185; optically inactive; almost a pure methyl salicylate (of Coloring and Perfuming. 323 which the artificial or synthetic oil of wintergreen consists). Has been found adulterated with petroleum, &c. See tests under “Artificial Oil Wintergreen.” Bitter Almond Oil, obtained from Amygdala Amara , the bitter almond, by macerating with water and then distilling, but also made largely from peach and apricot kernels. Colorless or yellowish. Must be kept in air tight container, as on expos¬ ure to air the oil, (especially that freed from prussic acid) will change to a white, odorless, worthless mass (benzoic acid). If oil from a partly used bottle must necessarily be kept on hand, it should either be transferred into a bottle of smaller size so as to exclude the air again on securely corking it, or there should be added to the partly emptied bottle alcohol in the proportion of 10% of the oil still remaining; less than 10% of alcohol, how¬ ever, have no preservative effect whatever. Of course 10% more of this mixture must then be used in the soap, &c., than if the pure oil were used from a fresh bottle. Seealso “Mirbane,” un¬ der Artificial Products. Bitter Almond oil has a sp. gr. of 1.050 to 1.060 and is opti¬ cally inactive; it consists of benzaldehyde (which on exposure to air oxidizes to benzoic acid) and 2 to 4% of hydrocyanic acid, and is therefore highly poisonous, even the oil freed from hydro¬ cyanic acid being* not free from dangerous effects. Oil of higher sp. gr. than named above is likely to contain much more of the poison, as high as 11% having been found in some specimens whose sp. gr. was above 1.090. The artificial oil has been frequently used as an adulterant, and even in some cases to entirely substitute the natural oil. Al¬ cohol and oil of turpentine are also frequent adulterants, but lower the specific gravity. There is as yet no chemical test that will disclose adulteration with pure benzaldehyde. For the detec¬ tion of artificial oil containing chlorinated products the following has been devised by an American firm: A piece of strong, clean cop¬ per wire, with a looped end, is held in a non-luminous flame, such as that of the ordinary Bunsen burner or alcohol lamp, until no color is imparted to the flame, and then permitted to cool. A drop or two of the oil to be tested is then allowed to fall on the looped end of the wire, avoiding any contact of the latter with the fingers, and the oil subsequently ignited and left to burn outside of the flame. The looped end of the wire is now slowly brought in contact with the lower outer edge of the flame. If 324 Coloring and Perfuming. the oil is artificial it will at once impart a distinct but quite tran¬ sient green tinge to the flame, caused by the vapor of the chlor¬ ide of copper formed, while a pure natural oil will produce at the most but a slight yellow color. Cananga Oil. See also under Ylang-Ylang. Sp. gr. 0.915. Soluble in 1 to 2 volumes of 90% alcohol. Often adulterated (with cocoanut oil, &c.) Should remain liquid at freezing- tem¬ perature. Caraway Seed Oil, distilled from seeds of Carurn Carvr, colorless to light yellow; aromatic odor; turns yellow to brown by age. Sp. gr. 0.905 to 0.920. Contains limonene (formerly called carvene) and carvol. Optical rotation 75 to 85- to the right in a 100 mm. tube. Caraway Chaff Oil has a less agreeable odor than that from the seed. Cassia Oil, from the leaves and leaf stems of Cinnamomum Cassia , growing in China. Yellow, gradually becoming dark reddish-brown and thickly fluid. It is similar to, but not as fine, as Cinnamon Oil. As it makes the soap yellowish it should not be used in white soaps. Sp. gr. 1.055 to 1.065. Consists chiefly of cinnamic alde¬ hyde (75 to 88%), on which its value depends chiefly and which should therefore be at least 80%, although oil of this strength is frequently not on the market at all. Has often been found adul¬ terated with rosin, fatty oils, petroleum, cedarwood oil, alcohol, &c. Genuine oil may, however, be as low as 50% in aldehyde, but is then less valuable in proportion than the oil having a high¬ er percentage. A synthetic cassia oil (cinnamic aldehyde) has also been brought upon the market, which is said to be prefer¬ able, among other reasons on account of its lighter color. Cassie Oil. Under this name an oil is brought into commerce which is made from the black currant (Ribes Niger), but the real cassie perfume is from a flower. Acacia Farnesiana , the essential oil of which, however, is not an article of commerce. These oils are not to be confounded with cassia oil. Cedar Wood Oil, distilled from wood of Juniper us Virginia na (largely from the saw dust of lead pencil factories); yellowish to greenish-yellow, thickly fluid; sp. gr. 0.940 to 0.960. Another kind, from the wood of Cedrus Libani, is brownish-yellow and has Coloring and Perfuming. 325 a sp. gr. of 0.985 and a somewhat different odor. Cedar wood oil improves during storage for about a year or two. Cinnamon Oil, from bark of Cinnamomum Zevlanicum . Pale yellow; often adulterated with oil of cassia. Sp. gr. 1.025 to 1.035. Consists chiefly of cinnamic aldehyde and some eugenol. Has been found adulterated with artificial cinnamic aldehyde which, if free from chlorine, is impossible to detect by any means at present known. Citron Oil, from Citrus Mcdica. Very similar to the oil of lemon, which is generally substituted for it. Citronella Oil; one of the grass oils, distilled from the Andropagon Nardu-s , growing in Ceylon and about Singapore; similar in odor to that of the oil of Verbena and of the Indian Lemon Grass Oil, in place of which it is sometimes used. It varies from colorless to a greenish-yellow to a brown color. Sp. gr. 0.895 to 0.915 (Rectified oil as low as 0.890). Fre¬ quently adulterated at its place of manufacture (India) or after¬ wards, with fatty oils or petroleum. To detect these, thoroughly shake a carefully measured sample of the oil with ten times its volume of alcohol of 80 per cent strength (sp. gr. 0.8645); this is best done in corked test tube of convenient size; then let it rest for 12 hours or longer; if neither fatty oils nor petroleum are present, the solution will be clear or at least only slightly opa¬ lescent, and no oil drops will separate from it, neither above nor at the bottom of the test tube. Large amounts of this oil are used in the manufacture of Geraniol. Civet, obtained from an animal related to the cat and found in Africa. It is a soft, smeary, white (later brownish) mass; its odor is somewhat like that of musk and ambergris. Clove Oil, distilled from the unexpanded flowers of Eugenia Aromatica. Colorless and thin when fresh, but soon becomes yel¬ low and thickens on exposure to air. Should not be used in cold- made soap, except in small amounts. Sp. gr. 1.050 to 1.070. Contains 80-90% eugenol. If the oil is free from adulteration with petroleum, oil of turpentine, and fatty oils, it forms a clear solution with double its own volume of a mixture of 2 volumes of alcohol and 1 volume of water. The oil of Clove stems is of a less fine odor. The oil of cloves and of clove-stalks furnish the Eugenol of commerce Copaiba Balsam. A yellowish-brown syrupy liquid, from 326 Coloring and Perfuming. several varities of Copaife?'a. The best is that known as Brazil Balsam, which has an odor not unlike that of santal wood oil. Coumarin is the odorous principle of the tonca bean, just as vanillin is of the vanilla bean, and is manufactured artificially, in the form of crystals both from the bean and also from leaves of a so-called “vanilla plant,” as well as synthetically. It is soluble in water, alcohol, glycerin, ’vaseline, and in oils; used as a fixing agent for the perfumes used in soap and for the purpose of assisting in blending the odors of the various oils, &c. used. Its odor is that of new mown hay and agrees well with lavender, geranium, &c. Has been found on the market adulterated with antifebrin. Dill Oil, distilled from fruit of A net hum Graveolens. Pale yellow, characteristic odor, sp. gr. 0.905 to 0.915. The East Indian dill oil has a markedly different odor. Eucalyptus Oil is distilled from the fresh leaves of Eucaly¬ ptus globulus and a number of other species of Eucalyptus; the oils from these different sources vary more or less from each other in composition, and therefore also in odor, specific gravity, opticial rotation, &c. Those from Eucalyptus globulus, E. oleosa, and some others, have strongly antiseptic properties, owing to more or less cineol (eucalyptol) being contained in them, and are therefore also used medicinally in asthmatic and bronchial affections. Eugenol occupies a similar position to oil of cloves as Saf- rol does to oil of Sassafras; sp. gr. 1.070; gives a clear solution in a 1 or 2% solution of caustic potash. Fennel Oil, distilled from fruit of Foeniculum Vulgare; almost colorless and of a sweetish odor. Sp. gr. 0.960 to 0.975. Con¬ tains about 60% of anethol (which is also the principal constit¬ uent of anise oil) besides pinene, phellandrene, &c. As much oil appears on the market that has been deprived of a portion of of its valuable constituents, it may be observed that a genuine fennel oil solidifies at a temperature of 3 C., owing to the anethol contained in it. Gaultheria, see Wintergreen. Geraniol. A colorless liquid of rose like odor; should give a perfectly clear solution with 15 times its volume of 50% alco¬ hol; must be kept in a cool place, in completely filled, well- stoppered bottles; sp. gr. 0.880 to 0.885. A similar, or possibly chemically identical body is Rhodinol. Coloring and Perfuming. 327 , Geranium Oie, from herb of several species of Pelargonium , as P. Roseum and others; also called Oie of Rose Geranium, and closely resembling- in odor the oil of Rose which is often adulter¬ ated with it. (The names “oil of rose geranium” and i‘Turkish oil of g-eranium” and “East Indian oil of geranium” are some¬ times falsely applied to the oils of gingergrass and of palma- rosa q.v.) Geranium oil appearson the market as “Algerian,” “French,” “Reunion,” and “Spanish,” geranium oils, resembling each other fairly closely in specific gravity (0.886 to 0.898) and opticial ro¬ tation (—7° to —11°); their chief constituent is geraniol, of which the oil contains 80 to 8 5%. If they form a perfectly clear solution with 2 to 3 times their own own volume of 70% alcohol, they are free from adulteration with fatty oils, petroleum and oil of turpentine. The oil is affected by a peculiar odor if it is long kept in tins and should therefore be refilled into glass re¬ ceptacles at the earliest opportunity. Ginger Grass Oil is probably from the same grass from which Palmarosa oil is obtained, but of inferior quality and often heavily adulterated with fatty oils, &c. Guaiacum Wood Oie, distilled from a South American wood of uncertain botanical origin; but probably Bulnesia Sarmienti Eor., of the Argentine Republic. Very thick and viscid, violet¬ like odor; which in soaps resembles the odor of tea, has been sold as “champaca oil” which is not a commercial article at present. Heeiotropin (Piperonal) is a chemical product (in the form of crystals) related to Coumarin and Vanillin, and is much used in soap to imitate the odor of the heliotrope, which it resembles very closely. It is readily soluble in alcohol, glycerin, vaseline, and in essential oils. A slight addition of Coumarin to it improves and strengthens its odor; the oil of petitgrain, lavender, geran¬ ium, lemon, and bergamot and also aubepine harmonise well with it. It must be kept in a cool , dark place, and should be dis¬ solved in alcohol before it is added to the soap to prevent spots. Ionone, made by condensation of citral and acetone and subsequent treatment with dilute sulphuric acid; when properly diluted it has the characteristic odor of violets and may be ad¬ vantageously combined with orris oil; not affected by free alkali. Kuro-moji Oie, distilled from a wood (. Linderci Sericea ) in Japan; balsamic odor; sp. gr. 0.890. Lavender Oie, distilled from flowers of Lavandula Vera . 328 Coloring and Perfuming. Colorless to light yellow; very sensitive to light and air. The true lavender oil must not be mistaken for the oil of Spike Laven¬ der distilled from the herb of Lavandula spica which has a similar but less agreeable odor. The best varieties are the English and the Mount Blanc oils of Lavender, of which, however, each has a distinctive odor. The oil of lavender flowers has a specific gravity of 0.883 to 0.895 and an optical rotation of —5° to —8 in 100 mm. tube; it contains linalool, linaloyl acetate and geraniol, besides a very little cineol (which is much more abundant in oil of spike lavender). It should contain about 35% linalyl acetate* its most valuable constituent, and, to prove its purity, should form a clear solution with 3 volumes of 70% alcohol. The oil of Spike Lavender is much less fragrant than the foregoing, the odor somewhat resembling rosemary, owing to a different com¬ position; sp. gr. 0.905 to 0.920; optical rotation +1 to +9°; it should form a perfectly clear solution with three times its volume of 70% alcohol, if thoroughly shaken and kept in a temperature of 70° F.; if it does not it is probably adulterated with oil of tur¬ pentine or oil of cedarwood. Spike oil is a common adulterant of lavender oil, but manifests its presence by increasing the spe¬ cific gravity of true lavender oil; cedar-wood oil also increases the specific gravity; alcohol and turpentine lower it, so that the simultaneous presence of alcohol and spike lavender oil might counterbalance each other and hence not be indicated by che spe- fic gravity. Lemon OrL, expressed from the fresh peel of the fruit of Citrus Limonum . Pale yellow; loses its odor rapidly on exposure to light and air, being one of the most readily deteriorating es¬ sential oils. Often adulterated with turpentine and acquiring the odor of the latter on exposure to air; should be kept in com¬ pletely full bottles, and preferably in a dark, cool place. Its value depends almost entirely on the constituent “citral.” Sp. gr. *Tliis requirement, it is but fair to say, is one demanded by some aut¬ horities, while others maintain with equal positiveness, that the percentage of linalyl acetate in the finest of oils is much below the amount stated; (which is certainly true of English oils) that the most valuable principles of the oil have not yet been determined; and that the strength of a sample cannot yet be determined by chemical means. Whatever the true solution of the question may be, the nose is in this instance again one of the most reliable guides. Coloring and Perfuming. 329 0.857 to 0.860; optical rotation +60° to +64° in a 100 mm. tube. The examination of specific gravity and of optical rota¬ tion are among-the most reliable tests for this oil, the determina¬ tion of citral being- a complicated process. In the manufacture of “concentrated” oil of lemon terpene is separated from the oil and used ag-ain, on the other hand, to adulterate ordinary oil of lemon; this is a refinement of the former turpentine adulteration for which as yet no reliable test is known. So also is the opti¬ cal rotation no long-er reliable by itself, as adulteration with a mixture of oil of orang-e and oil of turpentine in certain propor¬ tions does not chang-e the optical rotation. Lemon Grass Oil, distilled in the East Indies from Andro - pogon Citratus ; resembles in odor the oils of lemon, citronella, and of verbena, and sometimes called “East Indian oil of Verbena;” sometimes also known as “oil of Melissa,” a name which proper¬ ly belong-s, however, to the oil derived from Melissa Officinalis which has a much finer odor. Yellowish to yellowish brown; sp. gr. 0.895 to 0.905; should form a clear solution with double its volume of 70% alcohol; frequently adulterated, and in turn used to adulterate the oil of verbena; larg-ely used for the manu¬ facture of citral and then sometimes broug-ht upon the market with part of its citral removed. Lilacine. See Terpineol. Lime Oil, expressed from rind of fruit of Citrus Limetta ; sp. gr. 0.880. Oil obtained by distillation has a less agreeable odor. The oil made from the West Indian lime, Citrus Medica , resem¬ bles lemon oil in odor but is strong-er, while the first named va¬ riety has an odor resembling- berg-amot rather than lemon; the sp. gr. of the West Indian oil is 0.880 to 0.885. Linaloe Oil. Distilled by Mexican Indians from a wood (probably that of the white cedar); its odor is somewhat sugges¬ tive of the rose; colorless; sp. gr. 0.875 to 0.885; contains linalool and a little g-eraniol; one part of this oil should g-ive a clear solution with two parts of 70 per cent alcohol. Has been found adulterated with fatty oils. See also Linaool. Linalool: A colorless liquid; sp. gr. 0.880; optical rotation _|—2°; forms a perfectly clear solution with two volumes of 70 per cent alcohol; the essential constituent of oil of linaloe. Mace Oil, distilled from the flesh enveloping- the nutmeg-, Myristica Fragrans, also from the nut itself. Colorless to yellow¬ ish-red. This oil must not be confounded with fatty oil of mace. 330 Coloring and Perfuming. Sp. gr. 0.910 to 0.930; soluble in 3 times its volume of 90 per cent alcohol. Marjoram Oil, Sweet. Distilled from herb of Origanum Majoramr, yellowish or greenish yellow; sp. gr. 0.890 to 0.900. For Wild Marjoram see Origanum. Meeissa Oil, from herb of Melissa Officinalis. Is not used very much, being quite expensive and in fact hardly a com¬ mercial oil. But the name is sometimes used to designate oil of Lemongrass, and the oil is therefore also called “citron- melissa.” Mirbane, also called, “Nitro-Benzole,” “Oil of Mirbane,” “Artifical oil of Bitter Almonds,” and “Essence of Mirbane.” It is made of benzole (a coal tar distillate), by treating it with fuming nitric acid and sulphuric acid. It resembles the oil of Bitter Almonds in odor, but is very poisonous and explo¬ sive, and should therefore not be used for flavoring purposes, and be handled more carefully than is usual. (The name “Arti¬ ficial Oil of Bitter Almonds” is also given to another product, Benzaldehyde, which is also a substitute for the natural oil soaps sometimes unknown to the buyer, and non-poisonous.) Mirbane turns the soap yellow on exposure to light and sun, and such soaps therefore require to be well packed. It is claimed, however, that the best qualities of the oil do not do this. Sp. gr. 1.200. Musk has the most agreeable odor of the animal substances used in perfumery. It is derived from a deer, living on the plat¬ eaus of the Himalayas, which secretes it in a small sack on the hind part of the belly. It occurs in commerce as “musk in pods,” and as “grain musk.” It is used in extremely great dilution for the finest soaps, either for the sake of its own odor or because it serves so well to fix other odors. The grains should have a fatty, shining appearance and brownish black color; if they look dry and dull, a previous extraction of alcohol is to be suspected. It is frequently adulterated with dried blood, partly burnt meat, etc. By burning a small piece in an alcohol flame the odor of burning flesh reveals the latter sophistication. The best musk is that from Tonquin, which is often adulterated, however, by Assam musk which has a weaker odor. The Roentgen rays have been successfully employed for detecting pieces of lead in unopened musk pods, lead being a frequent adulterant of the latter. Myrcia, See Bay Oil. Coloring and Perfuming. 331 Nkroli, See under Orange. Nerofin: Crystals representing 1 the odor of oil Neroli; sol¬ uble in alcohol, fatty oils and essential oils; more lasting in odor than oil Neroli and of about the same strength. Nutmeg Oil, from the fruit of the same plant which also furnishes the oil of Mace which it closely resembles. Colorless or pale yellow; darkening with age; sp. gr. 0.870 to 0.915. Oenanthic Ether, (Artificial Cognac Oil), a colorless, oily liquid, giving a fruity aroma to soaps, especially when used with a little Peru balsam and the oils of cassia and lavender. Oeibanum Oil, distilled from a gum rosin of that name; col¬ orless; balsamic odor; sp. gr. 0.875 to 0.885. Opopanax Oil, distilled from a gum rosin of the same name; greenish-yellow; balsamic odor; sp. gr. 0.860 to 0.900. Easily rosinifies on exposure to air. Orange Oil is of two principal kinds: From the peel of the bitter orange is expressed the oil of Orange Bigaradl; from that of the sweet orange the Oil of Portugal; if simply oil of orange is called for, the oil of bitter orange is generally meant. The oil made from the flowers of the true bitter orange is called Neroli Bigarade; if only the petals of the flowers are used it is called Neroli Petale. The flowers of the sweet orange furnish the oil Neroli Portugal. The oil distilled from the leaves and unripe fruit of the orange tree is called oil Petit Grains. The re¬ marks concerning the keeping of lemon oil apply also to these oils. The oil distilled from the flowers of the bitter orange (oil of Neroli) is yellowish to almost brown; sp. gr. 0.875 to 0.888; op¬ tical rotation-f-5° to-(-10 o in a tube of 100 mm. The oil expressed from the peel of either the bitter or the sweet orange is yellow¬ ish; sp. gr. of both kinds 0.848 to 0.854, and optical rotation-j- 96° to+99° in a 100 mm. tube. The examinations of specific gravity and of optical rotation are, as in the case of lemon oil, the most important tests for orange oils and indeed more reliable for or¬ ange than for lemon oil as it is difficult to find an adulterant for the former that will not effect its rotatory power. Petit Grain oil is less fine than oil neroli; sp. gr. 0.890 to 0.900; soluble in twice its volume of 80 per cent alcohol. Origanum Oil is generally a misnomer for Oil of Thyme. Properly the name belongs to the oil of Wild Marjoram; sp. gr. 0.895. 332 Coloring and Perfuming. Orris Root, from Iridis Florentine; much used for violet soap. (See also remarks on it in the chapter on milled soap.) Orris Root Oil. Distilled from the rhizomes of several species of Iris; solid at ordinary temperatures; violet-like odor. Palmarosa Oil is distilled in India from the grass of a species of Andropogon , but notwithstanding this it is frequently spoken of as “Turkish Geranium Oil” and as “East Indian Geranium Oil.” It is colorless to pale yellowish and of an agreeable odor; sp. gr. 0.890 to 0.900. Soluble, if pure, (like the oil of geranium) in 2 or 3 volumes of 70 per cent alcohol. Frequently adulterat¬ ed with fatty oils. Patchouly Oil, distilled from the leaves of Pogostemon Patchouli yellowish-green to dark brown, ill-smelling till highly diluted; serves as a basis for, and partly to fix, other perfumes, and must be used very sparingly. Sp. gr. 0.970 to 0.990; adult¬ erated with cedarwood oil. This oil improves in quality for several years if stored properly in glass bottles, (not in tins). Pennyroyal Oil, European, (French). This oil is distilled from the herb of Mentha Pulegium and should not be mistaken for the American Oil of Pennyroyal (from Hedeoma pulegioides ) which is different in odor, &c. Yellowish in color; mint-like odor; sp. gr. 0.935 to 0.955; optical rotation in a 100 mm. tube + 18° to +23'. Among the best tests for its purity is its property of giving a clear solution with twice its volume of alcohol of 70 per cent by volume. Peppermint Oil is distilled from the herb of Mentha Piperita; colorless to pale yellowish-green. This oil, from its cooling after¬ effect, is much used—like the oil of wintergreen—for perfum¬ ing tooth soaps and similar preparations. Sp. gr. 0.900 to 0.925. The essential constituent of this oil is menthol, the value of a given sample being ascertained by finding the proportion of men¬ thol present; a fair sample of peppermint contains about 50 per cent of total menthol; the Japanese oil naturally contains about 75 per cent, but its less agreeable taste depreciates its otherwise greater value for such purposes as tooth soaps, &c. The estima¬ tion of the menthol present is so much more important as oils have been on the market from which a part of the menthol had been abstracted. When an American oil which is normal as to men¬ thol contents is thoroughly cooled in a freezing mixture of ice and salt, and a few menthol crystals are then added, the sample soon after congeals to a solid mass; Japanese oil is very frequent- Coloring and Perfuming. 333 ly deprived of its menthol in the manufacture of the latter arti¬ cle; with English oil this is not the case, this oil being more costly than menthol itself. Adulteration by turpentine is detect¬ ed by decreased specific gravity. The principal varieties of this oil are the American, the English, and the Japanese, differing markedly in odor, taste, and physical properties. Peru Balsam, from Toluifera Pereira; used to fix other odors. With a vAnilla or benzoin-like odor. As its odor is changed by the action of lye, it is out of place in a cold-made soap. An oil distilled from it is also used in perfumery. Pimenta Oil, also called Oil of Allspice; distilled from fruit of Pimenta Officinalis. Colorless to pale yellow; odor and composition resembling those of clove oil; sp. gr. 1.045 to 1.055. To show absence of petroleum, turpentine, and fatty oils, one volume of oil of pimenta should form a clear solution with two volumes of a mixture composed of alcohol 2 volumes and water 1 volume. Pine Needle Oil. From the leaves of several species of pine oils are distilled which differ somewhat in odor, &c.; some of these are used to a small extent in perfumery, and more large¬ ly medicinally; a Siberian pine-needle oil is much used for per¬ fuming soaps. Turpentine oil perfumed with acetic acid has been sold for genuine “pine oil.” Rhodinol: See Geraniol. Rhodium, See Rosewood. Rose Geranium, See Geranium. Rose Oil, Attar of Rose, Otto of Rose, are names of the oil derived from several species of roses, Rosa Damascenns , &c. The oil varies from a liquid consistencv to that of butter; yellow or greenish in color; almost solid at about 60 F; sp. gr. 0.860 to 0.875 at 70° F. Said to be rarely unadulterated when it leaves the principal place of production (Bulgaria), the most usual adulteration being geranium, lemongrass and gingergrass oil. When congealed the oil presents scale-like, odorless crystals of stearopten contained in a matrix of a more easily liquefied, frag¬ rant portion called by some rhodinol, but by others geraniol, admixed with a very small portion of some other fragrant sub¬ stances. As yet no reliable tests for the purity of this oil have been discovered, and the odor is still the principal guide in judg¬ ing a sample. Rosemary Oil, from the leaves of Rosmarinus Officinalis. 334 Coloring and Perfuming. Colorless to pale yellow or green; penetrating, somewhat cam¬ phor-like odor. Sp. gr. 0.895 to 0.915. One part of the oil should form a clear solution with ^ to 1^ volumes of alcohol of 90 percent by volume, at 70° F. Optical rotation to the right. Frequently heavily adulterated with oil of turpentine and camphor. Rose Wood Oil; the true oil of this name is not a commer¬ cial article; what is sold as such or as “Oil of Rhodium” is said to be a mixture of rose oil with other essential oils. Rue Oil, distilled from leaves of Rata Graveolens. Yellowish color; sp. gr. 0.834 to 0.840. Often adulterated with alcohol, turpentine, petroleum, &c. Pure oil gives a clear solution with two to three times its volume of alcohol; the presence of turpen¬ tine or petroleum cause a turbid solution. Safrol, is a colorless liquid product obtained by the frac¬ tional distillation of oil of Japanese Camphor, it is an antiseptic and identical with the principal constituent of oil of Sassafras, for which it is now largely substituted in household and cold-made soaps. Sp. gr. 1.100 to 1.108. It is either mixed with the soap, or, in cold-made soap, with the fats before adding lye. It is used either alone or mixed with oil of Citronella, to which a little oil of Cedarwood may be added to make it more lasting. This com¬ position is one of the cheapest perfumes for soap that can be had. Other good combinations are those with Cassia, Lavender, Rosemary, and Spike. Sage Oil, from leaves of Salvia Officinalis ; not unlike pepper¬ mint, but less strong; imparts coolness to the mouth, and is there¬ fore sometimes used for mouth washes. Yellowish to greenish- yellow; sp. gr. 0.915 to 0.925. Santal Wood Oil, distilled from wood of Santalum Album. The wood (an East Indian product) from which this oil is made is frequently called sandal wood, which is a wood, however, that is not fragrant and can be used in perfumery for coloring purposes only. Santal wood oil has a thick, syrup-like consistency and a yellowish color. Copaiba balsam is in some cases substituted for santal oil in soap perfumes, as the odor is very similar and the cost much less. Sp. gr. 0.975 to 0.985. Optical rotation — 17° to—19° in a 100 mm. tube. To test for adulteration with cedar- wood oil, fatty oils, &c., dissolve 1 volume of the oil in 5 volumes of alcohol of 70 per cent by volume; at a temperature of 70° F. East Indian santal wood oil should give a perfectly clear solution. Coloring and Perfuming. 335 West Indian Santal wood oil, however, gives an opaque solution in this test, and so will the former after it has been kept for a time exposed to air and light. Sassafras Oil, distilled from the bark of the root of Sassa¬ fras Officinalis ; yellow to red; much used in ordinary soaps, but now quite extensively substituted for the purpose by “Safrol’’ and by “artificial oil of sassafras,” made from Japan camphor oil. The oil of sassafras has a sp. gr. of 1.070 to 1.0S0, and consists chiefly of safrol and a very little eugenol. Spearmint Oil, distilled from herb of Mentha Viridis ; less fine than oil of Peppermint, but has a somewhat characteristic odor, different from peppermint; refreshing in tooth soaps and dentifrices; colorless to greenish yellow. Sp. gr. 0.925 to 0.960. Spike or Spike Lavender, See Lavender. Star Anise Oil, from the fruit of Illicium Anisatum ; re¬ sembles the oil of anise which is sometimes adulterated with it. Colorless to yellowish; sp. gr. 0.980 to 0.990 at 62° F; congeals at 55 to 64° F.; consists chiefly of anethol which is also the prin¬ cipal constituent of oil of anise. Storax, from Liquidamber Orientalise a balsam, used to fix other odors; from it is distilled the oil of Storax (sp. gr. 0.890 —0.900) which may take the place of the balsam in the prepara¬ tion of perfumes. Tar Oil. Distilled from pine tar; almost colorless when just made, it soon turns reddish-brown; tarry odor; sp. gr. 0.970; used in soaps in place of tar and said to have the same medicinal properties. Beech tar and Birch tar also yield tar oils on dis¬ tillation. Terpineol, is a liquid principle existing in several essen¬ tial oils, and extracted from these and brought into commerce as “Lilacine.” It has the odor of the lilac. Being volatile onlyat a high temperature, it can be used when the soap is comparative¬ ly hot. It is not affected by lye or fatty acids, but its odor and color change unless it is kept well stoppered. Thick, color¬ less, liquid; sp. gr. 0.940; soluble in alcohol, fatty oils, and vase¬ line. Terpineol combines well with such odors as geranium, cananga, and santalwood oil. Thyme Oil, from leaves and flowering tops of Thymus Vul¬ garise (Often misnamed “Oil of Origanum” q. v.) This oil con¬ tains as its principal constituent “thymol,” which is valued as a preservative and said to in a measure prevent soap from turn- 336 Coloring and Perfuimng. ing rancid; thymol is also used in medicated “thymol soap.” Two varieties, the red and the white, areknown. Sp. gr. 0.900 to 0.935, the oil made from dried herb having 1 a sp. gr. approach¬ ing the lower of these figures, while that distilled from fresh herbs being more nearly 0.935. The oil should give a perfectly clear solution with one-half its own volume of alcohol. The Oil of Wild Thyme is distilled from the herb of Thymus Serpyllum and has an odor of both thyme and melissa; sp. gr. 0.915 to 0.920; contains thymol and carvacrol. Thymene, a by-product of Thy¬ mol making, may be used in many cases as a cheap substitute for Thyme oil in soaps. Thyme oil is mostoften adulterated with turpentine. Tolu Balsam, from Toluifera Balsam.um; used to fix other odors; the oil distilled from it (sp. gr. 0.935 to 0.975) has a fine hyacinth-like odor and is also used in perfumes. Vanillin: The odorous constituent of the vanilla bean, is made artificially from the sap of the pines. One ounce of it is calculated to be equal to 40 ounces of the best beans. Soluble in alcohol, water, and glycerin. Sometimes adulterated with acetanilide; the melting point of pure vanillin is 79—82°C. while adulteration with 25 per cent acetanilide lowers it to 62 ; further¬ more pure vanillin is readily and completely soluble in dilute caustic soda lye while the adulterated article is only partly so. Verbena Oil, from Verbena Triphilla Aloysio, Citriodora. has a pleasant, lemon-like odor. It is often adulterated or entirely substituted by oil of lemon grass. Vetiver Oil, from the roots of Andropogon Muricatus; has the property of making the odor of otheroils more lasting. Red¬ dish brown, thickly fluid, of intense, orris-like odor. Sp. gr. 1.015 to 1.025; should be entirely soluble in twice its volume of alcohol of 80 per cent by volume. The oil distilled in the island of Reunion does not give this latter test, has a specific gravity considerably below 1.000, and has a less intense odor. WintergrEEN Oil, from leaves of Giultherii Procumbens (checkerberry) ; much used for soap. Frequently, not to say usually, substituted by birch oil (from Betida Lenta, q. v.) which is very similar. The oil of Wintergreen is much used for similar purposes as the oil of Peppermint. Colorless to yellowish-red; sp. gr. 1.175 to 1.185; optical rotation about —1 in a 100 mm. tube; consists chiefly of methyl salicylate (which is also the “artificial oil of wintergreen”); frequently adulterated with oil Coloring and Perfuming. 