Sip; STEVJLl N G AND FRANCINE CLAR1C ART INSTITUTE LIBRART A PRACTICAL TREATISE ON THE MANUFACTURE OF SOAP AND CANDLES: BASED UPON THE MOST RECENT EXPERIENCES IN THE SCIENCE AND THE PRACTICE; COMPRISING THE CHEMISTRY, THE RAW MATERIALS, THE MACHINERY AND UTENSILS, AND VARIOUS PROCESSES OF MANUFACTURE, INCLUDING A GREAT VARIETY OF FORMULAS. EDITED CHIEFLY FROM THE GERMAN OF Dr. C. DEITE, A. ENGELHARDT, Dr. C. SCHAEDLER, and OTHERS. WITH ADDITIONS AND LISTS OF AMERICAN PATENTS RELATING TO THESE SUBJECTS. BY WILLIAM T. BEANNT, EDITOR OF "A PRACTICAL TREATISE ON ANIMAL AND VEGETABLE FATS AND OILS ;" ONE OF THE EDITORS OF "THE TECHNO-CHEMICAL RECEIPT BOOK." ILLUSTRATED BY ONE HUNDRED AND SIXTY-THREE ENGRAVINGS. PHILADELPHIA: HENEY CAREY BAIRD & CO., INDUSTRIAL PUBLISHERS, BOOKSELLERS AND IMPORTERS, NO. 810 WALNUT STREET. LONDON: SAMPSON LOW, MARSTON, SEARLE & RIVINGTON, Limited, ST. duststan's house, fetter lane, fleet street. 1888. Copyright by HENRY CAREY BAIRI) & CO., 1888. Collins Printing Hocse, 705 Jayue Street. 3E J. 7uff£tFUs( PREFACE. The magnitude of the soap industry, the importance of the trade, and the enormous capital embarked in it, as well as the wonderful relation which it bears with regard to the most impor- tant links in the chain of chemical industry, are not often suffi- ciently estimated. The distinguished chemist, Justus von Liebig, in his " Familiar Letters on Chemistry," says: — " The quantity of soap consumed by a nation would be no inac- curate measure whereby to estimate its wealth and civilization. Political economists, indeed, will not give it this rank; but whether we regard it as joke or earnest, it is not the less true that, of two countries with an equal amount of population, we may declare with positive certainty that the wealthiest and most highly civilized is that which consumes the greatest weight of soap. This consump- tion does not subserve sensual gratification, nor depend upon fashion, but upon the feeling of the beauty, comfort, and welfare attendant upon cleanliness ; and a regard to this feeling is coinci- dent with wealth and civilization. The rich in the middle ages, who concealed a want of cleanliness in their clothes and persons under a profusion of costly scents and essences, were more luxu- rious than we are in eating and drinking, in apparel and horses; but how great is the difference between their days and our own, when a want of cleanliness is equivalent to insupportable misery and misfortune ?" It is, however, only in the most modern times that the soap manufacture has attained the extraordinary magnitude which now IV PREFACE. distinguishes this branch of trade. Various circumstances have contributed to produce it, the principal one, however, being the development of the manufacture of soda, which freed the soap industry from its dependence on the uncertain and limited supply of barilla and kelp, and caused it to make such strides as could not have been anticipated by the most sanguine. The manufacture of soap has, on the other hand, been a powerful stimulus to the pre- paration of soda and of the important secondary product, chloride of lime (bleaching powder), which are so intimately allied with almost all branches of the chemical art. Thus soap occupies one of the most important pages in the history of applied chemistry. The increase in the consumption of this article has led, moreover, to the discovery of new materials for its production ; it has opened new channels to commerce, and thus it has become the means as well as the mark of civilization. Almost simultaneously with the employment of soda, the oils of the cocoanut and the palm have been introduced into the manufacture of soap, and there can be no doubt that the development of the trade in palm-oil has largely contributed to the abolition of the iniquitous slave trade on the west coast of Africa ; slavery invariably passing towards extinction, with a diversification of industries, no matter how humble and small the development of those industries. There is scarcely another industry which can show as many improvements, inventions, and novelties during the last ten years as the manufacture of soap, and yet, though there is no lack of good literature, there is not a book in the English language which treats the subject so fully as to answer all the demands and require- ments of modern times. To supply this want is the object aimed at in the preparation of this volume. It is chiefly based upon three recent German works, viz., Handbuch der Seifenfabrikation, edited by Dr. C. Deite; Handbuch der pracktischen Seifenfabrikation, by Alwin Engel- hardt, and Die Technologie der Fette und Oele, by Dr. Karl Schaedler. These works are the results of many years of prac- PREFACE. V tical experience, and are by men of acknowledged authority. The volume edited by Dr. Deite consists of contributions by various expert soap-boilers, giving each the method of fabrication in a spe- cial branch of the industry. A. Engelhardt's work contains many processes of manufacture and formulas which, being the result of years of active labor as manager and proprietor of large soap- works, and having been thoroughly tested, can be confidently re- commended to every soap-boiler. To Dr. Schaedler's work the editor of this volume is indebted for much of the matter relating to the raw materials, the preparation of fatty acids, and the manu- facture of candles. In order to make the present treatise as complete and reliable as possible, much time and care have been devoted to the gathering of information from all available and widely-scattered sources; and the editor takes pleasure in acknowledging his indebtedness to the work on the same subject by R. S. Christiani, published by the publishers of the present volume; to the writings of W. L. Car- penter, A. Watt, C. R. A. Wright, C. H. Schmidt, and many others; also to Dr. William H. Seaman, of the United States Patent Office, for Lists of Patents relating to the subjects treated of in the volume. WILLIAM T. BRANNT. Philadelphia, May 5, 1888. Digitized by the Internet Archive in 2012 with funding from Sterling and Francine Clark Art Institute Library http://archive.org/details/practicaltreatisOObran CONTENTS. PART I. MANUFACTURE OP SOAP. CHAPTER I. HISTORY OF THE MANUFACTURE OF SOAP. PAGE No mention of soap before the Christian era ; Vegetable and mineral lyes referred to in the Old Testament ; Cleansing of clothes in Homer's time ; Detergents used in time of Paulus JEg'ma ; Fuller's earth the principal agent for washing in ancient times ; The fuller's art due to Nicias, son of Hermais ; Importance of the Roman fullers (fullones) 17 Use of fuller's earth in England ; Legal restriction against its exporta- tion ; Pliny's statement of the use and manufacture of soap by the Gauls ; Invention of soap claimed for the Phoenicians ; Supposition regarding first attempts at soap making 5 Use of a mixture of oil and wood ash as a salve for cutaneous diseases ; Leon Droux's description of the soap made by the Cabyles in Algiers . . . . .18 Use of the soap of Algiers by the Arabs as a salve and for washing wool to be worked into tissues ; First mention of soap as a detergent ; Soap trade from the ninth to the seventeenth century in Marseilles, Venice, Savona, and Genoa ; Monopoly granted to a soap company in England in 1622; Summons before the Star-Chamber of soap- boilers for infringing the royal patent 5 Conditions imposed upon the London soap-boilers for privilege of carrying on the business ; French soap monopoly in the seventeenth century . . . . .19 French legislation to prevent adulterations of soap in 1688; German soap trade in the early centuries ; Its present condition ; High repu- tation of German soft soap for manufacturing and household pur- poses ; Condition of soap industry in the United States ... 20 Great improvement in soap manufacture after Leblanc's discovery of making soda from common salt ; Leblanc's troubles and untimely death ; Valuable services of Chevreul in raising soap-making to its present position as a truly scientific art . . . . . .21 Vlll CONTENTS. PAGE Great addition to the variety of soaps by introduction of new fats and oils ; Value of caustic soda to the soap-boiler ; Politico-economic view of soap . . . . < . . . . .22 CHAPTER II. RAW MATERIALS USED IN THE MANUFACTURE OF SOAP. Ingredients and general preparation of the ordinary soaps of commerce ; Fats and their constitution ; Common properties of vegetable and animal fats ; Characteristics of absolutely pure fats and of com- mercial products; Characteristics of solid fats and of train-oils . 23 Division of fats according to their consistency; Melting-points of solid fats ; Firm consistency of liquid fats at a low temperature ; Expan- sion of oils by heat according to Preisser ; Change in fats by expo- sure to the atmosphere ; Characteristics of "drying and non-drying oils;" Insolubility of pure fats in cold alcohol; Solubility and acid reaction of rancid fats ; Chemical constitution of fats ... 24 Table showing the elementary composition of some fats ; Natural fats are not simple chemical combinations, but mixtures of such ; Dis- covery of glycerin by Scheele in 1779; Elucidation of the nature of fats by Chevreul .......... 25 Confirmation and improvement of Chevreul' s examinations of fats by Berthelot and Heintz ; Constituents of glycerides ; Old and modern chemical ideas of glycerin ; Chemical formula of monoglyceride, diglyceride, and of triglyceride ; Artificial preparation of glycerides 26 Preparation of monostearin, distearin, and tristearin, and their chemi- cal formulas ; Chemical formula of cetyl alcohol, of cholesterin ; Fatty acids ; Division into four groups with their chemical symbols ; Acetic series of acids occurring in fats ; Butyric, caproic, caprylic, capric, lauric, myristic, palmitic, stearic, arachidic, behenic, cerotic, and theobromic acids with their chemical symbols ; Volatile fatty acids and their characteristics . . . . . . . .27 Lauric acid, its crystallization, specific gravity, and melting-point; Palmitic acid, its melting-point, specific gravity, solidification, solu- bility, and acid reaction ........ 28 Stearic acid, crystallization, solidification, distillation, specific gravity, and solubility ; Salts of stearic acid and other non-volatile fatty acids ; General characteristics of alkaline salts ; Separation of the stearat.es from their solutions . . . . . . . . .29 Potassium stearate, its crystallization and solution; Sodium stearate; Conversion of ammonium stearate into the acid salt ; Obtaining the other salts of stearic acid by precipitation from aqueous solutions ; Important facts in the quantitative determination of stearic and palmitic acids ; Margaric acid ; Behavior of stearic and palmitic CONTENTS. IX PAGE acids in the manufacture of stearin candles ; Table of the behavior of mixtures of stearic and palmitic acids . . . . .30 Advantages of using mixed fatty acids over pure fatty acids in the manufacture of candles ; Acids of the oleic series found in fats with their chemical formulas ; Oleic acid, its properties and characteristics 31 Sodium oleate, crystallization, and solution ; Potassium salt, comparison of with sodium salt ; Description of barium salt ; Lead oleate . 32 Acids of the third group found in fats; Linoleic acid, its specific gravity and chemical reaction ; Characteristics of the barium and calcium salts of linoleic acid ; Acids of the fourth group ; Ricinoleic acid, specific gravity and chemical properties ; Titrations of free fatty acids ; Prep- aration of phenol-phthalein ; Alcohols of the fatty group . . 33 Pure glycerin, symbol, specific gravity, and chemical properties ; Cetyl alcohol, symbol, melting and boiling points, and solubility ; Chole- sterin, specific gravity, melting point, solubility ; Glycerides . . 34 Tristearin (stearin), symbol and chemical properties; Tripalmitin (palmitin), symbol and chemical properties ; Laurin (laurostearin), symbol and chemical properties ; Triolein (olein), symbol and chem- ical properties . . . . . . . . . .35 Solidity of fats according to the proportional quantities of stearin, palmitin, and olein ; Saponification of fats, former and modern under- standing of the term . . . . . . . . .36 Action of ammonia upon fats ; Glycerides in the manufacture of soap and candles and fabrication of plasters ; Manufacture of stearic acid . . . . . . 37 First introduction of lime for alkalies in saponification of fats, and of sulphuric acid for the decomposition of lime-soap; Runge's patent for saponification of fats by high pressure; Milly's patent of the "Autoclave;" Distillation of fats ; Splitting neutral fats by means of water at a high temperature ; Treatment of a neutral fat with anhy-* drous oxide of zinc . " . . . . ... . .38 Saponification of the fats by lime under ordinary atmospheric pressure ;, Apparatus illustrated and described . . . . 39 Prevention of the spreading of noxious odors formed by saponification with lime ; Closed apparatus of Delapchier ..... 40 Closed apparatus of Leon Droux ; Decomposition of the calcium sebate ; Complete purification of the melted fatty acids from lime . . 41 Frame for congealing fatty acids, illustrated and described . . .42 Horizontal hydraulic press, with plates to be heated with steam or hot water, illustrated and described ........ 44 Advantageous use of barium hydrate in stearin manufactories ; Saponi- fication with alumina ; Natrona refined saponifier .... 45 Cooling apparatus for stearic acid factories, illustrated and; described . 46 X CONTENTS. PAGE Weise's advantageous method of freeing stearic acid from oleic acid; Saponification with little lime, assisted with pressure ; DeMilly's autoclave, illustrated and described ...... 48 Use of sodium oxide in connection with lime for saponification ; James H. Clinton's patent for extracting glycerin from fatty substances de- scribed ............ 50 Saponification of the fats with sulphuric acid and subsequent distillation of the fatty acids ; " Fremy's" acids ; English and French claims to the discovery of the sulphuric acid process ; Variation in decomposi- tion of fats ........... 52 Class of fats used in the sulphuric acid process ; Process of saponification 53 Hughes's continuously working apparatus for decomposing fats with little acid, illustrated and described ...... 54 Decomposing the sulpho-acids after the saponification is completed . 55 Elevation in the melting point of fatty substances after treatment by the Hughes process ; Injurious results from distilling fatty substances over an open fire .......... 56 Knab's continuously working distilling apparatus for fatty acids, illus- trated and described . . . . . . . . .57 Schattenbach's apparatus for distilling fatty acids, illustrated and de- scribed ............ 58 Tribouillet's distilling apparatus for fatty acids, illustrated and de- scribed ............ 59 Variation of the melting points of fatty substances during the process of distillation . . . . . . . . . .62 Yield of products of distillation from fats ; Decomposition of the fats by water ; By high pressure and increased temperature ; Danger of explosion by escape of volatile fatty acids in the process ; Investiga- tions of Appert (1825) and Manicler (1826) ; Processes of Tilgh- man (1854) and of Melsens ; Apparatus of Payen & Wilson . . 63 Wright & Fouche's distilling apparatus described ; Melsens' s use of a Papin's digester ; Decomposition (saponification) of the fats by means of superheated steam ; Practice at Price's Candle Co., Batter- sea, England ; Wilson distilling apparatus, illustrated and described . 64 Glycerin as obtained in the stearin factories . . . . .65 Process of removing contaminations found in crude glycerin ; Obtaining chemically pure glycerin . . . . . . .66 Tests for chemically pure glycerin ; Employment of glycerin in many industries ; Soaps ; General condition of the ordinary soaps of com- merce ; Peculiar behavior towards water; Knapp's experiment of suspending a piece of soap just below the level of cold water . . 67 Opinions of chemists in regard to processes which take place in treating soap with cold water; Neutral and basic salts obtained by the saponi- fication of fats .......... 68 CONTENTS. XI PAGE Rotondi's experiments with castile soap ...... 69 Rotondi's conclusions from his experiments; Rotondi's experiments of the action of water upon soap without dialysis . . . . 70 Decomposition of neutral soaps by water ; Solubility of basic and of acid soaps . . • . . . . . . . . .71 Phenomena accompanying the evaporation of water from soap solutions ; Unequal affinity of soaps for water . . . . . .72 Atmospheric influence on dry potash soaps and on moist soda soaps ; Absorption of water by sodium stearate, potassium stearate, and potassium oleate on being exposed some time to the air ; Character- istics of the hard mass congealed from soap solutions ; Behavior of soaps towards water in presence of other bodies having great affinity for water ; Results from mixing solutions of soap and of common salt . 73 Decomposition of potash soaps by sodium salts ; Chevreul's theory of the detergent properties not sustained ...... 74 Knapp's and Rotondi's theories of the detergent action of soaps ; Pro- fessor Jevon's explanation of the detergent powers of soap . . 75 CHAPTER III. OCCURRENCE AND MANNER OP OBTAINING AND PURIFYING FATS AND EAT OILS. Occurrence and manner of gaining fats and oils ; Purifying and refining fats and oils ........... 76 Refining oils for illuminating purposes . . . . . .77 Classification ; Refining oil for lubricating purposes ; Bleaching of oils ■ and fats ........... 78 Bleaching linseed and cotton-seed oil in soap factories by use of potash lye; Bleaching with sulphurous acid ; ..... 79 Bleaching with calcium chloride ; With potassium permanganate in con- nection with sulphuric acid; With potassium bichromate; Watt's process to regain the potassium chromate . . . . .80 Peroxide of hydrogen and animal charcoal as bleaching agents for oils . 81 CHAPTER IY. EXAMINATION OF FATS AND FAT OILS. Problems presented in the examination of fats and fat oils ; Organo- leptic method ; Physical methods . . . . . . .82 Cohesion of oils; Viscosity ; Importance of specific gravity in testing oils : Instruments for determining the specific gravity of fixed oils ; Standard normal temperature of the instruments in England and on Xll CONTENTS. PAGE the Continent ; Rule for bringing the actual to the normal tempera- ture for measuring density by the oleometer . . . .83 Lefebvre's oleometer, illustrated and described; Imperfect results from oleometer tests .......... 84 Methods for determining melting points of fats ; Julius Lowe's appa- ratus for determining melting points, illustrated and described . 85 Determination of the congealing point of a fat ; Valenta's method by solution in glacial acetic acid ; Results obtained by his experiments . 87 Table of results obtained from solution of equal parts of various fats in glacial acetic acid ; Rousseau's method of testing oil by their electrical conductibility .......... 88 Chemical methods for examination of fats ; Elaidin test ; Increase of temperature arising from the admixture of concentrated sulphuric acid with the fatty oils the only test giving reliable results ; Table of results obtained by Maumen6's test ...... 89 Koettstorfer's method of determining the saponification equivalents; Valenta's plan of examining fats by Koettstorfer's method . . 90 Valenta's division of oils into three groups; Hiibl's iodine process for testing fats ........... 91 Combination of non-saturated acids with iodine ; Satisfactory test by a solution of iodine and mercuric chloride . . . . . .92 Table of the iodine degree determined in oils ..... 93 Mailho's color test; Schneider's test for adulteration with colza; The tables of Th. Chateau and C. Calvert 94 Color reactions of Chateau ; Preparation and use of calcium disulphide ; Oils giving permanent and those giving transient gold color ; Zinc chloride ; Its coloring effect upon oils ...... 95 Sulphuric acid, shades produced upon oils by ; Stannic chloride, color effects produced by ......... 96 Syrupy phosphoric acid, color effects of . . . . .97 Mercuric nitrate, preparation of and color effects produced by . . 98 Mercuric nitrate, oils effervescing when treated by ; Crace-Calvert's method ............ 99 Table of reactions of oils according to Crace-Calvert . . . .101 The foreign admixtures in fats or oils, determination of; Thompson's method of detecting adulterations with cheaper oils; Finkener's pro- cess ............ 102 Non-saponifiable residue found in commercial oils .... 103 Finkener's test of quantity of non-saponifiable oil by determination of alkali required for saponification ; Potash solution for testing the non-saponifiable oil in a fat . . . . . . . .104 Detection of resin in fats ; Detection of free fatty acids ; Quantitative determination of fatty acids . . . . . . . .105 Determining the quantity of glycerin in a fat . . . . . 10.6 CONTENTS. Xlll PAGE Determination of glycerin by the process of Fox, Benedikt, and Zsig- mondi . . . . . . . . . . . .107 Braun's method of detecting carbon bisulphide in an oil obtained by extraction . . . . . . . . . . .108 CHAPTER V. FATS, FAT OILS, FATTY ACIDS, AND RESIN USED IN THE FABRICATION OF SOAP. Fats of animal origin ; Tallows ; Beef tallow ; Mutton tallow ; Ren- dering of crude tallow ; Dry and wet process of rendering . . 109 Dry rendering ; Greaves or cracklings and their uses ; Rendering by steam . . . . . .. . . . . .110 Mechanical and chemical contrivances for destroying the cells envelop- ing the fat . . . . . . . . . . .111 Attempts made to render inocuous the fetid odors developed in render- ing ; Vohl's apparatus to avoid offensive odors arising from rendering over an open fire, illustrated and described . . . . .112 Lockwood & Everett's steam rendering apparatus, illustrated and de- scribed . . . . . . . . . . . .114 Manufacture of Margarin ; Oleomargarin ; Tallow-oil ; Commercial tallow, refining and bleaching . . . . . . .116 Characteristics of pure tallow ; Iodine degrees of tallow and of fatty acid, separated from tallow, according to Hlibl, Demski, and Mo- rawski ; Detection of adulterants generally found in commercial tallow . . . . . . . . . . .117 Saponification of tallow . . . . . . . . .118 Composition and treatment of lard ; Adulterations of lard . . .119 Horse-fat, characteristics and treatment of . . . . . .120 Bone- fat, characteristics and treatment of . . . . . .121 Wool-fat, glue-fat, neat's-foot oil, characteristics and treatment of .123 Fish-oils and train-oils, characteristics, adulteration, and purification of 124 Spermaceti . . . . . . . . . . .125 Fats and oils of vegetable origin . . . . . . .125 Cocoanut-oil, source of supply and description of . . . .125 Cocoanut-oil, characteristics, composition, and saponification equivalent ; Iodine degree of ; Action of cocoanut-oil in saponification . . 126 Saponification of cocoanut-oil in the cold way ; Cochin- China oil, Cey- lon-oil, and Coprah-oil . . . . . . . . .127 Palm-oil, source of supply, description, melting point, saponification equivalent, characteristic features of, iodine degree, composition, etc. 128 Manufacture of white soap from palm-oil ; Process of bleaching palm- oil by heat . .129 Bleaching palm-oil by heat and air, and by means of chemical agents . 130 XIV CONTENTS. PAGE Variations of quality in commercial palm-oil ..... 131 Table of variation of the different palm-oils ; Obtaining palm-oil from the sediment formed by storage of large quantities ; Adulterations and substitutes for palm-oil '. . . . . . . . 132 Saponification of crude or bleached palm-oil ; Advantages of palm-oil in the manufacture of toilet soaps ....... 133 Palm-kernel oil; Schneider's apparatus for purification of, illustrated and described . . . . . . . . . .134 Palm-kernel oil, constituents of, melting point, saponification equivalent, iodine degree of . . . . . . . . .136 Injurious results from extracting palm-kernel oil by impure carbon bi- sulphide ; Detection of carbon bisulphide in extracted oil ; Shea butter, galam butter, or bambuk butter ; Mahwa butter, illoopa-oil or bassia-oil . . . . . . . . . . .137 Piney-tallow, vegetable-tallow, or vateria-fat ; Chinese tallow ; Not serviceable in its pure condition in the manufacture of candles and soap ............ 138 Advantage of mixing Chinese tallow with other tallows ; Commercial Chinese tallow ; Vegetable-tallow from Borneo . . . .139 Cocoa-butter, characteristics of . . . . . . . . 140 Recognition of genuine cocoa-butter; Principal adulterations of; dika- oil, or wild mango-oil ; Expressed oil of nutmeg, butter of nutmeg, or oil of mace, characteristics of ....... 141 Expressed oil of nutmeg, principal adulterants and means of detecting them; Becuiba tallow; Otoba butter; Virola tallow; Olive oil . 142 Olive-kernel oil ; Sulphur-oil, methods for bleaching it 143 Oils generally mixed with olive-oil in the manufacture of soap ; Char- acteristics of pure olive-oil ; Solution of olive-kernel oil . . . 144 Sesame-oil, manufacture and characteristics of; Its use in the manu- facture of soap ; Saponification of ....... 145 Peanut- or ground-nut oil, preparation of, characteristics of, and use in the manufacture of soap ......... 146 Elaidin soap, manufacture of, from peanut-oil ; Castor-oil, preparation and characteristics of ; Saponification of . . . . . .147 Cotton-seed oil, preparation and refining of .... . 148 Characteristics of refined cotton-seed oil ; Use of the crude and of the refined oil in the United States ; Saponification of . . .149 Use of refined cotton-seed in Europe, in the manufacture of soap ; Cot- ton-seed oil in soft soaps ........ 150 Cotton-stearin, or vegetable-stearin, preparation and characteristics of; Almond-oil, characteristics of . . . . . . .151 Linseed-oil, preparation and characteristics of; Tests for its adultera- tion; Use of in Germany in soap-making ..... 152 CONTENTS. XV PAGE Potash-soap from pure linseed-oil ; saponification of linseed-oil ; Soda soaps from linseed-oil ; Soap from linseed- and palm-kernel oil . 153 Preparation of soap from linseed-oil, bone-fat, and palm-kernel oil ; Pure soaps from linseed-oil ; Resin soaps with the assistance of lin- seed-oil ; Cameline-oil, or German sesame-oil, specific gravity and characteristics of; Niger-oil, specific gravity and characteristics of 154 Madi-oil, specific gravity and characteristics of; Soaps from, with soda- lye ; Hemp-seed oil, specific gravity and characteristics of; Sun- flower-oil, specific gravity and characteristics of; Its use in Russia as a table oil, and in the manufacture of varnish and soap . . .155 Poppy-seed oil, specific gravity, characteristics, and principal uses ; Colza-oil, specific gravity, characteristics, and uses of . . .156 Utilization of sedimentary oils ; Fatty acids and resin . . . 157 Use of fatty acids in the fabrication of soap ; Fuller's fat ; Fatty acids from the saponification of neutral fats ; Rapole'in . . . .158 Oleic- acid, preparation of; Distinction between saponified and distilled oleic-acid . . . . . . . . . . .159 Process of acidy saponification; Bolley and Bergmann's investigations of oleic-acid . . . . . , ,. . . . .160 Best means of examining oleic-acid ....... 161 Uses of oleic-acid ; " Soft fat" or " margarin ;" Fuller's fat ; Process of recovering it .• . . . . . . . . .162 Resin or colophony, sources of supply ; Boiled turpentine . . .164 Virgin turpentine; Window-glass turpentine; Window-glass resin; Yellow-dip turpentine; Common resin, characteristics and uses of . 165 Resin soaps . . . . . . . . . . .166 CHAPTER VI. ALKALIES. Designation of the term ; Formation of caustic alkalies ; Conversion of alkaline carbonates into alkaline hydrates . . . . .170 Soda; Natural soda; Geographical distribution of ; Latroni ; Trona ; Urao ; Soda deposits in the United States . . . . .171 Great Salt Lake, Utah ; Soda lakes near Ragtown, Nevada ; Mono and Owen's lakes, California; Summer and Abert lakes, Oregon; Table of the composition of their waters . . . . . .172 Estimation of the contents of Mono and Owen's lake . . . .173 Alkali industry of the far West ; Soda in the great Hungarian plain ; Szeks6 from the sand of the Theiss plain ; Sources of commercial soda ; Barilla . . . . . . . . . .174 Alicante soda ; Vegetable soda of Southern France ; Purification of vegetable soda ; Artificial soda . . . . . . .175 XVI CONTENTS. PAGE Leblanc's method of manufacturing soda; Preparation of sodium sul- phate . . . . . . . . . . . .176 Lixiviation of crude soda ; Shanks' s apparatus ; Carbonization for re- moving soda combinations from lye ; Calcining . . . .177 Ammonia process of converting common salt into soda ; Solvay's pro- cess . . . . . . . . . . . .178 Soda obtained from cryolite of Greenland . . . . .179 Crystallized soda, preparation of . . . . . . .180 Caustic soda, preparation of . . . . . . . .181 Commercial valuation of soda ; English, French, and German systems of valuation . . . . . . . . . . .184 Table of comparative valuations of soda . . . . . .186 Potash ; Constituents of commercial potash ; Potash from wood ashes ; Separating the soluble from the insoluble salts ; Lixiviating, bleach- ing or washing the ashes . . . . . . . .187 Evaporation of the lyes ......... 188 Red- American potash or stone-ash ; Potash from the carbonized resi- due of beet-root molasses. ........ 189 Composition of the carbonized residues from the distillation of beet- root molasses ; Potash from wool-sweat (suint) . . . .190 Potash from potassium sulphate . . . . . . . .191 Caustic potash . . . . . . . . . . .192 CHAPTER VII. TESTING OF SODA AND POTASH. Alkalimetry 194 Chemical law of combinations of bodies ; Gravimetric analysis, volu- metric analysis ; Preparation of test liquids or normal solutions, illustrated and described . . . . . . . .195 Testing solutions with litmus . . . . . . . .199 To bring commercial sulphuric acid to the test standard . . . 200 Behavior of solution of oxalic-acid towards alkalies ; Preparation of a normal caustic-soda solution ........ 201 Testing the value of alkalies to the soap-maker ..... 202 Determination of caustic-soda or caustic-potash in a soda-lye ; Deter- mination of the value of soda or potash . . . . . . 203 Examination of potash by volumetric analysis ..... 204 Normal acid solutions, normal alkaline solutions ; Manner of taking- samples for analysis ......... 205 Instrument for taking samples from barrels, illustrated and described . 206 CONTENTS. XV11 CHAPTER Till. AUXILIARY RAW MATERIALS. PAGE Water, revolution and chemical composition ..... 208 Soft and hard waters, determination of ..... 209 Test for degree of hardness in water ; Preparation of a soap solution to the proper test standard ; Table of the lime, and hardness of water in a soap solution ......... 210 Total, temporary, and permanent hardness of water . . . • 211 Comparative measures of hardness of water in England, Germany, and France ; Consumption of soap in London ; Injurious results from washing with hard water ; Simple remedy for hard water . . 212 Purifying turbid and impure water ; Simple methods for testing the purity of water ; Test for the presence of copper, carbonic acid, com- binations of sulphur, dissolved pure lime, and sulphate of lime . 213 Tests for alkalies and alkaline earths, iron, magnesia, free acids ; Lime, characteristics of; Basic principle of lime-burning . . . .214 Overburnt lime ; Fat lime ; Poor lime ; Pure lime ; Slaking lime ; Result of burnt lime exposed to the air ; Comparative solubility of lime in cold and in hot water ; To protect lime from access of atmo- spheric air . . . . . . . . . . .215 Determining the value of lime in the manufacture of soap ; Common salt, properties, localities, and characteristics; Table of analyses of rock-salt . . . . . . . . . . .216 Cause of the reports heard in the so-called detonating salt ; Constitu- ents and admixtures of the salt of commerce ; solution of salt in hot and cold water ; solution of sodium chloride in water; Table of the specific gravity in various salt solutions . . . . . .217 Importance of pure salt in soap-boiling ; Refining and purifying salt ; Soluble glass or water-glass ; Silicate of soda ; Silicate of potash . 218 Preparation of soluble glass . . . . . . . .219 CHAPTER IX. LYES. Preparation of lyes . . . . . . . . . . 220 Apparatus for dissolving caustic soda, illustrated and described . .221 Preparation of lyes from the carbonates of the alkalies ; Chemical combinations formed in causticizing the carbonates of the alkalies by means of burnt lime ......... 222 Undesirable results produced by concentrated caustic soda or caustic lye upon carbonates of the alkalies ; Best and quickest method of effecting causticity ; Theoretical proportions for causticizing potash B XV111 CONTENTS. PAGE and soda ; Larger amount needed in practical working ; Tanks for the preparation of lyes from the carbonates of the alkalies, illus- trated and described ......... 223 Charles Tennant & Co.'s directions for preparation of lye . . . 224 Causticizing in factories worked by steam ...... 225 Siphon for drawing off the clear lye, illustrated and described . . 226 Advantage of the lye prepared by the hot process ; Disadvantage of the cold process . . . . . . . . . .227 Lye for paste-soaps ; Natrona refined saponifier for saponification ; Preparation of lye from wood-ashes ...... 228 Testing the lyes; Table for the comparison of Baum6's degrees with those of Twaddle, with specific gravities and statement of the per- centage in soda and potash lyes at 59° F. '...'. . 229 Table giving the content of solutions of soda and potash according to degrees Baume in kilogrammes at 59° F. ..... 232 Table showing the yield of milk of lime, in degrees Baume, from 1 kilogramme of caustic lime, according to Edward Mategcek . . 233 Table of content, of caustic lime in milk of lime, according to Edward Mategcek ; Causticizing potash and soda with pure caustic lime . 234 Calculations for supplying the deficiency of caustic lime in causticizing potash and soda .......... 235 Table for soda and lime calculations ; Table for potash and lime calcu- lations ; To causticize a solution of soda or potash of unknown strength 236 Table showing the percentage of oxides and hydroxides in caustic soda and caustic potash lyes, with the corresponding specific gravities and aerometer degrees of Baum6 and Twaddle at 59° F. 238 Table giving the content of soda and potash lye in kilogrammes ac- cording to degrees Baum6 at 59° F. ..... . 240 To test the content of caustic alkalies and alkaline carbonates in a soda lye 241 To test a potash lye . . . . . . . . . .242 CHAPTER X. MACHINES AND UTENSILS FOR THE MANUFACTURE OF SOAP. Kettles, illustrated and described . . . . . . . 243 Heating the kettles by steam ........ 246 Steam kettles, illustrated and described . . . . . .247 Apparatus for heating with steam, combined with a mechanical stirrer, illustrated and described ........ 250 Apparatus for boiling with superheated steam, illustrated and described 251 Apparatus to prevent the contents of the kettle from rising and boiling over during the process of saponification, illustrated and described 253 CONTENTS. XIX PAGE Doll's special mixing machine, illustrated and described . . . 254 Soap-frames ; Frames of wood . . . . . . . .255 Frame of five sections ready for receiving the soap-paste, illustrated and described .......... 256 Frames of iron ; Iron soap-frame, illustrated and described . .257 Mattress-covering to prevent too rapid a cooling in the soap-frame, illustrated and described ........ 258 Frame provided with an arrangement for draining off and discharging the sub-lye, illustrated and described ; Bottom of frame, illustrated and described .......... 259 Whitaker's patent soap-frame, illustrated and described ; Soap-pumps ; Hersey's patent rotary soap-pump, illustrated and described . .260 Pump adapted for small factories, illustrated and described ; Soap- cutting machines . . . . . . . . . .263 Cutting a soap-block, illustrated and described ; KrulPs soap-cutter, illustrated and described ........ 264 Dopp & Son's iron soap-cutting frames, illustrated and described . 265 Slabbing and barring machine, illustrated and described . . .268 Caking machine, illustrated and described . . . . .269 Slabbing machine invented and made by A. W. Houchin, illustrated and described .......... 270 Soap planes ; Soap plane, illustrated and described .... 272 Soap-planing machines, illustrated and described ; Crutching machines ; Strunz's crutching machine, illustrated and described . . . 273 The jacket crutching machine, illustrated and described . . . 276 Minor implements ; Crutch, bucket, dipper, illustrated; General plans of soap factories ; General plan of a soap factory working with an open fire, illustrated and described . . . . . . .278 General plan of a soap factory with the use of steam, illustrated and described ........... 280 Ground-plan of a soap factory with the use of superheated steam, illus- trated and described ......... 281 Drying rooms . . . . . . . . . .282 Drying room heated with hot air, illustrated and described . . 283 CHAPTER XL- fabrication OF SOAPS. Division of soaps ; Hard or soda-soaps ; Soft or potash-soaps ; Curd or grain-soaps ; Paste-soaps ; Half-grain soaps (German Eschweg-soap) 285 Potash or soft soaps, three varieties of ; Transparent soap ; Grained soaps ; Elaidin soft soap ; Silver-soap ; Boiling of soaps . . . 286 Boiling by steam ; Use of direct and indirect steam ; Treatment of the soap-paste obtained by boiling with steam . . . . .288 Boiling with indirect steam ........ 289 XX CONTENTS. PAGE Boiling of resin-grain soaps ; Calculation of the necessary quantities of fat and alkali by the atomic theory . . . . . . .290 Table of the quantities of fat which a soda lye of Baume's or Twaddle's degrees requires for saponification ....... 294 Table of the quantities of fat which a potash lye of Baume's or Twad- dle's degrees requires for saponification . . . . . .295 In every chemical equation, hence in saponification, the product (soap) is equal to the educt— sodium oxide, potassium oxide, water, fat, or oil ; Triglycerides, per cent, of stearin, palmitin, olein, oil, or fat con- tained in the . . . . . . . . . . . 296 Yield from tri-glycerides after saponification with water . . . 297 Modern methods for the manufacture of soap ; Saponification by sul- phuretted alkalies .......... 298 Direct saponification of oil fruits ; Normal soaps . . . .299 CHAPTER XII. HARD SOAPS. I. Curd or Graix-Soaps. Curd or grain-soaps upon sub-lye ; Old German curd-soap ; Conversion of tallow into curd-soap 300 Proper salting out of soap . 302 Tallow (curd) soap 303 Test of the complete saponification of tallow ..... 305 Preparing curd-soap without boiling it clear upon sub-lye; Fabrication of tallow (curd) soap with caustic soda lye ; Marbling or mottling of tallow (curd) soap . . . . . . . .306 Grinding of soap ; Utilization of sub-lye ...... 308 Preparation of " Fulling extract" from sub-lye ..... 309 Recovery of glycerin by osmose, patented by H. Flemming ; Evapo- rating pan for sub-lye illustrated ; Leon Droux's apparatus with re- volving cylinder for evaporating sub-lye, illustrated and described . 310 Use of Glauber's salt in the recovery of glycerin ; Domeyer and Hagemann's patented process for recovering glycerin and other pro- ducts from soap lyes . . . . . . . . .312 Other processes for recovery of glycerin . . . . . .313 Marseilles-soap (olive-oil curd-soap) . . . . . . .314 Soap factories in Marseilles . . . . . . . .315 Division of the operation of making Marseilles-soap . . . .316 Analysis of Marseilles-soap . . . . . . . .319 Marseilles-soap from olive-oil fatty acid ; Palm-oil (curd) soap . . 320 Table of pure palm-oil soaps ; Stettin palm-oil household soap . . 322 Soap from palm-oil and bone-fat ....... 323 Soap from palm-oil and resin or colophony . . . . .324 CONTENTS. XXI PAGE Palmitin-soap . . . . . . . . . . .325 Resin curd-soaps ; Combinations of resin with fats for soap . . 326 Resin curd-soap, 30 pounds resin to 100 pounds fat . . . 327 Resin curd-soap, 40 pounds resin to 100 pounds fat; Resin curd-soap, 50 pounds resin to 100 pounds fat . . . . ." . . 328 Resin curd-soap, 100 pounds resin to 100 pounds fat according to the American method ; Dark resin curd-soap ..... 329 Analyses of resin-soaps . . . . . . . . . 330 Olein-soap ........... 331 Soap from fuller's- fat ......... 332 Wool-fat soap . 334 Curd-soap from fish-tallow ; Yellow curd-soap ..... 335 Apollo-soap . . . . . . ' . . . . . 336 Turpentine soap . . . . . . . . . .337 Russian saddle-soap . . . . . . . . . .338 Sinclair's English cold-water soap ; Augmentation of curd-soaps . 339 Curd-soap upon a precipitate of paste ; Object to be attained in soap boiling ............ 341 Wax-soaps ; Operation of direct boiling ...... 342 Combination of fats which necessitate the process of indirect boiling; Operation by indirect boiling ........ 343 Remarks upon the necessary quantity of lye in saponifying ; Prime white curd-soap (wax-soap) ........ 345 Soap from palm-kernel oil and oleic acid ; Soap from cotton-seed oil and palm-kernel oil ; Lye for boiling smooth white curd-soap by the direct method, preparation of ....... 347 Boiling smooth white curd-soap with the use of direct steam ; Value of animal tallow in household soaps ....... 348 Formulas for beautiful white soaps ; Value of American lard in making white curd-soap . . . . . . . . . 349 Second quality of smooth white curd-soap ; Smooth curd-soaps with resin ............ 351 Formulas for curd-soaps with resin . . . . . . .352 Oranienburg curd-soap ; Formulas for winter and summer manufacture 353 Yellow resin curd-soap, palm-kernel oil soap, or yellow curd-soap . 355 CHAPTER XIII. HARD SOAPS (CONTINUED). II. Paste Soaps. Characteristics of paste soaps ........ 356 Materials used in augmenting paste soaps ; Paste soaps with a yield of 250 to 275 per cent. ; Formulas and processes for best smooth white or colored soaps . . . . . . . . . .357 XX11 CONTENTS. PAGE Formula and process for a yellow soap with a yield of 275 per cent . 359 Tallow-soda soap, formula and process for best qualities . . 3G1 Paste soaps with a yield of 300 to 350 per cent. ; English mottled (Eschweg-soap, III) soap . . . . . . . .363 Talc as a filling material ; Formula for a better quality paste-soap with cocoanut-oil, with palm-kernel oil . . . . . .364 English mottled-soap (Eschweg-soap, III), suitable formula for . . 365 Testing the base-soap for coloring and marbling . . . . .366 Resin-paste soaps, formulas and process of manufacture . . .367 Formulas for finer qualities resin-soap . . . . . .368 Brown resin paste-soaps, formulas for ; Paste soaps with a yield of 500 to 600 per cent., formula and process for . . . . .369 Coloring of resin soaps ; Formula for resin soap with talc filling . 3 70 Formulas for resin soaps with water-glass and talc filling . . .371 Marbling resin soaps by formation of flux . . . . .372 Liverpool-soap; Transparent resin paste-soap . . . . .373 Transparent resin-soap, another method . . . . . .374 CHAPTER XIY. HARD SOAPS (CONTINUED). III. Half-Grain Soap. Three methods of preparing half-grain soaps ; Half-grain soaps by the indirect method . . . . . . . . . .375 Precautions in manufacture of half-grain soap ; Formula for manufac- ture of 376 Remedies for imperfections encountered in the boiling of half-grain soaps ; Half-grain soaps prepared with cocoanut-oil ; Use of car- bonates in summer and in winter . . . . . . .3 78 Manufacture of half-grain soaps with palm-kernel oil alone ; Uncertain boiling of half-grain soaps with a less quantity of palm-kernel oil or cocoanut-oil than one-half the charge of fat . . . . .379 Preventing too strong drying out in soaps filled with water-glass and talc 380 Tests when soaps may be considered finished ; Use of talc as a filling agent . . . . . . . • • • • .381 Mixture of crystallized soda and water-glass as a filling agent ; Use of talc and rice- flour in addition to the soda and water-glass mixture ; Another process for half-grain soap ...... 382 Oldest and simplest method of preparing half-grain soap . . . 383 Tests for sampling soaps during the boiling ; Directions for using water- glass ............ 384 Formula for soap from good fats ....... 385 Use of lyes from lyes of curd-soaps ; Formula for a combining lye in the saponification of palm-kernel oil ..... 386 CONTENTS. XX111 Preparation of grain to be kept on hand ...... Tests for use of shortening agents ; Formation of flux in half-grain soaps Formula for soap with bone-fat, or glue-fat, cotton-seed oil, horse-fat, and cocoanut-oil ......... Formula for half-grain soap from lardaeeous fats, bone-fat, and palm kernel oil ........* Half-grain soaps from bone-fat and palm-kernel oil ; Directions for use of soap scraps containing talc ...... Preparation of a hard soap from a combination in which paste-forming fats have the proportion of 7 to 10 of the others Formula for soap with use of talc for filling .... Formula for soap from bone-fat, cotton-seed oil, horse- fat, and palm kernel oil ......... . Half-grain soap by the direct method ...... Formula for soap by the direct method ..... Formula for the boiling-lye used in the direct method Formula for a soap to be filled with water-glass and cocoanut-oil as a combining fat .......:. Soap from palm-kernel oil and linseed-oil or cotton-seed oil Use of oleic acid in direct boiling ; Half-grain soaps from base- soap Coloring of half-grain soaps ; Boiling of half-grain soaps in general Formula for a good half-grain soap with a yield from 200 to 225 per cent. ........... Formula for a soap yielding 200 per cent. ..... Variety of half-grain soap with use of fuller's and other cheap fats PAGE 387 388 389 390 391 392 393 394 396 397 399 400 401 403 406 407 411 413 CHAPTER XV. MANUFACTURE OF SOAP BY THE COLD PROCESS. Fats for saponification by the cold process . . . . .415 Cocoanut-oil, principal varieties of, and their special characteristics . 416 Process of washing oil with salt-water to remove dirt and mucus mecha- nically fixed in the oil ; Refining or bleaching oil with lye . .417 Only the freshest cocoanut-oil should be used for saponification by the cold process ........... 418 Lyes for the cold process of saponification . . . . . .419 Filling for soaps by the cold process ; Object to be attained by filling 420 Principal agents used in filling ; Potash solution ; AVater-glass . . 421 Solution of soap as filling ; Talc ....... 422 Marbling of soaps prepared by the cold process . . . . .423 XXIV CONTENTS. CHAPTER XVI. SOFT SOAPS. PAGE Characteristics and composition of soft soaps . ' . . . . 424 Smooth transparent soft soap ........ 425 Proportion of soda lye used with potash lye for soft soap ; Experiments of Greve and Gentele ; Formula for calculating the yield of soft soap with the use of potash and soda lye ...... 426 Smooth soft soap from linseed-oil . . . . . . .427 Preparation of the lye for saponification of linseed- oil ; Process of boiling the soap .......... 428 Testing the saponification of the oil ; Storing the soap . . . 429 Particular remarks on the saponifying process ; Tests for the proper proportion of lime . . . . . . . . .430 Precautions to be observed in boiling ; Fitting the soap . . .431 Influence of soda upon the durability of the soap; When resin is added to the soap ; The process for the manufacture of all soft soaps ; Glycerin soft soap . . . . . . . .432 Working of oil bleached with lye; To increase the yield and the lathering property of the soap ; Preparation of the lye ; Prepara- tion of the soap .......... 433 Yield of soap ; Method of utilizing the dark precipitate resulting from bleaching linseed-oil with potash lye . . . . . .434 Soft soap from train-oil, from hempseed-oil ; Natural grain soft soap (fig-soap) ........... 435 W T orking with unpurified old tallow ; Materials used, and preparation of the lyes 436 Formula for pale-yellow soap with rice-like grain ; Dark-yellow soap with rice-like grain ; Pale soap with small rye-like grain ; Dark soap with small rye-like grain ; Soap with a beautiful medium grain, summer and winter formulas . . . . . . .437 Soaps for fulling purposes, summer and winter formulas; Conditions to be observed in order to obtain good natural grain-soap . . 438 To carry on the boiling process with ease and rapidity ; Calculation for the average lye ; Phenomena connected with the boiling . . 439 Testing the soap for flower ; Coloring the soap ; Perfuming and storing the soap . . . . . . . . . .441 Natural grain-soap with stearin ; Artificial grain-soap . . . 442 Yellow artificial grain-soap ........ 443 Green artificial grain-soap ......... 444 Brown artificial grain-soap; Soft soap with a mother-of-pearl lustre . 445 Formula for white elaidin soap, for yellow soap, for good fulling soap in summer and in winter ; Explanation of the term horse-fat . . 446 Smooth elaidin soap . . . . . . . . . .447 CONTENTS. XXV PAGE Tests for a correct fit ......... 448 White soft soap or bleaching soap ; German so-called tallow soft soap ; Filling of soft soaps . . . . . . . . . 44 9 Components and use of sapolite ; Receipts for preparing the filling lye 450 Potash water-glass, potassium-filling, and potato-starch for filling soaps 451 CHAPTER XVII. SOAPS FOR THE TEXTILE INDUSTRIES. Bar-soaps and barrel-soaps — varieties of soaps used in these industries . 452 Bar-soaps ; Ordinary fulling soaps ....... 453 Guide for testing samples of soaps ; Formulas for imitating soaps . 454 Process of boiling .......... 455 Neutral curd-soaps ; Formula for a neutral tallow- or palm-oil soap ; Lyes ............ 456 Formulas for neutral palm-oil or tallow-oil soaps . . . .457 Olein-soaps, formulas for; Remarks on the various brands of olive-oil 458 Soaps from green sulphur olive-oil . . . . . . .459 White olive-oil soap .......... 460 Grain-soaps upon a precipitate of paste, formulas for . . . .461 Barrel or soft soaps ; Natural grain-soaps, formulas for, and methods of boiling ........... 463 Olein soaps, formulas for, and methods of treatment .... 466 Smooth oil-soap, formulas for . . . . . . . .467 CHAPTER XVIII. MANUFACTURE OF TOILET SOAPS, SHAVING CREAMS, MEDICATED SOAPS, ETC. V Four distinct processes for the manufacture of these soaps ; Toilet soaps by the warm process ; Cocoanut-oil soap with a yield of 300 to 320 per cent, by the warm process . . . . . . .4 69 Transparent soaps . . . . . . . . .470 White alabaster-soap ; Eau de cologne transparent glycerin-soap ; Transparent glycerin-soap . . . . . . . .472 Toilet soaps by the cold process ; Bitter-almond soap ; Filled bitter- almond soap ; Honey-soap ; Honey-soap (filled) ; Bergamot-soap ; Alpine-flower soap . . . . . . . . .473 Bismarck-soap ; Brown-eagle soap ; Pumice-soap ; Bouquet-soap ; Chi- nese-soap ; Marshmallow (althea) soap . . . . . .474 Glycerin cold-cream soap ; Milletfeurs-soap ; Musk-soap ; Omnibus- soap ; Rose-soap; Vanilla-soap . . . . . . .475 Vanilla-soap, superfine ; Violet-soap ; Violet-soap (English) ; Wind- sor-soap (brown) . . . . . . . . . .476 XXVI CONTENTS. PAGE White windsor-soap ; Toilet-soaps by remelting ; Tallow-soap ; Oil- soap ; Castile-soap ; Palm-soap ... . . . . .477 Yellow-soap; Marine-soap; White fig-soap ; Naples soft-soap ; Dopp & Son's improved kettle for remelting soap, illustrated and described 478 Dopp & Son's remelting crutcher, with and without engine attached, illustrated and described . . . . . . . .479 Economic process of making fine grade toilet-soap by use of Dopp's remelter and crutcher . . . . . . . . .482 Cheap process of making a toilet-soap equal to milled-soap . . . 484 Steam-jacket remelter, illustrated and described .... 485 Whitaker's remelter, illustrated and described . . . . .486 Formulas for almond-soap, camphor-soap, honey-soap, pumice-soap, sand-soap, and old brown windsor-soap . . . . . .488 For brown and white windsor-soap ; French system of making toilet- soaps or milled-soaps . . . . . . . . . 489 Soap-stripper or clipper, illustrated and described .... 490 Power soap-clipper (Alfred Houchin's), illustrated and described . 491 Rutschman's automatic soap-clipper, illustrated and described . .492 Soap-mill for blending the shavings into a thick homogeneous paste, illustrated and described . . . . . . . .493 Soap-mill with four rollers, illustrated and described; Rutschman's soap-mill, illustrated and described ...... 494 Soap-plodder, illustrated and described . . . . . .496 Hydraulic plodder, illustrated and described . . . . .498 Boudineuse plodder, illustrated and described ..... 499 Compound helix continuous plodder, illustrated and described . . 500 Cutting machine, illustrated and described ... ... 501 Soap-presses; Hand-press, illustrated; Rutschman's foot-power press, illustrated and described ; Houchin's soap-stamping press with box and dies, illustrated and described ....... 502 Dopp & Son's improved foot-level soap-press, illustrated and described 503 Dopp & Son's steam soap-press, illustrated and described . . . 505 Finishing and polishing the soap-cakes . . . . . .507 Coloring toilet-soaps ; Stock soaps for milled toilet-soaps . . . 508 Palm-soap as stock-soap for toilet-soap ; Cocoanut-oil soap for toilet purposes ; White-soap from cocoanut-oil ..... 509 Formulas for half-palm soap . . . . . ". . .510 Process of preparing half-palm soap . . . . . . .511 Operation to completely refine the soap . . . . . .512 Results obtained from fatty matters by the foregoing process . . 513 Formulas for milled soaps — Savon de Guimauve (Marshmallow-soap), Savon a. la Rose, Savon aux Fleurs d' Italie, Savon de Crimee, Savon de palme, Savon a. la violette . . . . . .514 CONTENTS. XXVI 1 PAGE Elder-flower soap ; Lemon-soap ; Orange-soap ; Patchouli-soap ; Helio- trope-soap ; Frarigipanni-soap ; Cold-cream soap .... 515 Savon de riz ; Savon au bouquet; Herb-soap (Dr. Borchardt's) ; Lily- soap; Superfine toilet-soaps ; Ambergris-soap; Benzoin-soap . 516 Jonquille-soap (superfine) ; Millefleurs-soap ; Savon &, la Marechale (surfin) ; Savon hygienique (extra fine) ; Savon a la violette de Parme . . . . . . . . . . 517 Lettuce-soap ; Cucumber-soap ; Rose-leaf soap (extra fine) ; Shaving soap; Shaving soap by the cold process ...... 518 Paris transparent shaving soap ; Shaving soap by the warm method ; English shaving soap . . . . . . . . .519 Windsor-soap for shaving ; Soft toilet-soaps ..... 520 Soap kettle with double bottom heated by steam, illustrated and de- scribed . ... .'*"' ...... 521 Formulas for various soft toilet-soaps ; Almond shaving cream, rose shaving cream, ambrosial shaving cream, Naples shaving cream, shaving cream ; Rypophagon-soap ; Creme d'ambrosie ; Liquid gly- cerin-soap ........... 522 Amandine ; Olivine ; Glycerin jelly ; Soap balls or savonettes ; Medi- cated soaps ............ 523 Formulas for medicated soaps prepared by Dr. P. G. Unna ; Super -fat salicylic soap ; Super-fat zinc salicylic-soap ; Super- fat tar-soap . 524 Super-fat sulphur-soap; Super-fat tar sulphur-soap; Super-fat cam- phor sulphur-soap ; Super-fat camphor-soap ; Super-fat borax-soap ; Super-fat iodine-soap ; Super-fat naphthol-soap ; Super-fat naphthol sulphur-soap ; Other formulas for medicated soaps ; Benzoin-soap, camphor-soap in the cold way, carbolic-soap, carbol-glycerin soap . 525 Iodine-soap for skin eruptions ; Sulphur-soap ; Tar-soaps ; Tannin- soap ; Vaseline tar-soap ; Thymol-soap ; Croton-oil soap ; Castor-oil soap ............ 526 Petroleum-soap ; Paraffin-soap ; Creasote-soap ; Turpentine-soap ; Alum-soap ; Mercurial-soap; Irish-moss soap; Bran-soap; Corn- meal-soap; Oat-meal soap ; Gall and scouring soaps, formulas for . 527 Breslau scouring soap ; Floating soap ...... 528 CHAPTER XIX. VOLATILE OILS AND OTHER MATERIALS USED FOR THE PERFUMING OF SOAPS. Volatile oils as found in commerce ; Oil of bitter almonds ; Adultera- tions and tests for .......... 530 Oil of bitter almonds (factitious), nitrobenzole, oil of mirbane, essence of mirbane, etc.; Bergamot-oil ; Caraway-oil; Cassia-oil . . 531 Cinnamon-oil (genuine) ; Citron-oil; Citronella-oil ; Oil of cloves . 532 XXV111 CONTENTS. PAGE Cumin-oil; Fennel-oil; Geranium-oil or ginger-grass oil; Oil of jas- min ; Lavender-oil ......... 533 Oil of lemons ; Oil of limes or limette-oil ...... 534 Marjoram-oil ; Neroli or orange-flower oil ; Nutmeg-oil (volatile) ; Orange-peel oil or Portugal-oil ; Pachouli-oil ..... 535 Pimento-oil or oil of allspice; Rose-oil or attar of roses . . . 536 Rosemary- oil ; Sassafras-oil . . . . . . . .537 Thyme-oil; Vitivert or vetiver-oil ; Wintergreen-oil ; Peruvian balsam 538 Ambergris ; Civet ; Musk . . . . . . . . .539 Tincture of ambergris ; Tincture of civet ; Tincture of musk . . 540 CHAPTER XX. SOAP ANALYSIS. Determination of the content of water . . . . . .541 Determination of the content of fatty acid . . . . . .542 Determination of non-saponified fat ; Determination of the kinds of fats used in the preparation of soap ; Determination of resin . . 543 Determination of alkalies ......... 544 Whether a soap contains free alkali, i. e., caustic alkali or carbonate; Determination of glycerin ........ 545 Determination of alcohol, of volatile oils, and of filling agents . . 546 Determining the portion of the residue soluble in water ; To test for glue ; Determining mineral oils and mineral fats, talc, he.avy spar, infusorial earth, etc.; Prof. Albert R. Leeds's scheme for analysis of soap . . . . . . . . . . . .54 7 PART II. THE MANUFACTURE OF CANDLES. CHAPTER I. INTRODUCTION. Historical notice . . . . . . . . . .551 Evolution of light by the candle; Frederick Knapp on the functions of the candle ........... 553 Candle-wicks ; Physical and chemical processes in a burning candle . 554 Principal conditions for the regular process of illumination . . . 555 Principal task of the illuminating material ...... 556 Evolution of the burning gases, their combustion and the shape of the flame illustrated and described . . . . . . .557 CONTENTS. XXIX PAGE Consumption of oxygen caused by illuminating materials; Carbonic acid generated ; Development of acrolein ; Test of the value of an illuminating agent .......... 558 The physical law upon which photometery is based .... 559 Relative quantities of illuminating materials to give the same amount of light 560 CHAPTER II. MATERIALS FOR CANDLES. Paraffin, its discovery and development; Selique's discoveries in con- nection with the paraffin industry ....... 561 Paraffin industry in Scotland ; Distillation and purification of the crude oil 563 Paraffin in the United States ........ 564 Chemical characteristics of paraffin ; Ozokerite or mineral wax . . 566 Melting point of paraffin obtained by distillation; Reichenbach's pro- cess of purifying the crude paraffin; Ceresin, extraction of, specific gravity, melting point, and congealing point . . . . .567 Ozokerite paraffin for the manufacture of candles . . . . 568 Waxes 568 Waxes of animal origin ; Beeswax; Purification of crude wax . . 568 Bleaching the yellow wax ; White wax, characteristics of, melting point, and specific gravity . . . . . . . .569 Wax, adulterations of and tests for . . . . . . .570 Chinese-wax; specific gravity and melting point .... 571 Spermaceti ; Source of, specific gravity, and melting point . . 572 Waxes of vegetable origin ; Japan- wax, melting and congealing points 573 Fig-wax or Getah-wax ; Cowtree-wax ; Myrica-wax or myrtle tallow 574 Carnauba-wax, specific gravity and characteristics of; Mixtures with stearic acid, with ceresin, and with paraffin ; Table of Valenta's de- termination of the melting point of these mixtures . . . .575 Palm-wax ; Ocuba wax ; Balanphore-wax ; Andaquies-wax ; Cuba- wax ; Sebacylic acid . . . . . . . . . 576 CHAPTER III. MANUFACTURE OF CANDLES. Wicks and their preparation ; Twisted wicks for tallow-candles . .577 Plaited wicks for stearin, paraffin, spermaceti, and many composite candles ; Wick mordants, compounds for ..... 578 Twisting of the wicks, apparatus for, illustrated and described . . 579 Wick-cutting apparatus, illustrated and described .... 580 Dipped candles ; Hardening the tallow ...... 582 XXX CONTENTS. PAGE Equalizing dipped candles, apparatus for, illustrated and described . 583 Dipping candles on a large scale, apparatus for, illustrated and described 584 Moulded candles ; Apparatus for moulding, illustrated and described . 587 Moulding candles by hand, apparatus for, illustrated and described . 588 Moulds without head-pieces, illustrated and described; Moulding ma- chine for tallow-candles, illustrated and described . . . . 589 Morgan's moulding machine for tallow-candles, illustrated and de- scribed . . . . . . . . . . . .591 Plated candles ; two methods of making ; Improving the whiteness of tallow- candles .......... 595 Stearin candles; Myristic and lauric acids, table of; Melting and con- gealing points, mixtures of, and manner of congealing . . . 596 Palmitic and myristic acids ; Stearic and palmitic acids, tables of melting and congealing points, and manner of congealing of, mix- tures of . . . . . . . . . . . .597 Stearic and myristic acids ; Palmitic and lauric acids ; Stearic and lauric acids ; Tables of their melting point, and manner of con- gealing of, mixtures of . . . . . . . . .598 Margaric acid and myristic acid; Margaric acid and palmitic acid; Tables of the melting point and manner of congealing of, mix- tures of ... . ........ 599 Stearic and margaric acids; Palmitic, myristic, and stearic acids; Tables of the melting point and manner of congealing of, mix- tures of 600 Myristic, lauric, and palmitic acids ; Table of melting points and manner of congealing of mixtures of; Phenomena in mixing fatty acids, like those of metals, as affecting their melting point . . 601 Wicks for stearin candles; Melting purified stearic acid; Melting- kettle, illustrated and described ....... G02 Moulding apparatus for candles, illustrated and described . . . 603 Continuous wick-machine for candle- moulding, illustrated and de- scribed ............ 604 Accurate centering of the wicks in moulding machines, Grotowski's apparatus for, illustrated and described ...... 606 Easy removal of the candles from the moulds, A. Royan's apparatus for, illustrated and described ........ 609 Motard's combined moulding and cutting apparatus, illustrated and described . .. . . . . • . . .611 Moulds for candles to prevent their dripping, illustrated and described ; Moulds for candles in two parts to avoid wasted ends, illustrated and described . . . . . . . . . . .615 Spermaceti candles, and paraffin candles . . . . • .616 Melting points of paraffin derived from various sources ; Black paraffin- candles . . . . . . . . . . . .617 CONTENTS. XXXI PAGE Manufacture of wax-candles and wax-tapers, apparatus illustrated and described ........... 618 Roller for finishing and polishing candles, illustrated and described ; Wax-tapers ; Apparatus for making, illustrated and described . 620 A good composition for wax-tapers : Polishing of candles ; Candle- polishing machines, illustrated and described ..... 622 Bleaching of candles ; Composite-candles; Adamantine-candles; Cero- phane-candles ; Diaphane-candles ; Melanyl-candles . . . 625 Parlor bougies ; Transparent bougies ; Composition-candles ; Deco- rated-candles . . . . . . . . . .626 Varnish as a ground for decoration of candles ; Decorated-candles, illustrated 627 Coloring of candles ; Receipts for blue, green, red, yellow, purple, or violet colors ........... 628 APPENDIX. List of patents relating to soap and candles, issued by the Government of the United States of America, from 1790 to 1888, inclusive: — Rendering of fats Decomposition of fats Bleaching of fats and oils Soap manufacture Soap cutting Soap Detergents Candles and apparatus 629 632 633 633 635 636 643 644 Index , . 647 PRACTICAL TREATISE ON THE MANUFACTURE OF SOAP AND CANDLES. PART I. MANUFACTURE OF SOAP. CHAPTER I. HISTORY OF THE MANUFACTURE OF SOAP. If we inquire into the origin of the manufacture of soap, we find that a detergent corresponding to our soap is not mentioned by any writer before the Christian era. It is frequently asserted that soap was known to the authors of the Old Testament ; but the Hebrew words used in the passages* are stated by authori- ties to refer to vegetable and mineral lyes, i. e., potash and soda in some form. In Homer's time the cleansing of clothes seems to have been eifected by simply rubbing or pounding in water without any addition, for he tells how Nausicaa and her attendants washed clothes by stamping them with their feet in pits filled with water. Later on the juices of certain plants were employed as deter- gents and also natural soda and wood ashes, and the fact that the strength of alkalies can be increased by lime was already known to Paulus ,ZEgina. Fuller's earth was, however, the principal agent used for washing in ancient times, the fuller's art being due, it appears, to one Nicias, the son of Hermais. The Roman * Jeremiah ii. 22, and Malachi iii. 2. 18 MANUFACTURE OF SOAP AND CANDLES. fullers (fullones), who washed dirty garments, were persons of no little importance. Their trade and the manner of carrying it on were regulated by laws. At one time, fuller's earth, found of a superior quality in Staffordshire, Bedfordshire, and other counties of England, was considered so indispensable for the dressing of cloth that, to prevent foreigners from rivalling English fabrics, it was made a contraband commodity, and its exportation made equally criminal with the heinous and wicked export of wool. The elder Pliny gives us the earliest account of soap as having been first manufactured by the Gauls, and used by them as a cos- metic, and for dyeing the hair red. He also states that it was made from tallow and ashes, the best being prepared from goat's suet and beechwood ashes, and that the Gauls employed it both in a solid and liquid form. Erom this statement by Pliny it has been generally concluded that the invention of soap was due either to the Gauls or the Germans. E. Moride,* however, contests the correctness of this conclusion. He is of the opinion that Pliny's statement simply refers to the application of soap as a cosmetic and hair-dye, and believes the Phoenicians, who settled in Gaul 600 B. C., to have been the actual inventors of soap. It cannot, however, be supposed that the first soap was an artificial product like that of the present day. It was very likely a mixture of oil and wood ash, which was used as a salve in eruptions of the skin and similar diseases. Later on it may have been accidentally discovered that a more effective salve was obtained by mixing the ash with water and burnt lime before com- bining it with the oil. Thus, no doubt, products were gradually obtained which resembled the present soaps of Algiers, of which Leon Droux writes :f " In the interior of Algiers the Cabyles bring to market a mass which serves the double purpose of a remedy and for household use. It is a soap prepared almost in the cold way, of a slightly yellowish color, somewhat transparent, and of a jelly-like consistency, but with a very small content of water. It is made from olive-oil and lye, the latter being prepared by * Les Corps gras industrielles. f Les Produits Chimiques, Paris, 1878, p. 186. HISTORY OF THE MANUFACTURE OF SOAP. 19 allowing water to percolate through a mixture of wood ashes and burnt lime. The Arabs use the salve-like product thus obtained for affections of the skin, as well as for household purposes, and washing wool to be worked into tissues." As a detergent, soap is first mentioned by the authors of the second century after Christ. The celebrated physician, Galenus, speaks of it as a detergent, as well as a medicament, and considers the German soap as the best, and the Gallic as the next best. But little is known of the further gradual development of the soap industry. Marseilles, it is said, carried on a considerable trade in soap as far back as the ninth century. In the fifteenth century Venice was the principal market, but was outstripped, in the seventeenth century, by Savona,* Genoa, and Marseilles. At the same time the manufacture of soap seems to have been carried on to a considerable extent in England, where, in 1622, a com- pany obtained a monopoly for the manufacture of soap, paying annually a tax of £20,000 for 3000 tons of soap. As some of the soap-boilers did not join the company, many disputes arose in consequence of this grant, until the king issued an order that no soap should be sold except it was examined by the company. In 1633 sixteen soap-boilers were summoned before the Star- Chamber for disobedience of this order and infringement of the grant. The accused were condemned to pay a fine varying from £500 to £1500, and to be imprisoned at the king's pleasure. This judgment was executed, two of the soap-boilers dying in prison while the others were liberated after forty weeks. In 1635 the holders of the monopoly offering to pay £2 more tax per ton, their privileges were increased, and a few more soap- boilers, disobeying the mandate, imprisoned. In 1637 the patent was finally bought from the patentees for £40,000, and the factory buildings for £3000. The materials the London soap- boilers had to purchase for £20,000 before they were allowed to carry on their trade. In France the monopoly system was also in force in the seven- teenth century. In 1666 Pierre Bigat, a merchant of Lyons, made a proposition to the king to manufacture, by special methods, * Whence the French name of soap (savon). 20 MANUFACTURE OF SOAP AND CANDLES. sufficient soap for the consumption of France without importing any of the materials required in the manufacture. Louis XIV. accepted the proposition and gave him the sole privilege for 20 years of erecting factories for the manufacture of white, marbled, and all other kinds of soap, in any place it suited him. The six or seven factories then in existence were allowed to remain, but under the condition that they should not increase their capacity, and would sell their products to Rigat at a fixed price. This patent, being the cause of many disputes, was revoked in 1669. Many complaints about the adulteration of soap caused the French government, in 1688, to issue special directions for the manufacture. It was decreed (1) that all soap-makers, no matter what kind of soap they produced, must stop the manufacture during the months of June, July, and August of every year ; (2) that new oils should not be used in the manufacture of soap before the 1st of May of every year ; and (3) that besides barilla, soda, ash, and olive-oil, no other fats or materials should be em- ployed. This decree was partially revoked in 1754, and the manufacturers were allowed to work during the entire summer. Six years later the factories were again ordered to close during the summer, though this time the decree was issued on the recom- mendation of the soap-boilers themselves. The Revolution of 1789 did away with all these useless restrictions. But little is known about the soap industry in Germany during the early centuries. The business was carried on on a small scale, and this could not well be otherwise, since, with the impure raw materials, principally crude tallow and wood ashes, one boil- ing frequently required as many days as hours at present. The industry was further hindered by the general practice of every household preparing its own soap, which continued up to the in- troduction of artificial soda and tropical vegetable fats. But since then many large factories have been established, and, as the German soap-boilers applied to the trade its true chemical character, they produced superior goods. The soft soap of Ger- many is still much used for household purposes as well as for manufacturing, and it has acquired a reputation for excelling in quality that of other countries. In this country there has been a steady progress in the im- HISTORY OF THE MANUFACTURE OF SOAP. 21 provements constantly making in this important branch of in- dustry, until now we are producing goods which for quality compare favorably with any made elsewhere ; moreover, we have invented much new and improved machinery and apparatus that greatly facilitate the processes, saving labor and time and im- proving the quality. Thus the United States is at this time but little behind any other country, either in the amount made or in the quality of the article ; while in the economy and facility of their manufacture this industry is fully abreast, if not in advance, of that of nearly all other countries, and is steadily progressing, so that it cannot be long before Ave shall equal in quality and excel in quantity. Not much advance was made in the manufacture of soap until at the beginning of the present century it commenced to attract the attention of scientific men, and Leblanc gave to the world his splendid process for the production of soda from common salt. But, like many other benefactors of the human race, Leblanc did not reap the reward for his invention. In 1791 a patent for fifteen years was granted to him in France, which was, however, shortly after revoked. The manufactory, which Leblanc had established by the aid of the Duke of Orleans, was just beginning to work when the Revolution put an end to all business ; the property of the Duke of Orleans was seized, and the factory being included, the fabrication was stopped. Soon, the Continental war preventing the importation of Spanish sodas, the French in- dustry felt the loss of this important element so essential to its work. Then, on the proposition of Carnot, the Committee of Public Safety obliged Leblanc to sacrifice to the country the fruit of his discovery by making it public. Leblanc was ruined, and after many struggles for redress fell a victim to melancholy, and died, in 1806, by his own hand and in abject poverty. The next great discovery, and not second in importance, was due to Chevreul, who, by describing the exact constituents of the fatty bodies and making known the processes for their separa- tion, raised soap-making from empiricism and guess-work to its present position as a truly scientific art. By establishing the practical and scientific basis upon which the soap industry is now 22 MANUFACTURE OF SOAP AND CANDLES. carried on, Leblanc and Chevreul may be considered as its founders. The introduction of new fats and oils, especially of palm-oil, palm-kernel oil, and cocoanut-oil, added an important variety to the lists of soaps, particularly of toilet-soaps. Of great import- ance, also, was the introduction of caustic soda, which enabled the soap-boiler to prepare with great ease caustic lyes of a high degree. Soap is one of those products whose capital value, disappearing constantly from circulation, has to be renewed ; it is one of the most important products which, after use, are absolutely of no value. With old pieces of glass, window-panes can be pur- chased, and with rags, clothing ; but with soap-water nothing can be done in our households. To be sure, in modern times many attempts have been made to collect the soap-waters from large wash-houses and to separate the fatty acids by sulphuric acid, but this represents but a very small quantity of the fat lost in this way. RAW MATERIALS USED IN MANUFACTURE OF SOAP. 23 CHAPTER II. RAW MATERIALS USED IN THE MANUFACTURE OF SOAP. The ordinary soaps of commerce consist of the more or less pure sodium or potassium salts of fatty acids. They are pre- pared by subjecting fats and fat oils, and also fatty acids, to the action of lyes. The latter are prepared by treating aqueous solu- tions of alkaline carbonates (soda or potash) with caustic lime, or by simply dissolving the caustic alkalies in water. For some soaps an addition of rosin is also used. The raw materials used in the manufacture of soap consist, therefore, on the one hand, of fats, fat oils, fatty acids, and rosin, and, on the other, of alkalies. To these must be added, as auxil- iary raw materials, water, lime, and common salt. With these few preliminary remarks we shall proceed to the description of the raw materials, their properties as far as of in- terest to the soap -manufacturer, and the methods of examining them. Fats. Constitution of fats. — To understand the chemical process which takes place during saponification it will be necessary to consider the physical and chemical properties of fats. The term "fats" is applied to certain products of the animal and vegetable kingdoms with the following common properties : they feel unctuous to the touch and form oleaginous fluids, either at an ordinary temperature or when heated. Dropped upon paper they cause transparent stains which do not disappear in time nor by the application of heat. In an absolutely pure con- dition they are all colorless, inodorous, and tasteless, but, in con- sequence of the presence of foreign substances, the commercial products are generally more or less colored ; the solid fats being yellowish, the oils yellow or yellow-green, and the train-oils red 24 MANUFACTURE OF SOAP AND CANDLES. or red-brown. They are lighter than water and insoluble in it, and but slightly soluble in alcohol, but freely in ether, carbon bisulphide, and volatile oils. They commence to boil at from 572° to 600° F., whereby they are decomposed, forming volatile acids of a disagreeable and irritating odor. At a still greater heat they form a combustible gas which has three times the illuminat- ing power of coal-gas and is of much greater purity. According to their consistency, the fats are divided into solid fats or tallows, semi-solid fats or butters aud lards, fluid fats or oils, and train-oils, the latter term being applied to the fluid fats de- rived from various marine animals. The solid fats melt readily, most of them becoming fluid below 212° F., while the liquid fats, i. e., oils, assume a firm consistency at a low temperature. The oils, of all fluids, expand the most by heat, and, indeed, in some cases to such a degree as to render it necessary, for the purposes of commerce, to know exactly the extent of the expan- sion. For every degree of Celsius the volume of olive-oil in- creases, according to Preisser, 0.83, of rape-oil 0.89, and of train- oil 1.10 ; so that 1000 measures of olive-oil, at 32° F., will be- come, in summer, at 68° F., 1016.6 measures, 1000 of rape-oil 1017.8, and 1000 of train-oil 1020. By exposure to the air most fats undergo a gradual change. By the absorption of oxygen several of the liquid fats dry up and are converted into a solid transparent substance. Such oils are called " drying oils." Others, called " non-drying oils" never dry up entirely, but only acquire a greater degree of consistency and turn rancid, the latter being due to the formation of an acid. Many solid fats also become rancid ; palm-oil and cocoanut-oil, as found in commerce, being, for instance, frequently in that state of decomposition, though they do not show a bad odor. While pure, unaltered fats, with the exception of castor-oil, are almost insoluble in cold alcohol, they dissolve readily in it when rancid and show an acid reaction; the latter, when not due to ad- mixed foreign substances, always indicates commencement of rancidity, as in a pure, unaltered state the fats are entirely neutral. Chemical constitution. — According to their elementary compo- sition, the fats consist of carbon, hydrogen, and oxygen as distin- guished from the so-called mineral fats and oils, which consist RAW MATERIALS USED IN MANUFACTURE OF SOAP. 25 only of carbon and hydrogen. The following table shows the elementary composition of some of the fats : — Carbon, per cent. Hydrogen, per cent. Oxygen, per cent. 75.20 76.80 76.54 78.00 78.10 77.21 76.50 76.63 77.21 11.90 11.50 11.94 11.00 11.70 13.36 11.91 11.63 13.36 12.90 11.70 11.26 11.00 9.30 9.43 11.59 11.74 9.43 As will be seen from the above table there is a considerable variation in the elementary composition of the fats, and moreover there can scarcely be any doubt that the fat from the same animal is not always alike in composition. The fats, which occur in na- ture, are not simply chemical combinations, but mixtures of such. An important step towards the investigation of the nature of fats was made by Scheele, in 1779, by the discovery, whilst engaged in the preparation of lead plaster, of a sweet body solu- ble in water. He called it " principium clulce oleorum" and it is now generally known as glycerin. But the principal elucidation of the nature of fats we owe to the labors of Chevreul, which commenced in 1812, and culminated in 1823 in the publication of his celebrated work : " Recherches sur les Corps gr as d'origine animate." As a basis for his researches he used a soap from lard and potash, and established the fact that the oxygen of the air had no part in the saponification, as was formerly supposed by many chemists ; that fat once saponified is not altered by repeated combination with potash ; that generally the fats are mixtures and by decomposition with sulphuric acid form acids in the same manner as by decomposition with alkalies ; that the fatty acids obtained by saponification and the glycerin amount to from 4 J to 5 J per cent, more than the weight of the fat used ; that by the combination of fatty acids with lead oxide water is expelled. From the last observations Chevreul concluded that the fatty acids as well as the glycerin contain water chemi- 26 MANUFACTURE OF SOAP AND CANDLES. cally fixed ; he compares the fats with the compound ethers which are decomposed in a similar manner into salt and alcohol with the absorption of water. Chevreul's researches served as a basis for all further studies of the chemical behavior of the fats. The correctness of his obser- vations was in the main confirmed, and his researches extended by others, especially by Berthelot, who enriched our knowledge by the synthesis of the fats from fatty acids and glycerin, and by Heintz, who improved the methods for the examination of fats. Nearly all the fats occurring in nature are peculiar combinations of glycerin, a body composed of 3 equivalents of carbon, 8 of hydrogen, and 3 of oxygen, and are, therefore, termed glycerides. According to the older chemical view, the fats contained a body called glyceryl-oxide or lipyloxide, combined with 3 equivalents of fatty acids, and glycerin was designated as glyceryl-oxide, or as glyceryl-oxyhydrate. But, according to modern chemistry, glycerin is a so-called triatomic alcohol. If, as stated above, glycerin contains 8 equivalents of hydrogen, 3 of them can be represented by acids. If we designate carbon C, hydrogen H, and oxygen O, glycerin has the formula : C 3 H S 3 , which can TT also be written : C 3 H 5 H 3 03, or C 3 tt 5 3 . The 3 equivalents of hydrogen, written separately in the last two formulas, can be rep- resented by acids. Now if 1 equivalent of hydrogen is replaced by an acid, a so-called monoglvceride is obtained ; if 2 equiva- lents are replaced, a diglyceride ; and if all 3 equivalents are re- placed, a triglyceride. By designating an acid R, IT the monoglyceride has the formula C 3 tt f>O a , " diglyceride « « C^ 3 , " triglyceride " " C 3 ^ 5 3 . All glycerides occurring in nature, and others thus far examined, are triglycerides, i. e., glycerin in which 3 equivalents of hydrogen are replaced by acids. The acids contained in fats are generally termed fatty acids, the most important being stearic, palmitic, and oleic acids. Artificially the glycerides can be prepared by heating RAW MATERIALS USED IN MANUFACTURE OF SOAP. 27 glycerin and fatty acids together in closed glass tubes. By heat- ing, for instance, equal parts of glycerin and stearic acid in a closed tube to 392° F. for thirty-six hours, the monoglyceride, i. e., monostearin, is formed. By heating the monostearin with 3 parts of stearic acid to 500° F. for three hours, the diglyceride, i. e., distearin, is obtained, and the triglyceride, i. e., tristearin, by heating monostearin with 15 to 20 times its weight of stearic acid to 518° F. The process may be represented by the follow- ing equations : — Csh 5 °3 + C 18 H °0 = (C 18 H, 5 0)0 3 + H 2 0. ^3 X1 XT Glycerin. Stearic acid. Mouostearin. Water. (C 18 H 3S d)0 3 + c„h °o = (C 18 H 3 ,d)A + h 2 o. H 2 H H Monostearin. Stearic acid. Distearin. Water. (C 18 H, 5 d) 2 3 •+ C 18 H 3j go - (Cjj*p)?* + H * a Distearin. Stearic acid. Tristearin. Water. Many train-oils contain ether-like combinations of another alco- hol, cetyl alcohol (C 16 H 34 0), and wool fat, ether of cholesterin (C 2fi H 44 0), as well as that alcohol itself. Fatty acids. — The fatty acids, which can be separated from the fats, may, according to their composition, be divided into four groups : into acids, 1, of the composition C n II 211 2 (usually called acetic series of acids) ; 2, of the composition C n H 2n _ 2 2 (oleic acid series) ; 3, of the composition C n H 2 „._ 4 2 ; and 4, of the composition C n H 211 _ 2 3 . Of the acetic series of acids the following occur in the fats : butyric acid (C 4 H 8 2 ), caproic acid (C rt H i2 O a ), caprylic acid (C 8 H 16 O a ), capric acid (C l0 H 20 O 2 ), lauric acid (C l2 H 24 2 ), myristic acid (C, 4 H 23 2 ), palmitic acid (C lfi H 32 2 ), stearic acid (C 18 H 36 2 ), arachi- dic acid (C 20 H 40 O 2 ), behenic acid (C 22 H 44 2 ), cerotic acid (C 27 H S4 2 ), theobromic acid (C 84 H 128 2 ). The first four-named acids are known as " volatile fatty acids. 7 ' They are liquid at an ordinary tem- perature, generally oily, and leave grease-stains upon paper which 28 MANUFACTURE OF SOAP AND CANDLES. partially disappear. They are volatile, i. e. y they can be distilled without decomposition, and on boiling with water pass over with the aqueous vapor, though their boiling-point is higher than that of water. They are of little importance as regards the technology of fats, as they occur in them in very minute quantities. The other acids, mentioned above, are the actual fatty acids. At an ordinary temperature they are solid, tasteless, and inodorous, cause permanent grease-stains upon paper, and, with the exception of lauric acid, which passes over with ordinary aqueous vapors, can only be volatilized, without suffering decomposition, in a vacuum, or Avith superheated steam. They are insoluble in water, soluble in burning alcohol, from which, however, after cooling, they re-separate in crystals, bat freely soluble in ether. Their solutions redden litmus only slightly. When heated they ignite and burn with a bright sooting name. They are easily melted. The most important of these fatty acids are lauric, palmitic, and stearic acids, and a knowledge of their properties is required for the examination of the fats. Laurie acid is solid, and when crystallized from dilute alcohol * forms tufts of white, silky needles. Its specific gravity is 0.883 at 60° F. It melts at 109.5° F. The laurates of the alkali metals are amorphous and soluble in water ; the other salts are partially crystallizable, insoluble, or sparingly soluble. Palmitic acid consists of tufts of slender needles. It melts at 143.5° F., and in a fluid state at this temperature has a specific gravity of 0.8527. It solidifies on cooling in a mass of nacreous laminae. The largest portion of it can be distilled without de- composition at about 662° F. It is sparingly soluble in cold alcohol, 100 parts of absolute alcohol dissolving only 9.32 parts. It dissolves abundantly in hot alcohol, so that it can be re-crystal- lized from the solvent. The alcoholic solution shows an acid reaction. Dilute acids have no effect upon palmitic acid ; it dis- solves, however, in concentrated sulphuric acid, but on diluting the solution is re-separated without alteration. Boiling concen- trated nitric acid attacks it very slowly. The salts of palmitic acid resemble very much those of stearic acid (see below), they being only more sparingly soluble. * From strong alcohol lauric acid crystallizes only at 32° F. RAW MATERIALS USED IN MANUFACTURE OF SOAP. 29 Stearic acid. — Pure stearic acid crystallized from alcohol con- sists of nacreous needles or laminae, which melt at 156° to 156.5° F. to a colorless liquid, which on cooling solidifies to a white, fine, scaly, crystalline mass, lamino-crystalline on the fractured surface. By heating to 680° F. it commences to boil, with par- tial decomposition. "With a decreased pressure it distils without alteration. In distilling with superheated steam it apparently also passes over without alteration, but experience in the distilla- tion of fatty acids on a large scale has shown that a small portion is decomposed and passes over into solid hydrocarbons of the series C n H 2n + s .* At 11° G. (51.8° F.) its specific gravity is the same as that of water ; at higher, temperatures it floats upon water, expanding more quickly by heat than the latter. At low temperatures it is heavier than water, having a specific gravity of 1.01 at 32° F. Its specific gravity when melted at 156.5° F. is 0.8454. It is tasteless and odorless and not unctuous to the touch. It is insoluble in water, but freely soluble in hot alcohol. In cold alcohol it is even more sparingly soluble than palmitic acid. Forty parts of absolute alcohol dissolve 1 part of stearic acid ; in ether it dissolves freely. At 73.5° F. 1 part of benzol dissolves 0.22 part of stearic acid, and 1 part of carbon bisul- phide 0.3 part. The salts of stearic acid and the other non-volatile fatty acids are called soaps, the alkaline salts being soluble in water, while the others are insoluble or only sparingly soluble. By boiling stearic acid with aqueous solutions of carbonate of socla or potash, carbonic acid is expelled and stearates are formed. The alkaline salts in their purest state are crystallizable. Their behavior in water is also characteristic of the alkaline salts of other fatty acids. They are sparingly soluble in cold water, but when boiled with not too large a quantity of it they yield a clear solution, which, however, congeals to a turbid, viscid mass. With a large quan- tity of water they do not yield a clear solution, but a turbid fluid which, on shaking, gives a strong lather which remains standing for some time. The stearates are separated from their solutions by sodium chloride (common salt). The potassium salt can be * Benedict. Analyse der Fette und Waclisarten. Berlin, 1886, S. 11. 30 MANUFACTURE OF SOAP AND CANDLES. converted into the sodium salt by repeated treatment (" salting out") with common salt. The alkaline stearates are freely solu- ble in alcohol. On cooling the soaps generally separate from concentrated solutions as a jelly, which assumes, however, a crys- talline form after long standing. In ether and petroleum ether they are insoluble. Potassium stearate forms crystals with a fatty lustre, which dis- solve in 6.6 parts of boiling alcohol. By compounding its hot aqueous solution with much water the acid salt, which is insoluble in water, is precipitated in nacreous scales. Sodium stearate is very much like the potassium salt, and consists of nacreous laminae. The aqueous solution of ammonium stearate yields, on heating, ammonia, and is converted into the acid salt. The other salts of stearic acid can be obtained by precipitating aqueous solutions of sodium stearate or alcoholic solutions of stearic acid with the ace- tates of the respective metals. The stearates of calcium, stron- tium, and barium form crystalline precipitates. The magnesium salt is also crystalline ; it is almost insoluble in cold alcohol, but sufficiently soluble in hot alcohol to allow of its re-crystallization from it. The salts of the heavy metals are mostly amorphous, the lead salt being fusible without decomposition at 257° F. For the quantitative determination of stearic and palmitic acids, it is of importance to know that their insoluble salts are partially decomposed by washing. By washing, for instance, the barium salt, the barium passes into the solution, the residue containing free fatty acid, which can be extracted with alcohol. For a closer examination the fatty acids must, therefore, never be weighed in the form of their salts, but first be liberated from them. Chevreul distinguished, among the fatty acids obtained by the saponification of fats, one which he termed margaric acid, which, however, has been shown by Heintz to be a mixture of stearic and palmitic acids. For the manufacture of stearin candles the behavior of stearic and palmitic acids, when melted together, is of great importance. Heintz found that mixtures of fatty acids are analogous to many alloys of metals in showing a lower melting-point than their separate components. The following table shows the behavior of mixtures of stearic and palmitic acids : — RAW MATERIALS USED IN MANUFACTURE OF SOAP. 31 Composition of mixtures. Melting-point. . Manner of congealing. Degrees F. Stearic acid. Palmitic acid. 153.00 90 10 Crystalline scales. 149.5 80 20 Slender crystalline needles. 145.0 70 30 it a u 140.0 10 90 Beautiful large needles. 135.5 20 80 Very indistinctly needly. 134.0 50 50 Large-foliated crystalline. 133.0 40 60 (i it a 132.0 35 65 Non-crystalline, lustrous. 131.0 32.5 67.5 it a it 131.0 30 70 " " lustreless. Though the lowering of the melting-points decreases the value of the mixtures for the manufacture of candles, this disadvantage is more than counterbalanced by the importance of the other alterations the fatty acids undergo by being melted together. The pure acids are soft, of a loose structure, and very friable. By mixing them together they acquire sufficient density and hardness, so that they can be subjected to the pressure required to expel the oleic acid. The pure acids in congealing contract to such a degree that candles prepared from them have an unsightly appearance. A mixture of the acids being but slightly crystal- line to amorphous, candles manufactured from the semi-congealed mass are dense and non-crystalline. Candles from pure fatty acids are soft, opaque, friable, and lustreless ; candles from a mixture, hard, lustrous, and transparent. Of the oleic acid series the following occur in the fats : tiglic acid (C 5 H 8 2 ), hypogaeic, or physetoleic acid (C ]6 H 30 O 2 ), oleic acid (C 18 H 34 2 ), doeglic acid (C 19 H 36 2 ), and erucic acid (C 22 H 42 2 ). At an ordinary temperature these acids are partially solid and partially liquid, but they all melt at a somewhat increased tem- perature. In regard to the proportions of their combinations, they are similar to the acids of the first series. The most important of the second series is oleic acid. In a pure state it is liquid at an ordinary temperature ; it congeals at 39° F. to a hard, crystalline mass, which melts at 57° F. Its specific gravity is 0.898 at 50° F. In an entirely pure state it is a colorless, somewhat thickish, substance, without taste or smell, 32 MANUFACTURE OF SOAP AND CANDLES. and does not redden litmus paper. Oleic acid, in the solid state, oxidizes but slowly in the air • but when melted it rapidly absorbs oxygen, becomes yellow, and acquires a rancid taste and odor, and a decidedly acid reaction. It is not absolutely insoluble in water, very soluble in cold alcohol, and dissolves in all proportions in ether. By the addition of large quantities of water the greater portion of the acid re-separates from its solutions. It volatilizes with overheated steam, or in vacuo, without decomposition, but by itself it cannot be distilled at an ordinary pressure. Nitrous acid converts it into the isomeric ela'idic acid, a soft, opaque, crys- talline mass, without lustre, melting at 111° to 113° F. It is soluble in alcohol and ether, insoluble in water, and shows an acid reaction. At a temperature of 140° F. it absorbs oxygen, whereby it loses its power of congealing. Oxidized oleic acid is not converted into ela'idic acid. When heated with caustic potash oleic acid is resolved into palmitic acid and acetic acid : — C, 8 H 3 ,0 2 + 2K HO = C 2 H 3 K0 2 + C 16 H 3l K0 2 + 2H. Oleic acid. Caustic potash. Potassium Potassium Hydrogen acetate. * palmitate. The behavior of the salts of oleic acid, as regards their solu- bility in water, is similar to that of the salts of solid fatty acids, the alkaline salts alone being soluble ; all the other salts are, however, soluble in alcohol, and some also in ether, the lead salt belonging to the latter. The alkaline salts separate from their aqueous solutions by the addition of an excess of alkali, sodium chloride, etc. All the salts of oleic acid are softer than those of the solid fatty acids, and mostly fusible without decomposition. Sodium oleate (C, a H 33 Na0 2 ) can be obtained by crystallization from absolute alcohol. It dissolves in 10 parts of water at 53.5° F., in 20.6 parts of alcohol of 0.821 specific gravity at 55° F., and in 100 parts of boiling ether. The potassium salt forms a transparent jelly by far more freely soluble in water, alcohol, and ether than the sodium salt. The barium salt is a crystalline powder insoluble in water, and at 212° F. cakes without melting. By boiling alcohol it is taken up with difficulty. Lead oleate is a loose, white powder, melting at 176° F. to a yellowish fluid ; after cooling it is, however, rigid and brittle, and remains transparent. RAW MATERIALS USED IN MANUFACTURE OF SOAP. 33 Only two acids of the third group have thus far been found in the fats, viz., linoleic acid (C 16 H 28 2 ) and elaeomargaric acid (C l7 H 30 O 2 ). Of these linoleic acid alone is of any importance, its glyceride forming the principal constituent of linseed oil and very likely of other drying oils. It is a slightly yellowish oil, with a specific gravity of 0.9206 at 57° F., and does not congeal in the cold. It has a slightly acid reaction and is readily soluble in alcohol and ether. By nitrous acid it is not converted into elai'clic acid, like the actual oleic acid, but becomes only reddish and thickly fluid. It absorbs oxygen from the air more rapidly than oleic acid, and when exposed, in thin layers, to the action of the air, is first converted into a solid, resinous substance, called oxyoleic acid, and finally into a neutral body insoluble in ether. The barium and calcium salts of linoleic acid are soluble in boiling alcohol, and the calcium, zinc, copper, and lead salts also in ether. Most of these salts are amorphous ; the zinc combina- tion alone can be obtained crystallized. Of the fourth group only one acid has thus far been found in the fats, viz., ricinoleic acid (C 18 H 34 3 ). At 59° F. it is a thick oil with a specific gravity of 0.940, which congeals on cooling to from 20.75° to 14° F., and is miscible in all proportions with alcohol and ether. It cannot be volatilized without decomposi- tion. It does not absorb oxygen from the air ; by nitrous acid it is converted into a solid modification, ricinela'idic acid, which melts at 122° F. Most of the salts of ricinoleic acid can be obtained in a crystalline form, and, as regards their proportions of solubility, resemble those of oleic acid. The lead salt is soluble in ether and fuses at 212° F. In the examination of fats, titrations of the free fatty acids are frequently executed. The best indicator for the purpose is phenol- phthalein. The solution is prepared by dissolving 0.5 to 1 gramme of phenol-phthalein in 1 liter of alcohol. It has a yellowish color, and is reddened by the slightest addition of alkali in consequence of the formation of the corresponding salts. These salts are completely decomposed by weak acids, so that fatty acids in alcoholic solution can be sharply titrated with phenol-phthalein. Alcohols of the fatty group.