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diff --git a/21724-8.txt b/21724-8.txt new file mode 100644 index 0000000..3ef7298 --- /dev/null +++ b/21724-8.txt @@ -0,0 +1,10027 @@ +The Project Gutenberg EBook of The Handbook of Soap Manufacture, by +W. H. Simmons and H. A. Appleton + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: The Handbook of Soap Manufacture + +Author: W. H. Simmons + H. A. Appleton + +Release Date: June 7, 2007 [EBook #21724] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK THE HANDBOOK OF SOAP MANUFACTURE *** + + + + +Produced by Ben Beasley, Richard Prairie, Josephine Paolucci +and the Online Distributed Proofreading Team at +https://www.pgdp.net. (This file was produced from images +generously made available by The Internet Archive/Million +Book Project.) + + + + + + + + + +THE HANDBOOK OF + +SOAP MANUFACTURE + +BY + +W. H. SIMMONS, B.Sc. (LOND.), F.C.S. + +AND + +H. A. APPLETON + +_WITH TWENTY-SEVEN ILLUSTRATIONS_ + +LONDON +SCOTT, GREENWOOD & SON +"THE OIL AND COLOUR TRADES JOURNAL" OFFICES +8 BROADWAY, LUDGATE HILL, E.C. +1908 +[_All rights reserved_] + +Transcriber's note: + +For text: A word surrounded by a cedilla such as ~this~ signifies that +the word is bolded in the text. A word surrounded by underscores like +_this_ signifies the word is italics in the text. Greek letters +are translated into English and are in brackets, e.g. [alpha]. + +For numbers and equations: Parentheses have been added to clarify +fractions. Underscores before bracketed numbers/letters in equations +denote a subscript. + +Footnotes have been moved to the end of the chapter and minor typos have +been corrected. + + + + +PREFACE + + +In the general advance of technical knowledge and research during the +last decade, the Soap Industry has not remained stationary. While there +has not perhaps been anything of a very revolutionary character, steady +progress has still been made in practically all branches, and the aim of +the present work is to describe the manufacture of Household and Toilet +Soaps as carried out to-day in an up-to-date and well-equipped factory. + +In the more scientific portions of the book, an acquaintance with the +principles of elementary chemistry is assumed, and in this we feel +justified, as in these days of strenuous competition, no soap-maker can +hope to compete successfully with his rivals unless he has a sound +theoretical as well as practical knowledge of the nature of the raw +materials he uses, and the reactions taking place in the pan, or at +other stages of the manufacture. We also venture to hope that the work +may prove useful to Works' Chemists and other Analysts consulted in +connection with this Industry. + +At the same time, in the greater part of the book no chemical knowledge +is necessary, the subject being treated in such a way that it is hoped +those who are not directly engaged in the manufacture of soap, but who +desire a general idea of the subject, will find it of value. + +In the sections dealing with the composition and analysis of materials, +temperatures are expressed in degrees Centigrade, these being now almost +invariably used in scientific work. In the rest of the book, however, +they are given in degrees Fahrenheit (the degrees Centigrade being also +added in brackets), as in the majority of factories these are still +used. + +As regards strengths of solution, in some factories the use of Baumé +degrees is preferred, whilst in others Twaddell degrees are the custom, +and we have therefore given the two figures in all cases. + +In the chapter dealing with Oils and Fats, their Saponification +Equivalents are given in preference to Saponification Values, as it has +been our practice for some years to express our results in this way, as +suggested by Allen in _Commercial Organic Analysis_, and all our +records, from which most of the figures for the chief oils and fats are +taken, are so stated. + +For the illustrations, the authors are indebted to Messrs. E. Forshaw & +Son, Ltd., H. D. Morgan, and W. J. Fraser & Co., Ltd. + +W. H. S. +H. A. A. + +LONDON, _September_, 1908. + + + + +CONTENTS + + + PAGE + +CHAPTER I. + +INTRODUCTION. 