337 sassafras, petroleum, &c. See also “Artificial Oil of Winter- green. Ylang-Ylang Oil, from JJnona Odoratissima. One of the finest aromatic substances. (Cananga Oil is a cheaper variety of the same oil. distilled from the flowers of Cananga Odorata, and more frequently used for soaps). Ylang-Ylang oil has a sp. gr. of 0.940 to 0.955; optical rotation—45° to—60° in a 100 mm. tube. Oil of Cananga has a sp. gr. of 0.910 to 0.920. SELECTION AND PREPARATION OF THE PERFUMES. The proper selection of the kind and proportions of aromatic materials to be used for perfuming’ soaps is a special art, and in this respect most soap manufacturers are forced to rely on tried formulas, the preparation of a harmonious compound, from the numerous ingredients, requiring experience and skill. We there¬ fore append a number of such formulas,but will add some special remarks for the guidance in selecting a suitable one. In the first place, in selecting a formula, it should be exam- ined, of course, as to its cost, to see if the price of the soap will fume bear it. Then the composition must be considered, whether it con¬ tains oils that can affect the color of the soap, as in the case of oil of cassia and of cloves for white soap. Then the use of the soap is to be considered; a toilet soap must, of course, never be per¬ fumed to remind the consumer of the smell of laundry soap; tooth soaps are preferably perfumed with oils that have a cool¬ ing after-effect on the mouth, notably peppermint, spearmint, sage, and sometimes wintergreen; shaving soaps must have very little perfume, etc. For perfuming milled soaps the special chapter treating of these gives some specific instructions. For cold-made soap many otherwise good formulas for per¬ fumes are not adapted, as some oils undergo a change when they are in contact with the raw materials while saponification is be¬ ing effected, a number of them being affected deleteriously by the strong lye used in the cold process. The formulas below are given in parts by weight,but in prac¬ tice it will be found more convenient, as a rule, to measure the oils in a graduated glass, instead of weighing them. The weight of a majority of the different oils is sufficiently similar to permit of measuring in this manner without causing bad results. If possible the oils should be mixed a few weeks before they 338 Coloring and Perfuming. Preparing the a re required to give the perfume time to blend into a harmonious perfume. r compound before using. In toilet soaps it is always advisable to use some of the tinc¬ tures, etc., which have been described as serving to make the odor more lasting; as the loss of the latter during the time the soap is in the store would detract from its value, perhaps make it un- salabe, and hurt the trade. These “fixing agents” are especially: The tinctures of Musk, Civet, Ambergris, Benzoin, Tolu, Balsam of Peru, and Storax; also Orris Root (finely powdered, or the tincture). Additions of this kind should not be omitted for the further reason that they permit of some economy in essential oils, a small¬ er quantity of which will have a stronger and more lasting effect than where no such addition is made. The tinctures may be bought ready for use, or can be made by dissolving or extracting the drugs mentioned with alcohol in the following manner: TINCTURE OF MUSK. Musk in grain. 1 oz. Civet. 80 grains. Carbonate of potash. oz. Triturate the ingredients until no more ammoniacal vapors are evolved. Then gradually add two quarts of boiling water, and lastly add 2 quarts of strong alcohol. Bet stand at least a week before using. Or, Musk, in grain. 1 oz. Alcohol. 2 quarts. Granulated sugar. 2 ozs. Potash. 1 oz. Triturate the musk and sugar, gradually adding the alco¬ hol. Let stand as long as possible before using, occasionally stirring. Or , Musk, in grain. 1 oz. Alcohol . 10 ozs. Triturate the musk with the alcohol, using a little ammonia water (about ^ oz.) with it, and shake occasionally for five or six days. After filtering, extract again with only 5 ozs. of alco- Coloring and Perfuming. 339 hoi; repeat a third time and use the weak tincture in place of al¬ cohol the next time. For cheap product, American musk, from the American American musk. Muskrat, is sometimes used, by steeping’it for a few days in warm water, and then adding an equal volume of alcohol. TINCTURE OF CIVET. Civet. 2 ozs. Orris root (ground). 3 ozs. Alcohol . ... 5 quarts. Triturate the civet and orris root, gradually adding the alcohol. Or, Civet. 8 ozs. Oil Lavender. 4 ozs. Alcohol. 5 lbs. Rub the civet and the oil together in a warm mortar, add the alcohol and shake well. Rest, filter and make a second extrac¬ tion as described for tincture of musk. TINCTURE OF AMBERGRIS. Ambergris. 2 ozs. Alcohol. 3 quarts. Treat the same as for civet. The ambergris is made into small pieces with a knife, or may be triturated with some sugar. Let stand, for several weeks at least before using. TINCTURE OF BENZOIN. Benzoin. 1 lb. Alcohol .2 lbs. TINCTURE OF BALSAM OF PERU. Balsam of Peru. 1 lb. Alcohol .. 2 lbs. This tincture has a dark brown color, and a pleasant odor. It should be used only in soaps whose color is not affected by it. TINCTURE OF STORAX. Storax is treated in the same manner as Benzoin and Balsam of Peru. 340 Coloring and Perfuming. TINCTURE OF ORRIS ROOT. Powdered Orris Root. 1 lb. Alcohol.. 10 lbs. This tincture is of value for fixing other odors, but is some¬ times also sold by itself as a cheap violet perfume. Ordinarily orris root is used in soaps in the form of an extremely fine powder. TINCTURE OF TOLU. Balsam of Tolu is treated with alcohol like Benzoin and Balsam of Peru. TINCTURE OF VANILLA. Vanilla. 1 lb. Alcohol. 10 lbs. When exhausted the vanilla is stood aside, exposed to the air, for a time, when the odor will be renewed and may be used by a second extraction. PERFUMES FOR LAUNDRY SOAP. The following are some formulas for the perfuming of laun¬ dry soaps. The quantities are calculated for a frame of about 1,200 lbs. and may, of course, be changed to suit. 1. Oil of Mirbane. 1)4 lbs. 2. Oil of Sassafras. 3. Oil of Mirbane.. Oil of Citronella 4. Oil of Citronella Oil of Mirbane.. 5. Oil of Citronella. 1 lb. Oil of Cloves. y lb. 6. Oil of Mirbane. 1)4 lbs. Oil of Sassafras. >4 lb. 7. Artificial Oil of Sassafras.... 1 lb. Oil of Citronella. 1 lb. (A little oil of Cedarwood may be added, if desired, and will make the odor more lasting.) 1)4 lbs. 1)4 lbs. Va lb. 12 ozs. 4 ozs. Coloring and Perfuming. 341 8. Oil of Lavender. .. 1 lb. Oil of Citronnella. .. 1 lb. 9. Oil of Lavender. .. 1 lb. Oil of Thyme (white). .. 3^ lb. 10. Oil of Lavender. . . 4 parts. Oil of White Thyme. . . 1 part. Oil of Rosemary. .. 2 parts. Oil of Citronella. .. 1^ parts 11. Oil of Caraway. .. 1 lb. Oil of Fennel. .. ^ lb. Oil of Cloves. .. % lb. 12. Oil of French Pennyroyal*.. .. 2 lbs. . Oil of Thyme (white). . . 10 oz. Oil of Lavender flowers. .. 10 oz. Oil of Caraway chaff. .. 5 oz. (For white soap) 13. Oil of French Pennyroyal*. .. 1 lb. Oil of Cassia. .. 1 lb. Oil of Cloves. .. % lb. Oil of Lavender (spike). .. 1 lb (For colored soap) * This oil (0/. Mentha Pidegii ) must not be mistaken for the American Oil of Pennyroyal which is quite different. PERFUMES FOR COLD-HADE SOAPS. As already stated many odors are spoiled by being- introduced into a cold-made soap, but the number of perfume formulas that could be g-iven for these soaps is almost unlimited. The follow¬ ing selection will probably be amply sufficient, however, for all ordinary requirements. The proportion of the compounded per¬ fume to be used in the soap must be left to the discretion of the manufacturer. For laundry soaps by the cold process the fore¬ going “Perfumes for Laundry Soap” may also be used; the fol¬ lowing formulas are more especially for toilet soaps. Oil of Bitter Almond .... .... 4 parts. Oil of Bergamot. ... 1 part. Oil of Bitter Almond.. .. ... 3 parts. Oil of Bergamot. .... 1 part. Oil of Citronella. .... 1 part. (Almond.) 342 Coloring and Perfuming. Artificial Oil of Bitter Al- mond. .22 parts. Oil of Lavender. . . . . 8 parts. (Almond.) Oil of Lavender. . .. . 2 parts. Oil of Bergamot. . . . 2 parts. Oil of Cassia. . 1 part. Tincture of Bciizoe. . 2 parts. Tincture of Balsam of Peru. 1 part. (Violet..) Oil of Lavender .. . .12 parts. Oil of Cassia. .15 parts. Oil of Portugal . . . . . 4 parts. Oil of Caraway. . . . .7 parts. Oil of Geranium . . .2 parts. (Windsor .) Oil of Lavender.. .. . 1 part. Oil of Citronella .. . . 1 part. - Oil of Palmarosa. . ., 1 part. (Rose.) Orris Root, powdered.20 parts. Oil of Bergamot.. . . .15 parts. Oil of Geranium . . . . 7)4 parts Oil of Linaloe. . 9 parts. Tincture of Musk.. . 1 part. (Lily of the Valley) Oil of Citronella.. ., .23 parts Oil of Sassafras. . . . . 8 parts. Oil of Caraway.... . 7 parts. (Honey.) » this may be added, if desired, Oil of Thyme, 12 parts.) Oil of Cassia. .20 parts. Oil of Rosemary . . . .10 parts. Oil of Mirbane.... . 2 parts. (Violet.) (Use in Palm Oil Soap.) Oil of Geranium .. . .20 parts. Oil of Mirbane.... . 3 parts. Oil of Bergamot. . . .10 parts. Oil of Cassia. . 1 part. (Violet.) Oil of Linaloe. .15 parts. Oil of Cananga .. . . . 5 parts. Oil of Palmarosa . . . 2)4 parts. (Lily of the Valley) Coloring and Perfuming. 343 Oil of Bergamot . ... 4 parts. Oil of Lemon . . . . 6 parts. Oil of Portugal . . . . 4 parts. Oil of Lavender . ... 3 parts. Oil of Rosemary. .... 1 parts. (Lau de Cologne.) Oil of Lavender. . . . 1 part. Oil of Caraway. . . . 1 part. Oil of Cassia. ... 1 part. Oil of Thyme . ... 1 part. (Omnibus.) Oil of Citronella . .... 3 parts. Oil of Bergamot . .... 2 parts. Oil of Melissa . . ... 1 part. (Hotie} T .) Oil of Bergamot . . ...18 parts. Oil of Sassafras . . .. 5 parts. Oil of Cloves . parts. Oil of Thyme .. . .. 5 parts. Oil of Neroli . — 2^ parts. (Bouquet.) Oil of Rose . . .. 2 parts. Oil of Geranium . .. . 3 parts. Oil of Cinnamon . . ... 1 part. Oil of Bergamot. .... 2 parts. Oil of Cloves. little. (Rose.) Oil of Caraway. . . ..12 parts. Oil of Bergamot. ....20 parts. Oil of Lavender. . . . 8 parts. Oil of Thyme, white . . .. . ... 7 parts. Oil of Cloves . . . .. 1 part. (Shaving.). Heliotropin . ....20 parts, j parts, i Dissolve in Oil Coumarin . Oil of Petitgrain . ....25 parts. Oil of Gerapium . parts. Oil of Bitter Almond .. .. ....10 parts. (Heliotrope.) Oil of Geranium . . ...10 parts. Oil of Bergamot . . ...10 parts. Tincture of Orris Root . . . . .. . 6 parts. Tincture of Benzoin. ... 6 parts. (Violet.) 344 Coloring and Perfuming. Oil of Bergamot. . 8 parts. Oil of Rose .. . 1 part. Oil of Cloves. . 1 part. Tincture of Musk. .... 1^ parts. Oil of Anise. . 3 parts. Oil of Citronella. . 3 parts. Oil of Lavender. . 2 parts. Oil of Bergamot. . 5 parts. Oil of Cloves. . 1 part. Oil of Thyme. . 3 parts. Oil of Peppermint. . 2 parts. Oil of Caraway . . 4 parts. Oil of Lavender. . 1 j4 parts. (To this may be added, if desired, Oil of Bergamot, 2 parts.) Oil of Verbena. .12 parts. Oil of Bergamot. .12 parts. Oil of Citronella. .10 parts. Oil of Palmarosa. .12 parts. Tincture of Musk. . 1 part. (Honey.) Oil of Thyme. . 3 parts. Oil of Fennel. 9 parts. Oil of Caraway. . 2'A parts. Oil of Lavender. . 2 parts. (Cocoanut Oil of Lavender. . 6 parts. Oil of Caraway. . 4 parts. Oil of Star Anise .... . 3 parts. Oil of Fennel. . 3 parts. (Cocoanut An old-fashioned but very good formula is the following: Powdered Orris Root.5,000 parts. ) Mixed with the Powdered Orange Peel.2,000 parts. ) melted fat. Liquid Storax.1,000 parts.—Dissolved in a lit¬ tle hot fat and strained into the bulk of the latter. Oil Lavender (French) . .. 200 parts. Oil Bergamot. 300 parts. Oil Geranium. 100 parts. Balsam Peru. 50 parts. Added to the soap toward the end of crutching,to¬ gether with the musk. Coloring and Perfuming. 345 Musk. 10 parts. — Rubbed together with some of the lye or a little glycerin. (Violet.) PERFUflES FOR (BOILED) MILLED TOILET SOAPS. The following formulas are from the great number used for incorporation into ready formed soap, whether by milling or re- melting. Some of them no doubt would also give satisfaction for cold-made soap. The following is a very fine fancy odor: Oil of Thyme (white). . 6 parts. Oil of Orange. .. 6 parts. Oil of Bergamot. . 18 parts. Oil of Caraway. . . 9 parts. Oil of Lavender. ..16 parts. Oil of Clove. . . 9 parts. Oil of Cassia. .. 6 parts. Balsam of Peru. .. 6 parts. Oil of Cinnamon. . .20 parts. Oil of Geranium. . . 15 parts. Oil of Valeria. % part. Tincture of Benzoin. ..14 parts. Tincture of Musk . . . 17 parts. (Musk.) Oil of Cassia. .. 3 parts. Oil of Lavender. .. 2 parts. Oil of Caraway. .. 3 parts. (Windsor.) Oil of Orange. .250 parts. Oil of Neroli. .200 parts. Oil of Rose. . 20 parts. (Orange Flower.) (To this may be added, if desired, Musk 1 part.) Oil of Lavender, Montbl. . . . . 5 lbs. Oil of Geranium, rect. on roses 1 lb. Oil of Geranium, African . . . . 3 lbs. Oil of Geranium, Turkish . . . . 1 lb. Oil of Patchouli, Penang. . ... y A ib. Oil of Verbena, French. . .... # ib. Oil of Vetivert, Spanish. Oil of Cloves, Bourbon. . . . . . 1 lb. Oil of Bergamot. .... 2 lbs. Tincture of Musk. . ... 1 lb. Tincture of Ambrette. . .. . ... 1 lb. (White Rose.) 346 Coloring and Perfuming. Oil of Cinnamon. . . ..60 parts. Oil of Cloves. . . .60 parts. Oil of Caraway. . . ..50 parts. Oil of Anise. . . ..30 parts. Oil of Cedarwood ... ....20 parts. Oil of Sassafras. . .15 parts. Oil of Lavender. . . ..15 parts. (Windsor.) Oil of Rose. . . . . 8 parts. Oil of Rose Geranium . . . . . 6 parts. Oil of Cinnamon . . . . . 2 parts. Oil of Berg-amot. . . . . 4 parts. Tincture of Civet. . . . . 2 parts. (Rose.) Oil of Berg-amot. . . . .12 parts. Oil of Lavender. . . .. 8 parts. Oil of Caraway. . . . . 6 parts. Oil of Peppermint. . . .. 3 parts. Oil of Thyme. .... 2 parts. (Elder Flower.) Oil of Lavender. . . 2 parts. Oil of Linaloe. . ... Y\ parts. ( Lily of the Valley) Oil of Lavender. . . .. 6 parts. Oil of Peppermint. . ... 2 parts. Oil of Carawav . . . . . 2 parts. Oil of Lemon. .1 part. Oil of Thvme. j part. Oil of Rosemary. . . .. % part. (Marsh Mallow.) Oil of Lemongrass. ...50 parts. Oil of Citronella. ...200 parts. Oil of Cloves. . .. 30 parts. Oil of Cassia. ..30 parts. (Honey.) Oil of Berg-amot. . ..10 parts. Oil of Geranium . . . . . 2 parts. Oil of Neroli. . . .. 1 part. Oil of Lavender. ... 1 part. Tincture of Civet. . . . . 1 part. Tincture of Musk. . . . . 1 part. Orris Root (powdered) . ....40 parts. (Violet.) Coloring and Perfuming. 347 Heliotropin . .10 parts. Vanillin. .. 2 parts. Musk. part. Balsam Peru. parts. Oil Geranium, Afr. .30 parts. (Heliotrope.) Oil of Thyme . . 2 parts. Oil of Caraway. . 2 parts. Oil of Cassia. . 1 part. Oil of Lavender. . 1 part. ( Elder Flower.) Oil of Bitter Almond. .50 parts. Oil of Bergamot. .20 parts. Oil of Cloves. .10 parts. Oil of Geranium. . 5 parts. Oil of Cedarwood. . 5 parts. Oil of Sassafras. . 5 parts. Tincture of Musk .. .50 parts. Tincture of Tonka beans.. .10 parts. Tincture of Civet . parts. (Almond.) Oil Linaloe. 1 lb. Balsam Peru.. 10 ozs. Bitter Almond. 2 ozs. Tincture Benzoe. 15 ozs. Bergamot. 4 ozs. (Heliotrope.) Oil of Bergamot. 4 parts. Oil of Neroli. 2 parts. Oil of Santalwood . 2 parts. Tincture of Vanilla . 8 parts. Tincture of Civet. 8 parts. (Frangipanni Oil of Bergamot. 8 parts. Oil of Lavender. 4 parts. Oil of Cloves. 2 parts. Oil of Nutmeg. 1 part. Tincture of Musk. 4 parts. (Millefleur). Oil of Linaloe. 5 parts. Oil of Bitter Almond. part. Oil of Cloves. 4 parts. Lilacine. 24 parts. (Shaving.) 348 Coloring and Perfuming. Oil of Citronella. . Oil of Lavender.. . Oil of Caraway. . . Oil of Lavender.. Oil of Rosemary. . Oil of Star Anise 3 parts. 1 part. (Honey.) 3 parts. 2 parts. 2 parts. )4 part. (Honeysuckle.) Oil of Opoponax. 50 parts. Oil of Citronella .250 parts. Oil of Cinnamon (Ceylon).. 15 parts. Oil of Palmarosa.100 parts. Vanillin. 5 parts. Coumarin. 2 parts. Musk. 1 part.* (Opoponax.) *Rubbed together with sugar, or an equivalent in tincture. Oil of Wintergreen. 1 part. Oil of Sassafras. 1 part. Oil of Rose. 6 parts. Oil of Geranium . 25 parts. Oil of Bergamont.100 parts. Oil of Lavender. 20 parts. Oil of Cinnamon. 15 parts. Tincture of Tonka beans. . 50 parts. Tincture of Coumarin. 50 parts. Tincture of Musk. 25 parts. Heliotropin. 5 parts. Oil of Lavender,mont-blanc 4 parts. Oil of Caraway Seeds . 2 parts. Oil of Thyme, red. 1 part. Oil of Rhue. >4 part. Oil of Thyme, white. 2/4 parts. Oil of Lavender,mont-blanc 5 parts. Oil of Caraway Seed. 2)4 parts. Oil of Marjoram. 2 parts. (Tooth Soap.) (New Mown Hay.) (Brown Windsor.) (Guimauve.) Coloring and Perfuming. 349 Oil of Palmarosa. Oil of Lavender Flowers, 2 parts. strong-. 2 parts. Oil of Lavender Spike, flo- wers. 1 part. Oil of Rhue. part. Oil of Anise. % part. Oil of Palommier. 1 part. Oil of Berg-amot. 7 parts. Oil of Palmarosa. 6 parts. Oil of Geranium. 5 parts. Oil of Cedarwood. 2 parts. Oil of Berg-amot. 120 parts. Oil of Orang-e peel. 100 parts. Oil of Lavender. 60 parts. Oil of Palmarosa. 30 parts. Oil of Ging-ergrass. 15 parts. Oil of Cassia.. 25 parts. Oil of Citronella . 25 parts* Oil of Cloves. 15 parts. Oil of Santalwood. 25 parts. Oil of Bitter Almond. 5 parts. Orris root, finely powdered. 100 Musk, rubbed up with milk parts. sug-ar. 1 part. Oil of Lavender. 15 parts. Oil of Neroli.. 30 parts. Oil of Berg-amot. 120 parts. Oil of Geranium (Fr.).... 25 parts. Tincture of musk. 15 parts. Tincture of Civet. 10 parts. (A spicy odor for dark soap.) CHAPTER XVII Pressing the Soap. When the soap, after solidifying- in the frame, has been cut into slabs, bars, and cakes, it requires a period of drying before it is ready to be pressed, the time required for drying varying according to the nature of the soap, and the system of drying employed. (The effect of different methods of drying have been previously explained.) Frequently, in the pressure of business, soap is also pressed without drying properly. Milled soap is ready for the press almost immediately after coming from the plodder. Other toilet soaps, cold-made as well as boiled, should dry at least until each cake is covered with a hardened layer of “skin” on the surface. If this skin is allowed to become too thick, through too long drying, it will cause the cake to crack in pressing; but such soap can be made into ex¬ ceedingly handsome cakes by a simple remedy, namely by cutting off the outer-most solid part of the skin. This process is some¬ times adopted purposely with the object of giving the soap an improved appearance, as well-dried cakes of this kind, from which the hardest part of the skin has been removed by drawing each surface over the knife of an ordinary wood plane, will dry out less afterwards, will have a smoother surface, and will show the de¬ sign of the dies in much sharper outline, than a soap that was simply pressed after drying somewhat. It may here be remark¬ ed that the smooth finish of a soap is improved also by using as thin wire for cutting as possible. Where for any reason the process just described is not suitable —as when it is too expensive, or when the cakes were not cut in size to make allowance for the shaving taken off—the cakes may 352 Pressing the Soap. Pressing twice. be softened by means of warming- them, before pressing-. The latter method is also frequently adopted when the shape of the finished cake is such that the soap cannot easily be cut to corres¬ pond to its outlines, as for example when oval or round cakes are to be pressed from pieces cut square. A special method of preparing- the soap for pressing- consists in exposing- it for a very few moments to the direct action of a current of very hot steam turned upon the cakes. The steam causes a chang-e in the character of the soap on the surface and closes up all its pores; the soap thereby acquires a beautiful fin¬ ish which remains after pressing-,and will be better able to stand exposure to unfavorable weather. The weather prevailing- when soap is pressed is also of some moment, for most soaps sweat on days when the atmosphere is saturated with moisture and are then in poor condition for pressing. On such days the windows of the press-room must be closed to keep out the moisture. A clear, brig-ht day is most favorable for this operation. The cakes are previously cut to conform as nearly as possible to the size and shape of the die, in order not to strain the cohe¬ sion of the particles too much in pressing-, and as said before, this may have to be supported by the warming- of the cakes. Boiled-down soaps and some others, are so short in texture that they cannot be pressed at ail, or at least only into very flat bars, for which reason they are in most cases merely stamped with the necessary letters without pressing the cake itself. To prevent cracking, and to bring out the design of the dies well, it is sometimes necessary to press the soap twice, once in a plain die, which merely shapes the cake, and then in another die bearing the required design. In less extreme cases it is merely necessary to close the dies twice on each cake. The dies themselves must be made in accordance with the grade of the soap to be pressed in them, as has been explained in Chapter V; and the design must be so cut that the soap may withdraw easily from the die, without sticking. Fine lines and sharp corners must be made as strong as possible, and must be adapted to the texture of the soap to be pressed. Brass dies cause brown spots to appear on soap, especially if the latter contains free alkali,which attacks the metal of the dies. Laundry soaps, especially, are therefore better pressed in iron dies. The smoother the dies, the handsomer will be the soaps Pressing the Soap. 353 pressed in them, and some manufacturers use even nickel-plated dies for this reason. A properly dried soap will hardly stick to the dies in press- Lubricating the ing\ if the latter are properly constructed. But frequently soap is pressed in a more or less “green” state, when it becomes nec¬ essary to use some lubricant or other to prevent sticking. Water or glycerin alone are not well adapted for the purpose,but a mix¬ ture of the two gives good results, as does also vaseline. Alcohol or salt water are used similarly, but the latter is not to be recom¬ mended, as it will crystallize on the surface of the soap. Vinegar also is used, but does not act equally well in all soaps. These liquids are applied by simply drawing a sponge, moistened with one or the other of them,across the die after pressing a few cakes, or whenever the soap shows an inclination to stick. At the ends of cakes of soap, especially in milled soap, there is usually seen a mark made by the effect on the grain of the pressing operation. As this is evidently the result of the change of shape which the cake undergoes in the die, a process has been patented of feeding the bar of soap coming from the plodder di¬ rectly to the die, without previously cutting the bar into cakes, so that the die cuts off the required amount of soap. We are not aware of this having been adopted in practice (U. S. Patent No. 461,973). It remains to say a few words about the care of the dies, which in most factories represent quite a little capital: The life of a die depends entirely on the press, and on the care exercised in setting or fastening it to the press, and fre- care of the dies, quent examinations should be made to ascertain the condition of both press and die. As to the press, it is necessary that the slide or part to which the upper die is fastened should move easily, yet steadily, with¬ out shake in its bearings or guides, and this point should be ex¬ amined daily, as pressers have been known to loosen the bolts in order to have easier work, and by this means ruin the die with a few impressions. It is therefore very essential that a press should be so con¬ structed that the guides can be accuratel} 7 adjusted, both at top and at bottom, and securely fastened when this adjustment has been accomplished. To fasten a die in the press, we should suggest to first place the upper die in its place in the slide and merely fasten the cap 354 Pressing the Soap. or set-screw, whichever may be used, with the fingers, to hold it in place; then place the box containing the lower die on the bed¬ plate and carefully lower the slide, so that the upper die will en¬ ter the box without damaging the edges. Holding the slide in this position by keeping the foot on the lever, loosen the cap or set-screw and place the box accurately, so as to place the clamps which fasten the box in the most con¬ venient place, but so that the bolts will not touch the flanges or box to twist or strain the latter when fastened, and fasten the nuts or bolts with the fingers. Now fasten the upper die securely. Before the nuts or bolts holding the box in place are fastened, endeavor to pull or push them in either direction to ascertain their exact position. Should they shift, put them as near as possible in the middle of such motion and again turn down the nut or bolt and continue this un¬ til the play is overcome. Then fasten with a wrench, and care¬ fully move the upper die up and down to see that it enters the box without striking it in the least. You can then press a few bars of soap and again ascertain the accuracy of your work, and also see that the bolts or nuts holding the box are securely fastened. The guide pins now very much used relieve the evil of care¬ less setting very much, } T et great savings in the cost of repairs can be secured by following the foregoing instructions. PART IV. ' . CHAPTER XVIII. Special Soaps. FLOATING SOAP. Floating' soap, as made in this country since a comparatively recent time, is a soap into which air has been forced in the pro¬ cess of crutching, whereby its bulk is enlarg-ed so as to cause it, when hardened, to float on the water. The object of this gen¬ erally is perhaps not so much this property of floating- as the fact that such a soap, when in use, presents a larger surface to the action of the water, and consequently dissolves and washes more rapidly. It is also obvious that any soap in a melted state can be made to float by the simple process of incorporating- air as stated; but ordinarily only a white soap is so treated. Floating- soap may be made by the cold method, but half¬ boiling-, as described on page 2b4, is preferable to it, if indeed the boiling- process is not employed. In fact, a half-boiled soap is sometimes very apt to turn out floating- against the desire of Floating soap by the soap maker. Still another method consists in remelting and ' e "" ltl,,w ' crutching a (white) soap that has been previously dried some¬ what by exposure to the air; this proceeding may be advantage¬ ous for working up scraps, or when the manufacture is not carried out on a sufficiently large scale to warrant making a separate boil. It is self-evident that floating soaps, being of themselves stock for floating more than usually soluble, should be made largely from stock which naturally yields a less soluble soap, such as tallow, and that they should contain less water—rather than more—than ordinary soap. This latter point apparently is not as generally 358 Special Soaps. understood as it should be, to judge from the numerous formulas extant calling for the addition of water to the soap. For the stock, only selected, fresh, white fats and oils are used. Probably no two manufacturers use exactly the same combination, and an equally good soap may be made from vari¬ able proportions of tallow, lard, or lard oil, cotton stearine, and cocoanut oil. Cotton seed oil should be used sparingly, if at all. A good soap results from tallow and 10 to 20 per cent of cocoa- nut oil, with or without the addition of some lard. The addi¬ tion of cocoanut oil in this proportion is desirable from a num¬ ber of points of view, especially, however, because its low solid¬ ifying point permits of air being crutched into it at a compara¬ tively low temperature and because it adds lathering qualities to the soap composed so largely of tallow. Tallow, on the other hand, gives it lasting quality. Rosin is rarely used in a floating soap, and then only of the lightest color. Boiling the soap. The stock must be thoroughly saponified with pure lye and finished in the same manner as described for “White Settled Soap,” Chapter VII., page 205. The soap is allowed to settle and left in the kettle to cool to a temperature between, say, 170 and 180 F., at which it assumes the consistency most favorable „ ... for crutching. It may here be remarked that the exact temper- Crutchmg. ° J * ature most suitable for the purpose depends somewhat on the composition of the stock, and may be ascertained more definitely than stated above in accordance; a pure tallow soap, for instance, would be apt to be too thick for crutching even before it could be made to froth sufficiently. If allowed to cool too far, part of the soap will stick to the sides of some crutchers, and must then be scraped out into the frames and there crutched again to pre¬ vent excessive warping through unevenness of the contents of the frames. If a crutcher is used that automatically scrapes the soap from the sides while working, and cuts up the lumps of soap forming, the necessity of recrutching in the frame on account of this difficulty will of course be avoided. On the other hand, if the soap is crutched while too hot, it will go down again in the frame before cooling, and the lower part will be too heavy to float. When the soap has cooled and thickened sufficiently in the kettle, as stated, crutching is commenced. The exact proceed¬ ing now depends on the style of crutcher used; the machines having a vertical screw are filled with pure soap (no filling be- Special Soaps. 