- — As previously mentioned, three 3 34 MANUFACTURE OF SOAP AND CANDLES. alcohols take part in the constitution of fats : glycerin, cetyl alcohol, and cholesterin, the most important being glycerin. Pure glycerin (C 3 H 8 3 ) is a neutral, colorless, and inodorous liquid of the consistency of syrup, having a specific gravity of 1.27 at 59° F. It can be mixed with water and alcohol, and possesses a very sweet taste. Exposed to the air it absorbs as much as 50 per cent, of water. By evaporating an aqueous solution of glycerin in a water-bath some glycerin volatilizes with the aqueous vapor ; the residue cannot be obtained anhydrous even by drying at 212° F. On exposure to heat glycerin volatilizes in part, becomes dark, and decomposes, giving oif, among other products, a body characteristic of all glycerides, acrolein (C 3 H 4 0), the vapors of which are very irritating, attack- ing most violently the mucous membranes of the nose and eyes. In a current of superheated steam glycerin distils without altera- tion. It possesses great solvent power, dissolving the alkalies, alkaline earths, lead oxide, and salts, especially those which are known to deliquesce in the air. With sulphuric acid it combines to a bibasic acid, which is, however, very deliquescent and cannot be evaporated without decomposition even in vacuo; with other acids it forms similar combinations. It was formerly supposed that glycerin could not be crystallized, but, when quite pure and anhydrous, it crystallizes on exposure to a very low temperature, especially when agitated, as in railway transport. The crystals are monoclinic, perfectly colorless, and melt at 60° F. Cetyl alcohol (C 16 H 34 0) is a white crystalline mass, melting at 122° F. and boiling at 651° F. It is insoluble in water, but soluble in alcohol, and very freely so in ether and benzine. Cholesterin (C 26 H 44 0) crystallizes from chloroform in anhydrous needles of 1.067 specific gravity, which melt at from 293° to 294° F. Cholesterin is insoluble in Avater, very sparingly soluble in cold diluted alcohol, but freely so in ether, carbon bisulphide, chloroform, and petroleum. Its solutions turn the plane of polarization to the left. By careful heating it volatilizes without decomposition ; it is, however, best to distil it under decreased pressure. Glycerides. — The most widely distributed, and, therefore, most important glycerides are tristearin, tripalmitin, and triolein, most RAW MATERIALS USED IN MANUFACTURE OF SOAP. 35 fats occurring in nature being mixtures of them. Of further special importance to the soap-manufacturer is the glyceride of lauric acid, or trilaurin, or laurostearin as it is usually called. Trisiearinl {n tx n\ ^ 3 or, as it is briefly called, stearin, forms colorless, nacreous scales, which melt at 161° F., and con- geal at 158° F. to an indistinctly crystalline mass. By heating stearin, however, to at 7° above its melting-point, it congeals at 125.5° F. to a waxy mass and then melts at 131° F. But by again heating it a few degrees above the latter melting-point it reassumes its original melting-point at 161° F. Stearin is insolu- ble in water, sparingly soluble in cold alcohol and ether, but freely in warm ether and boiling alcohol. It is the prepondera- ting constituent of the tallows. Tripalmitin /p A K\ O3 or, as it is briefly called, palmitin, is contained in a preponderating quantity in the lards. It is best obtained pure from palm-oil. It consists of small, nacreous crystals, very sparingly soluble in cold alcohol, and somewhat more freely in boiling alcohol ; on cooling it re-separates, how- ever, in flakes. In boiling ether it is soluble in all proportions. When heated its behavior is very remarkable ; it melts at 123° F., but on further heating re-congeals, and then only melts again at 152° F. Laurin or laurostearin fr * T 3 r ^ (X forms slender, white L(C 12 H 2 ,0) 3 sj needles grouped in the form of a star or tree, which melt at from 111° to 115° F., and congeal at 73.5° F. They are insoluble in water, very sparingly soluble in cold alcohol, but more readily in boiling alcohol, and freely in ether. It is readily saponified by potash lye, forming a clear soap paste. When heated above its melting-point it is decomposed into acrolein and a solid body crystallizable from ether and alcohol. Triolein ,p X r\\ 3 or, as it is briefly called, olein, forms the principal constituent of non-drying oils. Pure it is a color- less and inodorous oil which crystallizes in needles at 23° F. It is insoluble in water, dissolves with difficulty in cold alcohol, 36 MANUFACTURE OF SOAP AND CANDLES. but more freely in hot alcohol, and is roiscible in all proportions with ether. Exposed to the air it darkens and becomes acid and rancid by the oleic acid gradually undergoing decomposition. Nitrous acid converts olein into ela'iclin which is isomeric with it. This crystallizes in laminae which fuse, according to Meyer, at 89.5° F., and, according to Duffy, at 100.5° F., and are almost insoluble in alcohol, but freely soluble in ether. As regards the proportional quantities of stearin, palmitin, and olein occurring in the fats, we would remark, that a fat is the more solid the more it contains of the first two, and the softer the greater the preponderance of the last. Saponification of fats. — By saponification was originally under- stood only the chemical process which takes place in boiling fats with strong bases whereby glycerin and fat acid salts are formed ; but at the present time the term is applied to every reaction by which fats (even without the co-operation of bases) are resolved into glycerin and fatty acids. To understand the process of saponification we must consider that all glycerides are a variety of ethers, and as such possess the power of splitting by the absorption of water into their generators, i. c, into glycerin and an acid. Therefore, for instance, (C ]8 H 35 0)3 3 + ^> u ~ IV - + ^i8 H 3 5lI u - Tristeariu. Glycerin. Stearic acid. This splitting of the glycerides is called saponification. It already takes place with water alone, but only at a comparatively high temperature. It is facilitated by adding to the water a small quantity of a base or of an acid ; but it is most readily accomplished by using together with the water a sufficient quantity of a base (potash, soda, or lime) to fix the acids formed, whereby the salts of these acids result, which are familiarly known as "soaps." The process is represented by the following equations : — (C 18 H 3s O) 3 U s + 3KOH = H 3 3 + 3C 13 H, 5 qO. Tristeariu. Caustic potash. Glycerin. Potassium stearate i (C I8 H 35 0) 3 u » + 30aH 2 O 2 = 0^'3^5O 4- 4 Ca U ** Tristeariu. Caustic lime. Glycerin. Calcium stearate. RAW MATERIALS USED IN MANUFACTURE OF SOAP. 37 The splitting of the glycerides can further be effected by sul- phuric acid, whereby first glycerinsulphuric acid is formed and perhaps other sulphuric acid combinations of the acids contained in the fats (sulphostearic acid, sulpholeic acid, etc.). We would here remark that ammonia, the behavior of which is otherwise analogous to that of the alkalies, does not act in the same manner upon the fats. By shaking a fat oil with liquid ammonia an emulsion is formed ; by exposing this to the air the ammonia volatilizes in a short time, and the oil separates without alteration. The oil is also obtained unaltered when a quantity of dilute acid corresponding to that of ammonia is added to the mixture. This proves that ammonia and fat do not form combi- nations by a simple mixture. But, by allowing ammonia to act upon fats in closed vessels, chemical combinations result, ammo- nia soap and the amide of the fatty acid being formed. On the splitting of the natural glycerides into fatty acids and glycerin depends their utilization for the manufacture of soap and candles and the fabrication of plasters. By the latter are gene- rally understood the lead oxides of fatty acids, though the term is also applied to combinations of these acids with other heavy metallic oxides obtained by precipitating soap solutions with metallic solutions. Manufacture of stearic acid. — Though Braconnot and Simonis, as early as 1818, applied the separability by pressure of the fats and oils into a liquid and solid constituent — olein and stearin — for the purpose of obtaining the more solid stearin, the first idea of utilizing this property of the fats and oils for industrial pur- poses occurred to Gay-Lussac and Chevreul, to whom, in 1825, a patent was granted. Their specifications are very interesting, as they embody nearly all the scientific principles applied at the present time to the fabrication of fatty acids, even the saponifi- cation by means of acids, which was practically carried into effect only twenty years later. Their process was, however, a failure, being too much like the methods employed by the chemist in the laboratory, and too complicated for technical purposes. Saponification was to be effected by means of alkalies, and the decomposition of the resulting soap by hydrochloric acid. The manufacture was placed upon a practical and economical 38 MANUFACTURE OF SOAP AND CANDLES. basis by the introduction by de Milly and Motard, in 1831, of the use of lime in place of alkalies for the saponification of fats, and that of sulphuric acid for the decomposition of the lime-soap formed. Stearic acid, as a material for candles, was first used by de Milly in 1831, in Paris, on the Barriere de l'Etoile, and hence the candles were called " Bougies de VEtoile" and, also, " Milly candles" The saponification of fats by means of a high pressure was patented by Runge as early as 1835, but was first introduced into practice by de Milly, who, in 1855, patented an apparatus suitable for the purpose, which is called an " autoclave." The fact that the neutral fats are decomposed by concentrated sulphuric acid in a similar manner as by caustic alkalies was known to Achard of Berlin in the year 1777. It was scientifi- cally investigated, in 1836, by Frerny, and finally practically applied in 1840 by Gwynne. The distillation of the fats was proposed by Gay-Lussac and Chevreul as early as 1825, but was not industrially applied until 1841, when Dubrunfaut introduced the process on a large scale. Nearly at the same time Wilson and Gwynne took out patents for a combination of both processes — decomposition with sul- phuric acid, and subsequent distillation. To the researches of Tilghman and Bertholet we owe the in- teresting and important fact that water at a high temperature (356° F.) and a pressure of 10 to 15 atmospheres is capable of splitting neutral fats into their constituents. It still remains to be mentioned that when, according to the researches of L. Kraft and Tessie du Motay, a neutral fat is heated with anhydrous chloride of zinc, a complete incorporation of these substances takes place between 302° and 392° F. ; and by continuing the heating for some time and washing the materials with warm water, or, better, with water acidulated with hydrochloric acid, there is obtained a fatty matter, which, on being subjected to distillation, yields the corresponding fatty acid, while only a small quantity of acrolein is formed. The chloride of zinc, becoming soluble in the water used for washing, may be recovered by evaporating the fluid. The yield of fatty acids by this process is the same as that obtained by the use of sulphuric RAW MATERIALS USED IN MANUFACTURE OF SOAP. 39 acid, while the fatty acids also agree as to their physical proper- ties. The quantity of chloride of zinc required amounts to 8 to 1 2 per cent, of the fat. We will now proceed to give a description of the various methods of saponifying the fats. 1 . Saponification of the fats by means of lime, a, under ordinary atmospheric pressure. The process upon which the technical sepa- ration of stearic acid is based is the same as for soap, and com- mences with the displacement of the glycerin by means of lime. The resulting lime-soap is then decomposed by sulphuric or hydro- chloric acid in order finally to effect the separation of the stearic and palmitic acids by pressure. For saponification the tallow or palm-oil, etc., is brought into a vat lined with lead, or into a cemented brick reservoir, the former being about 5 \ feet wide and 2^ feet deep for 1100 lbs., and the latter having a volume of about 406 cubic feet, which suffices for 4000 lbs. of tallow, 600 lbs. of lime, and 4000 lbs. of water. To prevent the lime-soap from acquiring a yellow color iron vessels and lime, containing iron, have to be avoided. Fig. 1. Fi, funnel for filling trays ; E, wooden plug ; F, pipe from reservoir. The fatty acids having been thoroughly freed by repeated washing from gypsum, sulphuric acid, etc., are allowed to rest for some time in a melted state, to give the water a chance to completely separate. The fatty acids are then drawn off into trays to congeal or crystallize. RAW MATERIALS USED IN MANUFACTURE OF SOAP. 43 The flat, rectangular trays C, Figs. 3 and 4, of heavy tinplate, are provided with a spout, and have each a capacity of 4 J lbs. of fatty acid, a greater capacity being disadvantageous on account of too slow cooling. The trays are placed upon a wooden frame- work, A, bound by transverse bars of iron, B, which support the trays at the same time, in such a manner that the spouts are arranged alternately, and one tray projects above the other. The melted fatty acids are now conducted from the reservoir through the pipe F into funnels D, which are provided with a wooden plug, E, for stopping them. The upper rows of trays being filled, the mass runs over through the spouts into the next row, and so on in zigzag, until all the trays are filled. The wooden plugs E are then inserted in the funnels D. The trays are kept in a con- venient room having a temperature of about 77° to 86° F. until the fatty acids assume a crystalline form or granulate. At this temperature oleic acid does not solidify, and forms a mother-lye, which contains, besides impurities, a portion of palmitic and stearic acids in solution. To eliminate the oleic acid, etc., retained between the crystals of the solid mass, and to convert the, at first, smeary and dirty- brown substance into a white, dry, and solid one, the cakes of fatty acid are taken from the trays and subjected, first, to cold and then to warm pressure. This is the more readily accomplished the more crystalline the cakes are. To subject the mass at once to warm pressure would cause loss by stearic acid, etc., passing into the oleic acid. For cold pressing an ordinary hydraulic press is used, the cakes being enveloped in woolen cloths or horse-hair mats. The cakes, taken from the cloths after pressure, are sorted out so that those not completely freed from oleic acid, which is recognized by their dirty color, can be once more subjected to cold, and the rest to warm pressure. Before subjecting the cakes to the second warm pressure, they are generally thrown into a vat and melted down by blowing in steam for several hours. After settling, the fatty acids are drawn into the previously-mentioned trays and allowed to cool at a tem- perature of about 86° F. When the cakes have assumed a crys- talline structure they are cut up into lumps and ground to a mealy 44 MANUFACTURE OF SOAP AND CANDLES. powder by means of a rasping machine, worked usually by steam. This powder is wrapped in woolen cloths, or horse-hair mats, and submitted to warm pressure. A special hydraulic press is required for this purpose, the construction of which has undergone many changes since the introduction of the stearin candle industry. Formerly such presses consisted of a trough, in which the cakes were pressed, a press-cylinder, and cast-iron plates, which, before every operation, were dipped in hot water and placed between the cakes of fatty acid, which, of course, consumed much time. At the present time hollow press plates heated, by steam are used. Fig. 5 shows a horizontal hydraulic press with plates which can be heated either by steam or hot water ; with the use of the latter the temperature, which is best kept at from 95° to 104° F., can be better regulated. Fi is 1 ,a CO o "3 >> s3 2 03 Ji CO O 03 CO CO S3 a 03 > 'cc a 03 a CO CO ce 2 a CD O o 1 03 be a sd 3 CO CO 33 2 a 03 CU bo a a S a a CO a -a 3^ cr 1 s3 •~ a. 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"3 a 03 03 :- 03 S3 1 1 ! a p o 03 >1 I 1 a a a S-r a' > o u Id -5 a 1 — 1 03 a n ' >.bo 1 * °ca a>-o a r>. a CO CO 03 03 •a !2 CO co a ?g ^ CO co CO CO acid ipeci y. th 1C SOI 10 sp ravil 2 ^ a X 03 13 "3 -o CO 5 ? a -a a. 03 3 3 a S3 q >% a sJ X ft2 a CO CO CO S3 a ^ 3 t>^ a CO 33 a a ".H-um bo TS S3 -a CO S3 2 ■a' CO a "" CO — T3 s so 2 s <~ 2 'a 33 a s .H 03 2 S3 '3 2* a .2* •a 13 5 — T w - * a a o -3 33 a 2 fe si o a 5 a- 2 "3 a - 3 '3 .2 si a a a 'a 2 a a 3 a a S3 ^ _ be » © a — CO CO -< S co Xi CO D - : -^ CO -* CO CO .2 o o «d S* .d co -a CD CO a a a S" _. "5 -n " - *- -a co u > re » bo "3 a? a CD a s3 1 1 T3 03 3 a a 33 1 ./a .S 2 2 a" a a 2 a .a C "3 •3® a a 3 -a a a 2 S3 a a 33 bo CO Ch ■a CO -3 bo 3o >. ft CO CO Nitric acid of 1.220 specific gravity. .a ■/} "a a P 03 a o3 1 1 o "3 -a CD -3 03 CD a S3 1 CO "£ a a 3 -3 3 3 1 a >> a Is > o a a s? T3- a a S3 1 bo co >> CO ■3 bo >. ft CO ft Nitric acid of 1.180 specific gravity. .d '3 V 03 03 a s3 1 1 , a 03 . & 03 o be—" S" 3 1 a >. a .S bo O a 1 a a "3 a 30 a a_j ^» 03 1 bo cc >, a T3 >» a- CO ; - a to a a — i a a t»» huri f 1.6 cific vity. a bl be a a a 1 a I 1 a > 12 a a a a a > 'ce a Sulp acid o spe gra a a 0j *3 o ■ o i 1 a 03 a 2 a "^ a '3 a a a d 3 -3 a 3 a a si ft 5 ft -3 -a •'- bo ft ^ CO CO a £% * - 2 ~ rC *•- W b. Ji 03 Id 03 13 a a a ." CD - a a > a a a a CO a 3 -a a CO 03 & & 6i;& £ "* a «> 03 3d & "a & a Sulp acid o spe gra' a a 03 bo S> 3d -3 •a 03 I* la -3 33 bo -r a -3 a S a bi -3 bi ^3 a 3 -3 ■a a a 2 33 co ft u 3 ft a !>• >> a ^3 Sulphuri acid of 1.4 specific gravity. ^3 a a CO > .a T3 *!* a 03 03 t-i 03 S s3 1 1 1 '3 p a a a 1 a £ a a a a a a a "3 a 2 33 a ft t-i 3 bo CO -a bo 3c ■3 >> ft X ft © & , ( Caustic soda of 1.3 specific gravity. o 03 03 *e8 £ s3 -a a s3 M ,a 03 3 "3 d co > 3 03 ^1 CD a a a S3 a a ^& -a a ©■a a 3 Ji CO -3 -3 a a 03 >> 3 >> 3 •a a a 3 ^ ^3 a 2 33 a a S3 P. CO 'a CO CO CO 93 0=1 «* •a •a CO XI • • • • • • • • • • • 'a • o 03 ►J M o "3 0> > '3 o 2* '3 so a '3 03 ft '3 a. O "o a a S3 CO 'o a CO 'a ft Q '? ■a 03 a CO a '3 a <2 CO "3 'a a "3 J3 CO ca ^d a si 'a a > -a s t- 03 a a a S3 a S3 a * a O a < M Ph ^5 in o ffi 3 J 25 £ O 10^5 MANUFACTURE OF SOAP AND CANDLES. Foreign admixtures with which the fats or oils may be con- taminated or adulterated are determined with greater ease than additions of other fats or oils. The most frequent contamina- tions are water and sand (dirt). To determine the first, heat 40 to 50 grammes of the fat under examination in a tared beaker glass at 230° F., first for one hour with occasional stirring, and then for two hours, without stirring, at 247° F. The difference in weight shown by the fat thus dried as compared with the original sample is the content of water. To determine the content of dirt, melt the dried fat in a beaker glass, then filter through a tared filter, wash the latter with hot benzene and dry it at 176° to 194° F. The increase in weight of the filter gives the dirt contained in the fat. Any moisture of the filter, after drying at the above temperature, is due to a small amount of glycerin. In this case the filter is extracted with alcohol and again dried. In consequence of incomplete purification after refining, the fats may contain sulphuric acid, alkaline carbonates, alum, and lead. Sulphuric acid is found by vigorous shaking of the oil with distilled water, and, after allowing the aqueous fluid to settle, compounding it with barium chloride. A white precipi- tate indicates the presence of sulphuric acid. Alkaline carbonates are determined by shaking the oil with water and testing the latter for alkaline reaction with litmus paper. The presence of alum is shown by shaking the oil with water containing some nitric acid, evaporating the aqueous solution, and compounding with ammonia. A white precipitate proves the presence of alum. The fat oils are frequently adulterated with cheaper fat oils, principally resin-oil and mineral oils. The most reliable method of showing their presence is the saponification process first recom- mended by Thompson, i. e., saponification of the oil under exami- nation, mixing the soap formed with sand, drying the soap, and extracting with petroleum ether. The method proposed to shake the liquid soap directly with petroleum ether and to separate the latter from the soap solution by means of a separatory funnel, cannot be recommended. Finkener* declares the last method entirely useless when the oil contains less than 10 per cent, of * Mittheilungen aus der Koenigl. techn. Versuchsanstalt, Berlin, 1886, S. 13. EXAMINATION OF FATS AND FAT OILS. 103 non-saponifiable oil, and uses alcoholic soda lye for saponification, while Thompson recommended alcoholic potash lye. Finkener prefers soda, because potash-soap is more difficult to dry than soda-soap, and proceeds as follows : — Dissolve 35 grammes of Natrium hydricmn pwrum in 85 cubic centimetres of water and pour the hot solution into 730 grammes of boiling hot alcohol. Bring 10 grammes of the oil to be exam- ined into a flask of 300 cubic centimetres' capacity, add 50 cubic centimetres of the alcoholic soda solution, boil the whole for 15 minutes in a water-bath and compound with 5 grammes of sodium bicarbonate for the conversion of the excess of soda used into carbonate. Pour the solution upon 200 grammes of pure dry sand in a metal evaporating dish and heat in a water-bath, with constant stirring, until the odor of alcohol has entirely dis- appeared. The warm mass is then brought into a glass cylinder of 500 cubic centimetres' capacity and provided with a stopper, and, after cooling, 300 cubic centimetres of petroleum ether, with a boiling point below 212° F., are added and the whole is thor- oughly shaken for some time. The ether is then filtered off through a dry filter into a dry flask and 150 cubic centimetres of the filtrate are distilled in a still. The residue from the still is brought with a little petroleum ether upon a watch-crystal and dried in a water-bath until the petroleum ether disappears. In examining commercial oils in the manner described, 0.5 to 3 per cent, of non-saponifiable residue is obtained even if there be no reason for suspecting adulteration. An intentional addition of mineral-oil can, therefore, be only assumed when more than 5 per cent, of non-saponifiable matter is found. Whether the residue consists of resin-oil or mineral-oil is recog- nized by treating it with a mixture of 10 volumes of alcohol of 0.8182 specific gravity at 60° F. and 1 volume of chloroform. Resin oils dissolve, according to Finkener's* investigations, at 73.5° F. by shaking with 10 times their volume of this mixture, while mineral oils with a high boiling point do not dissolve even if shaken with 100 times their volume. Demski and Morawskif * Mittheilungen aus der Koenigl. techn. Versuchsanstalt, Berlin, 1885, S. 160. f Dingler's Polytechn. Jour. 258, S. 39. 104 MANUFACTURE OF SOAP AND CANDLES. treat the oily residue with acetone. If it dissolves in an equal volume of acetone, resin-oil, or resin-oil compounded with a little mineral-oil, is indicated ; if a portion remains undissolved, the sample consists of mineral-oil or mineral-oil confounded with a little resin-oil. If the quantity of non-saponifiable oil in a fat amounts to more than 10 per cent., Finkener seeks to establish the fact by the de- termination of the alkali required for saponification, therefore by simple titration. " The natural fluid fats contain over 50 per cent, of olein, and as palmitin, olein, and stearin require 20.84 per cent., 19.00 per cent., and 18.87 per cent, of potassium hy- droxide for saponification, an average of about 19 per cent, will be necessary. To test the oils in this respect, dilute sulphuric acid (124.2 grammes of S0 2 to the litre), an alcoholic solution of potash of which 50 cubic centimetres are equivalent to 13 cubic centimetres of sulphuric acid, and a solution of phenol-phthalein in 100 parts of alcohol are used. The potash solution is prepared by dissolving 55 parts by weight of Kalium hydricum purum in 85 parts by weight of water and pouring the hot solution into 730 parts by weight of boiling hot absolute alcohol. The next day the clear solution is drawn off from the sediment and diluted with 90 per cent, alcohol to the desired concentration. Ten grammes of the oil, weighed in an Erlenmeyer flask of 300 cubic centimetres' capacity, are boiled with 50 cubic centimetres of potash solution for 15 minutes, with frequent shaking for the first few minutes. Saponification proceeds in this manner with- out jolting of the fluid. " After adding 5 drops of phenol-phthalein, the liquid is titra- ted with sulphuric acid to somewhat above the point of decol- oration, the carbonic acid expelled by boiling, and the red coloration restored by titration with the potash solution. The recognition of the change of color of the phenol-phthalein pre- sents no difficulty, even if, in the presence of dark-colored mineral oils, the saponified sample assumes a brown color." This simple method would be an excellent one if the fats and fat oils consisted only of palmitin, stearin, and olein. But we have a number of fats with a saponification equivalent materially differing from that assumed above, especially cocoanut-oil and EXAMINATION OF FATS AND FAT OILS. 105 palm-kernel oil, which, on account of their percentage of lauro- stearin, fix a considerably larger quantity of potassium hydrate, and the oils from the cruciferce, which, on account of their per- centage of erucic acid, fix a smaller quantity. Finkener's method is, therefore, available only for a limited number of oils. The presence of resin in fats is readily shown by its solubility in alcohol and soda solution. By repeatedly heating the sample of fat with 70 per cent, alcohol, the resin passes into solution. After precipitating it with water, the precipitate is concentrated by heating, and, if necessary, by the addition of some hydrochloric acid ; it can then be readily recognized as resin by its appear- ance, odor, etc. Barfoed heats the fat with a soda solution pre- pared by dissolving 1 part of crystallized soda in 3 parts of water and adding 7 parts of 30 per cent, alcohol (2 volumes of alcohol of 93 per cent, and 5 volumes of water). The resin passes into solution and is separated by acidulating and heating. As the commercial fats contain more or less free fatty acids, the above methods are not available for the quantitative determi- nation of resin. For this purpose the fat must first be saponified and the quantity of resin determined as described later on for the determination of resin in soaps. The presence of free fatty acids in oils can be readily detected. A very simple method is given by Wiederhold.* By pouring the oil to be examined over cuprous oxide in a white glass, the layer next to the cuprous oxide assumes a green color if the oil contains acid. The appearance of the reaction is promoted by moderate heating. To test the neutrality of the oils Allairef shakes them with a solution of sodium bicarbonate in water. If the oil separates in shining globules it is neutral, but if it becomes turbid and a partial saponification takes place it contains free fatty acids. For the quantitative determination of fatty acids, Mayer dis- solves 2 to 3 grammes of fat in 20 cubic centimetres of ether, compounds the solution with 10 cubic centimetres of alcohol and some solution of phenol-phtalein, and adds, according to the con- * Dingler's Polytechn. Jour., 217, 314. f Octave Allaire, Notice sur les huiles neutres raffinees, p. 11. 106 MANUFACTURE OF SOAP AND CANDLES. tent of acid, T \ or j- normal lye, until the liquid assumes a red coloration. Aqueous potash lye is preferable to the alcoholic, on account of the constancy of its titer, which constantly changes in the alcoholic solution, and must, therefore, always be deter- mined anew before each series of experiments ; on the other hand, the fat readily separates from its alcoholic solution by the addition of aqueous lye, and has then again to be brought into solution by heating in a water-bath. With an alcoholic-ethereal solution two layers are formed, and the reaction must be carried on to the end with vigorous shaking after each fresh addition of lye.* Titration does not give the per cent, by weight of the free fatty acids contained in the fat, but only the quantity of alkali required for the neutralization of a determined weight of the sample. For oils this is generally satisfactory, the number of cubic centimetres of normal lye required for the neutralization of 100 cubic centimetres of the sample being given. The quantity of glycerin contained in a fat is determined in the usual manner, by saponifying the fat with alcoholic potash or soda lye, expelling the alcohol by evaporation, dissolving the soap in water, adding dilute sulphuric acid and boiling mode- rately until the fatty acids have become entirely clear. The mass is then allowed to cool, and, after filtering the liquid containing glycerin from the congealed fatty acids, the latter are once more boiled in water, allowed to congeal, and the filtered wash-water is united with the first filtrate. The latter is exactly neutralized with sodium carbonate and then evaporated to dryness in a water- bath. The residue consisting of sodium sulphate and glycerin is treated with alcohol, which leaves the sodium sulphate undis- solved. The filtered alcoholic solution is evaporated, the residue again treated with alcohol, and the filtered solution evaporated in a platinum dish in a water-bath. On account of the volatility of glycerin at 212° F., the num- bers obtained by the foregoing process are always too low. The most reliable process, and one which is available for all cases, is * Benedikt. Analyse der Fette u. Wachsarten, S. 93. EXAMINATION OF FATS AND FAT OILS. 107 the determination of the glycerin by oxidation with potassium permanganate. When glycerin in a strongly alkaline solution is oxidized at an ordinary temperature with potassium permanganate, 1 molecule of glycerin yields quantitatively exactly 1 molecule each of oxalic and carbonic acid — C 3 H 8 3 + 30 2 = C 2 H 2 4 + C0 2 + 3H 2 0. Upon this is based the determination of glycerin by Benedikt and Zsigmondi,* the principle having been first established by Fox. The fat is saponified with calcium hydrate and entirely pure methyl alcohol, the residue dissolved in hot water, and the soap decomposed with dilute hydrochloric acid. It is then heated until the fatty acids have separated clear. With fluid fats it is advisable to add some hard paraffin in order to congeal the fatty acids floating on top during the subsequent cooling, which is effected by placing the dish in cold water. The fluid is then filtered into a capacious flask, neutralized with potash lye, and 10 grammes of caustic potash are added. 5 per cent, solution of potassium permanganate is then added at an ordinary tempera- ture until the fluid is no longer green, but assumes a blue or blackish coloration. It is then heated to the boiling point, whereby manganese peroxide is separated and the fluid becomes red ; as much aqueous sulphurous acid is then added as is required for complete decoloration. It is then filtered through a smooth filter of sufficient size to receive at least one-half of the entire fluid, and thoroughly washed with boiling water. The last wash- waters are frequently rendered turbid by some manganese per- oxide ; this turbidity disappears, however, by the action of the sulphurous acid liberated during the subsequent acidulation with acetic acid. The fluid is then heated to nearly the boiling point and precipitated with calcium chloride or calcium acetate. As, besides calcium oxalate, the precipitate contains always some silicic acid and frequently gypsum, it cannot be considered, after calcining, as pure calcium carbonate, nor as calcium oxide. The determination of the calcium oxalate contained therein is * Cheraiker Zeitung, 9, S. 975. 108 MANUFACTURE OF SOAP AND CANDLES. best effected by titration, either with potassium permanganate in acid solution or by alkalimetry after calcining. For the latter purpose the calcined precipitate is dissolved in about half-normal solution of hydrochloric acid, titrated back with about half- normal soda lye with an addition of dimethyl-aniline orange as an indicator. The titer of the hydrochloric acid is generally fixed for sodium carbonate ; 106 parts of sodium carbonate correspond to 92 parts of glycerin. In regard to the above process Ave would remark that methyl alcohol is used for the saponification of the fats instead of ethyl alcohol, because the latter, at certain concentrations and with a determined percentage of alkali in the solution, is converted by potassium permanganate into oxalic acid. This creates errors which are the greater the more alcohol is retained by the soap in drying. By repeated evaporation and renewing of the water to expel the last traces of alcohol, a portion of the glycerin would also be lost. The fluid subjected to oxidation contains besides glycerin all the soluble fatty acids ; by oxidation with potassium permanga- nate, according to the above process, they yield, however, neither oxalic acid nor another acid which can be precipitated by lime in acetic acid solution, so that their presence does not influence the determination of the glycerin. Whether an oil obtained by extraction is free from carbon bi- sulphide can, according to O. Braun, be readily recognized by stirring about 30 parts by weight of lye of 40° B. under 60 parts by weight of oil, and allowing the soap formed to stand in a warm place for one hour. If the oil is badly purified, the soap is dark green and of a bad odor, which, however, disappears in time (weeks or months), leaving the soap externally faultless. FATS, FAT OILS, ETC. 109 CHAPTER V. FATS, FAT OILS, FATTY ACIDS, AND RESIN USED IN THE FABRICATION OF SOAP. According to their derivation, the fats are generally divided into animal and vegetable fats and oils. We commence our de- scriptions with the Fats of Animal Origin. Tallows. — Under this collective term are understood the masses of fat found in abundance in the abdominal cavity, around the kidneys, etc., of the ruminantia, especially of those which have been fattened. In commerce a distinction is made between beef tallow, derived from oxen, cows, and calves, and mutton tallow, from sheep and goats, the latter being firmer and whiter, though otherwise there is no material difference. Besides, the firmness of the tallow from the same variety of animals is not always alike ; it depends on the race, age, and especially on the food of the animal. Animals fed upon dry food furnish the most solid tallow, that of those pastured being less so, and that of those fed upon swill very soft. The crude tallow as furnished by the butchers is enveloped in very thin cellular tissues and more or less contaminated with particles of skin, blood, etc. If kept for several days, these par- ticles become decomposed and putrefy. It is necessary, therefore, especially in summer, to keep the tallow in a cool place or at once to separate it from the membranes by rendering. Rendering is effected either by the dry or the wet process. For the first the tallow is cut up and the membranes enveloping it torn asunder by the application of heat ; by the second process the tallow is boiled with dilute acids or alkalies which, dissolve the cell substance. 110 MANUFACTURE OF SOAP AND CANDLES. Dry rendering is the older method. The fatty tissues are cut into small cubes, placed in a copper over an open fire, and ex- posed to a heat exceeding that of boiling water. A small per- centage of water is frequently added, especially in summer, when the tallow has lost much of its natural moisture by evaporation. In the heat the membranes are destroyed and the melted tallow runs out, the membranous substances collecting on the top. These are removed and pressed so as to free them from fat. The solid matters — now called greaves or cracklings — form flat cakes and are sold as food for dogs, manure, or for use in the manufacture of lubricants and of ferrocyanide of potash. The melted fat is passed through a sieve into another suitable vessel and washed with boiling water. The impurities settle down with the water and the fat is drawn off into tubs and allowed to cool. This process has been in practice for a long time, and, notwithstanding its many inconveniences, is so still, especially in small establish- ments. Sometimes a still higher temperature is applied in order to cause the residuum to undergo a roasting, thereby trying to obtain a greater yield of pure tallow. In general, though, this method remains imperfect, and a larger or smaller loss of tallow is sustained, much remaining in the tissues, which are but imper- fectly opened by this operation, and become so hard that they yield the tallow under the press with difficulty. Besides, it is an impossibility to obtain an even temperature in the copper, it be- coming too high on the bottom to the detriment of the color and quality of the tallow. And furthermore the odor of the gaseous and other vapors developed from the animal substances during melting is so disgusting that from a hygienic standpoint this method of rendering has to be condemned. This disagreeable odor is more readily removed by the appli- cation of steam in lieu of an open fire, but it is only a slight im- provement in other respects, because the temperature remains too low, and besides, by the immediate contact of steam with the fat, the membrane is converted into glue, from which the tallow can be separated only with great difficulty. For this reason Appert proposed to render the tallow with one-third of its weight of water at 239° to 266° F., but even by this method the tallow is FATS, FAT OILS, ETC. Ill not completely rendered out, especially if the raw material is not sufficiently comminuted. By destroying the cells enveloping the fat as much as possible before heating, the rendering process is effected at quite a low temperature, the fat and membranous particles separating readily at 212° F. Several mechanical contrivances have been con- structed for this purpose and are used in the manufacture of mar- garin, it being absolutely necessary in this branch of industry to obtain a tallow as pure as possible and uninjured by the action of a higher temperature ; frequently the tallow is rendered at less than 212° F. The destruction of the cells enveloping the tallow has also been attempted by the addition of chemical agents, this method having the further advantage that the odorous substances combine with the chemical agent, or are destroyed. D'Arcet was the first to recommend dilute sulphuric acid for this purpose. Bring 50 pounds of dilute sulphuric acid into the copper, then add grad- ually 1000 pounds of the comminuted fat divided into four equal portions, and finally 150 pounds of water previously compounded with 5 pounds of sulphuric acid of 60° B. The mass is then heated. By the action of the sulphuric acid, which partly dis- solves and partly decomposes the membranes, the process of ren- dering even large quantities of tallow is finished in 1J to 2 \ hours. D'Arcet originally proposed the addition of acid for ren- dering over an open fire, but it is also available for steam render- ing, which is now employed in all large establishments. In most rendering establishments, not working with a closed apparatus, open wooden vats lined with lead, and direct steam are employed. For 100 pounds of tallow 20 pounds of water and 1 pound of sulphuric acid of 6Q° B. are used, and steam of a pressure of 1 to 2 atmospheres is introduced. Another very suitable process consists in pouring sulphuric acid of 4° to 5° B. over the crude tallow as delivered by the butchers and loading it with boards and stones so that the sulphuric acid stands over the fat. After four or five days the acid is drawn off through a faucet in the bottom of the vat. The tallow is then rendered by the introduc- tion of direct steam, the process being quickly accomplished, since 112 MANUFACTURE OF SOAP AND CANDLES. the cells have been partly destroyed by the acid. The greaves, which still contain tallow, are again acidulated and rendered out. Evrard has proposed to mix and warm 300 parts of commi- nuted tallow with caustic soda lye (made of 1 part of calcined soda dissolved in 200 parts of water). The odorous substances combine with the soda and remain in the lye dissolved, while the pure fat is separated. Though the Societe d' Encouragement of Paris examined this process and declared it an improvement, we prefer rendering with sulphuric acid. Many attempts have been made to render innocuous the disa- greeable vapors developed during rendering. The simplest method is to conduct them into a boiler fire. The idea originated with d'Arcet, who, in 1834, applied it to dry rendering. For this purpose it is, however, but little adapted, since the closed apparatus required impedes the necessary stirring ; but it can be utilized in steam rendering. The most thorough investigations in reference to the destruction of the developing fetid odor were made by Grodhaus and Fink. The melting vat was provided with a well-fitting cover. In this cover was a hole three inches wide over which a tin pipe was fixed and carried to a contiguous boiler fire. The contents of the melting vat consisted of crude tallow, first and second quality mixed, and the requisite quantity of sulphuric acid. As the vapors developed in the melting vat they were easily drawn through the tin pipe into the flames with- out extinguishing the fire. They left the opening of the chimney without the least smell, proving that the fetid-smelling products had been destroyed. Experiments were also made to conduct the vapors under the grate of the fire-place, but it became very soon manifest that they extinguished the fire, so that this experi- ment was abandoned. Among the many new inventions for rendering tallow, etc., over an open fire in a manner to avoid the offensive odors arising from the operation, that invented by Vohl is perhaps the most successful. Fig. 17 represents this apparatus. It consists of the cast-iron caldron A, lined with lead, the cylindrical head-piece B, and the cover C, with the mica plate D ; another mica plate is in the door E, both serving for observing the processes in the FATS, FAT OILS, ETC. 113 interior of A. At night a light is placed over the mica plate in the lid. The tallow is introduced through the door E, which also serves to close hermetically the cast-iron head-piece B. After rendering is finished the tallow is discharged through the faucet F and the acid liquid through the faucet G, while the greaves remaining upon a perforated plate in the caldron are removed through the door E. The gases and vapors developed during rendering in A pass through the pipe J into the condensing box K. The latter is closed with the cover L, provided with sand-joints at M. Fig. 17. Vohl's Rendering Apparatus over an open fire. In the interior of K are oblique scaffolds covered with decom- posed lime. The box itself is of wood saturated with asphaltum or tar. The water condensed in it runs off through the pipe X, the escape of gases being prevented by the curvature of R forming a trap. The gases and vapors not condensed in K pass through the 114 MANUFACTURE OF SOAP AND CANDLES. pipe Q into the condenser P, which is lined with lead and filled with coke or pumice-stone saturated with sulphuric acid. The liquid collected here passes through the pipe Q to the discharge- pipe R. The non-condensed gases, etc., are finally conducted through the pipe S into the channel T, which leads into the ash-pit U under the grate of the fire-place H. The non-condensed gases, etc., being almost completely freed from aqueous vapors by passing through the condensers, can be unhesitatingly admitted under the grate without fear of disturb- ing the draught. The ash-pit U is closed with an iron door, whereby a strong draught is produced which sucks all the gases from the apparatus under the grate. The gases of combustion escape to the flue V, which leads to the chimney. An apparatus for rendering tallow by steam, invented, if we are not mistaken, by Lock wood & Everett, of New York, is shown in Fig. 18. Its principal advantage consists in the com- plete destruction of the noxious vapors and in the safety from explosions, as the fat in the digester melts very gradually. The apparatus consists of two parts, a boiler or digester and a furnace for burning the developed gases and vapors, both being connected by the pipe J. The digester, which receives the fat to be rendered, consists of the steam-tight cylindrical boiler A, sur- rounded by the jacket B. To secure greater solidity, as the digester must stand a hy- draulic pressure of seven atmospheres, the bottoms are connected with the inner walls by the rods D and the jacket by stays. The steam-pipes (7, which serve for uniformly heating the fat, con- tribute also to the strengthening of. the digester. Underneath the digester, which rests upon supports, is a fire- place from which the gases of combustion, after passing through the flues G in the brickwork over as large a surface of the digester as possible, escape into the chimney. The digester is filled through the manhole E, and the membranous residue re- moved through the opening F. The pipe M, turning in the swivel-joint N, and provided on the end with a strainer to prevent the escape of foreign substances, FATS, FAT OILS, ETC. 115 serves for the removal of the liquid fat. With the pipe M com- municates the discharge-pipe U, by which the liquid fat can be conveyed to any desired place by ( the pressure prevailing in the digester A. The gases and vapors developed in rendering escape through the pipe J into an Argand furnace, so called by the inventors. Flcr. 18. Steam -Rendering Apparatus. The gases pass here first through the heated pipe system 0, and enter from below four burners, P, symmetrically arranged in a circle, where they are mixed with atmospheric air, ignited, and burned. The gases of combustion, in ascending, pass around the spirals and escape through the chimney T. The air required for combustion enters at Q, in the upper part of the furnace, an air-chamber in the brickwork, where it is heated and passes from below into the burners. To promote the draught in the digester, the small pipe 8 con- ducts heated gas into the space below the grate R. 116 MANUFACTURE OF SOAP AND CANDLES. The operation of rendering is conducted as follows : — After filling the jacket B with water to the highest point of the fines, and heating the boiler, the digester A is charged with the fat to be rendered, care being taken to place the strainer M at its highest point. The Argand furnace is heated at the same time by kindling a fire upon the grate R. As soon as the manometer indicates a moderate pressure, the cock on the discharge-pipe J is opened and the gases escape to the combustion furnace, where in the mean time sufficient heat must be developed to assure complete combustion of the noisome vapors. The heating of the apparatus is so regulated that the ten- sion of the steam in the jacket does not exceed four atmospheres and the pressure in the digester is not over 2.5 atmospheres. To recognize the moment of complete melting, samples are from time to time taken through the pipe U. For the manufacture of margarin, the selected tallow is freed from adhering particles of flesh and blood by first soaking in warm water and afterwards thoroughly washing in cold water. It is next introduced into a hashing machine, and when thor- oughly disintegrated melted by steam at 140° to 151° F. The melted fat is then allowed to stand until it deposits the floating fragments of membrane, which collect on the bottom, forming " scrap.' 7 The fat is then crystallized at 95° F. and subjected to pressure at this temperature. The residue is " prime press tal- low/' and is used in the manufacture of candles. The fat pressed out, known as oleomargarin, is used in the manufacture of artificial butter. By subjecting tallow to pressure at a low temperature, tallow oil is obtained, which remains liquid at an ordinary temperature. Commercial tallow frequently has a dirty gray color. Such tallow, to be worked into stearin by saponification, needs refining, as otherwise candles manufactured from it will not show the white appearance so highly valued. The refining consists in remelting the tallow with water, generally with an addition of common salt, alum, or soda. A very simple method to bleach tallow is to melt it and then stir in 6 to 10 pounds of soda lye of 20° to 24° B. for each 100 FATS, FAT OILS, ETC. 117 pounds of tallow and allow it to stand and settle. The brown sediment can be used for rosin grain-soaps. In a pure state the tallows are nearly inodorous ; on exposure to the air for some time, mutton tallow, however, acquires a pecu- liar odor, which, according to Chevreul, is due to the evolution of a volatile fatty acid which he terms hircic acid, the existence of which is, however, doubtful. Tallow consists of stearin, pal- mitin, and olein, their proportions varying in the fat from the different parts of the animal. There is no great difference in the saponification equivalents of the various varieties of tallow, which is readily explained by the fact that oleic acid and stearic acid fix nearly the same quantities of alkali, 1 gramme of oleic acid requiring 198.7 milligrammes of caustic alkali for saponification, 1 gramme of palmitic acid 218.9 milligrammes, and 1 gramme of stearic acid 197.3 milli- grammes. The iodine degree of tallow is 40, according to Hiibl, and that of the fatty acids separated from tallow, 25.9 to 32.8, according to Demski and Morawski. Tallow, as found in commerce, is frequently contaminated with water, dirt, particles of skin, etc. Such contaminations are readily detected by the method given on page 102. It is further adulte- rated with cheaper fats, such as bone fat, kitchen fat, residue from the manufacture of margarin, etc. Such adulterations cannot always be detected with certainty. The best guide is the deter- mination of the melting points, or, still better, that of the fatty acids separated from the tallow, which, according to Dalican, should never be below 111° F. Tallow adulterated with distilled wool fat has recently made its appearance in commerce. This adulteration can, however, be readily detected by the considerable percentage of cholesterin in the wool fat. Saponify the suspected tallow with caustic potash and shake the resulting soap with ether. The latter absorbs the cholesterin and leaves it behind on evaporation. By adding hydrochloric acid and chloride of iron to the residue a violet coloration is produced. Adulteration with cotton-seed stearin is detected by melting: the fat, crystallizing it in a drying box at 95° F., after eighteen 118 ■ MANUFACTURE OF SOAP AND CANDLES. hours pressing it through a cloth and determining from the nitrate the iodine degree, which, with filtrate from tallow con- taining cotton-seed oil, is from 75 to 80, and with that from pure tallow about 55. Before the introduction of palm-oil, cocoanut-oil and palm- kernel oil, tallow was the most important raw material used in the manufacture of soap. It saponifies only with weak lyes, requiring, according to its age, in the commencement of the operation a lye of 8° to 10° B. ; with this it readily forms an emulsion, which, on reaching the boiling point, is converted into a chemical combination. By continuing the boiling with this lye a viscid, thick soap-paste is obtained, which is not the case with any other fat. Generally the boiling is, however, continued with lye of 12° to 15° B., until the combination forms a clear, viscid paste, the exact fitting of which is recognized by the quick appear- ance of a gray edge on a sample upon the spatula. After the introduction of the combination with lye, most fats take up the further lye required very rapidly and well ; with tallow this process, however, takes places very gradually, and it is, therefore, necessary to add the lye in portions. By adding the portions of lye in rapid succession, it may happen that the soap-paste, notwithstanding it shows sharpness, is turbid and not saturated. This defect is best remedied by the addition of some weak lye with a moderate fire ; the paste gradually clarifies until all sharpness disappears, and only when this is the case will it be possible to determine how much lye is required for complete saponification. It may further occur that by adding too concen- trated lye (of about 20° B. or more) the combination formed may be entirely destroyed so that lye runs off. This fault is remedied with weak lye or water and boiling slowly. In very difficult cases it is best to interrupt boiling and squirt water over the soap-paste. Saponification is more readily and better effected by direct steam than by an open fire, since a large quantity of tallow can in a short time be converted into a clear paste free from scum, which, when properly " salted out," also yields a finished grain free from scum, so that for most purposes clear boiling is not required. 100 pounds of tallow saponified with soda lye yield at the FATS, FAT OILS, ETC. 119 utmost 165 pounds of ground grain-soap, which, however, dries out strongly, so that the bars warp tray-shaped. However, by boiling down solid, as is especially required in boiling over an open fire, 100 pounds give only 150 pounds of soap. By allow- ing the latter to cool in large frames it shows formation of grain. Lard. — In the United States hog's lard is largely used in the manufacture of soap and candles. It is rendered or melted in a similar manner as tallow ; chiefly over an open fire, though in large operations steam is found to present the most economical method. Lard has a granular, salve-like consistency, a pure white color, and agreeable taste ; on exposure to air it soon turns yellow and rancid. It consists of 62 parts of olein and 38 parts of solid fat (mostly palmitin), and contains, according to Allen and Thompson, 0.25 per cent, of non-saponifiable substance. By saponification 100 parts of lard yield, according to Braconnot, 8.8 parts of glycerin and 95 parts of fatty acids, which commence to congeal at 131° F., and become entirely solid at 125.5° F., but according to Mayer their melting point is at 95° F., and their congealing point at 93° F. The statements about the melting point of lard vary from 79° F. to 107.5° F. These variations may be largely due to the varying solidity of the fat from dif- ferent parts of the body and to different methods employed in the determination. The specific gravity of lard is 0.938 at 50° F. Its saponification equivalent is, according to Valenta, 195.3 to 196.6, and its iodine degree, according to Hiibl, 57.6 to 60. By subjecting lard to strong pressure at 32° F., it is separated into 62 parts of a colorless oil, the so-called "lard-oil," and 38 parts of a solid mass, consisting of tallow (margarin), palmitin, and stearin. Lard-oil has a pale color and mild. taste. It is used in the fabrication of soaps and pomades, as a lubricant, and in the wool industry. It has a specific gravity of 0.915 at 50° F., and begins to separate stearin at below 32° F. Its saponification equivalent is, according to Moore, 191 to 196. The solid portion is brought into commerce under the name of "solar stearin," and furnishes an excellent material for the manufacture of candles. Lard is frequently adulterated, the principal sophistication being with water ; alum or lime is sometimes added to enable it to absorb large quantities of water. An addition of 1 per cent. 120 MANUFACTURE OF SOAP AND CANDLES. of slaked lime or of 2 to 3 per cent, of alum will cover 10 to 12 per cent, of water. By melting and recongealing the lard, the foreign substances form a deposit on the bottom and can be read- ily determined. Some tallow is generally added to give the lard a firmer appearance. The behavior of lard towards lye is similar to that of tallow ; the older and more rancid it is the quicker saponification is ac- complished, while the fresh neutral fat requires in the commence- ment a weak lye. Lard is much liked for the preparation of smooth w r hite grain-soaps. Though lard by itself gives a very white soap, even if by bad treatment it has acquired a yellowish or dirty gray color, it is, on account of the lardaceous and some- what soft consistency of the soap, better adapted for working in connection with palm-kernel oil and cocoanut-oil, which give lean and brittle soaps, an addition of one-third or two-fifths of lard being sufficient in order to obtain a beautiful, solid, and deli- cate soap. Good lard is at present used only for toilet soaps. The lard from animals that have died by sickness has gene- rally a dark color and bad odor. In connection with palm-kernel oil it yields good results ; the best proportions are 2 parts of lard to 3 of palm-kernel oil or 3 parts of lard to 5 of oil. A larger quantity of lard might yield a soft or mottled product. The yield of pure ground grain-soap will generally reach about 155 per cent., though the softer a fat the lower the yield of pure grain-soap. Horse fat. — Generally speaking, the horse is poor in fat. The careless manner in which it is prepared from the carcass renders it rather repulsive, yet, when extracted from the recently slaugh- tered animal, it constitutes a very suitable and good material for the manufacture of soap. Horse fat varies in consistency accord- ing to the organs from which it is taken and the care given to its production. It is either solid, forming a real tallow r , or is more or less of the consistency of lard. The fat found in commerce has generally a more or less dark color, a bad odor, and the con- sistency of lard. As a rule it is not pure horse fat, but contains lard, bone fat, etc. By treating with strong lye in a similar manner as described for lard, it can be bleached, and forms then a very good material for white soaps, while the dark sediment FATS, FAT OILS, ETC. 121 can be utilized for dark soaps. Most of the fat being quite ran- cid, combination is effected with a medium lye, complete saponi- fication taking place with ease and rapidity. The application of this fat for household soaps is about the same as that of lard. Its peculiar sweetish odor makes it a suitable addition to palm- kernel oil to weaken the strong odor of the soap prepared from the latter. Bone fat. — The bones of all animals contain up to 3 per cent, of fat. Though it has not been thoroughly studied, the constitu- tion of bone fat seems to be about the same as that of other ani- mal fats, it being only richer in the glyceride of oleic acid, and, therefore, softer and easier to melt. To produce the fat the bones are broken as much as possible in a lengthwise direction. They are then brought into a kettle partly filled with water and heated to the boiling point, which causes the fat to float on the surface, where it is skimmed off with a flat iron spoon and passed through a sieve, which retains the solid particles. When it is noticed that no more fat separates, the bones are taken out by means of a large perforated shovel and replaced by fresh ones, so that the water may be used several times. Most bone fat is now obtained as a by-product in the manu- facture of animal charcoal or bone meal. The bones, before their mechanical comminution, are either steamed in closed iron cylin- ders for a few hours at a pressure of 2 to 4 atmospheres, or ex- tracted in a special apparatus with benzene. By the latter method the bones are more completely exhausted than by steaming, but the extracted fat has a strong odor of benzene which is difficult to remove. It is purified by remelting upon salt water and intro- ducing steam for some time. The fat obtained by boiling fresh bones has a white to yellow- ish color, a slight odor and taste, and is of a smeary consistency. It consists of stearin, palmitin, and olein. When thoroughly purified it keeps well and makes a good lubricant. The bone fat obtained as a by-product in the manufacture of bone meal is largely obtained from old, partly putrefied bones, and is of a dark color and unpleasant odor. It always contains a considerable quantity of free fatty acids and frequently calcium lactate and 122 MANUFACTURE OF SOAP AND CANDLES. calcium sebate, the latter permitting the incorporation of consid- erable water. The melting point of commercial bone fat varies from 68° to 83° F. The fatty acids of the fat from fresh bones melt, accord- ing to Hiibl, at 86° F. and congeal at 82.5° F. Valenta deter- mined the saponification equivalent at 190.9, and Demski and Morawski the iodine degree of the separated fatty acids at 55.7 to 57.3. In examining bone fat, attention must be especially directed towards dirt and water. The ordinary bone fat of commerce is difficult to bleach ; the frequently recommended methods with potassium bichromate and sulphuric acid or hydrochloric acid accomplishing the object in but few cases. The commercial bone fats contain a large quantity of free fatty acids, and, therefore, combine readily with strong lyes containing a considerable percentage of alkaline carbonates. In other re- spects their constitution varies, however, very much. There are, for instance, bone fats which in color and consistency resemble a poor quality of tallow and furnish a very good material for the manufacture of soap, while others resemble poor distilled oleic acid, and are incapable of forming cohering grain-flakes when boiled by themselves. Even with the better qualities of bone fat, the sub-lye is generally more or less turbid, and, on cooling, forms a gluey skin in consequence of the impurities contained in the fat. The yield varies very much. Good, solid bone fat may yield as much as 150 to 155 per cent, of good ground grain-soap, which is quite solid and lardaceous, though not so white as tallow grain-soap. Bone fat by itself is but little employed in the fabrication of soap, but much in connection with other fats. It is chiefly used for resin grain soaps, it being less adapted for smooth white grain soaps, as even the best bone fat does not give the pure white pro- duct so desirable for this variety. It can also be used in connec- tion with other fats for soft soaps, the lighter varieties being well adapted for grained soaps, however, only when the appearance of the product is of secondary importance, as is the case with soaps for the textile industry. For oil soaps only a small quantity can be worked in summer in connection with linseed-oil. FATS, FAT OILS, ETC. 123 Wool fat. — The wool of sheep contains a considerable quantity of a fatty body consisting chiefly of cholesterin, isocholesterin, cholesteryl stearate and palmitate, and other compound ethers of cholesterin, and can, therefore, be but incompletely saponified. Moreover, the so-called wool sweat (suint) contains a considerable quantity of potash soaps. The fat extracted from the crude wool by means of ether or bisulphide of carbon has a yellowish color and the peculiar odor of wool. For the manufacture of soap wool fat is of but little value ; it cannot be worked by itself, and is chiefly used for resin soaps. Some years ago a method for purifying wool fat and mixing the purified article with water was patented. It forms a white salve-like mass, to which the term " lanolin" has been applied, and is used as a vehicle for salves and pomades. Wool fat can be distilled with superheated steam, and then forms a white or yellowish mass, which melts at about 107.5° F., and recongeals at 104° F. It is frequently used as an adulterant of tallow (see tallow). Glue fat. — In making glue from hides, tendons, etc., much fat is collected, which, if well prepared, can be usefully employed in making soap. The commercial article contains considerable lime and other impurities, which can, however, be removed with dilute sulphuric acid. When the fat is boiled in a five per cent, solu- tion of sulphuric acid for about one hour, the lime and other impurities are carried down with the water, the clear grease float- ing on the surface, whence it is ladled off. This fatty acid will make with soda lye, with or without resin, a good and firm soap, useful for all domestic purposes. It should be boiled, for in the cold soaps it would not answer so well. Neafs-foot oil. — This fat is obtained from the bones of the legs and feet of cattle and sheep. If this product were abundant, it could be usefully applied in making soaps of good quality, but it is generally used as a lubricant and for dressing leather for which it is admirably adapted. It is of a greenish-yellow color, and Avhen fresh has no odor, is limpid at ordinary temperatures, be- coming solid in the cold. Its specific gravity is 0.915 to 0.91(3 at 59° F. It forms with soda lye a very fine white soap, partak- 124 MANUFACTURE OF SOAP AND CANDLES. ing of the nature of the fat, being somewhat soft, oleic acid being the largest constituent of the oil. Fish-oils and train-oils. — In this category are classed the oils derived from various marine animals, which in commerce are generally designated by the names of their sources, as whale, seal, cod-liver oil, etc. They are fluid at an ordinary temperature, and have a peculiar disagreeable odor and taste, due to the admixture of volatile fatty acids. In these oils, the oleic acid occurring in other oils, is partly replaced by physetoleic acid. The oils derived from several marine mammalia contain combinations which are not glycerides, but ethers of the higher fatty alcohols. All train-oils are sparingly soluble in cold alcohol, somewhat more freely in hot alcohol, and very readily in ether. Most of them are blackened by gaseous chlorine. Train-oils are chiefly adulterated by compounding a good quality with a poorer one. Such sophistication can scarcely be detected, as it is difficult to distinguish the separate oils, their specific gravity varying but little, being between 0.915 and 0.930. Neither do the melting points of the separated fatty acids, the saponification equivalents and iodine degrees furnish a sufficient guide for the examination of train-oils. An admixture of foreign fats is recognized by mixing 1 part of train-oil with 2 parts of concentrated sulphuric acid in a tall beaker glass. If the train-oil is free from foreign fat, a clear mixture is obtained. Various means are applied in purifying the bad smelling and dark-colored train-oils. Shaking with milk of lime, with diluted potash or soda lye, common salt, and copperas, is a common device, as well as filtering with wood ashes. According to Davidson, train-oil should be shaken with a decoction made of oak bark, then have mixed with it 4 parts of chloride of lime (bleaching powder) stirred into 12 parts of water, permitting it to clear off, when a thick whitish mass will be separated, to which is added dilute sulphuric acid to settle the lime which becomes free. This is an excellent means for disinfecting train-oil, since by this treatment it loses the greater part of its disagreeable smell, so that such train-oil before saponification appears almost odorless. But, nevertheless, the smell reappears when the oil is FATS, FAT OILS, ETC. 125 converted into soap. Hence train-oil can only be used in manu- facturing very common soaps, or by mixing small quantities of it with other fats. The head cavity of the sperm whale, called by the whalers the case, contains an oily fluid, which, after death, concretes into a granulated substance of a yellowish color, called spermaceti. It is separated from the fluid portion (spermaceti-oil) by filtering, pressing, boiling with some potash or soda lye, and rinsing in cold water. Spermaceti is used, especially in England, in the manufacture of fine candles, while the spermaceti-oil forms an excellent lubricant. Fats and Oils of Vegetable Origin. The vegetable fats and oils applied to the manufacture of soap are very numerous and valuable and are found in the fruits, seeds, etc., of plants. The most important solid fats are cocoanut-oil, palm-oil, and palm-kernel oil. There are various other solid fats found in tropical countries, such as shea butter, illipe-oil or bassia-oil, piney tallow, Chinese tallow, cocoa butter, dika-oil, butter of nutmeg, etc., which are very suitable for the manufac- ture of soap, but are little used on account of their high price, and will therefore be only briefly mentioned. Of the fluid vege- table fats are used : olive-oil, sesame-oil, peanut-oil, castor-oil, cotton-seed oil, linseed-oil, hemp-oil, niger-oil, cameline or Ger- man sesame-oil, and small quantities of colza-oil and poppy- seed oil. Cocoanut-oil. — This valuable oil is obtained bv boiling or pressing the ground or crushed kernels of the nuts of Cocos nnci- fira. the cocoanut palm, which is found in nearly all tropical countries. Most of the oil is imported from Ceylon and Cochin China, though recently the dried kernels, called " coprah," are exported to Europe, where the oil is extracted either by expres- sion or extraction. Coprah contains 60 to 70 per cent, of fat. Two varieties are known in commerce, sun-dried and kiln-dried coprah. Fresh cocoanut-oil has a beautiful white color, a mild taste, and a peculiar, though not disagreeable, odor. It becomes soon rancid 126 MANUFACTUKE OF SOAP AND CANDLES. and acquires a somewhat disagreeable, acrid taste and odor. Entirely fresh oil melts at 68° F. ; the commercial oil from Ceylon and Cochin China shows a melting point of about 75° F. ? and the Brazilian cocoanut-oil (from Eldis butyracea) melts at about 80.5° F. By subjecting the coprah to a moderate cold pressure an oil is obtained which melts below 68° F. and con- geals at 53.5° to 55.5° F., becoming heated thereby to 59° F. Cocoanut-oil contains chiefly the glycerides of laurostearic, niyristic, palmitic, and caprylic acids, and small quantities of capronic and capric acids. St. Evre and Bromeis claimed to have found special fatty acids, which they termed cocinic acid ; but Heintz has shown that St. Evre's cocinic acid is a mixture of laurostearic acid with capric acid, and Bromeis's cocinic acid a mixture of laurostearic acid with myristic acid. Cocoanut-oil has the highest saponification equivalent of all the fats hitherto examined, by which it can be readily distinguished from all other fats, with the exception of palm-kernel oil, which comes next in this respect. Valenta examined several cocoanut- oils and found their saponification equivalent to be from 257.3 to 268.4. The iodine degree of cocoanut-oil is, according to Hiibl, 8.9, and that of the separated fatty acids, according to Demski and Morawski, 8.39 to 8.79. The separated fatty acids melt at 76° to 77° F. and congeal at 66° to 69° F. On account of its large percentage of laurostearin, the action of cocoanut-oil in the process of saponification is quite different from that of tallow and most other fats. It requires strong caustic lyes and forms soaps which can only be separated by concentrated solutions of common salt, and then become so extraordinarily hard that they cannot be cut. For this reason a clear boiling to the solid would in case of cocoanut-oil soap be entirely contrary to the end in view and very difficult. While, furthermore, tallow, for instance, treated with very strong lye, floats on top and then can scarcely or not at all be saponified, in the case of cocoanut- oil just the contrary happens. It does not form that milk-like mixture (emulsion) with weak lyes by which the process of sapon- ification is usually preceded, but floats as a clear fat above ; only when, by continued boiling and evaporation, the lye has reached a certain strength, the saponification suddenly ensues. For sapon- FATS, FAT OILS, ETC. 127 ifying cocoanut-oil lyes of such strength are used that the soap, with the lye, receives the intended contents of water, and a separa- tion becomes, therefore, unnecessary. Of course, the amount of the alkali must be so accurately calculated that the soap receives no excess of alkali, or at least but very little. Cocoanut-oil can also be saponified in the so-called cold way, i. e., can be converted into soap by stirring in strong caustic lyes at a temperature little above the melting point of the oil. Soaps from cocoanut-oil have the property of absorbing a great deal of water without suffering in firmness and appearance. They dis- solve freely in water, yielding a strong lather, which is, however, not so durable as that from tallow soap. Soaps from pure cocoa- nut-oil have the disagreeable property, even if they do not con- tain an excess of alkali, of producing a burning sensation and redness upon a sensitive skin, and being strongly inclined towards rancidity, whereby they acquire a bad odor and unsightly appear- ance. Three principal kinds of cocoanut-oil are at present known in commerce — Cochin China-oil, Ceylon-oil, and coprah-oil — the first being much the best and purest in color. It is best adapted for cold saponification, but is only good when not too old. When old oil of a certain degree of rancidity is stirred together with strong lye, the mass becomes thick too quickly and the soap shows formation of granulation. Commercial Ceylon-oil is gen- erally quite rancid, and, therefore, not well adapted for cold saponification, and besides, the soaps prepared from it are not pure white, but of a grayish shade. Coprah-oil is not very rancid, and, therefore, suitable for cold saponification ; it does not yield, however, pure white soaps, and hence is not adapted for the fabrication of toilet-soaps. This defect can, however, be rem- edied by the following method of refining : Boil 750 pounds of coprah-oil with 15 pounds of soda lye of 6° B. and 10 pounds of water for half an hour, constantly removing the scum. Then add 1J pounds of common salt, remove the scum, and let the whole boil half an hour longer. Repeat the boiling with 1J pounds more of common salt and let the oil stand over night for the salt water to settle. 128 MANUFACTURE OF SOAP AND CANDLES. Palm-oil. — Vast quantities of this oil are consumed in the fabrication of soap, especially in England, where it was first used. It is obtained by boiling or pressing the fruits of various species of palms, chiefly of Avoira Elaeis or Elaeis guianensis and Elaeis melctnococca. The principal places of production are Western Africa (Guinea) and South America (Guiana), while some of it is brought into commerce from the Canaries, Madeira, and other places. The largest quantity and best quality of palm-oil come from the West African coast south of Sinoe, in the Republic of Liberia, to Cameroon, in the Bay of Benin. The fruits of Avoira Elaeis are dark orange-yellow, almost brown, of the size of a pigeon's egg, and contain a solid kernel under a fleshy cover. The latter yields the product known as palm-oil, which is directly brought into commerce from the localities where the palms grow. The kernels also yield an excellent oil, known as palm-kernel oil, the manufacture of which is, however, principally carried on in Europe, where it is either expressed or extracted by means of carbon bisulphide or benzene. Palm-oil is of an orange-yellow to red-brown color, of a buty- raceous consistency, and, when not rancid, has the odor of orris- root. The melting point of fresh palm-oil is at about 80.5° F., while that of rancid oil is much higher, rising to 108.5° F. The melting point of the fatty acids separated from palm-oil varies between 116.5° and 118.5° F., and their congealing point be- tween 104° and 113° F. The saponification equivalent of palm- oil is, according to Valenta, 202 to 202.5, and that of the sepa- rated fatty acids 206.5 to 207.3. The iodine degree is, according to Htibl, 51.5. Palm-oil consists chiefly of palmitin and olein. A very char- acteristic feature of this fat is the great quantity of free fatty acids it contains. In fresh palm-oil has been found one-third and in an old sample as much as four-fifths of its weight of free fatty acids. The greater portion of glycerin separates as such and can be obtained by extraction with water. The reddish-yellow color of palm-oil is not destroyed by sapon- ification, so that the soap manufactured from the crude product shows a yellow color. In the manufacture of stearin the coloring FATS, FAT OILS, ETC. 129 substance can be destroyed by acid saponification and distillation, but not by ordinary lime saponification. If white soaps are to be manufactured, the palm-oil must first be bleached. This is done either by heating to a certain degree, by heat and air, or by chemical agents. The application of heat, i. e., heating the oil to from 428° to 464° F., is the simplest method of bleaching. Impure oil must, however, first be purified by melting upon water at a moderate heat. The supernatant clear fluid is then drawn off from the sediment, brought into an iron kettle, and quickly heated to 396° F., which suffices for most varieties of palm-oil, though some re- quire a higher temperature. For the removal of the noxious vapors the kettle is covered with a well-fitting lid, in which an iron pipe is inserted, which opens into the chimney of the fire- place. Klepzig,* who is very much in favor of bleaching by the ap- plication of heat, quickly brings the temperature to 392° F., and then heats carefully to from 419° to 428° F., keeping up the latter temperature for one hour without stirring. In about half an hour the oil has acquired a lemon color and is perfectly clear, the yellow coloration disappearing, as a rule, entirely in 1 \ hours, and the oil becoming dirty gray. By pouring a few drops of the oil upon a plate, fine particles of carbon will be observed floating in them. The fire is then withdrawn and the oil allowed to stand quietly in the kettle. With some experience it can be readily judged whether the oil is to be kept for some time longer at the indicated temperature or heated to a still higher degree. Oil purified before heating shows, when cold, a whitish color shading into brown ; oil not previously purified is dirty gray from the many finely-divided particles of carbon suspended in it. These impurities, however, do not injure the oil for the manu- facture of soap, as they are salted out. Klepzig was of the opin- ion that bleaching was effected by this finely-divided carbon ; this, however, is not correct, since well-purified oils, in which the formation of carbon is very slight, are also bleached by the ap- plication of heat. This method of bleaching simply depends * Die Palmolbleiche durch Kohlenstoff. Leipzig, 1857. 9 130 MANUFACTURE OF SOAP AND CANDLES. upon the fact that the coloring substance of palm-oil is destroyed by heat. It has the defect that the bottoms of the kettles suffer much. With careful work and good, pure palm-oil the loss in weight is 1 to 1J per cent. To bleach palm-oil by the agency of heat and air, it is heated to 212° F., and at this temperature brought in contact with the air which is accomplished by various mechanical appliances. The most simple is to fill a fine-roeshed sieve fastened to a long handle with oil 7 raise it up quickly, and bring the oil in contact with the atmospheric air by allowing it to run back into the kettle. By frequently repeating this rather slow process the oil is bleached, though as a rule incompletely. A better arrangement is a sort of paddle wheel so adjusted that one-half of it dips into the oil. By setting the wheel in motion the paddles lift up a portion of the oil, allowing it to run back in a fine stream into the kettle. Though this mode of bleaching has the advantage of not injuring the agreeable odor of the oil it is now seldom practised. Bleaching by chemical agents is effected by oxidizing substances, the best being chromic acid, i. e., a mixture of potassium bichro- mate and hydrochloric acid. The process as executed in most soap factories is as follows : The palm-oil is first purified by melting upon water. After allowing the impurities to settle the supernatant clear oil is drawn off and allowed to cool to 122° F. To 1000 pounds of oil are then added with constant stirring 50 pounds of hydrochloric acid and 12 pounds of potassium bichro- mate previously dissolved in 24 pounds of boiling water. After stirring ten to fifteen minutes the oil shows a dark, dirty gray color. Sometimes a few pounds of sulphuric acid are added. The stirring is continued until the oil is entirely clear with a bluish lustre. 60 to 80 pounds of hot water are then poured over the oil by means of a watering-pot, and after covering the vat it is allowed to stand till the next day. With most varieties a much smaller quantity of potassium bi- chromate suffices, 1000 pounds of oil frequently requiring only 5 to 6 pounds. In a soap factory which we had occasion to visit, where much palm-oil is bleached, the process is carried on according to the method recommended by Bolley. 1000 pounds of melted palm-oil are brought at 122° F. into a wooden vat; 5 pounds of FATS, FAT OILS, ETC. 131 potassium bichromate are then added, and, after thorough stirring, 10 pounds of hydrochloric acid, and finally J pound of sulphuric acid. Stirring is then continued half an hour and a sample taken. If the oil proves still yellow, some more potassium bi- chromate, hydrochloric acid, and sulphuric acid are added until the desired result is obtained. The oil is then brought into a copper kettle and boiled for some time with water to remove all constituents of the bleaching agent. It is then allowed to stand covered for some time, and finally the supernatant clear fat drawn off. Palm-oil bleached by means of potassium bichromate has fre- quently a greenish shade, which is due to a small quantity of chromic oxide contained in it. This can be extracted, and a faultlessly white product obtained by boiling with dilute hydro- chloric acid and remelting the oil upon pure water. Commercial palm-oil varies very much in quality, the prima lagos and secunda logos being the best, the former being more readily bleached than the latter. Next in quality is the old (Mahar-oil, which is also readily bleached, especially by chemical means. The oils from Accra and Benin are not so pure as the preceding ones, and very unequal in their behavior during bleach- ing. They are generally used for dark grain-soaps and rosin grain-soaps. The crude oils from Cameroon, Gaboon, and Liberia are generally remelted on board the vessels and brought into commerce under the name of purified. Cameroons. They are generally very rancid, and, notwithstanding their name, by no means free from dirt. They cannot be as readily bleached as lagos and old Calabar-oil, and generally require chemical agents for the purpose. How much commercial palm-oils vary is shown by the follow- ing table published by H. Yssel de Schepper and A. Geitel,* which gives the percentage of water, dirt, and neutral fat of a large number of palm-oils, and the congealing points of the fatty acids obtained from them : — * Dingler's Polytechn. Jour., 245, 295. 132 MANUFACTURE OF SOAP AND CANDLES. Name. Congo . Saltpont . Add ah . . Appam Winnehab Fernando-Po Brass . . New Calabar Niger . Accra . Benin . Bonny Great Brassa Cameroons Cape Labon . Cape Palmas . Half Jack Jack Lagos . Loan do Old Calabar . Cold Coast Sherbo Gaboon Water. Per cent. 0.78-0.95 3.5-12.5 4.21 3.60 6.73 2.68 3.05 3.82 3.0 2.2-5.3 2.03 3.0-6.5 2.4-13.1 1.8-2.5 3.6-6.5 9.7 1.9-4.2 0.5-1.3 1.5-3.0 1.3-1.6 1.98 2.6-7.0 2.0-2.8 Dirt. Per cent. 0.35-0.7 0.9-1.7 0.35 0.596 1.375 0.85 2.00 0.86 0.70 0.60 0.20 1.2-3.1 0.6-3.0 0.2-0.7 0.7-1.5 2.70 0.7-1.24 0.3-0.6 1.0-1.9 0.3-0.8 0.50 0.3-1.2 0.3-0.7 Neutral fat. Per cent. 16-23 15-25 18 25 20 28 35.5 40 40-47 53-76 59-74 44-88.5 41-70 67-83 55-69 67 55-77 58-68 68-76 76-83 69 60-74 70-93 Cougealing point of the fatty acid. Degree F. 114.50 79 111.3 114 114 114.5 113 113 113 111.2 113 112 112 112 105.8 107.7 102.2-106.3 113 112 112 105.8 107.6 112 To obtain the oil from the sediment formed by storing large quantities of palm-oil, the sediment is boiled upon water, and after standing for some time the supernatant clear oil drawn off. The slimy residue is brought into large barrels, and after adding, with constant stirring, some sulphuric acid, and continuing the stirring for some time, the barrels are covered and the contents allowed to settle. After a few hours the dark-colored oil, which has separated, is drawn off, and can be either bleached with potassium bichromate and acid or immediately used for dark soaps. The sediment obtained by bleaching with chemical agents also contains much oil, and is, therefore, washed with hot water with an addition of sulphuric acid. The oil obtained, though dark, yields quite pale soaps, which in odor and firmness are not infe- rior to other palm soaps. Palm-oil was formerly much adulterated, and substitutes for it consisting of mixtures of wax, tallow, and lard colored with turmeric and scented with orris root, were even found in com- merce. Such adulterations and mixtures could be readily detected FATS, FAT OILS, ETC. 133 by the test with glacial acetic acid, which dissolves palm-oil, but leaves all the rest undissolved. The addition of turmeric is recognized by the brown color formed on stirring in soda lye. With the present prices of palm-oil such adulterations need, however, not be feared, as they would not pay. All palm-oils, no matter how much they may vary in quality, yield a firm soap of an agreeable odor, the scent remaining quite perceptible in combination with other fats and oils and even with resin. Palm-oil, crude or bleached, is readily saponified. It yields, even with weak lye of 8° B., a quite thick and viscid soap paste. Generally it is, however, saponified with lye of 12° to 15° B., yielding, when thoroughly salted out, an abundant grain quite free from scum, which, if the paste was entirely clear, is thor- oughly saturated. Since palm-oil is generally quite rancid, and contains, therefore, free fatty acids, a lye of 15° B., which, with a high percentage of lime, always contains some alkaline carbon- ate, is completely exhausted, especially when adding it carefully towards the end of the operation and boiling slowly. Saponifica- tion with direct steam is especially quick and perfect, the grain separating almost entirely clear, the best proof of a complete saponification. On account of the large content of palmitic acid, palm-oil yields a good firm soap, notwithstanding the large percentage of water retained even by grain-soap. Palm-soap, when made from pure oil with soda lye, will become with age too hard to lather well. This defect can be overcome in two ways, either by using about 2 per cent, of potash lye with the soda lye, or by adding about that quantity of resin to the oil used, the latter making a soap that from its solubility and free lathering is quite popular with most people. In a variety of toilet-soaps palm-oil enters to great advantage, for if the oil be properly refined and bleached the odor is exceed- ingly pleasant and combines very well with nearly all the volatile oils commonly used in soaps ; besides, the soap will require a less quantity of the expensive oils or perfuming substances. One hundred pounds of pure oil yield 162 to 165 pounds of fresh ground soap. 134 MANUFACTURE OF SOAP AND CANDLES. The principal use of palm-oil, besides the fabrication of soap, is in the manufacture of stearin. Palm-kernel oil. — The kernels of the palm fruit were formerly thrown away, but, as previously mentioned, are now brought to Europe, where the oil is obtained either by expression or ex- traction with carbon bisulphide or benzene. The oil obtained by expression is yellower than that by extraction. The kernels reach the market freed from the woody shell. The percentage of oil varies between 85 and 50 per cent., though some kernels, it is claimed, contain as much as 60 per cent, and more. As the oil obtained by expression contains vegetable albumen and mucus, it must be allowed to rest for a long time in a melted state for purification and clarification. Purification by sulphuric Fie. 19. ooooooooooooooooooo oooooo oooooooooooooo oooooooooo ooooooooooooooooooooooooo oooooooo ooooo ooooooooooo ooooooooooooooooooooooooo oooooooooooooooooooooooo oooooooooooo cooc ooooooooo oooooooooooooooooooooooo ooooooooooooooooooo oo o o o c ooooo ooooo oo oo oooooooooo oooooooooo OOOOOOOO OOOOOO OOOOOOOOOOO ooooooooooooo ooooooooo oo oooooooooooooo oooooooo oo oooooooooooooo A, decanting boxes; B, filtering: boxes; (7, sieve- box; D, slit in A; E, jacket around A ; F, discharge-valves ; G t valve-rods ; H, discharge-cock ; J, supports ; K, feed-pipe. FATS, FAT OILS, ETC. 135 Fig. 20. acid being tedious, Schneider's apparatus, shown in Figs. 19 and 20, is well adapted for the purpose. The apparatus is very compact, but can be easily taken apart and cleansed. It contains three series of boxes made of wood and sheet-iron, viz., the decanting boxes A and the filtering boxes B, which sit in the sieve-box C. All the boxes are open on the top. The boxes A consist each of a bottom and four vertical sides, each provided with a vertical slit D near the upper edge. The jacket E surrounds the boxes and joins their sides above the slit D. The filtering boxes B consist of bottoms and frame- work sides, the latter being covered with linen or some other fil- tering material. The lower halves of the sides of the sieve-box Care perforated. The filtering boxes B and the sieve-box C are provided with valves F, which are set by the valve-rod G; the sieve-box is further provided with a discharge-cock H. 136 MANUFACTURE OF SOAP AND CANDLES. The apparatus works in the following manner : The sieve-box C is suspended over the reservoir which is to receive the clarified oil, and the decanting boxes A and filtering boxes B are placed upon the supports J in the sieve-box C The oil to be clarified is introduced through the pipe K into the innermost decanting box A, passes through the slit I) into the second box A, and from here into the filtering box B, and after penetrating through the filtering material with which the sides are covered, arrives finally in the sieve-box C and leaves it through the perforations. The impurities are precipitated on the bottoms of the boxes and the filtering material, which, of course, must be occasionally cleansed. This is effected by means of the valves F and the cock H. Palm-kernel oil consists chiefly of the glycerides of lauric, stearic, palmitic, and oleic acids, and contains only small quanti- ties of tricaprin, tricaprylin, and tricapronin (and perhaps some trimyristin) in about the following proportions : Triolein 26.6 per cent. ; tristearin, tripalmitin (trimyristin ?) 33 per cent. ; tri- laurin, tricaprin, tricaprylin, tricapronin 40.4 per cent. The melting-point of fresh palm-kernel oil is at from 77° to 79° F. ; that of old rancid oil being somewhat higher. Its sapon- ification equivalent is, according to Valenta, 247.6, and that of the separated fatty acids 265.8. By the determination of the saponification equivalent the fatty acids of palm-oil can be readily distinguished from those of palm -kernel oil. The iodine degree of palm-kernel oil is, according to Hiibl, 13.4 to 13.6, and that of the separated fatty acids, according to Demski and Morawski, 12.07. The behavior of palm-kernel oil, as regards saponification, re- sembles that of cocoanut-oil ; the behavior of both these fats, though not exactly alike, being, no doubt, due to the large per- centage of laurostearin characteristic of them. Palm-kernel oil requires strong caustic lyes, though of a less degree than cocoa- nut-oil. While palm-kernel oil combines quickest with an initial lye of 26° to 30° B., and the combination takes place with greater difficulty the more these degrees are exceeded, cocoanut-oil readily forms a combination with much stronger lye. In their behavior towards common salt the soaps from the two fats also resemble FATS, FAT OILS, ETC. 137 each other, but are not alike. The salting out of soaps from palm-kernel oil, though difficult, is effected with greater ease than that of soaps from cocoanut-oil. It has been frequently asked whether there is a difference be- tween expressed and extracted palm-kernel oil ; at the present time this question can be unreservedly answered with " No." Cases, formerly referred to by different writers, of soap from ex- tracted oil turning entirely black in boiling, with the develop- ment of an intense odor of carbon bisulphide, are scarcely pos- sible now, and were, no doubt, due to extracting the oil with impure carbon bisulphide and insufficient subsequent purification. The manner of detecting carbon bisulphide in extracted oil has been given on page 108. The oil can be freed from carbon bisulphide, or rather from its products of decomposition, by boiling it for some time with salt water by the introduction of steam. To test whether the desired result is attained, take from time to time a sample of the oil, filter it through paper until entirely clear and saponify it. The resulting soap must not show a bad odor. Shea butter, galam butter or bambuh butter is obtained by boil- ing with water the comminuted kernels of Bassii Parhii, a tree belonging to the Sapotece species, growing in the interior of Africa. The fat is of a butyraceous consistency, gray-white or greenish- white, of a peculiarly viscid and sticky nature (similar to a mix- ture of fat and turpentine), and a peculiar, aromatic odor. It keeps a long time without turning rancid. It melts at between 82.5° and 84° F., though statements of various observers vary very much in this respect. With soda lye it yields a very hard, white soap. Mahwa butter, llloopa oil or Bassia oil is obtained from the seeds of Bassia longifolia and Bassia latifolia. The fresh fat is yellow or greenish-yellow, and has an agreeable and mild taste and odor. On exposure to air and light, the coloration disappears quite rap- idly and the fat becomes rancid. It dissolves partly in alcohol and completely in ether, carbon bisulphide, benzol, etc. It is readily and completely saponified, yielding a hard, white soap of an agreeable odor, which is capable of fixing a considerable quantity of Avater without losing firmness. 138 MANUFACTURE OF SOAP AND CANDLES. According to Valenta, mahwa butter melts at 78° F. and con- geals at 63.5° to 65° F., while the fatty acids separated from it melt at 103° F. and recongeal at 100.5° F. The fat consists of palmitin and olein ; its saponification equivalent is 192.3. Piney tallow, also called vegetable tallow or vateria fat, is ob- tained from the seeds of Vateria indica, L., a tree indigenous to the East Indies. The air-dried seeds contain 49.21 per cent, of a solid, greenish-yellow fat, which soon becomes white on ex- posure to light, and has a peculiar slightly balsamic odor. The fat prepared from commercial seeds shows a melting-point of 107.5° F., while, according to other statements, it melts at 98° F. and congeals at 87° F. It saponifies with great ease, 1 gramme of fat requiring 191.9 milligrammes of caustic potash, whereby 8.4 per cent, of glycerin is separated. The fatty acids separated from the products of saponification melt at 134° F. and congeal at 130.5° F., and consist of a mixture of oleic acid and solid fatty acids. The latter amount to about 60 per cent, of the weight of the vegetable tallow and melt at 147° F. Not- withstanding this high melting-point, the pre-eminently crystal- line product is rather soft and readily friable. Chinese tallow is obtained from the seeds of Stillingia sebifera, or the tallow tree indigenous to China. The fruit of the tree is a black, somewhat globular capsule, and contains three egg- shaped seeds coated with a thick, hard, tallowy layer, while the seed-kernel contains a liquid fat. The tallow is obtained by one of two methods. The seeds freed from the capsules are treated with steam, whereby the tallow (about 20 to 30 per cent, of the weight of the seeds) melts off; the seeds are then com- minuted in order to obtain the liquid fat. Or the seeds are com- minuted at once, and the tallow and liquid fat boiled out together with water. The tallow obtained by the first method is white or greenish-white, inodorous, quite hard, and melts at 104° to 105° F. : it consists chiefly of palmitin. The fat obtained according to the other method forms a whitish or gray-white mass with a slight odor; it becomes yellow to brown by storing, shows a slightly acid reaction and congeals at about 95° F. Chinese tallow, it is claimed, has been for some time used in England in the manufacture of candles and soap. About its FATS, FAT OILS, ETC. 139 value for these purposes B. Lach* says: " To obtain a service- able product from this fat alone will very likely never succeed. Chinese tallow consists chiefly of tripalmitin, and, though it saponifies well under high pressure with lime, the resulting mass has an unsightly appearance and cannot be pressed. The press cloths become smeary and burst ; besides, the fatty acids, even if successfully obtained, are and remain gray in spite of thorough washing. Subjecting the fatty acids thus obtained to distillation does not produce much better results. The distillate, though of a better appearance, is soft, cannot be pressed, and is serviceable only as an addition to other material. " By combining Chinese tallow with other tallows quite dif- ferent results are, however, obtained ; it then acts almost like press-tallow. A mixture of an equal quantity of bone- fat and Chinese tallow yields a beautiful mass, which is readily pressed, and, when subjected to distillation, gives a distillate which also can be pressed. Worked by itself Chinese tallow yields ten per cent, of glycerin of 28° B., it being, however, advisable to re- peatedly wash it with dilute sulphuric acid previous to the opera- tion. The amount of dirt separated by this means is almost in- credible. " Commercial Chinese tallow varies very much in quality. The melting-point of the neutral fat, which is always much below that of the fatty acids, differs considerably, being some- times as low as 95° F. The fatty acids generally drain off at 131° F.; with pale yellow tallow the temperature, however, rises to nearly 140° F., and with green tallow sinks to 120° F. " Chinese tallow contains frequently considerable water, though in examining it, special attention should be directed towards dirt in the canisters, of which there is frequently found an astonishing quantity." Under the name of " vegetable tallow" another vegetable fat is brought into market which is obtained, chiefly in Borneo, from various species of Hopea, especially Hopea splendida and Hopea aspera. The ripe fruits are piled up in a moist place and allowed to germinate a little. They are then dried in the sun until they * Chem. Zeitung, 1885. S. 941. 140 MANUFACTURE OF SOAP AND CANDLES. are brittle, when they are deprived of their shell and put into a rattan or bamboo basket suspended over boiling water. The arising steam renders the fruits soft and plastic. The fat is then expressed by squeezing the doughy mass in a cloth, and is poured into joints of bamboo, by which it receives the cylindrical form in which it is met with in commerce. By the natives the tallow is used for culinary and lighting purposes. It is largely exported to England, where it has been successfully employed as a lubri- cating agent, being very valuable for this purpose, far surpassing even olive oil. In Manilla it is employed in the manufacture of candles. The tallow is white and hard and crumbling at an ordinary temperature, but softens at a moderate heat, and has a somewhat nutty taste and odor. According to Fielding, it remains hard up to a temperature of 64.5° F., softens between 80.5° and 104° F. to a pasty mass, and melts at 112° F. It dissolves in about half its weight of cold ether, is sparingly soluble in cold but freely in hot aceton ; on cooling the greater portion is, however, resepa- rated. It dissolves in half its weight of chloroform, is readily soluble in oil of turpentine, and very freely in carbon bisulphide, and in hot benzene. It is also soluble in about 30 parts of cold and 20 parts of hot alcohol. Cocoa butter is obtained as a by-product in chocolate factories by hot expression of the cocoa bean, the fruit of Theobroma cocoa, L. In a fresh and pure state the fat is yellowish, but becomes nearly white with increasing age. It smells like roasted cocoa beans and keeps a long time without becoming rancid, and for this reason is much employed for cosmetic and pharmaceuti- cal preparations. The specific gravity of fresh cocoa butter is 0.950 to 0.960, and that of old 0.947 to 0.950. The statements in regard to the melting-point vary between 77° and 91.5° F., the variations being, no doubt, chiefly due to the methods em- ployed. Melted cocoa butter can, according to Rudorff, be readily cooled to 71.5° F., and on congealing shows a permanent increase of temperature to 82° F. Cocoa butter gives a clear solution with ether, oil of turpentine, and chloroform. It consists, accord- ing to Traub, of the glycerides of oleic, palmitic, stearic, lauric, and arachidic acids, and is readily saponified. Its saponification FATS, FAT OILS, ETC. 141 equivalent is 198 to 203, and its iodine degree 51.0. The sepa- rated fatty acids melt at 125.5° F., and congeal at 123.5° F. Genuine cocoa butter is readily recognized by the taste, odor, and consistency. The principal adulterations are with wax, stearic acid, paraffin, and especially with beef kidney fat. All these substances are readily recognized by dissolving 1 part by weight of cocoa butter in 2 parts by weight of ether without the assistance of heat. Pure cocoa butter yields a clear solution, remaining so for at least one day ; in the presence of more than 10 per cent, of tallow or wax the solution is more or less turbid, or forms a whitish sediment. The presence of tallow can also be detected by the odor evolved by an ignited wick soaked in the melted fat. An addition of stearin is recognized by boiling the suspected sample with solution of sodium carbonate and filtering after cooling; if stearin be present, stearic acid is separated by adding diluted sulphuric acid to the filtered fluid. Cocoa butter adulterated with paraffin feels soapy to the touch and shows a specific gravity of below 0.9. The paraffin can be quantitatively determined by the saponification test. Dika-oil, or loild mango-oil, is obtained from the seeds of Man- gifera gabonensis, a tree indigenous to the west coast of Africa. When fresh it is pure white and of a mild cocoa-like odor and taste, but when stored for some time it becomes yellow and rancid. It melts at from 86° to 89.5° F., contains the glycerides of lauric and myristic acids, and is readily saponified. Expressed oil of nutmeg, butter of nutmeg, or oil of mace is ex- tracted by heating and pressing from the kernel of the nutmeg, the fruit of Myristiea fragrans. It is generally brought into commerce from the East Indies in oblong four-cornered pieces as thick as the arm and wrapped in plantain leaves. A large quan- tity of the fat is also prepared in Europe by pressure or extrac- tion with absolute alcohol. The latter (oleum nucistas germanicum) is the cheaper and purer article. Expressed oil of nutmegs is reddish-yellow or yellowish brown-red (generally whitish and reddish-marbled), of the consistency of tallow, but more brittle and crumbling. It is unctuous to the touch, lighter than water, and enveloped in paper and ignited burns almost without smoke and with a very slightly sooting flame, and, when extinguished, 142 MANUFACTURE OF SOAP AND CANDLES. does not evolve the disagreeable odor of tallow. It has the strong aromatic odor of nutmeg, melts at from 106° to 124° F., has a specific gravity of -0.995, dissolves in 4 parts of boiling alcohol, with difficulty in cold alcohol, and more freely, but not completely in chloroform, ether, and benzene. According to Koller, 100 parts of it consist of 6 parts of volatile oil of nut- megs, 70 parts of myristin, 20 parts of olein, 1 part of butyrin, and 3 parts of an acid resin. Its iodine degree is, according to Htibl, 31.0. Expressed oil of nutmeg is used in perfumery and in medicine. The principal adulterations are with lard, beef-marrow, tallow, and vaseline, besides coloring substances, such as turmeric, san- ders-wood, etc. The first-named adulterations are, according to Hager, readily detected by triturating 1 part of the fat with about 50 parts of 96 per cent, alcohol, shaking, filtering, washing the myristin remaining upon the filter with alcohol, and drying with pressure between blotting-paper and exposure to the air. In the presence of the above-mentioned fats the filter and the press- paper show grease stains, and the myristin is not pulverulent to the touch, but fatty and smeary. An addition of turmeric is detected by the brown coloration with potash lye. Besides from Myristiea fragrans, the fat is also obtained from several other species of Myristieece. Thje fruit of Myristiea officinalis yields the becuiba tallow, which resembles expressed oil of nutmegs, has a sharp, somewhat sour taste, melts at 116.5° F., and has a specific gravity of 0.956 at 77° F. It is saponin able and yields a crumbling soap. The fruits of 31yristiea Otoba yield the Otoba butter. It is nearly colorless, of a butyraceous consistency, smells, when fresh, of nutmeg, melts at 100.5° F., and contains myristin, olein, and a non-saponifiable body, "ota- bite." Virola tallow is obtained by boiling the peeled kernels of Myristiea sebifera with water. It is yellowish, melts at from 111° to 122° F., is completely soluble in alcohol and ether, and only partially saponifiable. In America, England, and France it is used in the manufacture of candles. Olive-oil is perhaps the oldest known and used for the purpose of making fine soaps, and possesses all the best characteristics for the purpose, yielding a firm white soap with an agreeable odor. FATS, FAT OILS, ETC. 14 n Olive-oil being consumed in large quantities for food, there is much care taken to produce a fine quality for this purpose, and the best of the first and second pressing is generally reserved for table use. In the more southern regions the olives are comminuted to- gether with the kernel, and the paste thus obtained is subjected to pressure; in more northern countries where the olive tree still thrives, but a regular yield cannot be calculated on, only the crushed fruit-flesh is pressed. The kernels remain whole, and after being freed from adhering fruit-flesh by boiling with water are comminuted and extracted. The oil thus obtained is gene- rally brought into commerce under the name of " olive-kernel oilP It is dark green and thickly fluid, and readily deposits a consid- erable quantity of solid fat. The oil chiefly used in the manufacture of soap is the so-called " sulphur-oil." It is prepared from rotten olives and residues from other pressings. It is thickly fluid, contains much stearin, and has a dark-green color. This oil being obtained by extrac- tion with carbon bisulphide, benzene, etc., contains much vege- table mucus, albuminous substances, and a peculiar coloring sub- stance. The oil being very cheap but difficult to bleach, we recommend the following process : The oil is brought into an iron kettle or wooden vat and steam introduced through a perforated serpentine pipe placed upon the bottom. The green color of the oil grad- ually disappears, a slimy dark mass being deposited on the bottom of the vat. The oil is then allowed to rest a few hours, and after washing with two to three per cent, of caustic soda lye of 38° B. allowed to rest for a few days. For manufacturers having no steam at their disposal the fol- lowing process is recommended : Bring 300 pounds of salt water of 10° to 12° B. into a clean kettle and add 1000 pounds of sulphur olive-oil. Then start the fire under the kettle and allow the whole to boil slowly about three hours. A reddish-brown scum forms on the surface which has to be removed, and when this has entirely disappeared cover the kettle and allow the oil to stand in a warm place over night. The next morning bring the supernatant clear oil into a clean wooden vat. In the mean while 144 MANUFACTURE OF SOAP AND CANDLES. mix 20 pounds of peroxide of hydrogen with 3 pounds of sal ammoniac and heat the whole moderately. At the same time have in readiness 200 to 300 pounds of boiling salt water of 5° B. One workman now crutches the oil uninterruptedly, while an- other pours the mixture of peroxide of hydrogen and sal-ammo- niac in a fine stream over the oil. The crutching is continued until brownish streaks appear on the surface. The oil is then washed with the boiling salt water of 5° B. and allowed to rest over night. The oil, though not entirely decolorized, has completely lost its green color and acquired a yellowish shade ; it yields a fine, light soap. Olive-oil is now seldom used alone, the soap becoming, when dry, too hard for general purposes. It is customary to add to it a certain quantity of hemp-seed, rape-seed, poppy-seed, or groundnut-oil ; these oils, being slightly drying oils and producing a softer soap, qualify the olive -oil soap in its consistency. Pure olive-oil is of a pale-yellow to greenish -yellow color and of a mild and agreeable taste. It dissolves sparingly in alcohol, but readily in 1J to 2 J parts of ether and in 3 parts of acetic ether. The cold-pressed oils contain over 70 per cent, of olein ; the remainder is palmitin, with some butine and stearin, and, according to Benecke, a very small quantity of cholesterin. The hot-pressed oils are richer in palmitin. The specific gravity of cold-pressed oils varies between 0.915 and 0.918 at 59° F., while that of the hot-pressed oils is frequently as much as 0.925. The latter deposit granular secretions at 50° F. and congeal at 32° F., while very fine cold-pressed oils become turbid only at 35.5° F., and separate palmitin and stearin at 21° F. The fatty acids separated from olive-oil melt at from 71.5° to 79° F. and con- geal at from 70° to 71.5° F. The saponification equivalent of olive-oil is 191 to 192 and the iodine degree 81.6 to 84.6, and that of the separated fatty acids 86.1. The better qualities of olive-oil are frequently adulterated. An excellent means of recog- nizing pure olive-oil is the iodine degree, as nearly all oils used for adulteration show a higher degree. Olive-kernel oil is readily soluble in alcohol and glacial acetic FATS, FAT OILS, ETC. 145 acid, and has a specific gravity of 0.9202 at 59° F. ; its saponifi- cation equivalent is 188.5 and its iodine degree 81.8. Sesame oil is obtained from the seeds of two varieties of Big- noniacece, Sesamum indicum, L., and Sesamum orientale, L. The seeds are generally pressed three times, the first two pressures being cold and the third hot. The cold-pressed oils are used for table oils and the hot-pressed oils chiefly in the manufacture of soap. The taste of cold-drawn oil, while mild, is less agreeable than that of olive oil. Sesame oil has a fine pale-yellow color and contains a small quantity of a resinous body, which can be extracted by frequent shaking with glacial acetic acid ; it has a specific gravity of 0.922 to 0.924 at 59° F., and congeals at 23° F. to a yellowish-white, transparent, somewhat unctuous mass of the consistency of palm- oil, which, in this state, it very much resembles. The oil con- sists chiefly of olein and very little palmitin, stearin, and myristi- cin. Its saponification equivalent is 190 and that of the separated fatty acids 199.3, the melting-point of the latter being at from 77° to 79° F. and their congealing-point at 72° F. The iodine degree of the oil is from 102.7 to 106, and that of the separated fatty acids from 108.9 to 111.4. In the manufacture of soap only the hot-pressed oil or that obtained from seed of poor quality is used, and also the oil ex- tracted by means of carbon bisulphide or benzene. For bar- soap only the nearly white, thick sedimentary portion deposited in storing sesame oil for some time, and containing much stearin or palmitin, can be used. The liquid portion (as much as 30 per cent.) is employed as an addition to palm-kernel oil, cocoanut- oil, tallow, and palm-oil, with which it yields good soaps. Sesame-oil prepared from mouldy seed has generally a very disagreeable odor, which can, however, be removed to a great extent by boiling the oil upon water with steam, then bringing it into a large reservoir and allowing it to stand. In cooling, much solid fat suitable for bar-soap is separated. The sedimentary portion of sesame-oil is readily saponified, behaving thereby in a manner similar to lard. In boiling with caustic soda lye, the oil is gradually added to the boiling lye, 200 10 146 MANUFACTURE OF SOAP AND CANDLES. parts by weight of lye of 15° B. being generally allowed for 100 parts by weight of the oil. Peanut or groundnut-oil. — This oil is obtained from the fruit of Arachis hypogcea, or the peanut, a leguruine plant. This small creeping plant is indigenous to South America and the coasts of southern Africa and Asia. Since the latter part of the last century it has been cultivated in our Southern States, and in Italy, Spain, and the southern parts of France. The nuts are generally pressed three times, the first cold pressure yielding a nearly colorless oil of an agreeable taste and odor, which is used as fine table oil. The comminuted nuts are then sprinkled with water and subjected to a second cold pressure, which yields an oil also fit for table use, but chiefly employed as an illuminant. The residue is subjected to a third warm pressure, and yields a yellowish-brown oil of a less agreeable taste and odor. It is chiefly used in the manufacture of soap. One hun- dred pounds of peanuts generally yield 30 to 34 pounds of oil. Peanut-oil is somewhat more thinly fluid than olive-oil and contains the glycerides of oleic, palmitic, hypogseic, and arachidic acids. The specific gravity of the finest fresh oil is 0.916 at 59° F., while that of the second and third pressures is as much as 0.920. Peanut-oil belongs to the non-drying oils ; it is quite durable and does not verv soon become rancid. It becomes tur- bid at 37.4° F., congeals at 26.5° F., and solidifies entirely at 19° F. Its saponification equivalent is from 191.3 to 191.6 ; its iodine degree, according to Hiibl, 103, and, according to Moore, 87.3. The separated fatty acids melt at 82° F. and congeal at 75° F. ; their iodine degree is from 95.5 to 96.9. Peanut-oil is used in the manufacture of grain-soap, half- boiled soap, and soft soap. Lyes of not less than 18° B. are used for saponification. The oil in many respects resembles cot- ton-seed oil, but has the advantage that the soaps do not show yellow stains. Two parts of peanut-oil and 3 parts of palm- kernel oil, boiled directly with caustic soda lyes, yield faultless wax grain-soap. Beautiful half-boiled soaps are obtained from 70 per cent, of palm-kernel oil and 30 per cent, of peanut-oil, with caustic soda lye. It is best to boil in a direct way, using FATS, FAT OILS, ETC. 147 pure caustic lye of about 24° B., and afterwards reducing caus- ticity by solution of soda or common salt. As regards soft soaps, peanut-oil is especially adapted for the manufacture of so-called silver soap, or elaidin soap, being prefer- able for this purpose to cotton-seed oil. For cold-stirred soaps the use of peanut-oil is of great advantage. A soap, for instance, of 70 pounds of cocoanut-oil, 30 pounds of peanut-oil, and 60 pounds of caustic soda lye of 36° B. is superior in appearance to a soap in which tallow is used instead of peanut-oil. Peanut-oil is also well adapted for the preparation of soaps for a basis of fine toilet-soaps. For transparent glycerin soaps peanut-oil can- not, however, be substituted for tallow, as the soaps would become too soft. Castor-oil is obtained from the seed of JRicinus communis, L., by pressing in the cold way, or, as it is frequently done in this country, by slightly roasting the seeds before pressing. The oil for medicinal purposes is obtained from the heavy, sound seeds and filtered. A second quality of oil is made from imperfect seed and the residue from the filtration of the first quality. This oil is largely used in the manufacture of toilet-soaps. A third quality of oil, prepared from the sediment, residues, etc., is dark and frequently of a strong and disagreeable odor. It is used as a lubricant and in Turkey red dyeing. Castor-oil is colorless or slightly yellowish, of a mild, with an acrid after-taste and a slight though not disagreeable odor. It is chiefly composed of the glyceride of ricinoleic acid and a small quantity of stearin and palmitin. Its specific gravity varies between 0.95 and 0.97 at 59° F. At 32° F. it deposits a white stearin-like fat, and at 1.4° to • — 0.4° F. congeals to a yellowish, transparent mass. American castor-oil frequently separates stiff fat at 42.5° F., and congeals at from 14° to 10.5° F. The saponification equivalent of castor-oil is, according to Valenta, from 181.0 to 181.5; its iodine degree is 84.4, and that of the separated fatty acids 86.6 to 83.3. The fatty acids melt at 55.5° F. ? and congeal at 37.5° F. The behavior of castor-oil during saponification is similar to that of cocoanut-oil, it being readily saponified by stirring together with strong soda lye. The resulting soap is very white, amor- 148 MANUFACTURE OF SOAP AND CANDLES. phous and transparent, and quite hard, even if it contains as much as 70 per cent, of water, but gives scarcely any lather. It has also the property of dissolving in pure, cold water without ren- dering it turbid or opalescent. It, therefore, seems that sodium ricinoleate is not decomposed by water into an acid salt and basic sebate. Castor-oil is chiefly used in the manufacture of transparent soaps. Cotton-seed oil is obtained from the seeds of the cotton plants, Gossypium herbaeeum, G. arboreum y G. barbadense, and other vari- eties. The seeds having been screened from all dust and foreign substances are freed from adhering cotton by passing them through a machine similar to a gin, only with teeth placed more closely together. They are then brought into the huller, which con- sists of a cylinder armed with steel blades, and surrounded about two-thirds way by a concave box also armed with corresponding knives. The cylinder revolves at great speed, and as the seeds are forced between the knives the pericarps or hulls are broken and forced from the kernels. The mass then falls into a large revolv- ing sieve. The kernels, many of which are broken into fine pieces, pass through the meshes of the sieve and the hulls are carried away. The clean seeds are now crushed between rolls and the resulting meal heated in a pan until the water it contains is evaporated. The hot meal is then placed in wedge-shaped bags of woolen duck, each holding sufficient for a cake. The bags are placed between the sides of wrappers formed of woven horse-hair backed with corrugated leather to facilitate the escape of the oil, and subjected to pressure in a hydraulic press. Some modern presses are so arranged as to do away with the expensive bags and horse-hair mats. The crude oil, as it comes from the press, is reddish or dirty yellowish, thickly fluid, and has a specific gravity of 0.922 to 0.930 at 59° F. It commences to separate palmitin at below 50° F., and congeals between 28.5° and 26.5° F. The process of refining the crude oil, which was kept secret for a long time, consists essentially in a treatment with alkaline car- bonates and caustic alkalies. The tank used is of iron ; it is provided with a mechanical FATS, FAT OILS, ETC. 149 agitator, and its capacity sufficiently exceeds that of the charge of ten tons 7 weight of crude oil and thirty hundred weight of caustic soda lye of 10° to 12° Twadell. The lye, at the tempera- ture of 60° F., is fed slowly by perforated pipes extending over the surface of the oil and distributing uniformly. As the agita- tion proceeds, the lye and oil, which are both cool, mix, and the latter gradually becomes full of black, flocculent particles of soap, caused by the partial saponification of a portion of the oil by the caustic soda lye. The agitation is continued for about half an hour, and at the end of that time a portion is taken out and allowed to stand. If the soapy particles precipitate and the oil is found nearly deprived of color, the operation is then termi- nated. If not, the agitation is continued, more lye being added until the desired discoloration is obtained. The charge of oil is then allowed to stand for twelve or fifteen hours until the "mucilage/ 7 or partially saponified portion of the oil, with the liquid excess of lye used, has settled away. The clear oil is then run off from the brown sediment called " soap-stock/' and the refining completed by washing and bleaching. The soap-stock may be either converted into hard soap, or, by addition of milk of lime, be deprived of any albuminous matter, bleached with chloride of lime, and, by treatment with mineral acid, the refined oil mingled with fatty acids obtained. Refined cotton-seed oil is of a pale straw color, has a pure nutty taste, and a specific gravity of from 0.923 to 0.928 at 59° F. Its saponification equivalent ranges from 191 to 196.5, and that of the separated fatty acids from 110.9 to 111.4. The iodine degree of the oil is from 106 to 108.7, and' that of the fatty acids from 110.9 to 111.4. The separated fatty acids melt at from 95.5° to 101° F., and congeal at from 95° to 100.5° F. In the United States the crude cotton-seed oil is used for lubri- cating purposes, as a substitute for linseed-oil in the manufacture of varnish and in the fabrication of soap ; the refined oil is employed as a table oil, in the manufacture of soap, and largely for the adulterations of other oils. The crude oil saponifies with greater ease than the refined oil ; this is very likely due to the former containing free fatty acids, while the latter is neutral in consequence of the treatment with 150 MANUFACTURE OF SOAP AND CANDLES. lyes in refining. The refined oil saponifies with difficulty even with strong lyes, but readily in combination with easily saponifi- able fats, such as palm-kernel oil, cocoannt-oil, etc. By itself it can only be gradually brought to complete saponification by weak lyes ; the resulting soap has, however, the disagreeable property of being difficult to salt out, and of not completely yielding the excess of water, even with a large addition of common salt. Such soap is so soft and smeary that it can be worked with a shovel, and, on pressing in the hand, yields water. The fresh soap is white, but becomes yellow after drying, and has a peculiar bad odor. In Europe refined oil only is used in the manufacture of soap. It is employed for hard and soft soaps ; however, never by itself, but always in combination with other fats on account of its diffi- cult saponification and the disagreeable odor acquired by pure cotton-seed oil soaps on storing. Soaps manufactured from a large percentage of cotton-seed oil in combination with other fats also show this disagreeable odor ; it can, however, be removed to some extent by boiling the oil with soda lye of 25° B. before use. Commercial refined oil is of a sufficiently pale color for most soaps for which it is used. Where a lighter color is desired the object can be attained by treating the oil with caustic soda lye or with potassium chromate and hydrochloric acid. For hard soaps cotton-seed oil is generally used in combination with palm-kernel oil and cocoanut-oil, it possessing the property of making soaps from these oils soft and delicate. At one time cotton-seed oil was very much liked for smooth white-grain soaps, but the soap-boilers who were first in raptures over the fine results attained, had soon cause for regret when yellow stains made their appearance. These yellow stains are due to a yellow, non-saponifiable, oleaginous body in the oil, which is not de- stroyed by refining with lye and not completely removed by re- peated refining. In France and Italy considerable quantities of cotton-seed oil are worked in combination with peanut-oil into Marseilles soap, though not to the advantage of the product. Cotton-seed oil is also much used for soft soaps. On account of its comparatively large percentage of palmitin it cannot be FATS, FAT OILS, ETC. 151 used in winter for smooth, transparent soft soaps, as they readily become turbid ; in summer it is, however, very suitable for such soaps, they being more solid than with the use of pure linseed- oil. For smooth yellow and smooth white soft soaps cotton-seed oil is well adapted and can be used by itself. For soap with a silver lustre, so-called silver or elaidin soap, it must be previously bleached. It is also used for grained soft soaps, though great care is re- quired in not allowing any soda to reach the soap and using only the best high-graded potash. The property of cotton-seed oil separating palmitin at a few degrees above 32° F., has been utilized in the United States to obtain an oil containing little palmitin, and, therefore, better adapted for the adulteration of olive-oil than the natural refined oil. The separated solid fat is of a lardaceous consistency and is brought into commerce under the name of " cotton-stearin" or " vegetable stearin." According to Muter,* it has a specific gravity of 0.9115 to 0.912 at 100.5° F., is completely soluble in ether and hot absolute alcohol, and by saponification yields 95.5 per cent, of fatty acids belonging to those insoluble in water. Though the fat becomes completely liquid only at 89.5° F., the melted fat does not recongeal after cooling, but forms a yellow oil, which only acquires its original consistency by long cooling at about 40° F. Cotton stearin shows the same disagreeable properties in sapon- ifying as cotton-seed oil, while soaps prepared from it show yellow stains and acquire a disagreeable odor on storing. Almond-oil. — The fat almond-oil found in commerce is gene- rally obtained from small bitter almonds, peach and apricot kernels, and fragments of sweet almonds. It is limpid, thinly fluid, slightly yellowish, nearly inodorous, of a pleasant, mild taste, and belongs to the non-drying oils. Its specific gravity is 0.915 to 0.920 at 59° F. The actual almond-oil congeals at 4° F., peach-kernel oil at 0.4° F., and apricot-kernel oil at about 7° F. * Seifenfabrikant, 1882. S. 411. 