1 + +Definition of Soap--Properties--Hydrolysis--Detergent Action. + + +CHAPTER II. + +CONSTITUTION OF OILS AND FATS, AND THEIR SAPONIFICATION 6 + +Researches of Chevreul and Berthelot--Mixed Glycerides--Modern Theories +of Saponification--Hydrolysis accelerated by (1) HEAT OR ELECTRICITY, +(2) FERMENTS, Castor-seed Ferment, Steapsin, Emulsin, and (3) CHEMICAL +REAGENTS, Sulphuric Acid, Twitchell's Reagent, Hydrochloric Acid, Lime, +Magnesia, Zinc Oxide, Soda and Potash. + + +CHAPTER III. + +RAW MATERIALS USED IN SOAP-MAKING 24 + +Fats and Oils--Waste Fats--Fatty Acids--Less-known Oils and Fats of Limited +Use--Various New Fats and Oils Suggested for Soap-making--Rosin--Alkali +(Caustic and Carbonated)--Water--Salt--Soap-stock. + + +CHAPTER IV. + +BLEACHING AND TREATMENT OF RAW MATERIALS INTENDED FOR + SOAP-MAKING 41 + +Palm Oil--Cotton-seed Oil--Cotton-seed "Foots"--Vegetable Oils--Animal +Fats--Bone Fat--Rosin. + + +CHAPTER V. + +SOAP-MAKING 45 + +Classification of Soaps--Direct combination of Fatty Acids with +Alkali--Cold Process Soaps--Saponification under Increased or Diminished +Pressure--Soft Soap--Marine Soap--Hydrated Soaps, Smooth and +Marbled--Pasting or Saponification--Graining Out--Boiling on +Strength--Fitting--Curd Soaps--Curd Mottled--Blue and Grey Mottled +Soaps--Milling Base--Yellow Household Soaps--Resting of Pans and +Settling of Soap--Utilisation of Nigres--Transparent soaps--Saponifying +Mineral Oil--Electrical Production of Soap. + + +CHAPTER VI. + +TREATMENT OF SETTLED SOAP 60 + +Cleansing--Crutching--Liquoring of Soaps--Filling--Neutralising, +Colouring and Perfuming--Disinfectant +Soaps--Framing--Slabbing--Barring--Open and Close +Piling--Drying--Stamping--Cooling. + + +CHAPTER VII. + +TOILET, TEXTILE AND MISCELLANEOUS SOAPS 77 + +Toilet Soaps--Cold Process soaps--Settled Boiled Soaps--Remelted +Soaps--Milled Soaps--Drying--Milling and Incorporating Colour, Perfume, +or Medicament--Perfume--Colouring matter--Neutralising and Superfatting +Material--Compressing--Cutting--Stamping--Medicated Soaps--Ether +Soap--Floating Soaps--Shaving Soaps--Textile Soaps--Soaps for Woollen, +Cotton and Silk Industries--Patent Textile Soaps--Miscellaneous Soaps. + + +CHAPTER VIII. + +SOAP PERFUMES 95 + +Essential Oils--Source and Preparation--Properties--Artificial and +Synthetic Perfumes. + + +CHAPTER IX. + +GLYCERINE MANUFACTURE AND PURIFICATION 111 + +Treatment of Lyes--Evaporation to Crude +Glycerine--Distillation--Distilled and Dynamite Glycerine--Chemically +Pure Glycerine--Animal Charcoal for Decolorisation--Glycerine obtained +by other methods of Saponification--Yield of Glycerine from Fats and +Oils. + + +CHAPTER X. + +ANALYSIS OF RAW MATERIALS, SOAP, AND GLYCERINE 117 + +Fats and Oils--Alkalies and Alkali Salts--Essential Oils--Soap--Lyes--Crude +Glycerine. + + +CHAPTER XI. + +STATISTICS OF THE SOAP INDUSTRY 140 + + +APPENDIX A. + +COMPARISON OF DEGREES, TWADDELL AND BAUMÉ, WITH ACTUAL DENSITIES 147 + + +APPENDIX B. + +COMPARISON OF DIFFERENT THERMOMETRIC SCALES 148 + + +APPENDIX C. + +TABLE OF THE SPECIFIC GRAVITIES OF SOLUTIONS OF CAUSTIC SODA 149 + + +APPENDIX D. + +TABLE OF STRENGTH OF CAUSTIC POTASH SOLUTIONS AT 60° F. 151 + + +INDEX 153 + + + + +CHAPTER I. + +INTRODUCTION. + + _Definition of Soap--Properties--Hydrolysis--Detergent Action._ + + +It has been said that the use of soap is a gauge of the civilisation of +a nation, but though this may perhaps be in a great measure correct at +the present day, the use of soap has not always been co-existent with +civilisation, for according to Pliny (_Nat. Hist._, xxviii., 12, 51) +soap was first introduced into Rome from Germany, having been discovered +by the Gauls, who used the product obtained by mixing goats' tallow and +beech ash for giving a bright hue