359 ing used for White Floating* soap), so that the cylinder which surrounds the screw still projects above the soap, as the latter must have room to expand. Besides, the air is incorporated more rapidly when the machine is filled in this manner, as the soap falling* over the rim of the center-tube catches the air more readily than if the machine had been filled above the tube. When the Strunz crutcher is employed, a rapid method of oper¬ ating- consists in first filling the machine to only one-half of its capacity, crutching- for about three minutes, and then filling- the machine to within a few inches of the top, when only enough crutching will be required to mix both portions well. In this manner a frame of soap is ready in from 5 to 8 minutes, no mat¬ ter how heavy it naturally is. As the frothy soap in this case does not permit of judging exactly how much soap the crutcher contains, it is weighed into the machine. The exact length of time required for crutching depends on the temperature, the consistency and the proportion of water in the soap, and on the style of machine used for the purpose; the operation is continued until the soap is slightly foamy. It is then run into iron frames, where it cools rapidly, and as it falls somewhat in the center on cooling—the more so the lighter it is x —the edges may be pressed down when the soap begins to harden. For perfuming Oil of Lavender is generally used, but, of course, any other white oil may be employed. The best disposition of the nigre in such a case is a matter depending altogether on careful judgment; it will not usually be safe to use it over on a second batch. If fatty acids (of cottonseed, &c.) are used in the stock, it is quite feasible to use carbonate of soda for saponification of this particular stock. TRANSPARENT SOAP. General Remarks. Transparent soap consists of ordinary soap, to which certain additions have been made for the purpose of rendering it trans¬ parent. Ordinary soap is opaque because of its Crystalline texture, and the process of rendering it transparent by certain admixtures has been aptly compared with the transparency as- . . , , . •, Original process sumed by snow when it is soaked in water. Originally it was made, by dissolving in about one-half its own weight of alcohol, a dry, neutral, boiled soap, and afterwards distilling off again— 360 Special Soaps. Modern Stock. by means of the water bath—the greater part of the alcohol so employed, leaving- the soap behind in an amorphous condition. The soap obtained by this method is unequaled by the transpar¬ ent soap made by any other process, as the soap—to begin with— was most thoroughly saponified, and the fact that it is dissolved in alcohol, permits of settling out at this stage a considerabe amount of impurities which are present in soaps even that have been made of the very finest ingredients; the final product is con¬ sequently more nearly neutral, purer and clearer than a soap to which alcohol has simply been added in small proportions. How¬ ever, this process is now but rarely used, as it is too expensive in comparison with later methods which have been more generally adopted. processes At present, the transparency of a soap is often produced by means of the simple addition of alcohol. In most cases part of the alcohol required for the purpose is substituted by glycer¬ in and sugar or sugar dissolved in water. The sugar so¬ lution causes even greater transparency than does alcohol, and in order to counteract its tendency to soften the soap, sal soda is added in those cases where the alcohol is substituted entirely by glycerin and sugar solution. Transparent soaps made in the latter way— i. c., without alcohol altogether, and hardened b} T sal soda—are very liable to effloresce on keeping. The lowest grade, probably, is that in which boiled starch is used to per¬ form the office of glycerin. Glycerin, although not exactly absolutely necessary, makes the soap clearer and does not evaporate like water and alcohol; for this reason its use is to be recommended, inasmuch as it re¬ duces the required amount of alcohol and sugar water. It is also less expensive than alcohol; but used in too large proportions it causes sweating of the soap. The proportions used of alcohol, glycerin, and sugar solu¬ tion, it will be noticed, are not definitely fixed, but var}- in dif¬ ferent formulas, as will be seen from the examples given here¬ after. By using more or less castor oil in the stock, the required amount of alcohoi is reduced, as this oil forms a naturally more transparent soap; too much of it however, makes the product soft and sticky and also reduces its lathering properties. The stock for transparent soaps may be the same as for the non-transparent toilet soaps, and is generally tallow, with from 25 to 100 per cent cocoanut oil, and more or less castor oil. Stear- 1 Special Soaps. 361 ine is also used quite frequently. Whatever the stock, it must be very carefully purified by lye and alum, in the manner already described, as any impurities remaining- are particularly notice¬ able in transparent soap. Old rancid fats will not make clear transparent soap; the latter would become “flakey.” It is also uselul to remember in this connection that the more cocoanut oil the soap contains, the longer it may be left to cool before framing-, as tallow soap sets at a much higher temperature. The glycerin used for light colored goods must be perfectly colorless, but for the darker soaps this is not necessary, all that is neces¬ sary is that it should be free from lime and of known concentra¬ tion so that the quantity used may be uniform. To prevent cloudiness and spots, care must be taken that all spots from nme. the materials used be free from lime. According to circum¬ stances, lime may occur in the sugar, in the glycerin, and in the water, so that any one of these ingredients may be the cause of cloudiness, through the formation of lime soap. Sugar of a coarse grain is made from thinner solutions than small grained sugar, and therefore less liable to contain lime; that found on the market bearing the mark “Mould A” will very rarely give cause for complaint. Glycerin likewise may contain lime and other salts, in which case the same trouble results. If the presence of lime is sus¬ pected in glycerin, it may be removed by warming the latter slightly, adding 1 lb. of 26° B. sal soda solution to 40 lbs. of glycerin, stirring well and resting. The water used for dissolving the sugar should also be free from lime, and if condensed steam is not at hand for the purpose, the water should be first boiled and treated with soda as just described for glycerin. If the lye contains too much of foreign salts, especially of Lve sal soda, the soap will lose much in transparency on aging, and will effloresce; the lye is therefore best made of the highest grade of caustic, and must of course be clarified by resting, just as has already been described for making lye to be used for the cold process. As to the quantity needed, variations in the stock are such that a formula which gives perfect results at one time, may fail to do so the next time, even with the most exact weigh¬ ing. It is therefore necessary to watch the soap in this respect; when lye is lacking the soap not only is turbid, but may separate in the frame. 362 Special Soaps. The alcohol, especially for light colored soaps, should be free from fusel oil, which turns dark in contact with lye. Care must, of course, also be taken to use the alcohol of uniform strength, or to allow for variations ; the formulas following’ refer to 96 per cent, alcohol. Apart from impure materials, failures in making- transpar¬ ent soap are g-enerally the result of incomplete saponification, of an excess or a lack of strength, or of too small a proportion of liquid in the soap; a certain amount of the latter being required to produce transparency in the first place, even though it may dry out later; on the other hand an excess of water may also be the cause of turbidity. To make a good article, the saponifica¬ tion should be as thorough as possible and the soap be finished neutral before adding the sugar. For this reason half-boiled soaps to which the filling is not added until the soap is uniform¬ ly developed, will always be better than those made by simply crutching the materials together. For light colored soaps the Discoloration by SU g- ar should not be exposed to a high temperature for the furth¬ er reason that it would thereby become colored dark yellow to brown. * For making a batch of transparent soap the stock is either saponified at a temperature of about 120° F.—the alcohol having been mixed with the lye before adding them to the stock, and the filling (sugar, etc.,) being added afterward—or the soap is made by the ordinary process of half-boiling and the alcohol, etc., added at the close of the saponification. The first-men¬ tioned method is the quickest and most economical, but the latter forms a noticeably clearer and lighter-colored product, which is more completely saponified, and will therefore keep longer. Gen¬ erally speaking, larger batches turn out better than small ones, especially as they can be kept at rest for a time when a consider¬ able proportion of impurities settle out. As already stated, the alcohol for transparent soap made by one or the other of these processes is common^ substituted in part by sugar dissolved in water; as the water evaporates and thereby causes the soap to shrink, the smallest necessary amount of it should be used only, and for strictly first-class goods it is omitted altogether—glycerin taking its place. The sugar is dis¬ solved in a little water or in the glycerin by the help of open steam and added to the soap. When the soap is made by mixing the lye and alcohol before saponification, the filling is not Special Soaps. 363 added until a sample of the soap itself remains transparent after it is dropped on a piece of glass and has become cold and set. If the sample shows a milkiness, beginning from the edge , and on pressure of the finger splits up in numerous small, sharp-edged pieces and has more or less cloudy spots distributed over the whole surface, it is a sign that the soap is too strong; a little stock must then be added, for which purpose castor oil is pre¬ ferred, as it is least likely to injure the transparency in case any unsaponified particles should remain. Powdered W. G. Rosin has been similarly employed, but makes the soap softer. But if the sample is milky, feels greasy and soft, and under pressure of the finger merely flattens out instead of breaking up into small pieces, it is a sign that the soap is too weak, and a little lye—diluted with boiling water to about 20° B.—will rem¬ edy the wrong. If the sample on glass shows a fine network of clouds, and on cooling has the appearance just described of a soap that is too strong, and a heavy foam covers the soap in the kettle, more liquid—glycerin or water—is required. The colors for these soaps must be soluble in water or alco¬ hol, insoluble colors destroying the transparency. For further detailson this pointsee the chapter on “Coloring and Perfuming.” In cutting and pressingtransparent soap it should be remem¬ bered that the longer it is left to dry before and after cutting up the frame, the better will it press. Those made without alco¬ hol will increase in transparency after a time. The cakes must be cut as nearly as possible to shape, as the soap will crack if it is attempted to force it in this respect. Oval cakes are for this reason made by running the soap warm into tin tubes, in which it sets and from which it is removed by pushing it out by any convenient contrivance. The tubes conform in shape to that which the cakes are intended to have, and a bar of soap is thus obtained from which the single cakes are cut off. For filling these tubes the soap, after settling, is dipped over into a jacketed kettle, from which it may be drawn off by means of a thin hose or pipe near the bottom. The lower end of the tubes is first plugged by means of hard soap. In drying the cakes care is re¬ quired to prevent over-heating which easily dims the soap. For the purpose of settling out the impurities contained in every soap, it is convenient to use a vessel, which may be sus¬ pended in a water bath (as in water contained in a jacket ket- Cutting and press ing. Moulding. 364 Special Soaps. tie), so that the clear soap may be poured off without mixing with it the precipitated impurities. Following- are a number of representative formulas for vari¬ ous transparent soaps. Crystal Transparent Soap. 140 lbs. Cochin cocoanut oil. 60 “ Stearic acid. 80 “ Glycerin. 99 “ Lye, 39 B. 90 “ Alcohol. Or, 120 lbs. Cocoanut oil. 60 “ Stearin. 60 Glycerin. 60 “ Alcohol. 90 “ Lye, 38 B. Mix the stock and the g-lycerin, heat to 120° F. and saponify by half-boiling-, finishing- the soap neutral. When the stock is well saponified, add the alcohol and raise the heat to 160° F. if the soap then is not neutral, add a few ounces of lye, or of stea¬ ric acid, as required, until the appearance indicates that it is correctly finished—according- to the signs described in the fore¬ going General Remarks. The soap is allowed to rest and cool when it is dipped over into small frames or moulds. If framed too warm it might have a mottled appearance. Glycerin Transparent Soap. 80 lbs. cocoanut oil. 80 “ tallow. 50 “ glycerin. 85 “ alcohol. 80 “ lye, 38° B. The stock and the glycerin are mixed and brought to a tem¬ perature of 120 F., when the alcohol and lye.previously mixed, are run in. When the stock is well saponified, rest for two or three hours and add the color and perfume. The color may be burnt sugar or some aniline color that dissolves clear. If a light colored soap is wanted, half-boil the soap and add the alcohol afterwards. Special Soaps. 365 Transparent Soap with Sugar. 100 lbs. cocoanut oil. 100 “ tallow. 118 “ lye, 35^2° B. 90 “ alcohol. 25 “ glycerin. 40 “ sugar, dissolved in sufficient water to just dissolve it. Or, 44 lbs. cocoanut oil. 44 “ tallow. 26 “ castor oil. 57 “ soda lye 38" B. 40 “ alcohol. 38 “ glycerin. 20 “ sugar, dissolved in 6-lbs. water. Or, 37 lbs. cocoanut oil. 75 “ tallow. 56 “ 38° B. lye. 45 “ qlcohol. 56 “ glycerin. 22 “ sugar, dissolved in 7 lbs. water. The stock is saponified and the soap finished as described under General Remarks. The sugar solution is added when the soap is otherwise finished. After settling and cooling somewhat, perfume and color are added and the soap framed. Transparent Soap with Rosin and Sugar. 100 lbs. tallow. 50 “ cocoanut oil. 50 “ W. G. rosin. 105 “ lye 38° B. 90 “ alcohol. 60 “ sugar, dissolved in 50 lbs. water. Make the soap as previously directed, by half-boiling. Then add the sugar solution and settle for four to five hours. Color and perfume the clear soap in a separate vessel. 366 Special Soaps. Transparent Soap without Alcohol. 40 lbs. cocoanut oil. tallow, castor oil. glycerin, sal soda, soda lye 30° B. sugar, dissolved in 45 lbs. water. 45 50 5 15 81 40 11 4 L 4 4 4 4 4 4 4 4 Or, 48 lbs. tallow. 42 50 85 40 10 16-20 4 4 4 4 4 4 4 4 4 4 4 4 Cochin cocoanut oil. castor oil. lye 35° B. sugar, dissolved in 40 lbs. water, glycerin, sal soda. Make the soap by half-boiling and finish it neutral, as pre¬ viously described. Then add the sugar solution and enough of the sal soda to harden. The solutions should be of about the same temperature as the soap. The sal soda is added in form of a fine powder. Transparent Soap Without Glycerin. 70 lbs. cocoanut oil. 50 20 70 28 54 4 4 4 4 4 4 4 4 4 4 tallow, castor oil. soda lye 38° B. alcohol. sugar, dissolved in 30 lbs. water. Bye and alcohol are crutched into the fats at 190 F., fol¬ lowed closely by the sugar dissolved in the water which has been heated also to 190 F. Then crutch for half an hour longer, color, perfume, and frame. Transparent Soaps Filled with Salts. For filling transparent soap, a solution is made of 6 parts of salt and 5 parts of potash in boiling water; 10 parts sugar are then added, and when all is dissolved enough cold water is used till the solution marks 22° B. while warm. The solution is settled and the clear part drawn off and crutched into the soap at 165° F. Special Soaps. 367 Following’ is a suitable formula: 40 lbs. cocoanut oil. 20 “ stearic acid. 10 “ castor oil. 36 “ lye 38° B. 14 “ glycerin. 20 “ alcohol. 40 “ solution as above. Or, Use any of the following* compositions: cocoanut oil, 26 lbs. 24 lbs. 36 lbs. tallow, 24 “ 27 “ 25 “ castor oil, 10 “ 24 “ 39 “ lye, 32 “ 40 “ 55 “ (36° B.) (38° B.) (36° B.) glycerin, 12 lbs. 12 lbs. sugar, 40 “ 22 >4 “ 20 lbs. water, 30 “ 22 Yi “ 22 “ filling, 30*“ 4^f“ 4J “ alcohol, — 7 % “ 8 “ *Made by dissolving in water to 15° B. equal parts of salt, sal soda, and potash. ■("Consisting of 16° potash solution in which are dissolved also 4 lbs. of sal soda. ^Consisting of sal soda which are dissolved in the water called for by the formula. SHAVING SOAP. V The manufacture of shaving soap has come to be a specialty with certain manufacturers, whose trade in the same is sufficient¬ ly large to warrant them in giving this soap that attention which is required for the production of a high-class article. Although almost any soap may be pressed into service for shaving, there are certain requirements which determine the fitness, and thereby the popularity of any given brand. These requirements may be sum¬ med up as follows: The soap must yield a strong, thick lather— which should soften the hair and remain as long as possible without drying; it must be mild in use, and must keep a long time without turning rancid; in addition an agreeable odor and a nice white color are desirable, and it should be economical in use. Special Soaps. 368 To make a soap of the characteristics mentioned, great care and the best of materials are required. The stock most suitable is clean, hard, fresh beef tallow of the best quality and about 10 to 20 per cent of cocoanut oil. For boiled soap the use of some oleic acid with the tallow also serves the purpose of making a more soluble soap. The lye used is partly potash (say three parts soda lye and one part potash lye). Too large a proportion of cocoanut oil causes the froth to dry up rapidly and fails to render the hair soft enough for shaving; the potash lye causes the soap to ’}ueld a better lather than a pure soda soap, as it produces the froth more rapidly, while a soap made entirely with soda lye yields a poor lather—which is slimy rather than frothy. For the further improvement of the soap, an addition of gum traga- canth is often made, which serves to bind the soap together and also makes it very mild in use, and improves the lathering qual¬ ities. Bassorin, a constituent part of some gums and gum rosins, has been used in the same way. The gum tragacanth is incor¬ porated with some of the hot fat, when the soap is made by the cold process. From 1 to 2 lbs. of the powdered gum to a frame will make a noticeable improvement. It may also be added to the soap by milling it in, as in the manufacture of toilet soaps. Cold-Made Shaving Soap. * It would seem that for making a shaving soap the cold pro¬ cess is less adapted than for any other soap; still, many people are blessed with a skin that is far less sensitive than that of others, and so it happens that cold-made shaving soap also finds some buyers. 400 lbs. tallow. 50 “ cocoanut oil. 200 “ soda lye, 38 B. 25 “ potash lye, 38 B. An improvement results if in this formula the lye is diluted with water to about 35° B. Or, 350 lbs. tallow. 50 < < lard. 100 11 cocoanut oil. 220 11 soda lye, 37^ B. 60 < i potash lye, 32° B. Special Soaps. 369 Or, 300 lbs. tallow. 40 “ cocoanut oil. 150 “ soda lye, 37° B. 24 “ potash lye, 33° B. The stock is melted and strained and allowed to cool to 100° F., when the lye (previously mixed) is added—as more fully de¬ scribed in the chapter on the cold process. The soap is lightly perfumed with a composition somewhat as follows: Oil lavender. .15 parts. “ geranium. .3 “ caraway .. .10 4 4 Oil lavender. .15 parts. “ thyme. .. .10 44 “ caraway. . 8 4 4 “ bergamot . .2 4 4 Oil lavender. . 8 parts. “ sassafras . . 6 4 4 “ citronella. . 4 4 4 If gum tragacanth is to be added, it is previously mixed in some hot fat, taking care to get out all the lumps, and added to the stock in crutching. Of course, enough lye for the additional stock so used must be added. Half-Boiled Shaving Soap. For making shaving soap by half-boiling the above formulas for the cold process may be adopted, using only a slightly high¬ er proportion of lye, as the combination of the materials is more complete. The formula given for a white soap, in the chapter on the half-boiling process, page 262, is also suitable for a shav¬ ing soap. The method of operating has been described in the same place. We append one more formula: 200 lbs. tallow. 40 “ cocoanut oil. 130 “ soda lye 30° B. 25 “ potash lye 30° B. Boiled Shaving Soap. As a soap made’partly with potash cannot be grained with 370 Special Soaps. salt without losing - most of the improvement in its character which is conferred on it by the use of this alkali, it is necessary to proceed somewhat differently than in the ordinary manner of boiling - . The stock, selected as stated before, may be saponified with a mixture of 3 parts soda and 1 part potash lye of about 25° B. until it tastes slightl} 7 sharp, and boiled to evaporate any ex¬ cess of water. Any small excess of strength present is then removed by working - in carefully a small proportion of cocoanut oil. This soap will, of course, contain all the glycerin formed, just like that made by the cold process or by half-boiling. Again, the tallow may be saponified alone with soda lye, grained care¬ fully on salt or strong lye, and settled well. After drawing off the waste lye, the potash lye and then the cocoanut oil are sdded, boiled till thoroughly combined, and either finished as before, or a settled soap is made. A more expensive, though still better product is obtained when the potash lye only is used throughout, the soap obtained by saponifying a fat with potash being changed into hard soda soap of especially fine grain and consistency by the subsequent graining on salt. Antiseptic Shaving Soap. For an antiseptic shaving soap it has been recommended to add 30 lbs. of salol in powder to every 1,000 pounds of soap while the latter is still hot. Salol, one of the most important of modern antiseptics, has been found effective in those species of skin diseases most apt to be transmitted in the act of shaving by barbers. Formerly shaving soap was often milled, but at the present time it is generally either cut square and pressed in round dies, or the round cakes, in which form it is sold, are punched out of the slabs. PERFUMING. Formulas for suitable perfumes for boiled shaving soap may be found in the chapter on “coloring and perfuming.” TOOTH SOAP. For the preservation of the teeth, it is admitted by dentists, nothing is better adapted than the free use of pure soap and a tooth brush. The innumerable preparations on the market, whether liquid, powdered, or in form of a cake, and especially the better ones, nearly always contain soap as the most valuable Special Soaps. 371 ingredient, and whatever else they contain, such as flavoring material, preservatives, etc., are only incidental additions of se¬ condary importance, and sometimes even of only doubtful value. The best means of caring for the teeth are a well-made,neu¬ tral and thoroughly saponified soap, followed by a mouth-wash made by a small quantity of permanganate of potash in water, flavored with peppermint, spearmint, or wintergreen oil. In ad¬ dition to these, the occasional use of some finely powdered sub¬ stance is indicated, and tooth soap therefore is, or should be, the best quality of soap into which has been incorporated more or less of some impalpable and insoluble powder. The latter should preferably consist of precipitated chalk, which is non-gritty, and therefore least apt to damage the enamel of the teeth; next in usefulness is finely powdered pumice stone, which is used by dentists for polishing teeth, but should not be employed too free¬ ly. These two powders may also be employed together using only a very small proportion of pumice stone with a large amount of precipitated chalk. Other substances sometimes used for tooth soap are talc, cuttle fish bone, orris root, sugar (for im¬ proving the taste), glycerin (for soft or liquid preparations), coloring (carmine, cochineal, aniline red), and flavoring oils. Some preparations contain salicjdic acid, but this has been found to be destructive to the teeth; the same may be said of powdered charcoal, cream of tartar, powdered marble dust and other sub¬ stances for which there should be no need in a tooth soap. Pow¬ dered myrrh, however, may be of use for hardening the gums. For an antiseptic tooth soap about 20 grains of thymol may be added to a pound of soap. For flavoring the oils must be selected with reference to their taste; owing to their cooling and preservative effect the oils of peppermint, cloves, wintergreen sassafras and cassia are most commonly used in tooth soaps. The process of manufacture may be varied, but nearly all tooth soap is now made by milling. Many formulas have been pub¬ lished for making it by the cold process, but it is doubtful if any such crude products can really be sold; particularly are those formulas worthless which recommend to add the chalk to the stock before running in the lye, as chalk is but another name for carbonate of lime, whose presence in the unfinished soap causes the formation of lime soap. It is different when the chalk is added to a finished soap as it then produces no further chemical 372 Special Soaps. • action. When other powders are substituted for the chalk the product by the cold process may be slightly better, but it will still be only a crude article, unfit for the purpose at best. Half-boiled or remelted soap are an improvement over the cold process of course, but still not equal to milled soap. We append two formulas. Half-Boiled Tooth Soap. Tallow.35 lbs. Soda Lye 38°.16^ “ Potash l} T e 20°.2^ “ Chalk. 25 “ The stock is strained into the crutcher and saponified at a temperature of 165° F. with the lye which has previously been brought to a temperature of 100 c F; After crutching for about 15 minutes the machine is covered up and saponification sets in during about one hour’s rest. The soap is then crutched very slowly, as more fully described in the chapter on half-boiling, and when it has the appearance of a finished soap the coloring matter and the precipitated chalk are crutched in; lastly the per¬ fume (say 6 parts oil peppermint and 1 of oil of clove) is worked in and the soap framed. Milled Tooth Soap. Neutral soap .•. . . .500 parts. Orris root.200 “ Precipitated chalk.300 “ (Or chalk 250, and Pumice stone or Cuttlefish bone 50 parts.) Glycerin, enough to make the powders into a stiff dough. In order to keep the glycerin in, the cakes of soap are some¬ times brushed over with tincture of benzoin and wrapped in tin foil when dry. For a paste, as sold in tubes, the perfum-ed soap and chalk are mixed with sufficient glycerin to give the desired consistency. SCOURING SOAPS. For cleaning and polishing articles by the simultaneous action of soap and strong friction, as for cleaning knives and forks, kettles, very dirty hands, etc., etc., a considerable number of different soaps are made which all agree in consisting of simple soap and as great an addition of some more or less gritty Special Soaps. 373 powder as the soap will bear. The great variety of these soaps is the result of the numerous different scouring- materials added, selected according- to the use for which the soap is principally intended, and the principal ones of which are: Pumice Stone, Silex, Sand, Tripoli (an earth consisting mainly of silica), Bathbrick, Hornblende Dust, Emery, Kiesel- g-uhr (an infusorial earth), Crocus (a form of ferric oxide), Pre¬ cipitated Chalk, and various clayey deposits found in numerous localities in more or less suitable variety. Asbestos has been recommended for use in soap for glassware, etc. To this list may be further added some special ingredients which enter some soaps for particular purposes, as alum, white lead, etc. As a typ¬ ical example of the manufacture of these soaps we may describe that of Sand Soap. Sand Soap. This soap may be made by the cold process, mixing the sand with the stock; but it is easier to make it by half-boiling, owing to the large quantity of sand added to it. Scraps of soap may also be used for it by remelting. The stock used is preferably cocoanut oil, as it lathers more readily than others, with a large addition of an inert powder, and binds the materials most solidly together. The quantity of sand added may be very high, but for a serviceable article it is best not to exceed, say, 50 per cent to 75 per cent of the weight of soap, which is crutched in as soon as the soap is otherwise ready for framing. In making the soap proper, weak lye of 32° to 35° B. should be used in order that the soap may not be too dry when cutting, and an addition of some mineral soap stock will be a further help to secure a smooth surface. The sand must be very dry when added, or the soap will turn out uneven and crumbly; and while running in the sand slowly the crutching machine should not run too fast, in order to prevent air from being incorporated. As it becomes very hard, it is, of course, necessary to cut it—with thin wire— as soon as cooled. As in all other soaps, the addition of a part potash lye is an improvement, also, in this soap. Perfume may be added if de¬ sired. When other substances than sand are used for these soaps the proceeding may be the same as above, but some manufac¬ turers prefer to let the powder remain in the stock over night, I 374 Special Soaps. and then add the lye next day to this mixture. If it is desired to obtain only the very finest part of any powder, such as of em¬ ery for polishing- metal, etc., this may be done by stirring- it up with water, and drawing- the latter off at once when the heavier particles have settled, and repeating- this once or twice. The powder suspended in the water drawn off is allowed to settle, drained and dried. METAL POLISHING SOAP. There are a number of soap preparations in use for polish¬ ing- metals, some of which answer the purpose admirably. A formula for a good article of this kind is as follows: Soap . 480 lbs. Precipitated chalk. 60 “ White lead . 30 “ Jeweler’s rouge, or cream of tartar. ... 30 “ Magnesia. 30 “ The chalk, magnesia, white lead and cream of tartar must be in the finest powder and intimately mixed with each other, and are added to the soap and well crutched in, in the ordinary manner. HARNESS SOAP. For cleaning, oiling and blackening harness, the necessary ingredients required for the purpose are all combined into one mass, either in the form of hard bar soap, or as a semi-soft mass sold in boxes or jars. A simple hard soap of this kind is made by adding to an unfilled rosin soap sufficient bone black and cod liver, or neats- foot oil, to make a soap of the desired character. No carbonate of soda filling should enter into the composition of such soap. The oil has a preserving influence on the leather, and also main¬ tains the black color better than the ordinary soap. Instead of bone black, which contains phosphate of lime and therefore is apt to cause a grayish color instead of black, there may be used lamp black, Frankfort black, or Berlin blue. For the purpose of making the color adhere to the leather, glycerin, molasses, or a mixture of the two is sometimes added. The following formula furnishes an excellent product: A good settled soap (made of tallow, 10 per cent cocoanut oil and Special Soaps. 