152 MANUFACTURE OF SOAP AND CANDLES. The best qualities of almond-oil are used for medicinal pur- poses and for the adulteration of table oil. The inferior qualities are employed for technical purposes, and are especially in much demand for the manufacture of toilet soaps. A cocoa-soap of three-quarters cocoanut-oil and one-quarter almond-oil is very hard and firm and an excellent toilet soap. Besides with peach-kernel and apricot-kernel oils, almond-oil is chiefly adulterated with poppy-oil, sesame-oil, peanut-oil, beech-nut oil, and walnut-oil. Linseed-oil is obtained from the seeds of the flax-plant, Linum usitatissimwn L., by pressure and the aid of heat. Ripe seeds contain 30 to 35 per cent, of oil and those not thoroughly matured less. Commercial seed yields on an average 22 per cent, of oil. Cold-drawn linseed-oil is nearly colorless; hot- pressed oil has a golden-yellow color changing to brown with age. Linseed-oil has a peculiar odor and possesses the most drying properties ot all known oils. On exposure to the air it eagerly absorbs oxygen, soon becoming rancid and thickly fluid ; in a thin layer it dries to a neutral body insoluble in ether. It has a specific gravity of 0.930 to 0.935 at 59° F., and congeals to a solid yellow mass at — 16.5° F. The fatty acids separated from linseed-oil melt at from 52° to 62.5° F., and congeal at about 55.5° F. The saponification equivalent is 189 to 195, the iodine degree 155 to 158, and the iodine degree of the separated fatty acids 155.2 to 155.9. Linseed-oil is soluble in 5 parts of boiling and in 40 parts of cold alcohol and in 1.6 parts of ether. It consists of 10 per cent, of palmitin and myristin, 10 per cent, of olein, and 80 per cent, of linolein, the glyceride of linoleic acid. Many complaints have been lately heard about the adultera- tion .of linseed-oil. The surest way of testing the oil as to its purity is the determination of the iodine degree, that of linseed- oil being the highest of all known oils. A very simple test is to expose the oil to a low temperature ; oil which separates solid fat at a few degrees below 32° F., or congeals, is not pure linseed-oil. Linseed-oil is largely employed in the manufacture of soap in Europe, particularly in Germany, where at times it is so low in price as to be the cheapest fat to use. In combination with other FATS, FAT OILS, ETC. 153 fats it is well adapted for various kinds of soap, and if properly used gives very satisfactory results. Potash soaps from pure lin- seed-oil do not freeze even on exposure to the coldest weather occurring in this country. For summer soft soap it is recom- mended not to use linseed-oil by itself, but to add some oleic acid or cotton-seed oil. For the transparent, pale soft soaps so much in demand at the present time the linseed-oil has to be bleached. A pale oil may be used without bleaching by thoroughly boiling in a lye of 23.5° to 26.5° B. This must, however, be determined by experiment, because a pale linseed-oil cannot be well defined. An oil may appear pale and clear, but when it is boiled the soap rapidly becomes darker in color, while another oil of the same appearance will give a soap that will remain light. A dark brownish linseed-oil, which is not decolorized by lye, cannot be improved by the use of bichromate and acid. Oil of a greenish tinge generally bleaches very light with bichromate and acid. Generally speaking, linseed-oil saponifies with ease. Oil bleached with lye, being entirely neutral, is somewhat more diffi- cult to saponify than crude oil or that bleached with bichromate and acid. It further deserves attention that a thinly-fluid oil like linseed-oil requires lyes of greater causticity than an oil con- taining more solid constituents, as otherwise the soap turns out too soft. An advantage of linseed-oil is that many distilled oleins, which by themselves do not yield a serviceable soap, can be worked in combination with it. When, a few years ago, there was an extraordinary advance in the price of all fats, while that of linseed- oil remained at the old figure, the latter was also used for the fabrication of bar-soaps, half-boiled soaps, and resin soaps. The soda soaps from linseed- oil have the property that, like tallow and olive-oil soaps, they can stand but little common salt. Soaps of about 20 per cent, linseed-oil and 80 per cent, palm-kernel oil, when fresh, were beautiful, but complaint was made that on storing for some time they showed dark stains and acquired a bad odor even in a higher degree than soaps from cotton-seed oil. As linseed-oil does not contain non-saponifiable constituents like cotton-seed oil, it would seem that these defects must be due to incomplete saponification. Soap-boilers very frequently do not take into consideration the 154 MANUFACTURE OF SOAP AND CANDLES. fact that the last portions of most fats and oils saponify with ex- traordinarily great difficulty, and that a soap containing non- saponified fat readily turns rancid. A mixture of 20 parts linseed-oil, 20 parts bone-fat, and 60 parts palm- kernel oil will give a very good winter soap, which will form a larger grain with more certainty than a pure linseed- oil soap. In this case the linseed-oil and bone-fat are first boiled to a curd with a lye of 1 2° B. ; in this way the two fats are simul- taneously bleached. If water-glass is also to be employed, 100 pounds of pure soda lye of 25.5° B. and 15 pounds of water- glass are put in the kettle for each 100 pounds of palm-kernel oil. The curd is added to this and the whole well boiled, after which the palm-kernel oil is added, the soap being from time to time crutched until it boils well in the kettle. The nature of linseed-oil permits the preparation of exceedingly pure soaps. The linseed-oil soaps do not resist the action of the air very well, and should therefore be consumed shortly after being made. Resin soaps manufactured with the assistance of linseed-oil readily become too soft. Cameline-oil or German sesame-oil is obtained by expression from the seeds of the gold-pleasure, Camelina sativa, Cez., or Myagrum sativum, L., natural order Cruciferw. It is golden- yellow, has slight drying properties, and a peculiar taste and odor. Its specific gravity is 0.925 to 0.930 at 59° F. ; it con- geals at — 0.4° F. Cameline-oil, being produced in compara- tively small quantities, is of but little importance, though it is well adapted for the fabrication of soft soaps which do not freeze even on exposure to great cold. Barrel soaps from cameline-oil can scarcely be kept in summer, as they melt below 68° F. Niger-oil is obtained from the seeds of Guizotia oleifera, D. C, cultivated in India. Large quantities of seed are shipped from Bombay to England, where they are expressed. The oil is of a yellowish color and a mild and nutty taste and odor. It has a specific gravity of 0.924 at 59° F., thickens at 17.5° F., forms a transparent yellowish mass at 14° F., and a solid whitish mass at 5° F. In England it is much used in the manufacture of soap. FATS, FAT OILS, ETC. 155 Madi-oil is obtained from the seeds of Madia sativa, Mdt., natural order Composite, indigenous to Chili. Experiments in cultivating the plant in France and Southern Germany proved a failure. The oil is dark yellow and has a peculiar, though not disagreeable, odor and taste. Its specific gravity is 0.928 to 0.935 ; it congeals, according to Winckler, at between 14° and 12° F., and, according to Riegel, at — 13° F. With soda lye it yields a firm, inodorous soap. Hemp-seed oil is expressed from the seeds of Cannabis sativa, L. Large quantities of the oil are brought into commerce from the Russian Baltic provinces. It has a strong odor and a sickly taste. When fresh it is of a greenish-yellow color, but becomes brown-yellow with time. Its specific gravity is 0.925 to 0.931 at 59° F. ; it thickens at 5° F. and concretes at — 16.5° F. The melting-point of the separated fatty acids is at 66° F. and their congealing-point at 59° F. The saponification equivalent of the oil is, according to Valenta, 193.1 ; the iodine degree, according to Hiibl, 143 ; and that of the separated fatty acids, according to Morawski and Demski, 122.2 to 125.2. In boiling alcohol hemp-seed oil dissolves in all proportions ; of cold alcohol it re- quires 30 parts. A solution of 12 parts in boiling alcohol, on cooling, separates stearin. Hemp-seed oil has strong drying properties. It was formerly much used in the fabrication of soft soaps which have a dark green color and can be submitted to intense cold without solidifying. The green soft soaps found at present in commerce are mostly artificially colored linseed-oil soaps. Sunflower-oil. — This oil, obtained by expression from the seeds of several species of Helianthus, is chiefly brought into commerce from Russia. It is limpid, pale yellow, dries slowly, and, when cold-drawn, has an agreeable odor and mild taste. Its specific gravity is 0.924 to 0.926 ; it congeals at about 3° F. The sepa- rated fatty acids melt at 73.5° F. and congeal at 62.5° F. At the present time the larger part of the oil is consumed in Russia itself, where the cold-drawn oil is used as a table-oil and the hot-pressed in the manufacture of varnish and soap. Con- siderable quantities were formerly exported and were readily 156 MANUFACTURE OF SOAP AND CANDLES. taken by soap-boilers, the oil yielding good bar soap and soft soap. Poppy-seed oil is extracted by expression from the seeds of Papaver somniferum. It has a slight odor and mild taste ; is nearly colorless or pale golden-yellow and limpid. The oil of the second pressure is darker. Poppy-seed oil has a specific gravity of 0.924 to 0.937 at 59° F. and congeals at —0.4° F. The separated fatty acids melt at 69° F. and congeal at 62° F. The saponification equivalent is 192.8 to 194.6; the iodine de- gree 134 to 136. Poppy-seed oil is chiefly used as a table-oil and in oil painting. On account of its high price it is not much used in the fabrica- tion of soap ; the thick sedimentary oil serves for the fabrication of soft soaps. Colza-oil. — Under this name are known the oils obtained from different varieties of Brassica. Their properties agree in all principal points, the specific gravity varying between 0.9128 and 0.9175 at 59° F. and the congeal ing-point between 28.5° and 14° F. The saponification equivalent is 177 to 179, the iodine de- gree 100 to 103.6, and that of the separated fatty acids 96.3 to 99.02. The colza-oils consist chiefly of the glycerides of oleic, stearic, and brassic acids, and contain, according to Allen and Thompson, one per cent, of non-saponifiable substance. Their very low saponification equivalent is due to the percentage of brassic acid. The color of colza-oils is pale or dark brown- yellow, the product of the first pressure being somewhat paler than that of the second pressure. When fresh the oils are almost inodorous, but acquire a peculiar odor by age. They have an acrid taste, especially those of the second pressure. Before the introduction of petroleum colza-oils were largely used for illuminating purposes, but at present they are chiefly employed as lubricants. They are seldom used in the manufac- ture of soaps, with the exception of the thick sedimentary oils which are frequently utilized for soft soaps. They saponify with difficulty, and the soft soaps prepared from them break up at a moderate cold. With soda lye colza-oils yield a poor, crumbling soap. FATS, FAT OILS, ETC. 157 Utilization of sedimentary oils. — Large lots of sediment from oil reservoirs are frequently offered to soap-boilers. These sedi- mentary oils generally constitute a dark and smeary mass, and are suitable for the fabrication of soft soaps and bar soaps which are very valuable for fulling. The oils can also be used for resin soaps, the strong odor adhering to them covering to some extent that of the resin. The oils are worked in various methods ; some boil them to grain and add a small quantity of the resulting soap to each boiling of soap, while others add a small quantity of the sedimentary oil directly to the soap-stock, which can be very well done, for instance, with half-boiled soap. It depends, however, more or less on whether the sedimentary oil is comparatively pure and not too old. Another method yielding an excellent product consists in boiling the sedimentary oil upon strong salt water until the clear oil free from scum floats on top. One thousand pounds of the oil are brought into an open kettle, together with 800 pounds of water and 60 pounds of salt, and boiled 10 to 12 hours. The kettle is then allowed to stand un- covered for 24 hours, when the clear oil on the top is drawn off. Beneath the clear oil is a layer of slime mixed with hulls of seed, etc. The oil retained by this is gradually separated by filling petroleum barrels half full with this slime, adding salt water, and after covering the barrels exposing them to the sun. This process is still better if executed with steam. Fatty Acids and Resin. The use of fatty acids in the fabrication of soaps is based upon a much more simple chemical process than that which takes place in the saponification of neutral fats, as no previous splitting into glycerin and fatty acids is required, and the fatty acids pos- sess the pro'perty of expelling the carbonic acid from alkaline carbonates and combining with them to soap. With the use of fatty acids the preparation of lyes might, therefore, be saved and saponification effected with solutions of alkaline carbonates, if it were not for the strong effervescence produced by the escape of the liberated carbonic acid ; hence the lve can onlv be verv gradually added to the fatty acid in the kettle, as otherwise a boil- 158 MANUFACTURE OF SOAP AND CANDLES. ing over might easily take plaee. For this reason lyes partly caustic, though less so than those employed for neutral fats, are always used without fear of suffering a loss of alkaline carbon- ates. While in working neutral fats they are first brought into the kettle and the lye is gradually added, the process is the re- verse with fatty acids, i. e., the fat is added to the lye. If sa- ponification were effected as with neutral fats, by the gradual ad- dition of lye, the latter would be at once fixed by the fatty acid, and solid lumps would be formed which could only later on be dissolved with difficulty by boiling with an excess of lye. The use of fatty acids in the fabrication of soap is perhaps as old as the manufacture of stearin. In the patent granted in 1825 to Gay-Lussac and Chevreul, for the separation of fatty acids and their application to the manufacture of candles, it is stated : " The liquid bodies separated are to be converted into soap."* The crude oleic acid of stearin manufactories was the only fatty acid used in the fabrication of soap until the fatty acids regained from the wash-waters of cloth mills and other textile industries were brought into commerce under the name of " fuller's fat." The high price of glycerin a few years ago induced several stearin manufacturers to saponify neutral fats in order to obtain the glycerin and to sell the fatty acids to the soap-boiler. In this manner fatty acids of palm-oil, palm-kernel oil, olive-oil, and bone-fat came into commerce. They were no doubt prepared by saponifying the fats by De Milly's autoclave apparatus (see page 48) and distilling the separated fatty acids with superheated steam to give them a beautiful white appearance. Since the neu- tral fats contain at the utmost 95 per cent, of fatty acids, the latter, when pure, must give a correspondingly higher yield than the neutral fats from which they are separated. In regard to their ability in absorbing water, salts, etc., soaps from fatty acids show the same behavior as the soaps from the corresponding neu- tral fats. Another fatty acid — the so-called " rapoMn" — has been recently offered to soap-boilers. It is a clear, dark red, nearly inodorous oil, and is very likely prepared from residues * Brevets d'invention 41, p. 392. FATS, FAT OILS, ETC. 159 obtained in refining colza-oil. It is well adapted, either by itself or in combination with linseed-oil, for the fabrication of summer soft soaps, though only where no objection is made to their brown color. Of the above-mentioned fatty acids it will be only necessary to give a full description of oleic acid, also called olein or ela'in, and of fuller's fat. Oleic acid. — In the manufacture of stearin the fat, as previously mentioned, is saponified for the separation of the glycerin, and the resulting mixture of fatty acid is separated by pressure into a solid and liquid portion. The cakes obtained by the first cold pressure are again subjected to a second warm pressure. The resulting solid white mass is known as " stearin," though scien- tifically the term is incorrect, since the product is not the glycer- ide of stearic acid, but essentially a mixture of stearic and pal- mitic acids. The liquid portion running off by the first cold pressure is " oleic acid/ 7 which, however, contains a considerable quantity of stearic and palmitic acids, and, with previous autoclave saponifi- cation, some dissolved neutral fat. By long storing in a cool cellar, or better, by cooling with a cold-air machine, the greater portion of the solid fatty acids separates out and is extracted by a filter-press or other filtering arrangement. The finally result- ing clear, oleaginous fluid forms the " oleic acid." In commerce a distinction is made between " saponified" and " distilled" oleic acid, the latter being less suitable for soap-making purposes than the former. To fully understand this distinction we must bear in mind that in the fabrication of stearin (fully described in Chapter II.) several methods are employed for the saponification of the fats, chiefly the so-called autoclave process and acidy sapon- ification and subsequent distillation. Saponification by means of lime, which is the oldest method, has been entirely abandoned, chiefly on account of the large consumption of sulphuric acid re- quired for the decomposition of the lime-soap formed. The principal source of saponified oleic acid at the present time is the autoclave process, i. e. y saponification under pressure in a closed, vessel with 2 to 4 per cent, of lime. For the separation of the latter sulphuric acid is also used, but less lime being employed 160 MANUFACTURE OF SOAP AND CANDLES. than in ordinary saponification by means of lime, correspondingly less sulphuric acid is required for the decomposition of the lime- soap. Acidy saponification is effected by bringing the heated fat for a shorter or longer period in contact with more or less concen- trated sulphuric acid and then boiling for some time with water and steam. After allowing the whole to rest for a while, the mixture of fatty acid separates on the top. The aqueous layer beneath, which contains the glycerin and sulphuric acid in solu- tion, is then removed and the fatty acid mixture again boiled with water and steam. The whole is then allowed to rest for some time, after which the fatty acid collected on top is lifted off and submitted to distillation by means of superheated steam. By the repeated boiling with water and steam the sulphuric acid is generally completely removed, but any trace of it remaining is eventually expelled by the subsequent distillation. If, therefore, the opinion held by many soap-boilers, that the poor quality of distilled oleic acid is due to a content of sulphuric acid, may be regarded as erroneous, the question remains, what has brought distilled oleic acid into disrepute ? It was formerly generally held that the defects were due to distillation, as oleic acid could not be distilled without suffering decomposition. This opinion has, however, been refuted by Bolley and Bergmann's in- vestigations. They found that oleic acid distils over unaltered in a current of steam of 482° F., but that products of decomposi- tion make their appearance at a higher temperature. In many stearin manufactories distillation is carried on at too high a tem- perature, they being forced to do this on account of the fat not being completely saponified and containing too much neutral fat. The poor quality of distilled oleic acid may, therefore, be due to products of decomposition formed under the influence of too high a temperature, and also to a content of non-saponifiable products originating from the treatment of the fat with sulphuric acid. Formerly, when acidy saponification was generally carried on by allowing large quantities of concentrated sulphuric acid to act a long time upon the fats, a portion of the oleic acid was always destroyed, while the remainder w T as so changed as to render it almost unfit for the manufacture of soap. Besides, the oleic acid FATS, FAT OILS, ETC. 161 always contained a considerable quantity of non-saponifiable, paraffin-like combinations (hydrocarbons). But this has been changed since experience has taught that fats can be saponified by leaving them a very short time in contact with concentrated sul- phuric acid and completing saponification by boiling with water acidulated with sulphuric acid. Stearin manufacturers using this process of acidy saponification now furnish oleic acid suitable for soap-making purposes. It may be even said that the greater part of the so-called saponified oleic acid at present found in commerce is actually distilled, as many factories saponifying in autoclaves subsequently slightly acidulate the fatty acids obtained and sub- mit them to distillation. With many samples of oleic acid it is, therefore, almost impossible to decide by which process of sapon- ification they originated, while others by their acrid odor at once indicate their production by distillation. The best means of examining oleic acid is to test it in regard to its saponifying ability, i. e., to determine how much non- saponifiable substance it contains. This is done in exactly the same manner as examining for mineral-oils or resin-oils (see page 102). Saponify the oleic acid with alcoholic soda lye, mix the resulting soap with sand, evaporate the alcohol in a water- bath, wash the residue with petroleum spirit, and remove the latter from the extract by evaporating at 122° F. The residue gives the non-saponifiable, paraffin-like combinations. A method somewhat less exact, but sufficiently accurate for technical purposes, is by directly determining by titration the quantity of saponifiable substance. Oleic acid requires 19.87 per cent, of potassium hydroxide, and as palmitic acid requires 21.89 per cent, and stearic acid 19.73 per cent., we will not be far wrong in assuming 20 per cent, for oleic acid. Mix 1 gramme of oleic acid with 20 to 25 cubic centimetres of alcohol, color the mixture yellow with a few drops of phenol-phthalein, and titrate with potash lye containing 20 grammes of potassium hydroxide to the litre, until the appearance of a red coloration. With absolutely pure oleic acid, 1 gramme would almost exactly require 10 cubic centimetres of this lye for saturation. Such oleic acid is, however, not found in commerce, it generally con- taining at the utmost 97 or 98 per cent, of saponifiable substance. 11 162 MANUFACTURE OF SOAP AND CANDLES. It would therefore require 9.7 or 9.8 cubic centimetres of the lye, so that 0.1 cubic centimetre of the latter always corresponds to 1 per cent, of oleic acid. Oleic acid containing less than 95 per cent, of saponifiable substance cannot be designated as good, though it is found in commerce with more than 20 per cent, of non-saponifiable substance. Oleic acid is used for grain-soap, smooth ela'in soap, and, in connection with linseed-oil, for transparent soft soap. The latter being brown, the demand for it has, however, much abated since the introduction of light-colored soft soaps. Oleic acid is much liked for soaps to be used in the textile industries. Hard oleic acid soaps are frequently used in place of olive-oil soaps. The fatty acid mixture separated by hot pressure in stearin factories is of a lardaceous consistency and is generally known as " soft fat" or " roargarin." It is generally added to crude fatty acids before subjecting them to pressure, though it is sometimes worked into soap. It yields excellent grain-soaps, but is espe- cially adapted for smooth ela'in soap, so-called silver soap. Under the name " white elain," a white fatty acid of larda- ceous consistency is brought into commerce from Holland. A few years ago, when the price of tallow ruled very high, it was frequently employed, in connection with cocoanut-oil and palm- kernel oil, in the manufacture of white grain-soap. This white elain must not be confounded with the " solid white olein" which will be referred to under fuller's fat. Fullers fat — The oldest method of recovering the fatty sub- stances from the soap-waters of cloth manufactories, spinning establishments, dye-houses, etc., consisted in leading the water running from the wash-tubs into special cisterns, mixing it there with milk of lime, then letting it settle until it had cleared off. After removing the supernatant liquid, the slimy sediment was taken out, strained through coarse canvas for removing sand, hair, etc., and well dried. The slime having assumed a doughy consistency, it was moulded into pieces of the size of half a brick and dried in the air. The dried pieces, called " suinter," from the French word " suint" (wool sweat), were then distilled in re- torts for the fabrication of illuminating gas. This method of FATS, FAT OILS, ETC. 163 recovering the fat has, however, been abandoned, as it had many defects, and the process with sulphuric acid substituted for it. The soap-water is conducted into reservoirs of pine wood. Such a reservoir is about 9 feet long, 5J feet wide, and 5 feet deep, and holds about 1850 gallons. Sulphuric acid is added, and, in order to hasten separation, steam is introduced for from 1 to 2 hours. The quantity of sulphuric acid to be used depends chiefly on the amount of alkali in the soap-water ; a slight excess is, however, always allowed, since by it a quicker and more com- plete separation, and, in consequence thereof, a more compact mass is obtained. On an average, 55 pounds of sulphuric acid of 66° Baume suffice for a complete decomposition of 1850 gallons of soap-water, and will yield, according to the time allowed for draining off in the filtering basins, from 430 to 450 pounds of fatty matter. The filtering vessels consist of baskets lined with coarse hemp cloth. When the caseous, doughy mass is sufficiently drained off and has acquired the plastic consistency required for forming it into press-cakes, it is wrapped up in hemp cloths and in the usual way laid between plates in a hydraulic press and pressed, at first cold, and later on with admission of steam, until the fluid contents are completely exhausted. A solid residue, about one-half of the mass, remains in the press-cloths, while an equal quantity of watery fat runs into the reservoir. This is also reduced to about one-half its weight by the various operations of the refining process, so that the average yield will be about 25 per cent, of salable fuller's fat. The crude hydrous fat in the press reservoirs yet requires re- fining and dephlegmation. For the purpose of refining the fat is placed in copper tanks 3J feet in diameter and 5 feet deep, which are fixed in iron casings. According to the greater or lesser purity of the fat, ^ or \ of its volume of water and 2 to 3 per cent, of its weight of sulphuric acid of 66° B. are added and the whole is heated by direct introduction of steam to moderate boil- ing, which is kept up for one hour. The steam is then cut off, the mass allowed to settle for a few hours, and the lower turbid and slimy stratum drawn off. The liquid running off is replaced by an equal quantity of pure water, and the whole heated to moderate boiling in order to remove adhering sulphuric acid. 164 MANUFACTURE OF SOAP AND CANDLES. The whole is then allowed to settle for 12 hours, when, after re- moving the aqueous stratum, the clear mass of fat is drawn off. The fat thus obtained still contains a considerable quantity of water, and is freed from it by bringing it into a kettle provided with a copper or iron coil through which steam circulates. The fat thus obtained forms a thickly-fluid, oily mass of a brown to black color and disagreeable odor, and is brought into commerce under the name of " fuller's fat." It is much used in the manufacture of soap, though never by itself, but always in combination with other fats, especially with palm-kernel oil and resin. It is much liked for soaps used in the textile industries. It readily saponifies with tank-lye of 18° to 24° B. ; it must, however, be strongly salted out, and is best further boiled upon a second water, whereby it yields a good grain-soap of fair washing power. It shows, however, varying colors, every lot of fat yield- ing in this respect a different product. In buying fuller's fat it is well to test it, as it frequently con- tains much dirt and water, and recently complaints have been made about mineral oil being found in it. The latter is very likely not due to intentional adulteration, but to the fact that at the present time mineral oils are much used in spinning establish- ments and reach the wash-waters. Fuller's fat consisting chiefly of fatty acids can be readily distilled with superheated steam. The fat thus refined is com- mercially known as " solid white olein." It readily saponifies with tank-lye of 20° to 25° B., and yields a beautiful, firm grain-soap of a silver lustre and a good odor, which is very much liked as a fulling soap. This distilled fat can also be advantage- ously used in the fabrication of white grain-soap. Resin or colophony. — Resin is obtained from turpentine, a mix- ture of oil of turpentine and resin. In regions rich in pine forests, especially in France and the United States, the trees are " boxed," L e., excavations are made into the trunks of the trees about six inches or more above the roots. The crude turpentine exuding is collected in barrels and transferred to stills. If the turpentine is distilled with water, oil of turpentine passes over and a resinous mass remains as a residue which is known as " boiled turpentine." If this is melted without water until it FATS, FAT OILS, ETC. 165 becomes clear, then the colophony or resin remains. The grade of resin depends first upon the quality of the turpentine, and, second, upon the skill in distilling. " Virgin turpentine," if skillfully distilled, will yield what is known as " window-glass resin/' of which there are two or three grades. If by any means water gets into prime resin, it becomes opaque. This accidental addition of water must take place after the resin has been drawn off from the still. " Yellow-dip turpentine," which is the running of the second and subsequent years from the trees, yields the medium grades of resin, while the "scrapings," i. e., the inspissated gum from the tree facings, yield an inferior resin, from very dark to almost black. All varieties of resin are brittle, of a conchoidal fracture, and a more or less strong odor of oil of turpentine. The specific gravity of colophony is 1.08. Common resin is soluble in alcohol, ether, and in fat and vola- tile oils; it melts at 272° F., and, when heated to a higher tem- perature, becomes darker. By exhausting colophony with cold alcohol, sylvic acid (C 20 H 30 O 2 ) goes into solution, and on evapo- ration crystallizes in flat needles, melting at 264° F. and solidi- fying to an amorphous mass. Besides sylvic acid colophony contains the isomeric but amorphous pinic acid. A third isome- ride, called pimaric acid, exists in galipot, the resin of Pinus maritima. Besides its application in soap-making common resin finds varied uses. The most important of these are the manufacture of varnishes, lacquers, cements, brewers' and bottlers' pitch, and of lubricants for wagons and machinery. Though common resin cannot be called an actual fat, it can be readily saponified with strong lyes. Formerly it was much used in combination with tallow and palm-oil for grain-soaps ; at the present time it is, however, chiefly employed in combination with palm-kernel oil, cocoanut-oil, bone-fat, olein, fuller's fat, and cotton-seed oil. A method of fabricating resin grain-soaps, formerly much in use, was to boil the tallow to a clear paste with an average lye of 13° to 15° B., then salt out, amd, after removing the sub-lye, boil the grain clear upon the lye of 24° to 25° B. required for the 166 MANUFACTURE OF SOAP AND CANDLES. resin. The comminuted resin was then added and saponified over a moderate fire. After further boiling the thoroughly fitted and separated soap was slightly ground with water. Saponifica- tion of the resin with strong lyes is necessary, because, with the use of weak lyes, the formation of froth would be promoted by the large amount of moisture naturally brought into the soap by them. A soap from 100 parts of tallow and 60 to 100 parts of resin was also frequently prepared by boiling the tallow saponi- fied with lye of 15° B. to a paste quite free from froth, adding the resin together with the corresponding quantity of lye of 24° B. and boiling like Eschweg soap. The soap was then slightly fitted and separated with caustic soda of 36° to 38° B. until strong " wetting' 7 appeared. At the present time, with the use of palm-kernel oil, etc., where stronger lyes are employed from the start, the preparation of good resin grain-soap is much simpler ; care must, however, be had not to add too much grain-paste from former boilings, whereby much injurious salt is frequently introduced into the soaps. The fitting of resin grain-soap must always be done suc- cessively and carefully adjusted ; and be rather light. A resin grain-soap from 100 parts of palm-kernel oil and about 30 parts of resin is frequently prepared by boiling the palm-kernel oil to a clear paste with lye of 24° to 25° B. The fire being mode- rated, the comminuted resin is then added together with the re- quired quantity of lye of 24° to 25° B. and allowed to thor- oughly combine. After the continuing boiling for some time, the soap is strongly fitted, salted out with caustic soda lye of 38° B., and ground with water until it thoroughly " Avets." For the ad- vantageous use of caustic soda in the preparation of such soaps, dissolve together with 100 pounds of 74 to 76 per cent, caustic soda about 25 to 28 pounds of calcined soda. According to another method, with the use. of half-bone fat and half palm-kernel oil and 25 to 30 per cent, of pale resin, the bone-fat is boiled to grain with tank-lye of 13° B. In the mean while the palm-kernel oil and resin are boiled to a clear paste with caustic soda lye of 20° to 23° B. This paste is then added to the grain from the bone-fat, and the whole, after boiling until free from froth, is allowed to stand for several hours, when FATS, FAT OILS, ETC. 167 the soap is ladled out. The precipitate remaining in the kettle is then salted out and crutched into the soap in the frames. This method, which yields a solid soap, requires, of course, pure fats and pale resin. According to the American method, resin soaps from 100 parts fat and 100 parts resin are generally prepared by saponifying tallow and about 10 per cent, of palm-oil with lye of 13° B., salt- ing out and boiling the grain clear ; after removing the sub-lye, the lye of 25° B. necessary for the saponification of the resin is added and then successively the pulverized resin. The whole is then allowed to boil for some time, adjusted to "touch," and again separated. The soap is then thoroughly ground and allowed to rest for some time in the well-covered kettle. The soap is then brought into the frame and a strong solution of crystallized soda (4 to 5 parts by weight to 100 parts by weight of soap) crutched in, whereby the phlegm is absorbed and the soap becomes firmer ; and is then crutched cold. A yellow or reddish-yellow color is generally given to light resin grain-soap by boiling some crude palm-oil with it. For the fabrication of dark resin grain-soaps, palm-kernel oil, wool fat, fuller's fat, kitchen fat, etc., with an addition of Ameri- can F resin, are generally used. The fats are first saponified, the pulverized resin and the corresponding quantity of lye of 24° B. added, and, after thoroughly fitting and salting out, the grain is boiled clear and then ground with hot water until the sub-lye commences to paste. For marbled soap, the grain is brought into the frame, drawn through with a rod, and well covered. For very dark soaps some diluted sugar color is added, or some pitch boiled with the soap. In many regions, besides resin grain-soap, light and dark paste soaps with a varying per cent, of resin are manufactured, which are frequently filled with water-glass, talc, clay, etc. These soaps are mostly prepared by boiling cocoanut-oil or palm-kernel oil (for dark soaps with an addition of 5 to 10 per cent, of fuller's fat) with caustic soda lye of 23° B. ; the addition of resin varies generally between 10 and 20 per cent. The method of boiling* is, as a rule, that of an ordinary cocoanut-oil soap. The oil and resin are saponified with the lye, and when the paste is clear the 168 MANUFACTURE OF SOAP AND CANDLES. fire is moderated and a corresponding quantity of potash solution of 28° to 30° B. added. Combination being established, the mass is shortened with salt water of 20° B., and finally 15 to 20 per cent, of heated soda water-glass, into which a few pounds of talc have been stirred, is crutched in. The soap has to be crutched in the frame until quite cold, as otherwise it readily marbles. A too strong fitting has to be avoided, as otherwise the soap would show strong efflorescence, especially in the cold season of the year. Besides the above-mentioned resin soaps, which are prepared in the warm way, many soap-boilers manufacture them by the cold way. The principal materials used are tallow, palm-oil, cocoanut-oil, and palm-kernel oil ; the addition of resin varies between 10 and 100 pounds to 100 pounds of the fat used. The preparation of these soaps is effected in a manner similar to that of cocoanut-oil soap in the cold way. Fat and resin are melted together and then stirred together, at 122° to 189.5° F., with caustic soda lye, the quantity of which depends on that of the resin used. Combination being established, the soap is brought into the frame and the latter covered. Resin finds a further and important application in the manu- facture of the various smooth and artificial grain soft soaps. The resin — about 5 to 15 pounds to 100 pounds of oil — is either at once brought into the kettle together with the oil and saponified with it, or it is added together with the required lye of 30° B. to the soap when boiling up, finished, and combined with it by crutching. The latter method, which is chiefly used and can be particularly recommended for glycerin soft soap and similar varieties, gives paler soaps and a somewhat larger yield, though refitting is neces- sary after the addition of the resin. On the other hand, by boil- ing the resin with the fat, the soap is somewhat darker and the yield somewhat less, but refitting being omitted, the work is quicker and surer. By an addition of resin pure soft soaps are rendered cheaper, give a better lather, and become more lustrous ; they are, however, considerably softer, and it is, therefore, neces- sary to use about 20 to 30 per cent, of soda lye of about 24° B., the quantity depending on the season of the year ; more being used in summer and less in winter. It is sometimes desirable to have a very light resin. This can FATS, FAT OILS, ETC. 169 be obtained by artificial bleaching. Melt the resin in a kettle and allow it to stand until all dirt has settled on the bottom. The clear resin is then ladled into another kettle and to each 100 pounds of it are added 20 pounds of common salt solution of 9° B. The whole is then boiled for one hour, when the fire is dimin- ished. As soon as ebullition ceases the resin settles on the bot- tom, while the salt lye separates as a brownish fluid on the top. This salt lye is drawn off, the salt water renewed, and the whole again boiled. If the resin is not sufficiently decolorized, the operation is repeated for the third time. 170 MANUFACTURE OF SOAP AND CANDLES. CHAPTEK VI. ALKALIES. By the term " alkalies" are designated the oxides of a small group of metals which are distinguished by being lighter than water, oxidizing readily in the air, and decomposing, at an ordi- nary temperature, water, with the development of hydrogen gas. The oxides of these metals—the alkalies — are the strongest bases known ; they combine with water to hydrates, forming the so- called caustic alkalies. These have a caustic, lye-like taste, de- stroy the skin and all organic tissues, and are readily soluble in water. Their solutions color reddened litmus tincture blue, the coloring matter of violets and roses, green, and that of turmeric, brown ; they show, as it is termed, an alkaline reaction. From the air these hydrates absorb water and carbonic acid. Two of these alkaline hydrates are extensively used for tech- nical purposes, potassium hydrate (KHO) or caustic potash, and sodium hydrate (NaHO) or caustic soda. The usual method of converting the alkaline carbonates into alkaline hydrates is by means of slaked lime (calcium hydrate CaH 2 2 ). By bringing together solutions of alkaline carbonates with slaked lime a con- version takes place, by the carbonic acid of the alkali combining with the calcium oxide, to calcium carbonate, which, being insol- uble in water, falls to the bottom, while the alkali combines with the hydrate of the lime and remains in solution : — + 2NaHO Caustic soda. + 2KHO Caustic potash. Following hereto we give the manner of manufacture and the properties of the various kinds of alkaline carbonates and caus- Na 2 C0 2 + CaH 2 2 = = CaC0 3 Soda. Calcium hydrate. Calcium carbouate. K 2 CO + CaH 2 2 = = CaC0 3 Potash. Calcium hydrate. Calcium carbouate. ALKALIES. 171 tic alkalies found in commerce, commencing with soda, which, next to common salt, is the most important of all mineral salts. Soda. — The soda brought into commerce is known, according to its derivation, as (1) Natural soda and (2) Artificial soda. 1. Natural soda. — Sodium carbonate is widely distributed in nature as a constituent of many minerals and mineral waters ; it further exists in the soda lakes of Hungary, Egypt, and America, and in the water of the geysers of Iceland. It is occasionally found native as an efflorescence on the soil, for instance, on the alkali plains of North America, on the steppes between the Black and Caspian seas, in Mexico, South America, etc. The oldest-known occurrence of natural soda is in Lower Egypt, where, in the neighborhood of Memphis and Hermopolis, a variety of soda is obtained from some shallow lakes, which is known as " latroni," and contains besides sodium carbonate, Glauber's salt, common salt, sand and water. Somewhat different from this is the " trona," an efflorescence on the soil occurring also in Egypt, which mostly contains sodium sesquicarbonate. In Columbia a variety of soda known as " urao" crystallizes from a lake during the hot season of the year ; it is also a sesqui- carbonate. Extensive deposits* of the chloride, sulphate, and carbonate of soda are found at many points in the arid regions of the United States, and may be had for the trouble of gathering. These deposits occur in the desiccated beds of ancient lakes in Nevada, Arizona, Western Utah, and portions of California and New Mexico. There are certain lakes, also, which are valuable brines. In the basins where evaporation has been nearly or quite com- plete, the alkaline salts occur either at the surface, when they ap- pear like fields of snow, frequently many square miles in extent, or they may be concealed beneath the layers of fine mud known as playa deposits. Again, large areas in Nevada and Arizona are white with alkaline salts that have been brought to the sur- face in solution and deposited when the waters evaporated. These efflorescences are frequently rich in sodium carbonate, sul- * I. C. Russel, in United States Independent Journal, 1886. 172 MANUFACTURE OF SOAP AND CANDLES. phate and borate, and have been utilized to a limited extent at a few localities. The lakes of the Far West, which are likely to become of commercial value on account of the alkaline salts they contain, are Great Salt Lake, Utah ; the Soda lakes near Ragtown, Nevada ; Mono and Owen's lakes, California ; and Summer and Abert lakes, in Oregon. All of these are without outlet, and owe their high percentage of mineral matter to the concentration by evaporation of the waters of streams and springs with which they are supplied. Their chemical composition is shown in the following table : — ' 1 2 3 4 5 Great Salt Soda Lake, Mono Lake, Owen's Abert Lake. Utah, Nevada, California, Lake, Lake, 1869. 18S3. 1S83. California, 1876. Oregon, 1883. Sodium 49.690 40.919 18.100 '21.650 2,773 Potassium . 2.407 2.357 1.111 2.751 10.637 ■ Calcium 0.225 — 0.278 trace — Magnesium 3.780 0.245 0.125 trace 0.002 Lithium trace — — trace — Chlorine 83.946 40.851 11.610 13.440 8.220 Bromine trace — — — — - Carbonic acid — 16.584 11.465 13.140 4.547 Sulphuric acid 9.858 11.857 6.520 9.362 0.497 Phosphoric acid — — — trace — Nitric acid . — — — trace — Boracic acid trace 2.026 0.153 trace — Silica . — 0.278 0.268 0.164 0.064 Alumina — — — trace — Total parts per thousand 149.906 115.117 49.630 60.507 26.740 The analysis of No. 1 was made by Prof. O. D. Allen, of Nos. 2 and 3 by Dr. M. T. Chatard, of No. 4 by Dr. Oscar Loew, and of No. 5 by Dr. T. W. Taylor, all connected with the United States Geological Survey. It is safe to predict that Great Salt Lake will not only be of great value in the near future on account of the immense quanti- ties of common salt it is capable of producing, but also for the sodium sulphate it contains. When the temperature of the lake- water is reduced to 20° F., the separation of sodium sulphate takes place as a flocculent precipitate, which increases in quantity ALKALIES. 173 with decrease of temperature. This should suggest to manufac- turers a method of obtaining the salt and on a large scale. When the temperature of Great Salt Lake is lowered on the approach of winter, its waters become opalescent, owing to the precipitation of sodium sulphate in an extremely finely divided state. During the winter months the temperature of the air in the region of the lake sometimes falls to 20° or more below 0° F., and at such times the separation of sodium sulphate takes place on an im-. mense scale, and it is thrown upon the shore in thousands of tons. The amount that could be gathered at such times is practically unlimited. As railroads now touch the shore of the lake, the problem of supplying this salt to manufacturers is simplified. The Soda Lakes, situated on the Carson Desert, Nevada, about fourteen miles east of Wadsworth, have already been uti- lized as a source of sodium carbonate which is shipped to San Francisco. These lakes occupy the craters of extinct volcanoes, and the mineral matter they contain has been derived mainly from the leaching of the lopilli and lacustral deposits surround- ing them. Mono and Owen's lakes are now quite accessible by rail, and are capable of furnishing immense quantities of sodium sulphate and carbonate. It has been estimated by Dr. Oscar Loew that Owen's Lake contains about twenty-two million tons of sodium carbonate and a little less than one-third of this amount of sodium sulphate. It is estimated that Mono Lake contains — Potassium chloride „ 8,998,856 tons. Sodium chloride . . . . 73,524,285 " Sodium sulphate 40,636,089 " Sodium carbonate 78,649,194 " Total of salts in lake . . . 201,808,424 " Summer and Abert lakes, situated in Southern Oregon, are remote from railroads, but are extremely valuable brines on ac- count of the potash salts they contain. These lakes occupy depressions in the bed of an ancient lake of large size, now desic- cated, and are very similar in character. Abert Lake alone has been analyzed, but it is probable that its companion has nearly an identical composition. Abert Lake is about fifteen miles long 174 MANUFACTURE OF SOAP AND CANDLES. by five miles broad, and has an average depth (varying with the seasons) of approximately ten feet. Summer Lake is perhaps a third larger and is also shallow, but its average depth is unknown. The percentage of potassium salts in Abert Lake is greater than in any other lake the composition of which has been published, amounting to five-sevenths of the total of solids in solution. With these abundant resources at hand, the alkali industry of the Far West unquestionably has a great future, and it is to be hoped that it will soon receive the attention that its importance demands. The occurrence of soda as an efflorescence in the great Hun- garian plain was already known to the Romans. The sand of the Theiss plain consists chiefly of minerals containing sodium, which, being disintegrated by the action of Hme, water, and air, give rise to a thick crystalline layer of salt which contains 6 to 15 per cent, of sodium carbonate, and is known as " Szekso." It is found in greatest abundance in the region between the Danube and the Theiss and in the Debreezine forest from Kecskemet south to Szeged in. By refining this szekso a product containing 70 to 75 per cent, soda is obtained. Formerly the principal source of commercial soda was the ashes of plants growing on salt plains, near salt springs, and on the border of the sea. Plants growing in the sea itself are not suitable for this purpose, as they contain but a small quantity of alkaline carbonates, and they are principally worked on account of their content of potassium sulphate and potassium chloride, and especially of iodine. The preparation of soda from the actual soda plants, which are found along the borders of the sea to within a certain stretch into the interior of the country, is very simple, consisting only in the incineration of the plants. The industry was, and is partially at the present time, carried on on the coasts of Scotland and Ireland, but chiefly on the Mediter- ranean, in Sicily and Sardinia, and on the Spanish coast in the province Valencia, in Morocco and in Armenia, and the South Russian steppes. The best soda of this kind was the Spanish, and " barilla," the name under which it is known, was given to all vegetable sodas ; even the artificial soda was first known in England as "British ALKALIES. 175 barilla." Barilla is also brought into commerce as Alicante, Carthagena, and Malaga soda. It forms a hard and compact mass of a dark ash or gray-blue color, and contains from 25 to 30 per cent, of sodium carbonate. It is hard and difficult to pul- verize and has a sharp alkaline taste. It is obtained from plants specially cultivated for the purpose. Alicante soda is divided into three varieties : Sonde douce, melangee, and bourde. The first forms a well-fused ash-like mass with 20 to 25 per cent, of sodium carbonate ; the second, a black- ish, blistered mass with a sharp fracture ; while the third is a poorer quality mixed with particles of coal and containing much common salt and earthy constituents. In Southern France two varieties of vegetable soda are pro- duced, the "salicor," or Narbonne soda, with 14 to 15 per cent, of carbonate, in the region around Narbonne, from Salicornia annua ; and " blanquette," or " soude d'aigues-mortes," with only 4 to 10 per cent, of carbonate, from several other varieties of plants. Vegetable soda, being only caked vegetable ash not purified by lixiviation, contains all the inorganic constituents of the plants. Hence, when treated with water, there always remains a consider- able residue of combinations of lime, iron, etc. The portion solu- ble in water contains, besides sodium carbonate (and potassium carbonate), alkaline sulphates and chlorides. At the present time the natural soda has been almost every- where replaced by the artificial product, it being only used in the countries of its production. Artificial soda. — During the last century the soap industry of France had become so extensive that twenty to thirty millions of francs were annually sent to Spain and other countries for veg- etable soda. In 1793, when France, by its war with England, was excluded from intercourse with other nations, and, therefore, dependent on its own resources, the want of potash and soda was much felt in the soap industry. A commission was appointed to examine methods for the fabrication of soda. Of the various processes communicated, the one proposed by Nicolas Leblanc, to manufacture soda from common salt, was considered the only practical one. The industrial process was exposed with such 176 MANUFACTURE OF SOAP AND CANDLES. precision that since that time — nearly a hundred years — very few changes have been made. Leblanc, as previously mentioned, shared the fortune of almost every inventor, so that at the time of his death, in 1806, he was in a state of abject poverty. Leblanc' s method of manufacturing soda consists of heating a mixture of sodium sulphate (Glauber's salt), calcium carbonate, and charcoal, whereby sodium carbonate is formed, with a simul- taneous formation of calcium sulphide, caustic lime, and carbonic oxide. The sodium sulphate is generally prepared from common salt (sodium chloride) by allowing dilute sulphuric acid to act upon the common salt in a suitable furnace at a high temperature ; the result is sodium sulphate and hydrochloric acid : — 2NaCl _!_ H 2 S0 4 = 2HC1 + Na 8 S0 4 Common salt. Sul phuiic acid. Hydrochloric acid. Sodium sulphate. The calcium carbonate is used either in the form of limestone or chalk. Leblanc recommended charcoal ; at the present time hard coal, or sometimes brown coal, is generally used. The fusion of the soda mixture is carried on in reverberatory fur- naces, which generally are of a very simple construction, except the mechanical or rotatory furnaces in use in the larger English factories. The crude soda coming from the furnace consists chiefly of 36 to 40 per cent, of sodium carbonate and varying quantities of calcium sulphide, caustic lime, and calcium carbonate. It also contains small quantities of sodium chloride, sodium sulphate, sodium silicate, various sulphur combinations of the soda with more or less oxygen, etc. In the infancy of the manufacture the crude soda coming from the furnace was directly brought into commerce and bought chiefly by soap-boilers. It was manufac- tured on a large scale in Marseilles, and as late as 1818 exported in this form to England. But as crude soda on storing in the air is constantly changed by chemical conversions at the expense of quality, it has long ago ceased to be an article of commerce, it being only used in very few places in France. To obtain a purer and more durable product the crude soda is subjected to the process of lixiviation. ALKALIES. 177 To obtain a concentrated solution at as little expense as possi- ble, the lixiviation of the crude soda is systematically carried on in Shanks's apparatus. The crude soda lye thus obtained is con- centrated by evaporation and converted into a commercial article by calcination. Evaporation is effected in pans either by bring- ing heat to bear on the surface of the liquid or conveying it to the bottom of the pan. The salt separated during evaporation is gradually removed by perforated ladles and thrown into a hopper, from which the mother-lye runs back into the pan. When the latter is about half empty fresh lye is run in, and in this way the operation is continued for several months until the mother-lye contaminates the separating salt too much. The mother-lye, w T hich contains much caustic soda and sodium sulphide, is frequently worked into caustic soda ; when this is not done, these soda com- binations have to be removed from the lye by a process called "carbonization." This is frequently done by evaporating the lye with an addition of saw-dust and calcining. In some large works the calcined salt is re-dissolved, treated with carbonic acid, and again evaporated. Calcining is effected in a reverbatory furnace, the crystalline carbonate being first drained, which is sometimes performed in centrifugal turbines. By these means a product is obtained con- taining according to circumstances from 90 to 97 per cent, of so- dium carbonate. The soda thus obtained is either ground and then sold, or, for many purposes, again refined. Good calcined soda (second quality) obtained by the described process, should be white but never yellow or reddish ; it is, of course, not as white as prime quality. Frequently it shows a bluish color, which may be due to some ultra-marine or sodium manganate, already formed in the crude soda, but in modern times these are sometimes intentionallv added. A ^rav-color of the soda in- dicates defective carbonization and calcination. Such soda gen- erally contains a considerable quantity of caustic soda and of sulphur combinations. For many purposes ordinary calcined soda is not sufficiently pure. The caustic soda, and especially the content of iron as well as all that remains as an insoluble residue in dissolving second quality soda, exerts in many cases an injurious influence, especially 12 178 MANUFACTURE OF SOAP AND CANDLES. where soda has to be used without previous solution as in the manufacture of glass. For the finest qualities of glass and for some other purposes, a refined soda (white alkali) is therefore de- manded. The required degree of purity can but seldom be at- tained by evaporating, draining, etc., of the crude lye, and re- course must therefore be had to calcining and re-dissolving the crude salt. Theoretically refining is a very simple operation, consisting simply of clarifying, evaporating, and calcining. Practically it, however, requires great care and attention to ob- tain a product answering all commercial demands. The greater portion of soda is ground before it is brought into commerce. This not only gives a better appearance to the pro- duct, but the cost of grinding is much less than the extra ex- pense of packing un ground soda which takes up about 50 per cent, more of space. A plan for the direct conversion of common salt into soda has long been sought. The ammonia process proposed for this pur- pose is based upon the fact that by mixing a concentrated solu- tion of ammonium bicarbonate with a saturated solution of com- mon salt, sodium bicarbonate will be deposited while sal-am- moniac remains in solution : — 2NaCl + NH 4 HC0 3 = 2NH 4 CL + NaHC0 3 Common Ammonium Sal-ammoniac. Sodium salt. bicarbonate. bicarbonate. By gradually heating the sodium bicarbonate to redness it loses half of its carbonic acid which can be again utilized, while by treating it with lime or magnesia the ammonia can be re- gained. The entire reaction is so simple and so readily carried out in the laboratory that it is no wonder many attempts have been made to utilize the process for industrial purposes. H. G. Dyar and J. Hemming, of England, were the first to take out a patent for this purpose ; the merit, however, of practically carry- ing out the process belongs to T. Schloesing and E. Kolland, who, in 1855, established a factory at Puteaux, near Paris, which, how- ever, was abandoned in a short time. The credit of the further development of the ammonia process belongs chiefly to E. "Solvay, of Couillet, near Charlevoix, Belgium. Solvay^s process is as follows : A concentrated solution of com- ALKALIES. 179 mon salt is first saturated with ammonia and then with carbonic acid. Ammonium bicarbonate is formed, which, with the com- mon salt, is converted into sodium bicarbonate and sal-ammoniac. The sodium bicarbonate is decomposed, by heating, into sodium carbonate and carbonic acid, the latter being again used for the formation of ammonium bicarbonate. From the solution of sal- ammoniac obtained in the commencement of the process, the ammonia is recovered by heating with lime. The process is, therefore, a continuous one, requiring, independent of the loss of ammonia, only an introduction of common salt and of a portion of the carbonic acid, while soda alone is taken out. Only the lime required for the regeneration of the ammonia and the chlo- ride from the common salt are lost. The entire process seems very simple ; it requires, however, very complicated apparatus and a considerable outlay for the establishment of a factory. Soda prepared by the ammonia process is very pure, being absolutely free from caustic soda, sulphur combinations, and iron, It can be obtained without difficulty so as to show 98 to 99 per cent. Another variety of soda which deserves mention is that ob- tained from cryolite, a mineral occurring in Greenland. It con- sists of fluoride of sodium and aluminium, and when perfectly pure contains in 100 parts 13.07 aluminium, 33.35 sodium, and 53.58 fluor. The soda is obtained by heating the pulverized mineral, mixed with 1J times its quantity of chalk, to redness, whereby, under the development of carbonic acid, calcium fluoride and sodium aluminate are formed. The calcined mass is lixi- viated ; the calcium fluoride remains behind, while the sodium aluminate passes into solution. By the introduction of carbonic acid, generated by the combustion of coal, into the sodium alumi- nate, it is converted into alumina, which separates, and into sodium carbonate, which remains in solution. The soda solution is concentrated by evaporation, the larger portion of the soda crystallizing out in from eight to ten days. The separated alumina is not pure, but a mixture of 45 per cent, of alumina, 20 per cent, of sodium bicarbonate, and 35 per cent, of water; it is generally further worked for alum. 180 MANUFACTURE OF SOAP AND CANDLES. Crystallized soda. — Notwithstanding the great quantity of water (crystallized soda consists of 37.08 parts of sodium carbon- ate and 62.92 parts of water), for which freight has to be paid, and the further disadvantage that an equal weight of crystallized soda requires far more packing space than calcined soda, it is manufactured on a large scale, not only in soda factories, but in special establishments, chiefly in Northern France and Holland, which buy calcined soda and convert it into crystallized soda. The principal reason why this product can bear the increased cost of freight, packing, and manufacture is due to its purity, of which crystallization is an external evidence. Large quantities of it are used in many branches of industry, even where the calcined arti- cle would answer the purpose as well and be cheaper. Its prin- cipal consumption is, however, for household purposes, cleansing, washing, etc. For this it is of great importance that it be abso- lutely free from caustic soda and other combinations attacking the skin. It has the further advantage of being broken up and handled with greater ease than the pulverulent calcined soda, which by exposure to the air cakes together ; besides, it is readily soluble in water, while a large portion of the calcined soda re- mains undissolved as a hard lump in the wash-tub, and pieces of it become mixed with the clothes to their injury. Though for most purposes a slightly yellow color derived from organic substances w T ould do no harm, an article as colorless as possible is demanded in commerce, and this is but right, it being a guarantee to the consumers that the article is entirely free from iron, etc. Notwithstanding innumerable attempts, it has never yet been found possible to produce salable crystallized soda directly from the crude lyes of soda factories. It is almost ex- clusively manufactured by dissolving calcined soda with the assistance of heat and allowing the solution to cool in iron vessels. The calcined soda used should be as free as possible from caustic soda and the lower groups of oxidation of sulphur, as well as from sodium sulphide. Coloration due to ferric oxide does no injury, since it. remains behind in solution. The calcined soda is dissolved so that the solution shows 30° to 40° B., the solution is allowed to settle, and the clear lye is run into the crystallizing vessels. The latter are filled nearly to the edge and several ALKALIES. 181 pieces of hoop-iron are laid crosswise over it so as to touch the surface of the liquid. Crystallization begins on this iron frame, a complete incrustation of crystals being soon formed which grows down into the liquid and frequently attains a length of over twelve inches. This incrustation yields the best quality of crys- tals, those formed on the sides of the vessels, which have to be cut off with a chisel, being less beautiful, while those formed on the bottom are the poorest quality. To avoid a contamination with iron, the vessels have to be kept bright and free from rust ; sometimes they are painted. The mother-lyes always retain some sodium carbonate, and the more the higher the temperature during crystallization. They contain besides all the caustic soda and the greater portion of the sodium chloride and sulphate. These mother-lyes are evaporated in pans to the consistency of paste and then calcined in a rever- beratory furnace. They yield a very white soda salt of a weak degree, containing only from 40 to 50 per cent, of pure soda. Crystallized soda is frequently adulterated with Glauber's salt, and generally for consumers, such as wash-women, to whom the latter is of absolutely no value. According to J. H. Swindells, the manufacture of such spurious crystallized soda is carried on on a large scale, the product being brought into the market as best Scotch soda. The adulteration is, however, readily detected. Dissolve some of the soda, acidulate the solution with hydro- chloric acid, and compound with solution of barium chloride ; in the presence of Glauber's salt a thick white precipitate is formed. Caustic soda. — Under this name is understood a product con- sisting chiefly or entirely of sodium hydrate. There is also found in commerce a soda lye which is shipped in glass balloons. For many evident reasons the trade in this article is not very exten- sive, consumers generally preferring to prepare it themselves from calcined soda and lime. The manufacture of solid caustic soda was originally introduced into England, in 1844, by a German named Weissenfeld. The actual commencement of its manufac- ture on a large scale dates, however, from about 1853, when William Gossage took out a patent, which, besides other improve- ments in the manufacture of soda, included the gaining of caustic soda from soda lyes by concentration and without the use of lime. 182 MANUFACTURE OF SOAP AND CANDLES. The caustic soda first brought into commerce was colored blue, green, yellow, red, etc., it being only in 1860 that Ralston suc- ceeded in producing the white product by heating the caustic soda to a higher temperature than was formerly customary, i. e., to a temperature at which the iron separates as oxide and the clear caustic soda is left standing over it. For the manufacture of caustic soda calcined soda was formerly dissolved and made caustic by lime. At the present time this method being too dear has been almost entirely abandoned, the crude lye gained by lixiviating the crude soda being now treated with lime. The lye before being made caustic must be thoroughly clarified and a good quality of lime has to be used. Dilute the crude lye with water to from 11° to 13° B., as more concentrated solutions cannot be made completely caustic. It is safe to go as high as 13° B., and in doing so less water has to be evaporated. Many factories even go as high as 15° B., whereby only about 92 per cent, of the soda is made caustic, but a saving in coal is effected. The lye is brought to ebullition and the lime added with constant stirring. It is best to use quick lime, as it is im- mediately slaked on being added, and the heat developed thereby saves steam. A skilled workman can judge from the manner of boiling, the color of the liquid, and other indications when a sufficient quantity of lime has been added ; this can, however, also be tested by filtering a sample and adding some sulphuric or hydrochloric acid, whereby no effervescence must take place. The entire charge can then be either drawn off into a settling vessel, or it is allowed to settle in the pan itself, which requires about half an hour. The clear lye is then gradually drawn off and pumped into vessels for complete clarification. Generally a second operation is carried on in the pan without removing the lime-slime. The pan is again charged with crude lye and water, the contents brought to ebullition and made caustic, somewhat less lime being required than for the first charge, since some caustic lime remains in the slime. After the clear lime is drawn off, the lime-slime is stirred with pure water to a thin paste and brought upon especially constructed filters. The filtrate serves for the dilution of the crude lye. The remaining lime-slime is generally used as a substitute for a portion of the quick lime for ALKALIES. 183 a fresh soda mixture, it being well adapted for this purpose, as it is in a finely divided state and, besides the soda contained in it, is thus utilized. The caustic soda obtained in this manner is still in a state of great dilution. Its concentration, which is an important task, as it is necessary to save as much fuel as possible, is effected in cast- iron or wrought-iron pans. For the production of a 60 per cent, caustic soda, the lye is evaporated until it shows 37° to 38° B., and a temperature of 281° F. The fire is then withdrawn and the contents of the pan allowed to rest for clarification and the deposit of the salts. For the production of 70 per cent, caustic soda the lye is concentrated in English factories to about 42° to 44° B. After allowing the contents of the pan to settle, the clear lye is drawn off into clarifying vessels and the salt brought by a perforated ladle into a filter to be returned after draining off to the soda furnace. The clear lye is brought into an iron kettle, generally large enough to hold ten tons of caustic soda, and the fire is started. With a temperature of from 399° to 420° F., a reddish or sometimes a blackish froth forms on the surface. In most factories manufacturing 60 per cent, caustic soda this froth is removed ; it is, however, absolutely necessary to remove it for 70 per cent, caustic soda. For caustic soda of less concentration it is advisable to withdraw the fire when the temperature has reached 320° F., so that, by allowing the contents of the pan to clarify once more, more salts may separate and a purer lye be obtained. The boiling is then continued. When the fluid has reached a temperature of 356° F., it already contains 53 per cent, of sodium oxide (nearly equal to 70 per cent, of caustic soda) and congeals completely on cooling. It is very dark and of a syrupy consistency, and shows a great tendency to boil over. This is prevented by the workman beating the surface of the fluid in a peculiar manner with a shovel, which separates the froth. When the mass has reached a temperature of 401° F. ebullition ceases almost entirely and but little vapor escapes, though the mass still contains nearly 20 per cent, of water. At about 460° F. the mass contains almost exactly 60 per cent, of sodium oxide = 77 J per cent, caustic soda. At this stage the contents of the pan show scarcely any motion, 184 MANUFACTURE OF SOAP AND CANDLES. there being but a slight ebullition on the edge of the pan. The vapor, which is still developed, carries along small quantities of caustic soda, which produce a very disagreeable, stinging sensa- tion upon the skin. The surface of the mass becomes covered with a lustrous coat of graphite, while a reddish separation of salts is formed around the edge of the kettle. An iron lid is now placed upon the kettle and the fire made as strong as possi- ble. When the mass has reached the proper temperature the complete oxidation of the sodium sulphide still present, as well as that of other sulphides and cyanides, is finished either by the addition of sodium nitrate or by blowing in air. A sample is then taken and examined as to its alkalinity. The color of the mass varies from light brown to deep red. The contents of the kettle are now allowed to clarify in the kettle itself, which gene- rally requires eight to twelve hours, a strong fire being kept up during this time. The quality of the product depends on com- plete clarification. The mass is then run into sheet-iron drums ■ if it is not entirely clear and colorless the solid caustic soda will show defects. The sediment in the boiler, which amounts to about 9 to 11 per cent, of the mass, is generally brought into iron boxes and, after cooling, is broken up and again dissolved. The solution is brought to 28° B., allowed to settle, and the clear liquid added to the crude lye to be rendered caustic. The residue, which chiefly consists of ferric oxide, is thrown away. For the production of 76 per cent, caustic soda it is preferable to remove the sodium sulphite from the diluted lyes, instead of waiting to the end of the operation. This is best effected by a suitable metallic oxide. The Greenbank Alkali Works Co., that first introduced caustic soda of a high degree, and furnish at the present time an excellent product, use plumbic oxide (or litharge) for the purpose. Commercial valuation of soda. — The commercial valuation of soda is differently indicated by the three principal countries of its production : in Germany according to per cents, of sodium car- bonate, in England according to per cents, of actual or available soda, and in France according to degrees of Descroizilles founded upon an arbitrary basis. The designation according to German degrees seems to be the most rational one for ordinary soda, but ALKALIES. 185 is a very unfortunate one when applied to caustic soda. The English method, according to per cents, of available soda, is de- cidedly the best. Under available soda is understood everything that acts upon the test acid, because in the manufacture of soap it acts in the same manner as soda. In France these degrees are called Gay-Lussac's degrees ; they are, however, never used in practice. Pure sodium carbonate contains, according to the Eng- lish designation, 58.49 per cent. As sodium oxide is understood as a constituent of the hydrate, it is perfectly correct to apply the same degrees to caustic soda. If an Englishman, therefore, speaks of a soda of 52 per cent., it means that the test acid neu- tralized by the soda corresponds to a quantity of fVo" °^ the weight of sodium oxide used, which may, however, be present as carbonate, silicate, aluminate, hydrate, and even as sulphate. Unfortunately, in practice an error has crept into this otherwise rational designation which thus far has only been partially erad- icated. The old incorrect equivalent of sodium of 32 is still used instead of 31, and the test acids have been regulated accordingly. Thus too high a percentage is obtained, which does not correspond to the actual percentage of sodium oxide, the value being made to appear higher by -£j than it actually is. Moreover, there is a further difference between the Tyne and Lancashire manufac- turers, the former basing their valuation on the equivalent of sodium carbonate which they take at 54 instead of 53, the test acid being prepared so that 1 litre of it saturates 54 grammes of pure sodium carbonate. Pure sodium carbonate, with this test " _ n . ,. 32 x 100 . . ■ n acid, therefore, indicates -^ = 59.26 per cent., instead of 58.49 per cent., and hence 0.77 per cent, too much. Every English statement of degree shows, therefore, 1.316 per cent, too much of its total amount ; 50 per cent, of actual sodium oxide show, for instance, 50 + 50 x 0.0136 = 50.66 English degrees, as calculated by the Tyne manufacturers, as well as by the prin- cipal commercial analysts in England. In Liverpool, however, a practice has been gradually established which is not even based upon an erroneous equivalent, but simply intended to deceive the consumer. It is there customary to say : "As the 'old' equiva- lent of the pure sodium carbonate is ■£% larger than the ' new/ 186 MANUFACTURE OF SOAP AND CANDLES. all we need to do is to increase our per cent, figures found accord- ing to the actual equivalent by fa in order to obtain the com- mercial valuation ; hence, we call 53 per cent, sodium oxide 54 per cent.' 7 We would, however, remark that certain large Eng- lish firms send out their soda ash according to the real equivalent. The most irrational of all methods of valuation is that accord- ing to degrees of Descroizilles, in general use in France. These degrees indicate how many parts of pure mono-hydrated sul- phuric acid (double oil of vitriol) are neutralized by 100 parts of the soda ash in question. As the equivalents of sodium carbonate and double oil of vitriol are as 53 : 49, 100 parts of pure sodium carbonate require 92.41 parts of double oil of vitriol, and, hence, show as many degrees of Descroizilles. To avoid the tedious calculation of one method of valuation into the other, we give a comparative table which shows the actual per cents, of sodium oxide (Gay-Lussac's degrees), of sodium carbonate (according to German and English degrees), and Descroizilles's degrees. ■ Gay- Lussac's degrees. German degrees. Euglish degrees. Descroi- zilles's degrees. Gay- Lussac's degrees. German degrees. English degrees. 30 51.29 30.39 47.42 54 92.32 54.71 31 53.00 31.41 49.00 55 94.03 55.72 32 54.71 32.42 50.58 56 95.74 56.74 33 56.42 33.43 52.16 57 97.45 57.75 34 58.13 34.44 53.74 58 99.16 58.76 35 59.84 35.46 55.32 59 100.87 59.77 36 61.55 36.47 56.90 60 102.58 60.79 37 63.26 37.48 58.48 61 104.30 61.80 38 64.97 38.50 60.06 62 106.01 62.82 39 66.68 39.51 61.64 63 107.72 63.83 40 68.39 40.52 63.22 64 109.43 64.84 41 70.10 41.54 64.81 65 111.14 65.85 42 71.81 42.55 66.39 66 112.85 66.87 43 73.52 43.57 67.97 67 114.56 67.88 44 75.23 44.58 69.55 68 116.27 68.89 45 76.94 45.59 71.13 69 117.98 69.91 46 78.66 46.60 72.71 70 119.69 70.92 47 80.37 47.62 74.29 71 121.39 71.93 48 82.07 48.63 75.87 72 123.10 72.95 49 83.78 49.64 77.45 73 124.81 73.96 50 85.48 50.66 79.03 74 126.52 74.97 51 87.19 51.67 80.61 75 128.23 75.99 52 88.90 52.68 82.19 76 129.94 77.00 53 90.61 53.70 83.77 77 131.65 78.01 Descroi- zilles's degrees. 85.35 86.93 88.52 90.10 91.68 93.26 94.84 96.42 98.00 99.58 101.16 102.74 103.32 105.90 107.48 109.06 110.64 112.23 113.81 115.39 116.97 118.55 120.13 121.71 ALKALIES. 187 Potash. — Commercial potash forms a mixture of salts, the principal constituent of which is potassium carbonate. When calcined it is a hard but light, porous, granular mass with a white color shading into pearl-gray, yellowish, or bluish. Separate pieces frequently show blue or red stains upon the fracture. The red coloration is due to ferric oxide, the gray to admixed parti- cles of coal, and the blue to the formation of a small quantity of potassium manganate by the action of the alkali upon manganic oxide. Potash has a strong alkaline taste and is inodorous. It readily dissolves in water, a considerable quantity of indissoluble constituents frequently remaining behind. It absorbs moisture from the air, deliquescing thereby. Its solution shows an alka- line reaction. It melts at the beginning of a red heat. Four varieties of potash are found in commerce : 1, from wood ashes ; 2, from the residue of beet-root molasses ; 3, from wool sweat (suint) ; 4, from potassium sulphate according to Leblanc's process. Potash from wood-ashes. — The industrial manufacture of potash from wood-ashes is carried on only in countries where wood is abundant, as in Russia, Illyria, Hungary, and the United States. The process of manufacture is very simple and may be divided into five operations : 1. Incineration of the plants; 2. Lixivia- tion of the ashes ; 3. Evaporation of the lye ; 4. Calcination of the crude potash ; 5. Purification of the potash. Little need be said about the incineration of the plants, the process being not the same in every country. The slower the combustion, however, the more ash is obtained. With a vig- orous combustion not only a considerable portion of the ash is carried off by the draught, but a portion of the alkaline salts evaporates on account of the high temperature. The object of lixiviating, leaching, or washing the ashes, is to separate the soluble salts from the insoluble. The former consist chiefly of potassium carbonate, sulphate, and chloride. It is not indifferent whether leaching is effected with cold or hot water. Potassium carbonate and chloride dissolve readily in cold water, potassium sulphate, however, with difficulty. By leaching, there- fore, with cold water less potash is obtained, but it is richer in 188 MANUFACTURE OF SOAP AND CANDLES. potassium carbonate. But potassium sulphate being also a very valuable salt leaching is generally effected with hot water. Lixiviation is mostly carried on in wooden vats about 3J feet high and 3 J to 5 feet in diameter. They are provided about 4 to 6 inches above the actual bottom with a perforated bottom, in which is inserted a vertical pipe for the escape of air expelled by the water, which otherwise would have to force its way through the ash. To prevent the carrying away of insoluble constituents of the ash, the perforated bottom is covered with a straw mat, or with a layer of straw several inches thick, over which is gene- rally placed a piece of coarse linen. On one side immediately below the perforated bottom the vat is provided with a discharge- cock. The space between the two bottoms becomes gradually filled with fine particles of ash passing through the straw, and must, therefore, from time to time be cleansed. The ash is first moistened with water, then brought in small portions into the vat and rammed down. Lixiviation is carried on in a systematic manner, i. e., several vats are placed together forming what is termed " a battery. 77 The lye obtained is of a brown color, due to organic substances extracted from the incom- pletely carbonized wood by the potassium carbonate. The resi- due from leaching ashes affords a valuable manure. The evaporation of the lyes is mostly conducted in shallow cast-iron kettles. Alongside these kettles are placed sheet-iron pans which are heated by the fire under the kettles and serve for preliminary warming. The kettles and pans being filled a strong fire is started. The evaporated liquid is constantly replaced by fresh lye from the pans. When the lye has acquired a syrupy consistency, the supply of fresh lye from the pans is interrupted and the fire moderated. On the side of the kettle a salt crust separates, which becomes thicker and thicker until all the lye is converted into a dry salt-cake, when firing is entirely discon- tinued. After sufficient cooling the brown, hard salt-cake is broken out by means of a hammer and chisel. This crude pro- duct, containing about six per cent, of water, is known in the trade as crude or lump potash. As this method of boiling down and cutting out the crude potash must evidently cause consider- able damage to the iron pans, the operation is, in some instances, ALKALIES. 189 conducted in a somewhat different manner. The liquid is stirred with iron rakes, and the salt, instead of forming a hard solid mass, is obtained as a granular powder containing upwards of 12 per cent, of water. A peculiar kind of potash, consisting chiefly of caustic potash with varying quantities of potassium carbonate, is produced in this country, and brought into commerce under the name of " Red American Potash" or " stone ash." For its production the crude potash liquor is heated to ebullition, and a quantity of milk of lime added according to the intended degree of causticity. The carbonate of lime formed is allowed to settle, when the clear lye is drawn off and evaporated until no more water escapes. It is finally heated nearly to redness in the evaporating pan itself, or in a special pan of thick cast iron, in order to destroy the or- ganic substances and to melt the potash. The liquid potash is then ladled out with a sheet-iron ladle into cast-iron boxes to congeal to a stone-hard mass permeated with bubbles. The product, after removal from the boxes, is broken up and imme- diately packed into tight barrels. It is always contaminated with ferric oxide and has a dirty red or brown color. The object of calcining the crude potash, which is effected in a reverberatory furnace, is to remove the last particles of water, and specially to destroy the organic substances to which is due the brown color. Potash obtained from wood-ashes is, as previously mentioned, chiefly a mixture of potassium carbonate, sulphate, and chloride. For some applications of potash these three are almost of equal value, as, for instance, for the fabrication of alum ; for most pur- poses, however, the content of potassium carbonate is the valu- able portion. Whether the article is poor or rich in the latter can be recognized by the behavior of potash on exposure to the air in an open vessel. Potassium carbonate is a very deliques- cent salt, absorbing moisture from the air with avidity ; if, there- fore, potash rapidly becomes moist on exposure to air, it is an in- dication of it being rich in potassium carbonate. Potash from the carbonized residue of beet-root molasses. — For many years wood-ash was the only source of potash. But, of late years, the manufacture of potash salts from the residue or 190 MANUFACTURE OF SOAP AND CANDLES. vinasse left after the distillation of fermented beet-root molasses has become a new branch of industry. The residue, in case it contains free acid, is first neutralized by an addition of calcium carbonate. It is then evaporated to dryness and the residue heated until carbonization of the organic substances is effected. The composition of the carbonized residue varies, but may be gleaned from the following approximate analysis : — Potassium carbonate . . . . 30 to 35 per cent. Sodium carbonate . . . . . 18 to 20 " Potassium chloride . . . . 18 to 22 " Potassium" sulphate ■ . . . . . 6 to 8 " Insoluble matter . 28 to 15 " In the insoluble matter are contained coal, calcium carbonate, and phosphate. While the carbonized residue is mostly manufactured in the molasses distilleries it is generally refined in chemical factories. The process is very simple, it being based upon the different proportions of solubility of the various salts. In many factories the carbonized residue was formerly simply lixiviated with water, and the lye thus obtained evaporated to dryness, 100 pounds of carbonized residue yielding by this process 45 to 60 pounds of potash, which showed 50 to 60 alkalimetric degrees. Much of this kind of potash was brought into commerce during the Crimean war, when there was a want of Russian potash, and contributed much to the disfavor with which the article was con- sidered by soap-boilers. In more modern times a separation of the separate salts is generally effected, whereby a potash is obtained containing still 8 to 15 per cent, of sodium carbonate, which, however, can be reduced to 4 per cent, by redissolving and re-evaporating. Potash from wool sweat (suint). — The wool of sheep is saturated with a yellow, fatty substance, the so-called sweat or suint, secreted by the skin of the animal. It consists of a combination of potas- sium with the nitrogenous acid of a special fat,* which is partly in a free state and partly combined with earths to an insoluble * Compare wool fat, p. 123. ALKALIES. 191 soap, and of small quantities of potassium carbonate and acetate, alkaline chlorides, and an odoriferous substance. Its content of sodium is very small. In order to reduce the consumption of fuel to a minimum it is necessary in working suint to obtain as concentrated liquids as possible. For this purpose the wool is pressed into vats and lixiviated with water in such a manner that all the water passes through several lots of wool, and several times through each lot, which is finally washed with fresh water. The solutions are then evaporated to dryness, and the residue heated to a red heat in iron retorts, the result being the formation of carburetted hydro- gen gas and ammonia, which having been eliminated, the gas is used for illuminating purposes. The carbonized residue in the retort contains the alkaline salts which are recovered by lixivia- tion with water. The lye thus obtained contains potassium carbonate, chloride, and sulphate, which are separated from each other by evaporating the solution and subsequent crystallization. Potash from potassium sulphate. — While the previously men- tioned sources of potash are limited, its manufacture from potas- sium sulphate, introduced of late years, promises to become a branch of industry of unlimited extent. Much of the potash salts, which find their way into the English market, are derived from the so-called "Strassfurt salts," produced from the alkaline minerals found in enormous quantities in the valley of the Bode about twenty-five miles southwest of Magdeburg. The manu- facture of potash from potassium sulphate was introduced into Germany, in 1861, by Vorster & Griineberg, of Kalk, near Cologne. The manufacture of potassium chloride is based on the decomposition of carnallite contained in the raw material, in a hot saturated solution, potassium chloride crystallizing out, and magnesium chloride remaining in solution. The hot solution is brought to 36J° B., diluted to 35° B., run into settling tanks, and allowed to crystallize ; these crystals, once refined, are almost pure potassium chloride. The next stages of the process are almost identical with those of the Leblanc soda process, the raw material (potassium sulphate) being obtained either from potas- sium chloride and sulphuric acid by the ordinary sulphate pro- cess, or by decomposing the former with magnesium sulphate or 192 MANUFACTURE OF SOAP AND CANDLES. kieserite. Equal weights of potassium sulphate and finely divided limestone or chalk, together with varying quantities of small coal, are roasted together in a reverberatory furnace, the product being an exceedingly impure potassium carbonate. When the decomposition is complete, the molten mass is raked out, broken up when cool, and lixiviated in tanks. The soluble potassium and soda salts are thereby dissolved out, evaporated, and calcined in a small reverberatory furnace. A carbonate of better quality is produced by following more closely the carbonating operation of the soda process. The liquors from the tanks are evaporated, the potassium chloride and sulphate, which separate out during the concentration, being skimmed off and sawdust is thrown in. The dried salts are then removed to the carbon ator and exposed, at first, to a gentle heat, which is, however, finally urged to redness. By this process the sulphur compounds are oxidized into sulphate, and the caustic potash is converted into carbonate. The chief object of the saw- dust is to keep the mass of salt open. Caustic potash. — This article has been for a number of years brought into commerce by the Greenbank Alkali Works Co. of St. Helens, England. It has, however, been but little used by soap-boilers, since the lyes prej)arecl from it come too high (about 25 per cent, higher than tank lyes) ; it is sometimes used to increase the strength of tank lyes. The chemical factory of Buckau, near Magdeburg, and others, having recently commenced the manufacture of caustic potash, a reduction in the price may be looked for, which may enable the soap-boiler to use the article in the manufacture of soft-soaps. TESTING OF SODA AND POTASH. 193 CHAPTER VII. TESTING OF SODA AND POTASH. The value of the different varieties of soda and potash depends on their content of pure, effective substance, i. e., of alkaline car- bonate or caustic alkali. From the preceding chapter it will be readily understood that the quantity of effective substance varies very much in the alkalies found in commerce, and that the value of a particular kind of soda or potash can, therefore, be ascer- tained only by determining its content of pure alkali. For the determination of the value of calcined or crystallized soda, it is sufficient to ascertain the sodium carbonate by the alka- limetric method. It is, however, different with caustic soda, where it is above all required to know how much caustic soda it contains. By directly testing caustic soda by the alkalimetric method an erroneous result is obtained, since the sodium carbon- ate contained in it is also determined as caustic soda. To avoid this error the sodium carbonate has to be separated previously to titration, which is readily effected by means of barium chloride. By adding to caustic soda solution barium chloride solution a white precipitate of barium carbonate or sulphate is formed in the presence of sodium carbonate or sulphate, while no effect what- ever is produced upon the caustic soda. For the examination of soda in this manner, dissolve a weighed quantity of it in hot water and add barium chloride solution until no more precipitate is formed. When all the precipitate has settled on the bottom, filter and rinse with hot water until the water running from the funnel shows no alkaline reaction. The caustic soda in the fil- trate is then determined by the alkalimetric method. "With potash a correct result is never obtained by a mere alka- limetric determination, since the sodium carbonate, which is never wanting even in the best potash, is then also calculated as potas- 13 194 MANUFACTURE OF SOAP AND CANDLES. sium carbonate. The error resulting in this manner is the more serious as sodium carbonate has a lower atomic weight than potassium carbonate and consequently requires a larger quantity of acid for saturation. If, therefore, with a potash containing soda, we calculate the found alkalimetric degrees as potassium carbonate, we obtain a larger sum total than the quantity of the two alkaline carbonates together amounts to. A potash, for in- stance, which contains 85 per cent, potassium carbonate and 5 per cent, sodium carbonate shows an alkalimetric content of 91.62 per cent., and a potash with 85 per cent, potassium car- bonate and 8.6 per cent, sodium carbonate, one of 96.22 per cent. A thorough analysis is, therefore, required for the determination of the value of potash, and as this requires considerable experi- ence in such work, it is best to employ a skilled chemist. Alkalimetry. — The testing of soda and potash by the alkali- metric method is such a simple process that it can be readily learned without much preliminary knowledge of chemistry. To make the processes taking place in the execution of the test clear to persons without chemical knowledge it will be necessary to mention a few chemical laws. It is a fact determined by innumerable experiments and con- firmed by daily experience, that by two bodies acting upon each other, a third body, or, as it is called, a chemical compound, is formed which exhibits properties entirely different from those of either of its constituents, and the proportions of weight of these constituents which form that particular compound admit of no variation whatever. By long-continued trituration, for instance, of mercury and sulphur, cinnabar is formed, the two bodies, how- ever, combining only in the proportion of 200 parts by weight of mercury and 32 parts by weight of sulphur. Every excess of mercury or sulphur above this proportion fails to form cinna- bar, the excess of mercury or sulphur, as the case may be, remain- ing behind. In the same manner 23 parts by weight of sodium combine with 35.5 parts by weight of chlorine to common salt. The numbers which express the proportions of weight in which bodies form combinations are called atomic weights. By careful experiments chemists have determined the atomic weight of every body and have found that, for instance, the atomic weight of TESTING OF SODA AND POTASH. 