to the hair. In West Central Africa, +moreover, the natives, especially the Fanti race, have been accustomed +to wash themselves with soap prepared by mixing crude palm oil and water +with the ashes of banana and plantain skins. The manufacture of soap +seems to have flourished during the eighth century in Italy and Spain, +and was introduced into France some five hundred years later, when +factories were established at Marseilles for the manufacture of +olive-oil soap. Soap does not appear to have been made in England until +the fourteenth century, and the first record of soap manufacture in +London is in 1524. From this time till the beginning of the nineteenth +century the manufacture of soap developed very slowly, being essentially +carried on by rule-of-thumb methods, but the classic researches of +Chevreul on the constitution of fats at once placed the industry upon a +scientific basis, and stimulated by Leblanc's discovery of a process for +the commercial manufacture of caustic soda from common salt, the +production of soap has advanced by leaps and bounds until it is now one +of the most important of British industries. + +_Definition of Soap_.--The word soap (Latin _sapo_, which is cognate +with Latin _sebum_, tallow) appears to have been originally applied to +the product obtained by treating tallow with ashes. In its strictly +chemical sense it refers to combinations of fatty acids with metallic +bases, a definition which includes not only sodium stearate, oleate and +palmitate, which form the bulk of the soaps of commerce, but also the +linoleates of lead, manganese, etc., used as driers, and various +pharmaceutical preparations, _e.g._, mercury oleate (_Hydrargyri +oleatum_), zinc oleate and lead plaster, together with a number of other +metallic salts of fatty acids. Technically speaking, however, the +meaning of the term soap is considerably restricted, being generally +limited to the combinations of fatty acids and alkalies, obtained by +treating various animal or vegetable fatty matters, or the fatty acids +derived therefrom, with soda or potash, the former giving hard soaps, +the latter soft soaps. + +The use of ammonia as an alkali for soap-making purposes has often been +attempted, but owing to the ease with which the resultant soap is +decomposed, it can scarcely be looked upon as a product of much +commercial value. + +H. Jackson has, however, recently patented (Eng. Pat. 6,712, 1906) the +use of ammonium oleate for laundry work. This detergent is prepared in +the wash-tub at the time of use, and it is claimed that goods are +cleansed by merely immersing them in this solution for a short time and +rinsing in fresh water. + +Neither of the definitions given above includes the sodium and potassium +salts of rosin, commonly called rosin soap, for the acid constituents of +rosin have been shown to be aromatic, but in view of the analogous +properties of these resinates to true soap, they are generally regarded +as legitimate constituents of soap, having been used in Great Britain +since 1827, and receiving legislative sanction in Holland in 1875. + +Other definitions of soap have been given, based not upon its +composition, but upon its properties, among which may be mentioned that +of Kingzett, who says that "Soap, considered commercially, is a body +which on treatment with water liberates alkali," and that of Nuttall, +who defines soap as "an alkaline or unctuous substance used in washing +and cleansing". + +_Properties of Soap._--Both soda and potash soaps are readily soluble in +either alcohol or hot water. In cold water they dissolve more slowly, +and owing to slight decomposition, due to hydrolysis (_vide infra_), the +solution becomes distinctly turbid. Sodium oleate is peculiar in not +undergoing hydrolysis except in very dilute solution and at a low +temperature. On cooling a hot soap solution, a jelly of more or less +firm consistence results, a property possessed by colloidal bodies, such +as