375 not over 10 per cent rosin) is mixed with 5 per cent of tar, 10 per cent of neatsfoot oil, and 6 lbs. of lamp black to 1,000 lbs. of soap. Naturally this soap will take a considerable time for drying - . For a soft soap of this kind, some hard soap is mixed with a small proportion of potash soap, say 80 of the former and 20 of the latter, and enoug-h water is added to produce the required consistency. Some unsaponified oil and a little carbonate of am¬ monia are also added. CARBOLIC SOAP. For use in urinals and other purposes, a soap containing carbolic acid is frequently employed. (See also under “Medici¬ nal Soap.” The process for making it is subject to the usual varia¬ tions, but the principal underlying it is simply to make a hard tal¬ low soap (which will dissolve slowly and thus waste less rapidly than others) and adding to it 10 to 15 par cent of carbolic acid. Other disinfectants, especially chloride of zinc, are used in the same manner to neutralize the bad odor of closets, etc. It should be observed that in order to retain its effectiveness, carbolic acid should be added only to soaps containing no free alkali, and although cold-made soap is usually employed for the ordinary grades for coarse use, it would be more to the point to use more thoroughly saponified soap. Owing to the dangerous character of strong carbolic acid, care in handling it should be enjoined upon all who handle it in the factory. RED MOTTLED CASTILE. For 1,000 lbs. of tallow allow 400 lbs. cocoanut oil; run the stock into the kettle, but reserve about 100 lbs. of the cocoanut oil. Also run in a few pails of water and boil; when boiling, run in 8 or 10° lye till paste is formed, gradually increasing the strength of lye to 15 and 20°. Have some strong lye (25-30°) handy to run in if the soap should suddenly thicken from lack of strength. When enough lye has been added the soap will com¬ mence to open and on continuing boiling for 30 or 40 minutes without more lye it must remain open. Finish with a flat grain so that it will drop the lye quickly. Finishing: Draw off the lye and save it for its strength. Then warm up the 100 lbs. of cocoanut oil previously reserved, take out 10 lbs. and mix with it 3 lbs. best English Vermillion and set this coloring mixture 376 Special Soaps. aside. Turn on close steam in soap kettle and slowly feed the cocoanut oil which will take up the strength still in the soap; the latter assumes a pitchy look and, when smooth, the coloring - mix¬ ture is poured over the soap. When scarcely any strength is per¬ ceptible to the taste, no more oil is added, and boiling is contin¬ ued for a few minutes. When the soap no longer slips off the paddle but drops in big flakes and looks smooth and shiny, it is considered done. After 10 minutes rest it is framed and covered up warm to assist the mottle. SALT-WATER SOAP. For use with salt water, as on board of ocean vessels, soap is made entirely of cocoanut oil, as that made from other stock is insoluble in salt water. Such a soap may be made simpty by saponifying cocoanut oil in the ordinary way by the cold process, or it may be made from 150 lbs. cocoanut oil, saponified with about 150 lbs. of 2V lye, and highly filled (after the manner of “Blue Mottled” soaps). TAR SOAP. This was one of the first, if not indeed the first of all medi¬ cated soaps made, it having been observed at an early time that' tar has an excellent effect in chronic skin diseases, being made water-soluble by treatment with.caustic lye or by r incorporation into alkaline soaps. But its popularity is perhaps principally due to the fact that the soap has strong detergent properties, being excellently adapted for use of workmen whose work is such as to make the cleaning of their hands more difficult than usual. A formula for this soap has already been given in the chap¬ ter on “half-boiling.” By the cold process this soap ma}^ be made—but less satis¬ factorily than by half-boiling—by saponifying 50 lbs. tallow and 50 lbs. cocoanut oil with 55 lbs. of 36° lye, and, when the mater¬ ials have joined, adding quickly 8 lbs. or more of tar. The soap must be framed rapidly, as it thickens very soon. The tar, if only little is used, may also be dissolved in the warm stock be¬ fore running in the lye. Formerly coal tar was not infrequently used for soap, but at the present time pine tar, birch tar and juniper tar are in general use, since coal tar dirties the soap dish and towels, has a disa- Special Soaps. 377 greeable odor and has not the healing- influence possessed by wood tar. So far as disinfecting- power is concerned experiments have pretty conclusively demonstrated that pine tar is about twice as effective as is birch tar (which is poorer in the disinfectants kresol, g-uaiacol, &c). Tar oil has been employed instead of tar with g-ood success when the object of the soap is great cleaning- power rather than healing- properties, although it is said that tar oil also has great medicinal properties. The proportion of tar used varies from 5 and 10 to 20, and even as high as 40 lbs. in 100 lbs. of soap. Freshly cut tar soap looks brown, if a comparatively small proportion of it is used; but on aging it turns black, for which reason it is not advisable to add coloring matter too readily, even if a very dark color should be desired. GALL SOAP. Oxgall contains a natural soap whose power to emulsify oils or fats has secured it a reputation as an ingredient for soap in¬ tended for removing dirt from colored fabrics and brightening up faded colors. It is even used pure in dyeing and cleaning es¬ tablishments; but for occasional use in households, for removing spots, it is prepared in combination with soap, as it is impossible to preserve it otherwise. For a soap that is desired to keep well, it is best to prepare the gall by boiling it, and, when cooled to 190° F., stirring in 1 lb. of acetic ether for every 20 lbs. of gall. After resting some time the clarified gall may be drawn off from the sediment; thus prepared it keeps longer and mixes better with the soap. According to the manner in which it is used, it may be added to the soap in the state just explained, or may previous¬ ly be boiled down to half its original weight. There are a great man} 7 different formulas for making this soap, but it would seem that a soap made and sold expressly for the treatment of delicate fabrics and colors ought to be the very best kind of soap, and entirely neutral, so that the only formula to use should be based on a well-boiled and finished soap. Such a formula would be, for instance: Soap.100 lbs. Prepared gall. 8 “ (More or less, as desired.) To this may be added some turpentine, borax, quillaya ex¬ tract, ammonia, benzine, etc., as may seem to suit the trade best. 378 Special Soaps. The last two ingredients mentioned, however, will gradually be lost by evaporation. This soap is generally colored green, it being naturally of a grayish color. MEDICINAL SOAP. A healthy skin depends principally upon a healthy condition of the blood and the capillary blood vessels,' and on a proper nerve tone, coupled with frequent ablutions to maintain the skin in a state of activity regarding all its functions. Washing, be¬ sides simply removing dead epithelial scales, impurities thrown out of the system, and dirt deposited on the skin from the at¬ mosphere or articles touched, also stimulates the skin to proper action through the friction incidental to washing and drying. Soap is therefore one of the requisites for preserving a good com¬ plexion, keeping the skin clean and supplied with only the neces¬ sary oil by removing the excess accumulated, and maintaining due activity of the circulation. Under ordinary circumstances a good toilet soap answers this purpose better than any known substance if used judiciously, for too frequent ablutions or the application of unnecessarily' large amounts of soap are not con¬ ducive to a healthy skin either. The skin of some people seems to be proof against a slight excess of alkali in a soap, but a deli¬ cate skin is very sensitive to it, as carbonated as well as caustic alkali dissolve and remove the fat contained in the outer layers of the skin and leave the latter dry and prone to crack; in ex¬ treme cases an inflamed condition of the skin may even result. When the skin is affected by disease, cleanliness is again one of the essentials for a recovery, for it is readily understood that -just after the disordered surface has been cleansed from all for¬ eign matter it is in the most favorable condition to be acted up¬ on by the topical remedies applied. Soaps in which the medi¬ caments adapted to the particular disease in question are incor¬ porated have long ago been found to be a not inconsiderable aid in treating the latter, for they furnish a, and often the, most convenient mode of application. The mistake should not be made, however, to expect impossibilities of them, and in the ma¬ jority of cases they should be looked upon as valuable aids rather than as positive cures, for in diseases affecting the blood, the blood vessels, or the nervous system, and outwardly showing their affects on the skin, any topical remedy is obviously ineffec¬ tive, except insomuch as it may tend to temporarily check these Special Soaps. 379 visible symptoms. A medicinal soap, properly applied, may be an invaluable aid in combating- a skin eruption arising- from a disordered dig-estive apparatus for instance, but it is not difficult to understand that it can no more effect a cure, when used as the only remedy, than it can cure the disordered stomach. Similarly it is not as g-enerally understood as it should be, that a remedy that is capable of doing g-ood, be it a medicinal soap or any other medicament, is also very likely to be capable of doing- harm if improperly used, and this is indeed true of most medicinal soaps. For this reason the soapmaker should consider himself in line with the drugg-ist rather than with the physician; in other words he should not prepare the true medicinal soaps for indiscriminate sale, but rather direct his energy to the pre¬ paration of soaps to be sold on the recommendation of physicians. It is an undeniable fact that physicians have been for a long time prevented from employing medicinal soaps as much as they otherwise would, for the sole reason that, with a few notable ex¬ ceptions, this class of goods has not been prepared with a due appreciation of what is actually required. Unna and Eichhoff, both widely known dermatologists, have taken great pains to investigate the possibilities of medicated soaps, and it is due largely to their efforts that some very valuable preparations of this kind have been widely introduced. This chapter is, in ac¬ cordance with the foregoing, not intended to contain directions for making a line of soaps to serve as cure-alls, but rather as an explanation of the character of the soaps used by physicians in the treatment of skin diseases. To begin then, the soaps used as vehicles for the numerous medicaments employed are the hard soda soap, the soft potash soap, and liquid soap consisting of potash soap dissolved in suf¬ ficient glycerin to keep it in the liquid state. The last two forms are coming into greater use than they were heretofore, for the reason that hard soap has some unavoidable disadvantages as fol¬ lows: It is very mild in its action (and for that very reason sometimes preferred); it is difficult to preserve without losing most or all of certain volatile or easily decomposed medicaments contained therein, such as carbolic acid and corrosive sublimate; its character is frequently changed by becoming alternately wet and dry. To obviate this it has recently been proposed to add the drugs to powdered soap which can be rapidly made into a soft soap by simply adding water. Each of the three classes of soap 380 Special Soaps. mentioned, hard, soft and liquid, is again divided into neutral, al¬ kaline and superfatted soap, so that there are nine different bases to serve as vehicles for the remedy proper, according* as circumstances require, although for the great majority of cases a neutral soap is preferable. The alkaline soaps are the most strongly effective, while a milder action is obtained from the neutral and the superfatted varieties. A further graduation is obtained by regulating the quantity of soap applied, by the degree of dilution with water, the degree of friction applied, and by the length of time the soap is left in contact with the diseased skin. Of course it is also necessary to have due regard for the properties of the drug to be incorporated, as alkaline soap must naturally not be used in con¬ nection with carbolic acid, for instance, and sublimate can be used only with neutral soap. The manufacture of a neutral hard soap has been described in detail in the preceding pages; this kind is the one most usually employed. To prevent changes in the medicaments introduced, the milling process is undoubtedly the most rational. A neutral potash soap must be made in an indirect manner, as a complete saponification with potash lye can be effected only in the presence of an excess of strength. The first step in its manufacture is to make a hard soda soap from the choicest fat or oil (olive oil) and soda. The fatty acids are next separated from the same b}' the addition of dilute sulphuric acid, and must then be washed out with distilled water until thelatter runsoff per¬ fectly free from any trace of the sulphuric acid. The pure fatty acids are then saponified with pure caustic potash, taking care to finish the soap perfectly neutral. The product is then boiled down to the proper consistency.' The neutral liquid soap is made in the same manner, but diluted to the desired consistency with pure glycerin. Its color approaches that of honey, it is transparent and dissolves clear in water and in alcohol and is of course perfect^ neutral.’ The alkaline liquid soap is made from the foregoing b} T the addition of about 4 per cent of carbonate of potash, and is an excellent detergent for the skin and for medical instruments. It is well adapted for the bath, washing the scalp and wherever scales and crusts are to be removed. The superfatted liquid soap was formerly made by the addi¬ tion of 3 to 4 per cent of olive oil to the neutral soap; but as this Special Soaps. 381 free fat becomes rancid in time, it is now frequently supplanted by the same proportion of lanolin, which keeps indefinitely and besides is more readily absorbed by the skin; the use of super¬ fatted soap was first proposed by Dr. Unna. The superfatted and the alkaline hard and soft soaps are made in like manner from the neutral soaps of their respective type. Superfatted soap, containing- an excess of neutral fat when first made, will not keep very long- at best, and some medica¬ ments have the effect of. spoiling- the soap entirely within a few weeks, so that lanolin or vaseline must in these cases take the place of the excess of oil or fat. It is hardly necessary to point out that, as both lanolin snd vaseline are unsaponifiable, they cannot of course neutralize any excess of alkali present in the soap; all they can do at best is to counteract the effect of such excess, to which action lanolin adds that of increasing-the effects of the medicaments by- reason of the avidity with which the skin absorbs the lanolin. The principal medicinal soaps, which have proved most serviceable in the hands of competent physicians, are the fol¬ lowing - : Soft Soaps: Tar Soap, containing- 1 to 8 drachms of tar to the ounce. Naphthol Soap, containing- fz to 3 drachms (or more) of naphthol to the ounce. Carbolic soap, containing- 10 to 90 grains of carbolic acid to the ounce. Salicylic Soap, containing 10 to 90 grains of calicylic acid to the ounce. Sulphur Soap, containing any desired proportion of sulphur. Balsam of Peru Soap, containing x /z drachm or more to the ounce. Hard Soaps: Alum Soap, containing 10 per cent of alum. Arnica Soap, containing 10 per cent of extract of arnica. Balsam Soap, containing 5 per cent of balsam of Peru. Boro-Glycerin Soap,* containing 10 per cent of a 50 per cent solution of boro-gl} 7 ceride. *Tliis soap is preferred to one simply containing boric acid or borax. 382 Special Soaps. Camphor Soap, containing- 10 per cent of camphor. Carbolic Soap,f containing- 5 per cent of carbolic acid. Chamomile Soap, containing- 10 per cent of extract of cham¬ omile. Ergot Soap, containing 10 per cent extract of ergot. Eucalyptol Soap, containing 5 per cent of oil of eucalyptus. Iodine Soap, containing 3 per cent of resublimed iodine. Naphthol Soap, containing 5 per cent of naphthol. Naphthol-Sulphur Soap, containing 3 per cent of naphthol and 10 per cent of sulphur. Salicyclic Acid Soap, containing 4 per cent salicyclic acid. Sublimate Soap, containing 1 per cent or 2 per cent of cor¬ rosive sublimate. J Sulphur Soap, containing 10 per cent of sulphur. Tar Soap, containing 10 per cent of tar. Tannin Soap, containing 3 per cent to 5 per cent of of tannic acid.§ Tannin-Balsam Soap, containing 2 per cent of tannic acid and 5 per cent of Balsam of Peru. Thymol Soap, containing 3 per cent or crystallized thymol. Witch Hazel Soap, containing 10 per cent of extract of ham- amelis. For their better preservation, medicated hard soaps are usu¬ ally wrapped in parchment paper or foil. Supperfatted Soaps: Aristol Soap, containing 2 per cent of aristol. Benzoic Soap, containing 5 per cent of benzoin. Creolin Soap, containing 5 per cent of creolin. Creosote Soap, containing 2 per cent of creosote. Iodoform Soap, containing 5 per cent of iodoform. Iodol Soap, containing 5 per cent of iodol. Menthol Soap, containing 5 per cent of menthol; used for for the anaesthetic effect on the skin, in pruritus, and in tooth soap; when used on the face the eyes should be fTlie addition of glycerin lessens tlie smell of tlie carbolic acid. Napli- tliol or saliev lie acid soap is often preferred to it on account of the odor. X Corrosive sublimate is decomposed and will discolor the soap, if free alkali is present. ^Tannin soap is recommended for use in cases of excessive sw'eating of hands and feet. Special Soaps. 383 kept well closed, as menthol in contact with the con¬ junction produces a very disagreeable feeliug.of cold. Menthol-Eucalyptol Soap, containing 5 per cent of menthol and 3 per cent of oil of eucalyptus. Pine Needle Oil Soap, containing 10 per cent of pine needle oil. Quinine Soap, containing 5 per cent of quinine. Resorcin Soap, containing 5 per cent of resorcin. Resorcin-Salicylic Soap, containing 5 per cent of resorcin and 3 per cent salicylic acid. Resorcin-Salicylic-Sulphur Soap, containing 5 per cent of rescorin and 3 per cent each of sulphur and salicylic acid. Salol Soap, containing 5 per cent of salol; in use the salol is said to break up into carbolic acid and salicylic acid which then have a stronger action than they usually have. Salicylic-Creosote Soap, containing 5% of salicylic acid and 2% creosote. Sulphur Soap, containing 10%" of sulpur. Sulphur-Salicylic-Tar Soap, containing 5% each of sulphur, salicylic acid and tar. Tar Soap, containing 5% of tar.* Thiol Soap, containing 5% and 10% of thiol. SULPHUR SOAP. Apart from the simple sulphur soap, the manufacture of which by various processes is sufficiently indicated in the pre¬ ceding pages, there may here be mentioned the attempts to bring the sulphur into a more effective form by special means. We refer to the invention patented by J. D. Riedel of Berlin, according to which sulphur is heated for four hours with fatty acids or fats of the so-called unsaturated series (red oil, linseed oil, castor oil) to 250-320° F. whereby a new compound “thiofat” is formed which is then saponified, together with an equal amount of cocoanut oil by lye at a low temperature, (a high temperature would decompose the sulphur compound again). In soap so made - named “thiosapol” the sulphur is chemically bound and presum- *Tar is frequently introduced into soaps which are medicated at the the same time with sulphur, salicylic acid, resorcin, &c. 384 Special Soaps. ably more effective medicinally than can be the sulphur mixed in only mechanically. To carry out this process, the result of which is a soap con¬ taining- 5% of sulphur, 1,000 parts of linseed oil are treated with 166 parts sulphur as stated; of the product 1,000 parts are saponified, tog-ether with 1,000 parts cocoanut oil, at a temper¬ ature of about 75° F., with 1,000 parts soda lye of 35% strength. SURGICAL SOAP. All soap is more or less strongly antiseptic, but in order to increase this quality, various additions are made, of which cor¬ rosive sublimate, carbolic acid, salol, thymol, &c., have already- been mentioned. For surgical use the following is a prescription emanating from a Surgeon (Prof. Reverdin of Geneva): Oil of sweet almond, 72 parts. Caustic potash lye, 12 “ Caustic soda lye, 24 “ Sulpho-carbolate of zinc, 2 “ Oil of rose to perfume. It will be noted that this soap is described as being made by the cold process which, especially with almond oil, is hardly to be recommended from a soap maker’s point of view. However, Dr. Frank L. James of St. Louis states that he has used for years a similar soap, but made with cottonseed oil instead of almond oil and containing more (3%) of sulpho-carbolate of zinc, to his entire satisfaction. The advantages of this soap are that it has remarkable cleansing and antiseptic properties, without being at all iritating to the skin; as the strength of the lye is not given, we will add that the soap is intended to be superfatted. Prof. Reverdin recommends this soap not only for general use in hospital and private practice, but also for washing the hands in dissecting rooms and wherever the hands come in contact with decomposing substances. Further, he urges that barbers should universally adopt its use, and thus protect their customers from various infectious diseases, to which they are exposed in their shops. While it is obviously best to introduce no coloring matter in¬ to soaps to be used for medicinal purposes, they are frequently perfumed, as for instance in the following formula for a Special Soaps. 385 Hipped Camphor Soap. 100 lbs. neutral soap. 3 “ camphor, dissolved in the required quantity of alcohol. Perfumed with Oil of cloves, 4 parts. “ rosemary, 5 “ “ lavender, 10 “ “ peppermint, 3 “ WASHING POWDER. Washing- powders, usually sold to the consumers as soap pow¬ ders, may be described in a g-eneral way as powdered mixtures of soap, with about its own weig-ht—more or less—of carbonate of soda. Some special brands are also made which in addition con¬ tain other deterg-ent ag-ents, such as carbonate of ammonia, sal ammonia, or borax, while still others are found, to which filling in the form of talc, silex, sulphate of soda, paraffin, etc., has been added. The soap itself may have been made by any of the pro¬ cesses known—cold, half-boiled or boiled, settled or boiled down —and the stock used may have been any fat, or mixture of fats, ac¬ cording to the grade of washing-powder to be made. It is thus seen that being either principally or entirely a mixture of soap and soda, these powders have little in common with each other, and the process of their manufacture—and even the machinery used in each case—are equally at variance in the several factor¬ ies, being decided upon independently and improved upon by the soap maker, in accordance with his own peculiar circumstances and experience. It would, therefore, be useless to publish formulas for any one kind of this article, as the stock available, the selling price, the profit intended to be made and the manufacturing facilities are so different that no single formula might suit more than one reader —if any. We will instead describe its manufacture in a manner that will enable the reader to work out his own formula. The average soap powder of the better grade, as stated above, consists of a soap and about a like amount of carbonate of soda, the latter being added either as sal soda or as a mixture of sal soda and soda ash. So far as the soap itself is concerned, the best is again one made by boiling and graining on salt, for, be¬ sides being more perfectly saponified, such a soap has the ad¬ ditional advantage of not containing the glycerin resulting from 386 Special Soaps. the saponification, and therefore remaining - drier when in the form of powder. Furthermore, it islighterin color and purer, owing to the coloring matters and other impurities removed with the waste lye. Rosin is scarcely admissible, or at least not in any consider¬ able proportion, as it would make the product sticky and difficult Making the soap, to reduce to the form of a powder. The stock used, say grease for instance, is saponified in the usual manner with soda lye, and, when it has a slight excess of strength, is grained on salt. The soap is allowed to rest, so as to drop the waste lye thoroughly and to cool off somewhat, and is then ready to be mixed with the soda, etc., unless it is intended to settle it first—as may be done to advantage in the manner described under “Settled Soap. 1 ’ On the other hand, the soap may also be boiled down, so that it will contain comparatively little water, in which case the carbonate of soda to be added may consist of more sal soda and less dry alkali. The mixing may be carried out in a crutcher, in flat boxes on the floor, or in a jacketed kettle (after drawing off the waste lye). If it is done in the kettle it should be one so shaped that the contents can be thoroughly worked by two men provided with hand crutchers and stationed on opposite sides of the kettle. If wooden boxes are used, they should be placed on the floor, of suitable size for mixing, and not more than say 1 Yo. feet deep, to permit thorough crutcliing; into these boxes alternate layers of soap and filling are placed and worked thorough by means of rakes. The easiest manner of working is undoubtedly by the crutching machine. The ingredients to be added, if consisting of several kinds, are best previously mixed with each other, so as to insure uni¬ formity of the mass. Some manufacturers use 50 lbs. of talc, or —which is better—silicate of soda, and 300 lbs. of sal soda to every 300 lbs. of soap in the crutcher, and these are thoroughly worked through, taking care to avoid lumps as much as possible, whereupon the mass is spread on the floor of the drying room and turned over daily by means of rakes, until dry. This process requires nearly a week, and has been superseded in most places by substituting about 100 lbs. of soda ash for the same amount of sal soda in the above mixture, so that the formula would be in this case: Soap.300 lbs. Sal soda, 36°.200—225 lbs. Dry alkali or soda ash. 85—100 lbs. Talc. 50 lbs. Special Soaps. 387 While mixing-, the soap should be kept hot, if possible, by admitting- steam into the jacket, and the sal soda also should be used hot. The effect of the soda ash is to absorb the moisture of the soap, thereby making- the product harder and causing- very quick drying-. The soda ash should be pure, so that the water may not be discolored by it in use. The mixture may be run into frames to set, and afterwards cut into bars and dried. After sufficient drying-, the product is passed through the grinding- mill, sifted and packed. For grinding-, a number of different machines are used, but it is necessary to guard against heating in the mill, to avoid melting of the soap. A simple con-, trivance is a revolving sheet iron drum, perforated in the manner of an ordinary grater, against which the soap is held by any suit¬ able means. The sieve should have suitable attachments for turning the coarse tailings back into the mill. From the above description, the manufacture of a soap pow¬ der by lialf-boiling is self-evident, so we need not go into details regarding it. A variation, however, may be mentioned, which consists in using red oil (oleic acid) as the siock, and saponify¬ ing it by half*boiling, or by the cold process, with caustic lye or a solution of carbonateof soda, using in the firstcase rather less lye than is required for the complete saponification. While the soap is still liquid the soda is added, when, in consequence of the car¬ bonic acid disengaged, the mass rises in a somewhat frothy, dry body, which is soon ready for the mill. Red oil being a fatty acid, it saponifies readily with carbonate of soda, and of course, the product is free from glycerin. In saponifying this stock the precaution, previously mentioned, of adding the red oil to the lye, instead of the reverse, must be observed, in order to prevent bunching of the materials. There is also on the market soap powder containing ammonia in the form of one of its salts (free ammonia would rapidly eva¬ porate). Such powder may have no odor of ammonia while dry, but develops the same rapidly when put into water, especially warm water. Ammonium sulphate used in the proportion of say 5% answers the purpose. If a powder containing this salt and soda ash is dissolved in water, the previously combined ammonia is liberated and shows its presence by its odor and by its deter¬ gent effect, the reaction consisting first in a decomposition of the soap itself with setting free of caustic soda which reacts with the ammonium salt to form sodium sulphate and ammonia, at the 388 Special Soaps. same time the carbonate of soda in the soap powder goes to form sodium sulphate and carbonate of ammonia which has similar de¬ tergent properties as has the gas. Similarly ammonium chlor¬ ide behaves in soap powder, but is more difficult to work with, as unless the powder is dry and free from excess of caustic, it attracts moisture and spoils the packages; in adding this salt to a soap powder a high temperature must be avoided. (See App. Note 19). In concluding it should be repeated that the foregoing has re¬ ference to the better grades of soap powder, as it is not within the province of this book to go into details regarding products which are discreditable to the manufacturer, as an instance of which we will only mention one of a number of formulas which have been highly lauded by parties who ought to know better, as follows: “40 lbs. sal soda, 20 lbs. caustic soda, 15 lbs. sili¬ cate of soda, 2 lbs. palm oil, 20 lbs. water.” Formulas of this kind may be considered valuable by their fortunate possessors, but we do not deem them in any way connected with soap making, nor calculated to serve as a basis for a successful business. An ingenious variation, which is said to be practiced in some European countries, consists in boiling linseeds directly with caustic lye. The product is a thin linseed oil soap contain¬ ing more or less extractive matter which causes strong frothing in use, creating the impression that the amount of soap present is m-uch larger than it really is. CHAPTER XIX. Sal Soda flaking. Owing to the considerable amount of space required in the making of sal soda crystals, and especially to the difficulties of the process in warm localities in which the work can proceed on¬ ly for part of the year, and, lastly, owing to changes which time has wrought in the uses of sal soda, soda ash, washing powders, and kindred products, the making of this product has been dis¬ continued in many factories in which at one time it constituted a considerable part of the business. Notwithstanding, this how¬ ever, there are many readers for whom a description of the pro¬ cess still has a practical interest. The process consists, briefly, of making a saturated or al¬ most saturated hot solution of soda ash in water, with or with¬ out certain additions to be mentioned further on, settling, allow¬ ing to crystallize, and separating the crystals so gained from the mother liquor. To do this work there are required: a tank for dissolving the soda ash and provided with facilities for heating the contents; a number of crystallizing vessels, and an arrangement for drying the crystals obtained; also pipe connections and pumps arranged according to circumstances. For dissolving the soda ash a large tank is needed, preferab¬ ly one arranged with an open steam coil at the bottom, and over¬ hung by a perforated iron basket (sieve) into which the alkali can be thrown so as to be just suspended in the water contained in the tank. A tank of this kind has already been described in the paragraph treating on lye-tanks, and should be provided with the same valves, &c., as there stated. It is almost needless to 390 Sal Soda Making. say that such a tank must be kept ver} 7 clean, especially from rust. The crystallizing- vessels may be of many different sizes, shapes, and materials; they are used in sizes rang-ing- from 200 to 3,500 lbs. capacity, cylindrical, square or cone shaped, of cast iron, wrought iron, sheet iron riveted, enameled or not en¬ ameled, hig-h or rather flat, &c. A convenient shape is 16 x 10 feet and 2 feet deep. The principal difference is in the fact that in a large vessel the crystallization proceeds more slowly, es¬ pecially in warm weather, but yields larg-er and more beautiful crystals. Convenience in the removal of the crystals is another consideration; as to the material of which they are made, the most economical among- those named is as g*ood as any other, if kept properly cleaned, and old tanks of various kinds are some¬ times pressed into service. If of larg-e size, they are best speci¬ ally arrang-ed so as to be easily tilted over, and with walls slant¬ ing-, so that (after previously heating-the walls slightly by steam) the whole contents can be discharged readily by merely tipping the vessel. These vessels are filled nearly to the brim and if they are of large size the crystallization may be hurried by la} 7 - ing across the top a number of iron rods about a foot apart so as to touch the surface of the solution at different points; it is at these points where the first crystals form, whereupon the process spreads rapidly throughout the solution; from these rods smaller ones are sometimes suspended, dipping half-way into the solu¬ tion. As a rusting of the vessels gives a yellowish tint to the crystals, it is necessary to prevent it by not having them empty any longer than can be helped at any time. The Solution. Water: Hard water is preferred for this purpose, as with its use a smaller proportion of sulphate of soda is needed (and much of the latter would retard the crystallization). Soda Ash and additions: A high grade soda ash yields small, soft crystals which moreover retain much of the colored mother liquor; instead of using it pure, therefore, an addition of from 3 to 8 per cent of calcined sodium sulphate (Glauber’s Salt)—more or less according to the water used is hard or soft—is taken ad¬ vantage of in order to obtain beautiful, hard crystals. It is to be remembered, however, that the Glauber’s salt acts chiefly by its mere presence in the solution and does not actuall) 7 enter into Sal Soda Making. 