195 sodium is 23, that of potassium 39, that of calcium 40, that of sulphur 32, that of chlorine 35.5, that of carbon 12, that of oxy- gen 16, that of hydrogen 1, etc. If, therefore, two or three of the mentioned bodies form a combination, it is done in the pro- portions of the numbers given. To this must, however, be added that the bodies may also combine in the proportions of twice, three times, or four times the above numbers. Water, for in- stance, is a combination consisting of 2 x 1 part by weight of hydrogen and 16 parts by weight of oxygen. Soda or sodium carbonate consists of three bodies, viz., 2 x 23 parts by weight of sodium, 12 parts by weight of carbon, and 3 X 16 parts of oxygen. Hence the chemical law : When two or more bodies combine chemically, it is done in the proportion of the atomic weights or their simple multiples. This most important of all chemical laws finds application in the determination of the constituents of various bodies. The branch of chemistry which occupies itself with the determination of the constituents of bodies is called " chemical analysis." There are two methods of determining the quantity of a body in a given substance, viz., gravimetric analysis, or analysis by weight, and volumetric analysis, or analysis by measure or process of titration (analysis by means of standard solutions). By the first method the substance to be examined is reduced to forms or combinations which are most accurately known as regards the proportions of the quantity of their constituents and admit at the same time of a sharp determination of weight. By volumetric analysis, on the other hand, the quantity of a body is found by reducing it from a determined condition into another also determined condi- tion, by the assistance of a liquid of known effective value and under conditions allowing of a plain recognition of the termina- tion of the reduction. In alkalimetry this final point is recognized by a change of color. For volumetric determinations a few implements are required which shall be briefly described as follows : — For the preparation of the test liquids or normal solutions re- quired for volumetric analysis, serves a flask, Fig. 21, which, up to a mark on the neck, holds exactly 1 liter or 1000 cubic centi- metres, and can be closed with a glass stopper. There are also J 96 MANUFACTURE OF SOAP AND CANDLES. flasks of the same shape with a capacity of 500, 200, and 100 cubic centimetres. For measuring off small quantities of liquids Fig. 21. Fig. 22. \20CC serve a burette and pipette, the latter a glass tube of the form as shown in Fig. 22. It is filled by dipping the lower end into the liquid and sucking on the upper with the mouth until the liquid has ascended nearly to the top. The upper end is then quickly closed with the index finger of the right hand. By slightly lifting the finger, the liquid is then allowed to flow off by drops until its level has reached a mark above the convex expansion, when it will contain exactly the number of cubic centi- metres indicated opposite to the mark. There are pipettes of 50, 20, 10, 5, and 1 cubic centimetres capacity. The burette is a cylindrical glass tube open on the top, gradu- ated, commencing from the top, into whole, one-tenth and one- TESTING OF SODA AND POTASH. 197 fifth cubic centimetres. The lower end of the tube is drawn out to a somewhat distended point so as to allow a rubber tube to be drawn over it and securely fastened. In the lower end a glass tube drawn out to a fine point is inserted. The rubber tube is compressed in the centre by a clip or compression stop-cock, ¥\■-.■ ..-.■■. , .■.-■."..•■.'. -. -: , ■:>»«)> \\\\W ■ •- ■■■...■.v,v\\-,.-.\. .■„>-. .'*v LJLJI , -..-.■■■ : I =! maaaaijaaa ^^i^x^^M^^^ x-t* 1 a .-__ is^^ General Plan of a Soap Factory Working with an Open Fire. A, soap-kettle; B, furnace ; C, grate ; D, principal chimney; E, ash-pit; F, oil reservoir; O, masonry vats for waste lyes; IT, cellar; J, lixiviating vessels; K, stairs ; L, frames ; M, store-rooms for crude soda ; iV~, pulverizing trough, draught equal to one-fourth of its total surface. Experience has shown these proportions to be the best to assure a complete com- bustion of the fuel. Into the chimney D all the products of combustion are dis- charged. The higher the chimney the better the draft. Its inside diameter must always be proportioned to the total opening of the flues of the furnace. To hasten or slacken the combustion in the furnaces the chimney is provided with a register. The object of the ash-pit E is to convey air between the bars of the grate and to serve as a receptacle for the ashes. Its dimen- sions vary, but it is generally as wide as the grate. A pump is placed in each of the cisterns G to raise the waste 280 MANUFACTURE OF SOAP AND CANDLES. lye they contain into a large masonry or sheet-iron vat placed on the first floor. The store-room M contains the raw materials for the prepara- tion of lyes. The materials are pulverized and mixed with lime in the trough N. 2. With the use of steam.— The application of steam to the fabrication of soaps has become nearly general. This system presents many advantages over heating by an open fire. Fig. 71 shows a general plan of a factory in which all the kettles are heated by steam. The steam-boiler A is placed over an ordinary fireplace with cast-iron grate ; the products of combustion escape through the chimney B. From the dome of the boiler the steam is discharged through the pipe C and conducted to the kettles I), which have the ordinary shape, only at the bottom there is a horizontal worm in which steam continually circulates during the boiling of the soap. Each worm is provided with a waste-pipe L, which traverses the bottom of the kettle to discharge the water of condensation. Fig. 71. General Plan of a Soap-Factory, with the Use of Steam. A, steam-boiler ; B, chimney ; C, steam-pipe ; />, soap-kettle ; E, discharge-pipe ; F, masonry cistern ; G, lye reservoir ; H, frames ; J, cutting table ; K, drying- room ; L, discharge-pipe for water of condensation ; M, soap-press. The above-mentioned dome of the boiler is necessary to pre- vent the boiling water from entering the pipe and thence passing into the coil. MACHINES AND UTENSILS. 281 The pipes E conduct the waste lye into the masonry cisterns F. To render the kettles more solid and prevent the loss of heat, the foundation of the kettles is made of brick and cement. The other arrangements are made clear by the letters in the illustra- tion. The lye to be used is in the reservoir G ; the finished soap is brought into the frames H, and after sufficient cooling upon » the cutting table J, where it is divided into bars and cakes which are dried in the drying chamber K. The bars or cakes are finally stamped in the press M. 3. Ground-plan of a soap-faetory y with the use of superheated steam (Fig. 72).— The factory is located in a rectangular building, the basement of which is divided into two compartments, the Fi£„ 72. ' , ' = 1010 (3 X 306) 918 parts by weight 92 parts by weight 1 molecule fat or oil = 3 molecules potassium hydroxide = * , ' and ' ■-, ' — 1028 860 parts by weight (3 X 56) 168 parts by weight Give after saponification — ■ 3 molecules of sodium stearate, palmitate, and oleate = 1 molecule glycerin = > , < and * , ' = 1028 936 parts by weight 92 parts by weight 1 molecule palmitin = 3 molecules water » , and > r-- ' = 860 806 parts by weight (3 X 18) 54 parts by weight Yield after decomposition — ■ 3 molecules palmitic acid — 1 molecule glycerin = « , < and « ■— y— ' = 860 (3 X 256) 768 parts by weight 92 parts by weight The triglycerides contain — Stearin . . . 95.35 p. c, remnant of stearic acid, C ]8 H 35 1 ^ 4.65 " " glycerin, C 3 H 5 '" . 94.66 p. c, remnant of palmitic acid C 16 H 31 "I ~ 5.34 " « glycerin, C 3 H 5 "' . 95.30 p. c, remnant of oleic acid, C 18 H 33 ) ~ 4.70 " " glycerin, C 3 H 5 '" Oil or fat . . 95.23 p. c, remnant of fatty acid 4.77 " " glycerin, C 3 H 5 '" Now, in the saponification with water, these different remnants divide themselves in the remnants of the water, Palmitin Olein } 9 o o H ") ^ H atom of hydrogen H J " HO atom of hydroxide, FABRICATION OF SOAPS. 297 or in the remnants of the modified waters of the lyes, Na lo = Na atom of sodium HO atom :>f sodium ^ 1 o ^ a ^ om °f potassium of hydroxide H J ' HO atom of hydroxide, in snch a manner that the atom of hydrogen, potassium, or sodium combines with the remnant of the acid, and the atom of hydroxide with the remnant of glycerin = glyceryl C 3 H 5 r// , so that the original quantity of fat is augmented by the quantity of alkali. The remnants of acids of the various triglycerides become augmented by — Stearin Palmitin Olein Oil or fat And the remnants of glycerin from Hydrogen. Sodium. Potassium. 0.30 p. c. 8.02 p. C. 13.12 p. c. 0.36 " 8.54 " 14.47 " 0.32 " 7.79 " 13.22 " 0.34 " 7.91 " 13.42 " i from — in, Pal mitin, Olein, Oil or fat, By hydroxide 5.68 p. c. 6.08 p. c. 5.69 p. c. 5.93 p. c. Hence 100 parts of the triglycerides give, after saponification with water, sodium hydroxide or potassium hydroxide — Per cent. Hydrogen stearate 95.73 Glycerin . . . 10.33 106.06 Hydrogen palmitate 95.02 Glycerin 11.42 106.44 Hydrogen oleate 95.63 Glycerin • • . 10.39 106.02 Hydrogen sebate . 95.57 Glycerin . 10.70 Per cent. Per cent Sodium stearate . 103.37 Potassium stearate 10S.47 Glycerin . . 10.33 Glycerin . . 10.33 113 70 11S.S0 Sodium palmitate . 103.20 Potassium palmitate 109.13 Glycerin . . 11.42 Glycerin . 11.42 114.62 120.55 Sodium oleate . 103.09 Potassium oleate . 108.52 Glycerin . . 10.39 Glycerin . . 10.39 113.48 118.91 Sodium sebate . 103.14 Potassium sebate . 108.65 Glycerin . . 10.70 Glycerin . 10.70 106.27 113.84 119.35 The pure dry combinations therefore contain- Sodium oxide. Acid. P. stassium oxide. Acid. Per cent. Per cent. Per cent. Per cent. Stearate . 10.13 89.87 1 14.59 85.41 1 Palmitate . Oleate . 10.84 . 10.19 89.16 [ 89.81 M O O o 15.56 14.33 84.44 1 85.67 j" — c © Sehate . . 10.80 S9.20 j 15.50 84.50 J _ 298 MANUFACTURE OF SOAP AND CANDLES. If saponification is effected, as in the manufacture of candles, by means of lime (calcium hydroxide), 2 molecules of triglyceride enter into decomposition with 3 molecules of calcium hydroxide. 2 (™,}0 S ) + 8°£}o = ™>f}o 2 = &C}0, 2 molecules stearin. 3 molecules Calcium stearate. 2 molecules - calcium glycerin, hydroxide. 100 parts of triglyceride yield— Calcium stearate . . 104.81 p. c. Calcium palmitate 106.07 p. c. Glycerin .... 10.33 " Glycerin .... 11.42 " 115.14 " 117.49 " Calcium oleate . . 104.85 p. c. Calcium sebate . . 105.62 p. c. Glycerin . . . . 10.39 " Glycerin . . . . 10.70 " 115.24 " 116.32 " There are contained in the— Calcium oxide. Acid. Stearate .... 9.00 p. c. 91.00 p. c. ] Palmitate .... 9.19 " 90.81 " © Oleate .... 9.03 " ■ 90.97 " [ o Sebate .... 9.12 " 90.88 " Some more Modern Methods for the Manufacture of Soap. Saponification by sulphuretted alkalies. — Pelouze has shown that the sulphuretted alkalies, used in the same manner as caustic alkalies, possess the property of saponifying fats. At an ordinary temperature saponification takes place in five to ten days, but immediately with the aid of heat. In the latter case sulphide of hydrogen escapes and 1 equivalent of sodium sulphide yields the same quantity of soap as 1 equivalent of anhydrous soda. In regard to this method of saponification, Dullo remarks that though saponification is quickly and completely effected, he can- not confirm the statement that the disagreeable odor can be removed, except Pelouze possesses a means not published by him. Even when carefully avoiding an excess of sodium sul- phide and expelling the sulphide of hydrogen by continued heat- ing, a disagreeable smell remained behind which could not be removed. FABRICATION OF SOAPS. 299 J. Laurent raises the following objection to Pelouze's method, which deserves attention. Two factories in Marseilles manufac- ture daily 44,000 pounds of soap, and if they should adopt this new method, 500 cubic metres (17658.29 cubic feet) of hydrogen sulphide would be daily developed, the injurious influence of which upon the health of the workmen and the hygienic condi- tion of Marseilles would be incalculable. Direct saponification of oil fruits. — Liebreich has patented a process for the direct saponification of copra.* The copra is comminuted, then saponified with caustic soda lye, and the soap paste separated from the cellulose by means of a centrifugal ma- chine. By salting out the paste a grain-soap is obtained which is so hard that it cannot be cut by any of the usual cutting machines. Soaps made of cocoanut-oil are difficult to salt out, and when finally separated by the use of too much salt, inclose a consider- able quantity of the latter. Soaps formerly prepared, according to Liebreich's process, by the Manufactory of Chemical Products at Charlottenburg, from pure copra or from copra and some olein, showed the above defect of containing a considerable quantity of salt, and made the hands rough. G. Heine, of Charlottenburg, prepares at present, according to Liebreich's process, from copra and a considerable quantity of lard, a stock-soap for the manu- facture of fine toilet-soaps, which does not exhibit the above defect, his toilet-soaps being remarkably mild and agreeable in washing. Liebreich claims as an advantage of his process that it is the only sure method by which a neutral soap can be technically ob- tained. Why this should be the case we cannot comprehend, and are of the opinion that with the usual methods of salting out and grinding a neutral soap can just as surely be prepared. Normal soaps. — Kluge & Co., of Magdeburg, add to the fitted soaps bicarbonates in order to convert any free caustic alkali present into carbonate. The soaps which Dr. Deite had occasion to examine were mild and yielded a good lather ; they showed no reaction with curcuma tincture nor with solution of sublimate, which is due to the fact that sodium bicarbonate does not brown curcuma tincture nor redden solution of sublimate. * The pulp of the cocoanut. 300 MANUFACTURE OF SOAP AND CANDLES. CHAPTER XII. HARD SOAPS. I. Curd or Grain-Soaps. a. Curd m~ Grain-Soaps upon Bub-Lye. The boiling of curd-soap upon sub-lye may be divided into three principal operations : The preparatory boiling or pasting, the salting out or separation, and the clear boiling or coction. The object of the first operation is the saponification of the fat, that of the second the separation of the soap from the glycerin and the superfluous water, and that of the third the removal of particles of froth due to incomplete saponification and deposited between the separated curd-soap. Old German curd-soap. — Prior to the introduction of artificial soda, wood-ashes were extensively used for making household soaps, and for hard soaps it was customary to salt out with com- mon salt, either directly or in solution. Where wood is burnt as fuel, and wood-ashes abound and are cheap, or where potash can be procured economically, this process may possess interest and be of useful application, although at present in commercial cen- tres this class of soaps is rarely made. Yet it is necessary, for the reasons stated, to give a description of the process. The preparation of lye from wood-ashes or potash has been given on page 228. To convert 1100 pounds of tallow into curd-soap about 138 bushels of wood-ashes have to be lixiviated, but at present potash lyes are generally used. For the above quantity of tallow, 440 pounds of lye of 10° B. = 1.07 specific gravity = 7.7 per cent, of potassium oxide, are brought into the kettle, and after warm- ing, the tallow is added. To within a short time of the com- mencement of ebullition a strong fire is maintained, but it is then HARD SOAPS. 301 moderated and kept so for five hours. The melted tallow is at once converted into a milky mixture, and as long as lye and fat have not formed a homogeneous combination, the mass boils turbulently in the kettle, without, however, rising. When the mass has been brought to a state of homogeneous mixture, called the "close state" as contradistinguished from the condition in which the soap is granulated and separated from the liquids of the kettle, about 1100 pounds of lye of 16° to 18° B. = 1.125 to 1.142 specific gravity = 12.40 to 13.90 per cent, potassium oxide, are added in four to five portions at short intervals. The boiling now becomes dense and languid and the mass appears of a yellowish-brown color and runs off the spatula in cohesive, long, translucent strings. The soap boils to a paste, and during this process it is necessary to examine whether complete saponifi- cation has taken place and there is a correct proportion of alkali . to fatty acids. If some of the soap be dropped upon a glass and this sample remains clear for some time, becoming turbid only on cooling, the paste is of the right quality ; if, however, the sample becomes turbid in a short time, such turbidity is due either to non-saponified fat distributed in small particles in the paste, or to an excess of lye effecting a separation of solid soap. Non-saponified fat is present if a gray border appears immedi- ately on the edge of the sample, while in the presence of an excess of alkali the sample becomes quickly coated with a whitish film. This defect is readily overcome by an .addition of lye or tallow. When the paste is sufficiently clear, and a sample brought in contact with the tongue causes a slight burning sensation, or shows, as it is technically termed, a slight " touch" it is vigor- ously boiled in order to deprive it of a portion of the superfluous water, until it runs in threads from the spatula, which is termed " spinning of the soap." As soon as this moment arrives, the separation of the soap from its aqueous solution by means of common salt is commenced, which at the same time effects the transformation of the potash soap into soda soap, the latter pro- cess taking place by an exchange of the constituents of the com- mon salt with those of the potash soap, whereby soda soap and potassium chloride are formed. The salt is added gradually and in small portions, and after 302 MANUFACTURE OF SOAP AND CANDLES. each addition the paste is allowed to boil for a short time in order to enable the operator to watch the full effect of the salt, which does not show itself at once. The first addition of salt effects, as a rule, a liquefaction of the paste. After further additions, the soap coagulates and finally comes as a thick mass to the surface. The separation is due to the soap being insoluble in salt solution and the salt withdrawing water from the soap. The fluid sepa- rated from the soap, which is called " sub-lye" or u spent lye," contains, besides the common salt added, the potassium chloride formed by the decomposition and the glycerin formed by the saponification. Great attention was formerly paid to the operation of salting out, since with an insufficient addition of common salt a portion of the soap remains dissolved in the sub-lye, and with too much salt the soap separates too quickly, so that there is danger of the forming of small lumps which combine with difficulty and hence absorb sub-lye. Soap properly salted out must, when taken hot upon the spatula, adhere to it in soft flakes, boil into laminae, and a sample, on being pressed with the thumb in the palm of the hand, must not smear, but peel off as a solid, dry chip, or, as it is technically called, " have pressure." When salting out is finished the fire is removed and the settled sub-lye drawn off or pumped out, or the entire contents of the kettle are transferred into the cooling vat and allowed to rest for the sub-lye to settle. A quantity of the weakest lye is then brought into the empty kettle, and the soap, being carefully re- moved from the sub-lye in the cooling vat, is added and dissolved to a clear paste, which is again carefully salted out. But little salt is required for this operation, as it only serves for the ab- sorption of water. The next operation, " clear boiling" of the soap, is now proceeded with. The object of clear boiling is to withdraw the superfluous water from the soap, to saponify the last remnants of fat, and to form the soap into a solid mass free from froth. This operation was generally executed by allowing the soap to boil up high with a quiet, uniform fire, keeping the spatula always ready to prevent boiling over by beating the soap, or, as it is technically called, " checking" or " curbing" the soap. The soap, which was at HARD SOAPS. 303 first not sufficiently separated from the sub-lye, soon seethes up in small bubbles, which is termed " the soap boils tough." With continued boiling, and the kettle half covered with planks, the water now gradually evaporates, the salt lye becoming more and more concentrated, and by withdrawing more water from the soap the latter contracts and becomes more viscid. Large lam- inae form on the surface, and the steam developed on the bottom of the kettle makes so much noise in escaping through the thick- ening soap that in the language of the soap-boiler "the soap talks." The froth, now full of large bubbles, subsides gradually, the soap forms a uniform mass, and no more water being with- drawn from it, clear boiling is finished. On repeating the test with the thumb the soap can be rubbed to a dry, flexible chip. After removing the fire, the soap is allowed to rest a few hours for the sub-lye to settle, and then brought into the frame. In the thickly-fluid soap thus brought into the frame, mottling is readily produced by adhering impurities. As mottled curd-soap was formerly considered especially good, bole elutriated in lye, pyrolusite, etc., was frequently mixed with the soap before bring- ing it into the frame, in order to make the mottling more pro- nounced. For smooth soap the thick grain was, however, ground with hot water or weak lye, which renders the soap more liquid, and the adhering impurities pass, on account of their specific gravity, into the sub-lye. The soap absorbing some water by this manipulation, the yield is somewhat increased. One hundred pounds of tallow give about 150 pounds of ungrouncl curd-soap, while by grinding the yield may be brought to 156 pounds. Curd-soaps prepared with potash lye are more delicate and softer than those made directly with soda lye, but they are far more expensive, potash being not only worth twice as much as soda with the same percentage of available substance, but a larger quantity is also required. Suppose both substances were chemi- cally pure, 100 pounds of tallow would require for saponification 28 pounds of chemically pure potassium carbonate, or 21 pounds of chemically pure sodium carbonate. Tattoio (curd) soap. — This soap is still much used in the house- hold on account of its great economy in washing, and in the textile industries on account of its great unctuousness and other 304 MANUFACTURE OF SOAP AND CANDLES. good qualities. Besides, tallow is the best raw material for the fabrication of curd-soap and gives the greatest yield, 100 pounds giving from 150 to 160 pounds of soap, according to whether it is more or less ground. The lye required for the fabrication of this soap is prepared from high-graded calcined soda set with 50 to 60 per cent, of lime. It is still better to use caustic soda lyes prepared by dis- solving high-grade caustic soda in water, such lye having the advantage that in salting out no sodium carbonate — of which lyes prepared from calcined soda contain always more or less — passes into the sub-lye, and, as is frequently the case, is lost. Sodium carbonate in lyes, as previously mentioned, does not con- tribute to saponification, and as it is only mechanically mixed with the soap and deposited between the soap-atoms, renders the soap more liquid. In salting out, the sodium carbonate in the paste, not being chemically fixed, is carried into the sub-lye. The preparation of tallow curd-soap by means of soda lye is much the same as that of old German curd-soap, though at the present time the soap is generally boiled upon one water, except where the impurity of the tallow renders a more frequent renewal of the lye necessary. The boiling process is generally carried on as follows : The tallow is brought into the kettle, and as it can only be completely saponified with weak and more caustic lye, tank-lye of 8° to 10° B. (about one-quarter of the entire quantity required for saponification) is added. With a slow fire, the lye and tallow immediately form an emulsion and combine to a paste shortly after the boiling point is reached. This combination, and conse- quent complete fixation of the alkali by the fatty acids, are recog- nized by a sample brought in contact with the tongue, showing no longer a biting, but a more sweetish taste. However, if the mass still shows some sharpness, the complete fixation of the alkali must be effected by continuing the boiling. After a combination of the lye and tallow has been effected, the second portion of lye is added, for which one of 12° to 13° B. will best serve, and the mass thoroughly boiled. The third and fourth portions of lye of 12° to 13° B. are then successively added HARD SOAPS. 305 in the same manner, and the boiling continued until there is a clear thickly fluid mass in the kettle. If it should happen that by having added the lye too quickly a paste is obtained which, though showing sharpness when brought in contact with the tongue, has a turbid and dull appearance, some very weak lye has to be added with slow boiling, when the sharpness will disappear and the paste become clearer. An addition of water or weak lye is also of advantage, when by the use of too strong lye (18° or 20° B.) the combination has been destroyed so that the lye runs separately from the spatula. We would further remark that the use of lyes too low in lime can only be injurious, since they not only combine with difficulty with the tallow, but the large quantity of sodium carbonate always contained in such lyes is liberated by salting out and passes into the sub-lye. The saponification of the tallow may be considered complete when a sample of the paste brought upon a glass plate shows immediately a narrow whitish border (lye-rings) ; remains clear for some time, becomes turbid only on cooling, and when brought in contact with the tongue, gives a perceptible burning sensation (touch). To deprive the paste of a portion of its superfluous water, it is now thoroughly boiled until it runs in cohesive threads from the spatula. It is then separated from its aqueous solution, which is generally effected by means of common salt. For this purpose salt in small portions is added to the soap paste by which it is soon rendered more liquid. The separation of the soap from the sub-lye is then effected by the gradual addition of more salt. This separation is based upon the fact, that the soap is insoluble in strong salt solution, and that the salt withdraws water from the soap. This salting out is best effected by keeping the soap at a gentle ebullition. Soap correctly salted out should boil into laminae, appear in white flakes upon the spatula, and stand the test of pressure described on p. 302. The sub-lye should run off clear from the spatula, and show not a burning, but a more salty taste. We would further remark that less salt is required for the sepa- ration of soap prepared with soda lye than for that with potash 20 306 MANUFACTURE OF SOAP AND CANDLES. lye, the quantity of salt necessary for the decomposition of the potash soap not being required. Salting out being completed the fire is removed for the time being to allow the soap to quiet down. A portion of the sub-lye is then pumped oif and the operation of clear boiling commenced, which is effected in the same manner as described for old German curd-soap. Many manufacturers prepare their curd-soap without boiling it clear upon sub-lye. The soap paste is only boiled clear and free from froth, and then carefully separated with salt or strong salt water so that no froth is formed, whereby a grain free from froth is obtained in the kettle. Curd-soap thus prepared gives a greater yield, but remains always very soluble, and when cut into bars frequently dries crooked. Such soaps can, however, be still more quickly and better prepared by means of steam. By the violent motion of the mass, produced by the admission of steam under strong pressure, the tallow is brought into more intimate contact with the lye and saponification is more readily effected, so that a large quantity of tallow is in a short time converted into a clear paste free from froth. For the fabrication of tallow (curd) soap with caustic soda lyes the process of boiling is the same as above. For pasting^ caustic soda lye of 10° to 14° B. is used. If in working old, somewhat rancid tallow, which contains, as is well known, more free fatty acids, the soap is rendered too caustic, which is indicated by thick and viscid boiling, some salt water of 20° B. is carefully added to remove this viscidity, or some soda solution where salt water may be too strong and exert an injurious effect upon the combination. By boiling old, rancid fats upon pure caustic soda lyes, defective curd-soaps are obtained, which is, however, also the case when fresh fats are boiled with lyes containing much alkaline carbonate. Marbling or mottling of tallow (curd)-soap. — When the opera- tion of clear boiling is finished, the fire is removed and the sub- lye allowed to settle. If the soap is to be marbled, the curd is either at once brought into the frame or first rendered somewhat more liquid by crutching in some hot water or weak lye, care being had not to work in any of the sub-lye. The soap being HARD SOAPS. 307 thoroughly crutched, the filled frames are covered with boards to permit the soap to become thoroughly heated and allowed to stand quietly. The soap becoming heated crystallization takes place, and, as it is technically termed, " grain' 7 and "flux" (Fluss) are formed. The grain is the crystalline portion of the soap and in- closes the non-crystalline (the flux), all the impurities and color- ing substances from the tallow, soda, etc., contained in the soap passing into the flux. Such soap, when cut, shows a more or less marbled appearance, and is therefore called marbled-curd soap. To make the marbling more prominent, bole elutriated in lye, pyrolysite, Frankfort-black, ultramarine, etc., are added towards the end of the boiling. These coloring substances being mechan- ically mixed with the soap deposit themselves in the flux. The marble in curd-soaps is allowed to form either sponta- neously or is drawn into "sheaves and flowers," i. e., after the process of formation is complete in the soap a different design is given to it by artificial manipulation, the design resembling either sheaves closely ranged alongside each other or flowers. The following is the process of producing sheaves : — When the soap in the frame has become sufficiently heated and set, which is recognized by the steam penetrating through the cracks between the boards, and shows the requisite fluidity, which otherwise has to be effected by crutching in some hot water, or weak lye, or by adding several pounds of cocoanut-oil, the process of producing sheaves is commenced after allowing the soap to somewhat cool off. A round iron rod, provided on top with a handle and below with a small button, is pushed into the soap down to the bottom. With this rod straight lines, as close to each other as possible, are first drawn the length of the frame and then the width. The closer and more uniform these lines are drawn the more beautiful the sheaves will be. Flowers are produced in the same manner ; flower-like designs being formed by skilful manipulation and twisting of the iron rod. Simple mottling, or sheaves and flowers, can, of course, be only produced when the soap is sufficiently hot, crystallization not taking place in soap brought too cold into the frame. Smooth white-curd soap is obtained either by crutching the 308 MANUFACTURE OF SOAP AND CANDLES. soap in the frame, of course without the addition of coloring matter, until it is observed to congeal, whereby crystallization is prevented and the small quantities of impurities uniformly dis- tributed, or the thick grain in the kettle is sufficiently ground. Grinding of soap. — The object of grinding is (1) to prevent the formation of marbling, (2) to purify the soap if necessary, and (3) to increase the yield by the absorption of water. The operation is performed by two different methods, either "from above 77 or "from below" but is always carried on with water or weak lye. Grinding from above is generally executed by crutching into the thick curd-soap in the kettle enough hot water or weak lye to sufficiently dissolve and liquefy the soap grains. During this manipulation soap which is too sharp, i. e., contains an excess of alkali, may, if necessary, be somewhat improved by grinding with water, by which the alkali is withdrawn into the sub-lye, or some causticity may be imparted to the soap by grinding with strong lye. Soap of right constitution is generally ground with weak lye (3° to 4° B.). After grinding the soap the kettle is covered with the lid and the soap allowed to stand a few hours for the impurities to pass into the sub-lye. Grinding from below is effected by pumping out or drawing off the sub-lye, then bringing the required quantity of weak lye, or water with an addition of salt to prevent the complete forma- tion of paste, into the kettle, and effecting the solution and lique- faction of the soap grains by vigorous crutching or gentle boiling. Grinding from below is only necessary with very impure mate- rials, and is but little practised at the present time. Utilization of sub-lye. — The sub-lye from curd-soaps contains common salt, the excess of alkalies used, the glycerin contained in the fats, frequently more or less soap, and the impurities from the fats and the lye. Though, as will be seen from the preceding, it contains valuable substances, it is seldom utilized by soap- boilers and generally allowed to run off, and where facilities for carrying it off are limited causes frequently great inconvenience. Usually an attempt is made to utilize the alkali contained in it by adding fat and boiling. The lyes which finally remain are HARD SOAPS. 309 seldom clear and thinly fluid, but generally thick and congeal to a jelly-like mass. The soap-boiler who is forced to allow such lyes to run off hot in order to obtain room for a new boiling, loses many pounds of soap contained in them. In many factories an attempt is made to utilize the sub-lye by evaporating it and selling it as so-called " fulling extract." Evaporation is generally effected over an open fire, though indi- rect steam is preferable. With an open fire constant stirring is absolutely necessary to keep the bottom of the kettle free, which otherwise would suffer injury and soon wear out. Evaporation is continued until a sample congeals to a jelly interspersed with small crystals of soda and salt. Deep soap-kettles are not well adapted for the operation, the evaporating surface being too small and stirring difficult and almost impossible the moment the sep- aration of crystals commences. Shallow pans can be highly recommended for the purpose, though they take up much space, of which there is seldom an abundance in soap-factories. In many factories the operation is carried on by evaporating the lye in a soap-kettle to the commencement of the separation of crys- tals and finishing in shallow pans. Independent of the profit gained by selling the fulling extract, this evaporation of the lyes has the further advantage of drawing attention to the immense quantity of soap contained in them. This content of soap varies with different fats, and, besides, de- pends on the manner of salting out, the lyes containing more soap if salting out has been effected by an excess of lye than by com- mon salt. However, not every thick, jelly-like sub-lye contains much soap, bone fat, for instance, yielding frequently such thick sub-lye, which is due more to glue than to soap. The jelly-like sub-lye from sulphur olive-oil is due to vegetable albumen. After boiling the sub-lye for some time a froth forms on the sides of the kettle ; this is removed and added in boiling resin grain-soaps. — Sub-lyes from resin grain-soaps are difficult to evaporate, they foaming very much at first and must be kept down by stirring.— To lyes containing very little alkali, which is readily recognized towards the end of evaporation, a few pounds of soda are added. The finished fulling extract is generally of a dark-brown color, 310 MANUFACTURE OF SOAP AND CANDLES. and is drawn off into old iron vessels, kettles, lye-kettles, etc., to cool, to be filled into barrels when an order is received. It has been previously mentioned that on account of the great content of common salt the regaining of glycerin from the sub- lye is a difficult matter. On treating glycerin with animal char- coal only a very small portion of the salt is removed and but little of it is carried over in distilling with superheated steam. These evils have for a long time prevented the utilization of sub- lyes for the recovery of glycerin, though many experiments have been made in this direction, however, without success. In 1880 and 1881, when crude glycerin was scarce, many patents were taken out for the purpose, one of which yields excellent results when crude glycerin is bringing a fair price. This is the process of recovering the glycerin by osmose, patented by H. Flemming, of Kalk. The reason why this process has not been generally in- troduced is partly due to a reduction in the price of glycerin and to the content of glycerin in the sub-lyes varying so much as to make its recovery in many cases unprofitable. In six different sub-lyes, Flemming found, for instance, 7.80, 6.70, 5.50, 4.75, 2.85, and 0.92 per cent, of glycerin. This variation in the con- tent of glycerin is readily explained by the difference in the raw materials, and the soap-boiler who uses them can judge which lyes are suitable for the recovery of glycerin, and exclude those not likely to prove profitable. To obtain the glycerin by osmose, the sub-lyes have to be evap- orated and freed as much as possible from the salts contained in them. For evaporating it is best to use a shallow pan, as shown in Fig. 74, which allows of a convenient removal of the separated salts, or Leon Droux's apparatus with revolving cylinder, shown in Fig. 75. It consists of the metal cylinder A B, with the hollow axles 8 S, through which the steam is admitted and later on discharged. The heating surface of the cylinder is consider- ably augmented by a number of ribs on its circumference. The cylinder dips into the fluid to be evaporated. By an arrange- ment, as seen in the illustration, the cylinder is slowly revolved, and with each revolution is covered with a thin layer of fluid which readily evaporates even at a comparatively low tempera- ture. The condensed water runs off at Z. The salts form an HARD SOAPS. 311 abundant deposit on the surface of the cylinder, and can be read- ily removed by means of a hammer or by dipping into a less concentrated liquid. FiAPS. Curd-soaps. Grounc -soaps. Marbled. White. Marbled. White. White. Marbled. White. per cent. per cent. per cent. per cent. per cent. per cent. per cent. Water . . . 10.15 14.5 15.50 21.36 45.2 23.94 27.45 Fatty acids 76.00 76.5 72.00 68.40 50.2 67.16 62.80 Sodium oxide- Fixed . . 8.65 9.0 8.00 10.24 4.6 7.82 9.15 Free . . . 0.25 — 0.45 — — — 0.20 Foreign salts, residue \ 4.95 1 — 4.05 — — 1.08 0.40 " 320 MANUFACTURE OF SOAP AND CANDLES. Marseilles soap from olive-oil fatty acid. — In ■ modern times, as previously mentioned, the glycerin is frequently extracted from neutral fats, such as olive-oil, palm-oil, tallow, etc., before work- ing them into soaps. For this purpose the fats are saponified in autoclaves, and the fatty acids obtained frequently distilled with superheated steam in order to obtain them white. Such a refined fatty acid obtained from olive-oil is of a lardaceous consistency and a pale-yellow color, and is frequently used in Germany for the manufacture of Marseilles soap. The boiling process differs somewhat from the ordinary one and is briefly as follows : — The required lye of 12° to 15° B. is brought into the kettle, and when boiling a small quantity of the fatty acid is added with thorough crutching. After the solution of the fatty acid in the boiling lye, other portions of the fatty acid are gradually added, care being had to see that one portion is entirely absorbed by the lye before adding the next. This is continued until a clear, thick paste is formed. When a sample brought in contact with the tongue shows a slight touch, the addition of fatty acid is inter- rupted. After allowing the paste to boil a short time it is finally salted out with lye of 30° B. The grain is then boiled clear in the same manner as tallow (curd) soap, and after removing the sub-lye thoroughly ground and fitted. After standing overnight in the covered kettle, the soap is ladled into small shallow frames and crutched cold. Marseilles soap thus manufactured is very white and solid. Palm-oil [curd) soap.- — Palm-oil contains a large amount of palmitin, and is readily saponified either by itself or in connec- tion with other fats, such as tallow, bone-fat, olein, etc., the soaps thus prepared being much liked in the various branches of the textile industry as well as in the household. Comparatively little palm-oil is used in a crude state, it being generally bleached before use to remove the coloring substance and. other impurities. . Pure palm-oil soap is prepared in the following manner : A determined quantity of bleached palm-oil and a portion of the required lye of 14° B. (about 550 pounds of lye to 1000 pounds of oil) are brought into the kettle. With a slow fire and crutch- ing an emulsion is soon formed, and, when ebullition is reached, the fat will intimately combine with the lye. When this is the HARD SOAPS. 321 case more lye ol 14° B. is added, whereby the mass is gradually converted into paste, which, after continued boiling and the fur- ther addition of lye of 14° B., becomes thicker and shows a clear uniform appearance. When a sample of the paste upon a glass plate remains quite clear up to the congealing point and causes a slight burning sensation upon the tongue, the saturation of the paste with alkali may be considered complete (about 2500 pounds of lye of 14° B. suffice for the complete saponification and satu- ration of 1000 pounds of oil). The paste is now either boiled until entirely free from froth and then carefully separated, so that no froth is formed, with common salt or salt water of 24° B., the result being a thick grain free from froth ; or the paste is boiled not entirely free from froth but salted out when it spins threads, and after removing a portion of the sub-lye the grain is boiled clear like tallow soap. For marbled soap the slightly colored paste is brought into the frame and the latter covered after thorough crutching. For smooth soap the grain is well ground by crutching in hot water, or, what is still better, potash lye of 3° to 4° B, until it has ac- quired sufficient fluidity to allow all the impurities to pass into the sub-lye. Soap prepared from palm-oil soon develops an agreeable odor of violets and yields a thick, fat lather. 100 pounds of palm-oil yield on an average 150 to 155 pounds of soap, which is aug- mented about 10 pounds by grinding. Besides bleached palm-oil the crude oil is also frequently used in England. Soap prepared from it retains the odor of palm-oil, and has the disagreeable property of causing brownish stains difficult to remove in clothes remaining long in contact with it. In England the boiling of palm-oil is effected in steam-kettles with double sides, from six to eight of such kettles being con- nected with the steam-boiler. The large quantity of free fatty acids in palm-oil, which is still further augmented by bleaching, facilitating and promoting saponification, lyes of 18° to 20° B., which, however, should contain no free sodium carbonate, is therefore used from the start. Fitting is effected by two methods : the paste is either salted out in the same manner as tallow-curd soap or Marseilles soap, or, as 21 322 MANUFACTURE OF SOAP AND CANDLES. is more frequently done, the soap is separated from the sub-lye by stronger lyes. According to Stoeck- hardt, 1, 2, and 4; 1 2 3 4 5 6 Schaedier, 3, 5, and 6. Pure Palm-Oil Soaps. Curd-soaps. Ground-soaps. Bleached. Un- bleached. Un- bleached. Bleached. Marbled. Un- bleached. Water Fatty acids . Sodium oxide- Fixed ... Free .... Foreign salts Residue .... per cent. 24.8 61.2 8.0 1.7 1.3 3.0 per cent. 19.9 65.2 8.6 1.2 1.8 3.3 per cent. 15.6 72.5 8.6 0.2 3.1 per cent. 35.4 49.9 7.0 1.0 1.1 5.6 per cent. 40.3 45.8 6.5 0.9 6.5 per cent. 29.4 55.0 6.5 1.2 4.5 3.4 100.00 100.00 100.00 100.00 100.00 100.00 Soap prepared from pure palm-oil being somewhat hard and brittle, the oil is generally worked in connection with softer fats, such as bone fat, olein, lard, peanut-oil, etc., or with 15 to 25 per cent, of resin. In the following we will describe a few such soaps prepared from palm-oil with an addition of other fats or resin. Stettin palm-oil household soap. — Eight hundred pounds of palm-oil and 200 pounds of bone fat and 500 pounds of lye of 12° B. are brought into the kettle and combined by crutching over a slow fire. As soon as the mass is thoroughly combined more lye of 12° to 14° B. is added, and the whole allowed to boil thoroughly, the addition of lye, with vigorous boiling, being con- tinued until a pale, clear paste is formed and a sample of it brought upon the tongue shows a slight touch. For the saponi- fication of the 1000 pounds of fat about 2500 to 2600 pounds of lye of 12° to 14° B. suffice. Now add to the saturated, clear soap-paste, with constant vigorous stirring, in small portions, 150 pounds of pale comminuted resin and 150 pounds of caustic soda lye of 20° B., and allow the whole to combine with gentle boiling. When, after a few hours, the paste is clear and shows a HARD SOAPS. 323 slight touch and a sample " wets" (shows moisture) and slides upon a glass plate, salt well out with salt water of 24° B. and boil the resulting grain clear. Now cover the kettle, and after allowing it to stand for a few hours to give the sub-lye time to settle, ladle the grain into small, low frames so that it cools rapidly. The soap is cut into rectangular pieces and pressed on all four sides. Many manufacturers prepare this soap in the cold way. The process is briefly as follows : 50 pounds of bleached palm-oil and 7 pounds of pale resin are brought into the kettle and melted. After cooling to about 111° F., the fatty mass is combined by stirring with 10 pounds of caustic soda lye of 38° to 40° B. Now add 20 pounds of soda water-glass of 38° B., stir in 20 pounds of caustic soda lye of 38° to 40° B., and bring the well- combined soap-mass into the frame. If the greater portion of the lye were immediately combined with the fat and the water-glass then added with a few pounds of lye, the mass would become thick and difficult to bring into the frame, which is prevented by the simultaneous addition of lye and water-glass. This soap is also cut into rectangular pieces and pressed, and after lying for some time shows an agreeable violet odor. It is, of course, not a curd-soap. Soap from palm-oil and hone fat— -Bring about 450 pounds of bleached palm-oil and 150 pounds of pale, purified bone fat into the kettle, and add about 350 pounds of lye of 12° to 14° B., and let all thoroughly combine over a moderate fire. Combina- tion being effected, increase the fire and add more lye of 14° B., continuing this until a light, clear paste is gradually formed. When the paste is completely saturated with alkali, and a sample upon a glass plate remains clear until it congeals, and shows touch, boiling is continued for a little while longer, after which the paste is salted out. The soap being separated, a portion of the sub-lye is pumped out and the grain boiled clear in the same manner as tallow soap. Clear boiling being finished, the kettle is covered and allowed to stand a few hours to give the sub-lye time to settle. The paste is then brought into low frames (only about four 324 MANUFACTURE OF SOAP AND CANDLES. inches high) and the surface of the cooled soap scarred with a round stick to give it the desired rough appearance. Soap from palm-oil and resin or colophony.' — This soap has a beautiful wax-like appearance, is readily soluble on account of the addition of resin, yields a stiff lather, and possesses good de- tergent properties. For the manufacture of the soap bring 425 pounds of bleached and 75 pounds of crude palm-oil and 250 pounds of tank-lye or caustic soda lye of 14° B. into the kettle and combine them over a moderate fire. Then add more lye of 14° B. and increase the fire. After continued boiling and adding more lye, the mass gradually forms into paste, which becomes thicker and clearer the further its saturation with alkali pro- gresses. The oil being completely saponified, which requires about 1250 pounds of lye of 14° B., and the thick, clear paste showing a slight touch, 150 pounds of comminuted pale resin and caustic soda lye of 20° B. are added in portions until the paste is thoroughly fitted, a very moderate fire being kept up during the operation. For the saponification of the resin about 150 pounds of caustic soda lye of 20° B. will be required. The sufficient fitting of the paste is recognized not only by a slight touch, but better and surer by a sample upon a glass plate, which, with thorough fitting, will slide upon the glass and show moisture. The fitted paste is thoroughly salted out and the resulting grain, after pumping out a portion of the sub-lye, boiled clear so that it lies thick and free from froth in the kettle and a sample shows solidity and pressure. For marbled soap or soap showing sheaves and flowers, the paste, after clear boiling and settling of the sub-lye, is ladled into the frames and the latter are covered. The manipulation of marbling, etc., is then commenced in the same manner as de- scribed for tallow soap. For smooth soap the clear-boiled grain has to be ground. For this purpose the greater portion of the sub-lye is removed and the grain ground with hot water until the sub-lye begins to thicken and the grain is completely dissolved and lies bright in the kettle. A sample should show sufficiently solidity, but no touch. In grinding care must be had that the soap does not be- HARD SOAPS. 325 come too pasty or too soft. After settling and resting for some time, the ground soap is ladled into the frames. Some manufacturers prepare this soap by the following process : The palm-oil is first completely saponified with lye of 14° B. The clear fitted paste is then salted out, and, after removing the sub-lye, the resin is added and saponified with caustic soda lye of 20° B. The soap, after salting out, is boiled until it is free from froth and clear, and a sample is solid with a good pressure. The soap is finally ground with some water. This process also yields a beautiful product. Palmitin soap. — Under this name a soap is brought into com- merce by some manufacturers, which is prepared chiefly from palm-oil fatty acid in connection with a small quantity of other fats. Palm-oil fatty acid is a white solid fatty substance, and is obtained by withdrawing the glycerin from palm-oil, and sub- jecting the crude fatty acid obtained to distillation with super- heated steam. As fatty acids saponify very quickly, the manner of preparing soap from them varies somewhat from that employed for neutral fats, saponification being best effected by means of stronger lye containing more carbonic acid. A suitable method of boiling is as follows : 2000 pounds of lye of 18° B. (required for 1000 pounds of fat consisting of 3 parts of palm-oil fatty aciji and 1 part of saponified olein) are brought into the kettle and heated to boiling. The above quantity of fatty acids is then added in portions with constant crutching to the gently boiling lye and at once saponified. In adding the fatty acids the utmost care is necessary not to add a fresh portion before the preceding one has been completely absorbed by the lye. When a clear paste is formed, it is fitted to touch, allowed to boil for some time longer, and then salted out. The resulting grain is then boiled clear in the previously mentioned manner, and, after removing a portion of the sub-lye, ground with water until a cohesive liquid mass is formed. The soap is now allowed to rest for twenty-four hours in the covered boiler, and then carefully ladled from the thinly-fluid paste beneath it into large frames and covered. In cutting, the soap 326 MANUFACTURE OF SOAP AND CANDLES. shows a silvery radiated appearance and also an agreeable odor. The yield from 100 pounds of fat is about 160 pounds of soap. Resin curd-soaps. — The resins used are galipot and colophony. They liquefy at the boiling heat of water, and saponify more readily and quicker than the fats. Saponification can be effected by means of sodium carbonate or caustic soda, the latter being, however, preferable. The formula C 40 H 60 O 4 = 608 molecular weight may stand for common resin or colophony, which is a mixture of several iso- meric acids ; 1 molecule of acid saturates 1 molecule of sodium or potassium oxide, therefore 608 parts, 62 parts of sodium oxide or 94 parts of potassium oxide, or 100 parts of resin require 10.2 parts of sodium oxide or 15.5 parts of potassium oxide for saponification, or 220 pounds of resin, 220 pounds of soda lye of 19° B., or the same quantity of potash lye of 17° B. The result- ing product is not an actual soap, it having no consistency, and cannot be used without injury. With an excess of alkaline car- bonates common salt separates upon the surface a soft thickly- slimy mass, while a portion of the soap remains dissolved in the sub-lye into which pass also in an unaltered state the brown coloring substances, as well as certain constituents of the resin. However, if resin is saponified in connection with other fats, common salt solution separates out all the resin-soap together with the fat-soap. A solid soap cannot be prepared from pure resin, strong alka- line lye not separating pure resin-soap but remaining mixed with it, and hence the soap remains always smeary. It does not dry on exposure to the air, and the power of resin-soap artificially dried of absorbing water is so great that it deliquesces. Though resin-soap by itself is of no value, an excellent and solid product is obtained by combining it in certain proportions with tallow-soap or palm-oil soap. The most suitable proportion of resin to fat is one-third ; with equal parts the property of pure resin-soap predominates more or less, the soap becoming too soft. The following may serve as combinations : — HARD SOAPS. 327 Parts. Parts. I. Palm-oil . . 50 II. Palm-oil . . 50 Tallow . 30 Cotton-seed oil . 20 Resin . 20 Resin . 30 Parts. Parts. I. Palm-kernel oil . 40 IV. Tallow . . 25 Palm-oil . . 20 Palm-oil . . 25 Resin . 40 Resin . 50 In England the crude palm-oil is melted in kettles and pumped into cast-iron reservoirs, where it is kept liquid for the impurities to settle. The reservoirs are placed near the soap-kettle, and are provided with a float-gauge, which indicates how much oil is dis- charged. For 3J parts of palm-oil 1 part of resin is used. Resin-soap having a brownish-yellow color it is not necessary to bleach the palm-oil, and other waste fats, such as bone fat, wool fat, etc., can also be utilized. However, if bleached palm-oil is to be used it is best in order to obtain a white soap to first purify and bleach the resin. Resin soaps are prepared according to different methods, a few of which will be given in the following : — Resin curd-soap (30 pounds resin to 100 pounds fat). — An old method of preparing resin-soap, which was formerly much in use, is as follows : Combine by moderate boiling 1000 pounds of tallow and 150 pounds of crude palm-oil with 700 pounds of lye of 10° B. When combination is complete increase the fire and add gradually to the boiling mass lye of 12° to 14° B. until a clear paste is formed. When the paste is thoroughly saponified, continue boiling until it lies free from froth in the kettle, and a sample shows clear and solid upon a glass plate and causes a slight touch when brought upon the tongue. At this stage salt out the paste and the result will be a thick grain free from froth. Allow it to rest for some time in the covered kettle for the sub- lye to settle. In the meanwhile saponify in another kettle 350 pounds of resin by adding lye of 20° B. (about 650 pounds) until the com- plete saponification of the resin is indicated by lye separating from a sample. As the separated lye absorbs all the impurities and the greater portion of the coloring substance of the resin, the resin-soap obtained is alw T ays of a light color. 328 MANUFACTURE OF SOAP AND CANDLES. The sub-lye is now pumped off from the grain-soap in the other kettle and the dirty lye from the resin-soap. Then add the resin-soap to the grain-soap, and mix both by vigorous stirring or the admission of steam. The soap is generally boiled upon a second water by liquefying the grain with lye of 6° to 7° B., then boiling for some time, and again concentrating it with lye of 2° to 3° B. so that a somewhat thin precipitate of paste is formed. After allowing the soap thus obtained to rest several hours it is framed ; when cut it is of a beautiful appearance and great solidity. Resin curd-soap (40 pounds resin to 100 pounds fat). A beautiful and cheap resin-soap is prepared by the following process : 500 pounds of bone-fat, 400 pounds of tallow, 100 pounds of crude palm-oil, and 700 pounds of lye of 12° B. are brought into the kettle and intimately combined by crutching over a slow fire. The fire is then increased and lye of 14° B. is gradually added until a clear, homogeneous paste is formed. This will require about 1800 pounds of lye of 14° B. The ad- dition of lye is best executed by allowing one portion to thor- oughly combine with the mass before adding another. When a sample of the paste remains clear for some time upon a glass plate and shows a slight touch, vigorous boiling is continued until the paste is quite free from froth. The paste is then salted out, about 8 to 10 per cent, of salt of the fat used being sufficient for the purpose. After thorough settling the sub-lye is pumped out or drawn off. The caustic soda lye of 20° B. (about 400 pounds) required for the 400 pounds of resin is then added and the soap boiled clear, The comminuted 400 pounds of resin are then added in portions and saponified with a moderate fire. The soap is then boiled until it lies free from froth in the kettle and shows good pressure. It is then thoroughly fitted and separated, and finally somewhat ground with water. The saponification of the resin with strong lye is of advantage, since the formation of froth is promoted by the great content of moisture brought into the soap with the use of weak lyes. Resin curd-soap (50 pounds resin to 100 pounds fat). — Nine hundred pounds of tallow, 100 pounds of crude palm-oil, and 500 pounds of pale resin are brought into the kettle and com- HARD SOAPS. 329 bined with 600 pounds of caustic soda lye of 15° B. with a mode- rate fire. Combination being established, increase the fire some- what and add lye of 15° B. in portions until a quite clear paste is formed. Then add caustic soda lye of 25° B., and boil until the paste lies free from froth in the kettle, and a sample pressed in the palm of the hand leaves moisture behind, which is a better and surer test than the touch, of the complete saturation of the paste. After salting out the soap is boiled thick and clear, and the resulting grain is ground with some hot water. After stand- ing about twelve hours in the covered kettle the soap is framed and crutched until cold. Resin curd-soap, according to the American method (100 pounds resin to 100 pounds fat). — Nine hundred pounds of tallow and 100 pounds of crude palm-oil are brought into the kettle and in- timately combined, by a moderate fire, with about 600 pounds of lye of 12° B. The fire is then increased and lye of 12° to 13° B. added in portions (each time about 200 to 300 pounds) until a good clear paste is formed. After withdrawing by continued boiling superfluous water from the paste, and the latter lies free from froth in the kettle and shows a slight touch, it is salted out. The sub-lye is then removed, and about 900 pounds of caustic soda lye of 25° B. are added to the grain, and then gradually the 1000 pounds of comminuted resin. The whole is then boiled until the resin is thoroughly saponified. By fitting to a good touch with lye of 25° B. a quite solid soap is obtained. The sub-lye is then again removed, the soap thoroughly ground with hot water, again fitted, and finally allowed to rest in the well- covered kettle for 24 to 36 hours. The soap is then brought into the frames, and having become somewhat soft by grinding a strong solution of crystallized soda (about 5 or 6 pounds to 100 pounds) is crutched in which renders the soap firmer. . Sometimes 1 to 2 pounds of soda-water glass are added to the soda solution, which prevents the disintegration of the soap and is beneficial to its appearance. Dark resin curd-soap. — For the preparation of dark resin- soap, which is frequently used for household purposes, scrubbing, etc., kitchen-fat, wool-fat, fuller's-fat, bone-fat, palm-kernel oil, and dark resin are generally employed. 330 MANUFACTURE OF SOAP AND CANDLES. The boiling of this soap is mostly executed by combining, for instance, 500 pounds of bone-fat, 200 pounds of kitchen-fat, and 300 pounds of wool-fat with about 500 pounds of lye of 12° B., and boiling the mass over a stronger fire, and with a further gradual addition of lye of 12° to 15° B., to a good paste. When saponification is complete and a sample shows a slight touch, 200 pounds of dark resin and about 180 pounds of caustic soda lye of 20° B. are added and allowed to combine over a moderate fire. The paste is allowed to boil vigorously for some time, and then fitted by carefully adding lye of 25° B. until a sample leaves moisture behind and slides upon a glass plate. The paste is then salted out, the resulting grain boiled clear in the usual manner, and the evaporated thick soap ground with hot water until the sub-lye commences to paste. For marbled soap the paste is brought into the frames, drawn through with an iron rod, and w T ell covered. Having given in the foregoing the various methods of boiling resin-soaps, it remains to say something in regard to the fabrica- tion of these soaps. First, it is always advantageous to use only pure fat and resin. To attain this it is best to melt the fat upon water and dissolve the resin in the hot fat. After such an opera- tion it will be generally found that the water is not only strongly colored, but that a thick sediment has formed upon the bottom of the kettle. Secondly, it is necessary in order to prevent the formation of froth to saponify the resin with strong caustic soda lyes, and besides care must be had to saturate the resin by a successive addition of lye. Thirdly, the fitting of resin-soaps must be only slight, since soaps with an excess of soda decompose. For a similar reason the use of caustic soda lye for resin-soaps is recommended, as this will frequently prevent sweating, for only soaps containing sodium chloride or much sodium carbonate, which attract moisture from the air, sweat. In the following we give a few analyses of resin-soaps : — HARD SOAPS. 331 According to Ure, 1 ; Stein, 2 and 3. 1 2 3 Rksin-Soaps. Brown tallow and resiu. English. Light palm-oil and resin. Water ..... Fatty acids, etc. . Sodium oxide Foreign salts and residue per cent. 23.50 70.00 6.50 per cent. 22.23 62.95 8.03 6.79 per cent. 26.94 63.42 7.19 2.45 100.00 100.00 100.00 Olein-soap. — For the manufacture of candles only solid fatty acids can be used, and, therefore, after the decomposition of the fats, oleic acid is obtained as a by-product by pressure. The oleic acid thus obtained is a mixture of a small quantity of solid fatty acids (palmitic and stearic acids) with a large quantity of actual oleic acid and its product of decomposition, sebacic acid, etc., and other organic substances formed by the action of sulphuric acid upon the fat. Commercial oleic acid, also erroneously called "olein" or "elain," is of a brown color due to the absorption of oxygen from the air, and can be saponified with the carbonates of the alkalies as well as with caustic alkalies. The treatment with the carbonates is, however, more difficult, since strong foam- ing and consequent boiling over are caused by the escape of the carbonic acid. Two varieties of oleic acid are found in commerce, saponified oleic acid and distilled oleic acid. The first variety, which generally contains a few per cents, of stearic acid, gives quite solid soaps with a yield of 1 50 pounds of soap from 100 pounds of fat, while the distilled oleic acid gives generally a soft product Avith a smaller yield (about 140 pounds). The latter is, there- fore, principally used in connection with palm-kernel oil for smooth soaps, whereas good soaps can be prepared from saponi- fied oleic acid without the addition of other fats. The manner of preparing pure olein soap is similar to that given for olive-oil and palm-oil fatty acid. The most simple and advantageous method of manufacture is as follows : — 332 MANUFACTURE OF SOAP AND CANDLES. Tank-lye of 22° B., prepared with 50 to 52 per cent, of lime, is brought to from 27° to 28° B. by caustic soda. Nearly the entire quantity of lye required (about 1 pound lye to 1 pound oleic acid), with some salt, is brought into the kettle and the oleic acid added in portions, while the lye is kept in constant ebullition. By these means a uniform combination is effected, and by the use of strong lye the formation of froth prevented. If, after the complete saponification of the oleic acid and fitting to touch, some salt is wanting, it is added, and the soap will then be generally found lying in the kettle as a good grain free from froth, so that clear boiling can in most cases be omitted. After thorough set- tling the sub-lye is pumped out or drawn off and some lye of 7° B. is brought into the kettle, with which the grain is boiled for some time, so that it becomes completely saturated with alkali. The soap is then ground with water until the sub-lye commences to paste slightly. The kettle is then covered and allowed to stand 12 to 18 hours, when the soap is carefully ladled off from the slight precipitate into the frames and the latter are covered. On cutting, the soap thus prepared shows a fine silvery radi- ated appearance and is delicate and quite firm ; but if it is to be cut into square pieces and pressed or stamped, it has to be en- tirely smooth. For this purpose it is allowed to stand in the kettle for 24 to 30 hours, and is crutched in the frames until cold. If, in order to increase the solidity of- the soap, some bleached palm-oil is to be added, it can only be done after the oleic acid has exhausted the strength of the strong lve in the kettle, when the palm-oil is added together with the required lye. Before subjecting the oleic acid to saponification it is frequently converted into the isomeric elaidic acid by means of nitrous acid, a small quantity of the latter sufficing for the conversion of a large' quantity of oleic acid into the isomeric combination, which is as hard as tallow. It yields a beautiful soap which resembles tallow-soap and can be worked into grain-soap or ground soap. Soap from fuller's fat. — A soap has been recently introduced into commerce which is prepared chiefly from fuller's fat, and, on account of its large content of fatty acid (about 62 per cent.), is HARD SOAPS. 333 much used in the cloth industry and sometimes for household purposes. Fullcr's-fat is recovered by decomposing the soap-waters from cloth mills with sulphuric acid, a product of quite a light color being obtained after passing it through various operations. The value of fuller's fat varies very much, according to the quality of the soap used in the mills. The color of the fat is also of im- portance, as dark fat requires to be boiled upon several waters, and the appearance of the resulting soap is less desirable. Ful- ler's fat being a pure fatty acid, is readily saponified in a similar manner as oleic acid, and under certain conditions may yield a good grain-soap. Generally, however, it is boiled in connection with other solid fats, the resulting soap having a better appear- ance and feel. Soap from fuller's fat is generally prepared by bringing about 1000 pounds of tank-lye of 15° B. into the kettle, and after heat- ing to the boiling point, adding 50 to 60 pounds of common salt. The fire is then moderated and the fuller' s-fat (about 500 pounds) gradually introduced. In adding the fat great care must be ob- served and water or weak lye always kept ready on hand, as on account of the escape of carbonic acid the mass may foam up and run over. Saponification is generally complete after crutching in all the fat. A small excess of lye is of advantage, as it promotes the decolorization of the fat. The soap lying in the kettle as a small round grain is allowed to boil for some time with a moderate fire, when 50 pounds of comminuted resin and about 40 pounds of caustic lye of 20° B. are added. Boiling is now continued until a round grain is again formed, which is fitted. After extinguishing the fire and allowing the sub-lye to settle, the soap is ladled into large barrels and the dirty sub-lye allowed to run off. The soap, together with some other cheap fat and soap offal, is then returned to the clean kettle, sufficiently evaporated by gentle boiling, and care- fully and slightly fitted with caustic lye of 20° B. When a sample, after cooling, is dry and without sharpness, the operation is finished and the soap brought into the frames. For a lighter and more solid soap the resin is omitted, and after removing the sub-lye and thoroughly cleaning the kettle, 334 MANUFACTURE OF SOAP AND CANDLES. about 250 pounds of lye of 25° B. are added and the whole al- lowed to boil. Now add to the boiling grain, carefully and gradually, about 100 pounds of oleic acid, and when this is thoroughly dissolved, 150 pounds of palm-oil or palm-oil fatty acid. The soap, which will soon be thoroughly combined and liquid, is then salted out, boiled clear, and somewhat ground with weak lye. Some factories purify the fuller's-fat by distillation with super- heated steam and bring it into commerce under the name of " solid white olein." It is principally used for grain-soaps upon a precipitate of paste and resin grain-soaps, which are firm and of good appearance. Wool-fat soap. — Under the name " wool-fat" a brown, sticky, and quite solid fat is brought into commerce, which is obtained by washing crude sheep's wool with soap and decomposing the resulting wash-water with acid, etc. Wool-fat is not counted among the actual fats, since, when boiled by itself, it does not yield serviceable soap. In connection with other fatty substances it yields, however, a fair curd-soap. To obtain wool-fat entirely free from water and dirt it is frequently purified by boiling it for some time upon salt water of 16° B. and carefully ladling it oif the next day. To manufacture curd-soap with a portion of wool-fat the fol- lowing process is used : 250 pounds of bone-fat and 50 pounds of crude palm-oil are combined with 150 pounds of lye of 12° B. over a moderate fire. The fire is then increased and lye of 12° to 15° B. gradually added until a clear paste free from froth is formed, which is fitted to a slight touch. About 200 pounds of wool-fat and the required 200 pounds of lye of 22° B. are then added to the paste, and after thorough combination is estab- lished the whole is allowed to boil some time longer. Now slacken the fire and add gradually 50 pounds of comminuted resin, together with about 40 pounds of caustic soda lye of 20° B., carefully fit the paste after further boiling with caustic soda lye of 25° B. until a sample shows moisture, and then salt out. The dark sub-lye is now removed and a few bucketfuls (only sufficient to prevent scorching) of light sub-lye derived from curd-soap are thrown into the kettle, and boiling is continued HARD SOAPS. 335 Until a thick grain free from froth and without sharpness is formed. The soap is then brought into the frames, drawn through with a rod, and well covered. Wool-fat is also purified in the same manner as fullerVfat by distillation, and then comes into commerce under the name of " cholestrin." It is a solid, white product, and on account of its better appearance can be used for various light hard soaps. Curd-soap from fish-tallow. — Under the names of " whale-fat 7 ' and " fish-tallow," two fatty substances have been recently brought into the market. Several soap-boilers have made ex- periments with these fats, but on account of their intense fishy odor, which strongly adheres to soaps manufactured from them and the present low price of tallow, their general introduction is not likely. Of the two fats fish-tallow, which is the stearic portion ob- tained by pressure from fish-oil, deserves the preference, since, in connection with other fats and resin, it may serve for the prepa- ration of yellow soaps of fair quality. It is of a brownish color and quite firm, and saponifies with tank-lye as well as with caustic soda-lye. 100 pounds of fish-tallow yield about 130 pounds of curd-soap. The manufacture of yellow curd-soap is generally effected in the following manner : About 400 pounds of fish-tallow, 25 pounds of crude palm-oil, and 250 pounds of lye of 12° B. are brought into the kettle and combined over a moderate fire. The mass is then allowed to boil vigorously, more lye of 15° B. being gradually added until paste is formed. The paste is vig- orously boiled, with the addition of the lye still required, until it is clear and free from froth, and is then fitted to a slight touch with caustic soda lye of 20° B. The fire is then moderated, and 50 pounds of comminuted resin are gradually added, together with 40 pounds of caustic soda lye of 20° B. When the resin has combined with the rest, boiling is continued with a further addition of lye of 20° B. until a sample of the paste shows moisture, which indicates the complete saponification of the resin. Salting out is then proceeded with. For this purpose salt soaked in water is gradually added until separation is effected and the grain boils in beautiful laminae, and a sample pressed in the palm 336 MANUFACTURE OF SOAP AND CANDLES. of the hand does not smear but is firm and dry. After allowing the soap to rest for some time, the very dark and jelly-like sub- lye is removed and a few bucketfuls of light sub-lye derived from a white curd-soap are brought into the kettle. Boiling is now continued until a thick grain free from froth and without sharp- ness is formed, which, after settling, is ladled into the frames and well covered. By clear boiling upon salt-lye the grain acquires a considerably lighter color, and by the addition of resin the odor of train-oil becomes less perceptible. The odor of fish-tallow is, however, so powerful as to make it impossible to use large quan- tities of it, as even with an addition of only ten per cent, the odor of train-oil is clearly perceptible. Apollo soap.- — -To prepare the so-called Apollo soap, which is a ground olein-soap, the quantity of lye of 20° to 22° B. required for the saponification of the oleic acid to be used is brought into the kettle and some salt added. The object of the addition of the latter is to prevent a complete pasting of the mass, since this would be a hindrance to the complete saponification of any oleic acid which may still be wanting. The process of fabrication is briefly as follows : 5000 to 5300 pounds of lye of 22° B. are brought into the kettle and heated to boiling. Five thousand pounds of oleic acid are then gradu- ally added with constant crutching. Saponification takes place almost instantly and without the formation of froth. The soap boils either in dark broad laminae, or, if the fire is somewhat strong, in grains. At this stage a few bucketfuls of lye of 5° to 6° B. are added, which makes the saponification more complete. The soap is then fitted to a slight touch and salted out. It now lies as a beautiful, thick grain of a honey-yellow color in the kettle and might be considered finished, but is generally allowed , to rest three to four hours in the kettle for the sub-lye and the dirt to settle. After removing the sub-lye and the dirt about 2000 pounds of soda lye of 5° to 6° B. and sufficient salt are brought in the kettle, so that the soap remains separated and will not form froth. It is then again thoroughly boiled. The soap is then fitted to a slight touch with lye of 20° B., and should it seem too grainy is HARD SOAPS. 337 ground from above with some hot water until the grain is liquefied. The soap is now more solid and shows a good pressure. It is then crutched through and allowed to stand, if possible over- night, in the covered kettle. The next day any froth thrown out is carefully removed and the soap brought into the frames. In many factories small iron frames holding ten to twelve hundredweight are used and the soap is crutched until cold, whereby it is rendered entirely smooth and ready for cutting in three to four days, but shows no grainy silver stripes. Slow cooling in large frames well covered is to be preferred, though it is advisable to crutch the soap for a few minutes after it is brought into the frames. When the soap is cold it is cut into slabs, which are somewhat dried and then cut into bars. The latter are stamped, dried in the air, and stored for at least three to four weeks before they are brought into commerce. This soap is not only an excellent one for fulling cloth and for other textile pur- poses, but also for household use. It is largely manufactured in Austria, having been first introduced at the celebrated Apollo candle factory at Penzing, near Vienna, whence its name is de- rived. The material used there is the oleic acid obtained as a by-product in the manufacture of stearin, and is brought into commerce under the name of " Vienna elain." It is of a pale yellow color, very rich in stearin, and yields excellent soaps. Turpentine soap. — This soap was formerly prepared from equal parts of tallow and palm-oil, 8 to 10 per cent, of cocoanut-oil, and 20 to 25 per cent, of pale resin. The tallow and palm-oil were saponified with lye of 15° B., boiled clear, and the resin soap, previously prepared in another kettle, crutched in. The whole was then strongly fitted and the soap ground with 8 to 10 per cent, of cocoanut-oil. The resulting soap was very good,, but would be too expensive at present prices. Since the introduction of the cheap palm-kernel oil and caustic soda the following process is generally adopted : — Two thousand pounds of palm-kernel oil and 600 pounds of pale resin, previously comminuted, are saponified with about 4000' pounds of caustic soda lye of 23° B. The resin combining very 22 338 MANUFACTURE OF SOAP AND CANDLES. quickly and readily with the strong lye, facilitates the combina- tion of the palm-kernel oil with the alkali. The soap is now fitted to a slight touch. About 80 to 100 pounds of crude palm-oil, together with the required lye, are then added for coloring, and after boiling until the froth entirely disappears, the soap is strongly salted out with caustic soda lye of 35° to 36° B. and some salt. The resulting stiff grain is then ground with hot water. The kettle is then covered and the soap allowed to stand over night for the sub-lye to settle. The next day the soap is framed and crutched for about one hour. Should any sub-lye be inadvertently ladled into the frame, add a few pounds of palm-kernel oil and crutch thoroughly. Before allow- ing the soap to rest it is perfumed with five pounds of oil of tur- pentine and then well covered. Russian saddle soap. — This soap is a specialty with some German manufacturers. The following materials are used : 1000 pounds of Russian tallow, 400 pounds of erode palm-oil, 560 pounds of Ceylon cocoanut-oil, and 400 pounds of pale resin. The soap is boiled either by the direct or indirect method. For the direct method a sufficient quantity of caustic soda lye of 25° to 26° B. for the saponification of the above-mentioned materials is brought into the kettle. If any soap-cuttings are on hand they are allowed to dissolve in the lye. The tallow is then added, next the palm-oil, cocoanut-oil, and finally the resin. Should the resulting paste be viscid and thick, add gradually lye of 25° to 26° B. until the paste is clear and well fitted. The soap is then boiled until laminae are formed. It is then salted out and ground with hot water until a sample " wets," i. e., leaves moisture behind. The soap is now left in the well-covered kettle till the next day, when it is brought into small frames holding about three to six hundredweight each and crutched cold. It is cut into five-pound bars and stamped. For boiling the soap by the indirect method, the tallow, palm- oil, and resin are brought into the kettle and saponified with soda lye of 20° B. The mass is then boiled to a clear paste which is fitted to a slight touch and salted out. The soap-cuttings are then dissolved in another kettle in lye of 20° B. and the cocoanut- oil added. The grain in the other kettle is then brought into the HARD SOAPS. 339 one containing the soap-cuttings and cocoanut-oil and the soap is finished in the above-described manner. Sinclair's soap. — Under the name of "Sinclair's English cold- water soap" an article has been recently introduced which, accord- ing to accompanying directions, offers great advantages for laundry purposes, since it renders the use of soda and boiling of the clothes unnecessary, rubbing being required only for very dirty articles. The soap, it is claimed, saves fuel and washing material and the work can be done in one-third the time. The soap is dark yellow and has a slight odor of artificial oil of bitter almonds. Many contradictory analyses of this soap have been published, which may be partly due to the fact that such soaps are never manufactured alike even with the use of the same fats. One analysis shows the following constituents : — Alkaline sebate (actual soap) .... 62.7 per cent. Sodium carbonate ....... 1.3 Matter insoluble in alcohol . . . . .2.6 Water 32.4 " According to this, the constitution of this soap does not differ from that of ordinary soaps and its 'use offers not the slightest advantage, the wonderful properties claimed for it being fictitious. The soap is prepared by boiling 100 parts of fat (generally palm-oil) and 60 parts of resin to a stiff grain, and bringing the latter into frames of 12 to 13 cwt. capacity, where it is crutched until cold. Only when the grain is too stiff it is ground with solution of crystallized soda and a few per cent, of water-glass to render it more pliant. Imitations of Sinclair soaps are nearly all prepared by melting 100 parts of fat with 80 to 100 parts of resin and saponifying with caustic lye of 36° B. These soaps, however, are heavier and seldom successful, since the resin which remains unsaponified and sticky is perceptible in washing. Augmentation of curd-soaps. — An increase of the yield (about ten per cent.) of curd-soaps is obtained by grinding, the soap ab- sorbing water during this operation. The content of water in- corporated by grinding should, however, not exceed a certain limit, as otherwise the soap becomes too pasty and soft, or, as it is technically termed, " over-ground." 340 MANUFACTURE OF SOAP AND CANDLES. In many factories the yield of curd-soaps and resin curd- soaps boiled clear upon sub-lye is artificially increased by crutch- ing in substitutes, the operation being technically termed "filling" By this manipulation the soaps acquire a " dead" appearance, though their solidity and washing power are not injured to any great extent. For such an artificial increase of curd-soap, materials must, of course, be chosen which possess the property of not injuring the appearance of the soap too much and of not drying too quickly. As especially suitable filling materials, water-glass, soda, and talc are recommended and generally used either by themselves, or, better, in connection with each other. Water-glass by itself has the property of giving a good appearance to fresh soap and pro- tecting it from drying out too quickly, but by age the soap ac- quires a mean appearance and becomes hard as stone. An excel- lent filling material suitable for most curd-soaps is prepared by stirring 100 pounds of talc into 150 pounds of boiling water, then adding 30 pounds of crystallized soda, and gradually crutch- ing in 140 pounds of soda-water glass. The curd-soaps to be increased are best prepared from fats rich in stearin, such as tallow, palm-oil, fatty acids, etc. They are formed into a paste with the required quantity of lye, as pre- viously described, salted out, and evaporated to a stiff grain free from froth, which is thoroughly ground with water. Thorough saponification of the fats used is absolutely necessary, since, if the soap shows the slightest defect in this respect, it can be filled only slightly or not at all. When the grain is sufficiently ground and dissolved and shows good pressure while the sub-lye remains clear, the kettle is covered and allowed to stand for some time for the contents to settle. After the removal of the sub-lye and the soap being cooled to about 167° to 178° F., 30 to 40 pounds of the above filling material are crutched in for every 100 pounds of fat used. As the soap to be filled does not turn out always alike and therefore absorbs more or less filling material, it is ad- visable, in order not to expose an entire boiling to danger, first to test the absorbing capacity of the soap by a small sample. Good results in filling can only be obtained by great care and experience. Many soaps can be more readily and better filled by HARD SOAPS. 341 using the filling material in a warm state, while others better ab- sorb cold filling. The operation itself can be executed in the kettle after the removal of the sub-lye or in a suitable vessel. In the same manner as tallow and palm-oil curd-soaps, resin curd-soaps prepared from the same materials with 30 per cent, of resin can be filled to the extent of about 30 per cent. The filled soaps are brought into smaller frames than those employed for curd -soap, and, after cooling, cut and dried for some time, whereby they gain in solidity. They are then cut into square pieces, pressed, and brought into commerce. b. Card-Soaps upon a Precipitate of Paste. The fabrication of smooth curd-soaps, which are found so much in commerce at the present time, is effected by two different methods, according to the fats used. The object of both methods is to produce as pure a soap as possible by separating all the im- purities with the superfluous content of water and alkali. One method is to grind by means of water curd-soaps boiled upon sub-lye until a paste is formed, and is used for all soaps from animal fats, olive-oil, palm-oil, and oleic acid. The other method is based upon the formation of a precipitate of paste, which is produced by adding either lye or salt in excess, though in both cases not sufficient to effect a separation of the soap. This method is only applicable when working cocoanut-oil or palm-kernel oil in connection Avith other fats, and can be exe- cuted either in a direct or indirect way. As in the fabrication of other soaps, the soap-boiler must here be guided by the nature of the fats to be used and the arrange- ment of the factory. What he has to attain is a pure soap free from froth and stains and thoroughly settled with as little precipitate of paste as possible, and, further, an utmost yield of good sal- able soap from the fats used. This is not an easy task, and re- quires quick observation and a thorough knowledge of the nature of fats. With the frequent fluctuations in the fat and oil trade it is no longer possible to work according to one established rou- tine, and the production of a uniformly beautiful product an- swering all the above demands is difficult. 342 MANUFACTURE OF SOAP AND CANDLES. The large number of smooth curd-soaps brought into com- merce renders it impossible to treat of them collectively. Special attention has to be paid to all possible contingencies, and hence the fabrication of smooth soaps from various combinations of fat must be described in such a manner as to render this volume use- ful for other times than the present, and serve, especially the younger soap-boiler, as a guide in carrying on his business. All wax-soaps should be free from dirt and be lustrous, and hence fats free from impurities or previously clarified are chosen for their fabrication. Sometimes even this is not sufficient, and defects have to be remedied by the manner of boiling, which is frequently effected by first boiling the lardaceous or all the added fats to grain. Direct boiling is, however, the method most gen- erally used, it having the advantage of being quicker, though it is doubtful whether it is always cheaper. By direct boiling the entire operation is finished in a few hours, and as but very little lye is separated, only a small quantity of common salt is required. Furthermore, the consumption of fuel is small, as in working with strong lyes the heat developed during the combination of the fats with the alkalies is frequently so great as to render after-firing unnecessary. These points are in favor of direct boiling. If, however, on the other hand, the added fats are first boiled to grain, the boiling process, even with the use of two kettles, lasts much longer, and more lye, more salt, and more fuel are used ; but the fact that the consumption of more lye re- quires also more alkali would prove that in many cases better results and a larger yield are obtained than by direct boiling. Every soap-boiler knows that the yield depends less on the fats used than on the lyes. By boiling with caustic lye of from 28° to 30° B. it can be shown by calculation that for the saponifica- tion of 100 pounds of fat about 17 pounds of caustic soda of 66 per cent, are required, but with lyes of 14° to 15° B. at least 20 pounds. Even if a portion of the caustic soda passes into the sub-lye, the whole of the excess is not lost, but lies in the in- creased soap. While with strong lye a yield of 150 per cent, is scarcely obtained from the best fats, with weak lye a yield of 160 to 165 per cent, is of ordinary occurrence. Hence soaps boiled upon a precipitate of paste are the more firm and dry the HARD SOAPS. 343 stronger the lye used for boiling, while most soaps boiled by the indirect method only acquire such firmness by after-drying. Though what has been said does not prove the absolute necessity of indirect boiling, it is indispensable for all fats requiring weak lye for their correct saponification, the principal ones of these being all those of animal origin. Oleic acid should also be first boiled to grain, since good olein soaps from oleic acid alone can only be prepared by repeated and long-continued boiling. Direct boiling is best when much cocoanut or palm-kernel oil is used in connection with such light oils as cotton-seed or linseed- oil, because the process of boiling proceeds with greater regularity and the resulting product shows greater solidity. Indirect boil- ing becomes, however, absolutely necessary when the quantity of supplementary fats used is larger than that of the combining fats, and also when they consist of mixed fats, as, for instance :— Tallow . . . Cotton-seed oil Peanut-oil . Palm-kernel or cocoanut-oil 400 pounds. 300 300 500 " Such a formula can, of course, be directly boiled, but while the resulting soap will show a firm cut surface and have a bright and clear appearance while warm, it will not improve by storing, but become dull and finally entirely lose the silvery flux. On the other hand, by indirect- treatment the resulting soap will be mod- erately firm, of a better appearance, and improve by age. Supplementary fats (tallow, cotton-seed oil, etc.) being cheaper at the present time than cocoanut-oil or palm-kernel oil, such a combination as the above is of ordinary occurrence. The softer fats are also frequently replaced by lard, horse-fat, and bone-fat, and even by oleic acid or bleached linseed-oil, the use of the latter being by no means objectionable, since the resulting soap is soft to the touch, yields a strong lather, and possesses good detergent properties. A too large addition of it must, however, be avoided, as otherwise the soaps acquire a bad odor. Indirect boiling being the most advantageous with the above formula, the process is as follows : — The fats are boiled either with tank-lye of 12° to 14° B., or with caustic soda lye of 10° to 13° B., 220 to 250 pounds of 344 MANUFACTURE OF SOAP AND CANDLES. such lye being required for the complete saponification of 100 pounds of fat and for obtaining the utmost yield. The tallow and other fats, except the palm-kernel or cocoanut- oil, having been brought into the kettle, one-eighth of the quan- tity of lye required is added and a moderate fire started. If combination does not take place immediately after ebullition, stronger boiling is of no use. The defect is remedied by adding some cuttings of the same kind of soap, or waiting with the furnace door open until combination takes place. Lye is then gradually added until a clear paste free from froth is formed. The addition of the correct proportion of lye is recognized by a grain-like separation of the soap. Water is then added until combination and paste become again apparent. If the soap is, however, still viscid and shows no taste of lye, lye is wanting. If one is sure of having added the required quantity of lye, some stronger lye, of about 15° B., is added and boiling continued until the clear soap breaks into regular roses.* Salting out is now proceeded with, 5 to 6 per cent, of common salt being suffi- cient for the purpose. It is recommended to soak the salt in Avater and add it, with the furnace door open or steam shut off, by scattering it successively over the soap. Generally the grain rises up at once and the whole is then boiled once more until laminae are formed and the lye runs off clear. With the use of good, pure fats the lye settles completely in two hours, when it is removed and the necessary quantity of lye for boiling the cocoanut and palm-kernel oils is brought into the kettle, about 600 pounds of caustic lye of 20° B. being required for the above quantity of 500 pounds of oil. After boiling the grain in the kettle with this lye, some soap-cuttings are added, and, when all is dissolved, the oil (400 pounds of palm-kernel oil and 100 pounds of cocoanut-oil can be recommended) is grad- ually introduced. If the soap, after the addition of the last por- tion of cocoanut-oil, should be viscid or glassy, strong salt water is carefully added until the soap breaks uniformly into roses. This addition of salt water is, however, not necessary if, as is fre- * The thickening soap on the place where the steam from below forces its way through resembles an expanding rose. HARD SOAPS. 345 quently the case, the grain holds salt lye fixed. Such finished ground-soap should not show any touch of sharpness and must be evaporated until it begins to puff like soap containing little water. Salt soaked in water is then gradually added, 6 to 8 per cent, of the palm-kernel and cocoanut-oils used being frequently suffi- cient. The soap now becomes thinner and feels moist to the touch. If it yields any lye, separation has been carried too far, but this defect can be remedied by supplementary grinding with water. It is a good sign when, after the soap ceases to boil and remains covered for a few minutes, a bright grain lies in the kettle. The appearance of white or dull soap when scraping the surface with a crutch indicates that separation has been carried too far ; it is remedied with water. Separation not carried far enough is, as a rule, not a defect. If in ladling out it is observed that there is too much paste in the kettle, some strong salt water may be added by allowing it to run down the sides of the kettle, and the grain separated thereby is mixed with the soap in the frames. We would here remark that the quantity of lye prescribed (600 pounds of 20° B.) is, as a rule, too small for the saponifica- tion of 500 pounds of palm-kernel and c'ocoanut-oil, and, hence, it may happen that it is not enough or just sufficient, this depend- ing entirely on the condition of the grain. If, on the one hand, the grain is oversaturated with strengthening lye, it will subse- quently yield lye, and if, on the other, there is too little lye or just sufficient, the after-effect is shown in boiling for combina- tion. Now as lye can be readily added, but a preponderance of it only be reduced by increasing the quantity of fat, it is better to prescribe too little than too much for these soaps. The same holds good as regards the quantity of lye prescribed for the preparatory boiling to grain. The statements of areo- meters differ, and hence it may happen that though caustic soda lye of 10° to 13° B. is used, 280 to 300 pounds of it might nevertheless be required. Prime white curd-soap (wax-soap). — This is one of the prin- cipal soaps which is best boiled upon a precipitate of paste. It can also be prepared by incompletely salting out a paste boiled largely from palm-kernel oil or cocoanut-oil, but the result is 346 MANUFACTURE OF SOAP AND CANDLES. generally not satisfactory, especially when using animal fats in connection with them, and a uniformly good product can only be* obtained by a correspondingly correct manner of boiling. As a fine quality of soap can, however, be manufactured by the last- mentioned method from palm-kernel oil and oleic acid, we give the process, which is as follows : — Lye of 20° to 23° B. prepared by treating 95 per cent, soda with 50 per cent, of lime, and a combination of one-third to two- fifths of pale oleic acid and two-thirds to three-fifths of palm- kernel oil are used. As tank-lye of the above strength contains much carbonate, it is best first to paste the palm-kernel oil to a strong touch and add at once some salt to prevent thickening. The oleic acid is then gradually brought into the kettle, a mod- erate fire being kept up, and after again fitting the paste to a per- ceptible touch, it is allowed to boil until the froth disappears, which will require only a short time. The paste which is per- fectly clear, and boils black and bright without rising much, is thoroughly saturated, the fats being completely saponified and the alkaline carbonate of the lye having also entered the combi- nation. Boiling is then finished by gradually adding with con- stant stirring some moistened salt until the paste " wets" per- ceptibly without lye draining off. In case the paste has been salted out too strongly, it is ground with some water, and then, after removing the fire, is allowed to stand a few hours in the well-covered kettle. When the lid is removed the soap in the kettle will be found to be of a honey-yellow color, free from froth and liquid, and ready for framing. With correct salting out a thin layer of black, liquid paste, which contains but little soap, is found between the soap and sub-lye, which is boiled and salted out with the sub-lye. If, however, a stronger precipitate of paste is found, some grain can be obtained by careful after- salting, which is crutched into the soap in the frames. With some experience uniformly good results can be attained in this simple manner without much residue of grain-paste. It is not difficult to obtain nearly the entire yield, about 140 per cent., from the fats in salable, pure white soap, as the thin paste floating upon the lye contains, with a correct execution of the work, only the marble-forming dirt. This process is, however, HARD SOAPS. 347 only available for the above combination, the result being not nearly so uniform by replacing the oleic acid by cotton-seed oil, tallow, or lardaceous fats. By the direct method smooth white curd-soap is most readily prepared from palm-kernel oil. As soap from the pure oil is, however, very brittle and lean, it is best to use a combination of two-thirds to three-fourths palm-kernel oil and one-third to one- fourth of soft or liquid fats in order to make the soap more deli- cate and pliant, cotton-seed oil, oleic acid, lard, and peanut-oil being most suitable for the purpose. The following may serve for a formula : Palm-kernel oil 1000 pounds, cotton-seed oil 250, lardaceous fats 250. For pure white soap the cotton-seed oil requires bleaching. For this purpose it is heated to 113° F. Dissolve for every 100 pounds of oil J pound of potassium bichromate in 1J pounds of boiling water, add to the solution If to 2 pounds of hydro- chloric acid, and pour the mixture with vigorous crutching into the oil to be bleached. After remaining in contact with the bleaching liquid for about a quarter of an hour the mass assumes a bluish-green color. When a sample is dropped upon a glass plate, a dark-green precipitate is at once recognized, from which, after standing a short time, the oil runs off entirely colorless. After standing for one hour the clear oil is drawn off and at once used for saponification. The lye for boiling smooth white curd-soap by the direct method is best prepared from pure, high-graded caustic soda, or by increasing the strength of good tank-lye of 15° to 18° B. with caustic soda to 30° B. As lye of this strength requires great care in effecting the combination, it is best first to bring the entire quantity of palm-kernel oil into the kettle, and after intro- ducing combination with one-half the quantity of lye required (about 500 pounds) gradually add the remainder until saponifi- cation to a good touch is effected and the soap again boils thin. By now adding with a moderate fire the cotton-seed oil and other fats, which combine readily on account of the saponification already introduced, a thick and curly-boiling soap is soon formed, which is reduced to normal boiling by fitting with strong lye or lye containing salt. The soap is then fitted to a strong touch 348 MANUFACTURE OF SOAP AND CANDLES. until it boils perceptibly thinner, when it is somewhat evaporated and then shortened with moistened salt until, when thrown with the spatula, it nutters and bubbles. It is finished when a sample cooled upon the spatula feels moist. Soap prepared with lye of such strength and correctly treated will never show froth, the appearance of the latter being generally due to the use of too weak lye. In shortening the salt must be added carefully, ob- serving the effect produced by one portion before adding the next. Soap too strongly separated frequently shows gray stains. As regards the framing of this soap, it is best to ladle out small boilings after remaining at rest for one or two hours, in order to give the paste time to subside somewhat, and keep the soap in the well-covered frame for 24 hours. Boilings of 6000 pounds and over may be left in the kettle over night, any froth or cold foliated coating being removed before ladling out to prevent any cold soap from reaching the frame. If the fats used are melted by steam or otherwise thoroughly purified, it is not necessary to pour the soap through a sieve ; but where there is any danger of injuring the quality by impurities, bark, or wood from the barrels, it is best to use this precaution. Soap thus prepared lies dark in the frame, but is clear as honey, and after remaining covered for 24 hours, and when suffi- ciently cooled off, is generally pure to the bottom and ready to be brought into commerce. Soaps prepared according to this process are sufficiently firm and at the same time delicate and pliant, and by storing acquire a beautiful white color. The yield is about 120 pounds of prime curd-soap from 100 pounds of fat used. The paste is best boiled out with pale oleic acid, and the resulting grain used for the same kind of soap or for a second quality. In summer it is advisable to use less cotton-seed oil and more palm- kernel oil. The process of boiling with direct steam differing somewhat from the preceding will be described separately. Boiling smooth ivhite curd-soap with the use of direct steam. — Animal tallow always has been and is still at the present the best material for household soaps, and though pure tallow curd-soaps are now but little used for laundry purposes, tallow is neverthe- less the material which gives to all soaps a certain solidity and HARD SOAPS. 349 high ecoDomical value. For this reason it is the more valuable for smooth white soaps, as the product obtained is, independent of its white color, of excellent quality and yields the largest re- turn. The materials originally used by Groodhaus, of Darmstadt, were tallow and cocoanut-oil, for which, however, with increasing competition, all possible fats and oils were substituted, so that in 1882 and 1883, when good animal fats were very scarce and dear, even linseed-oil was used. By the extension of the manu- facture of half-boiled soap from 1860 to 1870, the spoiling of many boilings gave to the soap-boiler useful hints for the manufacture of smooth white soaps, so that the general introduction of these soaps into commerce may be dated from that time. The production of a beautiful white soap is much facilitated by the use of steam, but as fluctuations in the price of fats and oils will frequently necessitate a change in the combination of the fats used, suitable measures as regards the employment of steam have to be taken. We give in the following a few formulas which, on account of their composition, are likely to give uniformly good products. Parts. "Parts. Parts. Parts. Tallow free from dirt Palm-kernel oil Cotton-seed oil . . . . 