starch and gelatine, in contradistinction to substances which under +the same conditions deposit crystals, due to diminished solubility of +the salt at a lower temperature. + +Krafft (_Journ. Soc. Chem. Ind._, 1896, 206, 601; 1899, 691; and 1902, +1301) and his collaborators, Wiglow, Strutz and Funcke, have +investigated this property of soap solutions very fully, the researches +extending over several years. In the light of their more recent work, +the molecules, or definite aggregates of molecules, of solutions which +become gelatinous on cooling move much more slowly than the molecules in +the formation of a crystal, but there is a definite structure, although +arranged differently to that of a crystal. In the case of soda soaps the +colloidal character increases with the molecular weight of the fatty +acids. + +Soda soaps are insoluble in concentrated caustic lyes, and, for the most +part, in strong solutions of sodium chloride, hence the addition of +caustic soda or brine to a solution of soda soap causes the soap to +separate out and rise to the surface. Addition of brine to a solution of +potash soap, on the other hand, merely results in double decomposition, +soda soap and potassium chloride being formed, thus:-- + + C_{17}H_{35}COOK + NaCl = C_{17}H_{35}COONa + KCl + potassium sodium sodium potassium + stearate chloride stearate chloride + +The solubility of the different soaps in salt solution varies very +considerably. Whilst sodium stearate is insoluble in a 5 per cent. +solution of sodium chloride, sodium laurate requires a 17 per cent. +solution to precipitate it, and sodium caproate is not thrown out of +solution even by a saturated solution. + +_Hydrolysis of Soap_.--The term "hydrolysis" is applied to any +resolution of a body into its constituents where the decomposition is +brought about by the action of water, hence when soap is treated with +_cold_ water, it is said to undergo hydrolysis, the reaction taking +place being represented in its simplest form by the equation:-- + + 2NaC_{18}H_{35}O_{2} + H_{2}O = NaOH + HNa(C_{18}H_{35}O_{2})_{2} + sodium water caustic acid sodium + stearate soda stearate + +The actual reaction which occurs has been the subject of investigation +by many chemists, and very diverse conclusions have been arrived at. +Chevreul, the pioneer in the modern chemistry of oils and fats, found +that a small amount of alkali was liberated, as appears in the above +equation, together with the formation of an acid salt, a very minute +quantity of free fatty acid remaining in solution. Rotondi (_Journ. Soc. +Chem. Ind._, 1885, 601), on the other hand, considered that a neutral +soap, on being dissolved in water, was resolved into a basic and an acid +salt, the former readily soluble in both hot and cold water, the latter +insoluble in cold water, and only slightly soluble in hot water. He +appears, however, to have been misled by the fact that sodium oleate is +readily soluble in cold water, and his views have been shown to be +incorrect by Krafft and Stern (_Ber. d. Chem. Ges._, 1894, 1747 and +1755), who from experiments with pure sodium palmitate and stearate +entirely confirm the conclusions arrived at by Chevreul. + +The extent of dissociation occurring when a soap is dissolved in water +depends upon the nature of the fatty acids from which the soap is made, +and also on the concentration of the solution. The sodium salts of +cocoa-nut fatty acids (capric, caproic and caprylic acids) are by far +the most easily hydrolysed, those of oleic acid and the fatty acids from +cotton-seed oil being dissociated more readily than those of stearic +acid and tallow fatty acids. The decomposition increases with the amount +of water employed. + +The hydrolytic action of water on soap is affected very considerably by +the presence of certain substances dissolved in the water, particularly +salts of calcium and magnesium. Caustic soda exerts a marked retarding +effect on the hydrolysis, as do also