391 the crystals in nearly as large a proportion as it is present in the liquor; on an average the crystals made with its help contain about 2 per cent of Glauber’s salt; the remaining - mother liquor being - so much richer in it, of course, this is a feature to be con¬ sidered also when the latter is used over ag - ain for the next batch. For the purpose of obtaining - clear crystals another addition is made, namely of a very small proportion of chloride of lime. Thus a suitable mixture would be, for a water of average hard¬ ness: 97 per cent soda ash, 2.4 per cent anhydrous sulphate of soda (or correspondingly more if the crystals of Glauber’s salt are used), and 0.1 per cent chloride of lime. Yield : Such a mixture is expected to yield 200 per cent of actual crystals and 60 percent further which remain in the mother liqu¬ or at first and are obtained from it on the next batch. In hot weather, however, a smaller yield may result from one or two causes: for one thing, too much soda may remain in the mother liquor and the loss is then one of working expenses; but on the other hand crystals may form which contain 25 per cent less than their due proportion of water, in which case the crystals turned out are richer in alkali than was intended. (34-37 per cent). (See also Appendix, note 17). Soda ash colored by iron oxide can be used without detri¬ ment, as the iron oxide remains behind in the solution. Making the Solution: Roughly figured, one part of soda ash requires two of water; the solution should be made with hot wa¬ ter, although actual boiling is of no advantage and merely wastes time in clarifying. It is regulated to be an almost saturated solution, indicating 31° Baume while hot, (33° when cold), but in hot weather it requires the strongest solutions (fully 34° B. cold) to crystallize at all. The same method of dissolving, ow¬ ing to the caking properties of soda ash, is followed as described under the preparation of lyes, i. e., the soda ash is placed on a strong wire sieve just immersed in the water. When all is dis¬ solved a rest is allowed for settling, requiring say 10-18 hours during which the solution cools off to 145-165° F.,at which tem¬ perature (no more settling taking place) it is run into the cryst¬ allizing vessels. Instead of settling a filterpress may be used. The sediment in the settling tank is washed for the soda in it, before throwing away. 392 Sal Soda Making. Crystallizing, etc. In the vessels already described, if the weather be cool, com¬ plete crystallization will require about a week—more or less as to size of vessels—but in warm weather it proceeds slowly, re¬ quiring- twice as long- as perhaps as in winter, and even then the yield is smaller, as already pointed out; in very hot climates the manufacture is indeed practically impossible, and in very larg-e plants artificial cooling- has in some instances been resorted to. The completion of the process is recognized by examining the condition of the crystals and measuring the mother liquor with the lye scale; it should indicate 20-22° B. when all the crystals possible or formed. The mother liquor is then removed by suitable means (tipp¬ ing the vessels or pumping), when the crystals will be found firmly adhering to the walls of the vessels and require loosening by the application of heat, which is carried out again according to circumstances, i. e. by hot water, steam, or by main force; for small vessels a hot water bath is sometimes the most conven¬ ient method. After loosening the crystals are drained b} r placing them on a slanting floor and then dried further by either exposing them to the atmosphere or—a much m'ore rapid method—by use of the centrifuge, which dries them almost perfectly. They are then stored in a cool, dry place, protected from draft, so that they will neither attract moisture nor dry out. The remaining mother liquor is used again for the next batch, until finally it becomes so discolored that the crystals be¬ come affected thereby; with the use of chloride of lime and high grade soda ash as described, however, the mother liquor can be used over almost indefinitely by simply collecting it in the tank for making the solution and adding fresh soda ash and water and then proceeding as before. When it gets altogether too dark, requiring an amount of bleach that gives its odor to the pro¬ ducts, it is perhaps possible to use it up for a low grade of soap. It is also convenient to use for keeping the crystallizing vessels filled while they are out of use in hot weather. PART V. - ■ CHAPTER XX. Glycerin and Its Recovery from Waste Lye. In the year 1779 Scheele, a celebrated Swedish chemist of his time, observed that in saponifying olive oil with oxide of lead, the washings contained a sweet substance which he term¬ ed “fat sugar” or “oil-sweet.” The real character of this substance (glycerin) was disclosed by the researches of Chevreul who in 1824 proved fats and oils to be compounds which in the • process of saponification split up into fatty acids and glycerin, absorbing the elements of water in doing so. (See App. Note 2). Since that time the production and utilization of this substance have grown apace. Price’s Patent Candle Company was the first to put on the market a commercially pure glycerin derived from its bye-product in large quantities. Separated and purified, glycerin has gained an immense field of usefulness in the comparatively short time since its discovery. Its employment in soap itself has already been sufficiently set forth; in the manufacture of various cosmetics and in pharmacy it finds a still more extensive use; enormous quantities find an outlet in the manufacture of nitro-glycerin and dynamite, and finally its high boiling point, affinity for water, solvent power, and its other properties, have secured it a field of great useful¬ ness in various industries. Thus in the textile industry large quantities are needed to give suppleness to the thread or to the goods in various stages of their manufacture its great advant¬ age for this purpose lying in the fact that simple water readily removes the glycerin again when it is no longer needed. In the fur and leather industries it finds somewhat similar employment. In liquid glues, hektograph compositions, printers’ rollers, print- 396 Glycerin and Its Recovery from Waste Lye. ing and copying- inks, colors, certain kinds of paper, and a great many other articles, it finds useful employment. As a result of these many uses, glycerin has a market value which has made the recovery from waste lye remunerative, and whereas formerly waste lye was universally run away—the glycerin needed being obtained nearly altogether from candle factories—it is now a very general practice in the large soap factories to work up the waste lye for its glycerin. There are, accordingly, these two great sources of the gly¬ cerin of commerce at the present time: 1. Waste lye of the soap factory; 2. From candle factories, as by-product in the manu¬ facture of fatty acids from fats and oils for candle making; this production of fatty acids for candles is done in various ways which fall into two large groups,namely a) subjection of the fat to 9 to 10 atmospheres of steam pressure in a closed vessel (with or without a few per cent of lime or magnesia being added to the fat), or b) adding concentrated sulphuric acid to the fat heating with water, and distilling off the fatty acids in a current of super¬ heated steam; in the latter process of “acid saponification” or “distillation,” the glycerin (which is contained in the “sweet water” which also comes over but separates from the fatty acids) is less pure than when the saponification is carried out by simple steam and pressure. The glycerin from all these sources is further purified by various means adapted to the nature of the crude product obtain¬ ed, so that there are the following chief divisions: A. Crude: 1) From soapmakcrs ’ lye; the least pure, generally speaking. 2) Saponified , (from fats treated with steam under pres¬ sure); the purest, generally speaking. 3) From distillation , i. e. obtained from fat by acid saponi¬ fication and subsequent distilling; in quality inter¬ mediate between the foregoing two. B. Purified: 1) Refined , still containing chlorides, sulphates, &c., but sufficiently pure for most purposes. 2) Dynamite glycerin: distilled, but not chemically pure, still containing traces of chlorine and various empy- reumatic substances. 3) Distilled, chemically pure, for use in medicines, &c. Glycerin and Its Recovery from Waste Lye. 397 The amount of glycerin theoretically yielded by different fats and oils ranges from 9.13% castor oil to 10% for tallow and 12.11% for cocoanut oil; but the full amount is never recovered in actual practice. The different percentage depends on the dif¬ ferent combining value of stearin, olein, palmitin, myristin, etc. In a series of tests made of cases in actual practice in a French factory there were recovered the following amounts of crude glycerin: From Olive Oil, 7-9% Peanut Oil, 6-7% Cotton “ 7—9% Palm “ 5-10% Palmkernel Oil, 6—10% ! Cocoanut “ 7-8% Tallow “ 9—10% The crude glycerin in question contained about 80% of the pure article, some of which however is lost in recovering it. When pure glycerin is a water white, very viscid fluid, sp. gr. 1.266; so that commercial glycerin usually has a sp. gr. of about 1.260 to 1.264 it has a sweet taste and rapidly absorbs moisture from the atmosphere; it is soluble in alcohol, but only very slightly soluble in ether and insoluble in chloroform and benzine; chemically it belongs to the group of alcohols. Strictly speaking it is not present ready-formed in neutral fats and oils; what is present in these is “glyceryl” which, during saponifica¬ tion, absorbs oxygen and hydrogen and becomes glycerin. Ow¬ ing to its power of dissolving considerable amounts of salts and organic impurities its purification is a somewhatdifficult problem. RECOVERY FROM WASTE LYE. When neutral fats have been boiled with lye and the fatty acids have combined with the alkali, and the soap has been grained with salt or lye, glycerin is found dissolved in the waste lye. Of course no glycerin could be obtained from treating fatty acids (e.g. red oil, rosin) with lye, and the lye from the first change alone con¬ tains considerable amounts of the glycerin resulting from treat¬ ing neutral fats with lye. What glycerin is not taken out in this lye finds its way mostly into the strengthening lye, and (as this is saved for the next batch;, is recovered after the strengthening lye has been used over to kill stock for the next batch. A waste lye contains therefore chiefly water with very vari¬ able amounts, according to circumstances, of glycerin, caustic, 398 ' Glycerin and Its Recovery from Waste Lye. carbonate, salt, soap, glue, and other impurities of animal or vegetable origin. As these variations effect the success of re¬ covering the glycerin, both as to cost and quality,they require con¬ sideration as early as the first change of soapmaking. The weaker the lye, the more thoroughly will it extract the glycerin, which more than offsets the greater amount of water to be eva¬ porated. Another early consideration is the graining of the soap at the end of the first change: one may grain with salt and directly work up the waste lye which on an average will contain about b% glycerin and say 9 % of salt, or the soap at the end of the first change may be grained with lye and the waste lye used for another batch, and so on till the lye is heavily charged with glycerin; by then graining with salt a waste lye is obtained which not only requires a minimum of evaporation for a given amount of glycerin, but also gives the least possible amount of salt precipitating during the evaporation. To what extent these considerations can be used to advantage will depend largely on the quality of the stock used. Again, after graining, an extra pickle change may be given in order to more thoroughly wash out the glycerin; whether or not this will pay depends on the facilities for evaporating the excessive water economically and on the more or less advantageous disposal of the additional gly¬ cerin so recovered. In its main features the process for crude glycerin recovery consists, first of a preliminary cleaning, then evaporating a con¬ siderable portion of the water whereby a large portion of the salts is thrown out of solution by reason of the concentration; this salt is removed and an acid is added to the lye for the purpose of de¬ composing remnants of soap and precipitating with it incidentally some of the other impurities; after taking off this precipitate of fatty acids, &c., the lye can be still further boiled down and some more salt removed. When a specific gravity of about 1.3 is reached a crude glycerin is the result. This is purified further by distil¬ lation, etc. From this general principle, which was the basis of the first attempts at glycerin recovery, a number of variations have in the course of time been devised, having in view the re¬ moval of certain other (chiefly organic) impurities present in waste lyes of varying origin and character; these variations em¬ brace chiefly filtration, addition of chemicals adapted to the removal of special impurities, and mechanical appliances, for economical evaporation, removal of salt, &c., not to speak of a Glycerin and Its Recovery from Waste Lye. 399 patent for purifying- the lye by electricity, these inventions have grown out, by proper selection and combination of suitable fea¬ tures, a system of glycerin recovery that has found very extensive use and which has made it possible at the present time to make from waste lye the chemically pure article answering the strictest requirements of the pharmacopia, whereas only a few years ago it was not possible to do better than to make the dynamite grade of glycerin from waste lye. In the course of the line of treatment so briefly indicated just now, which waste lye must undergo, there arise some prac¬ tical problems and difficulties whose solution in the most practi¬ cal manner will probably always determine the precise methods of glycerin recovery that will survive. Thus on boiling down the lye, the increasing concentration involves also the impurities present, and at the same time the more concentrated glycerin has a greater solvent power, so that previously suspended im¬ purities now become actually dissolved and the glycerin corres¬ pondingly more impure. The removal of impurities in the early steps of the process is therefore one of the great desiderata. At the same time each particular means adopted for this early re¬ moval brings its own problems. Then again, as the lye is more and more concentrated, an increasing amount of salt is precipit¬ ated and this must be disposed of in such a way that it cannot interfere with the heating surface of the apparatus and thereby interrupt the work. Chemicals used for precipitating impurities must be of a nature to either deposit before concentration, or if they remain they must be incapable on concentration to do any harm (as for instance sulphuric acid would carbonize certain im¬ purities on becoming concentrated, &c.) Owing to the manipulations necessary for the rational treat¬ ment of lyes, before a pure glycerin is obtained, it is only the larg-e soap factories that carry out the entire process, smaller factories which have only a limited amount of lye to work up limiting their work to the production of crude glycerin or even to simply concentrating their lye for the saving of freight on the water removed by evaporation, and shipping their product to the refinery. The process then is divisible into the two main divi¬ sions: making crude glycerin from waste lye, and making puri¬ fied or distilled glycerin from the crude. Coming now to the details of the process, attention is first directed to the means for removing alkali, albuminous and rosin- 400 Glycerin and Its Recovery from Waste Lye. ous impurities and remnants of soap. Hagemann for this pur¬ pose added first lime and then resin to neutralize the caustic and the lye is then concentrated by boiling-; then hydrochloric acid was added, and next ferric chloride to precipitate cyanog-en com¬ pounds; then followed the forcing of air through the liquid and a treatment with clay or alumina, neutralization with soda, and then the lye was ready for evaporation. This process, with various modifications, was extensively used until it was sup¬ planted by treatment with persulphate of iron which results in formation of ferric hydrate and iron soaps; the latter, in preci¬ pitating, act as clarifying agent and remove considerable al¬ buminous and coloring matters. Some free acid contained in the sulphate, and some acid added besides, neutralize the lye, from which the precipitate mentioned is then removed by a filter press. The filtrate from the filter press is now to be concentrated by evaporation. For this purpose vacuum tanks are used, arranged with a view to economize in the use of steam and to facilities for keeping the heating apparatus clear of depositing salt; as the lye becomes heavier by evaporation of the water, more and more salt (sodium chloride and sulphate) is gradually separated and removed. The salt is washed to free it from the glycerin and then dried to be used over again for graining soap. In this manner is obtained at last a crude glycerin which con¬ tains about 80 per cent of glycerin, 6 per cent of salt, 5 per cent organic impurities, and 10 per cent of water. The crude glycerin is then subjected, at home or in a separ¬ ate refinery, to the process of distillation. According to the figures furnished by a refiner, the best crude obtained from waste lye yields about 72 to 74 per cent pure glycerin. (The crude glycerin obtained in the stearine industry by saponifica¬ tion with steam under pressure yields 82 to 90 per cent). Insomuch as the substance of these proceedings is pretty ex¬ tensively covered with patents, both as to processes and mach¬ inery, it seems advisable to proceed now by referring to the fol¬ lowing extracts from the patent records: As early as September, 1870, a patent was granted in this country (to B. T. Babbitt) for the treatment of sub-lye for the recovery of glycerin; there followed patents granted to J. P. Battershall (1882) and to C. V. Clolus (1883) and notably those granted Oct. 4, 1887, and June 26, 1888, to A. Domeier and O. C. Glycerin and Its Recovery from Waste Lye. 401 Hagemann. The latter patents fairly covered the first processes that were really adopted in practice to any extent, i.e., the soapy matters are precipitated in the form of insoluble soaps, by means of caustic lime, baryte or other metallic oxide, the lye then con¬ centrated by boiling’, the still remaining’ fatty and resinous mat¬ ters decomposed by means of hydrochloric acid or sulphuric acid and removed with kaolin, alum;, or the like; albuminous matters still present are removed by boiling’ with soda and the crude gdycerin thus obtained distilled and refined in the ordinary way. Next followed a patent to E. K. Mitting-, dated July 3, 1888, covering- the removal of fatty and resinous impurities by preci¬ pitation with chloride of barium or strontium and subsequent addition of sulphuric acid; the salt recovered from the spent lye is purified by a series of washing’s to remove the gdycerin occluded by the salt. An apparatus and process for separating- the salt from the boiling- gdycerin liquor was the subject of the next pat¬ ent granted to Domeier and Hagemann on May 20, 1890. About the same time (Feb. 25, 1890) E. D. Mellen patented the pro¬ cess of treating- waste lye (obtained by graining- the soap with excess of alkali) by means of carbonic acid, thereby converting the alkali into a bicarbonate which is insoluble in glycerin. Where caustic lime is used to precipitate insoluble soaps, the fatty acids are—according to a* patent granted E. K. Mitting, May 20, 1890—recovered by treatment with acid, such as hydro¬ chloric, which results in soluble chloride of the metal and free fatty acid which is removed; the soluble chloride is treated with caustic soda which precipitates the hydroxide of the original metal, and the sodium chloride formed is recovered in the subse¬ quent evaporation. Coming now to more recent times we quote the following patents: Patent dated June 9, 1891, granted to Albert Domeier and O. C. Hagemann: The lye, if it contains alkali worth saving, may be first treated according to the previously mentioned pat¬ ent of July 26, 1888. Then any free alkali is neutralized by some suitable aid; next a metallic oxide or hydroxide—such as that of iron or ba^ta—is added to form insoluble metallic soaps; acid may now be added from time to time to neutralize the alkali set free by the oxide; mechanical stirrers or a current of air are used to agitate and heating to 70 or 80° C. may be employed in addition. The precipitate, chiefly metallic soaps and albumin- 402 Glycerin and Its Recovery from Waste Lye. ous matter, is removed by decanting’or filtration. Concentration by boiling’ to a temperature of 150° C. yields a crude glycerin fit for distillation. The process described requires only a single tank. Patent dated June 9, 1891, granted to O. C. Hagemann: First treat the spent lye with lime or other earthy oxide or hy¬ drate capable of combining with soapy or rosinous bodies; an in¬ soluble precipitate settles to the bottom or is filtered out; evapo¬ rate to salt-saturation point; remove the liquid, add hydrochloric or other acid to point of neutralization; cool to 30° C. or below; add a solution of animal albumen or caseine or other suitable proteine body which can be rendered insoluble by adding to its dilute alkaline or neutral solution a mineral acid in slight ex¬ cess, or a metal salt of an acid reaction, all in the presence of much sodium chloride, and provided that the mixture may be heated to complete such rendering insoluble of the proteine body. A good proportion is one part of blood albumen to about twelve hundred parts of the liquor, but more is required with very im¬ pure lye; now add to the liquor hydrochloric or another suitable acid or a metal salt having an acid reaction, whereby the sapon¬ aceous constituents contained in the lye are decomposed and in¬ soluble fatty and resinous bodies are formed, and the proteine ingredient previously added is being acted upon simultaneously. The decomposition of the fatty bodies thus takes place in the ubiquitous presence of the proteine ingredient, which is likewise rendered insoluble, and is engulfing the fatty bodies as soon as separated. The presence of the proteid ingredient predisposes the decomposition of fatty bodies to become speedy and very complete on account of the insolubility of the proteid precipita¬ tion, and also on account of the basic nature of the metallic pro¬ teid compound formed. Then gently heat the liquor to cause more complete separation and afterward obtain the clear liquor by filtration or any well-known means. The metal salts pre¬ ferred are aluminum, copper, iron, tin, chlorides, or sulphates, and others which may satisfy the requirements, as above ex¬ plained. The heating of the treated liquor is more especially required where an acid had been employed for the decomposition of the saponaceous bodies that were contained in the lye, and may be dispensed with in some cases where metal salts had been used. To the liquor thus purified now add soda, either caustic or carbonate of soda, so as to render the liquor very faintly alka- Glycerin and Its Recovery from Waste Lye. 403 line, and heat to about 80° centigrade, whereby albuminous mat¬ ters coag’ulate and fall to the bottom. Finally boil the liquid to about 150 centigrade, thereby evaporating- more water, causing- the salt which is carried in the liquor to crystallize. This salt may be washed and used over ag-ain in the manufacture of soap. The first operation—namely, that of adding- lime to the crude ly e —may be omitted. Such omission, however, would render the treatment more expensive. One also may apply the treat¬ ment as described hereinbefore, to follow the preliminary con¬ centration to “salting--point,” to soap-lye not preliminarily so concentrated, or may g-o further in concentrating- previous to such treatment. Under date of Sept. 1, 1891, J. Van Ruymbeke patented the following-: First treat the lye with an acid (muriatic preferred) to neutralize about % of the free alkali of the solution as pre¬ viously determined by test. Then add sulphate of iron or of al¬ uminum to complete said neutralization; this causes a precipi¬ tate of rosinous matter, fatty acids, insoluble soaps of iron or aluminum, some hydrate of iron or aluminum and sometimes, also, albuminous matter; decant or filter. Next evaporate to re¬ move the salts as far as possible and any remaining - impurities at the same time; the salt is crystallized out by running-the liquid from the filter press to a tank with steam-coils, which are placed at some distance above the bottom, in which it is boiled till the consistency desired for distillation; the salt settles to the space below the coils and may subsequently be reg-ained by a centrifug-al filter. The crude gdycerin is in condition for distill¬ ation. During- the evaporation the heat of the liquor is increased as it becomes more dense; if it is evaporated in the open air it is continued till the temperature rises to about 290° F., ora little over. But if the evaporation is effected in vacuum, the density must be the g-uide instead of the temperature. On cooling-, sul¬ phate of soda crystallizes out and is removed previous to distill¬ ation. The distillation is effected as follows: The solution is placed in a still of any suitable form, which is connected with suitable devices for producing-and maintaining- a hig-h vacuum within the still. The still is heated with com¬ mon or saturated steam, either by means of a coil within the still, steam-jacket around the outside thereof, or any other ordi¬ nary way. Free steam required for distillation is injected into and throug-h the heated liquor within the still, as usual; but this 404 Glycerin and Its Recovery from Waste Lye. steam in this process must be common or saturated steam. The steam both for the heating - device and for injection may be taken from the same source of supply, if desired. The object is to avoid the use of superheated steam, especially the steam which is in¬ jected directly into the liquid. Under a high vacuum it is pos¬ sible to successfully distil glycerin and other fatty substances with common or saturated steam only at a temperature not ma¬ terially above 300° Fahrenheit, which is the limit in this pro¬ cess. The result of this distillation is asubstantially pure glyce¬ rin, the salt, of course being left in the still; but ordinarily it will not be sufficiently concentrated for commercial purposes. It is only necessary then to concentrate this product of the still by any ordinary method of evaporation. Evaporating-pans such as are ordinarily used for concentrating liquids are suitable for this purpose, and upon bringing the liquid to the proper degree of concentration the glycerin is ready for the market. In reference to this patent, as compared with previous ones, the inventor states: “There are the following differences between myprocessde- scribed above and prior processes referred to. Instead of entire¬ ly neutralizing the free alkali with acids, I only partially neu¬ tralize with acid and then complete the neutralization ot the free alkali by the addition of metallic salts. The separation of the crude glycerin from the precipitate is effected by a filter-press. The crude glycerin is separated from the solution of salt in glyc¬ erin by distillation with common or saturated steam under a high vacuum. These differences result in the following advantages: By my method of neutralizing the free alkali of the lye I entire- ly obviate the danger of the presence of acid or metallic salts in the