10 6-7 1 10 10 2 10 15 3 10 20 5 The more cotton-seed oil is used the greater the necessity of its being first bleached. Bleached linseed-oil, white oleic acid, or double the quantity of lardaceous fats may be substituted for cotton -seed oil. We would here remark that in 1877 and 1878, when American lard was very cheap in Europe, large lots of it were frequently used, especially for white curd-soaps, and it can be confidently asserted that the product brought into the market during this time was the finest ever seen. Should the kettle not be large enough to work the entire quan- tity of fat at one time, it is necessary first to saponify the tallow and cotton-seed oil, for which lye of less strength may be used. With a large percentage of palm-kernel oil it is, however, better 350 MANUFACTURE OF SOAP AND CANDLES. to bring it also into the kettle and use stronger lye. For instance, 2000 pounds of tallow, 1000 pounds of palm-kernel oil, and 300 to 500 pounds of cotton-seed oil are pasted, in order to prevent in salting out any strength from passing into the sub-lye, either so as to be perfectly neutral or show only a moderate touch. By the admission of steam through a perforated pipe on the bottom of the kettle, and simultaneous use of an open fire, saponification takes place very rapidly. In order to prevent thickening it is advisable to compound the lye, especially when strengthened with caustic soda, with some salt, or scatter the latter, after combina- tion is complete, over the surface of the contents of the kettle, this being absolutely necessary with the use of much palm-kernel oil. Salting out is commenced as soon as the paste is clear and shows no perceptible touch, and is continued until the lye runs oif clear. Special measures for safety are not required with the use of much palm-kernel oil, and besides, boiling over can be readily prevented by shutting off the steam. The paste separates without perceptible heating in the grain or sub-lye, and after boiling for some time the steam is shut off and the fire removed and the kettle allowed to remain at rest for a few hours. The open fire is necessary so that in salting out none of the salt will remain ineffective and undissolved on the bottom of the kettle. After removing the sub-lye and combining the remaining 2000 pounds of palm-kernel oil with about 1000 pounds of lye of 26° B., another 1000 pounds of the same lye are gradually added until a slight touch is perceptible, when the paste is then again salted out. Clear boiling of the paste upon the sub-lye in the kettle is then commenced, which, however, can only be done over an open fire, since the condensed water of the steam would render the process more difficult. In doing this care should be had that the lye retains some strength. The less sub-lye there is, and the stronger it is, the quicker the froth is thrown off. The soap must not, however, to prevent scorching, be boiled dry. When the grain is free from froth and large-grained, soap-cuttings are added, which are allowed to dissolve^ the kettle being covered in the mean while. The fire is then withdrawn, and after allowing the soap HARD SOAPS. 351 to remain at rest for a short time, the under-lye is again drawn off or pumped out and any light froth upon the grain removed. The operation of grinding is now commenced, and is carried on with high-pressure steam of about three and a half to four atmospheres. As soon as the steam is admitted hot water is quickly poured over the soap while a workman promotes the operation by vigorous crutching. When the mass begins to form a uniform thin paste, which runs from the spatula without showing dry spots, and which in throwing flutters and bubbles, the soap is finished. After boiling the soap through once more, the steam is shut off and the well-covered kettle allowed to stand quietly for 24 hours. In bringing the soap into the frames the same rules as previously given for soap boiled by the direct method are ob- served. The better the operation of grinding has been executed the more delicate, whiter, and more homogeneous the grain will be, but also the smaller the yield of prime soap. The grain re- sulting from salting out the paste remaining in the kettles is used with the next boiling. Second quality of smooth white curd-soap. —Frequently a second quality of smooth white curd-soap is boiled from the precipitate of paste from the prime quality, which is best effected by boiling the precipitate with cotton-seed oil or pale oleic acid, allowing about 100 parts of oil to 300 parts of fatty contents of the pre- cipitate. The paste formed is fitted to a slight caustic taste and then slightly salted out so that a complete separation is not effected. After allowing the soap to rest for a short time, it is ladled into the frames while hot. The small residue of precipi- tate is used for resin-soaps. The soap thus obtained is somewhat darker and generally less pure than the prime quality. Smooth curd-soaps with resin. — For several years a large de- mand has sprung up for smooth curd-soaps with resin, so that in some regions they have superseded almost all other kinds of soap for household purposes. The manufacture of this soap has been materially facilitated by the introduction of high-grade caustic soda, which permits the production of a lye excellently adapted for the most rational process of boiling by strengthening tank- lyes. Though the combination of fats used, which consists chiefly of palm-kernel oil, requires strong lyes, this is still more 352 MANUFACTURE OF SOAP AND CANDLES.* the case for the saponification of the resin. The non-observation of this leads readily to such frothy and badly-settled soaps as are only too frequently found in the market. The best soaps of this kind are those which were formerly pre- pared by the direct method from pure palm-kernel oil, with a small addition of cocoanut-oil and 10 to 15 per cent, of pale, transparent resin, combined with caustic soda lye of 27° to 28° B. To 1000 pounds of palm-kernel and cocoanut-oil and 150 pounds of pale, transparent resin, were added 700 pounds of caustic soda lye of 27° to 28° B. After dissolving pure cuttings of the same soap in the mass, 1000 pounds of oil were gradually added. On account of the strong lye a thick and curly but sharp soap was formed, but as soon as the resin and the required quantity of the remaining lye were added, the soap boiled more easily. The finished soaps were pale yellow and possessed considerable deter- gent properties. The necessary corrections were only made when everything boiled uniformly in the kettle, and were generally limited to the addition of a few bucketfuls of weak salt lye to the thick soap. Soaps like the above are still made at the present time, but since tallow and lardaceous fats, cotton-seed oil, etc., are cheaper than palm-kernel oil, other combinations are made which require a different process of boiling. With only 10 to 15 per cent, of resin one may even venture to take one-half combining fats and one-half other fats. A formula of 100 to 150 pounds of resin, 300 pounds of tallow, 200 pounds of cotton-seed oil, 400 pounds of palm -kernel oil, and 100 pounds of cocoanut-oil gives a fair quality of soap. This combination can also be advantageously worked by direct boiling, since the resin effects the combination and easy boiling. The process is the same as for the preceding, except that lye about 1 degree weaker is used. The formula can also be treated indirectly by first boiling the tallow to grain, and it will be found that when this grain is thoroughly boiled and finally brought into the kettle, the soap acquires a beautiful appearance, which is still improved by storing. HARD SOAPS. 353 Oranienburg curd-soap. — The so-called Oranienburg curd-soap is a smooth resin curd-soap. It being generally demanded of a light, clear color, the palest kinds of French or American resin only can be used, and only fats which yield clear white soaps, such as white palm-kernel oil, tallow, cotton-seed oil, white oleic acid, lard or lardaceous fats, light bone-fat, and, if the state of the fat and oil market allows, some bleached linseed-oil. It is advisable to use at least two-thirds palm-kernel oil and one-third of the above fats. In winter it is especially necessary to work at least one-third tallow, bone-fat, or lardaceous fats, as soaps from pure palm-kernel oil or boiled in connection with a little cotton-seed oil are inclined to mould. The following are suitable formulae : — For ivinter : White palm-kernel oil, 600 pounds ; tallow or pale bone-fat, 200 ; cotton-seed oil, linseed-oil, or pale oleic acid, 100 ; pale resin, 180 to 225 (or 20 to 25 per cent, of the fat used). For summer: White palm-kernel oil, 700 pounds; tallow, lard, or bone-fat, 100 ; cotton-seed oil, linseed-oil, or oleic acid, 100 ; pale resin, 180 to 225. Small deviations from the above prompted by the state of the market exert, of course, no great influence upon the result. All waste, especially the same soap, resulting from salting out the precipitate of paste from a previous boiling, is brought into the kettle and boiled upon lye of at least 29° to 30° B. until all froth has disappeared, the quantity of lye required being about one-half of that of the fats to be used. The palm-kernel oil is then carefully introduced, the comminuted resin being held in readiness to promote combination, which generally takes place immediately after the addition of one-half of the resin. This also prevents the mass from rising too violently, lye being also held in readiness for the latter purpose. The greatest care is always required in combining fats with such strong lye. Combination being induced and the mass boiling quietly and uni- formly, the quantity of lye still wanting and the rest of the fats are gradually introduced until the soap boils thick and curly, but shows a perceptible touch. With a moderate fire, the rest of the resin is then allowed to dissolve and the mass again fitted to a good caustic taste. With an average lye of 30° B. the soap will now 23 354 MANUFACTURE OF SOAP AND CANDLES. scarcely boil too thick, because the more resin is worked in the thinner the soap becomes and the stronger must be the lye re- quired towards the end of the operation. A slight excess of lye, perceptible upon the tongue or by dull, turbid streaks upon the spatula, suffices for the separation of a precipitate of paste. If, however, the soap should boil somewhat too thick and heavy, a few bucketfuls of water, weak lye, or salt water suffice to render it more loose and thinner. Light, loose boiling is an indication of the soap being finished. The fire is now removed, the kettle covered for a few hours, and the soap finally framed while hot. The frames remain covered for two days for the paste to settle. The soap being ladled into the frames, but a small quantity of paste remains in the kettle, which, when boiled with oleic acid or bone-fat and salted out, yields very little sub-lye. The more viscid and fatter such precipitate of paste is — which is attained by avoiding salt as much as possible and not fitting too fine — the more can one count on a good settling in the frames. Such pre- cipitate of paste, when cold, can be drawn like leather from the curd-soap adhering to it, which is pure and salable close to the precipitate. Soap boiled according to the above- described process will never show froth, as its formation is prevented by the use of sufficiently strong lye. Hence it is far better to be obliged to add some water or weak lye towards the end of the boiling than to have to evaporate perhaps for hours, which, besides, does not always pre- vent the formation of froth. This method offers the further ad- vantage of not having to drag large quantities of precipitate of paste from one boiling to the other, as is so frequently the case even in factories manufacturing large quantities of these soaps. And, besides, large boilings can be faultlessly finished in a com- paratively short time over an open fire without the use of steam. All soaps largely boiled from palm-kernel oil have a viscid but beautiful and lustrous formation of grain-fibre, and can only be regularly divided by a- well-constructed cutting machine. The yield, inclusive of the curd-soap recovered from the pre- cipitate, and counting the resin as fat, is about 150 per cent., which could be increased by the use of larger proportions of tallow, palm-oil, or good lardaceous fats, and might turn out HARD SOAPS. 355 somewhat less with the use of more liquid vegetable fats, such as linseed and cotton-seed oils. Yellow resin curd-soap. — Yellow resin curd-soap, also called palm-kernel oil soap or yellow curd-soap, is prepared in the same manner as the preceding, with the exception that the soap is col- ored with 5 to 15 per cent, of crude palm-oil, according to the demand of customers. Where a dark color is not objectionable, larger quantities of dark fats, especially bone-fat, can be worked in ; it being, however, advisable in this case first to boil the bone- fat to grain in order to purify it and modify its odor. A higher percentage of resin is also generally used. In fact, the soap is found in so many shades as to render it difficult to recommend any formula, since the soap-boiler has to be guided by the de- mands of his customers. Care must, however, be had not to use too much crude palm-oil, as the yellow lather caused by it would give rise to complaints. More than 12 to 15 per cent, of the fat used is decidedly objectionable, 5 to 10 per cent, being generally sufficient. 356 MANUFACTURE OF SOAP AND CANDLES. CHAPTER XIII. HARD SOAPS (CONTINUED). II. Paste-Soaps. Under paste-soaps we understand products which, when fin- ished and in a hot state, have the appearance of clear solutions of paste, but when cold form moderately firm soaps. It is always a good sign when the finished soap shows a slight froth, which in the covered kettle decreases to a thin film. In pouring out the soap more froth is generally formed, which cannot be prevented, and, besides, is not injurious, since the soap, if kept at a tempera- ture of 167° F., purifies itself by expelling all foreign substances. The toilet-soaps known as glycerin-soaps, as well as the cheaper cocoanut-oil soaps, also belong to this class. They will, however, be described later on, since, being perfumed and colored, they are not intended for laundry use. Soaps intended for the latter pur- pose can only be colored without injury by such old-established coloring substances as Frankfort black, ultramarine, and bole. Yellow and brown, being also favorite colors for household soaps, are obtained by the fats and resin. For yellow, crude palm-oil and 5 to 10 per cent, of resin suffice, while for brown, the same materials intensified by some sugar color are used in case no fats giving the required coloration, such as wool fat, fuller's fat, or brown fats, are employed. As regards their external appearance paste-soaps may be divided into two groups : smooth and marbled soaps. In respect to their other properties nothing definite can be said, since there are so many varieties that their number cannot even be approxi- mately determined, the differences depending on the yield, which may vary from 250 to 1600 per cent, and on the fats used. All these soaps can be prepared by the direct method by the use of weak lye. Their manufacture is, however, rendered en- HARD SOAPS. 357 ti rely safe by always treating the base-soaps as curd-soaps and augmenting them to the greatest yields by means of salt, etc. The soap-boiler who uses caustic lye at discretion can never fore- tell the yield he Avill obtain from the finished soap. For the manufacture of paste-soap with a large yield, the use of double the quantity of caustic lye required for the complete saponification of the fats signifies nothing, because as soon as aug- mentation exceeds 260 per cent, caustic lye has to be added in order to obtain soap of sufficient hardness on the cut surface. It is. different, however, with soaps of a low yield, which are to resemble curd -soaps or at least half-grain soaps. This can be effected by taking only as much caustic lye as is required for the saponification of the fats and using the materials for augmenta- tion in as concentrated a form as possible. Three kinds of augmenting materials are generally used : (1) Lyes containing carbonates and common salt, which is the easiest way of preparing paste-soap, (2) water-glass, and (3) flour, talc, clay, cryolite, each by itself, or in connection with solution of common salt, lye containing carbonate, or water-glass. Paste-soaps with a yield of 250 to 275 per cent — Paste-soap to be an imitation of curd-soap must resemble it in its principal properties, dry out but little, and be economical in use, the at- tainment of which depends partially on the fats used and par- tially on the filling material. The best smooth white or colored soaps, which, if desired, can be artificially marbled, give a yield of about 275 per cent. The following may serve as a formula for such soap : — 100 pounds of cocoanut-oil, 50 ti tallow, 75 a caustic soda lye of 36° B., 60 (< water-glass, mixed with 45 ti tank -lye of 12© B., 5 it common salt, dissolved in 20 a ""water, 60 u tank-lye of 5° B. The process is as follows : — The tallow and cocoanut-oil melted and heated to 189.5° F. are stirred together with the 60 pounds of tank-lye of 5° B., 358 MANUFACTURE OF SOAP AND CANDLES. previously mixed with about 40 pounds of the caustic soda lye of 36° B. As soon as combination is effected the remaining 35 pounds of the caustic soda lye are added. When the combina- tion forms a solid soap, and the latter, which is kept at a tem- perature of from 189.5° to 201° F., shows an inclination to thicken, the salt water is added. Even an actual thickening would signify but little, and would be a sure sign of the estab- lishment of an actual combination between the fats and the lye. In order to remedy this defect the soap should be kept right hot and crutched until the pieces are dissolved. When this is the case the water-glass mixed with lve is added. After again crufcching for some time the kettle is covered and samples are taken later on. If the samples prove not sufficiently solid, caustic lye has to be added in summer, and in winter a solution of about three pounds of common salt in water. A correct fit is readily effected and learned by a few experiments. Soaps thus prepared keep very well if not hardened too much either by means of salt water or caustic lye, and they will never petrify in consequence of the water-glass they contain. By substituting for the 60 pounds of water glass in the above formula 30 pounds of water-glass and 40 pounds of talc, the pro- portions of salt and lye remain the same, but the execution of the process varies somewhat. The 40 pounds of talc are crutched into the hot fats, and after effecting saponification in the same manner as above with 60 pounds of tank-lye of 5° B. and 75 pounds of caustic soda lye of 36° B. and combination is estab- lished, the 25 pounds of salt water are added, and finally the 30 pounds of water-glass mixed with 25 pounds of tank-lye of 12° B. After testing the finished soap is treated in the same manner as the preceding. The formula may also be changed by substituting palm-kernel oil for a portion of the cocoanut-oil, or by using palm-kernel oil alone. As long as more cocoanut-oil is used than any other fat, for instance, 60 pounds cocoanut-oil, 40 pounds palm-kernel oil, and 50 pounds tallow, the proportions of lye and salt may re- main the same, though great care must be had in fitting. If, however, the quantity of cocoanut-oil is less than half of that of palm -kernel oil, the strength of the caustic lyes should be less HARD SOAPS. 359 by 1 to 1J° B. With the use of palm-kernel oil alone it is ad- visable to change the formula to 110 pounds of palm-kernel oil and 40 pounds of tallow and caustic soda lye of 35° B. instead of 36° B. For tallow may also be advantageously substituted other fats containing stearin, especially crude or bleached palm-oil. With the use of sedimentary oils from oil-reservoirs, or cotton-seed oil or peanut-oil, the resulting soaps though serviceable are less solid. Soaps of an equally good quality as the preceding are those brought into commerce under the name of yellow soap, or filled resin-soap, with a yield of 275 per cent. The formula differs from the preceding one in so far that it consists of more or less cocoanut-oil, palm-kernel oil, crude palm- oil, and resin. Such a formula, for instance, would consist of :- — 90 pounds of cocoanut-oil, 10 " crude palm-oil, 20 " dark resin, 60 " caustic soda lye of 36° B., mixed with 40 " tank-lye of 3° B., 40 " water-glass, mixed with 10 " caustic lye of 30° B., 2 u common salt, dissolved in 10 " water. The process is apparent from the formula itself. After melt- ing the fats and the resin, the 60 pounds of caustic lye of 36° B. and the 40 pounds of tank-lye of 3° B. are crutch ed in, and a good combination being established the salt water is added and finally the water-glass. The soap does not require boiling, but must be kept at a temperature of above 189.5° F. Small samples of the finished soap must be firm and hard; if other- wise, fitting is wanting, and the defect is remedied by adding a few pounds of caustic lye of 36° B. and again heating until all is thoroughly combined. Too much sharpness must, however, be avoided, since this would frequently result in stained soaps. This variety of soaps also embraces all other soaps with a yield of about 250 per cent, and which, though the finished product shows all the characteristics of a grain or half-grain 360 MANUFACTURE OF SOAP AND CANDLES. soap, are formed into smooth soaps partially by the method of their augmentation and partially by the manner of their framing. The base-soap for these soaps is also either a grain or half-grain soap to which are added as condensed solutions as possible. The principal condition for such soaps is that with a correct and moderate fit the fats used should yield a product dry and solid on a cut surface. A very solid grain-soap can, for instance, be boiled from bone-fat by using much salt and thoroughly evaporating, but by augmenting such soap the yield would not exceed 170 to 180 per cent., as the soap would either break up or become too soft. Such fats used by themselves are not suitable for filled soaps. Tallow or bleached palm-oil are better adapted for the purpose, and 10 to 20 per cent, of resin can without in- jury be added to such soaps. Green sulphur-oil (olive-oil ex- tracted from the press-residue) gives also a firm grain-soap which can be subsequently augmented. The above-mentioned three varieties of fats are the only ones, which boiled, either by themselves or in connection with each other, yield grain-soaps allowing of a regular and paying aug- mentation. The preparatory boiling to grain may be executed in the customary manner, provided the final result be a solid, lean soap, the other properties of the grain, whether it be dull or sharp, contributing nothing to the successful filling of such soaps with lyes containing carbonate and common salt. Solution of carbonate of 10° to 12° B. heated to from 167° to 189.5° F. can be either crutched into such grain-soaps or the whole may be allowed to boil up and the paste formed hardened with salt water. The result is a genuine filled soap and the yield can be considerably increased. It is, however, different if filling agents such as water-glass and talc are to be used. The base-soap must then be as neutral as possible, which can only be attained by the grain showing good saponification and being subsequently ground until any excess of sharpness has subsided. Water-glass of 50° B. can be simply crutched into correctly prepared base-soaps of this kind, and with a yield of 250 per cent, they will remain thick-ribbed similar to grain-soap. There being a difference in the various kinds of water-glass, it may be HARD SOAPS. 361 sometimes necessary to assist with filling material containing more water, talc mixed with water or simply hot water being frequently added if the soap with a yield of 250 per cent, is very thick. Should the base-soap not take up the water-glass, i. e., tear so as to appear as if salted out, the cause of this defect may be due to the base-soap containing too much water, salt, and lye, or to the water-glass itself, it being extremely difficult even for the most expert soap-boiler to form a correct judgment. It is well known that water-glass rich in silicic acid contracts every kind of grain-soap, and only forms paste-soap which will draw threads when the yield reaches 290 per cent., and then augmentation can be extended to about 340 per cent. On the other hand, with weak water-glass containing little silicic acid, for instance, water- glass diluted to 20° B., the same good grain-soap would in many cases completely salt out with a yield of 200 per cent. Hence, if a grain-soap contains from the start much fixed water, which in this case even holds salt and soda in solution, the base-soap will not fill but separate. What is a defect in good grain-soaps becomes, however, a ne- cessity in other grain-soaps boiled from 'tallow in connection with cocoanut-oil or palm-kernel oil. Grain-soap made with 50 per cent, of cocoanut-oil can seldom be filled with strong water-glass alone, an addition of salt water, soda solution, or even caustic lye being generally necessary. Moreover, every soap requiring salt or lye in filling with water-glass in order to preserve the latter intact, becomes rough and hard in drying. To avoid such addi- tions it is only necessary to add pure water or dilute solutions of water-glass as may be necessary, the required salts being then spontaneously formed. Talloiv soda-soap. — The soap known under this name is gene- rally of a brilliant white color. It is poured into small low frames, curly flowers being drawn into the surface with a rod. It is generally prepared from two-thirds palm-kernel or cocoanut- oil and one-third tallow, and filled with solution of carbonate of soda or with water-glass. The best qualities are prepared from two-thirds tallow and one-third cocoanut-oil and a vield of 200 362 MANUFACTURE OF SOAP AND CANDLES. to 220 per cent., while that of the poorer varieties is 300 per cent. The soaps can be boiled by the direct method, as is frequently done for convenience sake. To obtain the best quality possible, it is, however, advisable first to boil the tallow and also a portion of the other fats to grain so that the finished soap will resemble a filled grain-soap rather than a paste-soap. The following may serve as a formula for tallow soda-soap by the direct method : Palm-kernel oil 100 pounds, tallow 50 pounds, caustic soda lye of 35° B. 80 pounds, potash solution of 25° B. 100 pounds, salt water of 20° B. 50 pounds. The fats are melted and passed through a fine sieve, it being also necessary to purify the lye and salt water in the same manner and to scour the kettle bright, as the soaps with a yield of 250 per cent, are, as a rule, not sufficiently thinly fluid to ex- pel fine particles of dirt. The 80 pounds of caustic soda lye of 35° B. are mixed with 10 pounds of water and 30 pounds of the potash solution of 25° B. With the resulting lye the fats are saponified and the lye is kept at a temperature of 201° F. As soon as combination is established, the salt water is gradually added and later on the re- maining 70 pounds of potash solution of 25° B. The kettle is then well covered for about one hour, after which the soap is thoroughly crutched and tested. A sample should be hard, not lardaceous to the touch and pliant ; if otherwise, fitting is want- ing, which is effected in summer by adding a few pounds more of caustic soda lye and perhaps a few pounds of salt water, but in winter by salt water alone so as to avoid moulding of the soap. After the addition of lye or salt water the soap is again heated. When a sample shows the soap to be sufficiently solid, it is again covered and a moderate coal fire kept up under the kettle to disperse the froth. The slight coat of froth which finally re- mains is lifted off, and after the clear soap is brought into low sheet-iron frames, the surface is drawn curly with a rod, and the soap left standing uncovered. In about eight hours it is ready for cutting. The brilliantly white bars are dried in the air and provided with the factory stamp. The same combination of fats can also be converted into soap by HARD SOAPS. 363 indirect boiling and filled with water-glass or talc. Such a formula would be about as follows : 100 pounds of tallow are boiled to grain with 240 pounds of caustic soda lye of 13° B., while 200 pounds of palm-kernel or cocoanut-oil are boiled to a paste-soap with 135 pounds of caustic soda lye of 35° B., 60 pounds of water-glass, 60 pounds of water, and 5 pounds of common salt. The process is carried out by first boiling the grain, and after emptying the kettle introducing at once the 135 pounds of caustic soda lye of 35° B., the water, and the salt. After heating this mixture to 189.5° F., the water-glass is added, and the whole thoroughly crutched. The warm grain is then added, and the previously melted palm- kernel or cocoanut-oil crutched in. Com- bination takes place by keeping the soap at from 189° to 200° F., a quite thinly fluid soap free from froth being formed. The soap is not covered, but slowly crutched until a sample shows it to be sufficiently solid. If too soft, it is hardened by adding a few pounds of caustic soda lye. It might, however, be possible that evaporation has been carried too far and the resulting soap be brittle and rough. In such a case add hot water holding a little salt in solution. Paste-soaps with a yield of 300 to 350 per cent. — The manu- facture of these soaps offers less difficulty than that of the pre- ceding as long as only smooth or simply colored soap is to be prepared. However, the marbled variety known as English mottled soap or Eschweg III. also belongs to this class. The simplest way of preparing these sdaps is by using a form- ula consisting of palm-kernel or cocoanut-oil 100 pounds, caustic soda lye of 36° B. 60 pounds, potash solution of 25° B. 100 pounds, salt water 60 pounds. The process is easy and sure, though it is necessary, as is the case with every other kind of soap, to adhere to the principle of not adding the salt solutions until the fats and lye are thoroughly combined. The formula may also be so changed as to use tallow or fats in connection with palm-kernel or cocoanut-oil. As much as one-half the quantity of tallow or palm-oil may be used ; of soft fats it is, however, advisable not to exceed 30 parts to 70 parts of cocoanut-oil, and of still softer or liquid fats 20 parts to 80 parts of cocoanut-oil. The other proportions remain the 364 MANUFACTURE OF SOAP AND CANDLES. same, though the strength of the caustic lyes is best reduced 1° to li°. With these soaps much talc is used as a filling material. The fats are heated to 189.5° F., the talc crutched in, and the lye added. The following is a suitable formula : Cocoanut-oil 100 pounds, talc 50 pounds, caustic lye of 36° B. 60 pounds, potash solution of 25° B. 80 pounds, salt water of 20° B. 50 pounds. The following formula, which is almost the same as the above only that water-glass is added, might be preferable as the soap keeps better :— 100 pounds of cocoanut-oil, 50 60 40 10 3 10 50 pou TalC, caustic soda lye of 36° B., water-glass, mixed with caustic soda lye of 36° B., common salt, dissolved in water, rids of tank-lye of 3° B. The operation is carried on as follows : The talc is stirred into the fats heated to 189.5° F. While keeping the mass at this temperature, the 60 pounds of caustic soda lye of 36° B., pre- viously mixed with the 50 pounds of tank-lye of 3° B., are crutched in. When a thorough combination is formed, the salt water is added and then the water-glass solution. Samples are now taken, and if they are hard the kettle is covered to allow the froth partially to disperse and partially collect on the top. The portion of the froth collecting on the top is then lifted off' and the whole crutched for some time to prevent the talc from settling. The soap is finally brought, at a temperature of about ] 56° F., into low frames. To promote cooling any cuttings of the same soap which may be on hand are added to the hot soap in the frames. By substituting in the above formula palm- kernel oil for cocoa- nut-oil, the soap may be prepared by first boiling the fat to grain. The filling, which consists also of talc and water-glass, is finally crutched into the grain-soap. This gives a milder product, no lye being added to the water-glass. Such a formula consists of: — HABD SOAPS. 365 100 pounds of palm-kernel oil, boiled with 100 " caustic soda lye of 25° B., 50 " talc, 30 " water-glass, mixed with 20 " water, 30 " salt water of 50 K. Ninety to 95 pounds of the caustic socla lye of 25° B. are gradually crutched into the palm-kernel oil heated to 189.5° F. The reason for reserving 5 to 10 pounds of the lye is because as the action of the lye varies very much, the quantity given in the formula may be too large. When a thorough combination is es- tablished, 4 pounds of common salt dissolved in 8 pounds of water are added and the mass is kept at a boiling heat, though actual boiling is not necessary. The object is attained if the soap separates in the manner of grain-soap upon a precipitate of paste ; otherwise caustic lye of 25° B. is crutched in until sepa- ration takes place. The settled grain-soap is ladled into a barrel, and after removing the sub-lye returned to the kettle. The liquor resulting from stirring the 50 pounds of talc into the 30 pounds of hot salt water of 5° B. is then heated to from 144.5° to 167° F. and crutched into the grain. When the whole forms a thoroughly combined soap, the 30 pounds of water-glass mixed with the 20 pounds of water and heated to 144.5° F. are gradu- ally added. English mottled soap. — This soap, also called Esehweg soap III., is also a filled soap, which is, however, marbled by the formation of flux. This variety of soap is best formed in frames holding 1200 to 1600 pounds. The following is a suitable formula : — 400 pounds of palm-kernel oil, 200 it cocoanut-oil, 300 a caustic soda lye of 36° B., diluted with 200 a water, 72 it common salt, dissolved in 144 a water, 120 u potash and 30 a calcined soda, dissolved in 600 a water, 2 it ultramarine, stirred into 16 it water, and 30 a water-glass added thereto. 366 MANUFACTURE OF SOAP AND CANDLES. The 400 pounds of palm-kernel oil and 200 pounds of cocoa- nut-oil are melted and saponified with the 300 pounds of caustic soda lye of 36° B., previously diluted with the 200 pounds of water, the mass being kept at a temperature of 189.5° F. As soon as combination is effected, some of the salt water is added and later on the solutions of soda and potash. The kettle is then covered and the soap, which should show a temperature of about 189.5° F., is allowed to stand for one hour, when the base-soap will be quite free from froth. It is then thoroughly crutched and tested as to whether it will draw threads. If it drops from the spatula it is too weak, which is remedied by adding a few pounds of caustic lye of 30° B., again heating and crutching. When the base-soap is uniformly warm and bright, about 20 to 30 pounds of it are taken from the kettle. The ultramarine and water-glass are mixed together cold by first dissolving the color in the water and then adding the water- glass. In order to test whether the base-soap is adapted for coloring and marbling, some of the coloring mixture is mixed with the 20 to 30 pounds of soap taken from the kettle. If the sample ac- quires a uniform blue color the base-soap is so alkaline as to render it impossible for the water-glass to crystallize out. By now adding to this colored sample 200 to 400 pounds of melted palm-kernel oil and stirring it uniformly through the soap, the oil withdraws from the latter so much sharpness that the coloring substance separates in large flakes, which form the marbling. If the soap has a suitable temperature, about 158° F., it is so thickly fluid that the marbling formed cannot subside, but remains uni- formly distributed throughout the soap. As soon as this is estab- lished with the sample of 20 to 30 pounds, the soap in the kettle is allowed to stand covered for some time. If after-heating takes place the flux, as a rule, subsides and has to be again crutched up, it being reformed as long as the soap is hot enough. For soaps inclined to after-heating it is best to let them stand in the open frames, which should not be made too full. If the coloring substance added to the sample of soap does not distribute itself in it, but crystallizes out, the base-soap is not sufficiently alkaline. To remedy this, either lye is added to the soap or, if but little is HARD SOAPS. 367 wanting, a few pounds of caustic lye are added to the coloring substance and a fresh test is made. All samples no longer suit- able for testing are returned to the kettle and fresh ones taken. In mixing the coloring substance with the sample it may happen that broad streaks are formed, which, after a short rest, contract to a large, broad marbling. This, as a rule, is the most successful soap and need not be covered. This test with a small sample is absolutely necessary before bring- ing the soap into the frames. When it is found that the soap is suitable for coloring, it is brought into the frames at a tempera- ture of from 167° to 174° F., and, after covering the frame for a short time to allow the froth to disperse, the coloring substance is crutched into the frame, and, if necessary, the melted palm-kernel oil. All observations and changes made in manipulating the small samples are followed up on the soap in the frame. Any spoiled soap is re-melted together with any cuttings on hand, and again brought in the frames. Much patience and considerable experience are required for the successful manipulation of this kind of soap. Resin-paste soaps. — The favorite of these soaps is the pale- yellow variety with a yield of 330 to 350 per cent. A suitable formula consists of : — ■ 180 pounds of cocoanut-oil, 20 " crude palm-oil, 40 " resin, 140 " caustic soda lye of 36° B., 180 " water, 80 " water-glass, mixed with 20 " caustic soda lye of 36° B., diluted with 4 " common salt, dissolved in 16 " water. The resin is dissolved in the melted cocoanut and palm-oil. The caustic lye diluted with the water is then added, and the whole kept at a boiling heat, even actual boiling doing no harm. The salt water is then added, and the mass kept at the same tempera- ture for one to two hours. The water-glass mixed with the caustic lye is finally added, and the kettle allowed to stand covered for at least one hour. The mass is then thoroughly crutched and a sample taken. Should the soap prove too soft, it is hardened with caustic soda-lye. 368 MANUFACTURE OF SOAP AND CANDLES. These soaps must, however, contain neither too much lye nor too much salt, as otherwise they turn out moist and mottled. If, therefore, the sample is any way solid, it is best not to add any more caustic lye, but to dry the cut soap. If a higher color is de- sired, 30 to 40 pounds of crude palm-oil may, without injury, be used instead of 10 pounds. The following formula is nearly the same, talc being substituted for water-glass as filling material :■ — 160 pounds of cocoanut-oil, 40 < i crude palm-oil, 40 a dark resin, 140 u caustic soda lye of 36° B., diluted witli 1(50 < i water, 100 a talc, 6 n common salt, dissolved in 34 it water. The 100 pounds of talc are stirred into the melted fat and resin, and the whole saponified with the caustic lye, after which the salt water is added. The only difference in the manipulation of this soap from the preceding one is, that it should not be allowed to boil, but kept at a temperature of about 189.5° F. When a sample shows the soap to be sufficiently solid, it is ladled into the frames and crutched to prevent the talc from settling. For a finer quality of soap filled only with solutions of potash and common salt, the following formula may be used : — - 140 pounds of cocoanut-oil, 40 " tallow, 20 " crude palm-oil, 40 " pale resin, 140 " caustic soda lye of 36° B., diluted with 60 " water, 160 " potash solution of 30° B., 80 " common salt solution of 22° B. This soap does not require boiling, being only kept at a tem- perature of 189.5° F. After dissolving the resin in the melted fat, the liquid mass is passed through a hair-sieve, returned to the kettle, and saponified with the caustic lye. When combination is established, the solutions of common salt and potash are gradually added. A sample taken from the kettle should show a consider- HAKD SOAPS. 369 able degree of solidity, otherwise the resulting soap will be too soft. If necessary, a few pounds of crystallized soda, and, per- haps, a little caustic lye, are added, the soap being again heated after each addition. After frequent crutching, the soap, at a tem- perature of from 144.5° to 156 F.°, is brought into low frames. The color of brown resin-paste soaps is due to the dark resin and the fats used. The following may serve as a formula : — 150 pounds of cocoanut-oil, 50 " wool fat, 40 " dark resin, 140 " caustic soda lye of 36° B., diluted with 140 " water, 80 " water-glass, mixed with 20 " caustic soda lye of 36° B., 6 " common salt, dissolved in 14 " water. The process of manipulation is the same as for the preceding soap. In case the soap should not turn out dark enough, it is colored with 4 pounds of sugar color dissolved in potash solution. The yield of these soaps may be increased to 400 per cent, and more by the addition of carbonated lye, crystallized soda, or salt solution, 4 pounds more of caustic lye of 36° B. being calculated for every 20 pounds. Such soaps are, however, inclined to efflo- rescence, and are rendered hard and rough by the addition of a larger percentage of water-glass. Paste-soaps with a yield of 500 to 600 per cent- — The following soaps with a yield of 500 to 600 per cent, are prepared either smooth or marbled. The smooth soaps are allowed to retain their natural color as derived from the fats used in their preparation, or are artificially colored, while the marbled soaps are partially artificially mottled and partially so boiled as to become mottled by the formation of flux. The following is a formula for smooth soaps : — 1G0 pounds of palm-kernel oil, 40 " cocoanut-oil, 120 " caustic soda lye of 36° B., diluted with 120 " water, 50 " potash and 50 " calcined soda, dissolved in 24 370 MANUFACTURE OF SOAP AND CANDLES. 200 pounds of water, 120 " salt, dissolved in 200 " water, 40 " caustic soda lye of 36° B. for fitting. Combine the 200 pounds of oil with the 120 pounds of caustic lye of 36° B., previously diluted with the 120 pounds of water at 189.5° F. By adding the solution of common salt too soon, combination is rendered difficult and sometimes almost impossi- ble, and all subsequent defects of the soap can be traced to faulty saponification. After adding the solutions of common salt and of potash and soda, keep the soap at a boiling heat, and only if a sample of it should not prove solid enough add gradually a sufficient quantity of the 40 pounds of caustic lye of 36° B. pre- scribed for fitting. It may be necessary, in order to obtain the soap of sufficient hardness, to use even more than the 40 pounds of caustic lye of 36° B. prescribed, which may be due to the lye not being caustic enough, as the caustic soda frequently contains much carbonate. In this case note how much lye is used for saponification and subsequent hardening and take 10 to 12 pounds less of calcined soda for a subsequent boiling. The soap is brought into the frames at a temperature of 167° F., covered for one hour, and then let stand uncovered. These soaps may be colored red with bole, colcothar, or cinna- bar. To color them yellow, substitute about 20 pounds of crude palm-oil for 20 pounds of palm-kernel oil and add about 10 J ounces of potassium bichromate, dissolved in hot water, to the soap. A brown color is obtained with sugar color. A similar formula with talc filling is as follows :- — 40 pounds of cocoanut-oil, 160 i (, palm-kernel oil, 100 i t tftlC. 120 a caustic soda lye of 36° B., diluted with 120 4 i water, 80 it potasli and 40 it, crystallized soda, dissolved in 200 a water, 100 i i common salt, dissolved in 160 a water, 40 i i caustic soda lye for fitting. HARD SOAPS. 371 The soaps filled with talc are prepared in the same manner as the preceding ; they are, however, brought into the frame at a temperature of 167° F. and crutehed until they are cold and thick to prevent the talc from settling. It is advisable to remove any froth formed in the frame, as it is apt to form stains in the clear soap. These soaps are also colored. A third formula with water-glass is as follows : — 160 pom ids of palm-kernel oil, 40 ' ' cocoanut-oil, 120 ' caustic soda lye of 36° B. , diluted witli 120 < 1 water, 100 ' 1 water-glass, mixed with 20 1 caustic soda lye of 36° B. 40 4 crystallized soda, and 20 ' potash, dissolved in 200 ' water, 20 ' common salt, dissolved in 60 ' * water, 60 < ' caustic soda lye of 36° B. for fitting. The process is the same as for the preceding soaps. Combine the fats with the caustic soda lye, add the solutions of common salt and of potash and crystallized soda, and after boiling the whole thoroughly, add the water-glass and take samples. If the soap is not solid enough, add as much caustic soda lye as is required. The last variety of these soaps is that filled with talc and water-glass, which, on account of the filling material employed, dries out least of all. The following formula may be used : — 160 pounds of palm-kernel oil, 40 ' cocoanut-oil, 120 « ' talc, 140 ' ' caustic soda lye of 36° B., diluted with 140 < ' water, 120 ' water-glass, mixed with 40 ' 4 caustic soda lye of 36° B., 40 ' ' crystallized soda and 20 ' potash, dissolved in 160 ' ' water, 20 ' ' common salt, dissolved in 100 < ' water, 40 * ' caustic lye of 36° B. for fitting. 372 MANUFACTURE OF SOAP AND CANDLES. The talc is stirred into the melted fats and the latter are sapon- ified with the caustic lye at 189.5° F. When a thorough com- bination is established the salt water and solutions of soda and potash are alternately added and finally the solution of water- glass. The soap is kept at 189.5° F. and fitted with caustic soda lye. If correctly fitted, this soap is more thickly fluid than the preceding ones and hence can be brought hotter into the frames, where it is, however, somewhat crutched. This variety of soap is also adapted for artificial marbling, which is best effected by taking a portion of the soap from the kettle, heating it right hot, and coloring it with coloring matter stirred in water or oil. The soap remaining in the kettle is then cooled to about 133° F. by crutching. A layer about If to 2 J inches thick is then brought into a low frame ; upon this are poured thin rows of the colored soap, which are drawn and crutched in so as to form colored streaks. This is alternately continued until the frame is filled, when the soap is allowed to stand uncovered. The more skilfully this manipulation is exe- cuted the better the appearance of the soap. Soaps with a yield of 500 to 600 per cent, can also be marbled by the formation of flux. The following may serve as a formula : — 200 pounds of palm-kernel oil, 140 it caustic soda lye of 36° B., diluted with 200 i i water, 60 a potash and 60 a calcined soda, dissolved in 200 a water, 140 ( i common salt, dissolved in 140 a water. The base-soap is prepared like the "preceding, and, as a rule, requires no lye for fitting ; but if the soap is too soft, caustic soda lye of 36° B. is added. The soap is brought into the frame at a temperature of 167° F. and the coloring substance, stirred in water, crutched in. For the above formula about 10 ounces of ultramarine and 3 J ounces of Frankfort black suffice for a blue-gray color. The coloring material is mixed with about 10 pounds of hot water and 10 pounds of water-glass, about 10 pounds of tank-lye of 20° B. HARD SOAPS. 373 being finally added to the mixture. After the coloring substance is uniformly distributed throughout the soap and the latter cooled off to about 149° F., about 10 pounds of melted palm-kernel oil are added and the whole thoroughly crutched. In about half an hour, during which time the frame remains covered, a large, broad flux will have formed. Should the soap have again be- come heated, which is determined with the thermometer, the flux, as a rule, subsides. The whole must then again be crutched up, and this operation, if necessary, repeated. Liverpool-soap. — Under this name a yellow soap is manufac- tured with a yield varying between 300 and 800 per cent. This soap was originally prepared from crude palm-oil, the dirty sedi- mentary oils being used. Paste-soaps with a yield of about 360 per cent, possess the peculiarity of purifying themselves by ex- pelling all particles of dirt, the heavier and coloring substances falling to the bottom, and the lighter ones forming a coat of froth on the top. Crude palm-oil was formerly brought into commerce in an en- tirely impure state and had to be melted and clarified, but at the present time almost all oil is purified before it reaches the market. The sedimentary oils form, however, still an article of commerce, especially in England, and generally serve for the fabrication of the yellow Liverpool-soap. Crude palm-oil enters into a thorough combination with caustic lye, and the resulting soap is quite solid with a yield of 400 per cent. The manufacture is effected by two different methods. The sedimentary oil is boiled either upon strong salt-lye, so that the grosser dirt subsides, or it is directly boiled to a soap which is made to yield 400 per cent, by the addition of carbonates. As grain-soap boiled from the oil contains considerable dirt, it is dis- solved in carbonated lye of about 10° B. and hardened with salt. About ten per cent, of resin is also frequently used in connection with the oil, the resulting soaps yielding a more abundant lather. Transparent resin paste-soap. — This name is given to soaps which appear transparent on the edges of the bars. This is effected by the fats used and an addition of alkalies. A favorite 374 MANUFACTURE OF SOAP AND CANDLES. formula is as follows: Ceylon coeoanut-oil 180 pounds, crude palm-oil (Lagos) 20 pounds, pale resin 40 pounds. The fats are saponified with caustic soda lye of 22° B., to which about 25 per cent, of potash solution of 28° B. is added. The transparency depending on the addition of potash lye, only lyes and fats as pure as possible should be used, and the soap hardened only when it boils perfectly clear. For hardening salt water of 24° B. is used, though potash water-glass can be substi- tuted for a portion of the salt. The generally very thick water- glass is diluted with potash lye of 2° B. until the solution shows 20° B., and is then alternately added with the salt water. A sufficient degree of hardness and permanent transparency is as- certained by repeated examination of samples. The soap when correctly prepared retains its transparency and is elastic on the cut surface, but later on becomes harder. By the use of crystal- lized soda for hardening the transparency suffers somewhat, though it may suffice in some cases. It is recommended to guard against the use of too much common salt. Transparent resin paste-soap (another method). — First prepare a lye, not too caustic, of 30° B. Then combine in the kettle by slow boiling 70 pounds of cocoanut-oil, 30 pounds of crude palm-oil, 20 to 25 pounds of resin with about 30 pounds of the lye of 30° B., and then stir in with a more moderate fire, so that the mass does not boil, 50 pounds of the lye of 30° B. The soap should show a strong touch. Heating is then discontinued, and 20 pounds of carbonate of potash solution are sprinkled over the soap and crutched in, the result being a strong paste. Now add with constant stirring 70 pounds of water-glass, previously diluted with 3 pounds of alcohol and 3 pounds of lye of moderate strength, and cover the kettle for half an hour. Then ladle the soap into the frame, covering it well so that it will thoroughly crystallize. HARD SOAPS. 375 CHAPTER XIV. HARD SOAPS (CONTINUED). III. Half-Grain Soaps. The fact that the manufacture of these soaps (called in Ger- many Eschweg soap) has been introduced wherever soap-factories exist, is a proof that the product is better than its reputation. The cheap price at which the soaps can be sold is not so much due to the product itself as to the easy manner of boiling and the consequent fabrication of enormous quantities. Half-grain soaps can only be prepared with the assistance of cocoanut-oil or palm-kernel oil. They are boiled by either one of three methods : (1) indirectly, by a preparatory boiling to grain of a portion of the fats, (2) directly, by boiling all the fats together, and (3) from base-soaps, by first boiling the fats to a grain-soap, which is then augmented, as far as its consistency will permit, with carbonated lye, common salt, and water-glass. Half-grain soaps by the indirect method. — The manufacture of these soaps consists chiefly in a preparatory boiling to grain of a portion of the fats, the object being the removal of coloring mat- ter frequently adhering to poorer qualities of fat. Boiling by the indirect way being the easiest method of obtaining a beau- tiful product it is advisable for soap-boilers wishing to introduce these soaps to become proficient in it before attempting the manufacture by direct boiling from palm-kernel oil in connection with lighter fats, such as linseed-oil and cotton-seed oil, and aug- menting the soap with water-glass and talc. The quality of half-grain soap is intimately connected with its appearance, it being by no means insured by the use of the best fats, such as tallow, palm-oil, and cocoanut-oil. Such soap may show defective formation of flux and faulty consistency, become 376 MANUFACTURE OF SOAP AND CANDLES. tray-shaped in drying, lose much in weight, and wash away rap- idly. It may be wanting in firm combination, a defect frequently due to over-evaporation. Strongly evaporated half-grain soap must not be fitted too sharp nor forced too far with salts. The appearance of the soap will be best when one is enabled by a suit- able combination of fats to prepare a firm lardaceous product which is frequently not attained even by the use of solid fats alone. The best formula for the purpose is to use for 100 pounds of lardaceous fat, by which is understood a composition of half tallow or palm- kernel oil and half bone-fat, lard, etc., 50 pounds of cocoanut-oil as a combining fat. If softer fats, such as horse-fat, cotton-seed oil, sesame-oil, peanut oil, etc., are to be worked, it is advisable to take only one-third of these fats to two-thirds of solid fats (tallow or palm-oil). Half-grain soaps are never boiled without the addition of a fat securing;; a solid combination, cocoanut-oil or palm-kernel oil serving for the pur- pose. The following formula may serve to illustrate the execution of the operation : Bone-fat or lard 1000 pounds, tallow or palm- oil 1000 pounds, cocoanut-oil 1000 pounds. The 1000 pounds of bone-fat or lard and the 1000 pounds of tallow or palm-oil are slowly boiled with about 1000 pounds of caustic lye of 12° B. until a thorough union is estab- lished. In case this requires a long time, so that much water evaporates, which would make the lye stronger and the process of combination difficult, 20 to 40 pounds of water are added. However, if a union is not effected by these means, the furnace door is opened or the steam shut off and the mixture allowed to stand until the fat and lye are observed to combine. Firing is then slowly continued and 50 pounds more of lye are added, and when these have thoroughly combined the addition of lye is con- tinued until the paste becomes bright and thick and the soap, after a further addition of lye, commences to " wet." For the saponification of 200 pounds of fat about 400 pounds of caustic lye of 12° to 13° B. are, as a rule, required. The paste generally " wets" before all the lye has been added. To separate the paste about 8 per cent, of common salt of the fat used is brought into the kettle simultaneously with the rest HARD SOAPS. 377 of the lye. By assisting with the crutch the soap tears and rises up broken. After boiling for some time the soap is tested as to sharpness, and in case the sub-lye indicates such, it will also be always perceived in the soap, which boils thick, forces up the clear, round grain, and is of hard consistency. Such clear grain, which is generally formed by the evaporation of too much water, is not required for half-grain soap. If, now, water be poured over the soap, the grain is dissolved, the entire mass boils up high and with greater ease, and an augmentation of the grain takes place by the mass absorbing the greater portion of the sharpness previously observed. If the formation of such a grain is at once attained by direct boiling, the after-boiling and addi- tion of water are omitted. The grain is now allowed to separate from the sub-lye, and, if there is but one kettle, it is ladled into barrels. For the second operation — boiling to combination — about 1 00 pounds of tank-lye of 24° B. are brought into the kettle for every 100 pounds of cocoanut-oil. The lye used for the purpose is the first runnings obtained by treating calcined soda with lime. Any soap-cuttings on hand are dissolved upon the lye ; otherwise it is allowed to boil up by itself. The grain-soap in the barrels is then added and the whole boiled thoroughly through upon the combining lye until a thick, clear grain is formed. The cocoanut- oil, with the exception of 100 pounds, is then introduced, the mass being kept at a gentle ebullition and moderately crutched to promote the uniform distribution of the cocoanut-oil and rapid combination. After boiling for some time longer the soap is tested. If it shows any sharpness the retained 100 pounds of cocoanut-oil are added ; but if sharpness is wanting, some caustic lye of 24° B. is first introduced and boiled through with the mass, and then the cocoanut-oil. A low percentage of combining lye having been intentionally given, it may happen that too little sharpness is present if the grain is so far ground out as not to be able to retain an excess of sharpness. If, however, the above directions for boiling have been approximately followed, there is but one thing which may apparently be wanting in a regular half-grain soap, and that is water. To be sure, no direct, valid 378 MANUFACTURE OF SOAP AND CANDLES. information can be given in this respect, but the soap-boiler can confidently proceed with fitting, which is effected with salt water. The cuttings and the grain having been boiled clear upon the combining lye and the cocoanut-oil crutched in with moderate boiling, it is not likely that a frothy soap will be formed at this stage. There may, however, be a lack of water due to evapora- tion ; the soap may be thin, which indicates that water is wanting. To such soap add carefully salt water of 5° B., half cover the kettle and boil until the soap is bright ; and the thicker it boils afterwards the more salt water (of 10° to 15° B.) must be used and the boiling continued with the addition of salt water until the soap breaks into beautiful light roses. A sample when placed upon the warm board covering the kettle should remain warm for some time, and after cooling have a uniform white ap- pearance and break, not viscid, but like curd-soap. It may hap- pen that after adding 5 to 6 per cent, of salt (of the quantity of cocoanut-oil used) there may show itself some sharpness and con- sequently a slight froth, which is removed by the addition of a few pounds of cocoanut-oil mixed with water. It will frequently occur that these soaps lie thick and compact in the kettle. To such soap it is best to add salt water of 5° B. from the start and then proceed in the same manner as before. Further, the soap formed may be viscid and have a glassy ap- pearance, though be thick and free from froth. This indicates lack of sharpness and that the soap needs caustic lye. Add first strong salt water of 20° B., and if the soap does not change after the addition of about four per cent, of salt, add caustic lye of 20° B., but not too much, so that salt water may be subsequently used. Half-grain soaps prepared with the use of cocoanut-oil can bear much common salt, but the exact quantity cannot be given, as it depends on the content of alkalies in the soap. They also demand alkaline carbonates for augmentation in order to keep them free from froth. The addition of salt water serves for hardening, which otherwise would have to be effected by means of caustic lye. In summer even a large quantity of carbonates in the soap does not matter, but in winter it is advisable to de- crease the quantity of carbonates as much as possible and add HARD SOAPS. 379 salt instead in order to prevent efflorescence. The yield obtained is satisfactory and could not be increased by another method of boiling nor by such filling agents as talc and water-glass. The soap should not be boiled down too much and too firm, but when boiling easily and breaking into roses over the entire surface is brought into the frames and crutched until cooled to 167° F. The frames are then lightly covered. If in the course of three hours layers of flux lying closely alongside each other are ob- served to form, the frame is uncovered and the soap allowed to cool completely. By omitting the cocoanut-oil from the above formula and using palm-kernel oil alone, the behavior of the soap during boiling differs somewhat from the preceding, as palm-kernel oil does not form as strong a combination as cocoanut-oil and cannot stand as much alkali and salt for augmentation. The process of boiling is the same as the preceding up to the point of fitting and short- ening. To such soap salt water of 5° B. is added. If changes take place after this addition, so that the soap becomes thinner, the alkali takes effect, and though no sharpness may be percep- tible some palm-kernel oil, or, still better, some cocoanut-oil has to be added. This strengthens the combination and the soap re- covers at once. It will stand about four per cent, of salt, and this quantity and perhaps more have to be added in order to keep the soap free from efflorescence in winter. By using a smaller quantity of palm-kernel oil or cocoanut-oil than one-half the charge of fat, the boiling of half-grain soap is always uncertain. Soaps firm enough for cutting can be obtained by boiling with 40 per cent, of palm-kernel oil or 35 per cent, of cocoanut-oil, but hardening is effected at the expense of yield. Furthermore the soap has to be correspondingly evaporated. If this is not done tricolored soaps are formed, which though de- rived from the same kettle show in the frame the remarkable phenomenon of being firm and homogeneous above and below and in the centre, but dull and weak in some places and hard and piebald in others. This is due to the grain-soap not having been entirely dissolved and is corrected by again evaporating, whereby other defects will show themselves and can be remedied. Add also two to three per cent, of dissolved salt to the soap, and 380 MANUFACTURE OF SOAP AND CANDLES. should this effect the combination or fitting assist with palm- kernel or cocoanut-oil beaten up in water. Good soap shows but little sharpness and remains free from efflorescence. The yield of such soaps when freshly cut is satisfactory, the rate depending on the evaporation. Slightly evaporated soaps lose, however, 30 per cent, by after-drying, and hence claims are frequently made on this score, though the buyer may have been satisfied with the appearance of the soap when first received. Too strong drying out is prevented by additions of water-glass and talc, but a different manner of boiling upon the combining lye becomes necessary, since the latter has to be more caustic with the use of water-glass. Silicate of soda exerts a stronger effect than salt upon easily boiling soap containing water, and hence weak lyes should never be used, as the water-glass breaks the soap up, a defect which cannot be remedied. With the formula previously given, except that 10 to 15 per cent, of water-glass is to be used, the preparatory boiling to grain remains the same. A different lye is, however, used for the saponification of the cocoanut-oil or palm-kernel oil, for 100 pounds of oil, 50 pounds of tank-lye of 24° B., and 50 pounds of caustic soda lye of 28° B. being taken. The general custom is to add the water-glass at once to the lye, and after starting the fire to dissolve upon the boiling lye containing the water-glass the soap-cuttings and the grain. The lye becoming more con- centrated by boiling, it would, however, be more advisable to first dissolve the cuttings and the grain upon the lye and then to add the water-glass and allow the whole to boil through. In in- troducing the palm-kernel or cocoanut-oil into the kettle, ebulli- tion should be constantly kept up and the crutch diligently used. The addition of fat is interrupted as soon as a curly, woolly soap boiling uniformly all over the kettle is formed : 10 per cent, of the oil should be always retained for the reason previously men- tioned. Test the soap as to hardness and touch, and if both be satisfactory allow it to boil quietly until no more evaporation is observed, when the fitting is regulated and salt added. Of the latter but little is, as a rule, required, especially with the use of palm-kernel oil. For palm-kernel oil one per cent, dissolved in water to 20° B. and for cocoanut-oil three per cent, can be taken HARD SOAPS. 381 without injury. If the soap is sharp it at once boils thinner, but recovers by adding palm-kernel oil or cocoanut-oil. These soaps must be kept in constant ebullition until finished, it being difficult to raise them up again after they have once fallen down in the kettle. The soaps may be considered finished when they uniformly break into roses up to the brim of the kettle. Fitting to touch should be very mild and scarcely perceptible. Except there be too much sharpness none of the water-glass is separated out. This defect is recognized by a sample not remaining piled up in a heap, but spreading out flat. No one can assert that water-glass augments such soap, it being contrary to the entire manner of boiling, and, moreover, it gives a smaller yield than the preceding one, but dries out only about 20 per cent. The soap is framed hot, thoroughly and uniformly crutch ed, and tightly covered. With the use of talc as a filling agent the process of boiling is the same as for the preceding soap. In working lyes of such strength as 24° and 28° B., the soap may be expected to be lacking in water and consequently boil gray and thin. But this need not trouble the soap-boiler much as long as he is sure of the correct- ness of the process in other respects, because the hot filling which is kept ready in a vessel standing alongside the kettle will intro- duce into the soap all the water and shortening wanted. The more such soap is boiled down the better it can be handled. Soap containing much water cannot be filled during the boiling, as the talc being too heavy falls to the bottom where it creates mischief. The filling is prepared by mixing with constant stirring 100 pounds of talc with 125 pounds of hot water, and adding shortly before use two per cent, of salt. While one workman pours the filling over the soap by the ladleful, another one stirs constantly to prevent the talc from falling to the bottom. By the addition of the filling the soap should improve in appearance and boil thinner. If it is acted upon by the salt, it will look brighter but remain thin. If this be the case, add carefully palm-kernel oil or cocoanut-oil until the soap becomes thicker, and interrupt the introduction of the filling as soon as it is not immediately 382 MANUFACTURE OF SOAP AND CANDLES. absorbed by the soap, which is recognized by it falling to the bottom and scorching. The soap is finished as soon as it is satu- rated, it being possible to add 20 per cent, of talc in this manner. These soaps are also framed hot, crutched through, and tightly covered. Another kind of half-grain soap, prepared according to the above formula, is augmented by crutching in the filling. The base-soap is boiled in the same manner as the preceding, the boil- ing to grain especially remaining the same. For combining lye half-tank lye of 24° B. and half-caustic lye of 28° B. are used. However, the filling incorporates itself with ease and regularity only in soap of little yield. A filling agent much in use, but which, in our opinion, can scarcely be recommended, consists of two parts of crystallized soda and three parts of water-glass. The finished base-soap re- mains standing for two hours, when the crystallized soda is thrown into the hot soap and crutched through. When it is ob- served that all the crystals are dissolved, which requires but a short time, crutching is continued, and the water-glass sprinkled over the soap by means of a watering-pot and combined with it. In this manner soaps of a fair quality are sometimes obtained, but frequently they turn out faulty, the upper and lower layer being defective, and, moreover, they are inclined to efflorescence in winter. Many soap-boilers, after adding the crystallized soda and water-glass, crutch in talc and rice-flour. Stir together in as little water as possible (about 80 parts of water to 100 of flour) 1 part of talc and 2 of rice-flour and add to the mixture 20 per cent, of water-glass. This flour and talc filling is only added after the base-soap has been made " sick/' as it is called, by the crystallized soda and water-glass. With correct proportions the soap is considerably augmented, the flour forming the paste which holds the mass together. The soaps have a peculiar feel when freshly cut, but improve considerably by storing. Cuttings con- taining flour being difficult to utilize this process is not well adapted for large factories. Another process, which is still much in use, of preparing half- grain soap according to the above formula is as follows : The soap-cuttings are allowed to dissolve upon tank-lye of about 22° HARD SOAPS. 383 to 23° B. The cocoanut-oil or palm-kernel oil is then added and boiled to a paste-soap free from froth. The grain is next added and thoroughly boiled through. The soap is finally filled with one of the filling agents previously described. As a rule such soaps are too sharply fitted, especially when the grain has been boiled with strong lye. This is remedied by the addition of palm-kernel or cocoanut-oil. The oldest and simplest method is, no doubt, to boil the larda- ceous fats to grain with tank-lye of 12° to 13° B. The mass is boiled while in paste for a considerable time, thus insuring the saponification of all the fat, and when a cooled sample shows con- sistency and begins to wet when pressed between the fingers, it is salted out with 5 to 7 per cent, of common salt. The exact quan- tity of salt required for separation cannot be given, as it depends on the various fats. Separation with salt being effected, boiling is continued for at least one hour, and, if necessary, sufficient water added to liquefy the grain. After this the grain frequently draws together with the lye, the entire soap becoming pasty. Hence close attention has to be paid to the boiling of the grain, and samples taken with the spatula and tested whether the sub- lye is clear ; otherwise boiling has to be continued until this is the case. Salt dissolved in Avater is then added. In case the fats are strongly colored and yield the coloring matter to the sub-lye, the latter may be drawn off or pumped out, but it is seldom necessary, as half-grain soaps are of a sufficiently light color even when the grain is boiled only upon one water. The second water is only boiled upon salt water, i. e., sufficient salt is added to prevent the liquefied soap from becoming pasty. The grain-soap is covered warm and allowed to settle. In the meanwhile a paste-soap is prepared from cocoanut or palm-kernel oil. For 100 pounds of oil, 100 pounds of tank-lye of 22° to 23° B. are brought into the kettle, and after allowing the soap-cuttings to dissolve upon it, 3 per cent, of common salt is added. Moderate ebullition is now kept up and the cocoanut- oil gradually introduced and crutched in. The whole is then allowed to boil up until any froth formed has disappeared. The use of more lye is not advisable, the quantity given sufficing in most cases. If, however, the lye is not sufficiently caustic, the 384 MANUFACTURE OF SOAP AND CANDLES. paste may become thick and pappy. In this case lye of 22° B. is added until a thin, bright paste is formed. If the first lye suffices, 250 pounds of potash solution of 10° B. are poured over the mass, and after allowing the whole to boil through, the fur- nace door is opened and the previously prepared grain crutched into the hot paste-soap. The addition of grain may be inter- rupted as soon as a thick soap is formed. The less grain is crutched in the higher the yield. It is possible that such soap may turn out well without regu- lating the fitting, but it is best to be guided by samples taken as soon as the soap begins to develop net-like. If the sample be glassy but firm, salt is wanting ; if glassy and soft, fitting lye. Soap remaining thin is too sharp, and thick soap remaining soft, but showing sharpness, lacks water. If obliged to add anything to soap thus crutched together, it is advisable to do it as warm as possible, and even with the furnace door open keep up sufficient fire for the bottom of the kettle to remain hot. In the worst case allow the soap to boil up, and in order to effect this with greater ease, gradually add water and fit the soap quite mildly. If water-glass is to be used for such soaps the process of boil- ing remains the same, but caustic lye of 24° B. (100 pounds of lye for 100 pounds of oil) is taken for preparing the cocoanut-oil paste-soap, and after allowing the soap-cuttings to dissolve upon it, the water-glass is added. The cocoanut-oil having combined, care must be had to see that there is sufficient sharpness, other- wise the water-glass will separate out. The use of carbonated lye cannot be recommended, but about 100 pounds of salt water of 12° to 15° B. may be added to the finished paste-soap. The crutching in of the grain into such paste-soaps must be carefully executed, though actually only two defects can occur. If the soap, after adding grain, becomes glassy or viscid, lye is wanting and should be added as quickly as possible. If the soap remains thin and will not develop net-like, it is too sharp, and melted palm-kernel oil or cocoanut-oil has to be crutched in. It is always best first to make a test on a small scale. Fifty pounds of paste-soap must absorb with ease and avidity 50 pounds of grain-soap, forming a net-like mass remaining warm for some HARD SOAPS. 385 time. The cooled sample should be white and hard and not viscid, but break off short like curd-soap. In adding the grain to the boiling paste-soap the same direc- tions have to be observed, fitting being regulated as much as possible before the addition of all the grain. In the preceding it has been endeavored to describe the various methods of boiling with one and the same formula. We would remark that it is, without doubt, the best formula for half-grain soap, since, on account of the high percentage of tallow-like fats used, the resulting product may be classed among curd-soaps pre- pared according to the old German fashion. There are, of course, other fats, especially those of a softer consistency, which can be used, but care must be had not to take too much of them. An examination of the grain is always the best guide of how far the soap-boiler can go with such additions. There is a series of soft fats, such as cotton-seed oil, peanut-oil, sesame-oil, and also horse- fat, from which curd-soap of a tolerably firm cut, with a yield of from 146 to 150 per cent., can be boiled, but as soon as it is ground it becomes soft. Formerly the following formula was much liked and may be recommended when good fats, tallow, and palm-kernel oil are cheap. The fats are proportioned according to their consistency, and may be replaced by others of the same consistency, for in- stance, bone- fat by glue-fat, cotton-seed oil by peanut-oil or horse-fat, tallow by palm-oil, etc. Bone-fat 500 pounds, tallow 400, cotton-seed oil 100, palm- kernel oil 700. The tallow and bone-fat are boiled to grain, but the cotton- seed oil only in case it is impure or strongly colored. The fear that with the use of a high percentage of bone-fat or glue-fat an irregular separation of lye may take place in boiling to grain is justified. This evil may, however, be obviated by bringing first the boiling lye into the kettle and adding four to five per cent, of common salt. After heating to effect a quicker solution of the salt, the bone-fat is introduced, boiled through, and then the tallow. Should it, however, happen that the lye does not separate after adding the salt, introduce 100 pounds of palm-kernel oil and add 10 to 12 pounds of salt. 25 386 MANUFACTURE OF SOAP AND CANDLES. Fats boil well upon lyes from lyes of curd-soaps upon a pre- cipitate of paste, their use serving a double purpose : the sharp- ness is utilized and the lye rendered clear. For the preparatory boiling to grain use tank-lye of 13° to 14° B., which is almost entirely caustic, or only pure caustic soda lye of 12° to 13° B., and boil with the addition of water until a bright, thoroughly ground-out grain is formed and the lye runs off clear. As the quality of bone-fat and glue-fat varies very much, they fre- quently containing dirt and water, the exact quantity of lye re- quired for saponification cannot be given. The soap-boiler may, however, proceed in the reverse order and bring, for instance, for the 900 pounds of fat, 1800 pounds of lye of 12° to 13° B. into the kettle, and when he finds non-utilized sharpness to be present add fat which will readily incorporate itself. The content of dirt and water can then at the same time be approximately calculated. Though the formula calls only for 20 per cent, more of com- bining fat than the preceding one, a different combining lye is nevertheless required in order to effect the saponification of the palm-kernel oil, which belongs to the fats which can only be sa- ponified with pure caustic lyes. Take 500 pounds of tank-lye of 24° B. and 200 pounds of pure caustic lye of 25° B., dissolve upon it the soap-cuttings, add the grain, and boil until a clear grain free from froth lies in the kettle. To many a one this may seem a singular requirement, but there are good reasons for it. Under different conditions grain-soaps boiled from fats give varying results, one of the injurious ones being that frequently a defective separation of the sub-lye in a hot state takes place. By adding such wet grain to the combining lye in the kettle, much saline lye is introduced, the result being a saline augmenta- tion which subsequently is frequently fatal to success. However, by evaporation the lyes, though saline, are sufficiently concen- trated to enter into correct saponification with the palm-kernel oil. The content of salt does no harm, it even belongs to every half-grain soap, but care must be had not to add subsequently carbonated lye or salt. It is still better and more rational to have always a supply of cold grain on hand, as it not only facili- tates the entire work, but makes it possible to boil at any moment half-grain soap in one kettle, whereas, if the grain is boiled on the HARD SOAPS. 387 same day, two kettles are required or the grain has to be ladled out. Discharging or pumping out the sub-lye does not suffice, because all such fats as bone-fat or glue-fat deposit a strong slime, which adheres so tightly to the bottom of the kettle that it can only be removed by scraping. Keeping grain on hand is so convenient that it will not be given up when once introduced. The process of preparation is as follows : All sub-lyes, or lyes derived from soaps upon a pre- cipitate of paste and containing no resin, are left in the kettle, and 1000 to 2000 pounds of fat, according to what may be re- quired, added. As soon as the mass boils, caustic soda lye of 14° to 15° B. is introduced until it is noticed by the grain-soap show- ing pressure that all the fat is saponified. As a rule these grain- soaps do not boil to paste, the lyes from soaps upon a precipitate of paste containing sufficient salt to prevent it. But even with- out such lyes the conversion of the fats into such soap is of ad- vantage, since it prevents loss by leakage of barrels, etc. The finished grain is best brought into small, low sheet-iron boxes, about 5 feet long, 2J feet wide, and 5f inches high, in which it becomes cold overnight. It is then cut into slabs, which are stored away, each kind of grain by itself, so as not to create confusion when yields are to be calculated. The cold grain is brought together with the soap-cuttings upon the combining lye, and as it dissolves as quickly as the latter there is no loss of time. Another advantage is that each day a boiling of half-grain soap can be finished in one and the same kettle, which cannot be well attained in any other manner. By using such cold grain one is sure of the lye adhering to warm soap having settled. About two per cent, of salt, if not already added to the combining lye, is then introduced, next the cotton-seed oil, together with 100 pounds of lye of 24° B. re- quired for its saponification, and the whole boiled thoroughly. In this manner the cotton-seed oil is best decolorized and ren- dered inodorous, and also loses its property of later on producing spotted soaps. Finally the palm-kernel oil is introduced, and allowed to combine with moderate ebullition and assistance with the crutch. When the soap boils high and uniform, it is tested as to fit. 388 MANUFACTURE OF SOAP AND CANDLES. All superfluous, premature doctoring, especially with so-called shortening agents, should be let alone. If the test shows the soap too sharp, add carefully palm-kernel oil previously stirred in water (100 pounds of oil in 100 pounds of hot water); if it is viscid and dull, sprinkle caustic soda lye of 25° B. in small por- tions over it. It may further happen that, though the soap boils high and bright, a cooled sample is not white but colored. Such soap requires shortening, which, in the winter months, has to be effected with salt. Dissolve 10 pounds of salt in 20 pounds of hot water, and gradually add the solution until the soap breaks into white curly roses all over the kettle and "dies off" white. As a rule such soap shows sharpness after adding the salt water. Should this be the case, introduce more palm-kernel oil stirred in water. For the summer months soda or potash solution may be used besides salt, whereby the yield is increased and rapid drying out decreased. This soap being boiled without filling, strong evaporation is not required ; hence, if too much water has been lost by evapora- tion, it is best replaced by diluting the salt solution. These soaps, which are thinly fluid as compared with those filled with water- glass, work very quickly in the frames, and hence, if allowed to stand hot and covered, defective and distorted flux would be formed. They are therefore several times crutched in the frames and tightly covered. Such soaps are decidedly the best as re- gards appearance, are salable as soon as cut, and give a greater yield than can be obtained from the formula by boiling in any other manner. Cocoanut-oil gives more solid soaps and forms a stronger com- bination than palm-kernel oil, also transferring these properties to soaps in the preparation of which it is only partially used or as a combining fat. In half-grain soaps the particles of soap must possess a certain mobility, so that the formation of flux may take place. This is effected by the addition of salt solutions, about 12 per cent, of salt being required when the proportion of cocoanut-oil to other fats is as 7 : 10. By the addition of such large percentage of salt the resulting soap is, however, rendered rough and hard, which is modified by the use of fats of softer consistency. HARD SOAPS. 389 By boiling, for instance, 600 pounds of bone-fat or glue-fat, 200 pounds of cotton-seed oil, 200 pounds of horse-fat, and 700 pounds of cocoanut-oil, soap with a firm cut can be obtained. The boiling to grain is effected in the same manner as pre- viously described, but a different combining lye has to be used, half tank-lye of 24° B. and half caustic soda lye of 28° B. being employed. If the cotton-seed oil is not boiled to grain, the same lye is used for its saponification. For the formula given 450 pounds of tank-lye of 24° B. and the same quantity of caustic soda lye of 25° B. are required. The lye is brought into the kettle together with 5 per cent, of the cocoanut oil of salt (in this case 35 pounds), and after dissolving the grain and soap-cuttings upon it, the larger portion of the cocoanut-oil is introduced with moderate boiling, and the establishment of combination assisted with the crutch. Of the 700 pounds of cocoanut-oil prescribed in the formula, at least 50 pounds are reserved for subsequent correction in fitting. Such soaps, as a rule, rise beautiful and bright, and during ebullition show all the properties of a well- boiling half-grain soap. Salt water should, however, be always kept ready and added in case the formation of a more viscid combination is observed. As above mentioned, such soaps will stand from 10 to 12 per cent, of salt, and it may be added until it is observed to produce an effect by the soap boiling lighter and thinner. If an excess of sharpness is noticed, try to fix it by the addition of the reserved cocoanut-oil, and if this does not suffice add more oil mixed with hot water until the soap boils light and a sample cools slowly. No more carbonated lye than that con- tained in the combining lye is used in winter, though in summer the soaps will stand more of it, calcined soda being frequently scattered over the boiling soap for shortening. Such radical means should, however, be only used when absolutely necessary and water is to be withdrawn from a weak, thin soap. By using the same proportions of fat (10 : 7), with the excep- tion that a portion of the cocoanut-oil is replaced by palm-kernel oil — say 400 pounds of palm-kernel oil and 300 pounds of cocoa- nut oil — the other fats must be taken into consideration if the soap is to be firm in cut and salable. The following formula may serve for the purpose : Bone-fat 390 MANUFACTURE OF SOAP AND CANDLES. 600 pounds, lardaceous fats 200, horse-fat or cotton-seed oil 200, palm-kernel oil 400, cocoanut-oil 300. The process of boiling to grain is the same as for the preceding formulas, the same combining lye being also used, or it might be modified in so far as to take 500 pounds of tank-lye of 24° B. and 400 pounds of caustic soda lye of 24° B. The soap-cuttings and grain are dissolved upon the lye, the cotton-seed oil being boiled at the same time. If the cocoanut-oil is first brought into the kettle, 5 per cent, of salt may be safely added to the lye. As in the preceding process, 50 pounds of palm-kernel oil are reserved and the rest of the operation carried out in the same manner. By sufficiently shortening the soap with salt it is not sharp and remains free from efflorescence in the severest winter, but it must be crutched in the frame. Frequently it lies heavy in the frame, as if cooled too much. This, however, is only de- ceptive, the soap when covered becoming again heated. It is crutched until it shows a temperature of 171.5° F., at which it forms best. For the manufacture of half-grain soap according to the follow- ing formula : Lardaceous fats 400 pounds, bone -fat 600, and palm-kernel oil 700, with about 15 per cent, of water-glass filling, the lardaceous flits and bone-fat are first boiled to grain upon caustic lye of* 13° to 14° B. The combining lye for the palm-kernel oil consists of 200 pounds of tank-lye of 24° B. and 500 pounds of caustic soda lye of 25° B. After dissolving the soap-cuttings and the grain upon the lye, about 100 pounds of water-glass are added and allowed to boil through. Moderate ebullition being kept up, the palm-kernel oil is then introduced, reserving, however, 100 pounds of it. The soap being uniformly boiled through, it is tested whether it has sufficient lye-power to absorb the rest of the palm -kernel oil. If such be not the case, about 2 per cent, of salt (in this case 14 pounds) dissolved in water is added in portions, but never at once. This being boiled through and still no lye-sharpness observed, about 50 pounds of caustic soda lye of 25° B. are added and then the palm-kernel oil. As a rule, half-grain soaps show perceptible sharpness after the addition of salt, a proof that the salt com- mences to act, and hence great care has to be exercised in the HARD SOAPS. 391 farther addition of salt solution. All the palm-kernel oil being in the kettle, and the soap boiling high and light, the fit is so regulated as to shorten either with salt water or carefully using caustic lye of 24° B. Only in rare cases can solutions of the carbonates of the alka- lies be added to such soaps boiled with water-glass, and to judge of the necessity of such addition requires experience. The soap must boil light and break into roses over the entire kettle. The samples must not spread out flat, but when cold still show the rings of the heaping. Half-grain soaps boiled from 1000 pounds of good bone-fat and 700 pounds of palm-kernel oil are also filled with talc. The grain is boiled upon lye of 13° to 14° B., to which about eight per cent, of salt (in this case 80 pounds) is at once added, by which the formation of a paste-soap is prevented, which later on could not be separated by means of salt. Such grain boiled from bone-fat alone, is generally bright and an addition of water is seldom required. The combining lye for the palm -kernel oil consists of 500 pounds of tank-lye of 24° B. and 200 pounds of caustic soda lye of 25° B. If soap-cuttings containing talc are on hand, it is ad- visable first to bring the lye to ebullition, the kettle being cov- ered, and then dissolve the cuttings upon it, this preventing the talc from settling solidly on the bottom of the kettle. The palm- kernel oil is then added, assisting with the crutch and boiling in as thickly as possible. Stir the talc in hot water to a homogene- ous paste and shortly before using it add two per cent, of salt : 100 pounds of talc, 100 pounds of hot water, and 4 pounds of salt dissolved in 20 pounds of hot water constitute the filling. Pour some of the solution over the boiling soap and crutch in so as to effect a uniform distribution as quickly as possible. To a healthy and lightly boiling half-grain soap the filling can only be added with great care, it being necessary to allow the water ad- hering to the talc to evaporate before introducing a fresh portion of the filling, as otherwise the talc falls down and burns fast to the bottom of the kettle, which causes hard dots in the soap. The filling incorporates itself with greater ease in an over-evapo- rated soap, and hence soap lacking water can be improved by it, 392 MANUFACTURE OF SOAP AND CANDLES. the adding of it being interrupted as soon as the soap boils light and high. The fit has now to be tested. If the addition of salt affects the combination, pour melted palm-kernel oil over the soap, and if it becomes thicker more of the filling may be intro- duced. It is impossible to state the quantity of filling half-grain soap will take up, it depending entirely on the quantity of salt- solution it will absorb, because the talc itself is an entirely indif- ferent body towards the soap. From a combination, in which the paste-forming fats are to the others as 7 : 10, a soap firm in cut can also be obtained with 15 per cent, of water-glass. By taking, for instance, 500 pounds of bone-fat, glue-fat, or lard, 200 pounds of cotton-seed oil, sesame-oil, or peanut-oil, 300 pounds of tallow or palm-oil, 400 pounds of palm-kernel oil, and 300 pounds of cocoanut-oil, the 500 pounds of bone-fat and 300 pounds of tallow alone are boiled to grain, while the cotton- seed oil is brought into the kettle together with the combining; lye. If, however, the cotton-seed oil is replaced by sesame-oil or peanut-oil, the latter can be boiled to grain together with the bone-fat and tallow. For combining lye for 400 pounds of palm-kernel oil, 300 pounds of cocoanut-oil, and 200 pounds of cotton-seed oil, about 900 pounds of caustic soda lye of 25° B. are required. The soap-cuttings having been dissolved upon the lye, the cotton-seed oil and the grain are introduced. When the whole is thoroughly boiled through 100 to 130 pounds of Avater-glass are added, and after again allowing the mass to boil up scatter 25 pounds of salt over it, and then add first the cocoanut-oil and next 300 pounds of palm-kernel oil, reserving the remaining 100 pounds for future use. When the soap boils up thick and curly, it is tested as to whether it contains sufficient sharpness to allow of the in- troduction of the reserved 100 pounds of palm-kernel oil, and if such be the case it is added in portions. If on testing the soap the samples are found to become glassy, salt is wanting and has to be added in the form of a solution of 20° B. until the soap loses this property. In doing this sharpness will, however, ap- pear, which is neutralized by the addition of palm-kernel oil. The fit is regulated only after the entire quantity of reserved HARD SOAPS. 393 palm-kernel oil is in the kettle. Such soap must boil high and light, otherwise water is wanting, the addition of which is readily accomplished if weak salt solutions can be used. But if a sam- ple cools off like grain-soap, no more salt solution can, as a rule, be introduced, but the soap will take up water, of which, how- ever, no more than is absolutely necessary must be added. If the water-glass remains unaltered in the soap, sufficient lye is present even if sharpness is not plainly observed. Hardening is effected by salts and light boiling by the addition of water. In case the samples do not heap up in a pile but spread out flat, palm-kernel oil has to be added, though frequently only a small quantity is required. The finished healthy soap boils uniformly over the entjre kettle and breaks into roses up to the rim. If talc is to be used for filling and a portion of the palm- kernel oil to be replaced by cocoanut-oil, fats of a softer consist- ency than bone-fat can be employed, talc filling and tallowy fats giving, in the presence of cocoanut-oil, rough and brittle soaps. The following may serve as a formula : Bone-fat 600 pounds, horsefat 200, cotton-seed oil 200, cocoanut-oil 400, palm-kernel oil 300. The 600 pounds of bone-fat and 200 pounds of horse-fat are boiled to grain upon tank-lye of 13° B., to which four to five per cent, of salt has been added, the result being a light soap from which the lye subsides well. After-grinding with water is seldom required. The combining lye for the above formula consists of 500 pounds of caustic soda lye of 25° B. and 400 pounds of tank-lye of 24° B. The grain, together with the 200 pounds of cotton- seed oil, is first thoroughly boiled upon the lye, the soap- cuttings, if containing talc, are then added, next the cocoanut-oil, and finally 200 pounds of palm -kernel oil, 100 pounds of it being reserved for correction. Boiling is now continued, and in order to introduce salt into the soap, which in any case is too sharp, add the reserved palm-kernel oil and some of the talc liquor. After adding the latter, the soap must improve in appearance and espe- cially boil thicker, otherwise it is too sharp. The principal point, however, is to keep the soap in constant ebullition, crutch-. ing and stirring it and putting off the regulating as long as pos- 394 MANUFACTURE OF SOAP AND CANDLES. sible, until at least 20 per cent, of the filling (in this case about 140 to 150 pounds) is in the kettle. By now pouring melted palm-kernel oil over the soap, by which it is improved, 10 per cent, more of the filling can be added and then the fit regulated. If it is found that water is wanting, the talc liquor can be diluted to double its volume and added in that state. The finished soap must boil thick and break into roses over the entire kettle. The samples should heap up, break like grain-soap, and be entirely white. After resting for one hour in the kettle, the soap should show mottling. It is framed hot, crutched through, and covered when cooled to about 185° F. The formulas for half-grain soaps most used consist of half combining fats and half other fats, provided there be no material difference in the price of the fats. The soaps are filled with car- bonated lye and salt, the yield being about 200 per cent., or under the most favorable conditions, with the use of palm-kernel oil or tallow, 208 per cent. The following formula yields a soap firm in cut : Bone-fat 700 pounds, cotton-seed oil 100, horse-fat 200, palm-kernel oil 1000. The bone-fat or horse-fat or other fats of similar consistency are boiled to grain with tank-lye of 13° to 14° B., or caustic soda lye of 12° to 13° B. The entire quantity of lye (in this case about 1800 pounds) being brought into the kettle, the fire is started or steam admitted. With the use of direct steam, the water of condensation passes into the kettle, diluting the lye. Hence its strength must be increased 1 J° to 2° and a correspond- ingly smaller quantity taken. After adding 5 per cent, of salt to the lye, the fat is introduced, which, by assisting with the crutch, generally saponifies before the mass reaches ebullition. The whole is then allowed to boil through and the wanting: salt added. If the grain formed is round and bright, nothing further is done with it, since, with the kettle tightly covered, the sub-lye sub- sides sufficiently in 10 to 12 hours. It is, however, recommended to ladle the grain into small boxes and allow it to cool. As combining lye for 1000 pounds of palm-kernel oil and 100 pounds of cotton-seed oil, 900 pounds of tank-lye of 24° B., and 200 pounds of caustic soda lye of 24° B. are used. Dissolve the soap-cuttings upon the lye, and after boiling the 100 pounds of HARD SOAPS. 395 cotton-seed oil through with it, add the grain. Now evaporate until a thick grain is formed, then add 900 pounds of the palm- kernel oil, and after having effected a good combination by slow boiling, test the fit. It may happen that a healthy soap, cor- rectly boiling in all proportions, is already in the kettle, which would be due to the carbonates which tank-lye of 24° B. may contain. For the summer months such soap might suffice, but would be unfit for winter, as it would show much efflorescence. By the addition of salt such soap can, however, be improved and rendered free from efflorescence without the further introduction of lye. The salt helps to augment the soap, and liberates suffi- cient lye completely to saponify the reserved 100 pounds of palm- kernel oil. By using the salt, not direct, but as a strong solution, the process is not difficult and is entirely free from danger. By adding to such soap, apparently boiling correctly, only the 100 pounds of palm-keruel oil, at least the same quantity of water or lye would have to be introduced to keep up the right condi- tion of boiling. However, by adding, instead of water or lye, an equal quantity of salt solution, it will be found that the condition of boiling undergoes no change. For the above formula, salt solution of 10° B. will, as a rule, suffice, and as water evaporates by boiling, about 120 pounds of salt solution of 10° B. can be, without injury, used for the 100 pounds of palm-kernel oil. By again testing the fit, especially in regard to the hardness of the soap, complete regulation is very simple. Such soaps should be bright, and while breaking into roses over the entire kettle, not boil thick. In the preceding pages various processes of boiling have been given which are used for the manufacture of half-grain soap from approximately similar fats. While the principal object of the preparatory boiling to grain is to purify and render less odorous impure, badly-smelling, or colored fats, it has also been shown that fats of a tallowy consistency, such as palm-oil, and fats of a lardaceous consistency, such as horse-fat and bone-fat, can also in this manner be worked into half-grain soap with greater ease and profit. An entire series of fats — in fact, nearly all of them — can first be boiled to grain and then used for half-grain soap, but a 396 MANUFACTURE OF SOAP AND CANDLES. better and surer result and greater yield is obtained from them by direct boiling. A smaller proportion of fats than 7 parts to 10 parts of com- bining fat may also be used for indirect boiling, but in this case the process approaches that of direct boiling, as the small per- centage of grain becomes of little importance. We would further mention that impure sedimentary oils containing much stearin — from cotton-seed oil, rape-oil, poppy-oil, sesame-oil, and the sediment obtained by bleaching linseed-oil with lye — cannot be better utilized than for half-grain soap. For the sake of cheap- ness, dark oleic acid and cotton-seed oil can also be worked for half-grain soap, but not more than 50 per cent, of them should be used, even with cocoanut-oil as combining fat. In order to obtain soaps of a firm cut, 40 pounds of cotton-seed oil, oleic acid, etc., may be used for 100 pounds of cocoanut-oil, but only 30 to 35 pounds of linseed-oil. All these oils are boiled upon strong, generally saline, lyes of 20° B., and sedimentary oils con- taining much dirt and water even upon caustic lyes of 25° B. The process of boiling is the same for all. The lye is made boil- ing hot and the oil crutched in. When saponification has appa- rently taken place, i. e., when no more clear oil floats upon the lye, the mass is boiled through for the particles of dirt to sepa- rate and settle as slime upon the bottom of the kettle. It cannot be recommended to use such grain warm, it being best to ladle it into barrels, cover them, and later on draw off the sub-lye from the cold soap. Half-grain soap by the direct method. — The principal and fre- quent defect of half-grain soap is that the ground is not of one color and the mottling does not stand out prominently upon it. A white ground being preferred, a gray or yellowish shade is rendered especially conspicuous with a bright red or blue marbling. In a gray mottled soap a moderately colored ground is frequently quite handsome and makes the soap resemble ordinary full house- hold soaps. Generally speaking, it is, however, absolutely neces- sary to work the fats pure and free from dirt and not too strongly colored, since the particles of color and dirt pass later on into the marbling and destroy the bright and fresh appearance of the color. Impure fats must, therefore, be melted and allowed to HARD SOAPS. 397 settle, and colored fats bleached. Direct boiling being safe and remunerative only with entirely pure fats, those contaminated with acidulated water must be especially rejected. Butchers frequently render the crude tallow with an enormous quantity of sulphuric or hydrochloric acid, and in ladling the melted tallow from the acid water do not particularly care if some of it goes into the barrel together with the tallow. With such material it is next to impossible to prepare faultless half-grain soap by the direct method, especially if water-glass is to be used. As in boiling by the direct method nothing is separated, everything passing into the soap, more attention has to be paid to the lyes than in boiling by the indirect process, and hence this method can only be recommended for factories provided with reservoirs for the previous clarification of the lyes, and besides, with caustic soda lyes of any desired strength. Directly boiled half-grain soaps are much more sensitive than those boiled upon grain, because the salt frequently comes much earlier into use. Recourse to the direct process is, however, absolutely necessary where linseed-oil, cotton-seed oil, or oleic acid is to be worked. The lyes used are similar to those for indirect boiling, consist- ing of tank-lyes of 20° to 30° B., or lyes of the same strength prepared from caustic soda and 30 per cent, calcined soda. More- over, caustic soda lyes of 30° B., and even of 40° B., must be kept ready in case of need, as well as salt solution of 24° B. and soda or potash solution of 30° B. If the preparation of these solutions were left to the time when actually needed, their appli- cation would, as a rule, be too late. In the choice of the combining lyes all the fats worked have to be taken into consideration, it being a principal condition that with the use of cocoanut-oil, palm-kernel oil, linseed-oil, cotton- seed oil, peanut-oil, etc., all of which only saponify with caustic lyes, the boiling is first executed upon caustic lyes as pure as possible, and the required carbonated lye only used later on. We submit the following formula : Lardaceous fats or palm- oil 500 pounds, horse-fat or cotton seed oil 200, bone-fat 200, oleic acid 100, cocoanut-oil 350. For this formula an average lye of about 24° to 25° B. is re- quired — namely, about 800 pounds of tank-lye of 23° B., or of 3D.8 MANUFACTURE OF SOAP AND CANDLES. lye of the same strength prepared from caustic soda lye, with an addition of 30 per cent, calcined soda, and 600 pounds of caustic soda lye of 25° to 30° B. The boiling is generally executed by first bringing the weaker tank-lye into the kettle and allowing the soap-cuttings to dissolve upon it. If any of the fats, such as oleic acid, are to be decolorized or to a certain extent subjected to a preparatory boiling, 200 pounds of caustic soda lye are at once added and the linseed-oil, cotton-seed oil, or oleic acid allowed to boil through with it. The horse-fat and lardaceous fats are then introduced, care being had that a quantity of lye corresponding to the quantity of fat (100 pounds of lye to 100 pounds of fat) boils in the kettle, this facilitating the formation of a correct judgment in case of trouble. If a combination is not formed, add 100 pounds of cocoanut-oil together with 100 pounds of caustic soda lye, and wait, keeping up quiet ebullition, until combination is established. Then add the remaining fats, with the necessary percentage of lye and also the cocoanut-oil, reserving, however, about 100 pounds of it. Even without these 100 pounds of cocoanut-oil, a soap breaking into roses and having a bright, though weak, appearance, must now boil in the kettle. Then add about 2 per cent, of salt, which makes the soap more beauti- ful and facilitates its development. Should, however, the soap, after the addition of the salt, boil thinner or even " wet," add the cocoanut oil together with an equal quantity of water. If a thick, curly soap now boils in the kettle, ascertain by a sample whether sufficient lye is present. With the use of not more than the prescribed quantities of lye nothing can be wanting in a soap boiling faulty except water lost by evaporation, sufficient of which is added until the soap, which should be kept in constant ebulli- tion, boils high and bright. It must, however, not paste, but always boil in lamina? and also break into roses. The fit has also to be frequently tested, because the more water the soap ab- sorbs the more it can be augmented, the augmentation consisting of slightly caustic, saline lye of about 8° B. As a rule, the tank- lye conveys as much carbonate into the soap as required, but in summer it may be necessary to use more, which is recognized by the soap being well-combined and bright. If too much water has been introduced in augmenting with lye HARD SOAPS. 