ethyl and amyl alcohols and +glycerol. + +_Detergent Action of Soap._--The property possessed by soap of removing +dirt is one which it is difficult to satisfactorily explain. Many +theories, more or less complicated, have been suggested, but even now +the question cannot be regarded as solved. + +The explanation commonly accepted is that the alkali liberated by +hydrolysis attacks any greasy matter on the surface to be cleansed, and, +as the fat is dissolved, the particles of dirt are loosened and easily +washed off. Berzelius held this view, and considered that the value of a +soap depended upon the ease with which it yielded free alkali on +solution in water. + +This theory is considered by Hillyer (_Journ. Amer. Chem. Soc._, 1903, +524), however, to be quite illogical, for, as he points out, the +liberated alkali would be far more likely to recombine with the acid or +acid salt from which it has been separated, than to saponify a neutral +glyceride, while, further, unsaponifiable greasy matter is removed by +soap as easily as saponifiable fat, and there can be no question of any +chemical action of the free alkali in its case. Yet another argument +against the theory is that hydrolysis is greater in cold and dilute +solutions, whereas hot concentrated soap solutions are generally +regarded as having the best detergent action. + +Rotondi (_Journ. Soc. Chem. Ind._, 1885, 601) was of the opinion that +the basic soap, which he believed to be formed by hydrolysis, was alone +responsible for the detergent action of soap, this basic soap dissolving +fatty matter by saponification, but, as already pointed out, his theory +of the formation of a basic soap is now known to be incorrect, and his +conclusions are therefore invalid. + +Several explanations have been suggested, based on the purely physical +properties of soap solutions. Most of these are probably, at any rate in +part, correct, and there can be little doubt that the ultimate solution +of the problem lies in this direction, and that the detergent action of +soap will be found to depend on many of these properties, together with +other factors not yet known. + +Jevons in 1878 in some researches on the "Brownian movement" or +"pedesis" of small particles, a movement of the particles which is +observed to take place when clay, iron oxide, or other finely divided +insoluble matter is suspended in water, found that the pedetic action +was considerably increased by soap and sodium silicate, and suggested +that to this action of soap might be attributed much of its cleansing +power. + +Alder Wright considered that the alkali liberated by hydrolysis in some +way promoted contact of the water with the substance to be cleansed, and +Knapp regarded the property of soap solutions themselves to facilitate +contact of the water with the dirt, as one of the chief causes of the +efficacy of soap as a detergent. + +Another way in which it has been suggested that soap acts as a cleanser +is that the soap itself or the alkali set free by hydrolysis serves as a +lubricant, making the dirt less adherent, and thus promoting its +removal. + +The most likely theory yet advanced is that based on the emulsifying +power of soap solutions. The fact that these will readily form emulsions +with oils has long been known, and the detergent action of soap has +frequently been attributed to it, the explanation given being that the +alkali set free by the water emulsifies the fatty matter always adhering +to dirt, and carries it away in suspension with the other impurities. +Experiments by Hillyer (_loc. cit._) show, however, that while N/10 +solution of alkali will readily emulsify a cotton-seed oil containing +free acidity, no emulsion is produced with an oil from which all the +acidity has been removed, or with kerosene, whereas a N/10 solution of +sodium oleate will readily give an emulsion with either, thus proving +that the emulsification is due to the soap itself, and not to the +alkali. + +Plateau (_Pogg. Ann._, 141, 44) and Quincke (_Wiedmann's. Ann._, 35, +592) have made very complete researches on the emulsification and +foaming of liquids and on the formation of bubbles. The former considers +that there are two properties of a liquid which play an important part +in the phenomenon, (1) it must have considerable viscosity, and (2) its +surface tension must be low. Quincke holds similar views, but considers +that no pure liquid will foam. + +Soap solution admirably fulfils Plateau's second condition, its surface +tension being only about 40 per cent. of that of water, while its +cohesion is also very small; and it is doubtless to this property that +its emulsifying power is chiefly due. So far as viscosity is concerned, +this can have but little influence, for a 1 per cent. solution of sodium +oleate, which has a viscosity very little different from that of pure +water, is an excellent emulsifying agent. + +Hillyer, to whose work reference has already been made, investigated the +whole question of detergent action very exhaustively, and, as the result +of a very large number of experiments, concludes that the cleansing +power of soap is largely or entirely to be explained by the power which +it has of emulsifying oily substances, of wetting and penetrating into +oily textures, and of lubricating texture and impurities so that these +may be removed easily. It is thought that all these properties may be +explained by taking into account the low cohesion of the soap solutions, +and their strong attraction or affinity to oily matter, which together +cause the low surface tension between soap solution and oil. + + + + +CHAPTER II. + +CONSTITUTION OF OILS AND FATS, AND THEIR SAPONIFICATION. + + _Researches of Chevreul and Berthelot--Mixed Glycerides--Modern + Theories of Saponification--Hydrolysis accelerated by (1) Heat + or Electricity, (2) Ferments; Castor-seed Ferment, Steapsin, + Emulsin, and (3) Chemical Reagents; Sulphuric Acid, Twitchell's + Reagent, Hydrochloric Acid, Lime, Magnesia, Zinc Oxide, Soda + and Potash._ + + +The term oil is of very wide significance, being applied to substances +of vastly different natures, both organic and inorganic, but so far as +soap-making materials are concerned, it may be restricted almost +entirely to the products derived from animal and vegetable sources, +though many attempts have been made during the last few years to also +utilise mineral oils for the preparation of soap. Fats readily become +oils on heating beyond their melting points, and may be regarded as +frozen oils. + +Although Scheele in 1779 discovered that in the preparation of lead +plaster glycerol is liberated, soap at that time was regarded as a mere +mechanical mixture, and the constitution of oils and fats was not +properly understood. It was Chevreul who showed that the manufacture of +soap involved a definite chemical decomposition of the oil or fat into +fatty acid and glycerol, the fatty acid combining with soda, potash, or +other base, to form the soap, and the glycerol remaining free. The +reactions with stearin and palmitin (of which tallow chiefly consists) +and with olein (found largely in olive and cotton-seed oils) are as +follows:-- + + CH_{2}OOC_{18}H_{35} CH_{2}OH + | | + CHOOC_{18}H_{35} + 3NaOH = 3NaOOC_{18}H_{35} + CHOH + | | + CH_{2}OOC_{18}H_{35} CH_{2}OH + + stearin sodium sodium glycerol + hydroxide stearate + + + CH_{2}OOC_{16}H_{31} CH_{2}OH + | | + CHOOC_{16}H_{31} + 3NaOH = 3NaOOC_{16}H_{31} + CHOH + | | + CH_{2}OOC_{16}H_{31} CH_{2}OH + + palmitin sodium sodium glycerol + hydroxide palmitate + + CH_{2}OOC_{18}H_{33} CH_{2}OH + | | + CHOOC_{18}H_{33} + 3NaOH = 3NaOOC_{18}H_{33} + CHOH + | | + CH_{2}OOC_{18}H_{33} CH_{2}OH + + olein sodium sodium glycerol + hydroxide oleate + +Berthelot subsequently confirmed Chevreul's investigations by directly +synthesising the fats from fatty acids and glycerol, the method he +adopted consisting in heating the fatty acids with