clarified solution. There will be no acid, because only a por¬ tion of the amount required for neutralization being used it will, of course, be entirely taken up. There will be no metallic salts, because in my method of finishing the neutralization of the free alkali by adding metallic salts there results a double decomposi¬ tion, metallic insoluble soaps being formed and the mineral acid thus freed combining at once with the soda contained in the soaps decomposed, while the unneutralized free alkali will unite with the acid of the metallic salts to produce mineral salts of soda and metallic hydroxides. Now, all these substances are insoluble, and hence may be entirely separated from the liquid. Furthermore, these substances form a precipitate which is sufficiently hard and Glycerin and Its Recovery from Waste Lye. 405 firm to permit the use of a filter-press in effecting- this separa¬ tion. The metallic salts are therefore entirely removed from the liquid, because they are entirely taking- up in forming- the precipitates mentioned above, which may be entirely separated from the liquid. Furthermore, this separation may be effected by a filter-press, which effects a great saving of time, a very im¬ portant matter in a commercial process, and also effects a saving of liquor, because the sediment in separation by the settling pro¬ cess, being soft and bulky, retains considerable of the liquid, whiuh it is almost impossible to recover by washing. With the filter-press in my process, however, a solid cake is left which con¬ tains only a small percentage of liquor, and even this may be readily removed by washing in the press. In the process of dis¬ tillation I avoid all danger of burning the glycerin, for the tem¬ perature of saturated steam is very constant and easily main¬ tained at about 300° Fahrenheit, which is not sufficient to injure the glycerin in any way, and in no case in my process should the temperature be carried materially above 300° Fahrenheit, which temperature I make the definite limit in the practice of my pro_ cess so far as the distillation is concerned. The successful use of saturated steam for this distillation is, however, dependent entirely upon carrying on the process under vacuum, and a very high vacuum at that. I have found that a vacuum of twenty- eight inches or more is absolutely necessary to this process, and I limit my improvement to this very high vacuum. “I am aware that heretofore glycerin has been distilled with superheated steam and under vacuum; but I believe I am abso¬ lutely the first to successfuly distil glycerin at the low tempera¬ ture of 300° Fahrenheit. In fact, in the very latest text-books of which I have any knowledge, it is stated that glycerin distils under vacuum at 350° Fahrenheit and not lower. “Of course in the practice of my process slight immaterial variations in the degree of vacuum and in the temperature will occur, so that I do not mean to be understood as fixing the limit of vacuum at exactly twenty-eight inches or of temperature at exactly 300° Fahrenheit; but the racuum cannot be materially lower nor the temperature materially higher than the limits named above. “It will be noted that I here provide a complete process for the production of commercial glycerin from spent lye. The ob¬ ject of my invention is not to obtain crude glycerin simply, but 406 Glycerin and Its Recovery from Waste Lye. the finished article ready for the trade, and the latter part of my process may be applied to the purification of crude glycerin ob¬ tained by some method other than that which I have described above.” On the same date with the last patent a second one was granted the same inventor on certain apparatus for carrying* out the process. It consists of an open tank for waste lye (tank A) placed so that the lye can run from it by gravity into a second tank (tank B) placed near it on a lower level; this second tank is followed by an ordinary pump (referred to hereafter as C) and this in turn pumps the lye to a filter press (referred to below as B) which again stands on an elevated platform. From the filter press the lye finds its way by gravity to an open, funnel-shaped evaporating pan (L) which is provided with an ordinary steam coil. Next follows another pump (G) which pumps to another tank (H) placed on the same level with the evaporating pan. A centrifugal machine (I) is placed conveniently above the last mentioned pump and discharges also into the same tank as does the pump. Next comes a vacuum still (K) of peculiar construc¬ tion; followed by a cooler or condenser (M) discharging into a closed receiver (N) provided with a water column and vacuum gauge; an ordinary vacuum pump maintains a vacuum in the re¬ ceiver and through it in the cooler and in the still itself. Finally, the receiver is connected with an ordinary vacuum pan (P) such as is used for concentrating liquids. The method of using the apparatus for the process last described is given by the inventor as follows: The tank A is filled or partially filled with the spent soap-lye and the quantity contained in the tank determined in any con¬ venient way. Three-fourths of the liquid in the tank A is then drawn off into the tank B, and to this liquid in tank B there is added a sufficient quantity of muriatic acid to exactly neutralize it. The remaining fourth of the liquid is then let down from the tank A into the tank B and mixed with the neutralized \ye in the latter. This operation affords a convenient way of effect¬ ing an exact three fourth neutralization of the entire quantity of lye. It may be done in some other way; but this mode is very convenient and at the same time certain. To this liquid in tank B, three-fourths neutralized, there is then added a quantity of persulphate of iron, equivalent to one-third of the acid used, and well mixed therewith, whereby a complete neutralization of the Glycerin and Its Recovery from Waste Lye. 407 free alkali is obtained and a double decomposition of the soapy matter. The liquid is now in proper condition without any further treatment for separation in the filter-press D,to which it is transferred by the pump C. By the operation of the filter-press the clear liquid is received in the pan d\ and thence delivered directly into the evaporating-pan E, while the precipitate is left in the press in the form of a cake. The liquid received in the evapor¬ ating-pan from the filter-press is crude glycerin, salt, and water, which is then evaporated in the usual way by means of the steam- coil in the said pan. During this process of evaporating the salt crystallizes out and drops to the bottom of the tank, which effect is greatly facilitated by the arrangement of the coil away from the sides of the tank, for the settling of the salt crystals is not impaired under this arrangement, as would be the case if the coil rested against the inner surface of the pan, in which lat¬ ter case the salt would gradually incrust the steam-pipes and so impair their action. The narrowing of the tank at the bottom also facilitates the separation of the salt crystals from the gly¬ cerin as the salt drops into the contracted bottom of the pan, leaving above an almost pure solution of glycerin and some salt, the evaporating process being continued until the water is most¬ ly boiled off and the most of the salt crystallized out. The liquid is drawn off from the evaporating-pan and delivered into the tank H by the pump G, in which it is allowed to stand and cool, thus crystallizing out some more salt and also sulphate of soda, which settles at the bottom of the tank. These salts settling at the bottom of the evaporating-pan and the tank H are removed to the centrifugal machine I, by theoperationof which the crude glycerin solution remaining therein is separated from solids and runs off through the pipe ** into the tank H. The salts left by this sepa¬ ration are suitable for re-use in the manufacture of soap, and thus a saving is effected. The clear solution of salt in glycerin stand ing in the tank II is now drawn into the still K by the operation of the vacuum-pump, which still is especially adapted to the dis¬ tillation of the solution in question, and also of all kinds of greasy and fatty solutions, oils, &c. In this still the glycerin is distilled off and passes into the condenser. As already stated, I prefer to obtain the heat necessary for distillation by means of steam-coil, for then there is no danger of unduly heating the sides of the still, which would lead to burning or incrustation of some material upon the inner surface. At the same time I secure 408 Glycerin and Its Recovery from Waste Lye. a regular and equable degree of heat throughout the entire body of liquid. At the same time steam is injected directly into the liquid through the pipes /, whereby the liquid is agitated and still further heated. When steam is thus injected, especially if super-heated I have found that small crystals of salt are carried along with the vapors of distillation, which of course injure the distillate, which will be a clear glycerin, but a little salty. The diaphragm /’ ob¬ structs the upward movement of these particles of salt, thereby preventing them from passing over with the vapors of distillation. The vapors are drawn from the still into the condenser M, where, as they pass through the flues, they are condensed by the action of the constant current of cold water flowing up through the cylinder around the tubes and collect in liquid form at the lower end of the condenser, and this liquid is discharged into the re¬ ceiver N as a clear aqueous solution of glycerin. In this part of the operation I have found that it is desirable to have a vacuum of about twent}’-nine inches, under which the glycerin readily distills by the application of saturated steam at about sixty pounds pressure in the steam-coil of the still, at which low heat it is obvious that it is impossible to burn the material. By the op¬ eration of the vacuum-pump R the glycerin solution is transferred from the receiver N to the vacuum-pan P, where it is concentrat¬ ed in the ordinary way to any required density and the concen¬ trated glycerin drawn off therefrom through the gate-valve at the bottom. The result is a clear pure glycerin. The particular construction of the still affords some advan¬ tages. Whenever there is occasion to reach the interior of the still, it may be accomplished by removing only one-half of the top or head, and the same is true of the bottom, so that the still may be readily entered from the top or bottom for purposes of repair or removal of the salt or any other sediment remaining at the bottom of the still, and this can be accomplished without in any way disturbing the steam-coil in the interior of the still. The perforated diaphragm in this still is a feature of special im¬ portance in the distillation of a salty solution of glycerin. On Dec. 22, 1891, a patent was granted O. C. Hagemann and E. K. Mitting, for a process of using chloride of calcium in place of hydrochloric acid, for neutralizing, &c. On March 25, 1892, O. C. Hagemann obtained a patent on the use of chloride of calcium to neutralize free alkali in the \ye and render insoluble contained impurities; its action is to form Glycerin and Its Recovery from Waste Lye. 409 chloride of sodium and carbonate and hydrate of lime with the carbonate and hydrate of soda, and to render insoluble organic impurities. On May 31, 1892, A. Domeier and O. C. Hagemann patented a process as follows: The spent lye is mixed with a little caus¬ tic lime whereby insoluble lime-soaps are formed and carbonated alkali is causticized; after settling the clear liquor is first con¬ centrated and then boiled with fat or fatty acids or rosin to take up the alkali present; the soap formed thereby is naturally grained out by the salts present. The liquor is again drawn off (and the lime treatment may be repeated at this stage). Next a solution of alum or a chloride (of iron, tin, or zinc) is added to precipitate fatty and resinous acids; then follows settling and an addition of caustic or carbonated alkali to precipitate any excess of alum or of chlorides and of albuminous matters. After again settling follows evaporation by boiling to a sp. gr. of 1.300 at 15 C., and removal of the salt which crystallizes out, in accordance with patents granted May 6, 1889. June 26, 1894, a patent was granted E. K. Mitting, as fol¬ lows: Milk of lime is added to the lye, about one-fifth to one- third per cent of the lye, settled and the clear liquor drawn off; boil till nearly saturated with salt; treat again with lime, settle, decant or filter; boil with fat, fatty acid or rosin to remove all free alkali; draw off the lye and again treat with lime to remove fatty and rosinous matters still remaining; filter or decant; boil down till boiling point is at about 300° F. On the same date two patents were obtained by J. Van Ruymbeke, one for extracting glycerin from glycerin foots, the details of which hardly belong to the present subject, and the other patent on a process of recovering glycerin, common salt, and Glauber’s salt from spent lye. Drawings of a plant designed for the purpose accompany the patent. There is a series of con¬ nected settling tanks (or a single tank with compartments) into which the lye is run in order to drop heavy impurities and to permit lighter ones to be skimmed from the top; next the clari¬ fied lie passes to a liming tank for treatment with slacked lime, and then it proceeds to a mixing tank; the free caustic and car¬ bonated alkali is then determined and ferric sulphate added in quantity just sufficient to neutralize this free alkali. Now the lye passes through a filter press, being previously heated if neces¬ sary to precipitate more fully the ferric hydrate and ferric soap 410 Glycerin and Its Recovery from Waste Lye. formed. The lye now contains still some ferric hydrate, acetate, and other salts, hence it goes to another tank where it can be brought to a boil to precipitate these; it passes a filter press again and then is ready for evaporation. The first salt now pre¬ cipitating is mostly sodium sulphate, later the sodium chloride precipitates more freely. Evaporation is continued to a point of 28° B. (30° B. at 15° C.), when the product is about 50 per cent glycerin and most of the salt originally in it has separated. For evaporation a vacuum apparatus is preferred to an open vessel; from this the salt is drawn off at intervals, the adherent lye drawn off by suction through a false bottom in the salt tank, and the salt washed by steam and condensing water to make it ready for use again. The lye of 30 B. as above is further concentrated to 34° B., and more salt thereby removed. The result is crude glycerin or glycerin saturated with salt and some impurities, and is ready for distillation. In place of ferric sulphate, the use of some other soluble ferric salt (e. g. chloride) or a salt of al¬ uminum (as the sulphate) is provided for in the same patent. On July 17, 1894, a patent was granted E. K. Mitting, on a process as follows: If the lye contains free alkali worth recover¬ ing or is very dark it is treated with lime to clarify it and per¬ haps also to causticize carbonated alkali; settle and decant or filter; evaporate to about half its bulk; if caustic is present boil with fat, fatty acid or rosin. With some lye these preliminaries are unnecessary and the proceeding is at once as follows: Add bi-sulphate of soda till no more turbidity or precipitate is pro¬ duced and the lye is acid in reaction, agitating thoroughly; de¬ cant or filter; heat to 80 C. and neutralize with soda or lime; filter or decant and then evaporate till it boils at about 300° F. On Aug. 13, 1895 a patent was granted H. J. Morrison of Clifton, O., on the removal of salt and organic impurities from spent lye by first concentrating and then treating with ammonia and then with carbonic acid gas, thereby producing bicarbonate of ammonia which, with the sodium chloride, forms ammonium chloride and sodium bicarbonate. An excess of ammonia is then to be boiled off, whereupon a carbonate or oxide of calcium (or other metal or alkali) is added to decompose the ammonium chloride; calcium chloride forms and is made insoluble by addition of sulphuric acid which gives rise to calcium sulphate and hydro¬ chloric acid; oxide or carbonate of lead then form an insoluble chloride, which is removed with the other precipitates. CHAPTER XXI. t The Simpler Tests and Examinations in the Soap Factory. The examination of raw materials, such as fats, alkali, es¬ sential oils, &c., as well as of the several products of the soap factory, involves in many cases comparatively simple manipula¬ tion only, which can be of immense benefit however; it is also true that in other cases the highest chemical skill is barel} 7 (if at all) sufficient to determine the quality and purity of raw ma¬ terials purchased, or to follow up the manufacturing- process through its various stages. Consequently large factories have in their employ thoroughly trained chemists whose constant ex¬ aminations frequently prevent loss through purchases of adulter¬ ated articles, control the workings of the manufacturing pro¬ cess, determine the satisfactory result of the several steps taken and the quality of the final products, experiment in new direc¬ tions, examine competitive articles, and in general are of great assistance in the successful conduct of these large enterprises. The smaller factories, in which no chemist is regularly em¬ ployed, either, in urgent cases, send their materials for exami¬ nation to chemists elsewhere, or rely upon what simple tests they can themselves make without such assistance, or—as a last re¬ sort—they go without the examinations desired. It is not within the province of this book to serve as a guide through the very intricate manipulations and calculations which enter into certain tests often made in factories which, like the soap factory, rest on the foundation of chemistry, as that is a large subject by itself, amply taken care of by innumerable books for that special purpose, and of interest only to the trained chem- 412 The Simpler Tests and Examinations in the Soap Factory. ist. But in a book intended, like the present one, to give all that is of practical value to the practical soap maker , there should evi¬ dently be room for an account of those simpler tests which also a non-chemist can readily learn to make, and by which the prac¬ tical soapmaker can avail himself of at least many of the advan¬ tages possessed by larger establishments. The aim of this chapter, then, is to collate and describe in detail such tests as can be applied to advantage in the soap fac¬ tory, without the application of very elaborate instruments, and without previous chemical training, as a matter of course, there¬ fore, tests selected for the following pages are not always those which the professional chemist would prefer when, equipped with a complete laboratory, he is looking for the most accurate results attainable; but notwithstanding this, the tests given are in all cases sufficiently accurate to give highly valuable returns for the trouble taken i?i carrying them out; nor is it to be forgotten that the average chemist, not being a practical soapmaker, also labors under certain disadvantages which often affect the value of his services so much that the simpler tests made by the practical man may be much more useful after all. A small number of utensils or instruments—the costliest of which is a good pair of scales—will be useful for so many impor¬ tant examinations, that in making the selection of the following tests we have given preference—other things being equal—to those which permit of the use of the same outfit always, so that in following these directions a minimum cost is combined with maximum of efficiency and practice. Including the scales, the instruments and materials required for making all the following ' tests can be procured for probably $35; if it should happen that led on by these, the reader should in time take an interest in more difficult work and arrange a more pretentious laboratory, he will never regret this modest start. Preliminary Remarks. Have water supply, gas burner or spirit lamp, water bath, and if possible a steam supply handy. If you can have a drying oven heated by steam and catch the waste steam for a supply of distilled water, it will be a great con¬ venience. For experimental work their is nothing so valuable as a min¬ iature soap kettle with steam connections, though work on a The Simpler Tests and Examinations in the Soap F actory. 413 large scale is of course not identical with that in a kettle hold¬ ing only say twenty-five pounds. A catalogue of some chemists’ supply house will illustrate a surprising variety of convenient appliances useful in experimen¬ tal work and should therefore be on hand in every soap factory. In some of the following tests, requiring weights and mea¬ sures, the metric system has been used for description; this is done for various reasons, as not only are calculations greatly simplefied by it and errors avoided, but apparatus required are now made largely on the same plan, current literature on the sub¬ ject is now mostly written in the same language, &c. ALCOHOL. To Test Alcohol as to its Origin i. e., whether made from potato, corn, wheat, or other spirit, the following simple process is recommended: Put a little of the alcohol with an equal quantity of ether in a test tube and shake thoroughly for a few moments. Now add an amount of water equal to both alcohol and ether. The former combines with the water and forms a lower layer, upon which rests the ether, which contains all the fusel oil of the original specimen. Withdraw with a pipette and evaporate the ether, and the odor of the resi¬ due will tell the source of the alcohol. Of course, one must be familiar with the odors of the various fusel oils. Tests for Water in Alcohol. 1. On adding a small amount of finely powdered, fused car¬ bonate of potassium to aqueous alcohol, and shaking, it becomes damp if the alcohol contains not less than about 98 per cent of absolute alcohol. In presence of more water it melts. 2. Alcohol over 98 per cent is miscible in all proportions with carbon disulphide. At 98 per cent it is only miscible with an equal volume of this liquid, and, if of lower percentage, with a proportionately less quantity (Barfoed). 3. Faintly ignited sulphate of copper, when added to anhy¬ drous alcohol, remains perfectly white. In presence of water, and shaking, it gradually acquires a blue color, which appears the more quickly the more dilute the alcohol is. 4. On adding a drop of alcohol containing 3 per cent of water to 3 or 4 c.c. of benzol, the liquid remains clear. If be¬ tween 3 and 7 per cent of water is present, a cloudiness appears; 414 The Simpler Tests and Examinations in the Soap Factory. if over 7 per cent, droplets separate. On dissolving- 1 c.c. of ben¬ zol in 2 c.c. of absolute alcohol, it requires the addition of 10 c. c. of an alcohol containing- 70.9 per cent by volume before a per¬ manent cloudiness appears (Hag-er). 5. If paraffin oil is dissolved in absolute alcohol or in anhy¬ drous chloroform, and this solution mixed with a few drops of an aqueous alcohol, and the liquid at once becomes turbid; 1.500th volume of water may thus be still detected (L. Crismer). BORAX. The impurities most commonly found with Commercial Borax may be divided into two classes, viz.: 1st. Those impurities which are insoluble in water, such as chalk, g-ypsum (plaster of paris), infusorial and other white earths. 2d. Those impurities which, like Borax, are soluble in water. Test for Earthy Impurities. To test a sample of Borax, for the insoluble impurities, take a portion of the pulverized material sufficient to cover a ten-cent piece, and place it in a wine-glass of hot water. If the water be¬ comes milky, and a white chalky sediment falls to the bottom of the glass, the Borax has been adulterated with an insoluble ad¬ ulterant. If, on the other hand, the whole dissolves, leaving onl} T a clear solution, the Borax may yet contain some of the soluble adulterants, such as alum, common salt, carbonate of soda, sul¬ phate of soda, or some other soluble sulphate. Test for Alum. To test for the soluble impurities, take sufficient of pow¬ dered Borax to cover a twenty-five cent piece, and dissolve in a tumbler of hot water. Place a portion of this solution in a wine-glass and add a few drops of washing ammonia. If a white precipitate forms, alum has been added. Test for Carbonates and Sulphates. To another portion of the liquid, add some muriatic acid. An effervescence shows the presence of an adulteration with a soluble carbonate. After the effervescence has ceased, add a few drops of a The Simpler Tests and Examinations in the Soap Factory. 415 strong- solution of chloride of barium. If the solution becomes milky, either immediately or after the lapse of a few minutes, the Borax has been adulterated with some soluble sulphate. Test for Salt. To a third portion of the liquid, add some nitric acid. An effervescence shows the presence of a carbonate. When this sub¬ sides, add a few drops of nitrate of silver, and heat the solution. If salt has been added, it will become milky. Test for Soda. As a quick test for carbonates, place sufficient of the Borax to cover a ten-cent piece, on a saucer, and add a few drops of strong vinegar. If the material effervesces, it has been adulter¬ ated by the addition of a carbonate (sal soda, etc.) ESSENTIAL OILS. In the list and description of essential oils (Chapter XVI.) are given a number of simple examinations adapted to the oils under which the tests are given. To these the reader is referred in every case for additional information when any particular oil is to be tested, but it remains to speak of certain general features of essential oil examinations: An examination of an essential oil comprises, in general terms: A: Examination of physical characters. 1) Color, odor, consistency. 2) Specific gravity. 3) Optical rotation. 4) Solubility in alcohol, &c. B: Estimation of percentage of certain valuable constit¬ uents found in certain pure oils, as linalyl acetate in oil of bergamot, citral in oil of lemon, &c. C: Tests for proving directly the presence of certain sus¬ pected adulterants. D: Special tests for given cases, as acidity, saponification, iodine absorption, and a great many other chemical tests. As those who make it a practice to adulterate essential oils are in many cases familiar with all the methods of examination, they frequently succeed in imitating in their adulterated pro¬ ducts also the specific gravity, or the optical rotation, or some of the other characteristics of the pure oils, so that it is impos- 416 The Simpler Tests and Examinations in the Soap Factory. sible in many cases to detect adulteration by simple means, or even by any means whatever for that matter. But as a rule it is not possible to obtain for purposes of adulteration cheap sub¬ stances that are not readily detected and at the same time do not effect either the specific gravity nor the solubility of the oil in al¬ cohol, nor the optical rotation. As to the color and consistency, these vary in nature within certain limits and the sophisticators easily keep within the natural limits, so these factors are ordin¬ arily of little assistance. The odor is still one of the best guides to the purity and strength of an oil and must be carefully observ¬ ed, but it presupposes the possession of two things by no means as common as desirable, namely: thorough acquaintance with.the pure oils and a well-trained sense of smell. The test for solubil¬ ity in alcohol is in many cases useful, as certain common adult¬ erants are less soluble than the pure oils. The estimation of the percentage of certain odoriferous constituents in a sample of oil is useful in some cases, as the percentage is lowerd by adult¬ eration with turpentine, fatty oils, alcohol, &c., &c., but as such tests are difficult to make at best, applicable only in few oils, and natural oils vary widely in some instances, this method of testing is somewhat limited in its usefulness; for instance, much is made of the ester contents of lavender oil, but while pure French oil contains at least 30%, the highly-valued English oils contain less than 10%. If it is impossible by the most scientific and skilled methods to positively differentiate qualities and detect all adulterations, too much must not be expected of course from simple tests that can be made by non-experts, but the description of oils in Chapter XVI and the following paragraphs contain much that is of prac¬ tical assistance and that will go far towards securing good oils. In making an examination of any essential oil, the deter¬ mination of its specific gravity is properly the first thing to be done, as most forms of adulteration affect it; the sp. gr. of each oil has been given in the descriptive list and, while slight varia¬ tions are not proof positive of adulteration, marked variations up¬ ward or downward are extremely suspicious; an increase in specific gravity of most oils follows adulteration with fatty oils, essential oils of higher sp. gr. &c., while a decrease usually results from alco¬ hol, of less sp. gr., &c. The determination can be made by a special hydrometer or the Westphal balance or the picnometer. Its value varies with the oil to be examined; thus the sp. gr. of The Simpler Tests and Examinations in the Soap Factory. 417 lemon oil is changed but little by adulteration with turpentine oil used either alone or together with orange oil; in other cases it may be of the greatest service. Optical rotation: An optical instrument, the polariscope, is used for determination of this factor; it frequently gives very useful indications, but owing to its cost few soap manufacturers will care to invest in the apparatus. In some cases its tell-tale in¬ dications have been safely circumvented by the adulterators, as in the example just quoted of lemon oil when mixed with oils of turpentine and orange. The test of the solubility of an oil in alcohol, where appro¬ priate, is easily and cheaply made and for a number of oils is a fairly valuable one. By it are discovered adulterants less soluble than the pure oils, such as fatty oils,.turpentine oil, and cheaper essential oils of less solubility, provided they are present in not too small quantity. It is necessary of course, in making this test, to strictly adhere to the amounts and strengths of al¬ cohol prescribed in the test. Adulteration with fatty oils is usually tested for by letting a few drops evaporate on clean white paper; pure essential oil does not leave a grease spot; if such a spot remains it is not neces¬ sarily a sign of adulteration, however, as it may also be the re¬ sult of a faulty process in making or in preserving the oils. This test may be modified by evaporating a few drops of the oil in a watch crystal placed on a water bath and examining the residue, if any, for oil, rosin, &c.; on treating the residue with alcohol, it will dissolve if it was castor oil or rosin; on then adding water, in the case of rosin there will be a flaky precipitate, but if it was castor oil it will separate in the form of an oily layer; if the resi¬ due was not soluble in the alcohol it is some fatty oil other than castor oil. Camphor may be detected in oil of peppermint, orange, lav¬ ender, cedar wood, caraway, &c., by the following test—(which, however, shows the same reaction with oil of sassafras and a very similar one with nutmeg and pimento). Place a drachm of nitric acid (sp.gr. 1.42) in a test tube, add one drop of the suspected oil, and agitate gently. The color of the mixture may vary from light yellow to red. If the oil is pure the red color will disappear in from twenty minutes to two hours. If oil of camphor is present the red color will remain for twenty- four hours, and even longer, if not exposed to too strong a light. 