399 so that the soap boils in laminae, it is evaporated until it breaks again into roses, when it may be considered finished. Strong evaporation is not necessary, this soap when fit for cutting pre- senting a better appearance than that with large marble which is strongly evaporated. Marbling, if desired, forms as well in soaps containing water. A formula similar to the preceding, except that palm-kernel oil instead of cocoanut-oil is used as combining fat, consists of: Tallow or palm-oil 600 pounds, bone-fat or horse-fat 300, cotton- seed or linseed-oil 100, palm -kernel oil 450. The boiling lye, which is the same for all the fats, consists of 800 pounds of tank-lye of 23° B. and 600 pounds of caustic soda lye of 25° to 30° B., i. s by the cold process. — The manufacture of soaps by the cold process has already been given in Chapter XV., so that it will only be necessary to give some formulas. Bitter-almond soap is prepared by saponifying 100 pounds of cocoanut-oil with 50 pounds of caustic soda lye of 38° B. and perfuming with 14 ounces of oil of bitter almonds. Essence of mirbane may be substituted for a portion of the oil of bitter al- monds, the quality of the soap being however not as good. Filled bitter-almond soap.— 100 pounds of cocoanut-oil, 50 pounds of soda lye of 38° B., 20 pounds of water-glass com- pounded with 4 pounds of soda lye of 38° B., and 5 pounds of potash solution. Perfume : 14 ounces of essence of mirbane. Honey-soap. — Cocoanut-oil 100 pounds, soda lye of 38° B. 50 pounds. Perfume : Oil of citronella 9 J ounces, cassia-oil If ounces, oil of peppermint 5 drachms, lemon-grass oil 1^ ounces. Color: If ounces of uranin (aniline) orange dissolved in boil- ing water. Honey-soap (filled). — Cocoanut-oil 100 pounds, soda lye of 38° B. 50 pounds, talc 12 pounds, stirred into the warm oil be- fore adding the lye. Perfume : Oil of citronella 7 ounces, cassia-oil 3J ounces, oil of cloves 1 ounce. Color: 2 ounces of uranin (aniline) orange dissolved in boiling water. Bergamot-soap. — Cocoanut-oil 16 pounds, lard 4 pounds, soda lye of 40° 10 pounds. Perfume : Ber^amot-oil 3^ ounces, oil of geranium 11 drachms. Alpine-flower soap. — Saponify 40 pounds of cocoanut-oil and 20 pounds of tallow with 30 pounds of lye of 40° B., and per- fume the soap with 9 drachms of lemon-oil, 5 drachms of rose- 474 MANUFACTURE OF SOAP AND CANDLES. mary-oil, 2J drachms of cinnamon-oil, 6 drachms of oil of peppermint, 5 drachms of oil of sage, and 6 drachms of lavender- oil, dissolving the oils in 8J ounces of alcohol. Color the soap green with a composition prepared from two parts of indigo and one part of picric acid. Bismarck-soap.— Cocoanut-oil 24 pounds, castor-oil 4 pounds, soda lye of 40° B. 14 pounds. Perfume with cinnamon-oil 1\ ounces, oil of cloves 5 drachms, oil of sassafras 8 drachms, oil of bergamot 5 drachms, oil of lemon \\ ounces. Color dark with Bismarck brown. Brown eagle-soap.— -Stir together at 90.5° F. 40 pounds of cocoanut-oil with 23 pounds of lye of 35° B., color with 11 drachms of brilliant brown dissolved in \\ pounds of boiling water, and perfume with 11 drachms of palma-rosa oil and 1 ounce 3 drachms each of essence of mirbane, lavender-oil, and cumin-oil. Pumice-soap.— Ceylon cocoanut-oil 16 pounds, soda lye of 40° B. 8 pounds, pulverized pumice-stone 10 pounds. Perfume with oil of thyme 1 J ounces and oil of bergamot 9.5 drachms. Pumice-soap (another receipt). — Cocoanut-oil 30 pounds, soda lye of 38° B. 30 pounds, water-glass 30 pounds, pulverized pumice-stone 8 pounds, silver sand 34 pounds, indigo 1 ounce. Perfume with 6 J ounces of aniseed-oil. Bouquet-soap. — -Saponify 40 pounds of cocoanut-oil and 60 pounds of lard with 50 pounds of soda lye. Perfume with sassafras-oil 3J ounces, bergamot-oil 5J ounces, rose-oil 2J drachms, oil of lemon 3J ounces, oil of thyme 7J ounces, oil of cloves 1 ounce, oil of neroli 1 \ ounces, and tincture of musk If ounces. Chinese-soap. — Saponify 40 pounds of cocoanut-oil with 20 pounds of lye of 38° to 40° B., and perfume with oil of Por- tugal 1J ounces, oil of bergamot 1J ounces, oil of lemon \\ ounces, tincture of musk 4 ounces, oil of patchouli 2J drachms. Marsh-mallow (atthea) soap. — Saponify 20 pounds each of cocoanut-oil and tallow with 20 pounds of lye of 40° B. Per- fume with oil of lavender 5J ounces, oil of lemon 2 ounces, oil of bergamot 11 drachms, oil of peppermint 1 ounce, oil of neroli 1 J ounces, and color yellow with tompico yellow, or orange with torn pi co orange, or rose-red with brilliant rosa (aniline). MANUFACTURE OF TOILET SOAPS, ETC. 475 Glycerin cold-cream soap. — Melt 25 pounds of cocoanut-oil, 25 pounds of tallow, 8 pounds of castor-oil, and 2 pounds of crude palm-oil, heat to 167° F., and dissolve in the mass 15 pounds of scraps of white or yellow cocoanut-oil soap. Then stir in 30 pounds of lye of 36° B. until the soap-mass becomes thick, and add 1 pound of glycerin and 8 ounces of spermaceti, the last previously heated to 167° F. Now cover the soap, and after allowing it to rest for half an hour crutch thoroughly. After again resting for 1 J hours a thorough combination will be established, which is perfected by a steam or water-bath. A clear yellow solid soap having the appearance of a smooth yellow wax-soap is obtained in this manner. After allowing it to cool somewhat it is brought into the frames and perfumed with cassia-oil 1J ounces, cinnamon-oil 5 drachms, oil of cloves 2 ounces, oil of lavender 3 J ounces, tincture of benzoin 3 J ounces, oil of bergamot 1\ ounces, oil of winter-green 14 drachms, and tincture of musk 3J ounces. Millefleurs-soap. —Saponify 12 J pounds each of cocoanut-oil and olive-oil and 25 pounds of tallow with 25 pounds of caustic soda lye of 40° B., and perfume with bergamot-oil 1J ounces, oils of cloves and of lavender each 1J ounces, oils of cassia and of thyme each 11 drachms, and oil of neroli 5 drachms. Musk-soap. — Saponify 40 pounds of cocoanut-oil with 20 pounds of caustic soda lye of 40° B. Perfume with 3J ounces of tincture of musk, 2 ounces of oil of bergamot, and \\ ounces of oil of lemon. Omnibus-soap. — Cocoanut-oil 200 pounds, lye of 20° B. 275 pounds, common salt and potash each 15 pounds. Perfume with oil of mirbane. Rose-soap. — Saponify 40 pounds of cocoanut-oil with 20 pounds of soda lye of 40° B., color with vermilion, and perfume with bergamot-oil 2J ounces, geranium-oil 2J ounces, and German rose-oil 10 drachms. Vanilla-soap. — Cocoanut-oil 60 pounds, lard 30 pounds, crude palm-oil 10 pounds, pulverized cocoa 12 pounds, caustic soda lye of 39° B. 52 pounds. Perfume with vanilla 1J ounces, balsam of Peru 17 J ounces, oil of lavender 3 ounces, and tincture of musk 1J ounces. 476 MANUFACTURE OF SOAP AND CANDLES. Vanilla-soap (superfine). — Lard with vanilla 30 pounds, cocoa butter 10 pounds, palm-oil 10 pounds, caustic lye of 36° B. 26 pounds, wax 2 pounds, starch 2 pounds. Perfume with tincture of vanilla 4 ounces, tincture of musk 2 ounces, tincture of amber- gris 2 ounces, and oil of rose J ounce. Lard with vanilla is prepared by adding the vanilla to the lard (1 ounce to the pound), keeping it at a moderate heat for some days, straining, etc. Violet-soap. — 63 pounds of cocoanut-oil and 3 pounds of crude palm-oil are melted, cooled to 108.5° F., strained, and colored with 2J ounces of vermilion. Then introduce into the fat through a hair-sieve, with constant stirring, 4 pounds of pulver- ized orris-root, 1 pound of pulverized orange-peel, and J pound of pulverized benzoin. When all the powder is dissolved, sapon- ify the mass with 34 pounds of soda lye of 38° B. and perfume with lavender-oil 2 J ounces, bergamot- oil 2 J ounces, oils of cassia and of cloves, each 1J- ounces, and tincture of musk 2 ounces. The soap need not be colored, it naturally being. of a beautiful brown color. Violet-soap (English). — Tallow 30 pounds, cocoanut-oil 30 pounds, caustic soda lye of 40° B. 30 pounds, carbonated potash lye of 30° B. 1 pound, pulverized orris-root 4f pounds, storax 1J pounds, pulverized orange-peel 1 pound. Perfume : Sambul- root* 3J ounces, musk 2 J drachms, sugar color 1 ounce, oil of sassafras 8 drachms, oil of bergamot 3 ounces, oil of lavender 8 ounces, oil of orange 8 drachms. The pulverized orris-root and orange-peel are sifted into the fat, and the storax, previously dissolved in some hot fat, is then added. The musk is triturated with some sugar, and the sugar color, previously mixed with 4J ounces of water, added. The perfumed color is poured into the lye. The fat is then allowed to cool to 88° F. and the lye heated to 68° F. The soap is not immediately brown, the color as well as the aromatic odor being brought out only after storing for some time. Windsor-soap (brown). — Tallow, cocoanut-oil, and soda lye of 37° B., each 50 pounds, potash solution of 15° B. 4 pounds. Perfume with cassia-oil 7| ounces, oils of cumin, cloves, and * The root of an umbelliferous plant, Euryangium Sambul. MANUFACTURE OF TOILET SOAPS, ETC. 477 lavender, each 1J ounces, oil of thyme 1 ounce, and neroli petit grain 1 J ounces, and color with 1 \ ounces of HessePs leather- brown dissolved in boiling water. Windsor-soap {white). — Saponify 20 pounds each of tallow and cocoanut-oil with 20 pounds of caustic soda lye of 38° B., and perfume with lavender-oil 4 ounces, oil of cumin A.\ ounces, cit- ronel la-oil 14 drachms, fennel-oil 11 drachms, and cassia-oil 3 \ ounces. Toilet-soaps by remelting. — In England the manufacture of toilet-soaps forms a special branch of industry. The manufac- turer, or, to use a trade term, the remelter purchases the various soaps in their raw State from the soap-maker ; these he mixes by remelting, and then perfumes and colors them according to the soap to be produced. The remelter does not confine himself to two or three varieties of soaps, but uses more than eight, mixing three or four for the different toilet-soaps. These soaps are prepared from various fats and are known as Talloiv-soap. — This is a pure, solid, neutral soap prepared from fine tallow and pure caustic soda lye. Oil-soap, as made in England, is a combination of olive-oil and caustic soda lye boiled to grain upon several waters and ground. It is very hard, contains but little water, and is of a greenish color. Castile-soap, as imported from Spain, is also prepared from olive-oil and caustic soda lye, but is colored with sulphate of iron. The solution of this salt being added to the soap after it is manufactured, it is decomposed by the alkali present and ferrous oxide is diffused through the soap, giving it a black, marbled appearance. When the soap is cut up into bars the ferric oxide passes by absorption of oxygen into peroxide ; hence a section of Castile soap shows the outer edge red-marbled, while the interior is black-marbled. Some Castile-soap is not artificially colored, but the marbling is produced by the use of barilla soda contain- ing ferrous sulphide. Palm-soap. — This soap was formerly boiled to grain, but is at present boiled to paste, crude palm-oil and soda lye of about 24° B. being generally used. Yield 220 to 225 per cent. It is gen- erally used for filled toilet-soaps. The odoriferous principle of 478 MANUFACTURE OF SOAP AND CANDLES. palm-oil ? resembling that from orris-root, remains intact in the presence of an alkali, the soap retaining the odor of the oil. Yellow- soap is a cocoanut-oil soap with 20 per cent, of crude palm-oil and 10 per cent, of resin. Marine-soap. — Though the preceding soap is of little value, this is still less so, as it is boiled from cocoanut-oil and soda lye, colored yellow with more or less palm-oil, and is made to yield 400 to 500 per cent. It contains besides a great excess of alkali and much water in combination. White fig-soap. — -Under this peculiar name is understood in England a soft soap prepared from olive-oil and potash, which has seldom a fine, clear, and transparent appearance. The sapon- ification is in most cases defective and incorrect, the soap either containing free, uncombined oil or an excess of alkali. This is also the case with Naples soft soap, which is prepared from fish-oil (mixed with Lucca-oil) and potash. The above soaps constitute the base of all the perfumed toilet- soaps, which are mixed and remelted in the following manner : — The bar-soap is first cut into thin slabs by a wire in the usual manner or converted into shavings. This comminution is abso- lutely necessary, because it would be difficult to melt a bar as a whole, soap being a bad conductor of heat. For remelting kettles of various sizes, holding from 30 to 3000 pounds, are used, and are heated either by a steam-jacket or a water-bath. Fig. 76 shows an improved kettle, for rendering and refining toilet soap, which is manufactured by H. W. Dopp & Son, of Buffalo, N. Y. It is a seamless, steam-jacketed kettle, provided with an agitator so constructed that it can be easily removed from the kettle and swung out of the way when no agitator is required, or for cleaning the machine. A is an upright provided with a rack screwed into a bracket cast on the kettle. A pinion, operated by a hand-wheel, U, en^a^es with this rack, and thus the agitator can readilv be raised out of the kettle. On reaching the top, it can be swung to one side out of the way, and the kettle can be used for boiling and all purposes to which a steam-jacket kettle can be put. The agitator is on the same principle as the remelting crutcher, MANUFACTURE OF TOILET SOAPS, ETC. 479 manufactured by the same firm, and described further on. It consists of a conveyor-screw, D, surrounded by a cylindrical casing, C. By loosening a set-screw, the conveyor-screw D can be withdrawn, and the whole machine can be cleaned very easily. It can be run by hand or power. Fig. 7(3. As the agitator can so readily be taken apart and thoroughly cleansed, and the machine has all the needed facilities for heating or cooling the mass by running cold water through the jacket, this kettle is very useful to soap-makers who make fancy toilet soaps. Fig. 77 shows a remelting crutcher, with engine attached, manufactured by H. W. Dopp & Son, of Buffalo, N. Y., and Fig. 78 the same crutcher without engine. The steam-jacket and inner shell are cast in one piece, having a number of stays between the inner and outer shell, the same as in the jacketed, seamless steam-kettle (Fig. 76); but the re- melting kettle has a large outlet in the centre of the bottom for 480 MANUFACTURE OF SOAP AND CANDLES. the discharge of the contents. A steam-heating radiator, com- posed of a series of cylindrically arranged pipes having open spaces between them, is placed in the centre ; through this radiator steam passes directly to the jacketed part of the kettle, Fisr. 11. which can be cut off from steam supply, so that the inner cylinder only has steam. A conveyor-screw is placed in the centre of this radiator, which surrounds the screw. As soon as a portion of the soap is melted, the screw is set in motion, thereby lifting the MANUFACTURE OF TOILET SOAPS, ETC. 481 soap up, and dumping it over the top of the casing surrounding the screw, and the centrifugal force forces it out of, or through the open spaces left between the pipes. The large scraps are carried up, and are wedged in between the open ports, if we may so call them, at the upper end of the radiator (Fig. 77). The constant motion of the screw shears the pieces off; and thus, in a comparatively short time, the largest scraps are completely cut up, and the whole kettle full of soap will be thoroughly melted and erutehed ready for framing. It should be observed that the transferring of the soap into a crutcher, after remelting the Fig. 78. same, is here overcome, and the two operations are finished in one. Owing to the open spaces left between the pipes composing the radiator, there is no splashing of the soap, soapine, olivine, etc., whatever, as in other machines, however fast the conveyor-screw 31 482 MANUFACTURE OF SOAP AND CANDLES. is worked. Moist steam may be passed at will through the soap- scraps, etc., to moisten them if necessary. Furthermore, if de- sired, cold water may be passed into the jacket and radiator to facilitate the cooling of the soap. The conveyor-screw is worked with a belt and pulley driven by power, and should make about 130 turns per minute. The conveyor -screw may be worked for- ward or backward by merely shifting the clutch that drives the bevel gearing (Fig. 78). The machine is a soap remelter as well as a mixer and crutcher, and is especially adapted for making cold soaps. A fine grade of toilet soap, equal to milled soap, can be made with it in from five to ten hours, and at less than one-fourth the cost. The kettle should be set up sufficiently elevated, so that a soap-frame can be conveniently placed underneath. This may be done either by placing the kettle on a platform of desired height, if the height of the room permits, or by suspending it through the floor above the one on which the soap is framed. When the latter way is chosen, the kettle may either rest on its four side-lugs upon the floor, or it may rest on its top rim or flange, so that it is but little raised above the floor. Be parti- cular that the kettle is set level. It is advisable to use a 4-inch belt, and also to put a steam-gauge in front of the kettle, for which purpose will be found a J-inch gas-pipe hole in T, between valves B and C. Valve B admits steam to the inner cylinder, from which it may be admitted to the jacket by valve D. When valve D is closed, the jacket does not receive steam, but only the water of condensation from the inner cylinder. Valve Cis for the escape of hot water when the machine is used for cooling. Valve F admits steam to the jet-coil used for passing moist steam through the dry scrap to replace water that has evaporated. Of the two one-inch holes in bottom, one is for the escape or waste pipe, the other for the introduction of cold water for cooling purposes. The bent f-irich pipe with air cock is to be screwed into the cor- responding hole in the jacket. It has a branch for a steam- gauge if thought desirable. The small oil-tube and funnel are to be attached to the outlet valve, as shown in cut. If the cold water arrangement is not desired, one hole can be plugged up. Two semicircular wooden covers should be made to fit the top MANUFACTURE OF TOILET SOAPS, ETC. 483 of the kettle. Arrange the handle N, so that it comes to a stop when entirely open, and let it also come to a stop when it is entirely shut, lapping equally over the outlets. There will be found two f-inch tapped holes at the side of the bolts at the bot- tom of the kettle ; also two f-inch studs ; which are to be screwed in to fill the holes. This will set the valve at its proper place, when the handle N is placed in between. In using the kettle, fill it well up with soap-scraps ; turn on the steam, from 5 to 20 pounds steam pressure in the inner cylinder is best adapted for remelting ; too high pressure may, perhaps, scorch the soap. Put on the wooden covers, and turn on the live steam from steam-jet coil by valve F. If desired, the jacket may be cut off from steam supply by closing valve D, or only as much steam as is desired may be used. For this pur- pose the steam-gauge, in communication with jacket, is to be attached. For some soaps this will be necessary, as they are apt to become spongy when lying too long in the hot jacket. The kettle should.be covered during the time that live steam is intro- duced into the scraps, and so long as the crutcher is not running; thus the soap will become more thoroughly moistened, and no steam be thrown into the room. In about fifteen to twenty minutes, the soap will be well melted down : fill up again with more scraps. After a comparatively short time, the covers may be removed, and the crutcher set in motion for a few minutes, so as to mix the melted and the unmelted soap somewhat. Stop the crutcher, and replace the covers, and let the steam and the heat of the jacket, etc. do its work sufficiently, so that the scraps will be almost melted, before attempting to finish the work by crutching. When soap is crutched too much or too long, and, also, when crutched while too thicJc, it 'will become frothy and airy. To avoid this, soap must never be crutched longer than necessary ; it is also necessary that the water lost from the soap since first made be added again to the same by the application of moist steam. In order to obtain the best results in remelting, different qualities of soap-scraps may require a different temperature or pressure in the inner cylinder and jacket of the remelter ; the steam-gauge will always tell how that stands. (Little pressure, less heat ; greater pressure, more heat, etc.) Any man with 484 MANUFACTURE OF SOAP AND CANDLES. common skill and good will will soon master the perfect use of the apparatus. It must not be expected that soap-scraps, after being remelted, will turn out precisely the same as the new soap (from which the scraps were taken) when first made. It must be remembered that soaps, or the scraps therefrom, are under- going a constant chemical change, in the course of time, in their appearance, color, etc. — one quality of soap more, another less. Practical soap-makers who have been using remelters for years advise that, in order to obtain just the desired result in appear- ance, etc. of the remelted soaps, a little filling of some kind or another be added. When the soap-scraps in progress of re- melting have reached that point that, if the unmelted scraps be worked and mixed with the melted liquid soap, a soap will be turned out as thick and no thicker than new made soap, then the moist steam may be turned off, and the crutcher set in motion. Crutch the soap as long as is required to effect a perfect mixings hut no longe)\ To make a toilet-soap equal to milled soap, introduce the soap-scraps and cuttings into the machine, turn on the steam,, proceed as before, but do not use moist steam, as the object is to dry the soap, and run the conveyor-screw slowly. In five to ten hours can thus be produced a soap in every respect equal to a milled soap at less than one-fourth the cost. The bevel gearing of the driving shaft is to be reversed, by shifting the clutch of the gearing, before the finished soap is let out through the bottom valve. The reversing makes the screw run in the contrary way, and thus will force the soap down through the bottom of the kettle. Before reversing the gearing always stop the crutcher;, otherwise you will be sure to break the gearing. When discharg- ing the soap run the conveyor-screw backwards and at a slow speed ; in this Way the soap will be turned out quicker. To ruin at slow speed shift the belt only partly on to the fast pulley. In this way almost any speed from full speed to nothing can be se- cured. Should the soap be found too hot, turn on the cold water while the crutcher is working. When cold water is turned on the steam supply must first be turned off. Be especially careful not to neglect to oil the bevel gearing and the journals thereof; if running dry, they will soon wear, and it MANUFACTURE OF TOILET SOAPS, ETC. 485 will require more power to run the crutcher. When steam is turned on be sure and have the condensed -water discharge-valve at the bottom of the steam-jacket partially open, so that a little steam will ooze out with the discharge- water. When the appa- ratus is not used, have the condensed-water discharge- valve en- tirely open to avoid water collecting in the jacket in case the steam-valve be leakv. Should water collect, it might freeze in Fig. 79. Steam-Jacket Remelter. winter and thus destroy the jacket and the kettle. On first turn- ing on steam open valve D and air-cock of jacket to get rid of 486 MANUFACTURE OF SOAP AND CANDLES. air. After all the air is out valve D must be closed, if no steam is wanted in jacket. After using the machine and before it is cold, blow out jet-coil by opening valve F ; otherwise soap may solidify in the coil and give trouble on next using the machine. A convenient form of a steam -jacketed kettle for remelting soap is shown in Fig. 79. It is provided with a tilting arrange- ment and rests by means of two pivots upon a cast-iron frame secured by screws to a heavy cast-iron base-plate. The steam is admitted by means of a stuffing-box through one of the pivots, and by turning the crank even the heaviest kettle can be readily tilted and emptied without unscrewing the steam-pipe or inter- rupting the admission of steam. Whitaker's patent remelter with continuous coils of steam-pipe is shown in Fig. 80. It can be used for remelting soaps to be E Whitaker's Remelter. converted into toilet-soaps and for remelting scraps, especially of soaps filled with water-glass, sal soda, and other substances. In MANUFACTURE OF TOILET SOAPS, ETC. 487 remelting such scraps by the boiling process all the filling would be lost, which with the immense quantity of filled soap manu- factured at the present time would prove quite a loss. The fol- lowing is a description of the above machine : A, wrought-iron cylinder with dishing-bottom ; B, coil of continuous steam-pipe; C, horizontal scroll-pipe connecting with the upright pipe ; D, wire diaphragm which serves to separate the soap ; E, gate for discharging soap ; F, small pipe for admitting direct steam through perforations into the body of the soap ; K, inlet-pipe and valve for direct steam ; I, inlet-pipe ; and J, discharge-valve for condensed steam; HH, floor of building; G, spout for run^ ning in the scrap. For use fill the remelter with the soap, put on the cover, close the bottom slide, and let on the open steam until the soap begins to melt, which will depend upon the dryness of the soap. When sufficiently melted shut off the open steam ; open the bottom to drain off the condensed steam. Then let on the steam through the coils and put the frames in place to catch the melted soap. When in the frames stir well when half full, and also when full, in order to insure a uniform soap. This machine will hold about 1000 pounds of soap and can be used six or eight times a day. In remelting stock-soaps the shavings are put into the kettle by degrees, or what is technically called "rounds," i. e., the shavings are placed perpendicularly all round the side of the ket- tle, a little water being added at the same time, the steam of which assists the melting. The kettle being covered up, in about half an hour the soap will have melted. Another round is then introduced and so continued until the entire lot of soap is melted. The more water the soap contains the easier it is ruolted ; hence marine-soap or yellow-soap will melt in about half the time re- quired for curd-soap. When different soaps are being remelted to form one kind of toilet-soap, the various soaps are to be put into the kettle in alternate rounds. As the soap melts it is mixed and lumps are broken up by crutching. When the soap is all melted it is col- ored, if required, the perfume added, and after mixing the whole thoroughly by crutching, it is brought into the frames, the sec- 488 MANUFACTURE OF SOAP AND CANDLES. tions of which are frequently made of the width of the intended bar of soap. Almond-soap. — -White tallow curd -soap 100 pounds, oil-soap and cocoanut-oil soap, each 14 pounds, oil of bitter almonds 26 ounces, oils of cloves and caraway, each 8 ounces, or instead of the latter, rose-oil J ounce. It is best, first to melt one-half of the tallow-soap, then the other two soaps, and when they are melted add the other half of the tallow-soap, and finally the perfume. By substituting nitro- benzole (essence 1 , of mirbane) for all or a portion of the oil of bitter almonds, a cheaper soap of not as fine a quality is obtained. Camphor- soap. — -Tallow curd-soap 100 pounds, oil of rosemary 4J pounds, camphor 4J pounds. Reduce the camphor to powder by triturating it with some almond-oil, then sift it. When the soap is ready to be brought into the frame add the camphor and rosemary-oil, with vigorous crutehing. Honey-soap.— -Best yellow-soap 50 pounds, fig-soap 7 pounds, oil of citronella 1J pounds, saffron 1 ounce. Pumice-soap. — White tallow curd-soap 10 pounds, cocoanut-oil soap 3 pounds, finely-pulverized pumice-stone 14 pounds, French lavender-oil 2 ounces, oil of geranium 1 ounce. Sand-soap. — White tallow curd-soap and cocoanut-oil soap, each 7 pounds, fine quartz sand 28 pounds, oils of thyme, cassia, caraway, and French lavender, each 1 ounce. Windsor-soap (old brown). — This popular soap is made in the following manner : Convert 50 pounds each of palm-soap and half palm-soap into shavings and spread upon sheets of strong paper to dry ; when dry melt in a water-bath with a small por- tion of an aromatic water, and when it is hard enough cut into shavings as before, drying it again and remelting and adding sugar color. After the third operation add the following perfume for the 100 pounds : Oil of bergamot 4 ounces, oils of caraway and cassia, each 2 ounces, lavender 8 ounces, cloves and petit grain, each 1 ounce. Brown Windsor-soap owes its fine emollient properties to the amount of labor employed in its manufacture, for it is needless to MANUFACTURE OF TOILET SOAPS, ETC. 489 say that the more soap is worked and handled and melted and remelted the better it becomes. Windsor-soap (brown). — White tallow curd-soap 75 pounds, cocoanut-oil soap, yellow-soap, and oil-soap, each 25 pounds. Perfume with oils of caraway, thyme, cassia, petit grain, cloves, and French lavender, each 2 ounces, and color with \ pint sugar color. Windsor-soap {white). — White tallow curd-soap 100 pounds, cocoanut-oil soap 21 pounds, oil-soap 14 pounds. Perfume with oils of caraway, thyme, and rosemary, each 26 ounces, oils of cassia and cloves, each 4J ounces. French system of maldng toilet-soaps or mMed-soaps. — These are the best and finest toilet-soaps, hence it is of great importance that the so-called stock-soaps used in their preparation should be made from fresh and pure materials and contain no incompletely saponified fats, which would exert an injurious effect upon their durability. They must, therefore, be carefully saponified, salted out, boiled clear, and ground, which will be briefly described further on. Stock-soaps, if allowed to remain too long in blocks after being taken from the frames, readily turn rancid ; hence they should be cut into bars as soon as possible, and these dried in the air or the drying-room. The first operation is to " strip" the stock-soap, i. e., to cut it up into strips or shavings. This may be done either by hand, which is rather a primitive way, though suitable and economical for small lots of soap, or by a machine called a chipper or stripper. The tools required for working by hand consist of an ordinary carpenter's plane and a good marble mortar and pock-wood pestle. Each end of the plane should be provided with a contri- vance, so that when placed over the mortar it remains firm and is not easily moved by the parallel pressure of the soap against the projecting blade. The operation commences by weighing off determined quanti- ties of the soap that is to be cut up and perfumed. The plane is then laid upside down across the mortar and the bar of soap pushed across the plane until it is reduced lo fine shavings. Soap as generally received from the soap-maker is in proper con- 490 MANUFACTURE OF SOAP AND CANDLES. dition for thus working; but if it has been in stock any time it is apt to become too hard, and after having been converted into shavings must be sprinkled with some distilled water and allowed to stand 15 to 24 hours to give the shavings time to absorb the water before the perfume is added. After determining the size the cakes of soap are to be, what they are to sell for, and what they are to cost, the maker can measure out his perfume. The soap being in proper condition in regard to moisture, etc., is now to have the perfume well stirred into it. This is done by working it thoroughly with the pestle for a few hours, when the soap is generally expected to be free from streaks and of uniform consistency. The soap thus perfumed is then weighed out in quantities as required for the tablets and moulded by the hand into egg-shaped masses, which are laid separately in rows on a sheet of white paper, and allowed to dry for a day or two to fit them for the press. It is usual before placing the cakes in the press to dust Fiff. 81. Soap-Stripper or Clipper. them over with a little starch-powder, or very slightly to oil the mould, to prevent the soap from adhering to the letters or em- bossed work of the mould. MANUFACTURE OF TOILET SOAPS, ETC. 4D1 For the preparation of large quantities of toilet-soap it is more convenient and economical to use machinery. The stock-soap is cut into shavings by a machine called a " stripper" and driven either by hand or power. There are four or five different kinds of this machine, though the essential parts of all of them are one or two revolving disks provided with four to six knives and a hopper to contain the bars. Fig. 81 shows such a machine with two disks. Opposite the disks is a hopper or cylinder in which the bars of stock-soap to be stripped are placed. By pressing the bars against the disks, they are cut into shavings which fall through slits in the disks into a receptacle. Fig. 82 is a power-chipper manufactured by Alfred Houchin, of Brooklyn, N. Y. The soap is cut into bars six inches square and, fed into the hopper and the disk, which is a revolving plane, converts it into shavings. The machine can also be arranged for Fig. 82. foot-power by taking off the pulleys and placing a fly-wheel in their place, which is connected to a treadle working the same as a foot-lathe or grindstone. 492 MANUFACTURE OF SOAP AND CANDLES. The latest and most improved machine for this purpose is the automatic soap-chipper manufactured by Messrs. Rutschman Bros., of Philadelphia. This chipper or stripper, Fig. 83, works with great rapidity, and is also adapted for laundry and other purposes. The plate has six knives, which can be regulated to cut the shavings of any thinness and can be cleaned with ease. Fig. 83. Rutschraan's Automatic Soap-Chipper. In working it is only necessary to lay the bars in the trough leading to the knives, as the machine feeds the soap against the knives automatically. After stripping the soap, the shavings are frequently dried somewhat and are then brought into a wooden box lined with zinc or lead. The proper proportions of volatile oils and color- ing matter (except when the soap is required to be white) are MANUFACTURE OF TOILET SOAPS, ETC. 493 first mixed in a separate vessel with a little alcohol, and the mix- ture is then added gradually to the shavings with constant stir- ring. The shavings are then conveyed to the Soap-mill to be blended into a thick homogeneous paste. The mill is similar in construction to a cocoa-mill, and consists essen- tially of three or four contiguous rollers by whose action the Fiff. 84. shavings, color, and perfume are intimately united. The size of the mill, and, whether it is to be worked by hand or steam, de- pends on the size of the establishment. Fig. 84 shows a mill with three rolls to be worked by hand. The rolls are of best syenitic granite finely polished. The perfumed and colored 494 MANUFACTURE OF SOAP AND CANDLES. shavings are brought into the hopper, and after passing through between the first two rolls fall upon the third. A scraper press- ing against the third roll scrapes of! the soap which falls into a receptacle. The milled mass must be returned to the hopper and again passed through the rolls until it is perfectly homogeneous. With a machine with four rolls, Fig. 85, this repeated passing of the milled mass through the rolls is not required, since the operation is effected by the fourth roll. Besides, in large factories Fis. 85. where the work is carried on continuously, two or three machines may be placed alongside each other and the thorough mixing of the mass effected by passing it successively through the machines. The soap-mill manufactured by Rutschman Bros., of Philadel- phia, and shown in Fig. 86, is constructed upon entirely new patterns and principles. The bed is of box-section extending to MANUFACTURE OF TOILET SOAPS, ETC. 495 the ground and on an incline, and with long bearings for the stone rollers, which are made from the best Quincy granite, a material well adapted for the purpose on account of its hardness ; the surface finishing true and smooth, yet porous, so as to grind the soap quickly and perfectly. The shafts, which extend en- tirely through the rollers, are of steel and very heavy, so as to insure against all possibility of springing, and are fastened in the stone rollers with a special device which renders it impossible for them to become loose on the stone. The gearing and all the Fig. 86. Rutschman's Soap-Mill. wheels are either machine moulded or machine cut. The pulleys are of large diameter and breadth and capable of transmitting ample power to the working parts of the machine. The stone rollers are automatically adjusted by a wheel and worm, which 496 MANUFACTURE OF SOAP AND CANDLES. motion is positive, insuring the whole length of the rollers work- ing accurately together, by which the soap is ground thoroughly and rapidly and with the least possible wear on the machine. The mill has a capacity of 250 pounds per hour; power required, 12 horse-power. When a homogeneous mass free from grains and streaks has been formed, the soap is ready for the operation known as " plot- ting" or " peloting," in which the paste is subjected to enormous pressure, sometimes 3000 to 4000 pounds to the square inch, to form it into continuous bars of any shape desired from which cakes may be cut. Various machines called "plodders" are Fi?. 87. Soap-Plodder used for this purpose. Fig. 87 shows a plodder worked by hand, in which the pressure upon the soap in the vertical cylinder is effected by means of a piston. The milled soap is rammed into MANUFACTURE OF TOILET SOAPS, ETC. 497 the cylinder by means of a pestle, and pressure brought to bear upon the contents. The bar (of any shape desired, round, oval, or angular), coming from the discharge aperture, passes on to a table placed in front of the aperture, where it is cut into cakes. Another machine of the same order is provided Avith a mechan- ical ramming and cutting apparatus. The milled soap is simply poured into a hopper over the cylinder. A screw in the cylinder effects the pressure of the sdap, which, passing through a sieve into the discharge aperture, comes out in bars of any desired shape. These machines can be provided with a heating appa- ratus (water, gas, or steam) so as to polish the surface of the bar leaving the machine. Figs. 88 and 89 show a hydraulic plodder. A cast-iron cylin- der serves for the reception of the soap-shavings. The lower end of this cylinder ends in a rectangular channel, B, to Avhich a mould (of any shape the bar of soap is to have) is secured. The aperture of the mould is first closed by a plate, C, to allow of the soap-shavings brought into the cylinder being compressed to a compact mass. With the cylinder A is connected by means of columns the water-cylinder D, in which moves the ram E. The latter and the press-ram i^have a joint piston-rod, G. PTis a pump which, when set in motion by means of the hand-lever J, sucks water from the reservoir iT and conveys it to the cylinder D. A safety- valve, M, inserted behind the delivery-valve L prevents the water-pressure from exceeding a determined limit. As the rams have to be forced up or down by the pressure of the water, the latter is distributed in the box N by means of a slide into the pipes and P, which conduct it to the water-cylinder D. Thus, with the aperture of the mould closed by the lid C, the soap- shavings are compressed into a compact mass and, after the re- moval of (7, forced out as bars. The so-called Boudineuse plodder, constructed by W. Bivoir, is intended for very large establishments. The machine is shown closed ready for work in Fig. 90 and open in Fig. 91. The principal part of this machine is the Archimedean screw-shaft, which possesses a progressive upward motion and is surrounded with a parabolical jacket. By this and an arrangement called 32 498 MANUFACTURE OF SOAP AND CANDLES. Fig. 88. View. Hydraulic Plodder. Fig. 89. Section through Cylinder, A, cylinder ; B, mould ; C, lid ; D, water-cylinder ; E, ram ; F, press-ram ; G, piston-rod ; H, pump ; J, hand-lever ; K, reservoir ; L, delivery-valve ; Jf, safety-valve ; N, distributing-box ; P, pipes. MANUFACTURE OF TOILET SOAPS, ETC. Fig. 90. 499 Boudineuse Plodder, closed. Fig. 91. Boudineuse Plodder, open. " obfcurateur" placed on the aperture, any heating of the perfumed mass of shavings is impossible even with uninterrupted working. The manipulation of changing colors and the mass of soap- shavings and the entire mechanism of this plodder is simplified as much as possible ; it has a capacity of 450 pounds per hour. It is furnished either with cone-pulley or fast and loose pulley. The " Compound Helix Continuous Plodder," patented and 500 MANUFACTURE OF SOAP AND CANDLES. manufactured by Kutschman Bros., of Philadelphia, is shown in Fig. 92. The improvement consists in the feature whereby soap comes continuously from the machine, a variation from the usual style of charging a cylinder with soap and compressing the mate- Fig. 92. Compound Helix Continuous Plodder. rials by means of the hydraulic— a screw or other pressure-— in order to make the soap solid before it can be ran into a bar. The soap is charged in the hopper and comes continuously from the opening in front of the machine (in a bar of any shape de- sired) perfectly solid and entirely free from streaks or other defects. The soap, as soon as it passes through the continuous plodder, can be cut and pressed at once without placing on racks to dry. The construction of the machine is so simple that skilled labor is unnecessary to operate it, It has a capacity of 250 to 350 pounds per hour, the power required being five horse-power. Soap-cutting machine. — Where the plodder is not provided with a cutting apparatus, a special machine for the purpose is required. MANUFACTURE OF TOILET SOAPS, ETC. 501 These machines are of various sizes, and being entirely con- structed of iron, are very durable. The working table (Fig. 93) is smoothly planed. The horizontal wire moves up and down upon two small vertical columns by treading upon the treadle Fig, 93. Cutting Machine. under the table, the counter-weight again raising the wire. A shiftable back-square determines the length of the cakes. The machine being worked by a treadle, both hands are left free, the left pushing the bar forward, while the right removes the cakes. This machine requires but little force, so that it can be run by a girl. Before pressing, the cakes must be heated to facilitate the work and obtain a fine impression, and after pressing the cakes have to be dried. This is effected in a drying-room heated either by a stove or hot air (see page 282). 502 MANUFACTURE OF SOAP AND CANDLES. Soap-presses. — The cakes being sufficiently dry, it is frequently necessary to give them finish, which is often done in a hand-press in a plain mould ; but occasionally a mould-box with hinged Fig. 94. sides is employed, with a screw-press such as shown in Fig. 94. For larger tablets a foot-power press is desirable. Fig. 95 repre- sents a foot-power press manufactured by Messrs. Rutschman Bros., of Philadelphia. It is worked by a treadle, leaving the hands free to handle the soap. It has adjustable balances to vary the blow. It works easily and can be operated by a boy. It is adapted from the smallest size toilet-soap to a two-pound laundry soap. The soap stamping-press, shown together with box and dies in Fig. 96, is manufactured by Alfred W. Houchin, of Brooklyn. This press is adapted for stamping any sized cake of soap, is simple in construction, and adjusted to any sized dies. It has a vertical treadle motion, is easily worked, and gives a direct blow MANUFACTURE OF TOILET SOAPS, ETC. 503 to the soap. The box and dies for stamping soap are made of hard brass, and consist of an upper and lower die fitted to a box, Fisr. 95. which is clamped to the bed of the press, with the bottom die in the box, the top die being fastened to the plunger. The dies can be engraved of any desired size and shape to suit, or can be made with interchangeable plates for the engraving. By this means, different brands of soap can be pressed with the same die by only changing the plate. The improved swing foot-level soap-press, manufactured by H. W. Dopp & Son, of Buffalo, N. Y., is shown in Fig. 97. The slide is provided with two arms, one extending on each side. To these are attached adjustable uprights, b b, which rest on both 504 MANUFACTURE OF SOAP AND CANDLES. ends of the male die to prevent its warping. The press is pro- vided with three lifting bolts, to push the soap perpendicularly Fie. 96. up and out of the mould box. The side bolts a a are connected with the centre bolt by means of a cross head c and set screws. When desired to use the press for ordinary work, the uprights b b and the cross-head may be taken off. This press can be used MANUFACTURE OF TOILET SOAPS, ETC. 505 for pressing a bar of soap from a few ounces up to 3 or 4 pounds in weight and 14 inches long. Fiff. 97. Similar in design is the "steam soap-press, shown in Fig. 98, which is also manufactured by H. W. Dopp & Son, of Buffalo, N. Y. It has a single-acting steam-cylinder placed underneath the bed in such a position that its piston, by means of a roller attached to the end of the piston-rod, acts upon a cam surface of the swing or pendulum-lever, as indicated at B. A hook, A, attached to the piston-rod engages with a stud on the swing or pendulum-lever, and prevents the latter from recoiling after having returned from giving the blow, as it cannot fly back without pulling out the piston. Thus the unpleasant and dan- gerous vibration of the upper die-block is prevented. The 506 MANUFACTURE OF SOAP AND CANDLES. steam-supply pipe enters a governor or regulator which can be set by hand-wheel E> so that the press gives a blow of required Fiar. 98. force. When this has once been set, the press cannot give a stronger blow than that for which it is set, no matter how much steam pressure the boiler may supply. To the right of this governor, JE, is shown a balanced valve steam-trap which drains off all condensed water, and insures the admission of dry steam only to the cylinder, no matter how far the press may be from the boiler. The admission of steam is controlled by a foot- treadle, shown at the right of the cut, the heel of the foot resting on the foot-rest. The handle F serves to control the MANUFACTURE OF TOILET SOAPS, ETC. 507 exhaust in such a manner that the pendulum-lever returns with just enough force to eject the pressed soap, and no more. This ejection of the soap is accomplished by a cam, C, which is pivoted at one end to the pendulum-lever, and clamped to the latter by a jam-nut and arcs. Against this cam works, by means of a roller, a lever which with its other end actuates the centre lifting bolt. By unclamping this cam, shifting it up or down, and reclamping, the height to which the soap is lifted is regulated. This arrange- ment lifts the soap so gradually that there is no danger of throwing the cake of soap out against the upper die-block, and defacing the impression, no matter how fast the press is worked. By throwing back hook A, and raising the foot-rest, the press is at once transformed into an ordinary foot-press. This is a great convenience in setting the die, as well as furnishing means of working when there is no steam. Finishing and polishing the soap-cakes. — The cakes of soap, after they are pressed, stamped, and apparently ready for market, are often dried before being packed. In this drying they may lose some of their lustre. The remedy formerly used for this was to scrape the cakes off, and rub them with a woollen cloth dipped in strong alcohol. This somewhat troublesome process has been superseded, ac- cording to Dupuis, by the method of exposing the soap before or after drying to a current of steam. The steam can be perfumed with any fragrant odor by passing it, before reaching the soap, through a cloth impregnated with fragrant materials. The steam causes at once a change upon the surface of the bars or cakes of soap, and forms, according to the fats used in their preparation, either a super-palmitate or super-stearic palmitin soda combina- tion. If this operation is carefully done it closes up all the pores and uneven spots and, when dry, forms a very lustrous coating, which does not suffer, even under the moulding-press. No other method of polishing will give such a beautiful, even, and lustrous coating as that caused by steaming. Further advantages of this mode of operating are economy in time, manual labor, and pre- vention of all loss. It will especially preserve the soaps in damp storehouses, on sea voyages, and in the show-windows of stores, where they are exposed to the rays of the sun. 508 MANUFACTURE OF SOAP AND CANDLES. Coloring toilet-soaps. — With the many other improvements in the manufacture of toilet-soaps, there has been a corresponding advance in the character aud nature of the coloring so necessary to their attractive appearance. While in former times ochres, chromes, and metallic oxides of iron, as siennas, umbers, etc., were used, with many other mineral substances, the object is now gained by other means, chief among which are the aniline colors. There are, however, necessary but a few primitive colors, as almost any shade can be produced by a suitable blending of them. Thus yellow and orange are made with the naphthaline- yellow or cadmium-yellow ; red is still made with vermilion ; blue with ultramarine ; green with Guinet's green, which is the borate of chrome; browns are made with sugar color, cutch, and chocolate modified with red or yellow. There are also constantly occurring many colors used in dyeing that may find application for soaps, which can, however, only be known by experiment. Of the aniline colors, fuchsin, parmeanilin, eosin, Martius yel- low, Bismarck brown, etc., are used. In coloring soaps it is generally most desirable to color during the process of grinding in the mill, as it has several advantages. It prevents the color from being injured or altered by the heat; it gives the full brilliancy expected from the substance and with much less trouble. Many of the cheaper soaps being cut from the solid and not subjected to the milling and plotting processes, have to be colored and perfumed in the kettle or in the frame. Stock-soaps for milled toilet-soaps. — The stock-soaps are gene- rally prepared from 9 parts of fresh tallow free from odor and 1 part of cocoanut-oil, the addition of the latter securing a more abundant lather. Frequently a larger proportion of cocoanut-oil is used, but the above composition yields the most durable soaps. Suppose 2000 pQiincls of fat are to be converted into stock- soap, the combination would therefore consist of 1800 pounds of tallow and 200 pounds of cocoanut-oil. The fats, which, as pre- viously mentioned, must be entirely pure and fresh, are washed before boiling; with salt water. Combination is next introduced with caustic soda lye of 10° B., and the addition of this lye con- tinued until there are about 1200 pounds of it in the kettle. After the establishment of a thorough combination, boiling is con- MANUFACTURE OF TOILET SOAPS, ETC. 509 tinued with lye of 25° B., of which about 1400 to 1500 pounds are required. Thickening of the soap has to be prevented by a timely addition of lye. After fitting the soap to a slight touch it is salted out, about 10 per cent, of salt being required for the purpose. The soap is then allowed to stand over-night and the next morning the sub-lye is pumped out or drawn off. Sufficient pure water to reconvert the soap to a paste is then brought into the kettle ; the soap is then again fitted to a slight touch with lye of 25° B., salted out, and the sub-lye allowed to subside by standing over-night. The next morning the sub-lye is again re- moved and fresh lye of 20° B. brought into the kettle, the quan- tity depending on the lower width of the kettle, though it must be sufficient for the soap to float upon it and prevent it from scorching. The soap is then boiled clear in the same manner as given for curd-soaps. The next morning the lye is again re- moved and the soap ground with water or weak lye until it flut- ters when thrown with the spatula and the sub-lye begins to become pasty. After standing at least 36 hours in the covered kettle, the soap is brought into the frames and somewhat crutched to promote uniform congealing. For a palm-soap for stock-soap and for toilet-soap we refer to the formulas previously given for palm-soaps, and for this pur- pose advise extra care in selecting the materials. Cocoanut-oil soap for toilet purposes should have a different manipulation. The oil not being saponifiable in weak lyes, it is always necessary to use lyes of 28° to 36° B. They need not be entirely caustic, as this oil can also be saponified with carbonated lye, though it takes, of course, more of it and requires a longer time. For this soap it is now customary to use a portion of lard, cotton-seed oil, or any other white grease or oil, but the cocoanut- oil for toilet-soaps should be the best Cochin China oil. By using a certain proportion of potash lye the soap retains a more plastic consistency and is much improved. White soap from cocoanut-oil. — To prepare 400 pounds of this soap, bring into the kettle 200 pounds of pure white cocoanut-oil and add afterwards 200 pounds of colorless and perfectly limpid lye of 30° B. All being ready, heat the kettle and, to accelerate the combina- 510 MANUFACTURE OF SOAP AND CANDLES. tion of the substances, stir well from time to time. Under the influence of heat the material, which at first was in the form of grains, softens and liquefies. Continue to heat slowly and grad- ually until the combination between the oil and the alkali is effected, which generally takes place when ebullition begins. When properly made the soap has the appearance of a fluid, homogeneous, and syrupy paste. Its color is amber white. It is useless to boil it. Stop off the heat and draw off the soap into the frame. If, on the contrary, it happens, when the mixture begins to boil, that a certain quantity of oil swims on the surface, it may be combined with the saponified mass by adding 10 to 12 pounds of cocoanut-oil soap. The same result may be obtained by adding 8 to 10 quarts of pure water. After stirring a few minutes the homogeneity of the soap is re-established and the combination of the substances perfected. The heat is then stopped and the soap drawn off into the frame. Obtained by the above process the soap is very white, does not contain any excess of alkali or oil, and may be employed for toilet-soaps. From the quantities indicated above, 396 to 420 pounds of soap are obtained, according to the quantity of water added. The operation lasts about one hour. Half palm-soap. — Either of the following formulas may be used : I. White tallow 900 pounds, palm-oil 400, cocoanut-oil 200, yellow resin 100. II. Tallow 700 pounds, palm-oil 300, cotton-seed oil 400, resin 200. III. Lard 550 pounds, tallow-oil 400, cotton-seed oil 450, resin 200. The proportions of these substances are not fixed, and vary according to the uses for which the soap is intended. In Eng- land this soap is prepared with common tallows and an addition of resin. In France, where it is used only for toilet soaps, it is better attended to, and its purification is more complete. The above formulas give a soap of superior quality, and the use of which is very advantageous in the preparation of toilet soaps. The palm-oil may be bleached or not, but must always be purified. MANUFACTURE OF TOILET SOAPS, ETC. 511 The process of preparing the soap is as follows : By a gentle heat, melt the tallow and oils in the kettle ; pour in 100 gallons of new lye of 8° or 10° B. ; heat slowly and gradually, stirring from time to time, and, when ebullition begins, moderate the action of the heat, to avoid a too rapid reaction in the mass. After continuing the ebullition for about four hours, pour little by little on the paste from 35 to 50 gallons of new lye of 15° to 18° B., and incorporate it by stirring for about fifteen minutes. This being done, continue to boil for three hours, or rather until the paste appears quite homogeneous, and has acquired a certain consistency. Then a new quantity of 35 gallons of lye of 20° B. may be added, and, after a new ebullition for two hours, the first operation is finished. Pasting being finished, the heat is stopped off, and after a few hours' rest, pour into the kettle a limpid lye of coction, i. e., salted lye of 20° to 25° B., or a new lye containing salt in solution. While one man pours in the lye, another stirs the paste all the time. When the quantity of salt lye introduced into the kettle is sufficient, the soap is transformed into small grains, and the lye separates abundantly. After resting five or six hours, draw off the lye. About two-thirds of the lyes which have been used are drawn off; they have a yellowish color and mark, when cold, 15° to 16° B. The pasty mass left in the kettle has a fine yellow color. The clear boiling of this soap is very little different from pure palm-oil soap. Like the latter, it is effected with new and caustic lyes of soda of 25° or 28° B. When the operation is done in two services, lyes of 18° or 20° B. are used for the first ser- vice, and lyes of 25° or 28° B. for the second. When, on the contrary, clear boiling is finished in a single operation, lyes of 25° B. are used. This last process is the quickest and most economical. The lyes being drawn off, pour into the kettle from 150 to 175 gallons of new lye of 25° B. ; heat and give a gentle boiling, for in the first hours the soap dilates and swells considerably. Its surface is then covered with an abundant froth, which gradually disappears only as clear boiling progresses. It is necessary to stir from time to time during the whole of the operation. This 512 MANUFACTURE OF SOAP AND CANDLES. agitation is very important, for it accelerates the clear boiling of the soap. When the soap has been gently boiled for three or four hours, the heat may be increased without fear of scorching it. Generally after eight or ten hours of ebullition with lye of 25° B., the soap is completely boiled. The froth has entirely disappeared, or there remains very little on the surface of the soap, which then has the form of hard and dry grains. When these grains are pressed between the fingers, they form thin and hard scales. The resin has been added at the beginning of clear boiling, so as to saponify it completely. When the soap is sufficiently boiled, which is known by its forming scales, stop off the heat, let it rest a few hours, draw off the lye, and proceed to the fitting. Two operations are necessary to completely refine the soap. The first has for its object to soften the grains of the soap, and precipitate the coloring and heterogeneous substances and the excess of caustic lye it contains. When the lye has been drawn off, pour into the kettle 100 gallons of new lye of 8° or 9° B., and heat gradually until boiling, being careful to stir the mixture well. When the grains of soap have become soft, cease the stirring ; and to complete the precipitation of the strong lye contained in the soap, boil for five or six hours, or even eight hours. As by such a long ebullition the grain of the soap has a tendency to be formed again, pour from time to time into the kettle a few pails of lye at 2° B., or even pure water. It is, however, necessary that the soap should be always separated from the lye ; this is ascertained by pouring some of the soap into a glass, and, if so, the lye precipitates to the bottom of the glass. It is important and essential to have, during the whole operation, the lye separated from the soap, to obtain the separation of the strong lye mixed with the paste. When this result is obtained, stop off the heat, and cover the kettle. Let it rest six hours, then introduce the soap into a second kettle, and proceed to a second liquefaction. However great the care taken in the first liquefaction, the soap has not been completely deprived of all its causticity ; it always contains a certain quantity of caustic alkali which must be elim- inated to obtain a pure product. This is the object of the MANUFACTURE OF TOTLET SOAPS, ETC. 5J3 second liquefaction. But to obtain all the good results this operation may produce, substitute for the caustic lyes of soda-ash a non-eaustic solution of crystallized soda. By its extreme purity and the absence of causticity, this solution completely purifies the soap, depriving it of all its caustic parts. Pour into the new kettle about 36 gallons of a solution of crystallized soda of 4J° or 5° B., and heat to a temperature near the boiling point. Then introduce the soap from the first kettle into the second, being careful not to draw off any sub-lye. This being done, boil the mix- ture gently for four or five hours, being careful to stir from time to time. By the ebullition with weak lyes (aqueous solution of crystallized soda), the soap entirely loses its granular appearance, and becomes syrupy, fluid, and homogeneous. As in the first liquefaction, a froth is formed on the surface of the soap, and this froth is more considerable on account of the greater dilata- tion of the paste. As by evaporation the lye concentrates, add from time to time very small portions of water, so as to keep the paste always fluid. The heterogeneous coloring and saline im- purities will be precipitated by resting. The soap must not con- tain too much water, for in this case it would be too long in hardening. The signs by which it is ascertained that the paste is sufficiently liquefied are manifested by a slightly brackish coloration, which proves that the black soap has been precipitated to the bottom of the kettle, and is brought up in the mass by ebullition. When these characteristics are observed, the opera- tion is finished ; stop off the heat ; cover the kettle, and let it rest eighteen or twenty hours. By resting, the black soap preci- pitates with the lye, and the pure soap is between it and the scum. After eighteen or twenty hours' rest, uncover the kettle, and remove the scum from the surface of the soap. Remove the pure soap, and bring it into a frame, passing it through a metallic wire-sieve. All the foreign substances in the soap remain on the sieve. When all the pure soap has been brought into the frames, stir it well until it is cold ; this manipulation is necessary to make it homogeneous. By operating as indicated the above quantities of fatty matters generally give : — 33 514 MANUFACTURE OF SOAP AND CANDLES. Soap scum . 141 to 161 pounds. Pure soap ...... 2100 " 2160 " Black soap . . . . . .500" 600 " The scum and black soap are mixed in the next operation or used for a common soap. The half-palm soap has a very pure yellow color when manufactured with good materials. It has also a good odor and is useful for making many kinds of soap, such as honey, glycerin, marshmallow, etc. The soaps here given may be called stock-soaps, for from them nearly all kinds of toilet-soaps can be formed by compounding diiferent kinds in suitable proportions, milling, mixing, coloring, plotting, moulding, and perfuming to suit the kinds needed. In the following we give a few formulas for milled soaps : — Savon de Guimauve (MarshmaUow-soaj)). — White tallow-soap and palm-oil soap each 40 pounds. Color with yellow ochre and orange mineral each 4 ounces, gamboge 1J ounces, and perfume with oil of lavender 6 ounces, oils of peppermint and caraway each 2 ounces, oik of lemon 1^ ounces, and oils of thyme and rosemary each 10 drachms. Savon a la Hose.- — Tallow-soap 50 pounds, potato-flour 4 pounds. (The potato flour is used to give the soap the necessary consistency.) Color with 7 ounces of vermilion and perfume with rose-oil 1^ ounces, oil of geranium 8 ounces, essence of musk 1J ounces, and essence of civet 1 ounce. Savon aux Fleurs d'ltalie. — White tallow-soap 40 pounds. Perfume with oil of citronella 3 ounces, oil of geranium 1 ounce, oil of verbena 2 ounces, oil of peppermint 5 drachms, and color brown with sugar color. Savon de Crimee.- — White curd-soap 64 pounds, palm-soap 16 pounds. Color with vermilion 10 drachms, brown ochre 4 ounces, ivory black 2 ounces, and perfume with oils of thyme, peppermint, and rosemary each 4 ounces, oil of lavender 10 drachms, oil of cloves 6 drachms, and tincture of benzoin 6 ounces. Savon de pahne. — Palm-soap and half-palm soap each 40 pounds. Perfume with oil of bergamot 8 ounces, oil of cloves 2 ounces, oils of cinnamon and lavender each 4 ounces. Savon a la violette. — Stock-soap prepared from bleached palm- MANUFACTURE OF TOILET SOAPS, ETC. 515 oil 50 pounds, pulverized orris root 4 pounds. Color with terra sterna 1 ounce, and perfume with bergamot-oil 10 ounces, oil of geranium 2\ ounces, oil of neroli 1 ounce,' oil of lavender 1J ounces, essences of civet and musk each 1 ounce. Elder-flower soap. — Half-palm soap 200 pounds, dextrine 6 pounds. Perfume with oil of bergamot 1 pound, oil of lavender 4 ounces, oil of thyme 4 ounces, oil of cloves 2 ounces, and oils of cassia and almonds each 1 ounce, and color light green. Lemon-soap. — White soap 100 pounds, starch 4 pounds. Per- fume with oil of lemon 8 ounces, oils of bergamot and lemon- grass each 4 ounces, oil of cloves 2 ounces, and color yellow with cadmium yellow. Orange-soap. — White soap 100 pounds, starch 4 pounds. Perfume with oil of orange-peel 16 ounces, oil of cinnamon 1 ounce, and oil of thyme 4 ounces, and color dark yellow w T ith napththaline yellow. Patchouli-soap. — White stock-soap 50 pounds, potato-flour 4 pounds. Color with 1\ ounces of Cassel brown, and perfume with geranium-oil 3J ounces, oil of patchouli 7 ounces. Heliotrope-soap. — White curd-soap 80 pounds, palm-soap 20 pounds, starch 4 pounds. Perfume with oil of rosemary 4 ounces, oil of thyme 2 ounces, oil of rose-geranium 3 ounces, oil of cloves 1 ounce, balsam of Peru 3 ounces, and color light purple with a red and blue color. Frangipanni-soap. — Palm-soap 30 pounds, white soap 20 pounds, dextrine 2 pounds. Perfume with oil of bergamot 4 ounces, oils of neroli and santal each 2 ounces, tinctures of vanilla and civet each 8 ounces. Color light brown with tincture of catechu. Cold-cream soap. — White soap 30 pounds, spermaceti-soap 20 pounds, oil of almond J pound, caustic potash of 6° B. 1 pound, gum tragacanth 2 ounces. Strip up the two soaps, place them in the hopper of the mill, dissolve the gum by previous soaking in a little water, mix with the oil and lye to a uniform consistency, then stir in the soap and grind in the mill until thoroughly combined. Care should be taken to have the mass as white as possible. Perfume the above 516 MANUFACTURE OF SOAP AND CANDLES. with oil of bergamot 5 ounces, oils of cloves and nutmeg each 1 ounce, oil of thyme 2 ounces, oil of bitter almonds 1 ounce. Savon de riz. — 54 pounds of wax-soap and 8 pounds of starch. Perfume with oil of geranium 1 ounce, oil of orange (Portugal) 1J ounces, oil of bergamot 1J ounces, oil of mirbane 1 ounce, tincture of benzoin \ ounce. The soap remains white or is col- ored red with 2 \ ounces of vermilion. Savon au bouquet. — White stock-soap 30 pounds. Perfume with bergamot-oil 1J ounces, oil of sassafras J ounce, oil of thyme 6 drachms, oils of lavender and cloves each 5 drachms, oil of geranium 2 drachms. Color yellow, brown, red, or green. Serb-soap (Dr. Borchardtfs).- — White stock-soap and olive-oil soap each 60 pounds, starch 3 pounds. Perfume with oils of cassia and lavender each 1 pound, and oil of bergamot 2 pounds. Lily-soap. — Wax-soap 60 pounds, starch 6 pounds. Perfume with oil of bergamot 5 ounces, oil of geranium 2 ounces, oil of cassia J ounce, oil of santal 3 drachms, oil of cedar, tincture of musk, and tincture of tonka-bean each 1 ounce, tincture of storax 3 ounces. Superfine toilet-soaps. — In the following we give some formulas for fine and superfine soaps, to which it is recommended to add a little wax, which will give to the soaps consistency and smooth- ness and improve their quality. Ambergris-soap. — Grease perfumed with ambergris and musk 25 pounds, jasmine pomade of flowers No. 24 and rose pomade of flowers No. 24 each 10 pounds, beeswax 1 pound, gum traga- canth 3 ounces, caustic soda lye of 33° B. 25 pounds. Color light brown with sugar color. This soap is made of select materials by the cold process, and after being made is allowed a few 'days to dry before milling; the musk and ambergris have to be added to the grease some weeks before, frequently melting and stirring. Benzoin-soap. — Lard with benzoin 30 pounds, cocoanut-oil and tallow, each 10 pounds, soda lye of 35° B. 26 pounds, gum tra- gacanth 2 ounces. Perfume with oil of bergamot 8 ounces, oil of lavender 3 ounces, oil of pimento 1 ounce, flowers of benzoin and tincture of benzoin, each 3 ounces. Saponify in the usual way. The lard with benzoin is made by MANUFACTURE OF TOILET SOAPS, ETC. 517 infusing the lard with the powdered gum (2 ounces to the pound) for a month, occasionally melting and stirring. Melt and strain off the clear lard before using. Jonquille-soap (superfine). — Orange-flower pomade No. 24 20 pounds, tuberose pomade No. 24, jasmine pomade No. 24, and castor-oil, each 10 pounds, white wax 1 J pounds, gum tragacanth 2 ounces, caustic soda lye of 36° B. 27 pounds. Saponify as carefully as possible, avoiding too much heat. The soap will be a light yellow. To enhance the color add a little anatoline. MUlefieur-soap. — Lard with vanilla 20 pounds, lard with am- bergris, rose pomade (aux Hem's) No. 24, and butter of cocoa, each 10 pounds, chocolate 2 pounds, caustic lye of 36° B. 26 pounds. Perfume with oil of orange (Portugal) 8 ounces, oil of lavender 4 ounces, oil of cloves 2 ounces, oil of nutmegs 1 ounce, tincture of musk 4 ounces. The chocolate will give the proper color. Operate with care and you will have a fine soap. Savon a la Marechale (surfin). — Lard with musk and lard with ambrette, each 10 pounds, pomade (aux fleurs) No. 24 of cassia, jasmine, and rose, of each 10 pounds, olive-oil 1 pound, white wax 2 pounds, gum tragacanth 2 ounces, caustic lye of 36° B. 28 pounds. Saponify carefully and color with a little sugar color. Savon hygienique (extra fine). — Orange-flower pomade No. 24 10 pounds, rose pomade No. 24 5 pounds, palm-oil (bleached) 20 pounds, cocoa butter 5 pounds, olive-oil 10 pounds, white wax 1 pound, caustic lye of 38° B. 24 pounds, gum tragacanth 2 ounces. Perfume with oils of santal and geranium, each 2 ounces, oils of valerian and melisse, each 1 ounce, oil of orange 4 ounces, oil of thyme 2 ounces. Avoid too much color ; the soap should have a yellowish-brown that needs no addition. Savon a la violette de Parme. — Violette Pomade No. 24 20 pounds, rose pomade No. 24 and cassia pomade No. 24, each 10 pounds, bleached palm-oil 10 pounds, soda lye of 36° B. 25 pounds, gum tragacanth 2 ounces. Give it a purple color, not too dark. 518 MANUFACTURE OF SOAP AND CANDLES. Lettuce-soap. — Lard with lettuce 20 pounds, cassia pomade No. 24 10 pounds, spermaceti 5 pounds, castor-oil 5 pounds, bleached palm-oil 10 pounds, caustic lye of 36° B. 26 pounds, gum traga- canth 3 ounces. Perfume with oil of bergamot 6 ounces, oil of thyme 2 ounces, oils of valerian and cloves, each 1 ounce. Color light green with Guinet's green. The lard with lettuce is made by melting the lard with its own weight of lettuce leaves, keeping it at the melting-point for some hours, or until the leaves have parted with their color and juice ; then strain off for use. Cucumber-soap. — Operate as for lettuce-soap, using the fruit. Rose-leaf soap (extra fine). — Rose pomade (aux fleurs) No. 24 and lard, each 20 pounds, cocoa'nut-oil 10 pounds, white wax 2 pounds, soda lye of 36° B. 20 pounds, potash lye of 30° B. 12 pounds, gum tragacanth 3 ounces. Perfume with oils of roses, geranium, and bergamot, each 2 ounces, oil of rhodium 1 ounce, oil of cinnamon J ounce, and color light pink with aniline (fast red). Shaving-soaps. — These soaps are prepared in various ways. The properties demanded from a good shaving-soap are, that it yield a good and strong lather, which should remain standing for a long time and at the same time be mild and delicate. To combine these properties fats yielding a good lather have to be chosen and saponified with alkalies exerting a mild effect upon the beard and skin. Hence potash soaps are better adapted for the purpose than soda soaps, and of the latter those containing cocoanut-oil are more suitable than those without it. To obtain a shaving-soap answering all reasonable demands proceed as fol- lows : — Saponify 100 pounds of tallow with lye of 15° B. and boil clear. After removing the salty lye add 15 pounds of cocoanut- oil and saponify it with potash lye of 25° B. When the whole is thoroughly combined, fit the soap slightly, and after allowing it to boil through, bring it into the frame. Perfume with 3J ounces of oil of cassia and \\ ounces of oil of thyme. Shaving-soap by the cold process. — To obtain shaving-soap pos- sessing all the good properties desired it is generally prepared by boiling. It being, however, not always desirable to prepare large MANUFACTURE OF TOILET SOAPS, ETC. 519 quantities at one time, the following process, which will give a good shaving-soap in a short time, is recoui mended : — Bring into the kettle 80 pounds of white tallow and 40 pounds of cocoanut-oil. Heat to about 99.5° F., and the fats being melted, add in the usual manner 64 pounds of caustic soda lye of 30° B. and 16 pounds of potash lye of 30° B., until the mass forms a well-combined, homogeneous paste. The entire operation re- quires at the utmost fifteen to twenty minutes. It is finished when the surface of the soap becomes covered with a film which constantly reforms, notwithstanding stirring. Perfume the soap with oils of lavender and thyme, each 3 J ounces, oil of cumin 7 ounces, oil of bergamot 10J ounces. The perfume is added to the soap, with constant stirring, before bringing it into the frame. Paris transparent shaving soap. — Saponify 20 pounds of castor- oil and 10 pounds of Cochin China cocoanut-oil with 52 to 54 pounds of potash lye of 20° B., and boil like soft soap, until the mass is short, thick, and clear. After cooling to 167° F., add 6 pounds of glycerin, crutch thoroughly through, and then stir in 3 pounds of 90 to 92 per cent, alcohol. Should the soap lose transparency, add water until it is again clear and transparent. Perfume the soap (calculated for 100- pounds) with lavender-oil 5 \ ounces, oil of cumin 3f ounces, and oils of cassia and bergamot, each 1 ounce. Shaving-soap by the warm method. — A good shaving-soap is obtained by saponifying 200 pounds of tallow with lye of 15° B., consisting of 4 parts soda lye and 1 part potash lye, adding the soda lye first and then the potash lye. When the paste is clear, add 40 pounds of cocoanut-oil, together with 15 to 20 pounds of potash lye of 20° B., and salt out, so that the grain appears like ground. Then bring the soap into small frames, and after perfuming it with a few drachms of lavender-oil, add some hot water, and crutch until the soap is cold. English shaving soap. — Pure white tallow, freshly rendered, 40 pounds, Cochin China cocoanut-oil 20 pounds, lye of 30° B., prepared from crystallized soda, 38 pounds ; potash lye of 30° B. 8 pounds. Melt the tallow, and allow the cocoanut-oil to dissolve in it. When all is melted, heat the fat to 144.5° F., stir in the lye, heat again to 144.5° F., and perfume with oil of 520 MANUFACTURE OF SOAP AND CANDLES. bergamot 1J ounces, oil of cumin 2 ounces, oil of Portugal 5 drachms, and oils of thyme and lavender, each 11 drachms. Mix the oils, and add the mixture to the soap before bringing it into the frames. The soap prepared in the above manner has not only a pleasing appearance, but does not contain an excess of alkali, and is, therefore, not only suitable for shaving, but also for toilet use. Windsor soap for shaving. — Pure white tallow 80 pounds, Cochin China cocoanut-oil 40 pounds, soda lye of 30° B. 68 pounds, potash lye of 30° B. 12 pounds. Perfume with oil of bergamot 5 \ ounces, oil of cumin 13 ounces, oil of rosemary 3 ounces, and oil of lavender 3 ounces. Soft toilet soaps.- — The alkaline base of these soaps is potash, and the fatty substance generally used consists of good lard, though sometimes 10 to 20 per cent, of cocoanut-oil is introduced to promote the lathering properties of the soap. The soaps which are generally perfumed with oil of bitter almonds, and are known as almond soap-cream, etc., serve chiefly for toilet purposes and shaving, and must, therefore, be very delicate and mild. Prepare first a clear caustic potash lye of 20° to 21° B. Now bring 50 pounds of white lard and 10 pounds of cocoanut-oil into a clean, roomy kettle ; apply gentle heat, and, when the fat is melted, add 50 pounds of potash lye of 20° to 21° B. ; keep the mixture at a temperature of from 167° to 189° F., and stir constantly. By the action of the heat and stirring, the aqueous portion of the lye is evaporated, and the mixture acquires a thicker consistency. It may happen that a portion of the fatty substances separates from the mass, which is chiefly the case when the temperature of the mixture is raised to a degree ap- proaching the boiling point, because at this temperature concen- trated lyes, with but few exceptions, have, as a rule, little affinity for the fatty substances. It may, however, also be due to the inadequacy of alkali in the mixture. In the first case, the com- bination is restored by moderating the heat, and, in the other, saponification is completed by pouring in a quantity of stronger lye. MANUFACTURE OF TOILET SOAPS, ETC. 521 For the first operation, which is called preparatory boiling, about four hours are required. For the complete saponification of the fat, about 30 pounds of potash lye of 35° B. are then gradually added, care being had to keep the mixture homo- geneous by constant stirring, and keeping the temperature below the boiling point and as stationary as possible between 167° and 189° F. The end of saponification is recognized by the paste acquiring a very thick consistency. Stirring now becoming more difficult, the fire is removed, as, notwithstanding the stirring, the soap might settle on the bottom, and scorch, which would not only change the quality of the soap, but destroy its white color. Many manufacturers prepare this soap in an iron kettle, with double bottom heated by steam ; some use silver kettles, which are preferable, because the soap will retain in them all its whiteness. Fig. 99 represents a kettle with a double bottom heated by steam. This kettle is of tinned cop- per, and may be used also to purify tallow and greases. The entire operation of preparing this soft soap lasts from seven to eight hours. When the soap is cool, it has a soft and pasty consistency, and is poured into large stone or por- celain jars in which it is kept for use. Soft soap, as obtained by the sapo- nification of fatty substances by potash, has not that bright and nacreous appearance required for the toilet. To attain this state, it is ground in a marble mortar, and aromatized with oil of bitter almonds, about 1 ounce being sufficient for the above quantity. Although oil of bitter almonds is principally used as a per- fume for these soap creams, other fragrant substances are occa- sionally employed — for instance, liquid storax and benzoin, oil of cocoa, etc. When the soap is required to be of a delicate rose-color, from 15 to 30 grains of vermilion to each pound of soap must be added and well incorporated with the pestle. 522 MANUFACTURE OF SOAP AND CANDLES. In the following we give a few formulas for various soft toilet-soaps : — Almond shaving cream. — Take a few pounds of the above soap, introduce it into a marble mortar, and strongly triturate it with a wooden pestle. The operation is finished when the soap forms a soft and homogeneous paste ; the more it is beaten, the finer it will become. To perfume it, incorporate from 1^ to 2 drachms of oil of bitter almonds per pound. Rose shaving cream.— Add to the above soap, while triturating it in the mortar, one-half drachm of vermilion per pound, and perfume with attar of roses. Ambrosial shaving cream. — -Perfume with liquid storax and benzoin, oils of bergamot and cloves, and color purple with tinc- ture of archil. Naples shaving cream. — Boiled soft soap 50 pounds, gum tra- gacanth 2 ounces, tincture of musk 2 ounces, tincture of amber- gris 1 ounce, tincture of balsam of Peru 3 ounces, oil of geranium 2 ounces ; color light brown. Shaving-cream.— Melt 20 pounds of hog's lard in a water-bath at 212° F., add with constant stirring 5 pounds of potash lye of 1.33 specific gravity, and keep the mixture at this temperature, gradually adding with constant stirring 5 pounds more of potash lye. Saponification is finished in a few hours. The cooled soap is made into a perfectly homogeneous paste by rubbing in a mortar, and for creme aVamandes perfumed with oil of bitter al- monds, and for creme de rose with oil of rose, and in the latter case colored rose-red. Rypophagon-soap is a mixture of equal parts of resin-soap and fine white soap perfumed with oils of aniseed and citronella. Creme oVambrosie is prepared from lard colored intensely red with alcanna, the finished soap showing a peculiar violet color. It is perfumed with oil of peppermint. Liquid glycerin-soap. — Mix in a suitable vessel 100 parts of oleic acid with 314 parts of glycerin. Heat the mixture and compound it with constant stirring with 56 parts of potash lye of 1.34 specific gravity, whereby saponification is quickly finished. Now allow the soap to stand one to two days, then dilute it with an equal quantity of water, filter, and evaporate the filtrate to MANUFACTURE OF TOILET SOAPS, ETC. 523 half its quantity in a water-bath. To restore the soap to its thickly-fluid, honey-like consistency, add 10 parts of purified potash dissolved in as little hot water as possible. Any desired perfume can be given with oil of neroli or another volatile oil. In this class of soap we include also those which, mixed with water, form emulsions and are used as cosmetics ; they consist chiefly of soft soap, generally almond cream (creme d'amandes) and fat-oil. Amandine. — Mix 2f ounces of white syrup and 11 drachms of almond soap-cream, and gradually add with constant stirring 7 pounds of oil of almond perfumed with 11 drachms each of oils of bitter almonds and bergamot and 5 drachms of oil of cloves. The preparation requires considerable experience and exertion of strength, as towards the end of the operation stirring becomes very difficult on account of the increasing consistency. The fresher the oil the better the preparation. Olivine.— Gum arabic 1 \ ounces, honey 4 ounces, the yelks of 5 eggs, soft soap 2 ounces, olive-oil 2 pounds, oils of limes and bergamot each 11 drachms, oil of thyme 1J drachms, oil of cloves 5 drachms, and oil of cassia 1J drachms. Rub the gum and honey together, then add the yelks of eggs, and add the perfume in the same manner as given for amandine. Glycerin jelly. — Mix 4 ounces of glycerin with 2J ounces of soft soap and stir in, in the manner above described, 4 pounds of almond-oil perfumed with 2J drachms of oil of thyme. In summer it is advisable to use 5 pounds of almond-oil. Soap-balls or savonettes, often called wash-balls, once very much used, are made of any good hard soap, cut into squares and rounded in the hand with a brass tool until spherical. Mottled soap marbled with vermilion and ultramarine is the kind most used. The transparent soaps are also formed into balls and have a good appearance. Medicated soaps. — Every soap-maker engaged in the prepara- tion of medicated soaps is aware of the painstaking care and ac- curacy required to make soaps according to a physician's pre- scription, and although many manufacturers turn out an excel- lent product there are many so-called medicated soaps brought into commerce which do not deserve the name, since they fre- 524 MANUFACTURE OF SOAP AND CANDLES. quently contain not even a trace of efficacious substances. Again., we find other medicated soaps which are inoperative on account of ignorance as regards the decomposition of the chemical agents added to the soap. In many iodine soaps, for instance, a small addition of potassium iodide is found, but no sodium hyposul- phite, which is absolutely necessary to render the iodine effica- cious. And thus there are many other soaps, which from a want of sufficient chemical knowledge are not properly composed, and instead of having a soothing and healing effect in skin diseases promote the diseased state. Medicated soaps are prepared either in the cold or warm way similar to milled soaps. Attention has been recently directed to some medicated soaps prepared by Dr. P. G. Unna, of which the super-fat salicylic- soap and super-fat zinc salicylic-soap are the most interesting. These soaps prepared from the best salicylic acid are successfully used. 1. As a disinfecting soap in all fungoid affections of the skin. 2. As an auxiliary remedy in the form of simple ablutions, with as hot water as possible in severe, obstinate, and strongly itching cases of eczema. 3. In acne, partially to promote the removal of the diseased horny layer and to lay bare the follicle closed by it and partially to remove the black horny points of the comedones. The composition of the Super-fat salicylic-soap is as follows : Super- fat stock-soap 95 parts, salicylic acid 5 parts. The soap is yellowish white and quite soft, and inclined with repeated soaking and drying to be- come brittle, and should, therefore, be kept dry. Super-fat zinc salicylic-soap is composed of 88 parts of stock- soap, 2 parts of zinc oxide, and 10 parts of salicylic acid. This soap is white, very hard, yields little lather with cold water, but an abundant one with hot water, with which it is directed to be used. Other super-fat soaps prepared according to Dr. Unna's direc- tions are :— Super-fat tar-soap contains 5 per cent, of tar. MANUFACTURE OF TOILET SOAPS, ETC. 525 Super-fat sulphur-soap contains 10 per cent, of precipitated sulphur. Super-fat tar-sulphur soap contains 5 per cent, each of tar and precipitated sulphur. Super-fat camphor-sulphur soap with 5 per cent, of camphor and 10 per cent, of precipitated sulphur. Super-fat camphor-soap with 5 per cent, of camphor. Super-fat borax-soap with 5 per cent, of sodium borate. Super-fat iodine-soap with 5 per cent, of potassium iodide. Super-fat naphtholsoap with 5 per cent, of naphthol-jS. Super-fat naphthol- sulphur soap with 5 per cent, each of naph- thoic and precipitated sulphur. Other formulas for medicated soaps. Benzoin-soap. — Cochin China cocoanut oil 16 pounds, soda lye of 40° B. 8 pounds, tinc- ture of benzoin 21 ounces, pulverized sienna 2f ounces. Benzoin soap (in the cold way).- — Prepare first by the cold way a good non-caustic soda-soap from a mixture of cocoanut-oil and lard, strip the soap, sprinkle the shavings with the color, then pour the benzoin tincture over them, mix in the mill, press, dry, and mould the finished soap. For benzoin-soap use : 100 pounds of soap prepared as above and tincture of benzoin 8 pounds. Color brown with sugar color. Benzoin tincture is prepared by treating a good quality of pulverized benzoin with alcohol. Benzoin soap has an agreeable vanilla-like odor. Camphor soap (in the cold way). — Cocoanut-oil 40 pounds, and lye of 38° to 40° B. 20 pounds, stirred together at 106° F., cam- phor 21 ounces, and oils of rosemary and caraway each 7 ounces. The camphor is dissolved in the oil. It may also be dissolved in alcohol and the solution crutched into the finished soap. Carbolic soap. — Half-palm soap 20 pounds, starch 1 pound, carbolic acid (crystals) 1 ounce, oil of lavender 2 ounces, oil of cloves 1 ounce. Carbol-glycerin soap. — Tallow, cocoanut-oil, and lye of 38° B. each 30 pounds, alcohol 1 5 pounds, liquid carbolic acid and glycerin each 12 pounds, sugar color J pound. Prepare in the same manner as glycerin soap. 526 MANUFACTURE OF SOAP AND CANDLES. ^Iodine soap is used for the preparation of so-called iodine baths as a remedy for eruptions of the skin. The soap is prepared in the cold way as follows ; 20 pounds of cocoanut-oil are saponi- fied in the usual manner with 10 pounds of caustic lye of 40° B. and a solution of 3 pounds of potassium iodide in 4 pounds of water is added. Sulphur-soap. — Saponify 20 pounds of cocoanut-oil with 10 pounds of caustic soda lye of 40° B. and stir in 4 pounds of flowers of sulphur. The soap may also be prepared in the following manner : Take any good hard soap, half-palm for instance, and melt care- fully with dissolved starch and add about 12 per cent, of flowers of sulphur, color yellow with naphthaline yellow. Perfume to fancy. Tar-soap).— Melt together 20 pounds of cocoanut-oil and 3 pounds of coal-tar, and saponify the mass with 11 pounds of caustic lye of 11° B. This soap is chiefly used for eruptions of the skin. Another tar-soap is prepared from : Cocoanut-oil 20 pounds, tallow 10 pounds, juniper-tar 5 pounds, soda lye of 40° B. 15 pounds. First saponify the fats and then add the tar ; perfume may be added, though fine perfume would be lost in the strong odor of the tar. Tannin-soap. — Dissolve 15 pounds of good tallow soap in a water-bath, and stir into it 1 pound of tannic acid (to be had of any druggist) and sufficient starch so that the mass can be formed into suitable cakes. Vaseline tar-soap. — Melt 20 pounds of cocoanut-oil and 3 pounds of tar and saponify the mass with 11 pounds of lye of 40° B. Then dissolve 2 pounds of yellow vaseline and stir this together with J pound of lukewarm water into the soap. Thus the intelligent soap-maker can prepare any kind of medicated soap by using the proper proportions of the substances, taking care that the medicinal agent may not be injurious to the skin or the general health. %Thymol-soap with 3 to 5 per cent, of thymol. (Jroton-oil soap with 2 per cent, of croton-oil. Castor-oil soap with 20 per cent, of the oil with other fats, VaAsCaUm jrM • MANUFACTURE OF TOILET SOAPS, ETC. 527 Petroleum-soap with 20 per cent, of the petroleum added to the other fats before saponification. Paraffin soap. — The wax to the amount of 10 per cent, is added to the fats before saponification. Creasote-soap with 2 per cent, of creasote. Turpentine-soap with 5 per cent, of oil of turpentine. Alum-soap with 10 per cent, of finely powdered alum. Mercurial-soap with 6 per cent, of mercurial ointment. Irish moss-soap with 5 per cent, of Irish moss dissolved in a suitable quantity of water and strained. Bran-soap with 10 to 20 per cent, of bran. Cornmeal-soap with 10 to 20 per cent, of cornmeal. Oatmeal-soap with 10 to 20 per cent, of oatmeal. Gall and seouring-soaps. — A good gall-soap for washing fine silk stuffs should not be wanting in any household. Such soap is readily prepared requiring no special apparatus. Cocoanut-oil 6 pounds, tallow 2 pounds, Venetian turpentine 1 J pounds are brought into a kettle and heated to 106° F. Then stir in 4 pounds of caustic soda lye of 38° B. previously mixed with 1J pounds of ox-gall, bring the soap into the frame and cover it lightly. Gall-soap. — Saponify in the ordinary manner 20 pounds of cocoanut-oil with 10 pounds of caustic soda lye of 38° to 39° B. and add 10 pounds of ox-gall. Color green and add 1 J ounces of oil of turpentine. Gall scouring soap. — In 40 pounds of cocoanut oil heated to 99.5° F., dissolve 4J ounces of ultramarine green and saponify in the ordinary manner with 21 pounds of soda lye of 38° B. In the mean while weigh off 6 pounds of potash-lye of 1 0° B. and 8 pounds of salt water of 12° B., stir into this solution 6 pounds of ox-gall and add all with constant stirring to the soap. Then stir in 1 pound of oil of turpentine and 4 ounces of potas- sium bichromate dissolved in 5 ounces of hot water. Ladle the soap into the frame and cover lightly. Scouring soap. — Melt 10 pounds of cocoanut-oil and 6 pounds of kidney-tallow, and saponify with 8 pounds of lye of 40° B. Color the soap green with 1J ounces of ultramarine green, and stir into it 1 pound of ox-gall and J pound of oil of turpentine- 528 MANUFACTURE OF SOAP AND CANDLES. Breslau scouring soap. — Dissolve 2 pounds of white curd-soap cut into fine shavings in 4J ounces of boiling water, and add 3^ ounces of alcohol and 2 ounces of spirit of sal ammoniac. Floating soap. — For certain purposes — bathing, etc.- — it may be of advantage to have a soap which will float. According to Hilgers, such soap can be prepared from every kind of curd-soap by inclosing a sufficient quantity of a substance specifically lighter than water to render the soap itself lighter than water. Hollow glass-balls or hollow substances of water-proof paper are suitable for the purpose, but the best materials are pine-bark, cork, etc., they being light, cheap, infrangible, and indifferent towards the action of water. A piece of bark, cork, etc., cor- responding in shape to the exterior of the cake of soap, and per- forated by several holes, is inclosed in the soap in moulding, an intimate union of the two surfaces being effected by the soap running through the holes in the cork. Instead of inclosing such light substances, floating soap can also be prepared by the formation of actual hollow spaces, im- pressions of any desired shape being made for this purpose upon the inner surfaces of two pieces of soap, which are afterwards cemented together by means of liquid soap. Floating soap can be prepared in a still more simple manner by stirring into hot ground-soap, while cooling, finely pulverized sodium bicarbonate. At a temperature of 158° F., the sodium bicarbonate is decomposed into soda and carbonic acid; and the latter, seeking an escape, renders the soap-mass porous and spongy, in which state it finally cools, its specific gravity being reduced by nearly double the increase in bulk. For preparing floating soap on a large scale, indirect steam has to be used, and the kettle provided with a stirring apparatus. As a rule, fats yielding a good lather, such as cocoanut-oil, palm- kernel-oil, poppy-seed oil, etc., are used. Tallow is not well adapted for the purpose. Scraps from soap prepared from cocoa- nut-oil, etc., may also be utilized. For this purpose, bring, for instance, 200 pounds of water to the boiling point, and dissolve in it 100 pounds of cocoanut-oil soap-scraps, previously reduced to fine shavings by a soap-plane. When all is dissolved, set the stirring apparatus in motion, keeping the contents of the kettle MANUFACTURE OF TOILET SOAPS, ETC. 529 at a temperature of 99.5° F. A thick, viscid lather is gradually formed, amounting to nearly double the quantity of the original mass. Stirring is continued until the lather is thoroughly homo- geneous, which can be readily judged from samples. Shortly before bringing the soap into the frame, it is perfumed with oil of cassia 14 ounces, oil of bergamot 7 ounces, oil of lemon 4J ounces. The soap being completely cooled in the frame, it is cut into bars, and allowed to dry. The soap may be colored as desired. If only white cocoanut-oil soap-scraps have been worked, it is, as a rule, left white, but colored brown if prepared from colored scrap. Floating soap may also be prepared by melting a good quality of wax-grain soap or cocoanut-oil soap in water, and converting the mass into a viscid, thick lather by stirring. The porous soap thus prepared can be perfumed and colored as desired, and possesses the property of floating upon water. 34 {GEORGE J. WHITHED WOBUBN, MASS. 530 MANUFACTURE OF SOAP AND CANDLES. CHAPTER XIX. VOLATILE OILS AND OTHER MATERIALS USED FOR THE PERFUMING OF SOAPS. The volatile oils as found in commerce vary very much in quality, and are frequently adulterated. Unfortunately the means for detecting such sophistications are imperfect and diffi- cult to execute, and it is, therefore, the safest plan to purchase these very expensive articles from a source known to be reliable. In the following we give a list of the volatile oils and other materials best known ; there are, however, many other oils and substances used in perfuming soaps, but they are of minor importance. Oil of bitter almonds is obtained by submitting bitter-almond cake (left after the expression of the fixed oil of bitter almonds) to distillation with water. It is of a pale, golden-yellow color, colorless when rectified, and has a strong nutty taste and odor. Its specific gravity is 1.043 at 59° F., but varies a little with age. Oil of bitter almonds is much adulterated with cheaper oils, but chiefly with nitrobenzole, which has an odor very similar to that of genuine oil. Pure oil of almond mixed with sulphurie acid gives a clear crimson-red color without perceptible decom- position ; with an alcohol f ie solution of potash crystals are elimi- nated. The oil will take up as much as one-third of its weight of iodine, and retain the same in solution. Potassium chromate does not affect the oil. To detect the presence of nitrobenzole, dissolve 1 part by weight of the suspected oil in 10 parts by weight of alcohol; compound the solution with 1.5 parts by weight of solid caustic potash, and evaporate the mixture to one- third its original volume. Pure bitter almond-oil turns brown, but remains fluid, while, if adulterated with nitrobenzole, a brown resinous substance is formed, which floats in the liquid. MATERIALS USED FOR PERFUMING OF SOAPS. 531 Oil of bitter almonds (factitious) known in trade as nitrobenzole, oil of mirbane, essence of mirbane, etc., is now extensively prepared as a substitute for the genuine oil of bitter almonds, and much used for scenting soap, especially the cheaper varieties. It is prepared in the following manner : The apparatus consists of a large glass worm, the upper end of which is divided into two branches, gradually dilating so as to form two funnel-shaped tubes. Concentrated nitric acid is poured into one of the tubes, and benzole into the other. The two substances meet on the point of junction of the two tubes, the rate of flow being regu- lated by suitable means. Chemical reaction takes place at once, and the new compound is cooled by its passage through the worm which is refrigerated for the purpose. The product is repeatedly washed with water, which completes the operation. Nitrobenzole has a specific gravity of 1.209, boils at 415.5° F., and solidifies on cooling to 37.5° F. Bergamot-oil is obtained from the rinds of the Citrus bergamia, or bergamot-orange. It is of a pale green or yellowish color, be- coming, however, darker with age. The specific gravity varies between 0.856 and 0.888 at 59° F. and the boiling point between 365° and 397.5° F. It congeals at 11° F. It is one of the most changeable oils and soon acquires an odor of turpentine. It is frequently adulterated with alcohol, being very soluble in it. The alcohol is detected when it is shaken with red sandal-wood, which with a pure oil is not touched, but in alcohol is colored. From the other oils of the family Aurantiaeece it differs by its ready solubility in alcohol : 1 part of oil in J part of alcohol. Caraway-oil is obtained by distillation from the seeds of the common caraway plant, Carum carui. The oil is nearly colorless, of a very aromatic odor and acrid taste ; it becomes yellow- brownish by age and then shows an acid reaction. It has a spe- cific gravity varying between 0.900 and 0.960 at 59° F., and boils at from 347° to 446° F. It shows but little reaction witli iodine and gives an almost clear liquid with alcohol and sul- phuric acid. Cassia-oil is obtained by distillation from the buds and barks of Cinnamonium eassia, a tree indigenous to China. It is thickly fluid and of a golden-yellow color. Its specific gravity varies 532 MANUFACTURE OF SOAP AND CANDLES. between 1.030 and 1.090. Its fragrance is pleasant and cinna- mon-like, but less refined than the genuine cinnamon-oil under which name it is frequently brought into commerce. Cinnamon-oil (genuine) is obtained from the bark of the young branches of Cinnamonium zeylanieum, a tree cultivated in exten- sive plantations in Ceylon. The oil is heavier than water, its specific gravity being 1.005 to 1.050 at 59° F. It is of a pale- yellow to red-brown color, the latter indicating old oil, of an agreeable odor and biting, but pure sweet taste. It remains liquid at —13° F. Citron-oil, from the peel of the fruit of Citrus medica, or the citron tree. The rectified oil is colorless, of an agreeable, pene- trating odor and acrid taste, and very sensitive to air and light. By exposure to light it turns yellow, and if air be admitted at the same time it is first converted into a fluid, which, on account of its content of ozone, possesses strong bleaching properties. The oil acquires at the same time a disagreeable odor resembling that of oil of turpentine, and is finally converted into a resinous mass. The specific gravity of citron-oil is 0.850 at 59° F., it boils at from 332.6° to 343.4° F., and congeals at —4° F. Citronella-oil is brought into commerce from India and is pro- duced from the leaves of Adropogon Schcenanthus, largely culti- vated in Ceylon. Its odor resembles that of genuine citron-oil. It is chiefly used for scenting the finer grades of honey and yellow soap. Cloves, oil of. — Every part of the clove-tree, Caryophyllus aro- matieus, abounds with aromatic oil, but it is most fragrant and plentiful in the unexpanded flower-buds which are the cloves of commerce. They are soaked for some time in salt water and then submitted to distillation. The oil, when fresh, is al- most colorless, but on exposure to the air acquires a brownish color and a thickly-fluid consistency. It has the aromatic taste and odor of cloves. Its specific gravity varies between 1.030 and 1.080 at 59° F.; it boils at 482° F. It is frequently adul- terated with inferior oils and with carbolic acid. The latter adulteration may be detected by Fliickiger's test as follows : Agitate the suspected oil with 50 parts of hot water ; decant and slowly evaporate the aqueous portion to a small bulk. Add one MATERIALS USED FOR PERFUMING OF SOAPS. 533 drop of ammonia and a very little chlorinated lime. If carbolic acid be present, a green color changing to a permanent blue is developed. Cumin-oil is obtained by distilling the fresh seeds of the cumin, Cuminum cyminum. It is a pale-yellow oil of an aromatic taste and odor. On exposure to air it is rapidly converted into cumic acid. It is lighter than water, its specific gravity being about 0.973 at 59° F. Fennel-oil is derived by distillation from the seeds of the sweet fennel, Fceniculum dulce. When pure the oil is colorless, has a hot, pungent taste, and the odor of the plant. Its specific gravity is 0.940 to 0.997 at 59° F.; it boils at from 365° to 374° F. and congeals at from 39° to 64.5° F. Geranium-oil, also called ginger-grass oil. — The oil of commerce which passes under this name, and which was formerly imported from the East Indies, was not obtained from any species of geran- ium or pelargonium, but probably from a species of andropogon. Properly, however, the term geranium-oil is only applicable to that obtained from some species of pelargonium. The genuine oil from the rose-geranium is prepared in large quantities at La Trappe de Staonelli, not far from the Bay of Sidi Ferruch, in Algiers. A finer oil is yielded by the rose-geranium grown in France and Turkey, but it is much dearer. Geranium-oil smells very much like attar of roses, and is for this reason very fre- quently used for adulterating rose-oil. Jasmin, oil of. — This is obtained from Jasminum officinale and J. grandiflorum. The fresh blossoms of these two jasmine spe- cies are, on account of their small yield of oil, most profitably treated by enfleurage. The oil is pale yellow and possesses a pleasant jasmine smell. Good jasmin-oil deposits at 32° F. jas- min stereopts, which crystallize into lustrous scales which melt at 54.5° F. It is lighter than water and is readily soluble in alco- hol, ether, and oils. Lavender-oil. — The genuine lavender-oil is distilled from the flowers of Lavandula vera ; that produced in England possesses the finest fragrance. "When freshly prepared it is a colorless liquid, which becomes yellow on standing. It has a hot, cam- phorous, slightly bitter taste and an odor of lavender. It has an 4* 534 MANUFACTURE OF SOAP AND CANDLES. acid reaction, a specific gravity of 0.875 at 59° F., and begins to boil at 365° F., the temperature quickly rising to 374° F., and the greater portion distilling over between 383° and 419° F. It is frequently adulterated, chiefly with alcohol, but occasionally with oil of bergamot. The pure oil fulminates quickly and vio- lently with iodine, and sulphuric acid turns it reddish-brown, the reaction being accompanied by strong thickening. An admixture of alcohol is readily detected by treatment with a small quantity of tannin. If the latter is not altered, the oil contains no alco- hol ; if, however, it becomes viscid and sticky, it is adulterated. Adulteration with oil of turpentine is detected by treatment with strong alcohol. For the complete solution of 1 part of oil of lavender 5 parts of 90 per cent, alcohol are required ; if, however, the oil contains turpentine, the fluid is turbid. Another kind of oil of lavender, known as foreign oil of laven- der, to distinguish it from the English oil, or as spike oil, is chiefly obtained by distillation from Lavandula spica and L. stoechas, or Alpine lavenders. This oil, though very good in itself, cannot compare with fine genuine English oil, and brings only about one- tenth of its price. It has a dark-green color and slight lavender odor ; it has an acid reaction, a specific gravity of 0.9081 at 59° F., and begins to boil at from 338° to 347° F. Lemons, oil of, is obtained by various processes from the rinds of lemons. Pure oil of lemons is almost colorless and has the odor of the fruit. Its specific gravity varies between 0.8752 and 0.8785 ; it boils at 148° F., and is soluble in all proportions in absolute alcohol and glacial acetic acid. . It is frequently adulte- rated with turpentine. This may be detected by slowly heating the oil in a dry test-tube with a small piece of copper butyrate to about 338° F., taking care that the temperature does not exceed 356° F. The copper-salt will dissolve in pure oil of lemon with a green color, while in the presence of oil of turpentine a yellow turbid mixture is obtained ; reddish-yellow cuprous oxide being separated. This test is also applicable to oils of bergamot and orange-peels. Limes, oil of, or limette oil, is derived from the rind of the lime, Citrus limetta. The oil is obtained in the .same manner as oil of MATERIALS USED FOR PERFUMING OF SOAPS. 535 lemons, which it somewhat resembles. Its mean specific gravity is 0.8734 at 84° F. Marjoram oil is produced by distilling the flowery tops of the sweet marjoram, Origanum marjorana. When freshly prepared, it is yellowish, but becomes brown by age. It has a pungent smell and a hot, peppery and slightly bitter taste. Its specific gravity is 0.911 at 59° F. ; when distilled it begins to boil at 3(i5° F., but the temperature rises rapidly to 392° F., and remains constant at between 419° and 428° F., a resinous mass being left in the retort. Neroli or orange-flower oil. — This oil, obtained by distillation of the orange blossoms Citrus aurantium, with water, is noted for its fine and fragrant smell and is distinguished over all the other oils of the family Aurantictcece, in such a manner that a falsifica- tion of it seems scarcely possible. It differs, moreover, in its action with nitric acid, by which it acquires a dark red-brown color, while the other oils of the same family of plants are much less colored, some only slightly tinged. Nutmeg-oil (volatile) is obtained by submitting the nutmeg or fruit of Myristica moschata to distillation with water. It is color- less or pale-yellow, and has the odor and taste of nutmegs. Its specific gravity is from 0.920 to 0.948 at 59° F. It is soluble in all proportions in glacial acetic acid. Orange-jjeel oil, also called Portugal-oil, is obtained from the peels of the bitter and sweet orange in a manner similar to that of oil of lemons. It is golden-yellow and has a refreshing odor. Its specific gravity varies between 0.836 and 0.890 at 59° F. ; it boils at 302° F. It is frequently adulterated with both alcohol and inferior oil of other species of citrus. The latter sophistication may be detected by the different behavior of the oils toward alcohol. Genuine orange-oil dissolves only by repeated shaking with 12 parts of its quantity of alcohol, while inferior citrus oils require only 6 parts. If, therefore, 7 to 9 parts of alcohol are required for the solution of the suspected oil, adulteration is proved." With iodine, orange-oil fulminates violently. Patchouli-oil is obtained from the leaves of Pogostemon patchouli. It is of a dark -brown color and its specific gravity varies from 536 MANUFACTURE OF SOAP AND CANDLES. 0.955 to 0.960. Its odor is the most powerful of any derived from the vegetable kingdom ; hence, if mixed in the proportion of volume for volume, it completely covers the smell of all other bodies. It is frequently adulterated to the extent of even 60 per cent, with cheaper oils, mostly those of cedar and cubebs. Pimento oil, or oil of allspice from the bruised fruit of the all- spice, Eugenia pimenta. The oil is pale yellow, becoming reddish- brown by age ; it has a very pungent taste and intense odor resembling that of cloves. Its specific gravity varies between 1.021 and 1.037. The pure oil when treated with nitric acid acquires a red color with strong effervescence. Rose-oil or attar of roses. — -This precious oil is obtained from various species of roses. The principal commercial source of rose-oil is a circumscribed patch of ancient Thrace or modern Bulgaria, where the variety used for distilling purposes is the so- called Thracian rose, a plant of exceedingly rapid growth. The average quantity of product is estimated by Baur at 0.037 to 0.040 per cent. ; another authority says that 3200 pounds of roses give 1 pound of oil. Pure rose-oil, carefully distilled, is at first colorless, but quickly becomes yellowish ; its specific gravity is 0.870 at 72.5° F., its boiling point is 444° F., it solidifies at 52° to 61° F., or still higher, it is soluble in absolute alcohol and in acetic acid. The most usual and reliable tests of the quality of rose-oil are : 1, its odor ; 2, its congealing point ; and 3, its crystallization. The odor can be judged only after long experience. That of the con- centrated oil is intense, penetrating and diffusive, and to most persons unpleasant, the fine and agreeable odor being only brought out by dilution. A good oil should congeal in five minutes at a temperature of 54.5° F., fraudulent additions lowering the congealing point. The crystals of rose-stearoptene are light, feathery, shining plates, and fill the whole liquid. It is evident that such a valuable oil as rose-oil is very much exposed to adulteration. Indeed, it is said that only adulterated oil reaches the market, the sophistication, chiefly with geranium and ginger-grass oil, taking place at the home of the oil. The general characters of these oils are so similar to those of rose-oil, even the odor bearing a distant resemblance, that detection is very MATERIALS USED FOR PERFUMING OF SOAPS. 537 difficult. Greiner recommends the following as a reliable test : Put one drop of the suspected oil in a dry test-tube and add four drops of concentrated sulphuric acid. A perceptible rise in the temperature takes place, and the mixture must be allowed to stand until it becomes cool. Two grammes of absolute alcohol are then to be added and the mixture well shaken. With pure oil the mixture will be slightly opalescent, and, on heating, will turn yellowish brown, the color remaining on cooling the solu- tion. In the presence of ginger-grass, or geranium-oil, the solution will be turbid and an insoluble precipitate soon forms. Pure rose-oil retains its characteristic odor when subjected to this test, but the mixture with the other oils evolves unpleasant odors. When fatty oils, such as sesame, almond, etc., are used as adulterants, the usual test, made by placing a drop on white paper, and heating over an alcohol flame, shows their presence in the greasy stain which remains. Pure rose oil is entirely volatile. The presence of spermaceti, which is usually used for artifi- cially heightening the apparent proportion of stearoptene, is easily recognizable from its liability to settle down in a solid cake, and from its melting at 122° F., whereas the stearoptene fuses at 81.5° F. Rosemary oil is obtained by distillation from the rosemary, Rosmarinus officinalis. It is colorless to pale green, very limpid, and of a more aromatic than sweet odor characteristic of the plant. Its specific gravity is 0.885 to 0.887 at 59° F. ; it boils at from 331° to 334° F., and congeals at from 81° to 86° F. It is frequently adulterated with oil of turpentine; the sophistica- tion can only be detected by the difference of solubility in alcohol. Pure rosemary oil dissolves in an equal volume of 90 per cent, alcohol, while oil adulterated with turpentine requires a far greater quantity for complete solution. Sassafras oil, from the bruised root of the sassafras tree, Sassa- fras officinale. It varies in color from colorless to yellow and red. Its taste is pungent and aromatic, being agreeable to most persons. Its specific gravity varies from 1.070 to 1.090 at 59° F. It is frequently adulterated with oil of turpentine, which is, 538 MANUFACTURE OF SOAP AND CANDLES. however, readily detected by the energetic reaction, and by dis- tilling a sample of the oil. Thyme oil is distilled from the flowering herb of the garden thyme, Thymus vulgaris. It is pale yellow, of an agreeable aromatic odor, and hot, acrid taste. Its specific gravity varies between 0.877 and 0.875 ; it boils at from 302° to 455° F. Vitivert or vetiver oil, from the rhizome of an Indian grass, Anatherum murieatum. It is obtained by distillation either from the fresh root in India, or from the imported dried root. The oil is thickly fluid, of a red-brown color, and has an intense odor very much like that of oil of orris root. Its specific gravity is 0.923 at 59° F ; it boils at 515° F. Whiter green-oil is obtained by distillation from the winter- green, Gaultheria procumhens. The oil found in commerce is generally of a pale-red to deep brown color ; one distillation, however, suffices to discolor it completely. It has both a strong and pleasant smell and a warm, aromatic taste. It is the heaviest of all the essential oils, its specific gravity being 1.18 at 59° F. It boils at from 392° to 430° F. It consists of salicylate of methyl and a small amount of terpene, and can be artificially produced from salicylic acid and methyl-sulphuric acid. Peruvian balsam, according to a report made by Dr. Doret, originates solely from Myrospernum, pereira. To obtain it, the bark of the tree is beaten in four different »pl aces, so that it peels off from the trunk of the tree. A few days after, these places are heated with burning torches, taking the bark away, and placing cloths upon the stripped places, which absorb the oozed- out balsam. These cloths are boiled out in a vessel with water, until they appear entirely free from balsam. The water cooling off, the balsam settles on the bottom. The balsam thus obtained forms a dark-brown, syrupy, opaque liquid, of a very pleasant vanilla or benzoin-like fragrance and aromatic, lasting, taste. It is sometimes adulterated by mixing castor-oil with it. To detect this, distil 10 grammes, shaking the distillate, which consists of two layers, in baryta water, taking off the oil-layer floating upon it by means of a pipette, and shaking it with concentrated solu- MATERIALS USED FOE PERFUMING OF SOAPS. 539 tion of bisulphide of soda. In the presence of castor-oil the shaken balsam congeals forthwith into a crystalline mass. Ambergris. — This is an odorous solid substance found floating on the sea in tropical climates, and in the csecum of the cachelot or spermaceti whale (Physeter macroeephalus). It has been sup- posed by some to be a morbid secretion of the liver and intes- tines analogous to biliary calculi ; but, according to Mr. Beale, it consists of the mere indurated feces of the animal, perhaps some- what altered by disease. The color of ambergris is grayish- white and yellow marbled. It has a pleasant musk-like odor, which is heightened by warming, the odor being peculiar, and not easily described or imitated. It does not effervesce w T ith acids; melts at 140° to 150° F. to a yellowish resin-like mass, and at 212° F. flies off as a white vapor. It dissolves easily in absolute alcohol, ether, and also in fat and volatile oils. A fac- titious ambergris is said to be thus made : Orris powder, sperma- ceti, gum benzoin, of each 1 pound, asphaltum 3 to 4 ounces, ambergris 6 ounces, grain musk 3 drachms, oil of cloves 1 drachm, oil of rhodium J drachm, liquor amnionic 1 fluid- ounce. Beat to a smooth, hard mass with mucilage, and make into lumps whilst soft. Civet — Under this name is known an animal secretion which originates from Viverra zibefha, the Asiatic, and Viverra civetta, the African civet. It separates in these animals from particular glands into a sort of pocket which is situated between the anus and the genital organs and opening outside. The wild animal squirts this mass from time to time spontaneously ; from the ani- mals kept in captivity it is taken with a spoon. Civet forms a smeary, soft, at first white, after a while brownish mass, becoming in time more consistent. It has a peculiar musk or ambergris- like fragrance and a disagreeable, bitter, irritating taste. It melts when heated, puffs up, takes fire, and burns with a bright flame. Mush is a peculiar concrete substance obtained from Moschus mosehiferuSy an animal bearing a close resemblance to the deer in shape and size, and indigenous to the high plateaus of Asia. The 540 MANUFACTURE OF SOAP AND CANDLES. musk is contained in an oval, hairy, projecting sac, found only in the male, situated between the umbilicus and the prepuce. It is from two to three inches long and from one to two broad. In the vigorous male animal the sac contains sometimes 6 drachms of musk, but in the old seldom more than 2 drachms, and none in the young. Musk is in grains or lumps concreted together, soft and unc- tuous to the touch, and of a reddish-brown color resembling that of dried blood. The odor is strong, penetrating, and so diffusive that one part of musk communicates its smell to more than 3000 parts of inodorous powder. The taste is bitter, disagreeable, and somewhat acrid. Musk is very much adulterated, but very little of the genuine article reaching the market. The Chinese are adepts in this so- phistication. Dried blood, on account of its resemblance to musk, is among the most common adulterations, but besides this, sand, iron-filings, hair, the dung of birds, wax, asphaltum, and many other substances are introduced. They are mixed with a small portion of musk, the powerful odor of which is communi- cated to the entire mass and renders the discovery of the fraud sometimes difficult. The bag containing the musk should have the characters before described as belonging to the natural sac and present no sign of having been opened. Genuine musk burns with a white flame and leaves a white, spongy charcoal ; that which burns with difficulty, has a feeble odor and a color either pale or entirely black, feels gritty to the finger, is very moist so as to lose much weight in drying, should be rejected. Tincture of ambergris. — Ambergris (gray) 2 ounces, loaf-sugar 4 ounces, alcohol 8 pints. Tincture of civet. — Civet 2 ounces, orris root (ground) 4 ounces, alcohol 8 pints. Triturate the civet with the orris root in a mortar, adding the alcohol by degrees. Tincture of mush. — -Musk (the best) 2 ounces, sugar 4 ounces, alcohol 8 pints. These tinctures should be kept in a warm place, occasionally stirring for a month properly to extract the odors, which being of animal origin are difficult of solution. SOAP ANALYSIS. 541 CHAPTER XX. SOAP ANALYSIS. In the analysis of soap we have to consider (1) the content of water, (2) the proportion of fatty acid to alkali, (3) the nature of the alkali and of the fatty acid, as well as of resin, and (4) an intentional admixture of organic and inorganic substances. Determination of the content of water. — In the determination of the content of water special care must be had to obtain a fair average sample. The content of water of the outer portions being less than that of the interior, thin cross-sections must be taken from bars of hard soap and the samples of soft soap from the centre of the barrel. In drying soap containing much water, it frequently happens that it melts when exposed at once to a temperature of 212° F. and becomes covered with a film which prevents the escape of the aqueous vapor. To prevent melting together, Loewe recommends first to dry 8 to 10 grammes of the soap, previously reduced to fine shavings at from 140° to 158° F., and then at from 212° to 221° F., until the weight is constant. This is best executed upon a large watch-crystal, which for weighing is covered with another one fitting hermetically. For the determination of water, Gladding recommends to weigh a beaker-glass of about 100 cubic centimetres capacity together with a glass-rod. The bottom of the beaker-glass is to be pre- viously covered 1.3 centimetres high with annealed quartz sand. Then introduce into the beaker-glass about 5 grammes of the soap, weigh again, add about 25 cubic centimetres of alcohol, and heat with occasional stirring over a water-bath until the weight is constant. The loss is water. This method is especially re- commended for soft soap, which it is difficult to get entirely dry by Loewe's process. The exact determination of water in soap being difficult at the best, as the dried soap readily re-absorbs 542 MANUFACTURE OF SOAP AND CANDLES. moisture, many chemists prefer the indirect manner of determin- ing the content of water, L e., they determine all the other con- stituents of the soap and calculate the water from the difference. Salting out has also been proposed for the determination of the dry content of a soap. The weighed sample is brought into a saturated solution of common salt and heated to boiling. The soap balls together to a nearly anhydrous mass, which is weighed after complete drying. The loss in weight gives the original con- tent of moisture as well as that of nearly all other impurities. This method can, however, lay but little claim to accuracy, as the behavior of soaps from different fats towards salt solution varies very much, and, moreover, the separated soap always retains salt, such being largely the case with soaps from cocoanut-oil and palm-kernel oil. Determination of the content of fatty acid. — Take a sample of 6 to 10 grammes, partially from the interior of the bar and par- tially from the exterior, in order to obtain one with the average content of moisture. Place the sample in a porcelain dish, and after pouring 20 to 30 times its weight of diluted sulphuric acid (1 part acid to 12 parts water) over it, heat until the clear fatty acid floats on the surface. From oil-soap the fatty acid separates with greater ease than from tallow-soap, but, as it does not com- pletely congeal, it is difficult to remove without loss, from the fluid beneath. This is overcome by the addition of an accurately- weighed quantity (6 to 10 grammes) of thoroughly dried white wax or stearic acid, which is melted together with the fatty acid, the mass after cooling forming a coherent, hard cake, which can be readily lifted from the fluid by means of a spatula. The cake is placed upon a filter and washed with distilled water as long as the latter takes up sulphuric acid, i. e., shows the reaction with barium chloride. The cake of fatty acid is then dried over sul- phuric acid, quickest in a rarefied space, until the weight remains constant. Now deduct the weight of the wax or stearic acid added from the total weight of the cake. The remainder, in case soap containing no resin is under examination, represents the hydrate of fatty acid and has to be calculated to anhydrous fatty acid. The content of water of the hydrates of stearic, palmitic, and oleic acids being nearly alike, an allowance of 3.25 per cent. SOAP ANALYSIS. 543 will be sufficiently accurate for our purposes. Hence 3.25 per cent, is to be deducted from the weight found, the remainder rep- resenting the anhydrous fatty acid. For the determination of non-saponified fat, mix the finely pulverized sample of soap with sand, and after drying at 212° F. extract it with petroleum ether. The residue remaining after the evaporation of the petroleum ether may consist of neutral fat or hydrocarbons. The presence of the latter might be due to the fats used in the preparation of the soap containing mineral oil, or hydrocarbons having been mixed with the soap. By testing the residue as to whether it is saponifiable or not, its nature is readily established. The statement which is frequently made that the presence of free fat is indicated by the unctuous feel of the soap cannot be relied upon, since soap in the preparation of which cotton-seed oil has been used, shows also an unctuous feel. The question what hinds of fats have been used in the prepara- tion of the soap is very difficult and frequently impossible to answer by the chemist, the only guides being the determination of the melting point, equivalent of saponification and iodine number of the separated fatty acids. The determination of the fatty acid with the assistance of wax or stearic acid, being not available for this purpose, another sample of the soap has to be decomposed by means of acid and the melting point, equivalent of saponification and iodine number of the resulting fatty acids determined by the methods previously given.* Determination of resin. — -The presence of resin is, as a rule, readily recognized by the color and odor of the soap, but the determination of the quantity of it is more difficult. According to Gladding, 0.5 gramme of the fatty acid obtained by decomposing the soap with acid is shaken in a cylinder, graduated to 100 cubic centimetres with 20 cubic centimetres of 95 per cent, alcohol until all is dis- solved. The solution is then compounded with one drop of phenol-phthalein solution and after adding concentrated potash- lye until the alkaline reaction takes place, heated in a water-bath. After cooling the cylinder is filled up to the 100 cubic centi- metre mark with ether, and, after shaking, 1 gramme of dried * See pp. 85, 90, and 91. 514 MANUFACTURE OF SOAP AND CANDLES. and pulverized nitrate of silver is added, and the whole shaken until the precipitate balls together in a manner similar to chloride of silver. After allowing the precipitate consisting of silver salts of fatty acids to subside, 50 to 70 cubic centimetres of the super- natant clear fluid are brought by means of a pipette into a cylinder graduated into 100 cubic centimetres and shaken with a very small quantity of nitrate of silver, in order to be sure that everything has been precipitated. If a precipitate is formed, it is best to commence the test anew. If there be no precipitate, shake with 20 cubic centimetres of dilute hydrochloric acid (1 part acid, 2 parts water) and after allowing the chloride of silver to subside read off the height of the ether-layer. Then bring an aliquot part of the layer of ether into a platinum dish, evaporate to dryness, dry at 212° F., and weigh the residue which is brought into the calculation as resin. According to Gladding, a small correction of 0.002359 gramme for every 10 cubic centimetres of the solution can be made for the small quantity of oleic acid which has passed into solution. Determination of alkalies. — The alkali contained in soap is either potash or soda, or a mixture of both. To determine the kind of alkali, separate the fatty acids from a solution of soap and test with alcoholic solution of chloride of platinum which, in the presence of potassium, gives a yellow precipitate. The quan- titative determination of the alkalies, if only one be present, is effected by the alkalimetric method. Decompose the soap with an excess of normal acid, and after allowing the fatty acids to separate, determine the quantity of acid added in excess by retitrating with caustic alkali. The difference gives the quantity of acid used for the neutralization of the alkali of the soap and from it the quantity of the alkali itself is found. If the decom- position of the soap is not readily effected by the acid, add some spirit of wine, which dissolves the soap and facilitates its decom- position. Heating or boiling should by all means be omitted. If both potassium and sodium are present, the total quantity of alkali is alkalimetrically determined in one sample, while a second sample is decomposed with hydrochloric acid and the potassium in the solution determined with chloride of platinum. SOAP ANALYSIS. 545 The sodium is then calculated from the potassium found and the total quantity of alkali. The following method may also be used for determining the alkalies : The quantity of soap weighed off is brought into a platinum crucible and after carefully incinerating the organic substance, the ash is treated by the alkalimetric method. For ordinary purposes it is sufficient to give the entire content of alkali calculated from the titration as sodium oxide (Na 2 0) for hard soaps and as potassium oxide (K 2 0) for soft soaps. Whether a soap contains free alkali, i. e., caustic alkali or carbonate is recognized by the addition of a small quantity of phenol- phthale'in to an alcoholic solution of the soap which produces a red coloration ; further by dropping upon the freshly-cut surface of the soap a small quantity of solution of mercuric chloride, which produces a yellow coloration, or a small quantity ot mercurous nitrate, which gives a black coloration. The test with mercuric chloride is, however, not always reliable. For the determination of non-saponified alkali, boil the weighed- off sample with distilled water, and introduce common salt in small portions into the solution. The soap coagulates and sepa- rates out, while the non-fixed alkali remains in the salt solution. Now continue the addition of common salt until the last portions added do not dissolve. Then bring the salt solution into a beaker glass, and, after adding the wash-water used in freeing the soap from adhering saturated salt solution, determine the quantity of alkali by the alkalimetric method, having previously ascertained its presence with curcuma paper or litmus paper. Determination of glycerin. — Dissolve about 25 grammes of the soap to be examined in hot water, and compound the solution with dilute sulphuric acid until acid reaction takes place. Then melt the fatty acids together with wax, and, after cooling, lift off the cake of fat, and evaporate the fluid previously exactly neu- tralized with sodium carbonate to dryness in a water-bath. Treat the residue, consisting of sodium sulphate and glycerin, with al- cohol, whereby the sodium sulphate remains undissolved behind. Then evaporate the alcoholic solution; again treat the residue with alcohol, and evaporate the filtered solution in a platinum dish in a water-bath. Great accuracy cannot be claimed for this 35 546 MANUFACTURE OF SOAP AND CANDLES. method on account of the volatility of the glycerin. For a more accurate determination of the glycerin, dissolve, according to the suspected content of glycerin, 1 to 10 grammes of the soap in water, or, if organic substances insoluble in water be present, in methyl alcohol. Filter the solution, and after evaporating the methyl alcohol, if used, separate the fatty acid, and then proceed with the acid filtrate in the same manner as for the determina- tion of glycerin in fats. Determination, of alcohol. — Transparent soaps being, at the pre- sent time, prepared with alcohol as well as without, it may some- times be important to know whether a soap contains alcohol. For its determination, mix, according to Valenta, 50 to 60 grammes of the soap to be examined with pumice stone, and distil in a paraffin-bath, first at 230° F. and then at 248° F. With the distillate the iodoform test is made, which is executed, according to Hager, as follows : The fluid to be tested is com- pounded with 5 to 6 cubic centimetres of a 10 per cent, potash solution, and after heating to from 104° to 122° F., 16 to 20 per cent, potassium iodide solution saturated with iodine is added until the fluid assumes a yellow-brownish color. If the color does not appear on shaking, add by means of a glass-rod just sufficient potash lye entirely to decolorize the fluid. Imme- diately, or after standing a short time, yellow crystals of iodo- form are separated out, which, when viewed under the micro- scope, present a star-like appearance, or one of hexagonal tablets. Determination of volatile oils. — The separation of volatile oils used for perfuming soaps can, according to Barfoed, be effected by two methods. Extract the soap at an ordinary temperature with ether, filter through a filter moistened with ether, and rinse off with the same liquid. Shake the solution with water to remove any soap which may have passed into it, and then evap- orate; or dissolve the soap in water, compound the solution with a small quantity of sulphuric acid to prevent strong foam- ing, and distil off the volatile oils. From the distillate the oil is collected by shaking with ether. Determination of filling agents. — The filling agents are partially salts soluble in w T ater, especially the chlorides and sulphates of potassium and sodium, the alkaline carbonates and water-glass, SOAP ANALYSIS. 547 partially mineral substances soluble in water, such as talc, heavy spar, infusorial earth, etc., and partially organic substances, such as potato flour. For the determination of admixtures, dissolve the soap, previously cut into fine shavings, in 8 to 10 times its quantity of 90 per cent, alcohol by moderate heating in the water-bath. Then filter the solution, and, after washing the residue with alcohol, and drying at 212° F., weigh it. Trans- parent soaps prepared with the assistance of spirit of wine alone are soluble in alcohol without leaving a residue. For determining the portion of the residue soluble in water, ex- tract it with cold water, and after reducing it to a determined volume, take portions of it for determining the sulphuric acid, chlorine, silicic acid, and the alkalies. In the absence of water- glass, the carbonic acid fixed on alkalies can only be determined by titration, direct determination of the carbonic acid being otherwise preferable. A content of water-glass can also be de- termined by dissolving the soap in water, and compounding the solution with an acid. The fatty acids float on the top, while the silicic acid falls to the bottom, or remains suspended in the fluid. It is collected upon a filter, washed, dried, heated, and weighed. Soap containing water-glass yields free alkali to spirit of wine, while the silicic acid remains behind as a jelly. By boiling the portion insoluble in alcohol with water, a thickish solution is formed in the presence of starch, which ac- quires a blue coloration on adding a few drops of tincture of iodine. To test for glue, extract the portion of the soap insoluble in alcohol with hot water. The solution gelatinizes on cooling, and yields a precipitate on compounding it with solution of tannic acid. Mineral oils and mineral fats can be readily deter- mined by being non-saponifiable. For the determination of tale, heavy spar, infusorial earth, etc., heat the residue insoluble in water in order to destroy the organic substances, and then test it as to its constituents. Prof. Albert R. Leeds's scheme for the analysis of soap. — (1) Water : Weigh out about 5 grammes in very fine, small shavings upon a dried, weighted, plated filter. Dry at 230° F. until the weight is constant. The loss is water. (2) Uricombined fat : 548 MANUFACTURE OF SOAP AXD CANDLES. Transfer the filter containing the dried soap to the funnel con- nected with the return-cooler,- such as is used in the determina- tion of the albumenoids in milk, and connect with the funnel a small tared flask containing 50 cubic centimetres of petroleum ether. After complete extraction distil off the ether, and the residue in the flask, dried at 230° F., will be the uncombined fat. (3) Free alkali, (4) Glycerin : Allowing the funnel, with the soap freed from moisture and from fat, to remain on the return- cooler, attach to it a flask containing 75 cubic centimetres of 95 per cent, alcohol, and extract. To the alcoholic solution add a few drops of phenol-phthalein ; if free alkali be present, neu- tralize with normal sulphuric acid and calculate the amount of uncombined soda. After neutralization add a large excess of water and boil off the alcohol. To the aqueous solution add a large excess of normal sulphuric acid. Boil, cool, and decant through a small filter, wash with hot water, and decant, after cooling, through the filter until litnius-paper is no longer red- dened by the washings. The filtrate consists of the combined soda and glycerin, the residue of the fatty acids, and resin. Neutralize the filtrate with normal soda solution and calculate the amount of combined soda as Xa 2 0. Evaporate to dryness and extract the glycerin with absolute alcohol. Transfer the alcoholic solution to a tared flask, distil off the alcohol, dry at 212° F., and weigh the residue as glycerin. (5) Fatty acids and resin: Dissolve the small amount of the fatty acids and resin that mav be on the filter, through which the decantation was effected, with a little petroleum ether, add the solution to the larger bulk in the beaker, evaporate off the ether, dry at 212° F., and weigh the combined fatty acids. Multiply this result, after subtracting the amount of the resin, by 0.97, and the product is the fatty anhydrides. (6) Fesin : The resin was separated from the fatty acids according to the methods proposed by Gladding. About 0.5 gramme of the mixture of the fatty acids and resin is dissolved in 20 cubic centimetres of strong alcohol, and with phenol-phthalein as an indicator, soda is run in to a slight super- saturation. The alcoholic solution, after boiling for ten minutes to insure complete saponification, is mixed with ether in a gradu- ated cylinder till the volume is 100 cubic centimetres. To the SOAP ANALYSIS. 549 s e o to 33 !<. o t>» cc « X) ^ © 05 ti to ■a ^ 33 bfl ^ >o * © ,3 be 33 u - 73 3,3. 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H -Ofl« "^ & d«3s^-- Sjjj .1— T3 ~) T* *^> x * « J n ^ hr "' 2 3 2 " O-3 »-o © — =5 33d 5-2P 33 © "— ^ "" « 2 "© >-.o _ " 3 03 !_ © jj © ■*• 3 ,-. — . CC t>- 550 MANUFACTURE OF SOAP AND CANDLES. alcoholic and ethereal solution 1 gramme of very finely pow- dered AgN0 3 is added, and the contents of the cylinder are shaken thoroughly for ten or fifteen minutes. After the precipi- tate has settled, 50 cubic centimetres are measured off, and if necessary filtered into a second graduated cylinder. A little more AgN0 3 is added to see if the precipitation is complete, and then 20 cubic centimetres of dilute hydrochloric acid (1 : 2) to decompose the silver resinate. An aliquot part of the ethereal solution in the cylinder is evaporated in a tared dish, and weighed as resin, deducting a small correction (for 10 cubic centimetres deduct 0.00235 gramme) for oleic acid. The amount of resin sub- tracted from the combined weight of fatty acids and resins, as found before, gives the fatty acids. (7) Sodium carbonate, (8) Sodium chloride, (9) Sodium sulphate, (10) Sodium silicate, (11) Insoluble residue: The filter in the funnel connected with the return-cooler, after treatment with alcohol, contains the mineral constituents of the soap. The contents of the filter are washed with cold water till the washings amount to 60 cubic centimetres. The filter is then dried and weighed. The weight gives the in- soluble residue and starch. The starch is converted into glucose with dilute acid, and titrated with Fehling's solution. The weight of starch found, subtracted from the total weight of in- soluble residue and starch, gives the insoluble mineral constitu- ents. The aqueous solution of 60 cubic centimetres, just men- tioned, is divided into four equal parts, in one of which is de- termined the carbonate of soda by titration, and in the other parts the chloride, the sulphate, and the silicate respectively by any convenient method. PART II. THE MANUFACTURE OF CANDLES. CHAPTER I. INTRODUCTION. Historical notice. — Of all the means of artificial illumination candles are perhaps the most convenient, and the materials of which they can be made are generally easily obtained and many of them cheap in cost. The manufacture and introduction of candles amongst the domestic conveniences of life, were in a manner no less productive of refinement in the taste and habits of communities than were those of soap and glass. It is difficult to trace from history the first introduction of the candle. Illum- ination by its means was not known to the ancient Egyptians and Jews. Though in Holy Writ many references are made to candles and candlesticks, upon further consulting the same sacred record it will be observed that these terms were used either in a metaphorical sense, or otherwise the translators have been at fault in rendering the meaning of a word in the Oriental tongue by one which does not express the same in modern languages. That the candlesticks spoken of were intended to support lamps, not candles, is plain from the instructions Moses received from the Almighty for making the golden candlestick. " And thou shalt make the seven lamps thereof, and they shall light the lamps thereof y that they may give light over against it."* Further testimony show- ing that olive-oil was employed for those lamps may be found in the Book of Leviticus, from which, as well as from the fore- going, it is plain that candles were not in use among the ancient * Exodus XXV., 37, 38. 552 MANUFACTURE OF SOAP AND CANDLES. Jews. The Romans were equally ignorant of the candle, and although Pliny and other writers mention it, yet the only infor- mation to be gathered from them is that their candles consisted of strings of flax, saturated and covered over with pitch or wax, probably not unlike those formerly used by laborers for working at night. Pliny also records the use of the pith of reeds satu- rated with fat as a night-light, which was placed alongside a corpse as long as it remained in the house. He also mentions strips of papyrus and reeds, steeped in pitch and then coated with wax. According to some statements, the manufacture of candles is contemporary with the persecutions of the early Chris- tians by the Roman Emperors, particularly when the former took refuge in the catacombs from the rage of their oppressors. This assertion is rendered more probable from the fact that it is cus- tomary since that period to burn candles in all church ceremonies of the Roman church, and Apuleius, near the end of the second century, makes a distinction between wax and tallow-candles (cerei and sebacei). Beckmann, in his " History of Inventions," relates that the Emperor Constantine, who ruled about the beginning of the fourth century, caused the whole city of Constantinople to be illuminated with lamps and wax candles one Christmas eve, and that the night had been lighter than the brightest day. In the middle ages the use of wax candles and wax torches for church and household purposes was well known, and Fosbrook mentions that the wicks were made of twisted tow and the candles were cast in moulds and varied from a very small size to fifty pounds in weight. At first they were, very likely, only used in the houses of the rich, as wax was scarce and commanded a high price, which is best proved by the fact that Philip the Bold, Duke of Burgundy, in 1361, offered to present St. Anthony, of Vienna, with his weight in wax for the cure of his sick son. Before the invention of clocks the consumption of a wax candle of determined length and thickness served frequently for the approximate determination of time. On account of the rites and ceremonies of the Catholic Church, the consumption of wax candles became enormous, but decreased somewhat by the spread of Protestantism, to be, however, abun- CANDLES — INTRODUCTION. 553 dantly made up by the luxury of courts, especially in the eigh- teenth century. Before the Reformation 35,730 pounds of wax candles were, for instance, annually consumed in the Cathedral at Wittenberg, and at a single court entertainment in Dresden, 1770, 14,000 wax candles (about 675 pounds) were burned. An idea of the enormous consumption of wax candles at the Berlin Court during the reign of Frederick William II. may be had from the fact that an annual defalcation of about $4500 in their purchase remained undiscovered for many years. Tallow candles were already known in the twelfth century, but came into general use as a cheaper illuminating agent only in the fifteenth century. Candles remained, however, too scarce and high-priced for use among the masses, and they do not seem to have been in general use until the middle of the last centurv, nor was there any important improvement in the art from the first crude methods of dipping, except that they were about that period moulded in metal moulds. Indeed, up to our own century very little improvement can be traced, nor did candles receive their due importance or approach their present perfection until the discovery of the elements of the fatty bodies and their decom- position into the fatty acids, stearic and palmitic. When in 1830 paraffin was discovered by Reichenbach, candles were still further improved by the addition of this valuable sub- stance to stearic acid to prevent crystallization, or the stearic acid was combined with the paraffin to improve them and prevent their softening and bending in a warm atmosphere. Candles of wax or tallow were first made by dipping, though the former were sometimes made by drawing and rolling, a mode still in vogue. The moulding of candles is of quite a recent date, for though they were moulded after a fashion over a hundred years ago, they were not made systematically until 1820. At the present time, owing to the many improvements in the materials and in the appliances for moulding, the manufacture of candles may be said to have reached perfection. Evolution of light by the candle. — The functions of the candle as an illuminating material are by no means as simple as they would appear at the first glance. Frederick Knapp says : " The candle may be considered as a real microcosm of illumination, in 554 MANUFACTURE OF SOAP AND CANDLES. which all the individual functions regulate each other. The curious manner in which the separate functions mingle in a candle and pass one into the other, in carrying out the main object, as well as the force of long habit, render the very same apparatus (as far as the principle is concerned), performing the same opera- tions, less remarkable to the casual observer than gas illumina- tion, which, being carried out on so extensive a scale, and at a vast expense, excites more general astonishment." A very important part of the candle is the wick, it being the intermediary link between the fatty substance and the flame. It consists of a bundle of fibres and dips with the lower end into the fluid illuminating substance and with the upper into the flame. The original, and not yet obsolete material employed for wicks, was the common soft rush Juncus conglomeratus, to be found in moist pastures, and by the sides of streams and ditches. Fine cotton-yarn is, however, the principal material used at the present time. Turkish -cotton rovings are said to be the best, but of the cotton employed for this purpose there is certainly a great deal more grown in the United States than in Asia Minor. Several processes must actually be distinguished in a burning candle, each of which must keep within correct bounds, in order to produce, by their organic mingling into each other, a steady, bright, and faultless flame. These processes may be divided into two physical and two chemical ones :- — 1. The melting of the illuminating material. 2. The absorption of the melted material by the wick. 3. The decomposition of the melted material into gaseous and vaporous products. 4. The combustion under the most favorable circumstances for the development of light. The burning candle must, therefore, accomplish by itself that with which a lamp is provided with from the start — the fluid illuminating substance, which in a lamp can be regulated by the manner of construction, the supply of air, and the conveyance of oil to the wick. In a burning candle the fat below the flame is melted into the form of a hollow cup by the heat constantly radiating in all directions. A reservoir is thus formed in which that which is CANDLES — INTRODUCTION. 555 melted by the heat uninterruptedly collects, and from whenee it is at the same time conveyed to the flame for its nourishment. If, now, on the one hand, the illuminating material melts at a greater ratio than corresponds to its capability of decomposing and the ability of absorption of the wick, the candle will gutter, and if, on the other, all the gasified illuminating material is not consumed, the flame will soot and languish by the deposited soot obstructing the capillary channels of the wick. Such deposit of carbon frequently occurs, as is well known, especially in the flame of a tallow candle. One of the principal conditions for the regular process of illu- mination is that the wick should stand in the centre of the candle, and, besides capillarity, must possess another property quite as essential. The flame is always produced at that part of the free wick which is in the middle between its point of most active capillary action and the point where the flow of melted fat is excessive, therefore always at the same distance from the bottom of the above-mentioned hollow cup. The wick, there- fore, if the candle is to regulate itself, must shorten as the candle diminishes, i. e. y it must be prepared from a substance which is combustible in the heat of the flame. The wick-yarn of com- merce consists, as previously stated, of cotton rovings. The wick of tallow-candles is much thicker and more abundantly saturated with fat than that of stearin candle, because tallow melts at from 98.5° to 104° F., while wax and stearic acid, as found in commerce, melt at somewhat above 140° F. A flame developing a determined degree of heat will, therefore, melt in a given time and, at a determined distance from the candle, more tallow than stearic acid. This is, however, not the case with our ordinary candles, a tallow-candle not being consumed quicker than a wax or stearin-candle of the same thickness. From the position of the wick in the axis of the candle, the requisite quantity of air, being used up by the flame itself, does not reach the wick, and completely consume it. The fibres of cotton are, therefore, charred, and they remain so until some part projects beyond the flame, and, coming into contact with the air, is consumed. If this happens, as it generally does, too late, then soot collects, in consequence of the interruption of the flame, as a 556 MANUFACTURE OF SOAP AND CANDLES. spongy stuff on top, darkens the flame, and falls eventually, if not removed with the snuffers, into the above-mentioned hollow cup, where it causes further interruption of the process. The thin, and especially the plaited, wicks of wax and stearin-candles have the property of bending as soon as a part projects beyond the flame, and being thus constantly reduced to ashes, snuffing is not required. By this the symmetry of the flame is, of course, partially destroyed, as it follows the inclination of the wick, and consequently melts too much fat on the one side, which gutters over the melted edge of the cup. Generally speaking, no candle exhibits an equilibrium of the above-mentioned points, whatever be the material of which it is composed — tallow-candles generally much less so than others — for, independent of the fusibility of the material, it is influenced by the relation which the mass of fat, i. e., the thickness of the candle, bears to the size of the wick, a relation which has been established approximately by long experience. The usual dimen- sions of a candle are, therefore, not fixed arbitrarily or by chance, but are absolutely necessary to a well-regulated process of combustion. The principal task of the illuminating material is to furnish gases for the production of a brightly burning flame. Every fluid or solid body which vaporizes or gasifies under decomposi- tion at a temperature lower than that required for combustion can, of course, only burn as gas, and the phenomenon of light thereby observed is called " the flame." It acquires its well- known form by the pressure of the air surrounding it, which, as a gaseous body rendered lighter by the heat, is displaced, and caused to ascend. The wick directly contributes nothing to the development of light, and may consist of capillary mineral sub- stances (asbestos), fine glass tubes, etc., though the latter, on account of conducting more heat, would melt the fat around the wick too much. The flame, at first small and of little illuminating power, in- creases to within a certain limit with the progressive decomposi- tion of the fat. Moreover, the decomposition of the melted fat does not take place suddenly, but gradually, i. e., in the degree as, in ascending in the wick, it reaches the hotter points of the flame. CANDLES — -INTRODUCTION. 557 Fig. TOO. It is first decomposed into its immediate constituents — stearic, palmitic, and oleic acids, and glycerin — and these into products of decomposition of a higher order — margaron, acrolein — and the latter finally into permanent gaseous hydrocarbons, i. e., such as contain no more condensable bodies, marsh-gas, etc., as well as varying quantities of hydrogen, carbonic acid, etc., and vaporous, incompletely gasified substances. The first and most important elucidation in regard to the nature of the flame and of illuminating itself, we owe to the re- searches of Sir Humphrey Davy. In modern times many chem- ists have devoted much time to the study of the flame, the labors of Hilgard, Landolt, Deville, Knapp, etc., having much con- tributed to our knowledge. The evolution of the burning gases, as well as their combus- tion, and the shape of the flame can be nicely observed in a lighted candle, K, Fig. 100. The melted illuminating material b is absorbed by the wick d, and converted into gas, which, flowing out from the point of the wick, surrounds the latter in the shape of a cone. For distinct parts can be recognized in this cone of gas the lower part (1), which burns with a pale-blue flame ; the veil (2) of very weak illuminating power. It consists of burning carburetted hydrogen, and surrounds the actual luminous cone of flame, (3) which also consists of burning carburetted hydrogen, in which are diffused glowing hydrocarbons. The dark central nucleus (4) consists of gases not in a state of combustion. The air surrounding the current of gas arising from the candle can only penetrate to a certain depth, as seen by the limits of the luminous cone of flame. The conical shape of the flame is explained by the interior masses of gas not in a state of combustion pushing upwards in columns, becoming gradually thinner, similar to the parts of a spy-glass, and reach- 558 MANUFACTURE OF SOAP AND CANDLES. ing combustion by degrees. That the temperature of the flame is highest on the edges of the luminous cone, and decreases towards the nucleus, is readily proved by holding a match cross- wise in the flame, when the portion immediately on the edge of the cone will be strongly charred, while the intermediate portions of the wood remain white. The consumption of oxygen caused by the illuminating mate- rials under medium atmospheric pressure is, according to the materials used, as follows :— 1 kilogr. of tallow consumes tb e oxygen from 16.35 cubic metres of air. 1 " wax a < i a 10.41 a a 1 " rape-oil a a a 12.21 it n 1 " illuminating gas " i 1 tt 13.62 a a The amount of carbonic acid generated does not exceed that produced by the process of breathing and is on an average about 0.4 cubic metre per hour. If by blowing out the flame of a tallow candle, the temperature is so far reduced that the fat contained in the point of the wick is decomposed but a combustion of the products of decomposition cannot take place, the product of decomposition of glycerin, known as acrolein, is developed. The test of the illuminating value of a fat, oil, or gas serving for illumination (photometry) can only be a comparative one, i. e. : , it can only be determined how much more or less effect is pro- duced by one than by the other. The quality of an illuminating agent depends (1) on the intensity of the light it produces as compared with another material, and (2) on the consumption of material in a determined time to produce the same intensity of light. The performance of an illuminating material increases therefore with the decrease in the consumption of material, and conse- quently is equal to the intensity of the light divided by the consumption of material. The quantity of solid or fluid illumi- nating material consumed is ascertained by weighing before the experiment and reweighing after burning for a certain measured duration. With illuminating gas the volume consumed in a certain time is measured. In photometric experiments it must be carefully observed that CANDLES — INTRODUCTION. 559 the intensity of the light of a flame does not alone depend on the material and the consumption, but also on the apparatus in which it is burnt. The various shapes of burners for gas are, for instance, not at all alike in their performances ; it is further not indifferent in what kind of lamp the oil is burned, and it depends even on the thickness of the wick and the diameter of the candle, whether the performance of a candle material is more or less good. To test, therefore, the value of a material in every respect, the experiments should be executed with various forms of appa- ratus and material. The intensity of the light is determined by instruments known as photometers. As far as used for technical purposes they are based upon the physical law, that the intensity of the illumination of a plane decreases in the ratio in which the square of the distance between it and the source of light increases. Two unequal intensities of light can only be made comparable by changing the distances of a screen catching the light until the effects of both are alike and then measuring the distances. A photometer much in use at the present time is based upon a principle first applied by Bunsen. Upon one side of a long horizontal rod stands the normal light (a paraffin candle, six of which =1.1 pound) which is used as a unit and the flame of which, for every experiment, is brought to a determined length by trimming the wick, etc. Upon the other side is the candle or other source of light to be examined, and between both is a mov- able screen of thin paper rendered semi-transparent by being saturated with a solution of spermaceti in oil of turpentine, with the exception of a central spot which is allowed to remain opaque. In using the apparatus (in a dark room) the standard light is placed behind the spot and the light to be examined in front. When the two surfaces are equally illuminated, the opaque spot disappears and the whole surface of the disk is perfectly homo- geneous in appearance. To save the calculation of the intensity of the light of the illuminating material to be examined from the distance of the screen, the intensity of light corresponding to every position of the screen is marked upon the rod. The simplest and most readily constructed photometer is that 560 MANUFACTURE OF SOAP AND CANDLES. known as Rumford's. It is based upon the above-quoted physical law. It consists merely of a black cylindrical rod mounted vertically upon a stand and a white screen upon which to receive the shadow of the rod. The lights to be compared are placed in such a position that the respective shadows cast by the rod lie as closely as possible together and are of equal depth. According to the above-quoted law, the intensities of the lights are then as the squares of their distances from the screen. For example, supj)Ose light A at 42 inches and lamp B at 60 inches from the screen gave equally deep shadows ; then, since 42 x 42 = 1764 and 60 X 60 « 3600, lamp A is to lamp B as 1764 to 3600, or nearly as 1 to 2, or, in other words, lamp B gives twice as much light as lamp A. According to experiments by Dr. Frankland (1863) the follow- ing quantities of illuminating materials give the same amount of light. Tallow candles . . . 35.86 pounds Stearin candles . . . . 27.50 " Wax candles . . 26.29 Spermaceti candles ' . . 21.81 Paraffin candles . 18.52 Paraffin-oil 7.97 pints. Petroleum, according to quality 10.03 to 10.2 MATERIALS FOR CANDLES. 561 CHAPTER II. MATERIALS FOR CANDLES. In addition to tallow, palm-oil, Chinese tallow, and the various fats and oils described in Chapter V., and of stearic acid, the manufacture of which by the various processes is described and illustrated in Chapter II., there are several other classes of hydrocarbons which are largely used by the candlemaker. Per- haps the material next in importance to stearic acid is Paraffin, sl product of the distillation of several organic bodies under high temperatures. The discovery of this body fairly be- longs to Karl Reichenbach, who gave to the strange compound its present name, from parum and qffinis, because it appeared to him to be wholly destitute of chemical affinities. His discovery and its peculiar behavior in this respect were published in the year 1830. The following year its presence in the petroleum of Rangoon was noticed by Christison of Edinburgh. He called it petroline, but hearing subsequently of Reichenbach's discovery, he was satisfied of the identity of the two substances and with- drew the name given by himself. In 1833, 1834, and 1835, we have records of the separate discoveries by the three chemists Laurent, Gregory, and Viobel, the former showing that the oils distilled from shale contained paraffin. The credit of founding the commercial industry based upon the manufacture of paraffin and its allied products belongs to no one person more properly than to Seligue, of France, and to his genius and indefatigable industry belong the many improvements made in the manufac- ture of oil from bituminous shale. From Prof. F. H. Storer's remarks on the discoveries of Seligue in connection with the paraffin industry we make the following extract, which suc- cinctly details the various processes secured by him : — "On the 27th of March, 1839, Seligue specifies certain addi- 36 562 MANUFACTURE OF SOAP AND CANDLES. tions and improvements to a former patent. In alluding to the use of his oils in the treatment of cutaneous diseases, he speaks of the three large establishments for the distillation of bitumi- nous shale, which he has erected in the department of Saone et Loire, and mentions the fact that the crude oil is furnished at the rate of ten centimes per pound. The clearest of all of Seligue's specifications, however, is that of the patent granted to him March 9, 1845, for the bituminous shales and sandstones. After describing the various forms and apparatus used in distilling, into one of which superheated steam was introduced, he enume- rates the products of distillation as follows : I. A white, almost odorless, very limpid mineral-oil, somewhat soluble in alcohol, which may be used as a solvent or for the purpose of illumina- tion in suitable lamps. II. A sparingly soluble mineral-oil of 0.84 to 0.87 specific gravity, of a light-lemon color, perfectly limpid, almost odorless, never becoming rancid, and susceptible of being burned in ordinary lamps having an elevated reservoir, with double current of air, a slight modification of the chimney and burner being alone necessary. This oil can be mixed with the animal and vegetable oils. Oils thus prepared do not readily become rancid, nor do they congeal easily when subjected to cold. III. A fat mineral-oil, liquid at the same temperature as olive- oil. This oil contains a little paraffin and is peculiarly adapted for lubricating machinery, having an advantage over olive and other vegetable oils, or neat's-foot oil, in that it preserves its nnc- tuousness when in contact with metals and does not dry up. IV. From the oils I., II., and III., I extract a red coloring matter, which can be used in various arts. V. White crystalline par- affin, which needs but little treatment in order to be fit for making candles. This substance does not occur in very large proportion in the crude oil, and the proportion varies according to the different mineral substances upon which I operate. There is but little of it in petroleum and in the oil obtained from bituminous limestone. I often leave a great part of the paraffin in the fat oil and in the grease in order that these may be of superior quality. VI. Grease. This grease is superior to that of animals for lubricating machinery and for many other pur- poses, since it does not become rancid and remains unctuous when MATERIALS FOR CANDLES. 563 in contact with metals. VII. Perfectly black pitch, very dry- ing, suitable for preserving metals, wood, etc. VIII. An alka- line soap obtained by treating the oils with alkalies. IX. Sufc phate of ammonia. X. Manure, prepared by mixing the ammoniacal liquor, or the blood of animals, with crushed fixed residue (coke) of the shale. XI. Sulphate of alumina from the residue of the shales." To Dr. James Young belongs the honor of creating the par- affin industry in Scotland. In 1850 he took out his celebrated patent for the distillation of coal minerals at a temperature not exceeding 600° F. According to G. T. Beilby the oil-shale belt extends right across Scotland, from Ayrshire and Renfrewshire on the west to Midlothian and Fifeshire on the east. The minerals worked in the west are among the upper series corresponding closely to cannels or coals ; those worked at the centre of the belt between Shotts and West Calder are intermediate, while those in Mid- lothian and Fife are lowest. It is curious that the western min- erals yield the largest quantity of oil per ton, but of the poorest quality, while the eastern minerals give the smallest yield per ton, but the oil is of the finest quality ; and in this respect the central district in the belt is intermediate between east and west, the quantity and quality of the oil being an average. Oil shales are mined and brought to the surface in much the same way as coal. The crude oil obtained from the shales is subjected to fractional distillation, and the last fraction is very heavy, containing 30 per cent, of paraffin. The hard scale separates from the oil by crys- tallization in ordinary weather, and the residual oil is then arti- ficially cooled and yields a further quantity of soft scale. The crude, solid product thus formed is known as " paraffin scales," and is of a somewhat variable composition. The impurities amount, on an average, ,to 20 per cent, of the weight, and consist of blue oil, greasy hydrocarbons of low fusing point, solid refuse, and water. For purification the paraffin scales are melted in a large pan by the introduction of steam through a perforated iron coil. The mechanical impurities and water having subsided, the supernatant liquid is brought into another tank, where it is 564 MANUFACTURE OF SOAP AND CANDLES. mixed with a certain quantity of naphtha, and the mixture is allowed to settle for some time to remove adhering water and suspended matter. The clear liquid is run down into cooling tins, which are arranged in racks or frames. In these it is allowed to remain about 24 hours, and cools into firm cakes. These cakes are turned out, wrapped in canvas sheets, and pressed between iron plates in a hydraulic press. The naphtha, carrying with it oil and coloring matter, is squeezed out, leaving a dry cake of paraffin. This operation of solution in naphtha, cooling, and pressing is repeated two, three, or four times until the de- sired degree of purity is reached. The cakes are then melted up and steamed in the still until all traces of naphtha are removed. The steamed paraffin is carefully separated from water and run down into the so-called " black tank/' where it is mixed with from 5 to 8 per cent, of freshly burned animal charcoal, and after vigorous stirring for half an hour allowed to settle. It is then run through filters to remove the fine particles of charcoal that refuse to subside, and cooled in pans or tins, when it will be ready for candle- making. Several materials have been substituted for charcoal in the above process, such as the addition of about 12 per cent, of fullers 7 earth, at a temperature of 230° F. The mixture is well agitated, then left to settle, and the clear paraffin is run off. The fullers' earth may be cleansed from paraffin by washing or agitation, and used again. By another process, silicates of magnesia and of other bases may be employed for the same purpose. Moreover, a very ingenious process has been patented in England by Mr. Sterry, for removing the oil from paraffin without pressing. It consists in simply washing or rather kneading the paraffin with a solution of soap at a temperature of 9° F. below the melting point of the paraffin. The product is pure white, but opaque, hence its use is limited. In this country paraffin is wholly a by-product in the manu- facture of lubricating oils, or in the treatment of the heavy oils proceeding from the distillation of petroleum towards the last of the process. For the following description of the manufacture of paraffin in MATERIALS FOR CANDLES. 565 this country we are indebted to Benjamin J. Crew's Practical Treatise on Petroleum. In treating the subject from the standpoint of the American refiner, the preparation of lubricating oils and -the manufacture of paraffin- wax run so closely together that at some points at least they touch and must be treated as though they belonged to one subject. The manufacture of either or both begins when the residuum is placed in the still. The first products of this distilla- tion down to about 32° B. (which when they are received into one tank constitute an oil of 38° B.) are returned as crude oil. After the separation of this first part, the products of the still are pumped into the " paraffin agitator," where they are first treated with acid, and after drawing off the " acid sludge," washed with alkali and water. Care should be taken throughout that the proper temperature be preserved so that the paraffin shall be maintained in perfect solution. The oil is then allowed to flow by gravity or it is pumped into tanks, provided with a steam coil, in order that its contents may be preserved in a perfectly limpid state to permit of the settling of the water. This being drawn off, the contents are removed to another apartment, the tempera- ture of which has been artificially lowered by a freezing machine, where it is subjected to the chilling process. In the winter the ordinary temperature is sufficient to crystallize the paraffin. If the process is to be carried on during the warm weather, the contents of the tank are barrelled and the tempera- ture of such a room may be reduced by a good apparatus to 10° or 15° F., even in very hot weather. An exposure of the paraffin- oil for forty-eight hours chills the whole mass to a complete solid. From the barrels the contents are shovelled out into small cotton bags of very strong material and subjected to powerful pressure by means of a hydraulic press. The cakes when removed from the bags are somewhat variegated in color, some portions being of a light lemon, others presenting quite a greenish hue. The contents of the bags are thrown into a steam tank, where the cakes are melted by live steam, one per cent, of soda lye is added, and the whole thoroughly steamed, the condensed water withdrawn, and when sufficiently cool to admit of the process, about 25 per cent, of benzene is added, and the whole vigorously stirred until 566 MANUFACTURE OF SOAP AND CANDLES. a homogeneous mixture is obtained. The contents of this tank are ladled out into shallow tin-pans, holding about 5 to 10 gallons each, which are allowed to remain in the cold room for three to four days. This product is again subjected to pressure in clean bags. The paraffin thus obtained is in large crystals with a slight tinge remaining, and having a much higher melting point (about 130° F.) than the crude article first described. Chemically, paraffin is a mixture of hydrocarbons of the series CnH 2 n + 2. It is white and odorless, soluble in alcohol, and can be distilled without decomposition. The melting and congealing points of the various kinds of paraffin vary very much, as well as the specific gravity. Sauerlandt gives, for instance, the congeal- ing point of paraffin as from 100.5° to 179.5° F., and its specific gravity as from 0.869 to 0.943. The higher the melting point, the greater the specific gravity. Pure paraffin is sometimes used alone for candle-making, but is generally mixed with proportions of hard stearic acid varying from 5 to 10 per cent. Ozokerite or mineral-wax. — Ozokerite or mineral wax occurs generally in fissures and cavities in the neighborhood of coal fields or deposits of rock-salt, or under sandstone pervaded with bitumen. Although it is widely distributed over the world, a solid paraffin with a high melting point is only obtained from the deposit in Gallicia, where miners' candles have long been made from it. The color of the mineral varies from brown to greenish and yellow tints ; its fracture is resinous. The structure and melting point of ozokerite depend, according to Sauerlandt, on its principal constituents — paraffin and " waxy resin' 7 — because, with the distillation of ozokerite conducted with superheated steam and the avoidance of decomposition, he dis- tinguishes the following constituents :— 1. Liquid hydrocarbons with a low boiling point. 2. Paraffins, chiefly with a boiling point of from 140° to 158° F. 3. Resinous bodies, called " waxy resins." 4. Bituminous resins. 5. Coke. MATERIALS FOR CANDLES. 567 Paraffin and waxy resins are solid bodies, the latter having a higher melting point than the former. The paraffin mass obtained by distillation has a melting point of from 113° to 122° F. After complete crystallization, the paraffin scales are separated from the oil by centrifugals and fil- tering presses. The scales thus obtained still contain 20 to 25 per cent, of oil. To separate this, the paraffin is packed in press-cloths, and subjected to pressure in a hydraulic press with heated plates. Reichenbach's method of purifying the crude paraffin with concentrated sulphuric acid has been almost entirely abandoned, as also the distillation over lime or chloride of lime. The crude paraffin, after melting, is at present treated in a similar manner as petroleum-paraffin, with about 15 to 25 per cent, of benzene of not more than 0.785 specific gravity, and then subjected to pressure in a hydraulic press. The operation is repeated seve- ral times, according to the desired degree of fineness, and the benzene adhering to the paraffin after pressing expelled by treating with steam for ten to twelve hours. The paraffin is then fined by digesting with animal charcoal or similarly acting sub- stances, and finally filtered through blotting paper. Ozokerite paraffin thus obtained shows a melting point of about 144° F. The process of purification by acidification with strong sul- phuric acid gives eeresin, a substance much resembling beeswax in consistency and fracture. By this method, the whole of the mineral is converted into a homogeneous vellow substance with- out much loss except that of filtration and a certain amount of charred products. The process of preparing eeresin by means of sulphuric acid is, however, defective, and now almost entirely replaced by that of extraction, which yields a paler product from the start, which is easier to purify. The specific gravity of eeresin is much lower than that of bees- wax, it varying between 0.915 and 0.925 (beeswax 0.963 to 0.969) at 59° F. The melting point varies between 154° and 176° F., the congealing point being on an average 37° to 39° F. lower, while the melting and congealing temperatures of beeswax are the same. 568 MANUFACTURE OF SOAP AND CANDLES. Ceresin is extensively used as a substitute for wax. As a ma- terial for candles, it can, however, not be utilized by itself, as the candles do not burn with a clear flame like those from stearin, paraffin, or beeswax, but it can be advantageously used as an ad- dition to those materials. The use of ozokerite paraffin for the manufacture of candles has many advantages. It has a very high melting point, and does not bend or soften in a warm atmosphere. It has great illu- minating power, burns with a dry " cup," and is not so liable to gutter as ordinary transparent candles. It is entirely free from smell, not unctuous to the touch, and has the appearance of the finest bleached beeswax. Waxes. 1. Waxes of animal origin.— -The most important animal wax for the manufacture of candles is Beeswax from Apis meUifica, Linn., or the bee, which yields most of the wax found in commerce. The wax is secreted upon the ventral scales of the bee, and used by the insect for the con- struction of the comb, the cells of which are hexagonal with angular bottoms. The comb, from which the honey is allowed to drip, is first subjected to pressure, and is then melted in boiling water, to free it from adhering honey and other impurities, and then poured into flat moulds, previously moistened, and left to cool. In a pure state, beeswax is perfectly white, but becomes colored by the contact with honey and pollen, the color of crude w T ax being more or less yellow, and sometimes even reddish or greenish, according to the materials used by the bees. For purification, the process of melting the wax in hot water is repeated until it is freed from all honey, and shows no longer a gray color. The destruction of the coloring matter by chemical means is not advisable, as chlorine and other bleaching substances exert a decomposing effect upon the wax, making it brittle and crumbling, which has to be remedied by an addition of tallow. The use of chlorine is further objectionable on account of the MATERIALS FOR CANDLES. 569 formation of products which, later on, by combustion, develop hydrochloric acid. The best method of bleaching is to melt the yellow wax in a large vat by means of steam. It is then run off, while in a melted state, into a trough, called a cradle, which is perforated on the bottom with holes, and placed over a large water-tank, at one end of which is a revolving cylinder almost immersed in water. By this means the wax is solidified, converted into a kind of ribbon, and conveyed on the surface of the water to the other end of the tank. These ribbons of wax are lifted out, and carried in baskets to the bleaching ground, where they are ex- posed to the air for one or two weeks, according to the weather, being turned every day, and watered from time to time. By another process, the wax, purified by steam, is obtained in threads or grains by allowing it to drop in a thin stream, or drops, into ice-cold water from a revolving tinned-copper boiler provided with one or more cocks. By this granulating and thread-drawing process, a greater surface is exposed, and the bleaching process shortened at least one-third. After exposure upon the bleaching grounds the wax is re- melted in hot water, strained, and poured into moulds to cool. The loss in weight caused by bleaching is from 2 to 10 per cent. To assist the natural or sun-bleaching process, which is based upon the formation of ozone and the action of the latter upon the coloring matter, by a further formation of ozone, the yellow wax is melted together at a moderate heat with rectified oil of turpentine in the proportion of 8 parts of wax to 1 to 1J parts of oil of turpentine. The mixture is melted, ribboned, and bleached in the same manner as wax. The bleaching process is much accelerated, being finished in five to six days, after which the odor of oil of turpentine has entirely disappeared. White wax is tasteless and inodorous, translucent on the edges, brittle, not unctuous to the touch, softens at 86° F. and in the hand by kneading, melts at 145.5° to 147° F., and has a specific gravity of 0.965 to 0.969. In buying wax great care should be exercised, as both the yellow and white varieties are frequently adulterated. The spe- 570 MANUFACTURE OF SOAP AND CANDLES. cific gravity and melting point are of special importance for the determination of quality. The most common adulterations are as follows : Admixture of water to increase the weight, which is readily recognized by the dull and rough fracture and by slowly heating to the melting point and cooling, whereby the water separates, the quantity being determined by weighing the cooled wax. Additions of pulverulent substances, such as yellow ochre, brick-meal, pea-flour, heavy-spar, clay, litharge, etc., are also detected by melting, whereby they separate. Stearin, resin, and vegetable waxes in- crease the specific gravity. Pure white wax floats in the centre of a fluid consisting of 2 parts of alcohol of 0.830 to 0.831 spe- cific gravity and 7 parts of distilled water, even if the fluid is brought to a specific gravity of 0.965 to 0.970 by the addition of distilled water. Pure yellow wax shows the same phenomenon in a fluid of 0.955 to 0.965 specific gravity, prepared as above from 1 part of alcohol and 3 parts of water. Adulterations with the above- mentioned substances would cause the wax to sink, while sophis- tication with paraffin, ceresin, ozokerite, etc., would make it float upon the surface. Generally speaking the principal adulterations are with yellow ceresin for yellow wax and white ceresin for white wax. Paraffin or ceresin, etc., is recognized by heating a sample of the suspected wax with fuming sulphuric acid in a porcelain dish. Pure wax is thereby entirely decomposed and converted into a black, jelly-like mass, from which the paraffin is separated in an unchanged form after cooling. Tallow. — By pouring spirit of sal ammoniac over scraped wax in a test-tube and heating, the fluid does not become turbid as is the case in the presence of tallow. Stearic acid is detected by dissolving a small quantity of wax in ten times the quantity of chloroform and adding lime-water. Pure wax remains dissolved, while in the presence of stearic acid a granular precipitate of stearate of lime (lime-soap) is formed. Resin. — Boil the wax with concentrated nitric acid ; in the presence of resin the fluid acquires a reddish color. By adding water to the fluid after cooling, and freeing it from wax, it becomes turbid, and the resin separates as a yellow, flaky precipitate, which dissolves with a reddish-brown color in MATERIALS FOR CANDLES. 571 caustic ammonia. Japan-wax. — Boil about equal parts of borax and wax with fifteen to twenty times the quantity of water; with pure yellow wax the milky, turbid mixture separates gradu- ally into a clear, yellowish fluid and with pure white wax into a clear fluid, with the wax in both cases floating on top. In the presence of Japan-wax the whole remains milky and, according to the quantity of adulteration, thickly fluid or jelly-like and rigid. There are a number of other methods of examining wax, but we have given the most simple and reliable ones and the quickest of execution. Chinese-wax is produced by Coccus pela, Westwood, or the white-wax insect of China, upon the branches of Fraxinus chi- nensis, Roxb., or the Chinese ash. The rearing of the insect in China is now an industry next to silk in importance. Chinese-wax, or insect-wax, differs entirely from Japan-wax, with Avhich it is frequently confounded, especially in literature. The branches of the trees having become incrustated with the wax secreted by the insects, are cut off in the month of August and boiled in water, whereby the wax collects upon the surface. Later on it is remelted and poured into deep pans, where it cools to a transparent and very crystalline mass. The wax is pure white or of a very slightly yellowish shade, tasteless and inodor- ous, lustrous and crystalline throughout. In appearance it re- sembles spermaceti, but is much harder and more brittle, can be almost pulverized, and is of a more fibrous structure. It has a specific gravity of 0.970 at 59° F., melts at 179.5° to 181.5° F., yields little to alcohol and ether, but is very readily soluble in benzene. It is difficult to saponify with boiling potash lye. It is not a mixture of various substances, but consists almost en- tirely of ceryl cerotate r V 27 -rr S3 > O. J ^27 H 55 J In China and Japan it forms an important article of commerce, being used in the manufacture of candles, which, it is claimed, possess ten times the illuminating power of ordinary candles. It is also used for coating candles manufactured from Chinese vege- table tallow. At the present time Chinese-wax is not of much commercial importance, as China consumes immense quantities, 572 MANUFACTURE OF SOAP AND CANDLES. but formerly it was largely brought to England in broad cakes perforated in the centre, and was much used in the manufacture of candles. Spermaceti. — The main source of this beautiful candle material is the cachelot or sperm whale (Physeter maerocephalus). It is found not only in the "head matter" but generally diffused throughout the blubber. After the death of the animal it forms a crystalline mass. The whale-oil is strained off, the remaining crystalline mass pressed and treated with weak caustic soda or caustic potash lye to saponify any adhering oil. It is then rinsed off in water and remelted in boiling water. Crude spermaceti, which is seldom found in commerce, forms finger-thick plates, which are yellowish, transparent, of a foliated structure, and a rancid, fishy odor. To convert it into the com- mercial article the plates are melted down and boiled for two or three hours with caustic lye of 14° B. in the proportion of 40 parts by measure of the former to 1J of the latter. The mixture is kept at a low, equable temperature, and allowed to remain at a gentle simmer, while the soap that has been formed rises to the surface and is skimmed off. The heat is then raised to about 250° F., and the mass is treated with small successive doses of water, the additional scum being carefully taken off as it rises, till the whole is clear. It is then drawn off to crystallize in flat tin-dishes. The cakes thus obtained are again reduced to powder, which is wrapped in linen bags and subjected to hot pressure in a very powerful hydraulic press. The cakes of spermaceti coming from the press contain still some oil which has to be extracted by saponification, which is effected by boiling with strong alkaline lye at 235° F., removing the scum as before. Further purifica- tion is then effected by introducing a small quantity of water at intervals, while the heat is lowered. The supernatant spermaceti, now perfectly colorless and transparent, is cast into blocks and crystallized. Pure spermaceti is talcky to the touch, tasteless, inodorous, and friable. It has a specific gravity of 0.943 at 59° F., melts at between 122° and 129° F., and, like wax, congeals immediately below the melting point. It is a mixture of various fats, but not of glycerides. By recryst alii zing it from spirit of O W O ) wine, cetyl palmitate ! A tt > O is formed. MATERIALS FOR CANDLES. 573 Spermaceti is not readily adulterated, as by every admixture it loses in a high degree its peculiar and very characteristic proper- ties. Adulterations are readily recognized by greater hardness, absence of nacreous lustre, and the small, foliated, crystalline struc- ture. For the manufacture of candles, spermaceti is generally mixed with about 3 per cent, of wax or paraffin, to counteract its crystalline structure. The candles burn with a bright, inodorous flame. The United States and England supply most of the spermaceti. 2. Waxes of vegetable origin. Japan wax. — This wax is ob- tained from the berries of several trees of the genus Rhus, indige- nous to China and Japan. The usual method to obtain the wax is as follows : The berries are ground and the floury mass obtained is boiled with water in large kettles and the wax skimmed off. To remove foreign admixtures, the cooled wax is several times remelted until entirely clear. By another process, the berries are first beaten with bamboo flails, then dried for fourteen days, slightly roasted, and ground. The floury mass is packed in small bags and exposed to the action of water vapor to melt the fat in the cells, which is then expressed by means of various kinds of presses. The extraction process has recently also come into use. The expressed wax being somewhat greener in color than that extracted with ether or bisulphide of carbon, it is boiled with dilute lye, whereby it becomes granular and more susceptible to the bleaching process, then washed with water and exposed to the sun. According to the degree of bleaching, the wax is known as prime and second. Japan-wax is now brought into commerce in square cakes weighing about 140 pounds each. It has a waxy appearance, is whiter and more brittle than beeswax, and breaks even or largely conchoidal. The surface of a fresh fracture is lustreless, while that of a cut one has a wax-like lustre. The wax can be kneaded between the fingers and chewed to a powder. Its odor and taste are somewhat resinous, tallowy, and rancid. By storing, it be- comes yellow to brownish, and, as it contains much water, is covered with a white, dust-like efflorescence. Japan-wax melts at 128° to 130° F. and congeals at 105° to 106° F. If remelted a short time after congealing, it melts at 574 MANUFACTURE OF SOAP AND CANDLES. 107.5° F., and reacquires the ordinary melting point of 128° F. only after long storing. The specific gravity of the crude wax is 1 to 1.006, and that of bleached wax 0.970 to 0.980 at 59° F. In Japan the wax is used as a substitute for tallow and bees- wax in the manufacture of candles, and for producing a lustre upon turned-wood articles. In Europe it is employed in the manufacture of wax-matches, and as an addition to bleached beeswax in the manufacture of candles, as it facilitates the removal of the latter from the moulds. The principal European market is London, which, in 1881, imported over 11,000 boxes, of about 132 pounds each. Fig-wax or getah-wax is obtained by evaporating the milky juice of Ficus cerifera, Blume, or the wax-fig tree, indigenous to West and Central Java, Sumatra, and Ceylon. It has a reddish- brown color, but becomes pure white by bleaching. It is very brittle, softens at 113° F., and melts at from 133° to 134.5° F. It is used like beeswax in the manufacture of candles. Cow-tree wax. — By making incisions into the trunk and limbs of the cow-tree (Galactodendron utile), indigenous to the moun- tains of South America, a milky juice resembling cow-milk in color and taste is obtained. It contains 30 to 35 per cent, of wax, which is separated by boiling. The wax is somewhat transparent, can be kneaded, melts at from 122° to 125.5° F., and can be partly saponified. In external appearance, it resembles beeswax more than any other vegetable wax, and yields very good candles, which burn with a bright flame. Myrica wax or myrtle tallow. — The fruits of Myrica cerifera, Linn., a fragrant shrub growing near Lake Erie, but chiefly along the Atlantic coast of North America, secrete a Avax which is de- posited in thin layers, and covers them with a snow-white crust, interspersed with small brown or black specks. The fruits are boiled in water, and the fatty mass collecting on the surface is skimmed off, and poured into shallow vessels. The yield is about 20 to 25 per cent., or 2 pounds of wax from 8 to 10 pounds of berries. The wax has a deep-green color, due to chlorophyll, which, by exposure to light and air for a long time, changes to gray-yellow, but only a few millimetres below the surface. It breaks with a MATERIALS FOR CANDLES. 575 shallow, conchoidal fracture. Its specific gravity is 1.000 to 1.005 at 59° F., and it melts at 113° to 115° F. It is used like beeswax, but, being less ductile and plastic, is generally mixed with it. In this country it is much liked for the manufacture of candles, as they diifuse an agreeable odor when extinguished. Carnauba-wax is secreted in thin films and scales on the leaves, stalks, and berries of a Brazilian palm, Coryphera&erifera, Linn. By shaking or pounding the leaves, etc., the wax peels off, and is melted over an open fire, or boiled with water, whereby the foreign substances settle on the bottom, and the wax collects on the top. The wax is dirty gray-yellowish to greenish, hard, brittle, and can be readily rubbed to a powder. It is tasteless, and, when fresh, smells like new-mown hay, but later on becomes inodorous. It is purified by remelting, and has then a greenish color which cannot be removed. Carnauba-wax acquires a reddish color by boiling with potash lye, is only partially and with difficulty saponified with alcoholic potash lye, and consists of myricyl alcohol, C 30 H 6iJ O, ceryl alcohol, C 27 H 56 0, and cerotic acid, C 27 H 54 2 , besides an undetermined quantity of resin. According to Allen and Thomson, 54.87 per cent, of it is non-saponifiable. Fresh, purified carnauba-wax melts at 185° to 187° F., old wax at 194° to 196° F., and congeals at 187° to 188.5° F., the cooled mass being somewhat crystalline. In melting, the wax diffuses a slight but not disagreeable odor, and by dry distilla- tion yields a paraffin-like product. Its specific gravity is 0.995 to 0.999 at 59° F. Valenta has determined the melting points of mixtures of car- nauba-wax with stearic acid, ceresin, and paraffin : — Mixtures of carnauba-wax with Addition of carnauba- wax with a molting point of 185° F. Per cent. stearic acid, with a melting point of 137° F. ceresin, with a melting point of 163° F. paraffin, with a melting point of H0° F. 5 10 15 20 25 157.50 164.75 166.15 167.0 168.2 174.30 177.0 179.0 180.5 181.4 165.00 174.3 178.0 179.0 179.0 576 MANUFACTURE OF SOAP AND CANDLES. Carnauba-wax is extensively used in the manufacture of can- dles and wax-varnish. Palm-wax is obtained from the common wax-palm {Ceroxylon andicola) and the Klopstock palm (Klopstockia cerifera). The trunk of both varieties secretes a resinous wax, which is scraped off, and converted into a compact mass by melting over an open fire, and purified by remelting. By another process the bark of the trees is boiled in water, whereby the wax, however, does not melt, but only softens, while the admixed impurities settle on the bottom. The wax thus obtained presents a yellow or yellowish-white mass, and is brought into commerce either in irregular lumps or balls. In hardness and brittleness it corresponds to carnauba- wax. It breaks with a conchoidal fracture. Both the crude and purified waxes have a specific gravity of 0.992 to 0.995 at 15° F., and, though they become soft by the heat of the hand, melt only at 215.5° to 221° F. Palm-wax is a mixture of wax and resin from which, by dis- solving in much alcohol, the wax is separated as a white, some- what crystalline jelly. By repeated washing and recrystallizing from a large quantity of boiling alcohol, it is entirely freed from resin. This pure wax is white-yellow, resembles beeswax, and melts at 161.5° F. to a but slightly colored liquid. It consists of ceryl cerotate and myricyl palmitate with resin. It is used in the manufacture of candles mixed with a little tallow to make it less brittle. The so-called palm-candles have almost a lemon- color, as palm-wax cannot be bleached. There are other waxes much used in their native countries, as Ocuba-wax from Ilyristica bicuhiba, Balanaphore-wax from Langsdorffia hypogcea, both growing in Brazil ; also Andaquies- wax, Cuba-wax, and others of uncertain origin. Sebacylic acid, should receive some notice as a material for the manufacture of candles, especially as it might serve to impart to candles with a low melting point a higher one. It is obtained by the dry distillation of oleic acid, and by treating castor-oil or ricinoleic acid with soda-lye. From 100 parts of ricinoleic acid over 81 parts of sebacylic acid are obtained, which melts at 260.5° F. Added to stearic acid, it prevents it from crystal- lizing, and 1 to 5 per cent, of it mixed with readily-melting fatty substances imparts to them the hardness of wax. MANUFACTURE OF CANDLES. 577 CHAPTER III. MANUFACTURE OF CANDLES. Wicks and their preparation. — The wicks for candles require close attention, for it is essential that they should be of the right size, of uniform thickness, and free from loose threads and knots, the latter causing the candles to gutter. At present the wicks generally consist of twisted or plaited cotton threads, though sometimes flax or hemp is used. The cotton-yarn most frequently employed is slightly twisted mule-yarn, Nos. 16 to 20 for tallow-candles, and Nos. 30 to 40 for stearin-candles, etc. The style of designating the degree of fineness of yarns is according to the English system, which is recognized in the United States, Germany, Belgium, Switzerland, etc. In order to understand the system, the following will suffice : Yarns, as is well known, come into commerce in hanks or skeins. The reel, upon which they are produced, has a circumference of 1J yards or 54 inches, English measure; 80 threads form a lay or wrap, 7 of which constitute a hank, the latter representing, therefore, a thread length of 54 x 560 English inches, or 2520 feet. The number of the yarn simply indicates the number of hanks which make an English pound weight, No. 16, for in- stance, being a yarn requiring 16 such hanks to make one pound, No. 40, 40 such hanks, and so on. In Austria and France other modes of numbering are in vogue, the numbers of an equal fine- ness, according to the Austrian system, being obtained by dividing the English number by 1.22, and that of the French mode of designation by dividing the English number by 1.18. The thickness of the wicks varies very much and depends on the material as well as on the diameter of the candles. For tallow-candles twisted wicks are generally used, the following proportions being the most customary ones : — 37 578 MANUFACTURE OF SOAP AND CANDLES. For an 8 candle to the pound 42 threads of No. 16 " 7 " " 45 " " 16 " 6 " " 50 " " 16 " 5 " " 55 " " 16 (( 4 ({ ii QQ (C << 26 For stearin, paraffin, spermaceti, and many composite candles, plaited wicks of a much liner grade yarn are used, the following being customary :• — ■ For an 8 candle to the pound 63 threads of No. 40 << q u a g7 ( ( (< 40 it 5 a ti 9^ u <« 40 it. 4 (< <( 208 " " 40 Before use the wicks, except those for tallow-candles, undergo a certain preparation by steeping them in the so-called "wick- mordants," by means of which they are rendered less combustible and the charred piece is prevented from swelling up. For this purpose compounds composed of solutions of ammoniacal salts (ammonium chloride, phosphate, etc.), of bismuth, of borates, or, boracic acid, are used. Bolley recommends a solution of ammo- nium chloride of 2° to 3° B. as being simple and cheap. Very Fig. 101. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ suitable also is a solution of 2 pounds of boracic acid in 1 J gallons of water. The wicks after thorough saturation with the solution are pressed and the excess of water removed by means of a centri- fugal. Payen recommends an addition of a small quantity of MANUFACTURE OF CANDLES. 579 sulphuric acid to the solution of boracic acid. Sodium borate cannot be used on account of the strong coloration the flame acquires therefrom. The twisting of the wicks is best effected by placing the single threads next to each other upon a table and turning so as to form a very elongated spiral. For the manipulations required many kinds of machines have been constructed, a very simple and effi- cacious one being shown in Fig. 101. The circumference of the wooden cylinder A, which is the principal portion of the apparatus, is equal to the length of a wick, and several cylinders with different circumferences for the various kinds of candles can be used. The iron axle of the cylinder rests in a very simple bearing in the parallel sides of a box B, which are as wide as the cylinder A. On the outside of the cylinder is a pulley, 0, connected with the driving-wheel D, Fisr. 102. r*JF by means of a cat-gut cord, similar to a spinning-wheel. The workman sets the driving-wheel and the pulley in motion by means of a crank with one hand, while with the other he allows the wick to run upon the cylinder A. (The apparatus can also 580 MANUFACTURE OF SOAP AND CANDLES. be so arranged as to be worked by a treadle.) When a few layers of wick have been thus wrapped around the cylinder, the latter is taken from the apparatus and replaced by another. The wick upon the cylinder is then cut with a sharp knife, thus separating it into equal lengths. A very handy wick-cutter for a large business, which is ex- tensively used in this country, is shown in Fig. 102. A is the body of the machine inclosing the pulleys and other appendages that regulate the movement of the carriage B, which is set in operation by the treadle G. The carriage B rests upon the body \ it is a kind of framework running on wheels, and containing a number of boxes placed shelfwise, and serving as a receptacle for balls of cotton-wick, the ends of which run through a notched reed below iJ, and come forward upon the twisting-board E, at the back of which a knife is fastened, that serves as the under blade of the movable clipper D. This, when drawn down vertically, severs the wick evenly. The twisting-box E O consists of two boards hinged, and moving on rollers. A turn of the crank near the end twists the wicks after they have been cut by the knife D, which having effected its purpose is drawn up again by a counter- poise F. At the front is a sliding-board so fixed as to regulate the length of the wicks. Fig. 103 represents a plan of a machine for cutting wicks, known as Sykes's patent, and Fig. 104 a sectional elevation of Fie. 103. Fie. 104. the same, a a is the frame, b a grooved roller over which the cords of twisted or plaited wicks are passed from the bobbins ccc, d is the clip or holder by which they are kept together. Fig. 105 MANUFACTURE OF CANDLES. 581 represents the clip on an enlarged scale in a side view. It con- sists of two side bars d d, which towards the centre are somewhat thinner. On each side a steel spring is affixed, which keeps the bars somewhat apart from each other, and a clamp e, through Fis. 105. which, when it is moved towards the centre, the bars can be brought near. If the wick ends are to be kept together between the two bars, the clamps e must be pushed towards the centre. By taking the wicks out or placing them in they are pressed towards the end. In the rear of this clip is a cutting apparatus consisting of a stationary blade, and a knife/ which has a handle moving on hinges, g is a small trough filled with liquid fat, which may be kept in a fluid state by steam, i is a band resting upon the table h« The following is the manner in which the apparatus is worked : The wicks being prepared in suitable bobbins are brought down through the roller b, and secured between d d of the clip. The bars d and d are made to lay firm hold of the wicks, by moving the clamps e e, which bring them together in consequence of the wedge-shaped form of the upper bar d. The wicks being thus secured, the clip is lifted up and drawn forward by the work- man, after which the free ends of the cotton that are left pro- jecting from it are immersed or brushed over with the hot fat contained in g 9 and then laid on the top side of the square broach or suspending rod i, and are made to adhere to it with sufficient firmness to sustain them during the process of dipping by a slight pressure. Next, the clip is slackened by moving the clamps e outwards ; they are then pushed forth over the cotton towards the bobbins, till the length to be cut for the candle is gained, when, by reversing the movements of the clamps ee, the wicks are again tightly grasped, and finally the clip is rested upon the table h, which is about one inch from the cutting apparatus. The movable blade / of the cutting apparatus is brought down, and the set of wicks of the proper length cut off, leaving as 582 MANUFACTURE OF SOAP AND CANDLES. much of the cotton adhering to the end next the suspending rod i as will support the next batch as before. The rod i, with the wick adhering to it, is placed in the dipping frame, and another rod again loaded with wicks as before, and so on till the frame is full. The bars of the clip may be hinged, so that, when open, they will allow the bundle of yarn or cotton to pass freely, but, when closed, they will take a firm hold of them, as shown in Fig. 105. A great many devices in plaiting and gimping of wicks have been patented and used, but it has narrowed down to the simple plaited wick for nearly all moulded candles, and the coarse, twisted one for dipped candles. Dipped candles. — No doubt the oldest method of manufac- turing candles is by dipping, i. e., by repeated immersing of the wicks in melted fat until the required thickness is obtained. Dipped candles are always made of tallow more or less purified. By mere melting and straining, the tallow is, however, not obtained entirely free from admixture of fine undissolved substances. For separating these substances, therefore, it must be clarified. This is done by remelting it upon water, either over an open fire or by steam. Generally, no more water than 5 per cent, is taken, and stirred well with the tallow, till the mixture forms an emulsion. The whole is then allowed to rest, without further heating, till the water has separated, when the tallow may be drawn off or ladled off. Sometimes, in order to conceal the yellowish tint, a very little blue color is added to the clear fat, consisting of indigo rubbed finely with some oil, of which a few drops are sufficient even for large quantities. The process of clarifying is occasion- ally repeated. To harden the tallow, add with constant stirring to 1000 parts of melted tallow, 7 parts of sugar of lead previously dissolved in water. After a few minutes, the heat is diminished, and 15 parts of powdered frankincense with 1 part of turpentine added, with constant stirring of the mixture. It is then left warm for several hours, or until the insoluble substances of the frankincense settle to the bottom. The hardening is produced by the sugar of lead, while the frankincense improves the odor of the tallow. For carrying on the manufacture of dipped candles on a small MANUFACTURE OF CANDLES. 583 scale, but very simple apparatus is required. The clarified and remelted tallow is poured into a tightly joined trough three feet long by two feet wide at the top, gradually diminishing to three or four inches at the bottom. A handle is fixed on each side for its easy removal, and when not in use, it is closed with a cover. The operator commences by stringing 16 to 18 wicks at equal in- tervals on a thin wooden rod, about 2J feet long, and sharpened at the ends. He then takes 10 or 12 such rods, and dips the wicks rapidly into the fluid tallow in a vertical direction. The tallow should be very liquid in order that the wicks be soaked as uniformly as possible, it being sometimes necessary to repeat the operation. On account of the high temperature of the tallow used, the wick, before cooling, has a chance to straighten out by its own weight. The workman then places the rods with the wicks in a certain order upon a frame to drain off. All the wicks being saturated with tallow, the second dipping is com- menced by taking two or three of the rods with wicks on which the tallow has first congealed, and immersing them in the tallow, which in the mean while has somewhat cooled off, and commenced to congeal on the edges of the trough. By this means, a thicker layer of tallow than the first adheres to the wicks. The dipping is then repeated until the candles have acquired the desired thickness, they being, of course, returned to the frame after each dipping to cool. The conical spire at the upper end is formed by immersing deeper at the last dip. Should the tallow become too cold during the operation, it is restored to the correct tempera- ture by the addition of hot tallow. Frequent stirring is also re- quired to prevent the stearin and palmitin from crystallizing out. In order to be able conveniently to regulate the temperature, it is best to use a jacketed copper kettle in place of the wooden trough. Dipped candles being seldom symmetrical, and generally somewhat thicker on the lower end, this defect is remedied by repeatedly dipping the lower end for a short time into hot tallow. Sometimes the candles are equalized by melting off, as shown in Fig. 106. The candles, strung on the rod B, are suspended in a trough without a bottom, C, so that the ends touch the copper or iron-pan D, which is somewhat inclined forward, and heated by 584 MANUFACTURE OF SOAP AND CANDLES. a coal-fire E. The tallow melted off runs into the collecting vessel F. Fig. 106. /)MhMM(M^mm Ay frame ; S, rod with candles ; (7, trough without bottom ; 2), pan ; U, coal- fire j F, collecting vessel for fat. By another method the candles are made symmetrical by pass- ing them through a drawing plate. This is made of hard wood, 12 inches long, 2 or 3 inches wide, and about f inch thick. It is perforated by a number of holes, graded from large to small, the last being the size required for the finished candle. The holes have a slight bevel that the cutting-edge may be the sharper and the candles may run through with greater ease. The workman draws the candles first through the larger hole, which takes off a portion, then through a smaller one, which removes more, and so on until the desired size is obtained for the finished candle. This operation improves the appearance as well as the burning of the candle. For dipping on a large scale there are some very convenient arrangements, as, for instance, a number of rods strung with wicks being arranged in a frame, which, by means of mechanical contrivances, are carried over pans in order to dip the wicks into the tallow and lift them out. Two methods are in use. The frames containing a number of rods with wicks are either sus- pended to supports standing alongside each other, as shown in Figs. 107, 108, and 109, and a trough filled with tallow is pushed backward and forward upon rails below the frames, or there is a MANUFACTURE OF CANDLES. 585 stationary tallow trough, as shown in Figs. 110 and 111, and the frames are advanced by means of a horizontal wheel on a vertical Fig. 107. Fig. 108. View. Side View. Fig. 109. Ground-Plan. A rails ; B, transportable furnace with lard-trough ; C, support with two frames ; D E, ropes with handles for pulling the frames up and down ; F, handles for moving the furnace. 586 MANUFACTURE OF SOAP AND CANDLES. Fig. 110. Ground-Plan. A, lard-trough in a furnace ; B, vertical shaft with horizontal wheel ; C D, hooks ; E, frames ; F, wicks ; G, ropes for lowering and raising the wicks. MANUFACTURE OF CANDLES. 