418 The Simpler Tests and Examinations in the Soap Factory. This test is reasonably delicate, as less than 5 per cent of oil of camphor may be detected by it. Alcohol, according- to Hag-er’s suggestion, is most easily de¬ tected by the following test which depends upon the insolubility of the essential oils in glycerin, and consists in agitating a de¬ finite, accurately weighed quantity of the essential oil, and of glycerin, together in a test-tube, and subsequently weighing the glycerin, any increment being due to the alcohol taken up by it from the oil. The details are thus given by Hager: Take a thin- walled graduated cylinder, place in it a quantity of glycerin, and accurately weigh the whole. Add the suspected oil, using a lit¬ tle more in volume than of the glycerin. Shake for five minutes, then set aside until the turbid, milky liquid separates into two clear layers, the oil being uppermost. If the latter is not quite clear, it can easily be made so by warming it up to about 120 F. by letting the cylinder stand in hot water for a few moments. Remove the bulk of the oil with a pipette, and the remaining traces with blotting paper, and again weigh the cylinder and its contents. Any increment in weight may be accepted as due to alcohol, and, of course, by weighing the oil, we get the per¬ centage of adulteration. The only drawbacks to the accuracy of this simple process are, first, that certain essential oils contain an acid principle, soluble in glycerin; and, secondly, certain of the oils are soluble (to a very slight extent only) in alcohol and glycerin. The oils containing the acid principle alluded to are the oil of cloves, oil of cassia and oil of almonds (essential). The evidence of the presence of the acids is a turbidity in the gly¬ cerin, greater or less, according to the amount of the acid. The second objection is so slight as to be scarcely worth noting, and unless very marked, the same may be said of the first. Finally, after all, what is wanted in buying an oil is full strength and fine aroma, and useful as other tests are, they are asyet too incomplete to be relied on alone, especially since an oil ma} 7 be pure and answer all scientific tests for purity, and yet have suf¬ fered from faulty methods of manufacture, adverse weather con¬ ditions, during the growth of the raw materials, bad storage, &c. Hence, after all, there is great need of examining the smell of an oil to judge of its quality. This manner of testing is carried out in practice in several ways, the best of them none too good—the others beyond comment. Passing over the simple smelling at the open neck of the bottle, at the cork, and at the hands between The Simpler Tests and Examinations in the Soap Factory. 419 which a few drops of the oil were rubbed, the next best and usual practice is to dip clean blotting- paper into the oil and smell at this paper from time to time, noting- the strength, delicacy, and lasting quality of the odor. By using the same size of paper slips, dipping them equally deep into different samples of oil, till saturated, and exposing them (hanging free) in the same place to gradual evaporation, a fair comparison can be made by an educated sense of smell. In place of blotting paper the kind known as glazed paper can be used to advantage, as it absorbs less of the oil and this evaporates more freely and evenly in con¬ sequence. Great accuracy, cleanliness, and surroundings free from odor, are required for this kind of work, besides practice. The paper slips are best marked on the back for identification, and the order of smelling them should be occasionally reversed, in order to avoid errors of judgment or prejudice from creeping in. FATS AND OILS. The large number of special works on the examination of the numerous fats and oils testify to the vastness of this field, and to them the reader must have recourse if he desire to enter fully into the subject. There are however a few comparatively simple tests which can be made by every practical soapmaker and which answer most of the ordinary requirements. Taking Samples: According to the nature of various fats, packages, and methods of filling, it is evident that impurities may be either distributed uniformly or they may c'ollect in cer¬ tain parts of the packages. To obtain a fair sample it is there¬ fore necessary to either take it from several parts of the package or to empty the latter, melt and mix, and then take the sample. If melting by open steam is used, the water added thereby will interfere with the examination for water in the stock Tallow: Tallow may contain water, various adulterants and animal impurities and dirt, and may be lowered in quality by admixture of cheaper fats. Its examination takes cognizance of the color, grain, odor, freedom from free fatty acids, water &c., and hardness. The melting point is one of the most valu¬ able indications of the quality of tallow; instead of on the melt¬ ing point of the tallow itself, whose determination by various methods does not give uniform results with the same tallow, it 420 The Simpler Tests and Examinations in the Soap F actory. is safer to rely on the melting - point of the fatty acids separated from the tallow. Melting Point of Tallow: Into a thin-walled glass tube of an internal diameter of 3 to 4 mm. draw a little of the melted tallow and let congeal thoroughly; then place the tube into a beaker with water so that the water is slightly higher in the glass than the tallow; apply heat slowly, having a thermometer in the wa¬ ter, till the fat is floated to the surface by the water entering from below. The temperature of the water at which this occurs is the melting point. Melted fat does not congeal again until a temperature more or less below the melting point is reached; at the moment of congealing its temperature rises again at first. The congeal¬ ing point of good tallow is not below 88 or 90 F. Another method is to apply the fat to the bulb of a thermo¬ meter, introducing the latter into water, warming, and noting at which temperature the fat becomes detached and rises. The Titer Test of Tallow: By this is meant the determina¬ tion of the solidifying point of the fatty acids separated from the tallow. The methods in vogue comprise saponification of the sample with mixed alcohol and soda lye (Dalican’s test) or with potash lye (Wolfbauer) or with alcoholic lye (Tate), and separation of the fatty acids by sulphuric acid, followed by their examination for congealing point. The harder the tallow, in other words the higher its melting point and that of its fatty acids, the richer is the tallow in stearine. This test has several advantages over the simple determina- tion of the melting point of the tallow itself; for one thing its results do not show the uncertainty and inaccuracy which arise from the many different methods followed in finding the melting point of tallow. Again a tallow containing more or less free fatty acid may have been treated with alkali to neutralize these acids, whereby a partial saponification and consequent harden¬ ing of the mass results; this deception would not be disclosed by simply ascertaining the melting point of the tallow, but a separa¬ tion of the fatty acids will lead to a correct estimate of the tal¬ low. Age also affects the melting point of tallow differently than that of its fatty acids. As in all these tests, the one now under consideration appears in numerous modifications, but the following of Wolf¬ bauer answers all purposes: The: SimplerTests and Examinations in the Soap Factory. 421 120 grammes of the tallow are melted, without heating - much more than necessary, in a beaker; mix with 45 cc. of a lye made from 1.25 kilo pure caustic potash and 2 liters of water; stir till a perfectly homogeneous mass is obtained; cover the beaker and set aside in a place kept at 100 C.; stir now and then and after two hours see if all is saponified—this is done by dis¬ solving a little of it in 50 per cent alcohol, which gives a perfect¬ ly clear solution if all is saponified—if not, the mass must remain in the hot place a while longer. The soap now obtained is boiled with dilute sulphuric acid (165 cc. of 18°) till the separating fatty acid floats as a clear layer on top; the mass is covered mean¬ while with a glass dish filled with cold water in order to pre¬ vent concentration of the acid liquid beneath. The acid solution is now drawn off from under the fatty acidsand the latter washed by boiling for 15 minutes with a mixture of 5 cc. concentrated sulphuric acid and 100 cc. water. After then resting and care¬ fully drawing off the acid water, boil again with 100 cc. pure water, rest again and remove the water. Now dry the fatty acids for 2 hours at 100 C. in an open glass vessel. It now re¬ mains to determine their congealing point. For this purpose a glass is used, 3}4. cm. in diameter, 15 cm. long, and filled to within 1 or l}4 cm. of the brim with the fatty acid. This glass is closed by a cork having a large perforation through which a thermometer is introduced, (loosely enough to permit stirring the contents with the thermometer). The lower % of this glass is then inserted in its turn through the perforated cork of a large wide mouthed bottle. Now the mass is stirred with the thermometer until it just becomes opaque, i. % per cent must still be deducted from the result to ob¬ tain the weight of the fatty acids. Another method, preferably where there is danger of vitiating the result by filling matter in¬ cluded in the cake of wax and fatty acids, is to dissolve the soap in water, separate the fatty acids by sulphuric acid as above and then shaking with ether; this is then poured off into a suitable weighed vessel, evaporated, the remaining fatty acids dried for' 2 hours in a drying oven, and weighed; 96.75 per cent of this weight is considered actual fatty acid. Unsaponified fat in Soap: Dry the soap perfectly; and finely powder the soap used to determine the proportion of water as above can be used for the purpose; extract with petroleum ether; evaporate the latter and the residue will be neutral fat or min¬ eral oil (hydrocarbons). By saponification of the residue if this is possible its nature can be further determined. Filling: Dissolve the soap, previously made into shavings, in 10 times its weight of alcohol of 90 per cent, assisting the solu¬ tion by the water bath; carbonate of soda, silicate, starch, &c., remain insoluble; filter and wash the precipitate with alcohol; dry it and weigh. To determine the nature of the water-soluble portion of the precipitate, extract it with cold water and examine portions of the extract; carbonate of soda is determined by titra¬ tion; silicate of soda is found by adding an acid to the watery solution, when the fatty acids rise to the top while the silicate forms a jelly at the bottom; this jelly is collected on a filter, washed, dried, and weighed; soap with silicate filling is not quite soluble in alcohol as the latter withdraws alkali from the silicate leaving the jelly-like mass which is insoluble. On boiling that part which is insoluble in alcohol, with water, if starch is present it will give a thick solution causing an intensely blue color with tinctureof iodine. Talc, silex, &c., are separated easily by their in¬ solubility in water; so far as mineral bodies alone are to be deter- 426 The Simpler Tests and Examinations in the Soap F actory. mined, as sand, pumice, silex, &c., a weight sample of the soap may be burned in a crucible, digesting the residue with hot water, filtering - , drying - the residue, and burning - the latter in a weighed crucible; the gain in weight of the latter is mineral matter. Sugar in soap: Dissolve a sample in water; separate by grain¬ ing - with salt; boil the liquid for half an hour with a few drops of sulphuric acid (to invert the sug-ar); neutralize with caustic soda; take a little of it into a test tube and add an equal amount of Fehling’s solution; boil; if sug-ar is present a red precipitate of cuprous oxide will form. Stock used. The question from what fats or oils a soap is made is always very difficult, and frequently impossible, to ascertain by chemical means. The practical soap maker can usually judg-e better than a chemist can ascertain the facts. A fair idea can sometimes be obtained by separating - the fatty acids and then examining - these for their melting - point, saponification number, iodine number, and certain characteristic reactions. When sever¬ al kinds of stock are contained in the soap, the examination is al¬ most hopeless. Rosin insoap : It is usually easy enough to tell if a soap contains rosin or not, but its proportion is more difficult to determine; in fact its determination is not possible by any method that could be consistently placed among - simple tests. As simple as any is Gladding’s method which consists, briefly stated, in separating the fatty acids of a sample of soap, dissolving them in 95 per cent alcohol, neutralizing with concentrated potash lye using phenol- phthalein as indicator, heating on a water bath to perfect saponi¬ fication, adding ether, shaking with silver nitrate to precipitate the fatty acids, drawing off the clear liquid, adding to the latter dilute hydrochloric acid, evaporating the clear liquid to dryness; the residue is considered to be rosin. This test in several modi¬ fications, and numerous others, are in use, which those who have the facilities for carrying them out are quite familiar with. Free alkali: The presence of free alkali (caustic or carbon¬ ate) is known by a red coloration produced when phenolphth- alein is added to an alcoholic solution of the soap. To determine its amount, a weighed sample is boiled with distilled water and then carefully grained with successive small portions of salt. Any free alkali remains in the salt solution which is drawn off, and its amount may be determined by titration on the same principle The Simpler Tests and Examinations in the Soap Factory. 427 as already described under the testing - of soda. Another method is to test 5 grammes of the soap with 75 cc. of neutral absolute alcohol, filtering - , and washing - well with hot alcohol. The filtrate is titrated, with phenolphthalein as indicator,to determine the free caustic. The insoluble portion on the filter is washed out with water and titrated with sulphuric acid, using - methyl orang-e as indicator, to determine the carbonate of soda. Glycerin in soap : To determine its presence, dissolve a small sample of soap in hot water, add dilute sulphuric acid to acid re¬ action, melt the fatty acids together with wax as already describ¬ ed, and remove same after cooling - . Exactly neutralize the remaining - liquid and evaporate on water bath. Sulphate of soda and g-lycerin (if present) will remain; treat these with alcohol (which does not dissolve sulphate of soda); filter and evaporate the alcohol; g-lycerin remains behind, if present. SODA AND POTASH. The examination of soda comprises testing of commercial caustic and carbonate, and sometimes of solutions of the same (lye.) As previously noted, when the purity of a caustic is known , the lye made from it can be directly examined with a hydrometer to tell its strength or quality; but as a solution of salt, or any other substance, also shows its degrees on the hydrometer, so a mixture of caustic and salt in solution shows higher degrees the more of either the one or theother or of both is present in the solu¬ tion, and consequently it is absolutely and unequivocally wrong to say that the quality of a sample of caustic of unknown com¬ position can be examined by dissolving it in water and testing it with the lye scale. If this is dwelt on too frequently in this book, it is because the error is so far spread that it is almost im¬ possible to overcome it. Another thing to bear clearly in mind is that the grades of caustic soda are based purely on the amount of sodium oxide in the same, irrespective of the latter being in the form of caustic or of carbonate; hence of two samples both correctly graded at say 70 per cent it is quite possible for one to contain 2 per cent more carbonate than the other (and of course at the same time 2 per cent caustic less). In examining caustic for its practical value it is therefore necessary to ascertain not only the total al¬ kalinity but separately the respective amounts of carbonate and of caustic soda. 428 The Simpler Tests and Examinations in the Soap Factory. The purity and strength of an alkali or of an alkaline so¬ lution is determined by ascertaining- how much sulphuric acid a g-iven amount of it will neutralize; this is the key to the process of testing- alkalies (alkalimetry) as well as for making-numerous other tests of use in the soap factory. For soapmaking- the caustic is used to neutralize/z//y acids; for testing- it one might ascertain how much fatty acid a certain amount of it can neutralize; but for simplicity and other practical reasons sulphuric acid is preferred to fatty acids in making such tests. As in measurements of any kind whatever a correct measure is the first requisite, so the sulphuric acid used in alkalimetry must be of known strength; in the following the pure article of 1.842 sp. gr. at 12° C. is understood throughout. 49 lbs. of pure sulphuric acid are neutralized by 40 lbs. of pure caustic soda. 49 lbs. of pure sulphuric acid are neutralized by 53 lbs. of pure carbonate of soda. 49 lbs. of pure sulphuric acid are neutralized by 56 lbs. of pure caustic potash. 49 lbs. of pure sulphuric acid are neutralized by 69 lbs. of pure carbonate of potash. If in the above table we substitute for the “lbs.”: grains, or drachms, or ounces, it would of course still be correct. Supposing now we had a sample of caustic soda of unknown purity, and found by a simple test that 40 grains of it neutral¬ ized exactly 49 grains of our pure sulphuric acid, we would then know that the caustic was of full strength, i. c ., is chemically pure 100 per cent caustic (— 77 l / 2 per cent sodium oxide). But if the 40 grains neutralized only y 2 or y as much of the pure sul¬ phuric acid, then its alkalinity is only >4 or % of the pure article. These simple principles once clearly understood , the following detailed description of the test will not only lose all mystery, but will give the key to many other tests that can be carried out in the soap factory to great advantage, such as alkaline strength in waste lyes, free alkali in soaps, &c. Bearing in mind all along then the foregoing, and coming to its practical application, we find that instead of making these tests by weight, it saves a vast amount of work if we dilute our sulphuric acid in a known amount of water and then simply measure the amount used for a certain The Simpler Tests and Examinations in the Soap Factory. 429 test; as the volume of dilute acid used is then our indication, this method is known as “volumetric analysis.” It is evident now that, if we dissolve a certain weight of our soda to be tested in water, and run into this the dilute sulphuric acid from a graduated vessel, till the soda and acid are just neu¬ tralized, the amount of acid used can be read off from the gradu¬ ations and a simple calculation will show the rest. This is called “titration.” There is now only one point more: how shall we know when enough acid has been run into our soda solution and the neutral point is reached? We may know this by making use of a few drops of litmus or a little phenolphthalein or methyl orange, (so-called “indicators”) which are introduced into the soda so¬ lution at the beginning of our test. Supposing we use litmus, the soda solution will color this a marked blue and this color remains as we run in gradually the acid; but at last a point comes when all the alkali has been neutralized by the acid and a single drop of the latter now changes the former blue color to red—the solution is no longer alkaline but has become slightly acid. In other words, alkaline solutions are blue with litmus and acid solutions are red. For ease of calculations and because the instruments used are ordinarily so graded, the following test is described in the metric system which should always be employed in such work. The Test\ There should be on hand for this class of work a pair of scales, a few glass beakers, a glass funnel and filter paper, a graduated glass tube holding 50 cc., with stop stock be¬ low (a so-called burette) from which the acid can be withdrawn drop by drop and the amount used read off, and a holder for the burette. There should also be one or several indicators such as mentioned before, some reagents called for in certain tests^ and the following “normal” or “standard” solutions: 49 grammes pure sulphuric acid diluted with enough water to make one litre. 40 grammes pure caustic soda diluted with enough water to make one litre. 53 grammes pure carbonate of soda diluted with enough wa¬ ter to make one litre. 56 grammes pure caustic potash diluted with enough water to make one litre. 430 The Simpler Tests and Examinations in the Soap F actory. 69 grammes pure carbonate of potash diluted with enough water to make one litre. Comparing- the amounts named for each of these five solutions with the table of neutralization a few paragraphs back, it will be seen that a given volume of the normal sulphuric acid solution exactly neutralizes equal volumes of all the other normal solu¬ tions. These normal solutions can be obtained from chemists’ supply houses if facilities for making them exactly are not at hand. Testing sodium carbonate: Weigh off 5 grammes of the alkali, place into a flask and make up with water to 250 cc. Fill the burette exactly to the 50 cc. mark with the normal sulphuric acid. From the flask measure exactly, into a beaker, 25 cc. of the al¬ kali solution and add a few drops of methyl-orange solution as an indicator (enough to give it a yellow tint); now run in the acid solution from the burette very carefully, drop by drop at last, stirring carefully, till the alkali solution turns pink which shows that all alkali is neutralized and the solution now contains a trace of free acid. (Litmus is less suitable for testing carbon¬ ate than is methyl-orange). Read off the number of cc. acid used, multiply by 0.053, and you have the weight in grammes of actual carbonate in the amount of solution tested. A simple self- evident calculation finishes the example. Potassium Carbonate is tested in the same manner, merely substituting in the final calculation the figure 0.069 for the 0.053. Caustic soda and potash are tested in the same way, substitut¬ ing the figures 0.040 and 0.056 in the final calculation. However, as the test does not show at all how much of the alkali present is caustic and how much of it is carbonate, this point can be as¬ certained as follows: Weigh off 5 grammes as before, dissolve in hot water (200 cc. ) and add 50 cc. neutral barium chloride so¬ lution, whereby barium carbonate is precipitated; settle, filter, wash the precipitate with water to get out all the caustic alkali; by now testing with acid and phenolphthalein as before we get the alkali present as caustic and the difference between the amounts of acid used in the two tests represents the amount of carbonate that was present in the sample before it was removed by the barium chloride. Another test for the purpose which gives probably more accurate results is as follows: Dissolve 2.65 grammes of the caustic in 50 cc. of water and titrate as before with the normal sulphuric acid, using phenolphthalein asindica- The Simpler Tests and Examinations in the Soap Factory. 431 tor and adding- acid drop by drop to the point of decolorizing-, stirring- from time to time; note amount of acid used. Now add 3 cc. normal acid, boil about 5 minutes to expel the carbonic acid and titrate back with lye, (The rationale of this is that in the first tritration all the caustic alkali is neutralized and half the carbonate is chang-ed into bicarbonate). The calculation now is as follows: Calling- the number of cc. of acid used for the first titration by the letter a, and those for the second b. then the sample contained: 2 (2 a-b) per cent actual caustic soda. 4 (b-a) per cent carbonate of soda. In making- these tests it is by no means immaterial which of the “indicators” named is used; for instance, in titrating- caustic alkalies cold, with phenolphthalein as indicator, half of the car¬ bonate present would appear as caustic, for the reason that bi¬ carbonate of soda (or of potash) is found by the carbonic acid escaping- from the first half of the decomposed carbonate, and this bicarbonate is neutral to phenolphthalein; if now methyl orang-e be added and the titration continued till the color chang-es, then the bicarbonate will have been turned into sulphate. Making a test in just this manner the calculation is as follows: Say 12.50 cc. of normal acid be required for titration with phenolphtha¬ lein, and 0.50 in addition to make the solution neutral to methyl orang-e; then 12.50 less 0.50 = 12 cc. is the volume neutralized by the hydrate, and 2x0.50 = 1 cc. for the carbonate in the sample. To make this test accurately it is best to dilute a gramme of the sample to 250 cc. and stirring- continuously while the acid is add¬ ed slowly. To test potash for soda : A fairly accurate and simple method for this purpose is based upon the insolubility of potassium bi¬ tartrate in diluted alcohol. The sample is dissolved in a little water and neutralized with a concentrated solution of tartaric acid (using- phenolphthalein—not litmus—as indicator) ; the same amount of tartaric acid solution as was required is then again added in order to change the tartrates formed into bitartrates. The bitartrate of potash will now mostly precipitate while the bitartrate of soda remains in solution; the addition of alcohol completes the precipitation entirely. Collect the precipitate on a filter and wash with alcohol till the washingsno longer redden litmus paper. Now the filtrate is titrated with decinormal (one- tenth the strength of normal) caustic potash or caustic soda, 432 The Simpler Tests and Examinations in the Soap Factory each cc. required corresponding- to 0.004 gramme of sodium hy¬ drate. The precipitate of pottassium bitartrate may be put in water and titrated also with volumetric alkali and phenolphtha- lein, each cc. corresponds to 0.056 grammes of potassium hydrate. TAR. Juniper Tar : Specific gravity varies from 0.978 to 1.102 at 15°C.; in many respects resembles pine tar; imperfectly soluble in 95 per cent alcohol (thus differing from pine tar); perfectly sol¬ uble in anilin (thus differing from birch tar); a watery extract does not give a red color when treated with anilin and hydrochl¬ oric acid (distinguishing it from pine tar); watery extract (1.20) colored reddish by addition of very dilute (1:1000 solution of iron chloride (birch tar extract colored green by same solution). Imperfectly soluble in 95 per cent acetic acid. Beech Tar\ Sp. gr. 0.925 to 0.945 at 20° C. (68° F.), hence floats on water; agitated with 10 volumes of water does not color the water, but the latter becomes markedly acid and is colored green by the addition of perchloride of iron to the water; if to 5 ccm. of the water is added 2 drops of anilin and 4 drops of hydro¬ chloric acid, a yellow color reaction ensues. If one volume of beech tar be agitated with 20 volumes of petroleum ether and filtered, a clear brownish liquid is obtained which does not be¬ come green when agitated with a diluted solution of copper ace¬ tate. Beech tar is but imperfectly soluble in oil of turpentine, chloroform, and absolute ether, (vs. pine tar). Perfectly solu¬ ble in 95 per cent acetic acid. Pine Tar : Sp. gr. 1.02 to 1.05 at 20 C. (68° F.), hence sinks in water if entirely free from air bubbles; shaken with 10 vol¬ umes of water the latter becomes colored yellow (vs. beech tar) and acid; the same water is turned red on the addition of iron chloride (instead of green as noted under beech tar); treated with anilin and hydrochloric acid, the color passes to red; the petroleum ether solution shaken with the dilute copper acetate solution (1:1000) is turned green (vs. beech tar); pine tar shaken with alcohol does not color the latter, but if it becomes cloudy it points to admixture with coal tar, kerosene products, beech tar, &c. Perfectly soluble in 95 per cent acetic acid, chloroform and absolute ether. The above tests are from the writings of Ed. Hirschsohn, well known by his examinations of wood tars. The Simpler Tests and Examinations in the Soap Factory. 433 Tar in General. To test the disinfecting* power of a given specimen is a com¬ plicated and even then unsatisfactory undertaking, it being based on a determination of the guayacol percentage and the degree of avidity. According to W. Adolphi a general idea of the quality of a given tar can be obtained by the following simple procedure: 5 parts by weight of pure caustic are boiled up with 75 parts water; to the boiling solution add 25 parts of tar and shake frequently while cooling. The dark solution, during the course of a few days of rest in a cool place, precipitates more or less of a smeary substance which, however, is soluble on adding more water; this precipitate is noticed in good as well as in bad tars and must therefore be considered as normal. Apart from this precipitate a good tar is perfectly saponifiable, but a poor specimen will yield on the surface of the above preparation a layer of unsapon- ifiable oil, especially if the alkaline solution is further diluted with four times its volume of water, /. e. in a solution containing 1 per cent alkali and 5 per cent of tar. A slightly turbid or milky appearance is permissible. PART VI. ' . Tables, Etc Caustic Soda and Caustic Potash Required for Making, or Contained in Lyes, of Different Strengths. Lye. Specific Gravity. 100 lbs. lye contain of Caustic Soda. Caustic Potash. 1° B. 1.0070 0.61 lbs. 0.90 lbs. 5° “ 1.0360 3.35 “ 4.50 “ 8° “ 1.0588 5.29 “ 7.40 “ 10° “ 1.0746 6.55 “ 9.20 “ 12° “ 1.0909 8.00 “ 10.90 “ 15° “ 1.1163 10.05 “ 13.80 “ 18° “ 1.1423 12.64 “ 16.50 “ 20° “ 1.1613 14.37 “ 18.60 “ 25° “ 1.2101 18.58 “ 23.30 “ 30° “ 1.2632 23.67 “ 28.00 “ 35° “ 1.3211 28.83 “ 32.70 “ 38° “ 1.3585 32.47 “ 35.90 “ 40° “ 1.3846 34.96 “ 37.80 “ 45° “ 1.4545 41.40 “ 43.40 “ 50° “ 1.5319 49.00 “ 49.40 “ If these lyes are made of chemically pure caustic alkali the actual caustic content is expressed by the figures. If the lyes are made of lower grades the actual caustic strength is pro¬ portionately decreased, as the grade of caustic alkali is lower. The degrees on the hydro¬ meter refer to a temper¬ ature of 60° F. in cool¬ ing from the boiling point to 60 F., lyes in¬ crease from 4^2 to 5 B. in density. Aukali Required for Saponification. There are required for the complete sa¬ ponification of Caustic Soda. Caustic Potash. 77*4 p.c. Cliern. Pure. 77 p.c. 76 p.c. 74 p.c. 70 p.c. 60 p.c. Chem. Pure. 100 Ibs.cocoanut oil* 100 “ tallow*. 17 42 lbs. 13.95 “ 17.53 lbs. 14.04 “ 17 76 lbs. 14.22 “ 18.24 lbs. 14.61 “ 19.29 lbs. 15.44 “ 22.5 lbs. 18.2 “ 24.4 lbs. 19.54 “ *These calculations are theoretical, and made on the basis of very pure fat. Fats and oils that contain impurities will absorb correspondingly less al Uali. The figures for grease, cotton seed oil, and other fats (except cocoannt oil) are nearly the same as for tallow. In practice for boiling soaps more alkali is required than stated above on ac¬ count of at least some unavoidable waste. For cold-made or half-boiled soap the above proportions are substantially correct, as no lye is run away in their manufacture. Cir¬ cumstances, of course, figure largely in actual practice. 