587 shaft. The mode of operating these machines will be readily understood from the illustrations and explanations of the letters. Moulded candles. — By far the greater number of candles now manufactured are moulded, by which they acquire a much more finished appearance. The operation of moulding is performed by stretching the wick in the axis of a nearly cylindrical mould and pouring the liquid material around it. The moulds should be of a material which is a good conductor of heat and does not absorb fat. They were formerly made of cast-iron, sometimes lined with pewter, of tin, brass, and even glass, but at present an alloy of two parts tin and one part lead is almost exclusively used for their construction. The moulds are narrow, somewhat conical, tubes, highly polished internally in order to impart a smooth surface to the candle. They are bored out by machinery so that the interior shall be perfectly true. They vary somewhat in form, but as a rule each mould consists of two parts, the body B and the head-piece 0, fitting into the body as shown in Fig. 112. The head-piece is sometimes provided with a small stay, as shown in Fig. 113. Fig. 112. Fig. 113. Head-Pieces. Crochet-Hook., A, plate of the moulding table ; B, moulds ; C, head-piece; D, wick. The moulds made in this country are of a better form, and they are burnished by a vertical instead of a rotary motion, 588 MANUFACTURE OF SOAP AND CANDLES. which makes the candles easier to remove. The wicks are fixed in the longitudinal axis of the moulds by means of a long crochet-hook (Fig. 113), and secured by a peg at the "tip" and a cross-wire at the " butt" end of the candle. In moulding tallow-candles the temperature of the fat is of greater importance than in dipping, as it exerts an influence upon the expansion of the mould, thereby making the removal of the candle difficult. This danger appears when moulding too hot, while with the tallow too cold, bubbles and cavities are formed around the wick. The tallow should not be poured into the Fig. 114. View. Fie. 115. oooooooooooooo oooooooooooooo "oooooooooooooo 8 oooooooooooooo oooooooooooooo Ground-Plan. A, moulds ; J?, iron plate ; C, frame ; D, sheet-iron trough. moulds until a thin film has formed upon the surface, which is an indication of the tallow commencing to congeal. For moulding by hand a number of moulds with head-pieces MANUFACTURE OF CANDLES. 589 are suspended in holes of a frame, (7 (Figs. 114 and 115), covered with an iron plate, and on the bottom of which is a sheet-iron trough, D. According to an American method, the moulds without head- pieces are fixed in an iron plate, B (Figs. 116 and 117), which is secured to a wooden frame, A, provided with a bottom. The wicks are suspended to a wire, D, and the iron plate, B, is sur- rounded on three sides with stationary ledges, while that on the fourth side can be taken away in order to remove the fat from the table after moulding. Fiff. 116. Fig. 117. m T7 7 <7 7 V ■ n @ # ■ D = # c ® g @ - View. Ground- Plan. J., frame ; _B, iron plate ; C, moulds ; Z>, wire. After cooling, the candles are removed from the moulds and trimmed. This is best effected by means of a cutting apparatus, as shown in Figs. 118 and 119. The working of the apparatus will be readily understood from the illustrations and letters. The tedious method of moulding by hand has been almost everywhere superseded by moulding by machinery. A very conveniently-arranged machine for moulding tallow-candles is shown in Figs. 120 and 121. The moulds A are fastened by means of screws to a table upon which the plate (7, suspended by chains, can be lowered by means of the windlass and rope B. The mould-openings in the plate communicate with the funnels for the tallow. The wicks being strung upon rods, fluid-tallow is poured upon the plates to fill the moulds. When the candles 590 MANUFACTURE OF SOAP AND CANDLES. Fig. 118. Fig. 119. Cutting Apparatus. Longitudinal section. View. A } knife ; B, hinge ; C, box ; D, measuring board ; F, candles. are sufficiently cooled^ the plate is drawn up 7 and the candles cut off by means of a large hinged knife. They are then allowed Fig. 120. Fig. 121. IllllllUlltlllMl'lfllilll Moulding Machine for Tallow Candles. View. Side View. A, moulds ; B, windlass ; C, plate ; B, chains ; F, finished candles ; F, box. MANUFACTURE OF CANDLES. 591 to drop into the box F, which is provided with corresponding holes, and covered to protect the candles from dirt. Morgan's moulding machine, used in England for tallow can- dles, is so constructed that, with a sufficient number of stands, the moulding can be continued for an indefinite period, and at a saving of labor and time. The wicks in this machine are threaded through the moulds at the same time and by the same action as that which expels the candles. Fig. 122 shows the end elevation, and Fig. 123 a front view; Fig. 124 the plan, and Fig. Fig. 122. Fig. 123. f^ 125 the elevation of the back opposite Fig. 123. A represents the vessel or reservoir .containing the fat ; B a series of moulds. Fig. 124. Fig. 125. B Fig. 126 shows the range of moulds constructed in a peculiar manner. Fig. 127 shows the upper end of one of these moulds, and Fig. 128 a plan view of the same. It will be seen that the top consists of several pieces : 6 1 is a portion of the cylindrical 502 MANUFACTURE OF SOAP AND CANDLES. side of the mould ; b 2 the movable portion. This latter b 2 is hollow for the passage of the wicks, and fits closely to b l when the tallow is poured in. But as soon as the candle is cold, and in a condition to be removed, instead of being drawn out in the Fig. 126. Fig. 127. Fig. 129. Fig. 128. usual way, it is by this apparatus forced out by pressure applied to the extremity of the part, b 2 , which, following the course of the candle as it is forced from the mould, rewicks the mould for another candle. In Fig. 126 is shown a hollow cylinder b b, holding the bobbins of wick revolving on a shaft passing through its length. Fig. 129 exhibits a series of nippers opening and shutting by the action of the lever e holding the wicks (at the end and oppo- site to that of its entrance) in b 2 in a perpendicular position. To work this apparatus, we suppose a frame of moulds B regularly wicked and in the position at B 1 , Figs. 123, 124, 125, where the case is supported perpendicularly on the small straight edges of a railway, dd, Fig. 124. In this position, they are run forward until they come under the reser- voir A, when the tallow is applied in the usual manner. The moulds being filled are run along the railway dd to harden. When the candles are perfectly congealed, the moulds are brought to the position shown at B (Fig. 124), when they are placed on a railway similar to that shown at dd on the other side of the machine. Here they are pushed forward until they arrive at the hanging table D, which vibrates on the joint ee, and is then let down, but immediately returned to the longitudinal position MANUFACTURE OF CANDLES. 598 given at D, Fig. 124. The moulds B are moved until they arrive at the series of rammers E, as separately shown in Fig. 131, where the cylindrical case bb is removed by turning the jointed frame, as seen in Fig. 132, to be out of the way of the Fiff. 130. Fig. 131. Fie. 132. T3^ 4 rammer E. This series of rammers E moves freely in a hori- zontal direction, supported on straight edges at each extremity, and is moved by the partial rotation of the wheel C, as shown in Fig. 122, where /shows a band or chain passing over its peri- phery, and round the guide-pulley/ 1 . This chain or band/ is attached to a series of rammers E, so that the pressing of the lever c 1 which is fixed on the axis of the wheel C imparts motion to the rammers E in a horizontal direction. The moulds being in the position shown in Fig. 132, the next thing to do is to bend down the lever c 1 , thereby forcing the series of rammers E into contact with the sliding part b l of each of the moulds, and thereby pushing out the candles which are received into the grooved table F, raised up in exact position to receive them by the action of the scroll-piece c 2 attached to the wheel C, and on which the grooved table F is supported. The candles being forced from the moulds by the rammers are immediately secured and held stationary by depressing the lever G, which is provided with a series of like number of small convex pieces of pewter, formed of a section of the candle-moulds, which are attached to slight springs, as seen in Fig. 123. The lever is held down by a small catch. From what has been said of the frame of moulds B, it is obvious that the same action of the rammers E, which displaces the candles, will carry down to the moulds a fresh 38 594 MANUFACTURE OF SOAP AND CANDLES. supply of wicks for the succeeding candles, and, at this period, while the finished candles are secured on the table F, the nipper /, shown at Fig. 129, must be reapplied, after which the finished candles are cut off, and disposed of. The next duty of the operator is to replace the lever c 1 in the position shown at Fig. 122, which carries back the rammer E along with the sliding top of the moulds to their former position, and the moulds are wicked ready for a fresh supply of tallow. This series of rammers E is formed of separate hollow tubes, supported in the cross-piece g g, each of which tubes is provided with a small spring having a slight projection on its inside by means of which, when the rammers are pressed against the sliding part of the moulds, marked b 2 , the spring gives way and catches firm hold of the notched part, as shown at Fig. 127. It is thereby enabled to bring it back to its former position, where the candles are forced from the moulds as soon as the rammers are retired, and have brought back the sliding tops b 2 of the respective moulds. The springs at their extremity, which had held b 2 , are relieved or lifted up by a series of rammers or rods, which pass up the interior of the hollow rammers, as already described. This second series of rods is fixed in a similar cross-piece marked hh in Fig. 124, which, as* soon as the rammers are retired from the moulds, is forced forward by means of the lever H, and thereby the caps and the whole of the moulds marked B are freed from any connection with the rammers E. At this period the moulds are passed forward to the railroad d d, and replaced at the position shown at B 1 , the tallow from the receiver A is again supplied to them, and the process already described repeated any number of times. The continuous wick machines for moulding tallow-candles are similar in construction to those used for stearin-candles, which will be described later on. The darkening of the flame by scales and consequent necessity of snuffing are a defect common to all tallow-candles. Tallow having a comparatively low melting point requires thick wicks. With the use of thin wicks, which bend over and are consumed by the flame, melting off on one side and consequent guttering of the candle are unavoidable. MANUFACTURE OF CANDLES. 595 It remains to mention the so-called plated candles, i. e., tallow- candles coated with a thin layer of wax, or of a mixture of tallow and wax, or of spermaceti, or stearic acid. Usually wax with or without an addition of tallow is used. Two methods are in vogue. By the first the mould, the lower end of which has been pre- viously closed, is filled one-fourth or one-third with melted wax, and after having closed the top, rolled upon a table. The stopper is then removed and the superfluous wax poured out. The mould, the sides of which are now covered by a coating of wax, is wicked and filled with tallow in the usual manner. Externally such candles have the appearance of wax-candles, but the wax being less fusible forms an edge on the burning wick which becomes the higher the purer the wax and the denser the layer of it. Hence, it is best to use a mixture of about equal parts of wax and tallow. The thickness of the coating, depending as well on the heat of the wax poured into the mould as on the outside tem- perature, varies very much. Its only purpose being, however, to remove the smeary external surface of a tallow-candle, it is best to make it as thin as possible, and, hence, the following method for which pure wax or mixed with 10 to 15 per cent, mutton suet is used, is to be preferred. Take a smooth steel cylinder fitting loosely into the candle-mould. Coat this cylinder with tallow or fat, and then dip it into melted wax, withdrawing it immediately, whereby it will be coated with a thin layer of wax. This shell, which can be readily removed from the cylinder, is placed in the mould, and the latter, after wicking, is filled with tallow in the usual manner. The warm tallow pressing the softened shell of wax against the sides of the mould secures a uniform smoothness of the exterior surface of the candle. The whiteness of the finished tallow-candles is improved by suspending them, especially in winter, in an airy room. Candles made from unbleached or gray tallow can be bleached by means of chlorine. The candles are hung, without touching each other, in a tight wooden box, and closing the lid hermetically, chlorine is gradually introduced. The box is provided with a pane of glass, through which the process of bleaching can be observed. When sufficiently bleached, the candles are rinsed off by dipping them in cold water and hung up to dry. 596 MANUFACTURE OF SOAP AND CANDLES. Stearin candles. — The principal raw materials used in the manu- facture of these candles are palm-oil and tallow, though in this country lard is largely used for this purpose. The researches of W. Heintz, which complete those made by Chevreul, have taught us that these fats consist of palmitic, stearic, and oleic acids, and glycerin. The acid which Chevreul designated as margaric acid has been proved to be a mixture of palmitic and stearic acids. The so-called "stearin candles" are frequently made of a mixture of stearin (i. e. y a mixture of palmitic and stearic acids), and soft paraffin. Candles of this description are known abroad as Apollo and Melamyl candles- The manufacture of stearin candles con- sists in two chief operations, viz: 1. The preparation of the fatty acids, and 2, the conversion of these acids into candles. The preparation of the fatty acids has been already described and illustrated in Part I., Chapter II. By careful melting experiments, Heintz has confirmed former observations, that a mixture of two solid fatty acids, which are homologous, has a lower melting point in certain proportions of mixture than each separate acid. During these melting experi- ments he observed also the properties of the congealed mixtures, and found that, while some are completely crystalline, others are entirely non-crystalline. On account of the importance of the subject, which gives to the manufacturer of stearin important points in regard to the nature and value of his products, we give Heintz's observations in the following: tables :— 1 . Myristic and la uric acids. A mixt ure of Myristic Laurie Melts Congeals Manner of congealing. acid. arid. at at C 14 H« 7 O.HO C 12 Ho 3 O.HO Degrees F. Degrees F. 100 parts parts 138.00 Scaly crystalline. 90 " 10 " 125.0 117.0 Same. 80 " 20 " 121.0 112.0 Extremely fine crystalline. 70 " 30 " 116.0 102.0 Same. 60 " 40 " 109.5 102.0 Non-crystalline. 50 " 50 " 99.0 96.0 Large- folia ted crystalline. 40 " 60 " 98.0 92.0 Non -crystalline. 30 " 70 " 95.0 90.0 Non- crystalline, woolly. 20 " 80 " 101.0 91.5 Same. 10 " 90 " 106.0 97.0 Needly crystalline. " 100 " 110.5 — Scaly crystalline. MANUFACTURE OF CANDLES. 2. Palmitic and myristic acids. 597 A mix „ure of Palmitic Myristic Melts Congeals Manner of congealing. acid, acid, at at C 1G H 31 O.HO C 14 H 27 O.HO Decrees F. Degrees F. 100 parts parts 143. 50 __ Scaly crystalline. 95 " 5 " 142.0 136.5 Same. 90 " 10 " 140.0 132.0 Same. 80 " 20 " 136.5 128.0 Scaly and indistinctly needly. 70 " 30 " 131.0 124.0 In extremely fine needles. 60 " 40 " 125.0 121.0 Non-crystalline, rugged. 50 " 50 " 118.0 113.5 Large-foliated crystalline. 40 " 60 " 116.5 110.5 Indistinctly foliated. 35 " 65 " 115.5 110.5 Non-crystalline, opaque. 32.5 " 67.5 " 115.0 111.0 Same. 30 " 70 " 115.0 110.5 Same. 20 " 80 " 121.0 106.0 Non-crystalline. 10 " 90 " 125.0 113.5 In long needles. " 100 " 129.0 — ■ Scaly crystalline. 3. Stearic and palmitic acids. A mixture of Stearic Palmitic Melts Congeals Manner of congealing. acid, acid. at at CwHsbO.HO C 16 H 31 O.HO Degrees F. Degrees F. 100 parts parts 156. SO __ Scaly crystalline. 90 " 10 " 153.0 144.5 Same. 80 " 20 " 149.5 140.5 Finely needly crystalline. 70 " 30 " 145.0 139.0 Same. 60 " 40 " 140.5 134.0 Non-crystalline, rugged. 50 " 50 " 134.0 131.0 Large-foliated crystalline. 40 " 60 " 133.0 130.0 Same. 35 " 65 " 132.0 130.0 Non-crystalline, wavy, lustrous. 32.5 " 67.5 " 131.0 129.0 Same. 30 " 70 " 131.0 129.0 Non-crystalline, wavy, lustreless. 20 " 80 " 135.5 129.0 Very indistinctly needly. 10 " 90 " 140.0 130.0 Beautifully needly crystalline. " 100 " 143.5 — Scaly crystalline. 598 MANUFACTURE OF SOAP AND CANDLES. 4 Stearic and myristic acids. A mixture of Stearic Myristic Melts Manner of congealing. acid. acid, at C 18 H 35 O.HO C 14 H 2 7 O.HO Degrees F. 100 parts parts 156 50 Scaly crystalline. 90 " 10 i i 153.0 Still more distinctly scaly crystalline. 80 " 20 a 149.0 Somewhat less distinctly scaly crystalline. 70 " 30 a 145.0 Still less distinctly scaly crystalline, no trace of needles. 60 " 40 ( i 139.5 Commencement of scaly crystallization, no trace of needles. 50 " 50 1 t 130.0 Non-crystalline, opaque. 40 " 60 i i 123.0 Beautifully large-foliated crystalline. 30 " 70 a 119.0 Foliated crystalline. 20 " 80 i : 118.0 Indistinctly crystalline. 10 " 90 a 125.0 Non-crystalline, opaque. " 100 i i 129.0 Scaly crystalline. 5. Palmitic and lauric acids. A mixture of Palmitic Lauric Melts acid, acid, at C 16 H 31 O.HO C 12 Ho 3 O.HO Degrees F. 100 parts parts 143.50 90 " 10 " 139.5 80 " 20 " 135.0 70 " 30 " 130.0 60 " 40 " 124.0 50 " 50 " 116.5 40 " 60 " 104.0 30 " 70 " 101.0 20 " 80 " 99.0 10 " 90 " 107.0 " 100 " 110.5 Manner of congealing. Scaly crystalline. Distinctly scaly crystalline. Somewhat less distinctly scaly crystalline. Still less distinctly scaly crystalline. Granular, indistinctly scaly crystalline. Almost entirely non-crystalline, opaque. Large-foliated crystalline. Small-foliated crystalline. Finely crystalline, indistinct. Non- crystalline. Scaly crystalline. 6. Stearic and lauric acids. A mixture of Stearic acid, Laurie acid, C 12 H 23 O.HO 100 parts 90 n 80 1 1 70 a 60 t i 50 1 1 40 a 30 a 20 n 10 a a parts 10 " 20 " 30 " 40 " 50 " 60 " 70 " 80 " 90 " 100 <{ Melts at Degrees F 15 6. 50 152.5 148.0 143.5 138.0 132.5 123.5 110.0 101.0 107.0 110.5 Manner of con^ealine:. Scaly crystalline. Distinctly scaly crystalline. Same. Distinctly granular crystalline. [zation. Granular, commencement of scaly crystalli- Nearly crystalline, slightly granular. Non-crystalline, warty. Upon the surface, areas of small shiny crys- Non-crystalline, warty. [tals. Non -crystalline. Scaly crystalline. MANUFACTURE OF CANDLES. 599 7. Margaric acid {from cyancetyl) and myristic acid. A mixture of Marararic Myristic Melts Manner of congealing. acid, acid, at C 17 H 33 O.HO C u H 27 O.HO Degrees F. 100 parts parts 140.00 Scaly crystalline. 90 " 10 " 135.0 Same. 80 " 20 " 132.0 Indistinctly crystalline. 70 " 30 " 128.0 Almost entirely non-crystalline with level 60 " 40 " 123.0 Amorphous, opaque. [surface. 50 " 50 " 115.0 Same. 40 " 60 " 114.0 Somewhat granular, crystalline. 30 " 70 " 112.5 Same, with larger grains. 20 << 80 " 120.0 Same, grains very indistinct. 10 " 90 " 125.0 Opaque, in scarcely perceptible concentric " 100 " 129.0 Scaly crystalline. [needles. 8. Margaric acid {from cyancetyl) and palmitic acid. A mixture of Margaric Palmitic Melts Manner of congealing. acid, acid. at - C 17 H 33 O.HO C 16 H 31 O.HO Degrees F. 100 parts parts 140.00 Scaly crystalline. 90 " 10 " 138.0 Same. 80 " 20 " 136.0 Same, though somewhat flowery. 70 " 30 " 134.5 Same. 60 " 40 " 134.0 Same. 50 " 50 " 133.0 Same. 40 " 60 " 133.0 Same. 30 " 70 " 134.5 Flowery, almost in long needles. 20 " 80 " 137.5 In long needles. 10 " 90 " 141.0 Same. " 100 " 143.5 Scaly crystalline. The mixtures of the above acids congeal partly like the pure acids, which contain 80 to 90 per cent, of palmitic acid, in beau- tiful long needles, in the same manner as the mixture of stearic and palmitic acids, formerly called margaric acid. 600 MANUFACTURE OF SOAP AND CANDLES. 9. Steai"ic and margaric acids {from cyancetyl). A mixture of Stearic Margaric Melts Manner of congealing. acid, acid, at C 18 H350.HO C 17 H ;a O.HO Degrees F. 100 parts parts 157.00 Scaly crystalline. 90 " 10 " 153.5 Same. 80 " 20 " 150.0 Same. 70 " 30 " 148.5 Same. 60 " 40 " 144.5 Same. 50 " 50 " 143.5 Same, but more pearly. 40 " 60 " 142.0 Same. 30 " 70 " 141.5 Same. 20 " 80 " 139.5 Same. 10 " 90 " 139.0 Same. " 100 " 140.0 Scaly crystalline. The mixtures of both fatty acids melt more freely than stearic acid, but only in a moderate degree more so than margaric acid. They congeal almost like unmixed fatty acids and also behave differently from the mixtures of stearic and palmitic acids. With a mixture of two fatty acids, the melting point of which is itself lower than that of each of the two acids, the melting point becomes still lower by adding a determined quantity of a third acid ; and, what is especially remarkable, even when this third acid has a greater atomic weight and higher melting point than the first two acids. The melting point of a mixture of 30 parts of palmitic acid and 70 parts of myristic acid is at 115.0° F., but it sinks still lower by adding to 20 parts of the mixture up to 7 parts of stearic acid. Palmitic, myristic and stearic acids. 20 parts of a mixture of 30 parts of palmitic acid and 70 parts of myristic acid. Stearic acid. Melts at Degrees F. Manner of con^ sealing. » 1 part 2 parts 3 " 4 " 5 " 115.00 113.0 112.0 111.0 111.0 112.0 Non-crystalline. n a 6 " 113.5 i i 7 " 115.0 «c 8 " 116.0 i i MANUFACTURE OF CANDLES. 601 The melting point of a mixture of 30 parts of myristic acid and 70 parts of lauric acid, which melts at 95.0° F., changes as follows by adding to 20 parts of the mixture 1 to 10 parts of palmitic acid. Myristic, lauric, and palmitic acids. 20 parts of a mixture of 30 parts of myristic acid aud Palmitic acid. Melts at Manner of congealing. 70 parts of lauric acid. Degrees F. 95.00 Non-crystalline. 1 part 93.0 ' 2 parts 91.5 3 " 90.0 4 " 91.0 5 " 93.0 6 " 94.0 7 " 95.5 8 " 96.8 9 " 99.0 Indistinctly fine needly. 10 " 102.0 Fine needly. The phenomena in melting together fatty acids are similar to those in metals. By fusing together two metals the melting point is frequently considerably lowered, and by adding a third or fourth metal the melting point sinks even below the boiling point of water. Bismuth, for instance, melts at 475° F., lead at 633° F., and tin at 455° F. ; an alloy of 2 parts of bismuth, 1 part of lead, and 1 part of tin, known as Rose's metal, melts at 200.75° F., and an alloy called Wood's metal, containing cad- mium as a fourth metal, melts at 154.4° F. The fatty acids obtained by any one of the methods described in Part I., Chapter II., possess nearly the same properties. They represent white, transparent, and quite coherent cakes, which are, however, not sufficiently pure for moulding candles. The edges of the cakes are often more or less colored and soft, owing to some oleic acid not having been pressed out, while the surface of the cakes is contaminated with oxide of iron and the hair of the press-bags. For purification the cakes are treated with dilute sulphuric acid and steam, as described on page 45. The properties of stearic acid in a mixture with palmitic acid varying from those of tallow, some modifications in the manufac- 602 MANUFACTURE OF SOAP AND CANDLES. ture of candles from it are required, this being already evident from the higher melting point (about 50° to 100° F.) of the mixture of acids and its tendency of assuming a large-foliated crystalline structure on cooling, in consequence of which the candles become brittle and rough and incline towards guttering in burning. This can be overcome by the addition of up to 2 per cent, of wax or up to 20 per cent, of the cheaper paraffin. The use of arsenious acid for this purpose must be condemned as being detrimental to health, because arseniuretted hydrogen, as well as some arsenious acid, is evolved during the burning of such candles. Generally, before pouring the mass into the moulds with stirring, it is cooled almost to the congealing point, whereby it acquires a cream-like appearance and passes later on into a close-grained state. The moulds must first be heated by steam, or in an oven, as cold moulds do not completely fill up, the result being streaked candles. Although mixtures of various fatty acids have a lower melting point, as shown by Heintz's tables, they are nevertheless to be preferred, as they give harder and more transparent candles and will stand an addition of neutral fats for the cheaper manufacture of candles, as, for instance, the English composite candles (a mixture of fatty acids with cocoa- nut-oil or bleached palm-oil previously subjected to pressure). Stearin-candles require a moderately tightly-plaited wick. In plaiting a twist is given to it which causes it to become unplaited in burning, and to twist itself out of the flame. The wick is composed of three threads (each thread having a suitable number of fine ones) ; one thread being shorter, and thus having a greater strain upon it than the others, gives a curvature to the whole point as soon as the melting of the candle allows it to have fair play. The wicks are soaked in one of the wick-mordants pre- viously mentioned. Moulding of stearin-candles by hand is only done in small factories, the first step being to melt the purified stearic-acid. To prevent it from being overheated and acquiring a brownish color, this operation is best performed in a tinned copper kettle, provided with a steam-jacket and discharge-cock, similar to the one shown in Fig. 133. The melted stearic-acid is stirred until it acquires a cream-like consistency. In the mean while the MANUFACTURE OF CANDLES. 603 moulder is made ready, the moulds wicked and arranged. For the more simple apparatus the same kinds of moulds with heads. Fig. 133. Melting-Kettle. Section. • A, copper kettle ; B, discharge-cock ; C, steam-pipe ; D, scoop. as described for tallow-candles (Figs. 112 and 113), are used. From 20 to 30 of such moulds are suspended in a copper casing A (Figs. 134 and 135), which sits in the box B, partially filled Fig. 134. Moulding Apparatus, Longitudinal Section. with water. The latter being heated to nearly 212° F. by means of the steam-pipe C lying on the bottom of B, the casing A is taken out as soon as the moulds have been heated to from 113° to 122° F., while the melting point of the fatty acid mixture lies between 131° and 133° F. The steam and air escape through the cock F. 604 MANUFACTURE OF SOAP AND CANDLES. The moulds, after having been heated to the above-mentioned temperature and removed from the water-box, are immediately Fig. 135. Moulding- Apparatus. Ground Plan. A, copper casing- ; J9, water-box ; C, steam- pipe ; E y moulds ; F, cock for escape of air and steam. filled with the cream-like stearic-acid, and placed where they can cool. With proper precautions the candles will be of uniform appearance, and can be readily drawn from the moulds. In large factories moulding machines are generally employed, so that the operation is performed uninterruptedly, the construc- tion of these machines being such that the reeled wick is drawn through the moulds while the candles remain joined together by a short piece of wick until after the moulding is complete, the candles when cold being taken from the moulds, and the wicks cut through to separate them. A continuous wick machine, much employed for candle-mould- ing, is shown in Fig. 136. The moulds, one hundred in number, are inclosed in the cast-iron box a ; these moulds are tubes open on each end. The tip forming the top of the candle is fastened to a tube of iron through which the wick passes. These tubes are fastened to the platform which is connected by a rack and pinion moved by the crank g. The wicks are reeled on bobbins inclosed in the lower case. Above the mould-case is placed an apparatus called a clamp, which grasps the finished candles as they are raised out of the moulds by the piston tubes. The clamp is made of hard wood lined with India-rubber, and acted upon by means of hinges and cranks. The mould-box is pro- MANUFACTURE OF CANDLES. 605 vided with suitable valves for the admission of hot or cold water, either to warm the moulds or cool them and the candles. Fig. 136. The method of using the machine is as follows : After having made the connection between the hot and cold water-pipes and the machine, and having connected the outlet-pipe with a drain, the machine is ready for wicking. The pistons are raised by turning the crank-handle g until the tips are level with the butt- ends of the candle-moulds, where they are held by a pawl catch- ing in the pinion. A fine wire, doubled and of sufficient length to go through the tip-mould and piston, is then inserted, and extended below the piston sufficiently to enable the operator to pass the end of the wick through the loop. This permits the cotton to be drawn up through the mould; it must then be secured in any convenient manner during the first filling. The crank g is then returned, the melted material poured in and the 606 MANUFACTURE OF SOAP AND CANDLES. operation is complete. When nearly cold the butt ends of the candles are shaved off with a tin-scoop or a wooden-spud. The clamp should be placed open over the machine ; the crank-handle g is then turned, and the candles are ejected into the open clamp. The latter is then closed so that each candle is held in its proper position. The crank-handle g is then returned to allow all the pistons to recede into their places : the wicks are thus held in a central position by the candles and the cotton-bobbins. The cotton should be slightly strained under the piston-plate. The melted material is again poured into the moulds to form a second batch ; when these are nearly set the wicks are severed under the clamp, and the first batch is removed from it. The temperature of the water in the machine is easily regulated by shutting off or admitting hot or cold water as required. The internal immersion pipes, situated inside the water-box and between the rows of moulds, are perforated. These machines occupy about three feet by two feet of space, and are made to mould candles from 1 pound each to 56 to the pound. It is also possible to make candles of two different diameters, or several different lengths, in the same machine. A polished appearance is given to the candles by alternately admitting hot and cold water into the water-box. The adjustment of the temperature needs special experience, the operator's fingers forming usually his only thermometer. The arrangement of continuous wick-machines is also ex- plained by the following illustrations. To attain an accurate centering of the wicks in moulding machines, Grotowski has constructed an apparatus, shown in Figs. 137, 138, 139, and 140. The apparatus consists of two side-pieces, A and B, and the middle piece C, which are pro- vided with accurately-adjusted grooves 0.31 to 0.47 inch deep. These three pieces (A, B, and C) rest upon the upper surface L of the moulding machine, so that they come not in contact with the moulding material, and always remain clean. They can only be engaged, by means of the hand, by pushing the side-pieces A and B inward, and laying the middle piece C, which is hinged so that it can be folded together, flat. In Fig. 138, A is disen- gaged, and B and C engaged, while in the cross section, Fig. 139, all are engaged, and in the cross section 140 all disengaged. MANUFACTURE OF CANDLES. 607 The pieces A and B are guided by the arms D and E, which at the same time carry the candle-moulds F. In raising or folding Fig. 137. Longitudinal Section. together the middle piece C, which is effected by means of the ring G, it is guided by the pins H, which also form a seat for Fig. 138. —rv-v^-^rv-v-^V'^V^r^^ 3K Ground Plan. the candle-mould F. The springs / secure the middle piece C when raised up, while the springs K hold the side-pieces A and 608 MANUFACTURE OF SOAP AND CANDLES. B in every desired position. By a slight pressure upon the raised middle piece C, the latter slides down, and rests flat upon the upper surface L of the moulding machine. Fie. 139. Cross Section. When the three pieces A, B, and C are engaged, all the wicks are squeezed into the grooves, which are accurately adjusted to Fiff. 140. Cross Section. A, Bs side-pieces; C, middle-piece; I), E, guide-arms; F, candle-moulds; G, ring ; H, seat and guide-pins ; /, K, springs ; L, upper surface of machine. the centres of the moulds. The melted material is then poured into the candle-mould, and, after cooling, the parts A, B, and C MANUFACTURE OF CANDLES. 609 are disengaged, in order to make the road clear for emptying the machine. To effect an easy removal of the candles from the moulds, A. Iioyan has constructed a machine, shown in Figs. 141, 142, and 143, which conducts cold and warm water to the walls of the moulds, the former for the purpose of quickly cooling the mate- rial in the moulds, and the latter for the easy removal of the candles from them. The frame of the machine carries two columns, A, around which are guided two plates, B, connected by the rod C. Into the plates B catch the ends of two racks, D, which are moved up and down by means of the crank E and the cog-wheels F and G. On the cross bars C are brackets, TI, in which the ends of the wicks are secured. The moulding table contains only the copper mould-carriers J, in the centre of which are secured the tin moulds K. A trough, L, running the entire length of the machine, contains warm water. From this trough several tubes, M, enter a long pipe, N, containing a second pipe, provided with holes, which, by a turn of the crank 0, can be brought opposite the branches P, so that, by a single turn of 0, the supply of water can be simultaneously conducted through P to five moulds, which form a series, or interrupted. The cold water is conducted through the pipe Q, from which branches R lead to the moulds. The frame carries the bobbins F. After the moulds are wicked, the melted candle material is poured in and cooled by conducting cold water through the pipe Q. The cold water is then shut off, and after discharging that contained in the mould-carrier J through the cock T, hot water is admitted by a turn of the crank 0, whereby the metal-moulds K quickly expand. If, now, by a turn of the crank E, the cross bars C with the wicks fastened to them are raised up, the candles are removed from the moulds. Fig. 141 gives only the two ends of the machine, and shows only one-half of the longitudinal section and one-half of the longitudinal view. The moulding machine patented by A. Motard & Co., of Berlin, is a very neat and practical arrangement, as it overcomes many of the evils of the manufacture of candles by the customary 39 610 MANUFACTURE OF SOAP AND CANDLES. separation of the manipulations of moulding and cutting off and regulating the weight. Some of these evils are that, in remov- ing an excess of material, the ends of the candles frequently Fi and cold water, 67, 68 theory of the detergent action of soap, 75 Koettstorfer's method of testing fats by the saponification equivalents, 90 Krull's soap-cutter, illustrated and described, 264-266 LAKES, salt, in the United States, 172-174 Lanolin, 123 Lard, 119, 120 adulterations of, 119, 120 constituents of, 119 elementary composition of, 25 from diseased animals, 120 iodine degree of, 119 oil, characteristics and uses of, 119 rendering of, 119 saponification equivalent, 119 specific gravity of, 119 use of, in soap-making, 120 for white curd-soaps, 349 Latroni, 171 Laurie acid, crystallization of, 28 formula of, 27 specific gravity and melting point of, 28 and myristic acids, melting and congealing points of mixtures of, and manner of congealing, 596 and palmitic acids, the melting point of mixtures of and the manner of congealing, 598 and stearic acids, the melting point of mixtures of, and their manner of congealing, 598 Laurie — myristic, and palmitic acids, the melting point of mixtures of, and their manner of congeal- ing, 601 Laurin, laurostearin, characteristics of, 35 Laurot's oil-balance, 84, 85 Lavender-oil, 533, 534 Lead oleate, characteristics of, 32 Leblanc, death of, 21 Leblanc's discovery of producing soda from common salt, 21 method of manufacturing soda from common salt, 176 soda patent, and ruinous treat- ment by the French revolu- tionists, 21 Leeds, Albert R., scheme for the analysis of soap, 547-550 Lefebvre's oleometer, illustrated and described, 84 Lemon-soap, formula for, 515 Lemons, oil of, 534 Lettuce-soap, formula for, 518 Light by the candle, evolution of, 553-560 Lily-soap, formula for, 51& Lime, 214-216 burning, 214, 215 caustic, table of content of, in milk of lime, 234 yield of milk of lime from, 23.'i detection of, in water, 213 early use of, to strengthen alka- lies, 17 effect of, in the boiling, 440 its form and action in nature's organization, 214 milk of, table of content of, caus- tic lime in, 234 particular remarks on its proper proportion, 430, 431 preservation of, 215, 216 pure, and commercial, character- istics of, 215 purification of melted fatty acids from, 41, 42 saponification of fat by means of, 39-45 with little, 48-52 soap "too high in" poor quality of, 440 solubility of, 215 table of per cent, of, in causticiz- ing potash, 23 & 660 INDEX. Lime — value of, in soap manufacture, 216 Limes, oil of, 534, 535 Limette-oil, 534, 535 Linoleie acid, formula and character- istics of, 33 Linseed- and cottonseed-oil, bleaching of, 79, 80 yield of soap from, 434 and palm kernel-oil soaps, 153 oil, 152-154 bone fat, and palm kernel- oil soaps, 154 elementary composition of, 25 in the manufacture of resin- soap, 154 iodine degree of. 152 potash-soaps from, 153 saponification equivalent, 152 saponification of, 153, 428 smooth soft soap from, 427- 431 ■soda-soaps from, 153 soft soap, process of boiling, 428, 429 solubility of, 152 source, characteristics, adul- terations, and uses of, 152 specific gravity of, 152 tests for purity of, 152 use of, in the manufacture of soap, 152, 153 utilizing the dark precipitate from bleached, 434, 435 Liquid glycerin-soap, 522, 523 Litmus, test for alkalies, acids, and salts, 199, 200 Liverpool-soap, 373 Lixiviation of crude soda, 177 of the ashes, 187, 188 Lockwood & Everett's steam-render- ing apparatus, illustrated and de- scribed, 114, 115 London, consumption of soap in, 212 . soap-boilers in 1637, forced pur- chases imposed upon, before being allowed to carry on their trade, 19 Lubricating oils, refining of, 78 Lye, average, calculating the strength of, 439 carbonization of, 177 Lye- content of soda and potash in, according to degrees Baume, 240 directions for manufacture of, by Chas. Tennant & Co., 224, 225 disadvantage of the cold process of preparing, 227, 228 from wood ashes, preparation of, 228, 229 kettle, illustrated and described, 220-222 preparation of, by use of steam, 225, 226 of, from the carbonates of alkalies, 222-224 potash, table of quantities of fat necessary for saponifica- tion, 295 testing a, 242 strong soda, testing of, 241 sub or spent, 302 tanks, illustrated and described, 222, 223 Lyes, 220-242 for soft soap, preparation of, 433 the cold process of saponifi- cation, 419, 420 from caustic soda, use of, in boiling, 406, 407 importance of, for soft soaps, 424 preparation of, 220-229 of, from caustic alkalies, 220-222 of the, for natural grain soft soap, 436 table of percentage of soda and potash in, 230, 231 showing the content of effec- tive alkali in, 237-239 testing the, 229 to determine the correct propor- tions of caustic alkali and alka- line carbonate in, 241 twofold importance of, 220 MACHINES and utensils for the manufacture of soap, 243-284 Madi-oil, source and characteristics of, 155 specific gravity of, 155 Magnesia, detection of, in water, 214 Mahwa butter, characteristics of, 137, 138 source of, 137 INDEX. 661 Mailho process of testing oils from the crucifera, 94 Manufacture of candles, 577-G28 of soap by the cold process, 415- 423 improvement in the, due to Leblanc's splendid process for producing soda from common salt, 21 some modern methods of, 298, 299 Marbling of soaps prepared by the eold process, 423 or mottling tallow soap, 306-308 Margaric acid, 30 and myristic acids, the melt- ing point of mixtures of, and their manner of con- gealing, 599 and palmitic acids, the melting point of mixtures of, and their manner of concealing, 599 and stearic acids, the melting point of mixtures of, and their manner of congealing, GOO Margarin, 162 manufacture of, 116 Marine-soap, formula for, 478 Marjoram-oil, 535 Marseilles-soap, average yield of, from olive-oil, 319 coloring of, 317 divisions, of the process in manufacturing, 316 factories in, 315 from olive- oil fatty acid, 320 industry of, in the ninth cen- tury, 19 per cent, of fatty acid in, 319 preparation of, 314-320 table of analyses of, 319 value of, in dyeing, 315 varieties of, 315, 316 Marshmallow-soap, formula for, 474, 514 Mategcek, Edward, table showing the yield of milk of lime in degrees Baume from caustic lime, 233 Materials for candles, 561-576 Maumene's process of testing fatty oils by concentrated sulphuric acid, 89, 90 Medicated soaps, formulas for, 525- 527 Medicated — toilet-soaps, shaving creams, etc., manufacture of, 469- 529 Medium grain-soap, formulas for, 437 Melanyl candles, 625, 626 Melsen's process of decomposing fat, 64 Melting points of fats, 85, 86 Mercurial-soap, 527 Mercuric nitrate, preparation of, 98 color reactions upon oils by, 98, 99 Milk of lime, table of content of caustic lime in, 234 yield of, from caustic lime, 233 Milled soaps, formulas for, 514-521 or toilet-soaps, French sys- tem of making, 489, 490 Millefieurs-soap, formulas for, 475, 517 Mills, soap, illustrated and described, 493-496 Milly candles, 38 Milly's patent for saponification of fats by high pressure, 38 process for decomposition of fats, 54 Mineral fats and oils, composition of, 24, 25 oils and mineral fats in a soap residue, tests for, 547 and resin-oil, detection of, in fat oils, 102-105 wax, or ozakerite, 566-568 Minor implements of the soap-fac- tory, illustrated and described, 278 Mirbane, oil and essence of, 536 Monoglyceride, chemical formula of, 26 Mono Lake, estimate of salts, 173 Monopolv of soap manufacture in England, 1622, 19 Monostearin, formula of, 27 Mordants for wicks, compounds for, 578 Morgan's moulding machine for tal- low-candles, illustrated and de- scribed, 591-594 Motard's combined moulding: and cutting apparatus, illustrated and described, 611-614 Mottled curd-soap, 303 soap, English, 365-367 Moulded candles, 587-595 662 INDEX. Moulded candles — cutting apparatus for, illus- trated and described, 589, 590 machinery for, illustrated and described, 589-594 Moulding and cutting, combined ap- paratus, illustrated and de- scribed, 611-614 apparatus for stearin-candles, il- lustrated and described, 603, 604 candles, American method, illus- trated and described, 589 by hand, illustrated and de- scribed, 588, 589 temperature of the fat for, 588 machines for tallow-candles, il- lustrated and described, 589- 594 of candles to avoid dipping, illus- trated and described, 614, 615 with plaster-of- Paris tips, il- lustrated and described, 615, 616 Moulds, candle, to affect an easy re- moval of the candles from, illustrated and described, 609- 611 for candles, illustrated and de- scribed, 587-595 Musk, 539, 540 soap, formula for, 475 Mutton-suet, elementary composition of, 25 tallow, 109 Myrica-wax, characteristics of, 574, 575 Myristic acid, formula of, 27 and lauric acids, melting and congealing points of mixtures of, and manner of congealing, 596 and margaric acid, the melting point of mixtures of, and their manner of congealing, 599 and palmitic acids, the melting and congealing points of mix- tures of, and the manner of congealing, 597 and stearic acids, the melting and congealing points of mixture of, and their manner of congealing, 598 Myristic— lauric, and palmitic acids, the melting point of mixtures of, and their manner of congeal- ing, 601 palmitic, and stearic acids, the melting point of mixtures of, and their manner of congeal- ing, 600 Myrtle-tallow, characteristics of, 574, 575 \[APHTHOL-SOAPS, 525 _1 Naples shaving cream, 522 soft-soap, 478 Narbonne soda, 175 Natrona refined saponifier, 45, 228 Natural grain-soap, boiling of, 439- 441 with stearin, 442 soaps, 463-466 formulas for, and me- thod of boiling, 463- 466 materials for, 463 result of a chemical ex- amination of, 463 special attention requi- site, 438 soft-soap, 435-437 lyes for, 436 soda, 1 71-175 occurrence of, 171 Neat's foot-oil, 123, 124 Neroli- or orange-flower oil, 535 Neutral curd-soaps, 456-459 soap (nearly)' formula for, 458, 459 soaps, decomposition of, by wa- ter, 71 non-saponification of, 72 Nicias, author of the fuller's art, 17 Niger-oil, source and uses of, 154 specific gravity of, 154 Nitrobenzole, 531 Nitrous acid, vapors of, oils effervesc- ing and developing, 99-101 Non-caustic solution of crystallized soda, substitute for caustic lyes of soda-ash, in making toilet-soap, 513 Non-drying oils, 24 Non-saponifiable oil in a fat, pro- cesses to determine the amount of, 102-105 INDEX. 663 Non-saponified alkali, determination of, in a soap, 545 fat, determination of, 543 test of, in the soap- paste, 301 Non-saturated fatty aeids, groups con- taining the, 91 iodine combinations with, 91 Non-volatile fatty acids, 293 Normal acid solutions, 199-201 alkali solutions, 199-201. caustic-soda solution, 201 soaps, 299 Nutmeg- oil, 535 OATMEAL-SOAP, 527 Ocuba-wax, 576 Oil and wood-ash, mixture of, as a salve for cutaneous diseases, 18 balance, Fisher's, 83 balances, unreliable results from, 84, 85 bleached with lye, precautions in working with, 433 fruits, direct saponification of, 299 neat's foot, 123, 124 of bitter almonds, adulteration of, and tests for, 530, 531 preparation and charac- teristics of, 530, 531 of cloves, 532, 533 of mace, 141, 142 of mirbane, 531 of nutmeg, 141, 142 or fat and potassium hydroxide, yield of, after saponifica- tion, 296 augmentation of, after sapo- nification with water, 297 content of, 296 soap, 47 7 smooth, formulas for, 467, 468 Oils and fats, bleaching of, 78-81 United States patents relating to, 633 of vegetable origin, 125-169 tests for foreign admixtures in, 102-105 color reactions of calcium disul- phide on, 95 of mercuric nitrate on, 98, 99 Oils, color reactions — of stannic acid upon, 96, 9 7 of sulphuric acid upon, 96 of syrupy phosphoric acid upon, 97, 98 Grace- Calvert's method of test- ing, 99-101 detection of free fatty acids in, 105 drying and non-drying, 24 elaidic test for, 89 expansion of, by heat, 24 for illuminating purposes, best means of refining, 7 7, 78 for lubricating purposes, refining of, 78 from cruciferae, Mailho's process of testing, 94 group divisions of, according to their mean saponification num- ber, 91 importance of determining the specific gravities of, 83 iodine combinations with, table of, 93 sedimentary, utilization of, 157 table of reactions of, by Crace- Cal vert's process, 99-101 of temperatures of, after treatment by Maumene's process, 90 testing of, for adulterations with colza-oil, 94 viscosity of, 83 Old German curd-soap. 300-303 Oleate, per cent, of oxide and acid in, 297, 298 Oleic acid, 159-162 characteristics of, 31, 32 contamination of, by pro- ducts of distillation, 62, 63 elimination of, from the soapy mass, 43 essential difference of, ob- tained by distillation from that obtained from saponi- fication, 62, 63 from stearin factories, per- centage yield of product from distillation, 63 manufacture of, 159-162 most advantageous method of freeing stearic acid from, 48 664 INDEX. Oleic acid — obtained by saponification with water and super- heated steam, adaptability of, for soda and potash soaps, 65 soaps, action of air upon, 73 solubility of the salts of, 32 specific gravity, melting and congealing points of, 31 tests for determining its saponifying ability, 1G1 use of, in direct boiling, 403 uses of, 162 acids occurring in fats, 31 Olein, augmentation of, after saponi- fication with water, 297 characteristics of, 35, 36 chemical equation of, 69 soap, boiling process. 467 lyes for, 466, 467 soaps, 331, 332, 466, 467 formulas for, 458, 466, 467 Oleomargarin, 116 Oleometer, Lefebvre's, illustrated and described, 84 Oleometers, 83, 84 Gobby's and Lefebvre's, 83, 84 standard temperature of, in Eng- land and in Europe, 83 Olive-kernel oil, 143 saponification number, 91 solubility of, 144, 145 oil, 142-145 average yield of soap from, 319 curd-soap (Marseilles), 314- 320 elementary composition of, 25 fatty acid, soap from, 320 for soap, source of supply, 315 for table use, 143 iodine degree, 144 preparation of, 143 pure, characteristics of, 144 residues, percentage yield of product, from distillation, 63 saponification equivalent of, 144 number, 91 soaps, formulas for, 458-461 Olive oil — specific gravity of, 144 test for adulteration of, 144 Olivine, 523 Omnibus-soap, formula for, 475 Orange flower-oil, 535 soap, formula for, 515 Oranienburg curd-soap, 353-355 Organoleptic methods of examining fats and fat oils, 82 Otoba butter, 142 Ox-tallow, elementary composition of, 25 Ozokerite, constituents of, 566, 567 occurrence of, 566 or mineral-wax, 566-568 PALE soap with small rye-like grain, formulas for, 437 yellow-soap with rice-like grain, formulas for, 437 Palmitate, per cent, of oxide and acid in, 297, 298 Palmitic acid, distillation and solu- bility of, 28 formula of, 27 melting point and specific gravity of, 28 salts of, 28 and lauric acids, the melting point of mixtures of, and their manner of congealing, 598 and margaric acids, the melting point of mixtures of, and their manner of congealing, 599 and myristic acids, the melting and congealing points of mix- tures of, and manner of con- gealing, 597 and stearic acids, quantitative determination of, 30 table of behavior of mixtures of, 30, 31 the melting and congeal- ing points of mixtures of, and their manner of congealing, 597 myristic, and lauric acids, the melting point of mixtures of, and their manner of congealing, 601 and stearic acids, the melt- ing points of mixtures of and their manner of con- gealing, 600 INDEX. 665 Palmitin and water, yield of, after decomposition, 296 augmentation of, after saponifica- tion with water, 297 chemical equation of, 68 composition of, 296 soap, 325, 326 Palm-kernel oil, 134-137 and linseed-oil soaps, 153 behavior in regard to saponification, 136 chief constituents of, 136 iodine degree of, 136 melting point of, 136 palm-oil, and resin- soap, 327 - preparation of, 134 purification of, appa- ratus for, illustrated and described, 134- 136 saponification equiva- lent of, 136 saponification of, 136 soap, 355 congealing of, 73 white curd-soap from, 347 Palm-oil, adulterations of, and tests for, 132, 133 and bone,fat, soap from, 323, 324 and resin, soap from, 324, 325 and tallow, saponification of, by means of barium hy- drate, 45 bleaching of, by agency of heat and air, 130 by chemical agents, 130, 131 boiling of, in England, 321 characteristics and yield of, 128, 321 chief constituents of, 128 commercial, variation in quality of, 131, 132 cotton-seed oil, and resin- soap, 327 household soap, 322, 323 illumination of its coloring substance, 128, 129 iodine degree of, 128 melting point of, 128 Palm-oil, melting — points of, after treat- ment with sulphuric acid and washing, 56 temperatures of, during distillation, 62 ordinarv melting point of, 56 percentage yield of product from distillation, 63 principal places of produc- tion of, 128 saponification equivalent of, 128 of, 128, 129, 133 saponified with sulphuric acid, fluid products of, 62 solid products of, 62 sediment, bleaching of, 132 extracting the oil from, 132 soap (curd), 320-322 preparation of, 320, 321 soaps, analyses of, 322 tallow, and resin-soap, 327 use of, in the manufacture of stearin, 134 oils, soaps from, 133 table of percentage of dirt, water, and neutral fat of, and the congealing point of the fatty acids obtained from them, 131, 132 soap for stock soap, 509 formula for, 477, 478 half, formulas and process of preparing, 510-514 wax, source, preparation, and characteristics of, 576 Paraffin and carnauba wax, melting point of a mixture of, 575 candles, 616-618 process of making, 617, 618 sizes of wicks for, 578 chemical attributes of, 566 different melting points of, 617 foundation of its commercial in- dustry, 561, 562 history of its discovery, 561 industry in Scotland, 563, 564 in the United States, 564- 566 purification of, 567 $66 INDEX. Paraffi n — Seligue's specifications in his patent, 561-563 soap, 527 Paris transparent shaving soap, 519 Parlor bougies, 626 Paste soaps, 356-374 characteristics and divisions of, 356 formulas for, with a yield of 250 to 275 per cent., 357- 361 manufacture of, with a large yield, 357 materials for augmenting, 357 preparation of lye for, 228 process of manufacture, 357- 361 resin, 367-369 with a yield of 300 to 350 per cent., 363-365 500 to 600 per cent., 369-373 Patchouli-oil, 535, 536 soap, formula for, 515 Patents relating to soap and candles issued by the government of the United States, 629-646 Payen and Wilson, apparatus for de- composition of fat by superheated water, 63, 64 Peanut-oil, iodine degree of, 146 saponification equivalent, 146 number, 91 source, characteristics, and uses of, 146, 14 7 specific gravity of, 146 use of, in the manufacture of soaps, 146, 147 " Pedesis," 75 Perfuming of soaps, oils and other materials used for, 530-540 Permanent hardness of water, 211 Peroxide of hydrogen as a bleaching agent for oils, 81 Peruvian balsam, 538, 539 Petroleum-soap, 527 • Phenolphthalein, preparation and characteristics of, 33 Photometres, the physical law upon which they are based, 559 Physical methods of examining fats and fat oils, 82-89 Pimento-oil, 536 Piney-tallow, source of, 138 Pipette, illustrated and described, 196 Plane, soap, illustrated and described, 272-274 Plated candles, process of manufac- turing, 595 Pliny's account of the use of soap by the Gauls, 18 Plodder, Boudineuse, illustrated and described, 497-499 compound helix continuous, il- lustrated and described, 499, 500 hydraulic, illustrated and de- scribed, 4 97, 498 soap, hand- power, illustrated and described, 496, 497 Plodders, soap, illustrated and de- scribed, 496-500 Polishing of candles, 622-625 Poppy-seed oil, elementary composi- tion of, 25 source, characteristics, and uses of, 156 Portugal-oil, 535 Potash, 187-192 and soda, alkalimetric test of, 194, 195 content of, in lye according to degrees Baume\ 240 determination of the effec- tive substance in, 202- 204 solutions, table of content of, in degrees, Baume, 232 table of percentage of, in lyes, 230, 231 testing of, 193-207 caustic, 192 commercial varieties of, 187 correct method of testing, 193, 194 crude, calcining of, 189 or lump, 188 examination of, by volumetric analysis, 204, 205 from potassium sulphate, 191, 192 from the carbonized residue of beet-root molasses, 189, 190 from wood ashes, occurrence and manufacture of, 187 from wool-sweat, 190, 191 incineration of the plants for, 187 INDEX. 667 Potash- lye, table of quantities of fat necessary for saponifica- tion with, 295 testing a, 242 or soda solution of unknown strength, to causticize, 23G, 237 or soft soaps, 286 percentage of lime to causticize, 234, 235 red American, 189 table of lime per cent, in causti- cizing, 236 silicate of, 218, 219 soaps, decomposition of, by so- dium salts, 74 dry, absorption of water from the air, 73 from pure linseed oil, 153 solutions, treatment of, as a fill- ing agent, 421 Potassium bichromate, bleaching fats and oils with, 80, 81 carbonate to prevent viscidity in soft soap, 438 chromate, Watt's process for re- gaining, 80, 81 hydroxide and oil or fat, yield of, after saponification, 296 oleate, absorption of water from the air by, 73 permanganate bleaching fats and oils with, 80 salt, characteristics of, 32 stearate, 30 absorption of water from the air by, 73 effects produced by a solu- tion of, in cold water, 68 sulphate, potash from, 191, 192 Precipitate from bleached linseed oil, 434, 435 Presses, soap, illustrated and de- scribed, 502-507 Prime white curd-soap, 345-352 Problems to be determined in the ex- amination of fats, 82 Pumice soaps, formulas for, 474, 488 Pumpkin-seed oil, saponification num- ber, 91 Pumps, soap, illustrated and de- scribed, 260-263 Pure soap, yield of, in making toilet soap, 513, 514 Purified Cameroon oils, 131 Purifying and refining fats and oils, 76-78 Purple or violet color for candles, 628 QUANTITATIVE determination of fatty acids, 105, 106 RAPE OIL, elementary composi- tion of, 25 oxygen consumed by, in combustion, 558 saponification number, 91 Rapole'in, 158, 159 Raw materials, auxiliary, 208-219 used in the manufacture of soap, 23-75 Reactions of oils according to Crace- Calvert, table of, 101 Red American potash, 189 color for candles, 628 Refining and purifying fats and oils, 76-78 of soda, 178 Regat, Pierre, patent granted by Louis XIV. to manufacture soap, 1666, 20 Regat' s proposition to make soap for French consumption from ex- clusively French materials, 1 9, 20 soap patent annulled in 1669, 20 Remelting crutcher, illustrated and described, 479-483 obtaining best results in, 483, 484 steam pressure best adapted for, 483 toilet soaps by, 477-489 Rendering of fats, United States patents relating to, 629-631 Rendering of tallow by addition of chemical agents, 111, 112 by direct steam, 111, 112 use of sulphuric acid in, 111 tallow by steam, 114-1 16 by the dry process, objec- tions to, 110 Residue of beet-root molasses, con- stituents of, 190 Residues found in commercial oils, 103 Resin, 164-169 and palm oil, soap from, 324, 325 artificial bleaching of, 168, 169 commercial grades of, 165 668 INDEX. Resin — curd-soap, 327-331 dark, 329, 330 soaps, 326-331 with, 351, 352 detection of, in wax, 570, 571 fats, fat oils, and fatty acids used in the fabrication of soap, 109- 125 grain soaps, fabrication of, 165- 168 in a soap, determining the amount of, 543, 544 in fats, detection of, 105 oil and mineral oils, detection of, in fat oils, 102-105 paste soaps, 367-369 saponification of, 165, 166 soap, American method of pre- paring, 167 combinations of, with other soaps, 326, 327 in the cold way, 168 manufactured with the as- sistance of linseed oil, 154 table of analyses of, 331 transparent, 373, 374 solubility of, 165 source and preparation of, 1 64, 165 yield of soap from, 434 Resins and fatty acids, 157-169 Ricinelaidic acid, characteristics of, 33 Ricinoleic acid, specific gravity and characteristics of, 33 Rock salt, analysis of, 216, 217 colors of, 216 decolorizing of, 216 Roman fullers, importance of the, 1 7, 18 Rose-leaf soap, extra fine, formula for, 518 shaving cream, 522 soap, formula for, 475 Rosemary oil, 537 Rotary soap pump, Hersey's patent, illustrated and described, 260-263 Rotondi's conclusions from his experi- ments, 70 experiments, results of, 70, 71 to determine the action of water upon soap, without dialysis, 70, 71 to determine the behavior of soaps towards water, 69- 74 Rotondi's — process of preparing a pure soap, 69 theory of the detergent proper- ties of soap, 75 Rousseau's " diagometer," 88, 89 Royan's machine to effect an easy removal of the candles from the moulds, illustrated and described, 609-611 Rumford's photometer, 559, 560 Russian saddle soap, 338, 339 Rutschman's automatic soap clipper, illustrated and described, 492 compound helix continuous plod- der, 499, 500 foot-power soap press, illustrated and described, 502, 503 soap mill, illustrated and de- scribed, 495, 496 Rypophagen soap, 522 QALICOR, 175 KJ Salicyclic soaps, 524 Salt, action of, on an aqueous solution of soap, 73 common, 216-218 direct conversion of soda from common, 178, 179 first production of soda from common, 175, 176 natural occurrence of, in nature, 216 refining of, 218 solubility of, 217 solutions, insolubility of soda- soaps in, 73 specific gravity of, 217, 218 Salting out the soap-paste obtained by "boiling with steam, 288, 289 the soap-paste, 301, 302 Salts of non-volatile acids, 29, 30 of oleic acid, solubility of, in water, 32 of palmitic acid, 28 of stearic acid, 29 Samples for analysis, manner of tak- ing, 205-207 Sand-soaps, formulas for, 488 to determine the amount of, in a fat or oil, 102 Sapolite, composition and use of, 450 Saponification by sulphuretted alka- lies, 298, 299 direct, of oil fruits, 299 INDEX. 669 Saponification — equivalent, determination of, 90, 91 in the examination of fats, 90, 91 of contaminated fats, preliminary process, 53 of fats, 36-41 at a temperature below the boiling point, 286 by high pressure, patented by Runge, 38 by means of lime, 39-45 by the cold process, 415-419 illustrated by chemical for- mulas, 68, 69 neutral effect of oxygen in the, 25 with potash lye and common salt, 74 of lyes for the cold process, 419, 420 of the fats with sulphuric acid and subsequent distillation of the fatty acids, 52-62 of the tallow, test of, 305 test of perfect, 40 time required to complete it, 53 vat, illustrated and described, 89, 40 with alumina, 45, 46 with lime, closed apparatus for, 40, 41 effect of, on the triglycerides, 298 noxious vapors from, 40, 41 with little lime, 48-52 with water and superheated steam, advantages of, 65 Saponified oleic acid, 159-161 Sassafras-oil, 537, 538 Saturated fatty acids, group including, 91 Savona, soap industry in, 19 Savon a la marechale, formula for, 517 a. la rose, formula for, 514 a la violette de Parone, 517 formula for, 514, 515 au bouquet, formula for, 516 aux fieurs d'ltalie, formula for, 514 de Crimee, formula for, 514 de guemauve, formula for, 514 de palme, formula for. 514 de riz, formula for, 516 Savon — hygi6nique, formula for, 517 Savonettes, 523 Schattenbach's apparatus for distilling fatty acids, illustrated and de- scribed, 58, 59 Scheele, discoverer of glycerin, 25 Schneider's apparatus for purifying palm-kernel oil, illustrated and de- scribed, 134-136 Scotland, paraffin industry in, 563, 564 Scouring and gall-soaps, 527, 528 Scraps, soap, remarks on remelting of, 484 Sebacic acid in the products of distil- lation of fat, 63 Sebacylic acid, 576 Sebate, per cent, of oxide and acid in, 297, 298 Sedimentary oils, utilization of, 157 Seligue's specifications in his patent for distillation of bituminous shale, 561-563 Sesame-oil, 154 elementary composition of, 25 iodine degree, 145 saponification number, 91 saponification of, 145, 146 equivalent, 145 source, characteristics, and uses of, 1 45 use of, in the manufacture of soap, 145 Shaving cream, 522 creams, toilet-soaps, medicated soaps, etc., manufacture of, 469-529 soap by the cold process, 518, 519 by the warm method, 519 soaps, formulas for, 518-520 Shea butter, characteristics of, 137 preparation of, 137 Shortening soap, agents used, 388 Silicate of potash, 218, 219 of soda, 218, 219 Silver-soap, 286 Sinclair's soap, preparation of, 339 Siphon for drawing off* the lye, illus- trated and described, 226, 227 Slabbing and barring machine, illus- trated and described, 268, 269 machine, illustrated and de- scribed, 270, 271 670 INDEX. Smooth curd-soaps, fabrication of, 341 with resin, 851, 352 elaidin-soap, formulas for, 447- 449 oil-soap, 467, 468 soft soap from linseed-oil, 427- 431 soaps, coloring of, 370 formula for, with water- glass, 371 for, with talc and water- glass filling, 371, 372 marbling of, by the forma- tion of a flux, 372, 373 transparent soft soap, 425-427 Soap analysis, 541-550 balls, 523 beating, object of, 319 boiling, object to be attained by, 341 bucket and dippers, illustrated and described, 278 cakes, finishing and polishing the, 507 creams, perfume for, 521 crutching machine, illustrated and described, 275-277 cutter, Krull's, illustrated and described, 263-266 cutting by hand, illustrated and "described, 263, 264 frames, iron, with adjustable wires, illustrated and de- scribed, 265-268 machine, illustrated and de- scribed, 263-268, 500, 501 United States patents rela- ting to, 635, 636 factories, general plans of, 278- 284 factory, with the use of steam, general plan of a, illus- trated and described, 280, 281 with the use of superheated steam, ground plan of, il- lustrated and described, 281, 282 working with an open fire, general plan of a, illus- trated and described, 278- 280 frames, 255-260 from palm oil and bone fat, 323, 324 Soap — from palm oil and resin or colo- phony, 324, 325 mills, illustrated and described, 493-496 modern methods of manufacture, 298 paste obtained by steam boiling, salting out the, 288, 289 testing the saponification of, 301 planes, illustrated and described, 272-274 plodders, illustrated and de- scribed, 496-500 press, foot power, illustrated and described, 502, 503 hand, illustrated and de- scribed, 502 steam, illustrated and de- scribed, 505-507 presses, illustrated and described, 502-507 pumps, illustrated and described, 260-263 residue, determining the soluble portion of, 547 scraps, remarks on the melting of, 484 scum, yield of, in making toilet soap, 513, 514 stamping press, with box and dies, illustrated and described, 502, 503 stripper or clipper, illustrated and described, 490, 491 United States patents relating to, 633-643 Soaps, decomposition of, chemists opinions in regard to, 68 for the textile industries, 452- 468 of commerce, general components and characteristics of, 67 Soda, 171-186 adulterations, and test for, 181 and potash, alkalimetric test of, 194, 195 content of, in lye, according to degrees Baume, 240 determination of the effec- tive substance in, 202-204 solutions, table of content of, per degrees Baume, 232 table of percentage of, in lyes, 230, 231 INDEX. 671 Soda and potash — testing of, 193-207 and waterglass as a tilling agent, D DC' 382-385 and wood ashes, early use of, as detergents, 17 artificial, 175-179 carbonate of, calcining the, 177 caustic, 181-184 commencement of its manu- facture, 181, 182 importance of, to the soap boiler, 22 process of manufacturing, 182-184 process of testing, 1 93 commercial valuation of, 184-186 crude, lixiviation of, 177 crystallized, 180, 181 deposits of, in the United States, 171 direct conversion of, from com- mon salt, 178, 179 evaporation of, 177 from cryolite, 179 importance of, in soap manufac- ture, 432 lakes in the United States, 173, 174 lye, table of quantities of fat necessary for saponifica- tion with, 294 testing a strong, 241 D C ' non-caustic solution of crystal- lized, advantageous use of, in making toilet soaps, 513 occurrence of, in Europe, 174 or potash solution of unknown strength, tocausticize, 236, 237 percentage of lime to causticize, 234, 235 plants, supply of soda from, 174 production of, Irom common salt, 175, 176 production of, from common salt, discovered by Leblanc, 21 refining of, 178 silicate" of, 218, 219 soaps from linseed oil, 153 moist, effect of air upon, 73 soap, tallow, 361-363 table of lime per cent, in causti- cizing, 236 vegetable, 175 Sodium chloride solutions, table of specific gravity of, 218 Sodium — hydroxide and stearin, yield of, after saponification, 296 chemical equation of, 68 oleate, characteristics of, 32 chemical equation of, 69 oxide, comparative table of the actual per cents., accord- ing to English, French, and German degrees, 186 percentage of, found in the residues of the diffused and non-diffused soap Huids, 69, 70 stearate, 30 absorption of water by, on exposure to the air, 73 chemical equation of, 68 Soft soap, coloring and perfuming of, 441 description of, 424 filling materials for, 450 from hemp-seed oil, 435 from linseed oil, 427-431 from natural grain, 435-437 high reputation of German, 20 Naples, 478 of a very light color to ob- tain, 432,^433 principal materials used for, 424 smooth transparent, 425-427 storing of, 441, 442 to increase the yield and lathering of, 433 white, 449 with a mother-of-pearl lus- tre, 445-449 soaps, 424-451 filling of, 449-451 four varieties of, 425 of all kinds, fabrication of, 432 Soft toilet soaps, 520-523 Solar stearin, 119 Solid fats, general conditions of, 23, 24 vegetable fats, 125 Soluble glass, 218, 219 specific gravity of, 219 Solutions of soap, Rotondi's dialysis of, 69, 70 Solvay's process of direct conversion of soda from common salt, 178, 179 672 INDEX. Specific gravity of oil, oleometers for determining, 83, 84 Spent lye, 302 Spermaceti, 125 candles, 616-618 moulding of, 616 sizes of wicks for, 578 commercial, preparation and cha- racteristics of, 572, 573 principal source of, 572 Spinning of the soap, 301 Splitting of fats by water at a high temperature, 38 Stamping-press, soap, illustrated and described, 502-504 Standard soap solution, preparation of, 210 Stannic chloride, color reactions upon oils by, 96, 97 Steam boiling of fat, 288-290 jacket remelter, illustrated and described, 485, 486 kettle with double bottom, illus- trated and described, 521 soap-press, illustrated and de- scribed, 505-507 superheated, decomposition of fat by, 64-67 kettle for boiling with, illus- trated and described, 251- 255 Stearate, per cent, of oxide and acid in, 297, 298 Stearic acid, components and chemi- cal behavior of, 29 detection of, in wax, 570 factories, cooling apparatus for, illustrated and de- scribed, 46-48 first use of, as a material for candles, 38 formula of, 27 manufacture of, 37, 38 most advantageous method of freeing, from oleic acid, 48 salts of, 29 solubility of, 29 specific gravity of, 29 and carnauba wax, melting point of a mixture of, 575 and lauric acids, the melting point of mixtures of, and their manner of congealing, 598 and margaric acids, the melting point of mixtures of, and their manner of congealing, 600 Stearic — and myristic acids, the melting and congealing points of mix- tures of, and their manner of congealing, 598 and palmitic acids, quantitative determination of, 30 table of behavior of mixtures of, 30, 31 the melting and con- gealing points of mix- tures of, and their manner of congealing, 597 palmitic, and lauric acids, the melting point of mixtures of, and their manner of congeal- ing, 600 Stearin and sodium, yield of, after saponification, 296 augmentation of, after saponifica- tion with water, 297 candles, 596-616 behavior of a mixture of stearic and palmitic acids in the manufacture of, 30, 31 hand moulding of, 602 melting kettle for, illustrated and described, 602, 603 moulding apparatus for, il- lustrated and described, 603, 604 plaited wick for, 602 raw materials used in mak- ing, 596 sizes of wicks for, 578 characteristics of, 35 chemical equation of, 68 composition of, 296 natural grain-soap with, 442 solar, 1 1 9 Stettin palm-oil household soap, 322, 323 soap, preparation of, in the cold way, 323 Stock-soap, Heine's process of mak- ing, 299 palm- soap for, 509 soaps for milled toilet-soaps, 508, 509 Stone-ash, 189 Storing soft soap, 441, 442 Strassfurt salts, 191 Stripper, soap, illustrated and de- scribed, 490, 491 INDEX. 673 Strunz's crutching machine, illus- trated and described, 273-276 Sub-lye, 302 regaining of glycerin from, 310-314 utilization of, 308-310 Sugar, solution of, as a filling mate- rial, 422 Suint, percentage yield of product from distillation, 63 Suinter, 162 Sulphate of lime, detection of, in water, 213 Sulphur combinations, test for, in water, 213 oil, bleaching of, 143, 144 preparation of, 143 soaps, 525, 526 Sulphuretted alkalies, saponification by, 298, 299 Sulphuric acid added after mercuric nitrate, color reaction upon the liquid above the ni- trate precipitate, 99 bleaching fats and oils with, 79 color reactions upon oil by, 96 decomposition of neutral fats by, 38 detection of, in a fat or oil, 102 saponification of the fats with, and subsequent dis- tillation of the fatty acids, 52-62 testing of fatty oils with, 89, 90 use of, in bleaching, 80 use of, in rendering tallow, 111 Sulphurous acid, bleaching fats and oils with, 79, 80 Summer and Abert lakes, 173, 174 Sunflower-oil, source, characteristics, and uses of, 155, 156 Super-fat borax-soap, 525 camphor-soaps, 525 sulphur-soap, 525 iodine-soap, 525 naphthol-soap, 525 sulphur-soap, 525 salicylic-soap, 524 sulphur-soap, 525 tar sulphur-soap, 525 zinc salicylic-soap, 524 43 Superheated steam, advantages of sa- ponification by, 65 Sykes's patent wick-cutting machine, illustrated and described, 580- 582 Syrupy phosphoric acid, color reac- tions upon oils by, 97, 98 Szekso, occurrence of, 1 74 soda supply from, 174 TABLE for potash and lime calcu- lations in causticizing potash, 236 for the comparison of Baume's degrees with those of Twaddle, with specific gravities and statement of the percentage in soda and potash lyes at 59° F., 230, 231 giving; the content of soda and potash lye in kilogrammes- according to degrees Baume, 240 giving- the content of solutions of soda and potash according to degrees of Baume, 232 of analyses of Marseilles-soaps, 319 of pure palm-oil soaps, 322 of resin-soaps, 331 of rock salt, 216, 217 of behavior of mixtures of palm- itic and stearic acids, 30, 31 of degree of hardness in soap so- lutions, 211 of iodine combinations with oils r 93 of percentage of water, dirt, and neutral fat in palm-oils, and the congealing point of the fatty acids obtained from them, 131, 132 of reactions of oils according to Grace- Calvert, 101 of results obtained by testing fats and oils with glacial acetic acid, 88 of specific gravity of sodium chlo- ride solutions, 218 of the actual per cents, of sodium oxides according to English, French, and German degrees, 186 of the analysis of alkaline waters- of American lakes, 172 674 INDEX. Table— of the quantities of fat which a potash lye of Baume' s or Twaddle's degrees re- quires for saponification, 295 of fat which a soda lye of Baumee's or Twaddle's degrees requires for sa- ponification, 294, 295 of temperatures at which fat so- lutions become turbid, 88 of oils after treatment by Maumene's process, 90 showing the yield of milk of lime, in degrees Baume, from one kilogramme of caustic lime, 233 the percentage of oxides and hydroxides in caustic soda and caustic potash lyes, with the corresponding specific gravities and areo- meter degrees of Baume and Twaddle, 238, 239 Talc filling, preparation of and man- ner of mixing, 381, 382 in soap residue, test for, 547 use of, as filling agent, 422 "Talk," explanation of the term, 429 Tallow and palm oil, saponification of, by means of barium hy- drate, 45 beef, 109 bicuiba, 142 bleaching of, 116, 117 candles, machinery for moulding, illustrated and described, 589-594 wicks for, 577, 578 commercial, refining of, 116 constituents of, 117 contaminations of, 117, 118 (curd) soap, 303-308 detection of adulterants in, 117, 118 detection of, in wax, 570 dry process of rendering, 109- 114 fish, curd-soap from, 335, 336 hardening of, for candle dipping, 582 iodine, degrees of, 117 mutton, 109 myrtle, 574, 575 Tallow- objections to rendering, by the dry process, 110 oil, obtaining of, 116 old, purification of, 435, 436 oxygen consumed by, in combus- tion, 558 palm oil and resin soap, 327 piney, source of, 138 prime press, manufacture of, 116 purifying of, for making dipped candles, 582 rendering of, 109-119 by addition of chemical agents, 111, 112 by steam, 114-116 over an open fire, 112-114 saponification equivalents of, 117 of, 118, 119 soap, 477 advantages of, 303, 304 boiling process, 304, 305 manufacture of, with caustic soda lye, 306 marbling or mottling, 306- 308 preparation of the lye for, 304 process of salting out, 305, 306 smooth white, preparation of, 307, 308 soda soap, 361-363 steam rendering apparatus, illus- trated and described, 114-116 temperature of, for moulding candles, 588 test of its complete saponifica- tion, 305 to make inocuous the vapors de- veloped in the processs of ren- dering, 112 use of sulphuric acid in rendering, 111 virola, 142 Void's rendering apparatus over an open fire, illustrated and described, 112-114 wet process for rendering, 109, 114-119 Tallows, 109-119 pure, 117 Tank lyes, concentrating with caustic soda, 409 Tannin soap, 526 Tapers, wax, 620-622 INDEX. 675 Tar soaps, 524, 525 Temporary hardness of water, 211 Testing fatty acids with alcohol solu- tion of iodine and mercuric chloride, 92 of soda and potash, 193-207 oils, physical properties attempt- ed to be utilized in, 82 the lyes, 229 Test liquids, instruments for prepara- tion of, illustrated and described, 195-198 Tests of the purity of water, 213, 214 Textile industries, soaps for, 452-468 Theobromic acid, formula of, 27 Thompson's process of determining the presence of resin and mineral oils in fat oils, 102 Thyme oil, 538 Thymol soap, 526 Tiglic acid, formula of, 31 Tilghman and Bertholet, researches by, 38 Tilghman' s patent process for decom- position of fats by superheated water, 63 Tincture of ambergris, 540 of civet, 540 of musk, 540 Toilet soap, Heine's stock soap for, 299 kettle for rendering and re- fining, illustrated and de- scribed, 478, 479 to make a, equal to milled soap, 484, 485 soaps by remelting, 477-489 by the cold process, 473-477 by the warm process, 469 coloring of, 508 oils for, 22 or milled soaps, French sys- tem of making, 489, 490 shaving creams, medicated soaps, etc., manufacture of, 469-529 soft, 520-523 stock soaps for, 508, 509 superfine, formulas for, 516- 518 the best, preparation of, 470, 471 Total hardness of water, 211 Train oils, adulterations of, 124 and fish oils, 124, 125 application of the term, 23, 24 Train oils — in soap making, 125 purifying of, 124 soft soap from, 435 solubility of, 124 Transparent bougies, 626 glycerin soap, formula and pre- paration of, 472, 473 soft soap, 432-435 resin paste-soaps, 373, 374 soaps, 286, 470-473 soft soap, 425-427 Tribasic sodium oleate, chemical equa- tion of, 69 Tribouillet's distilling apparatus for fatty acids, illustrated and de- scribed, 59-62 Triglyceride, chemical formula of, 26 Triglycerides, after saponification with water, 296, 297 remnants of acid of, augmenta- tion of, 297 yield of, after saponification with lime, 298 with water, 297 Triolein, characteristics of, 35, 36 Tripalmitin, characteristics of, 35 Tristearin, characteristics of, 35 formula of, 27 Trona, 171 Turpentine-soap, 337, 338, 527 Twaddle and Baume, table of com- parative degrees of, 230, 231 Twisting of the wicks, machine for, illustrated and described, 578-580 UNITED STATES, soap industrv in, 20, 21 Unna (Dr. P. G.), medicated soaps prepared by, 524, 525 Urao, 171 Utensils and machines for the manu- facture of soap, 243-284 Utilization of sedimentary oils, 157 of sub-lye, 308-310 VALENTA'S, E., experiments with equal parts of oil and glacial acetic acid, 87, 88 process of testing animal and vegetable fats, 90 table of melting points of wax mixtures, 575 Vanilla-soaps, formulas for, 475, 476 676 INDEX. Vapors of nitrous acid, oils efferves- cing and developing, 99 Vaseline tar-soap, 526 Vateria fat, source of, 138 Vegetable fats, occurrence of, 76 fluid, 125 solid, most important of the, 25 various, found in tropical countries, 125 soda, 175 tallow from Borneo, 139, 140 source of, 138 waxes, 573-576 Venetian-soap, 314-320 Venice, soap industry of, in the fif- teenth century, 19 Vetivert-oil, 538 Violet-soaps, formulas for, 476 Virgin turpentine, 165 Virola- tallow, 142 Viscidity in soft soap, prevention of, 438 Viscosity of oil, 83 Vitivert-oil, 538 Vohl's rendering apparatus over an open fire, illustrated and described, 112-114 Volatile fatty acids, 27, 28 oils and other materials used for perfuming of soaps, 530-540 in a soap, determining the amount of, 546 Volumetric, analysis, 195 WARM pressure of the soap mass, 43, 44 Washing, ancient use of fuller's earth in, 17 of dirty garments regulated by Roman law, 18 the products of the action of sul- phuric acid,' 55, 56 Water, action of, on soap determined without dialysis, 70, 71 decomposition of the fats by, 63, 64 chemical composition of, 208 German, French, and English standard degrees of, hardness of, 212 glass, 218, 219 and soda as a filling agent, 382-385 Water glass — per cent, of fat to be used in boiling soap with, 408, 409 varieties and uses of, 421, 422 hard or soft, test for, 213 in soap, determining the content of, 541, 542 part performed by, in soap mak- ing, 208-216 physical properties of, 208, 209 purifying of, 213 to determine the amount of, in a fat or oil, 102 the hardness of, 209, 210 total, temporary, and permanent hardness of, 211 testing for copper in, 213 tests for the purity of, 213, .214 turbid or impure, purification of, 213 unequal affinity for, in soaps of various fats, 72, 73 Waters, hard and soft, action of, on soap, 209 Wax, adulterations of, and tests for, 570, 571 candles and wax-tapers, 618-622 basting of, illustrated and described, 618, 619 finishing and polishing of, 619, 620 press for, 620 roller for finishing, illustrated and described, 620 Carnauba, 575, 576 cowtree, characteristics of, 574 fig or Getah, 574 for candles, melting of, 618, 619 oxygen consumed by, in combus- tion, 558 palm, 576 soap, 345-352 soaps, requirements of, 342 tapers, 620-627 apparatus for making, illus- trated and described, 620- 622 white, characteristics of, 569, 570 Waxes, 568-576 of animal origin, 568-573 of vegetable origin, 573-576 Whale-fat, 335 Whitaker's remelter, illustrated and described, 486, 487 INDEX. 677 White alabaster-soap, formula for, 472 eurd-soap, boiling, with the use of direct steam, 348-351 formulas for, 349 from palm-kernel oil, 347 prime, 345-352 second quality, 351 elaidin-soap, formulas for, 446 ela'in, 162 fig-soap, 478 olive-oil soap, 460, 461 soap from cocoanut-oil, 509, 510 from cotton-seed oil, 347, 348 soft soap, 449 Windsor-soap, formula for, 477, 489 Wick, candle, materials for, 554 cutting machines, illustrated and described, 579-582 machine for candle moulding, continuously working, illus- trated and described, 604-606 mordants, compounds for, 578 Wicks and their preparation, 577-580 centering of, in moulding ma- chines, illustrated and de- scribed, 606-609 for tallow-candles, 577, 578, 594 for wax-candles, 618 materials used for, 577 twisting of the, machine for, il- lustrated and described, 578- 580 Wiederhold's method of detecting free fatty acids in oils, 105 Wild mango- oil, 141 W T ilson and Payen's apparatus for de- composing fats by superheated water, 63, 64 Wilson's superheated steam-distilling apparatus, illustrated and described, 64, 65 Window-glass resin, 165 Windsor shaving soap, 520 soaps, formulas for, 476, 477, 488, 489 Winter-green oil, 538 Wood-ashes, amount of, to be lixi- viated for conversion of tallow, 300 and natural soda, early use of, as detergents, 17 preparation of lye from, 228, 229 Wool-fat, characteristics and uses of, 414 constituents of, 123 distillation of, 123 purifying of, 123 soap, 334, 335 use of, in soap-making, 123 sweat (suint), 123 Wright and Fouche's apparatus for decomposition of fat by superheated water, 64 YELLOW artificial grain-soap, 443, 444 color for candles, 628 curd-soap, 355 dip turpentine, 165 elaidin-soap, formulas for, 446 resin curd-soap, 355 soap, formula for, 478 ZINC chloride, color reactions upon oils by, 95, 96 preparation of, 95 C^T^AXjOGKCTE OF poetical and Scientific Boo^ PUBLISHED BY Henry Carey Baird & Co INDUSTRIAL PUBLISHERS, BOOKSELLERS AND IMPORTERS, 810 Walnut Street, Philadelphia. &£" Any of the Books comprised in this Catalogue will be sent by mail, free of postage, to any address in the world, at the publication prices, J8®" A Descriptive Catalogue, 84 P a ges, 8vo., will be sent free and free of postage f to any one in any part of the world, who will furnish his address. Where not otherwise stated, all of the Books in this Catalogue are bound in muslin. AMATEUR MECHANICS' WORKSHOP: A treatise containing plain and concise directions for the manipula- tion of Wood and Metals, including Casting, Forging, Brazing, Soldering and Carpentry. By the author of the " Lathe and Its Uses." Seventh edition. Illustrated. 8vo. . . . $3.00 ANDRES.— A Practical Treatise on the Fabrication of Volatile and Fat Varnishes, Lacquers, Siccatives and Sealing Waxes. From the German of Erwin Andres, Manufacturer of Varnishes and Lacquers. With additions on the Manufacture and Application of Varnishes, Stains for Wood, Horn, Ivory, Bone and Leather. From the German of Dr. Emil Winckler and Louis E. Andes. The whole translated and edited by William T. Brannt. With 1 1 illustrations. l2mo. ....... $2.50 ARLOT.— A Complete Guide for Coach Painters: Translated from the French of M. Arlot, Coach Painter; for eleven years Foreman of Painting to M. Eherler, Coach Maker, Paris. By A. A. Fesquet, Chemist and Engineer. To which is added an Appendix, containing Information respecting the Materials and the Practice of Coach and Car Painting and Varnishing in the United States and Great Britain. T2mo. . . . #1-25 (0 HENRY CAREY BAIRD & CO.'S CATALOGUE. ARMENGAUD, AMOROUX, AND JOHNSON.— The Practi- cal Draughtsman's Book of Industrial Design, and Ma- chinist's and Engineer's Drawing Companion : Forming a Complete Course of Mechanical Engineering and Archi- tectural Drawing. From the French of M. Armengaud the elder, Prof, of Design in the Conservatoire of Arts and Industry, Paris, and MM. Armengaud the younger, and Amcroux, Civil Engineers. Re- written and arranged with additional matter and plates, selections from and examples of the most useful and generally employed mechanism of the day. By William Johnson, Assoc. Inst. C. E. Illustrated by fifty folio steel plates, and fifty wood-cuts. A new edition, 4to,, half morocco ......... $10.00 ARMSTRONG.— The Construction and Management of Steam Boilers : By R. Armstrong, C. E. With an Appendix by Robert Mallet, C. E., F. R. S. Seventh Edition. Illustrated. 1 vol. i2mo. 75 ARROWSMITH.— Paper-Hanger's Companion : A Treatise in which the Practical Operations of the Trade are Systematically laid down : with Copious Directions Preparatory to Papering ; Preventives against the Effect of Damp on Walls ; the various Cements and Pastes Adapted to the Several Purposes ot the Trade ; Observations and Directions for the Panelling and Ornamenting of Rooms, etc. By James Arrowsmith. 121110., cloth . • . . . $1.25 ASHTON. — The Theory and Practice of the Art of Designing Fancy Cotton and Woollen Cloths from Sample : Giving full instructions for reducing drafts, as well as the methods of spooling and making out harness for cross drafts and finding any re- quired reed; with calculations and tables of yarn. By Frederic T. Ashton, Designer, West Pittsfield, Mass. With fifty-two illustrations. One vol. folio . .-...-.. . . , .• .. $6.00 AUERBACH— CROOKES.— Anthracen : Its Constitution, Properties, Manufacture and Derivatives, including Artificial Alizarin, Anthrapurpurin, etc., with their applications in Dyeing and Printing. By G. Auerbach. Translated and edited fiom the revised manuscript of the Author, by Wm. Crookes, F. R. S., Vice-President of the Chemical Society. 8vo. . . $5.00 BAIRD. — Miscellaneous Papers on Economic Questions. By Henry Carey Baird. [In preparation.) 8AIRD. — The American Cotton Spinner, anc Manager's and Carder's Guide: A Practical Treatise on Cotton Spinning ; giving the Dimensions and Speed of Machinery, Draught and Twist Calculations, etc. ; with notices of recent Improvements: together with Rules and Examples ror making changes in the sizes and numbers of Roving and Yam. Compiled from the papers of the late Robert-H. Baird. i2mo. HENRY CAREY BAIRD & CO.'S CATALOGUE. BAIRD. — Standard Wages Computing Tables : An Improvement in all former Methods of Computation, so arranged that wages for days, hours, or fractions of hours, at a specified rate per day or hour, may be ascertained at a glance. By T. Spangler Baird. Oblong folio $5.00 BAKER. — Long-Span Railway Bridges : Comprising Investigations of the Comparative Theoretical and Practical Advantages of the various Adopted or Proposed Type Systems of Construction; with numerous Formulae and Tables. By B. Baker. i2mo. $1.50 BAKER.— The Mathematical Theory of the Steam-Engine : With Rules at length, and Examples worked out for the use of Practical Men. By T. Baker, C. E., with numerous Diagrams. Sixth Edition, Revised by Prof. J. R. Young. i2mo. . 75 BARLOW. — The History and Principles of Weaving, by Hand and by Power : Reprinted, with Considerable Additions, from " Engineering," with a chapter on Lace-making Machinery, reprinted from the Journal of the " Society of Arts." By Alfred Barlow. With several hundred illustrations. 8vo., 443 pages ..... $10.00 SARR. — A Practical Treatise on the Combustion of Coal: Including descriptions of various mechanical devices for the Eco- nomic Generation of Heat by the Combustion of Fuel, whether solid, liquid or gaseous. 8vo. ....... $2.50 BARR. — A Practical Treatise on High Pressure Steam Boilers: Including Results of Recent Experimental Tests of Boiler Materials, together with a Description of Approved Safety Apparatus, Steam Pumps, Injectors and Economizers in actual use. By Wm. M. Barr. 204 Illustrations. 8vo $3-00 BAUERMAN. — A Treatise on the Metallurgy of Iron : Containing Outlines of the History of Iron Manufacture, Methods of Assay, and Analysis of Iron Ores, Processes of Manufacture of Iron and Steel, etc., etc. By H. Bauerman, F. G. S., Associate of the Royal School of Mines. Fifth Edition, Revised and Enlarged. Illustrated with numerous Wood Engravings from Drawings by J. B, Jordan. i2mo $2.oc BAYLES. — House Drainage and Water Service : In Cities, Villages and Rural Neighborhoods. With Incidental Con> sideration of Certain Causes Affecting the Healthfulness of Dwell- ings. By James C. Bayles, Editor of " The Iron Age " and " The Metal Worker." With numerous illustrations. 8vo. cloth, #3.00 BEANS. — A Treatise on Railway Curves and Location of Railroads : By E. W. Beans, C. E. Illustrated. i2mo. Tucks . $1.50 BECKETT.— A Rudimentary Treatise on Clocks, and Watches and Bells : By Sir Edmund Beckett, Bart., LL. D., Q. C. F. R. A. S. With numerous illustrations. Seventh Edition, Revised and Enlarged. I2mo $2.25 HENRY CAREY BAIRD & CO.'S CATALOGUE. BELL. — Carpentry Made Easy: Or, The Science and Art of Framing on a New and Improved System. With Specific Instructions for Building Balloon Frames, Barn Frames, Mill Frames, Warehouses, Church Spires, etc. Comprising also a System of Bridge Building, with Bills, Estimates of Cost, and valuable Tables. 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Illustrated by nearly 200 engravings. 8vo. ........ $3.00 BIRD. — The American Practical Dyers' Companion: Comprising a Description of the Principal Dye-Stuffs and Chemicals used in Dyeing, their Natures and Uses ; Mordants, and How Made ; with the best American, English, French and German processes for Bleaching and Dyeing Silk, Wool, Cotton, Linen, Flannel, Felt, Dress Goods, Mixed and Hosiery Yarns, Feathers, Grass, Felt, Fur, Wool, and Straw Hats, Jute Yarn, Vegetable Ivory, Mats, Skins, Furs, Leather, etc., etc. By Wood, Aniline, and other Processes, together with Remarks on Finishing Agents, and Instructions in the Finishing of Fabrics, Substitutes for Indigo, Water- Proofing of Materials, Tests and Purification of Water, Manufacture of Aniline and other New Dye Wares, Harmonizing Colors, etc., etc. ; embrac- ing in all over 800 Receipts for Colors and Shades, accompanied by 170 Dyed Samples of Raw Materials and Fabrics. By F. J. 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Pp. 400. i2mo . • $2.50 BRANNT. — A Practical Treatise on Animal and Vegetable Fats and Oils : Comprising both Fixed and Volatile Oils, their Physical and Chemi- cal Properties and Uses, the Manner of Extracting and Refining them, and Practical Rules for^ Testing them; as well as the Manu- facture of Artificial Butter, Lubricants, including Mineral Lubricating Oils, etc., and on Ozokerite. Edited chiefly from the German of Drs. Karl Schaedler, G. W. Askinson, and Richard Brunner, with Additions and Lists of American Patents relating to the Extrac- tion, Rendering, Refining, Decomposing, and Bleaching of Fats and Oils. By William T. Brannt. Illustrated by 244 engravings. 739 pages. 8vo #7.50 BRANNT. — A Practical Treatise on the Manufacture of Soap and Candles : Based upon the most Recent Experiences in the Practice and Science ; comprising the Chemistry, Raw Materials, Machinc-v. and Utensils and Various Processes of Manufacture, including a great variety of formulas. Edited chiefly from the German of Dr. C. Deite, A. Engelhardt, Dr. C. Schaedler and others; with additions and lists of American Patents relating to these subjects. By Wm. T. Brannt. Illustrated by 163 engravings. 677 pages. 8vo. . . $7.50 BRANNT. — A Practical Treatise on the Raw Materials and the Distillation and Rectification of Alcohol, and the Prepara- tion of Alcoholic Liquors, Liqueurs, Cordials, Bitters, etc. : Edited chiefly from the German of Dr. K. Stammer, Dr. F. Eisner, and E. Schubert. By Wm. T. Brannt. Illustrated by thirty-one engravings. 121110. . . e . . . . #2.50 HENRY CAREY BAIRD & CO.'S CATALOGUE. QRANNT-WAHL.-The Techno- Chemical Receipt Book: Containing several thousand Receipts covering the latest, most *m portant, and most useful discoveries in Chemical Technology, and their Practical Application in the Arts and the Industries. Edited chiefly from the German of Drs. 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Illustrated by 185 wood en- gravings. 8vo. ........ $5.00 BYRNE. — Pocket-Book for Railroad and Civil Engineers: Containing New, Exact and Concise Methods for Laying out Railroad Curves, Switches, Frog Angles and Crossings; the Staking out of work; Levelling; the Calculation of Cuttings; Embankments; Earth- work, etc. By Oliver Byrne. i8mo., full bound, pocket-book form #i«75 BYRNE.— The Practical Metal- Worker's Assistant: Comprising Metallurgic Chemistry; the Arts of Working all Metals and Alloys; Forging of Iron and Steel; Hardening and Tempering; Melting and Mixing; Casting and Founding ; Works in Sheet Metal; the Processes Dependent on the Ductility of the Metals; Soldering; and the most Improved Processes and Tools employed by Metal- workers. With the Application of the Art of Electro-Metallurgy to Manufacturing Processes; collected from Original Sources, and from the works of Holtzapffel, Bergeron, Leupold, Plumier, Napier, Scoffern, Clay, Fairbairn and others. By Oliver Byrne. A new, revised and improved edition, to which is added an Appendix, con- taining The Manufacture of Russian Sheet-Iron. By John Percy, M. D., F. R. S. The Manufacture of Malleable Iron Castings, and Improvements in Bessemer Steel. By A. A. Fesquet, Chemist and Engineer. With over Six Hundred Engravings, Illustrating every Branch of the Subject. 8vo. ...... $7.00 BYRNE.— The Practical Model Calculator: For the Engineer, Mechanic, Manufacturer of Engine Work, Nava* Architect, Miner and Millwright. By Oliver Byrne. 8vo., nearly 600 pages $4-5& CABINET MAKER'S ALBUM OF FURNITURE". Comprising a Collection of Designs for various Styles of Furniture. Illustrated by Forty-eight Large and Beautifully Engraved Plates. Oblong, 8vo. . .•■••'. . . . . $3.50 CALLINGHAM. — Sign Writing and Glass Embossing: A Complete Practical Illustrated Manual of the Art. By James Callingham. i2mo $1.50 CAMPIN. — A Practical Treatise on Mechanical Engineering: Comprising Metallurgy, Moulding, Casting, Forging, Tools, Work* shop Machinery, Mechanical Manipulation, Manufacture of Steam- Engines, etc. With an Appendix on the Analysis of Iron and Iron Ores. By Fpancis Campin, C. E. To which are added, Observations on the Construction of Steam Boilers, and Remarks upon Furnaces used for Smoke Prevention ; with a Chapter on Explosions. By R. Armstrong, C. E., and John Bourne. Rules for Calculating the Change Wheels for Screws on a Turning Lathe, and for a Wheel- cutting Machine. By J. La Nicca. Management of Steel, Includ- ing Forging, Hardening, Tempering, Annealing, Shrinking and Expansion ; and the Case-hardening of Iron. By G. Edf. 8vg. Illustrated with twenty-nine plates and 100 wood engravings $5.00 HENRY CAREY BAIRD & CO.'S CATALOGUE. CAREY.— A Memoir of Henry C. Carey. By Dr. Wm. Elder. With a portrait. 8vo., cloth . . 75 CAREY.— The Works of Henry C. Carey : Harmony of Interests: Agricultural, Manufacturing and Commer- cial. 8vo. ..... . $1-5° Manual of Social Science. Condensed from Carey's " Principles of Social Science." By Kate McKean. i vol. i2mo. . $2.25 Miscellaneous Works. With a Portrait. 2 vols. 8vo. $6.00 Past, Present and Future. 8vo $2.50 Principles of Social Science. 3 volumes, 8vo. . . $10.00 The Slave-Trade, Domestic and Foreign; Why it Exists, and How it may be Extinguished (1853). 8vo. . . . $2.00 The Unity of Law: As Exhibited in the Relations of Physical, Social, Mental and Moral Science (1872). 8vo. . . $3.50 CLARK. — Tramways, their Construction and Working : Embracing a Comprehensive History of the System. With an ex^ haustive analysis of the various modes of traction, including horse- power, steam, heated water and compressed air; a description of the varieties of Rolling stock, and ample details of cost and working ex- penses. By D. Kinnear Clark. Illustrated by over 200 wood engravings, and thirteen folding plates. 2 vols. 8vo. . $12.50 COLBURN.— The Locomotive Engine : Including a Description of its Structure, Rules for Estimating its Capabilities, and Practical Observations on its Construction and Man- agement. By Zerah Colburn. Illustrated. 121110. . $1.00 COLLENS.— The Eden of Labor; or, the Christian Utopia. By T. Wharton Collens, author of " Humanics," " The History of Charity," etc. l2mo. Paper cover, $1.00; Cloth . $1.25 COOLEY. — A Complete Practical Treatise on Perfumery : Being a Hand-book of Perfumes, Cosmetics and other Toilet Articles. With a Comprehensive Collection of Formulae. By Arnold J. Cooley. i2mo. $1.50 COOPER.— A Treatise on the use of Belting for the Trans- mission of Power. With numerous illustrations of approved and actual methods of ar- ranging Main Driving and Quarter Twist Belts, and of Belt Fasten- ings. 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Illustrated by fourteen folding plates and several wood engravings. 743 pp. 8vo. $1000 CU SS A (JCE.— Practical Treatise on the Fabrication of Matches, Gun Cotton, and Fulminating Powder. By Professor H. Dussauce. i2mo. . . . . ^3 oc DYER AND COLOR-MAKER'S COMPANION: Containing upwards of two hundred Receipts for making Colors, on the most approved principles, for all the various styles and fabrics now in existence; with the Scouring Process, and plain Directions for Preparing, Washing-off, and Finishing the Goods. l2mo. $1 25 EDWARDS. — A Catechism of the Marine Steam-Engine, For the use of Engineers, Firemen, and Mechanics. A Practical Work for Practical Men. By Emory Edwards, Mechanical Engi- neer. Illustrated by sixty-three Engravings, including examples of the most modern Engines. Third edition, thoroughly revised, with much additional matter. 1 2 mo. 414 pages . . . $2 OQ EDWARDS. — Modern American Locomotive Engines, Their Design, Construction and Management. 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Illustrated, 8vo. . . . • |i oc FORSYTH.— Book of Designs for Headstones, Mural, and other Monuments : Containing 78 Designs. By James Forsyth. With an Introduction hy Charles Boutell, M. A. 4 to., cloth . . - #5 00 HENRY CAREY BAIRD & CO.'S CATALOGUE. 13 FRANKEI HUTTER.-A Practical Treatise on the Manu- facture of Starch, Glucose, Starch-Sugar, and Dextrine: Based on the German of Ladislaus Von Wagner, Professor in the Royal Technical High School, Buda-Pest, Hungary, and other authorities. By Julius Frankel, Graduate of the Polytechnic School of Hanover. Edited by Robert Hutter, Chemist, Practical Manufacturer of Starch-Sugar. Illustrated by 58 engravings, cover- ing every branch of the subject, including examples of the most Recent and Best American Machinery. 8vo., 344 pp. . $3.50 GARDNER.— The Painter's Encyclopaedia: Containing Definitions of all Important Words in the Art of Plain and Artistic Painting, with Details of Practice in Coach, Carriage, Railway Car, House, Sign, and Ornamental Painting, including Graining, Marbling, Staining, Varnishing, Polishing, Lettering, Stenciling, Gilding, Bronzing, etc. By Franklin B. Gardner. 158 Illustrations. i2mo. 427 pp $2.og GARDNER.— Everybody's Paint Book: A Complete Guide to the Art of Outdoor and Indoor Painting, De- signed for the Special Use of those who wish to do their own work, and consisting of Practical Lessons in Plain Painting, Varnishing, Polishing, Staining, P?^rr Hanging, Kalsomining, etc., as well as Directions for Renovating Furniture, and Hints on Artistic Work for Home Decoration. 38 Illustrations. i2mo., 183 pp. . $1.00 GEE. — The Goldsmith's Handbook : Containing full instructions for the Alloying and Working of Gold, including the Art of Alloying, Melting, Reducing, Coloring, Col- lecting, and Refining; the Processes of Manipulation, Recovery of Waste ; Chemical and Physical Properties of Gold ; with a New System of Mixing its Alloys ; Solders, Enamels, and other Useful Rules and Recipes. By George E. Gee. i2mo. . . $1.75 GEE.— The Silversmith's Handbook : Containing full instructions for the Alloying and Working of Silver, including the different modes of Refining and Melting the Metal; its Solders; the Preparation of Imitation Alloys; Methods of Manipula- tion ; Prevention of Waste ; Instructions for Improving and Finishing the Surface of the Work ; together with other Useful Information and Memoranda. By George E„ Gee. Illustrated. i2mo. $1.75 GOTHIC ALBUM FOR CABINET-MAKERS: Designs for Gothic Furniture. Twenty-three plates. Oblong $2.00 GRANT.— A Handbook on the Teeth of Gears : Their Curves, Properties, and Practical Construction. By George B. Grant. Illustrated. Third Edition, enlarged. 8vo. $1.00 GREENWOOD.— Steel and Iron: Comprising the Practice and Theory of the Several Methods Pur- sued in their Manufacture, and of their Treatment in the Rolling- Mills, the Forge, and the Foundry. By William Henry Green- wood, F. C. S. With 97 Diagrams, 536 pages. 121110. $2.00 14 HENRY CAREY BAIRD & CO.'S CATALOGUE. GREGORY. — Mathematics for Practical Men : Adapted to the Pursuits of Surveyors, Architects, Mechanics, and Civil Engineers. By Olinthus Gregory. 8vo., plates $3.00 GRIMSHAW.— Saws : The History, Development, Action, Classification, and Comparison of Saws of all kinds. With Copious Appendices. Giving the details of Manufacture, Filing, Setting, Gumming, etc. Care and Use of Saws ; Tables of Gauges ; Capacities of Saw-Mills ; List of Saw- Patents, and other valuable information. By Robert Grimshaw. Second and greatly enlarged edition, with Supplement, and 354 Illustrations. Quarto ....... $4.00 GRISWOLD. — Railroad Engineer's Pocket Companion for the Field : Comprising Rules for Calculating Deflection Distances and Angles, Tangential Distances and Angles, and all Necessary Tables for En- gineers; also the Art of Levelling from Preliminary Survey to tha Construction of Railroads, intended Expressly for the Young En- gineer, together with Numerous Valuable Rules and Examples. By W. GRISWOLD. l2mo., tucks $ J -75 GRUNER. — Studies of Blast Furnace Phenomena: By M. L. Gruner, President of the General Council of Mines oi France, and lately Professor of Metallurgy at the Ecole des Mines. Translated, with the author's sanction, with an Appendix, by L. D. B. Gordon, F. R. S. E., F. G. S. 8vo. . . . $2.50 Hand-Book of Useful Tables for the Lumberman, Farmer and Mechanic : Containing Accurate Tables of Logs Reduced to Inch Board- Meas- ure, Plank, Scantling and Timber Measure; Wages and Rent, by Week or Month; Capacity of Granaries, Bins and Cisterns; Land Measure, Interest Tables, with Directions for Finding the Interest on any sum at 4, 5, 6, 7 and 8 per cent., and many other Useful Tables. 32 mo., boards. 186 pages ...... .25 HASERICK.— The Secrets of the Art of Dyeing Wool, Cotton, and Linen, Including Bleaching and Coloring Wool and Cotton Hosiery and Random Yarns. A Treatise based on Economy and Practice. By E. C. Haserick. Illustrated by 323 Dyed Patterns of the Yams or Fabrics. 8vo . #12.50 HATS AND FELTING: A Practical Treatise on their Manufacture. By a Practical Hatter. Illustrated by Drawings of Machinery, etc. 8vo. . . #1.25 HOFFER. — A Practical Treatise on Caoutchouc and Gutta Percha, Comprising the Properties of the Raw Materials, and the manner of Mixing and Working them ; with the Fabrication of Vulcanized and Hard Rubbers, Caoutchouc ?„nd Gutta Percha Compositions, Water- HENRY CAREY BAIRD & CO.'S CATALOGUE. 15 proof Substances, Elastic Tissues, the Utilization of Waste, etc., etc. From the German of Raimund Hoffer. By W. T. Brannt. Illustrated i2mo. ........ $2.50 HOFMANN.-A Practical Treatise on the Manufacture of Paper in all its Branches : By Carl Hofmann, Late Superintendent of Paper-Mills in Germany and the United States ; recently Manager of the " Public Ledger " Paper Mills, near Elkton, Maryland. Illustrated by no wood en- gravings, and five large Folding Plates. 4to., cloth; about 400 pages .... #35.00 HUGHES. — American Miller and Millwright's Assistant: By William Carter Hughes. 121110 #1.50 HULME. — Worked Examination Questions in Plane Geomet- rical Drawing : For the Use of Candidates for the Royal Military Academy, Wool- wich ; the Royal Military College, Sandhurst; the Indian Civil En- gineering College, Cooper's Hill ; Indian Public Works and Tele- graph Departments ; Royal Marine Li engravings. 250 pages. 8vo. .... $2.50 SCHRIBER. — The Complete Carnage and Wagon Painter: .A Concise Compendium of the Art of Painting Carriages, Wagons, and Sleighs, embracing Full Directions in all the Various Branches, including Lettering, Scrolling, Ornamenting, Striping, Varnishing, and Coloring, with numerous Recipes for Mixing Colors. 73 Illus- trations. 177 pp. i2mo. . . . . . . $1.00 VAN CLEVE.— The English and American Mechanic : Comprising a Collection of Over Three Thousand Receipts, Rules, and Tables, designed for the Use of every Mechanic and Manufac- turer. By B. Frank Van Cleve. Illustrated. 283 pp. i2mo. #1.50 WAHNSCHAFFE.— Guide for the Scientific Examination of the Soil : By Dr. Felix Wahnschaffe. Translated from the German by William T. Brannt. Illustrated by numerous Engravings. 8vo. (In preparation.) GEORGE J. WHITEED ^■■■■:';:WmWB':h ■ ; ■ flRHJWBraJaora^^ STERLING & FRANCINE CLARK ART INSTITUTE NK1110 .B7 E stack Brannt, William T./A practical treat se 3 1962 00073 1046 Kcoioro JKK KK* >I>; KK>Z ' ml «& i i • ■ . I " ■. ■: » * •:■'■■•.■■'.■■■.■. . . . ,. ..,,,.;,.,..,.,.. , ... ■:•.:.•:•■ I :.,;■■■ ,,-,■.. ^ ■ • : ■ - . - • ....,.,..,. : .... . .: . . '.•:■-■■-■-■:: - ' ■ ■: - '..• ;. . ' I ! •..:•■' I ' .,'•.;-.■■:' - , : : : i\ -V :■ ■■ I S ( ' :.-.'■•''■- ■■'.'-■■'.,.• • ; K I ( •.:-::;■ : ; -, -. •. ( : • .•:.-•-• ........ ..... ...... .. . • ■ .■-.•: ; ; - . ,. ■:.-.■■;-::• • . ..... ....;...,.. - ■: i ! mm 1 *£#3