438 Tables, Etc. Temperature of Wet Steam at Various Degrees of Pressure. As the pressure in the steam boiler rises the temperature of the steam is increased, so that for operations intended to evapo¬ rate considerable water from the soap an increased steam pressure gives the fastest result. Tp:mperature. Pressure. Degrees F. 32. 212 . 248. 275.. 293. 311. 320. 428. lb. per sq. inch. .08 . 14.70 . 28.83 . 45.49 . 60.40 . 79.03 . 89.86 .336.30 Expansion of Oils by Heat. When the quantity of oils and fats run into the kettle is re¬ gulated by measurement, the temperature of the stock is a not unimportant item, as in common with other liquids, oils expand by heat so much that, for instance, 1,000 gallons of oil at 32° F. will make 1,018 to 1,025 gallons at 75 c F., according to the kind of oil. This expansion is therefore more considerable in fats and oils than in ordinary fluids. Metric Weights and Measures. 1 Hectoliter (100 litres) = 26,4175 U. S. gallons. 1 Liter = 2,1134 American pints (=61.024 cubic inches.) 1 Kilogram (1000 grams) = 2,205 lbs. avoirdupois. 1 Oram = 15,4384 grains. 1 Kilometer (1000 meters) = 0,62138 mile. 1 Meter = 39,3795 American inches. 1 cubic centimeter (c. c.) = 16.23 minims. The prefixes used in the metric system have the following meaning: Kilo—meaning one thousand. Hecto—meaning one hundred. Deka—meaning ten. Deci—meaning one-tenth. Centi—meaning one-hundredth. Milli—meaning one-thousandth. Tables, Etc. 439 Avoirdupois Weight. 1 lb. = 16 ounces == 256 drachms. 1 ounce = 16 drachms. The pound avoirdupois equals 7000 grains in weight. There is no grain in the avoirdupois weight—as found in some tables— but only one uniform grain (that of the troy weight) exists. Troy (Apothecaries’) Weight. (U. S.) 1 pound-12 ounces = 96 drachms = 288 scruples = 5760 grains. 1 ounce = 8 drachms = 24 scruples = 480 grains. 1 drachm = 3 scruples — 60 grains. 1 scruple — 20 grains. Wine (Apothecaries’) Measure. (U. S.) The U. S. gallon contains 231 cubic inches and equals 0.83292 British gallon. 1 gallon = 8 pints = 128 fl. ozs. = 1024 fl. drachms= 61440 minims. 1 pint = 16 fl. ozs. = 128 fl. drachms = 7689 minims. 1 fl. oz. = 8 fl. drachms = 480 minims. 1 fl. drachm — 60 minims. Imperial Measure. The Imperial (British) gallon contains 277.27384 cubic inches and equals 1 gallon 1 pint 9 fl. oz. 5 fl. drs. and 8 minims of the United States gallons. 1 gallon = 8 pints=160 fl. ozs.=1280 fl. drachms=76800 minims. 1 pint = 20 fl. oz. = 160 fl. drachms= 9600 minims. 1 fl. oz. — 8 fl. drachms= 480 minims. 1 fl. drachm = 60 minims. THE THERMOMETER. « The thermometric scales chiefly in use are those of Fahren¬ heit, Celsius (better known as the “Centigrade” scale), and Reaumur, in which the interval between the normal freezing and boiling points of water is respectively divided into 180, 100, and 80 degrees. The Reaumur scale is but little used except in some parts of Germany. The several degrees compare with each other in this manner: 440 Tables, Etc. 1° F. = *55° C. or *44° R. 1° C. = 1*80° F. or *80° R. 1° R. = 2-25° F. or 1*25° C. The zero of both the Centigrade and Reaumur scales is placed at the freezing point of water, while with Fahrenheit’s thermom¬ eter 0° comes 32 degrees below, hence in converting any temper¬ ature on one scale to its equivalent on another, one of the following methods must be adopted: A given temperature in Centigrade deg. divide by 5 multiply by 9 add 32. The result is temperature in Fahrenheit deg. A given temperature in Centigrade deg. divide by 5 multiply by 4. The result is temp, in Reaumur deg. A given temperature in Fahrenheit deg. — 32 divide by 9 multiply by 5. The result is temp, in Centigrade deg. A given temperature in Fahrenheit deg. — 32 divide by 9 multiply by 4. The result is temp, in Reaumur deg. A given temperature in Reaumur deg. divide by 4 multiply by 9 add 32 equals temp, in Fahrenheit deg. A given temperature in Reaumur deg. divide by 4 multiply by 5. The result is temp, in Centigrade deg. It is, as a rule, only Centigrade and Fahrenheit degrees with which temperature are marked in this country. TABLE SHOWING CENTIGRADE DEGREES AND THEIR EQUIVALENT ON FAHRENHEIT’S SCALE. For the ready conversion of Centigrade into Fahrenheit de¬ grees, the following table will be useful. Fok Temperatures Below the Freezing Point of Water. c. F. C. F. C. F. C. F. C. F. c. F. — -4- + o 0 o o o o o o o o o o 40 40*0 33 27*4 26 14*8 19 2*2 15 5-0 < 19*4 39 38*2 32 25*6 25 13*0 18 0*4 14 6*8 6 21*2 38 36*4 31 23*8 24 11*2 17*778 0*0 13 8*6 5 23*0 37 34*6 30 22*0 23 9*4 — + 12 10*4 4 24-8 36 32-8 29 20-2 22 7*6 o 11 12*2 3 26*6 35 31*0 28 18*4 21 5*8 17 1*4 10 14*0 2 28*4 34 29*2 27 16*6 20 4*0 16 3*2 9 15*8 8 17*6 1 0 30*2 32*0 Tables, Etc. 441 For Temperatures Above the Freezing Point of Water. c. F. c. F. C. F. C. F. C. F. c. F. + + + + + + + + + + + + o o o o o o o o o o o o 1 33*8 68 154.4 135 275-0 202 395*6 269 516-2 336 636*8 2 35*6 69 156*2 136 276-8 203 397*4 270 518*0 337 638*6 3 37*4 70 158*0 137 278*6 204 399*2 271 519*8 338 640*4 4 39-2 71 159*8 138 280*4 205 401*0 272 521*6 339 642*2 5 41-0 72 161*6 139 282*2 206 402*8 273 523*4 340 644*0 6 42*8 73 163*4 140 284*0 207 404*6 274 525-2 341 645*8 7 44*6 74 165*2 141 285*8 208 406*4 275 527 -0 342 647*6 8 46’4 75 167*0 142 287*6 209 408*2 276 528*8 343 649*4 9 48*2 76 168*8 143 289*4 210 410*0 277 530-6 344 651-2 10 50*0 77 1706 144 291*2 211 411*8 278 532*4 345 653*0 11 5P8 78 172*4 145 293-0 212 413*6 279 534*2 346 654*8 12 53-6 79 174-2 146 294*8 213 415*4 280 536*0 347 656*6 13 55*4 80 176-0 147 296*6 214 417*2 281 537-8 '348 658*4 14 57-2 81 177-8 148 298*4 215 419*0 282 539 6 349 660-2 15 59*0 82 179-6 149 300*2 216 420-8 283 541*4 350 662*0 16 60-8 83 181-4 150 302*0 217 422-6 284 543-2 351 663*8 17 62-6 84 183*2 151 303-8 218 424*4 285 545-0 352 665*6 18 64*4 85 185*0 152 305-6 219 426*2 286 546*8 353 667*4 19 66*2 86 186-8 153 307-4 220 428 0 287 548*6 354 669-2 20 68*0 87 188-6 154 309*2 . 221 429*8 288 550*4 355 671-0 21 69-8 88 190*4 155 311*0 222 431-6 289 552.2 356 672*8 22 7P6 89 192-2 156 312-8 223 433*4 290 554*0 357 674-6 23 73-4 90 194*0 157 314-6 224 435*2 291 555-8 358 676*4 24 75*2 91 195-8 | 158 316*4 225 437*0 292 557-6 359 678*2 25 77*0 92 197-6 1 159 318*2 226 438*8 293 559*4 360 680*0 26 78*8 93 199-4 160 320*0 227 440*6 294 561-2 ( 361 681*8 27 80-6 94 201*2 161 321-8 228 442*4 295 563*0 362 683*6 28 82-4 95 203*0 162 323*6 229 444*2 296 564*8 363 685*4 29 84*2 96 204*8 163 325*4 230 446*0 297 566*6 364 687*2 30 86*0 97 206*6 164 327 -2 231 447*8 298 568*4 365 689*0 31 87-8 98 208*4 165 329-0 232 449*6 299 570-2 366 690*8 32 89-6 99 210*2 166 330-8 233 451-4 300 572*0 367 692-6 33 91*4 100 212-0 167 332 6 234 453-2 301 573*8 368 694*4 34 93*2 101 213*8 168 334*4 235 455-0 302 575*6 369 696-2 35 95*0 102 215-6 169 336*2 236 456-8 303 577-4 370 698*0 36 96-8 103 217*4 170 338*0 237 458-6 304 579*2 371 699-8 37 98*6 104 219*2 171 339-8 238 460*4 305 581*0 372 701*6 38 100*4 105 221*0 172 341-6 239 462*2 306 582-8 373 703-4 39 102*2 106 222-8 173 343*4 240 464*0 307 584*6 374 705-2 40 104*0 107 224*6 174 345-2 241 465*8 308 586*4 375 707-0 41 105-8 108 226-4 175 347-0 242 467*6 309 588-2 1 376 708*8 442 Tables, Etc. C. F. 42 107-6 43 109-4 44 111-2 45 113*0 46 114-8 47 116-6 48 118-4 49 120-2 50 122*0 51 123*8 52 125*6 53 127-4 54 129-2 55 131-0 56 00 CO H 57 134-6 58 136-4 59 138-2 60 140-0 61 141*8 62 143*6 63 145-4 64 147-2 65 148-0 66 150-8 67 152-6 C. F. 109 228-2 110 230-0 111 231-8 112 233*6 113 235-4 114 237-2 115 239-0 116 240-8 117 242-6 118 244-4 119 246*2 120 248-0 121 249-8 122 251-6 123 253*4 124 255*2 125 257*0 126 258-8 127 260-6 128 262 -4 129 264*2 130 266-0 131 267-8 132 269-6 133 271-4 134 273-2 C. F. 176 348*8 177 350*6 178 352-4 179 354-2 180 356-0 181 357-8 182 359-6 183 361-4 184 363-2 185 365-0 186 366*8 187 368-6 188 370-4 189 372-2 190 374-0 191 375-8 192 377-6 193 379-4 194 381-2 195 383-0 196 384-8 197 386*6 198 388-4 199 390-2 200 392-0 201 393-8 C- F. 243 469*4 244 471-2 245 473-0 246 474-8 247 476-6 248 478-4 249 480-2 250 482-0 251 483 8 252 485*6 253 487-4 254 489-2 255 491-0 256 492-8 257 494-6 258 496*4 259 498*2 260 500-0 261 501-8 2b2 503-6 263 505-4 264 507-2 265 509-0 266 510*8 267 512-6 268 514-4 C. F. 310 590-0 311 591 *8 312 593*6 313 595*4 314 597-2 315 599*0 316 600*8 317 602*6 318 604*4 319 606-2 320 608*0 321 609*8 322 611-6 323 613-4 324 615-2 325 617-0 326 618-8 327 620-6 328 622-4 329 624-2 330 626-0 331 627*8 332 629-6 333 631-4 334 633-2 335 635*0 C. F. 377 710-6 378 712-4- 379 714-2 380 716-0 381 717-8 382 719-6 383 721-4 384 723-2 385 725-0 386 726-8 387 728*6 388 730*4 389 732*2 390 734-0 391 735*8 392 737*6 393 739-4 394 741-2 395 743-0 396 744-8 397 746-6 398 748-4 399 750-2 400 752-0 450 842-0 500 932-0 Appendix. Introduction. Not only is the formation of soap from fats and alkali a true chemical process, and therefore best explained by reference to the fundamental principles of chemistry, but the numerous raw materials employed, and the various stages of manufacture also offer many opportunities for profitable as well as interesting chemical observation. In late years soap makers have more and more taken up the study of this science, and with so good results that whereas the manufacture of soap was once enshrouded in mysteries, the soap maker of to-day at least understands the reas¬ ons underlying the facts that come daily under his practical ob¬ servation. Formerly, attempts were numerous to improve the art of soap making by new processes, the impossibility of which would have been plain at once to every chemist; but in their stead chemistry has made possible improvements which, without this science, would undoubtedly never have been thought of. The manufacture of soda ash and caustic soda from salt, and the recovery of glycerin from spent lyes, are notable examples of this fact. It is undoubtedly possible to be a practical soap maker with¬ out understanding even the first principles of chemistry, but it is also safe to predict that every practical soap maker would be less dependent on chance and would acquire a much clearer knowl¬ edge of his calling by familiarizing himself with chemistry, at least sufficiently to thoroughly understand those principles on which soap making is based. The foregoing pages have been written with a view to cover the requirements of practical soap makers, whether they have any knowledge of chemistry or not, and it is not within the pro- 444 Appendix. vince of this book to teach the rudiments of that science. But many of the facts pointed out in these pages will acquire greater significance and be more distinctly understood by the reader when viewed in the light of the teachings of chemistry. Not only is this science of great use in aiding the practical manufacturer to properly understand his work, but it also gives him the means of conducting practical operations, and, in fact, his entire business to better advantage: It enables him to de¬ tect adulterations in the raw materials, to discover and remedy the causes of occasional irregularities in his work, to avoid waste, to work out improvements, and last, but not least, it places him in a position to judge intelligently of the practical value of new materials and methods. 4* 'f* 't* 'f' ^ Note 1: Alkalies are the oxides of the so-called “alkali metals,” these being the metals that oxidize readily in the air, are lighter than water, and decompose the latter at ordinary temperatures with the liberation of hydrogen and the simultaneous formation of their hydroxides. [In the case of ammonia (NH 3 ) it is con¬ sidered that, when dissolved in water, it forms the hydroxide N H 4 HO in which the radical “ammonium” (NH,) is of metallic character in its chemical behavior.] These alkalies are the strongest bases known and unite with water to form “hydrates,” i. e. the caustic alkalies. Alkaline Earths may be defined as oxides of certain metals (called the alkaline earth metals), namely of calcium, strontium, and barium; magnesium may also be included in the group, al¬ though it has very little of an alkaline character. They derive their name from the fact that they resemble on one hand the oxides of the alkali metals, and on the other hand arrange them¬ selves with the true earths. Note 2: Almost all fats and oils are “glycerides,” or ethers of glyce- rin. Glycerin is an alcohol, for the alcohols are those compounds that are formed when the radical HO is substituted for one or more atoms H in a compound of hydrogen and carbon; thus the hydrocarbon ethane, C 2 H 6 , forms the ordinary alcohol C 2 H 5 HO in the manner stated. Similarly the substitution of three atoms Appendix. 445 °f H by as many groups HO in the hydrocarbon C 3 H„ forms the alcohol glycerin, C 3 H 3 (HO) 3 . The alcohols therefore are the hy¬ drates of the alcoholic radicals. Some fish oils contain ether-like compounds of a different alcohol, Cetyl-alcohol; wool fat con¬ tains the ether of cholesterin. Ethers may be simple or com¬ pound, the simple ethers being- the oxides of the alcoholic radi¬ cals, formed by the action of acids on the alcohols, thus: C H 5 HO c 2 h 5 ) 5 1 o c 2 h 5 i u forms Ethyl hydrate = alcohol. Ethyl oxide = ether. The compound ethers are formed by the double decomposi¬ tion of an acid and an alcohol, as in the following example: O Ethyl Nitric Water Nitric hydrate acid ether From the action of fatty acids on glycerin in this manner the compound ethers, which constitute the fats and oils, are de¬ rived, thus: C 2 H 5 \ n NO, ) n _H ) n N0 2 \ H f ° + j C 2 H 5 j 3C 18 H 35 0 ) I C 3 H 5 ) ^_3H j q T (Ci 8 H 35 0) 3 ) ^ H|°+ H 3 i° 3 -Hf U C 3 H 5 i ° 3 Stearic acid Glycerin Water Stearin This reaction may be actually obtained by heating for 3b hours, in a closed tube, certain parts of glycerin and stearic acid Note 3: The organic acids may be considered as derived from the alcohols (as indeed occurs in making vinegar [—acetic acid], which belongs to the fatty acids—from alcohol), by replacing O for H 2 : C 2 H 6 0 : C,>HA « Alcohol Acetic acid Note 4: The formation of soap and separation of glycerin on boiling a fat with caustic lye is represented by the following equation: (C 18 H 35 0) 3 ) q _ 3C 18 H 35 0 I q , C 3 H 5 ( q C 3 H 5 j O^+^NaOH— Na f U + H 3 J Stearin Caustic soda Sodium stearate Glycerin (Soap) 446 Appendix. Note 5: The decomposition, by water, of neutral soap into a mix¬ ture of alkaline and of acid soap, may be illustrated by the fol¬ lowing - : 3(C 18 H 35 0 2 Na)+H0=C 18 H350. 2 Na0HNa+C 18 H3 5 0,NaC 18 H360 2 Note 6: The principal fatty acids are the following - : Found principally in: C 4 H s 0 2 .Butter. Ci 2 H 24 0 2 .Cocoanut oil. c 1( h 28 o 2 . C 16 H 32 0 2 .Lard, tallow, palm oil. C 18 H i6 0 2 .Lard, tallow. c 18 h 34 o. “ C ]6 H 26 0 2 .Linseed oil. Butyric acid Laurie acid Myristic acid Palmitic acid Stearic acid Oleic acid Linoleic acid Ricinoleic acid C 1S H 34 C >3 .Castor oil. Note 7: The influences at work in turning - fats rancid have been made a study by many eminent investigators, but no final con¬ clusion has been reached. It has been held—by Liebig and others—that the foreign admixtures, such as albumen, mucous, etc., in a fat acted as a kind of ferment; others considered that the impurities merely attract oxygen and yield it to the fats; ac¬ cording to another view (by Berthelot) moisture is the first cause of rancidity; and Virchow and others ascribe it to the action of certain micro-organisms. Ed. Ritsert, by a series of experiments, found that when the air is excluded , sterilized lard will not turn rancid, even if it contains moisture, and is subjected to sunlight. Nor did it become rancid when exposed to the air and the light excluded . When exposed to hath sunlight and air the lard turned distinctly rancid within a week, but no bacteria could be found in the fat. It may occur that micro-organisms are found in ran¬ cid fat, as in so many other substances, but when such organ¬ isms were introduced into sterilized lard and the latter exposed to the sun, it developed more free fatty acids and yet the micro¬ organisms died. It seems to be established by these trials that sunlight and air together are able to cause rancidity of fats, and that micro-organisms are not concerned in the change. Ferments also do not seem to take part in it, for sterilized fat that had Appendix. 447 been heated to a temperature at which all known ferments are killed, turned rancid after exposure to light and sterilized air or oxygen, F at freed from moisture turned even more rancid than fat charged with it, so that moisture does not appear to be so important a factor in the process as was supposed. Note 8: Sodium oxide and water combine according to the following formula to form caustic soda: Na 2 0+H 2 0=2Na0H, and according to the atomic weights (Na=23, 0=16, H=l) it follows that 62 parts NaO and 18 parts water, form 80 parts sodi¬ um hydrate. Note 9: The decomposition of soap by salts contained in hard water is shown by the following formula: 2C 18 H :!5 Na0. 2 +CaH 2 (C0 3 ) 2 =Ca(C 18 H 35 0 2 ) l +2NaHC0; { , Sodium Calcium Calcium Sodium stearate bicarbonate stearate bicarbonate Note 10: Caustic soda or lime are frequently employed to soften hard water when the hardness is caused by carbonates; the reaction which reduces the hardness is as follows: Ca H 2 (CO.t) 2 +Ca (OH ) 2 =2CaC0 3 +2 FLO, Calcium Calcium Calcium Water bicarbonate hydrate carbonate The bicarbonate of lime causing the hardness is by this re¬ action changed into the insoluble carbonate, which precipitates. Note 11: The reaction taking place in separating a potash soap by means of salt is a double decomposition, the hydrochloric acid of the salt combining with the potash, and the fatty acids combin¬ ing with the soda. When carbonate of potash is added to a soda soap, some potash soap and carbonate of soda is formed. Both changes are due to the fact that when both soda and potash are present, combined with two acids, the potash has a tendency to combine with the stronger acid. Hydrochloric acid is stronger than fatty acids, and these are stronger than carbonic acid. How¬ ever, when only fatty acids are present, and the soda and pot- 448 Appendix. ash are both caustic, they seem to combine with equal preference for the several fatty acids. Note 12: The formula for both, silvic and pinic acid is C 2() H 30 O,, they being- isomeric. Note 13: Soda ash and potash are made caustic by the action of quick¬ lime by the withdrawal of carbonic acid, as follows: Na 2 C0 3 + Ca (H0) 2 ==CaC0 3 +2Na HO: Carb. soda Calcium Calcium Caustic soda Hydrate Carbonate Note 14: The decomposition of fat by means of heat and water (steam) into fatty acids and glycerin (compare also Note 2) is effected according to the following formula: C 3 H 5 f Ua Hi U H 3 f Stearin Water Stearic acid Glycerin This reaction, it will be noticed, is very similar to that by which soap is formed when lye is employed instead of water, as explained in Note 4. Note 15: j Soda ash and soda crystals consist essentially of carbonate of soda. The soda ash is anhydrous, and may be of very vari¬ able degrees of purity; the crystals are obtained by crystallizing them out from a strong solution of soda ash in water and are much purer than the soda ash from which they are made, but the alkali in them is combined with water of crystallization. “Caustic soda ash” is a carbonate of soda containing a pro¬ portion (more or less) of caustic soda. Ordinary ash contains but little caustic. Crystallized soda contains about 63 per cent of water and 37 per cent of carbonate of soda. The impurities of soda ash made by the Leblanc process of alkali manufacture consist chiefly of sulphate of soda, silicate of soda, common salt, caustic soda, carbonate of lime, sand, iron, etc. The product of the Ammonia process is very much purer, and free from caustic soda. Appendix. 449 Note 16: Fats consist of carbon, hydrogen, and oxygen, in about the following- proportions (varying with the kind of fat): Carbon 78 parts, hydrogen 12 parts, oxygen 10 parts. Note 17: The crystals of sal soda formed by the process as described in the chapter devoted to that subject have the composition Na s COs+ 10H 2 O; in hot weather Na 2 C0 3 -{-8H 2 0 may form instead. Note 18: Carbonate of lime has the composition Ca C0 3 ; when burnt it becomes CaO; on adding water to the latter there forms the hydrate CaH 2 0 2 . Note 19: The reaction of caustic soda and ammonium chloride is ex¬ pressed as follows: NH 4 C1 -f NaOH = NaCl + NH 3 + ' 1I 2 0 Amm. chloride Caustic soda Sodium chloride Ammonia Water. In the case of ammonium sulphate the reaction is: 2(NH 4 )S0 4 +> 2NaOH = Na 2 S0 4 + 2NH 3 + 2H 2 0 Amm. sulphate Caustic soda Amm. sulphate Ammonia Water. Analogous reactions occur also with carbonate of soda in place of the caustic. Note 20: The development of oxygen from the reaction of acids on bi¬ carbonate of potash (or soda) is exemplified by the following: K 2 Cr 3 0 7 + 4H 2 S0 4 = K 2 S0 4 + Cr 3 (S0 4 ) 3 = 4 H 4 0+30 Pot. Bichromate Sulph. acid Pot. Sulph. Chr. alum Water Oxygen. . . ' INDEX. Adulteration of fats and oils. 35 Alcohol. 84 Alcohol test as to its origin. 413 Alkalies. 23, 72 Alkali required for saponification. 437 Almond oil. 66 Allspice oil. 320 Alum. 83 Ambergris. 321 Ambrette seed. 321 Anethol. 321 Anise Aldehyde. 321 Anise oil.;. 321 Antiseptic shaving soap. 370 Appendix. 443 Arrangement of factory. 87 Artificial colors and shades. 314 Artificially figged Soap. 247 Artificial oil sassafras.'. 321 Artificial oil wintergreen. 321 Aubepine. 322 Avoirdupois weight. 439 Balsams. 322 Bay oil. 322 Benzoin. 322 Bergamot oil. 322 Birch oil. 322 Bitter almond oil. 323 Bleaching cocoanut oil. 50 grease. 46 linseed oil. 62 palm oil. 53 rosin. 69 soap. 61 tallow.. • *. 43 452 Index. Page. Blue mottled. 229 Boiled-down soap....180, 211 Boiled shaving soap. 3(59 Boiling process.181, 249 Boiling down. 215, 221 Borax. 82 Borax tests for earthy impurities. 414 alum.. 414 carbonates and sulphates. 414 salt. 415 soda. 415 Bunching.188, 218 Cananga oil. 324 Caraway seed oil. 324 Caraway chaff oil. 324 Carbolic soap. 294 Carbolic soap. 375 Care of the dies. 353 Cassia oil. 324 Cassie oil. 324 Castor oil. 63 Causticizing alkali. 95 Caustic grades of Lye. 72, 74 Caustic soda required for making lye. 437 Cedar wood oil. 324 Chipper. 164 Chipping the soap. 307 Cinnamon oil. 325 Citron oil.,. 325 Citronella oil. 325 Civet. 325 Clove oil. 325 Cocoanut oil. 48 / Cocoanut oil soap filled with salt solution. 287 Cold made shaving soap. 368 Cold process.180, 269 Coloring. 284 Coloring soap. 228 Coloring and perfuming. 313 Coloring.;_ 313 Compounding perfume. 319 Connection with kettles. Ill Copaiba Balsam. 325 Corn oil.,.’. 65 Cottonseed oil. 57 _ Cotton Stearin. 60 Cottonseed foots. 60 Coumarin. ••••. 30(5 Index, Crown soap. Crutchers.. Crystal transparent soap. Cutters. Decomposition by graining-. Detergents, various.. Dies. Dill oil. Drying apparatus. Early method of milling. Effect of soap in washing. various fats on soap. various lyes on soap. water in washing. Eschweger. Eschweger III. Essential oils. Eucalyptus oil. Eugenol.'. Expansion of oils by heat *. Fats and Fatty acids. Fats and oils. Fennel.-. Figged soap. Filled cocoanut oil soap. Filling. Filling materials. Fish oil. Floating soap. Formation of soap... Formulas for various cold made soaps. .. F rames. Framing. Free fatty acids in fat. Fuller’s Earth. Fuller's fat. Gall soap. Gaultheria.. Geraniol. Geranium oil. German Mottled. Ginger grass oil. Glycerin. Glycerin and its recovery from waste lye Glycerin lime in. adulterated.. . amount of in waste lye. Glycerin soap. Page. . 243 . 116 . 364 .• 135 . 255 . 29 . 149 . 326 . 141 . 304 . 28 . 34 74, 76, 78, 227 .. 28 . 223 . 229 .. 415 . 326 . 326 . 438 .. 24, 31 . 419 . 326 . 245 . 287 . 283 . 79, 200, 201 . 64 .179, 264, 357 . 25 . 286 . 127 197, 207, 217 . 422 . 83 . 65 326 326 327 212 327 422 395 422 422 423 290 454 Index. Glycerin transparent soap... Graining. Grease. Guaiacum wood oil. Half boiling process. Half boiled shaving soap.... Half boiled tooth soap. Hand stamps. Hard soap. Hard water soap... .. Harness soap. Heliotropine. Horse fat. Imperial measure. Infusorial Earth. Jonone. Kettle connections. Kettles. Kuro-moji oil. Lanolin. Lanolin soap. Lard. Laundry soap. Laundry soaps. Laurie acid. Lavender... Lemon grass oil. Lemon oil. Lilacine. Lime. Lime oil... Linaloe oil. Linalool. Linoleic acid. Linseed oil... Lye. Lye apparatus. Lye tank. Mace oil. Marbled castile. Marbling. Margaric acid. Marjoram oil. Medical soap. Melissa oil. Melting trough. Metal polishing soap. Metric weights and measures Page. . 364 . 190 . 45 . 327 .181, 257 . 369 . 372 ... 162 . 381 . 179 . 374 . 327 . 66 . 439 . 83 . 327 . Ill . 101 . 327 . 63 . 291 . 47 . 137 . 291 . 33 . 327 . 329 . 328 . 329 . 85 . 329 .329 . 329 . 33 . 62 71, 73, 226, 237, 275, 277 . 95 . 89 . 329 . 219 . 284 . 33 . 330 . 387 . 330 . 98 . 374 . 438 Index. 455 Page Mill. 165 Milled soap. 182 Milled soaps. 303 Milled tooth soap. 372 Milling process. 307 Mineral soap stock.’. 82 Mirbane. 330 Mixing and saponification. 221 Modification of Eschweger. 232 Mosaic soap. 295 Musk. 330 Myrcia. 330 Myristic acid. 33 Natural color of soap.. 314 Nature of soap. 23 Neroli. 331 Nerolin. 331 Nigre. 201 Nutmeg oil. 331 Oenantkic ether. 331 Oleic acid. 6G, 213 Oleic acid. 33 Olibanum oil. 331 Olive oil. 56 Olive oil foots.•. 56 Opoponax oil. 331 Orange oil. 331 Origanum oil. 331 Orris root. 332 Orris root oil. 332 Palmarosa. 332 Palmitic acid. 33 Palm Kernel oil..... • 55 Palm oil. 51 Patchouly oil. 332 Peanut oil. 64 Peppermint oil.332 Perfumes for laundry soap. 340 (boiled) milled soap.• 345 cold-made soap. 341 Perfuming. 284 Perfuming.. 370 Perfuming . 319 Perfuming milled soap. 310 Peru Balsam. 333 Pennyroyal oil. 332 Pine needle oil. 333 Pinenta oil. 333 l 456 Index. Plodder. Potash. Powder mills.. Presses. Pressing the soap. Process of making cold made soap... Pumps. Pure cocoanut oil soap. Rancidity of fats and oils. Red mottled castile. Red oil.. Remelted soap. Remelters. Remelting soap. Rendering fats. Reunion. Rhodinol. Rhodium. Rose geranium. Rosemary oil. Rose oil. Rosewood oil.. Rosin. Rosin soap. Rosin soap.. Rue oil. Safety device for pressing. Safrol. Sage oil. Sal soda. Sal soda making. Sal soda tank. Salt. Salt water soap. Sand soap. Santal wood oil. Saponification... Sassafras oil. Scouring soaps. Scraps. Selection and preparation of perfumes Selection of stock and methods. Settled soap. Settling. Settling tank. Shaving soap. Shaving soap. Shaving soap. Page. . 166 . 77, 82, 227 . 170 . 142 . 351 . 289 . 112 . 286 . 35 . 375 . 66 . 183 . 116 . 299 . 38 . 327 . 333 . 333 . 333 . 333 . 333 . 334 . 68 . 292 .185, 264 . 334 . 160, 161 . 334 . 334 .82, 227 . 389 . 127 . 76, 227 . 376 . 373 . 334 41, 67, 186, 205, 213, 224 . 335 . 272 . 204 . 337 .:. 173 . 185 . 195 . 99 . 175 . 367 . 367 I If Index. 457 Silicates .80, 227, 258 Slabbers. 135 Soap, action of... 28 amount of fatty acids in. 424 antiseptic shaving. 370 blue mottled. 229 boiled. .. 131 boiled down.180, 211 boiled shaving. 3(59 carbolic. 294, 375 cocoanut oil filled with salt solution. 287 cold-made.180, 269 cold-made process. 239 cold-made shaving. 368 crown. 243 crystal transparent. 364 Eschweger.. 223 Eschweger III..<. 229 figged.245, 247 filled cocoanut oil. 287 filling. 425 floating.179. 357 floating. 357 formation of. 25 formulas for various cold-made. 286 free alkali. 426 from different stocks. 34 gall. 377 general remarks on boiling. 247 German mottled. 212 glycerin. 290 glycerin transparent. 364 glycern in. 427 half-boiled. 181 half-boiled. 257 cocoanut oil. 266 floating. 264 for milling. 262 mottled.... 263 rosin. 264 tar. 265 white. 261 half-boiled shaving. 369 half-boiled tooth. 372 hard. 381 hard water. 179 harness. 374 458 Index. Soap, lanolin. laundry. lye for cold-made. marbled castile. medicinal. metal polishing. milled. milled tooth. modified Eschweger. mosaic. nature of. natural color of. perfumes for laundry. cold-made. (boiled) milled. perfuming milled. pressing the. properties of soft. pure cocoanut oil. remelted. remelting. rosin. rosin in. salt water. sand. scouring. settled. shaving. soft. special. special properties of. stock. stock for milled. stock used. sugar in. sulphur. superfatted. surgical. tallow and cocoanut oil. tar. textile. toilet. tooth. transparent. transparent with sugar. rosin and sugar without alcohol. glycerin. Page. .... 291 173, 291 .... 74 .... 219 .... 378 .... 374 182, 303 . 372 .... 232 .... 295 .... 23 .... 314 .... 340 .... 341 .... 345 .310. .... 351 ... . 235 .... 286 .... 183 .... 299 185, 292 .... 426 .... 376 .... 373 .... 375 .... 182 175, 367 235, 381 .... 357 .... 179 .... 60 .... 305 .... 426 .... 426 .... 383 .... 382 .... 384 .... 287 293, 376 .... 176 .... 174 177, 370 179, 359 .... 365 .... 365 .... 366 .... 366 In dex. 459 Soap, transparent tilled with salts.... unsaponified fat in. utilizing scraps of cold. . water in. white. white boiled-down. white castile. white settled. yield of hard... Soap factor)'-. Soap stock. Soda and potash. Soft soap. Soft soap. Spearmint oil. Special properties of soap. Special soaps. . Spike. Star Anise oil. Starch. Steam Separator. Steam syphon. Stearic acid. Stock. Stock blower. Stock for milled soap. Purity of. temperature for mixing. Storax... Strengthening. Strunz’s lye apparatus .' Substances for obtaining perfumes.... Sulphur soap . Superfatted soaps. Surgical soap. Table of different thermometric scales Tables etc. Talc. Tallow. Tallow. Tallow and cocoanut oil soap. melting point of. titer test of. Tar. beech. juniper. pine. Tar in general. Page. . 366 . 425 . 294 . 424 . 275 . 220 . 208 . 205 . 251 . 87 . 60 . 427 . 235 . 381 . 335 . 179 . 357 . 335 . 335 .81, 200 . 170 . 94 . 32 . 273 . 99 . 305 . 273 . 299 . 335 194, 207, 220 . F .320 . 383 . 382 . 384 . 440 . 437 . 79 . 42 . 419 . 287 . 420 . 420 . 432 . 432 . 432 . 432 . 433 # 400 Index. Page. Tar oil. 335 Tar soap. 293 Tar soap. 370 Temperature of w’et steam. 438 Terpineol.:. 335 Testing sodium carbonate. 430 potassium . 430 caustic soda and potash. 430 soda. 431 Tests for adulterated fat.•. 37 strength of lye. 71 Textile soap .. 170 The simpler tests and examinations in the soap factory. 411 for water in it. 414 The thermometer. 439 Thyme oil.;. 335 Tincture of ambergris. 339 balsam of peru. 339 benzoin. 339 civet. 339 musk. 338 orris root. 340 Storax. 339 tolu. 340 vanilla.•. 340 Toilet soap. 174 Tolu balsam. 330 Tooth soap .*.. 177 Tooth soap . 370 Transparent soap.179, 359 Transparent soap with sugar. 305 rosin and sugar. 305 without alcohol. 300 glycerin.,. 300 filled with salts. 300 Tripoli. 83 Troy weight U. S. 439 Utilizing nigre. 203 Utilizing scraps. 204 Utilizing scraps of cold soaps. 294 Vanillin. 330 Verbena oil.'. 330 Vetiver oil. 336 Washing powder. 385 Waste lye. 250 Water in fats. 421 Water in soap... 20, 85 Water used for washing. 28 Index. 461 Page. White boiled-down soap. 220 White castile. 208 White settled soap.*. 205 White soap. 275 Wine measure U. S. 489 Wintergreen oil. 386 Wool Grease . 63 Yield of hard soap. 251 Ylang ylang. 337 ■ • •' I library of congress ii ii i ill ii 1 mill 0 033 266 717 JS . i * • • ' • * • • • • * • -fife m i"*f~ i , i * • ,. • • • * • ,• * ■ . .If f I % * I • 1 «r»i •• * • ■ '*<• ! ."V- f »|»i ’ W -»'* • ’ # *. • . . <• . . * . . . . ' • • t ... ’ » ' ' ' • • ' -f ‘ ‘ * t I.*'# .. • 4 / • < , \ , t ' /