glycerol in sealed +tubes. Thus, for example:-- + + 3C_{18}H_{35}O_{2}H + C_{3}H_{5}(OH)_{3} = C_{3}H_{5}(C_{18}H_{35}O_{2})_{3} + stearic acid glycerol tristearin + +Since glycerol is a trihydric alcohol, _i.e._, contains three hydroxyl +(OH) groups, the hydrogen atoms of which are displaceable by acid +radicles, the above reaction may be supposed to take place in three +stages. Thus, we may have:-- + + (1) C_{18}H_{35}O_{2}H + C_{3}H_{5}(OH)_{3} = + C_{3}H_{5}(OH)_{2}C_{18}H_{35}O_{2} + H_{2}O + monostearin + + (2) C_{18}H_{35}O_{2}H + C_{3}H_{5}(OH)_{2}C_{18}H_{35}O_{2} = + C_{3}H_{5}(OH)(C_{18}H_{35}O_{2})_{2} + H_{2}O + distearin + + (3) C_{18}H_{35}O_{2}H + C_{3}H_{5}(OH)(C_{18}H_{35}O_{2})_{2} = + C_{3}H_{5}(C_{18}H_{35}O_{2})_{3} + H_{2}O + tristearin + +There are two possible forms of monoglyceride and diglyceride, according +to the relative position of the acid radicle, these being termed alpha +and beta respectively, and represented by the following formulæ, where R +denotes the acid radicle:-- + +_Monoglyceride_:-- + + CH_{2}OR CH_{2}OH + | | + (alpha) CHOH and (beta) CHOR + | | + CH_{2}OH CH_{2}OH + +_Diglyceride_:-- + + CH_{2}OR CH_{2}OR + | | + (alpha) CHOH and (beta) CHOR + | | + CH_{2}OR CH_{2}OH + +According to the relative proportions of fatty acid and glycerol used, +and the temperature to which they were heated, Berthelot succeeded in +preparing mono-, di- and triglycerides of various fatty acids. + +Practically all the oils and fats used in soap-making consist of +mixtures of these compounds of glycerol with fatty acids, which +invariably occur in nature in the form of triglycerides. + +It was formerly considered that the three acid radicles in any naturally +occurring glyceride were identical, corresponding to the formula-- + + CH_{2}OR + | + CHOR + | + CH_{2}OR + +where R denotes the acid radicle. Recent work, however, has shown the +existence of several so-called _mixed glycerides_, in which the +hydroxyls of the same molecule of glycerol are displaced by two or +sometimes three different acid radicles. + +The first mixed glyceride to be discovered was oleodistearin, +C_{3}H_{5}(OC_{18}H_{35}O)(OC_{18}H_{35}O)_{2}, obtained by Heise in 1896 +Mkani fat. Hansen has since found that tallow contains oleodipalmitin, +from C_{3}H_{5}(OC_{18}H_{35}O)(OC_{16}H_{31}O), stearodipalmitin, +C_{3}H_{5}(OC_{18}H_{35}O)(OC_{16}H_{31}O), oleopalmitostearin, +C_{3}H_{5}(OC_{18}H_{33}O)(OC_{16}H_{31}O)(OC_{18}H_{35}O) and +palmitodistearin, CH(OC_{16}H_{31}O)(OC_{18}H_{35}O)_{2}, the latter of +which has also been obtained by Kreis and Hafner from lard, while Holde +and Stange have shown that olive oil contains from 1 to 2 per cent. of +oleodidaturin, C_{3}H_{5}(OC_{18}H_{33}O)(OC_{17}H_{33}O)_{2}, and +Hehner and Mitchell have obtained indications of mixed glycerides in +linseed oil (which they consider contains a compound of glycerol with +two radicles of linolenic acid and one radicle of oleic acid), also in +cod-liver, cod, whale and shark oils. + +In some cases the fatty acids are combined with other bases than +glycerol. As examples may be cited beeswax, containing myricin or +myricyl palmitate, and spermaceti, consisting chiefly of cetin or cetyl +palmitate, and herein lies the essential difference between fats and +waxes, but as these substances are not soap-making materials, though +sometimes admixed with soap to accomplish some special object, they do +not require further consideration. + +The principal pure triglycerides, with their formulæ and chief +constants, are given in the following table:-- + +[Transcriber's note: Table split to fit on page better.] + +--------------------------------------------------------------------- +Glyceride. | Formula. | Chief Occurrence. +--------------------------------------------------------------------- +Butyrin | C_{3}H_{5}(O.C_{4}H_{7}O)_{3} | Butter fat +--------------------------------------------------------------------- +Isovalerin | C_{3}H_{5}(O.C_{5}H_{9}O)_{3} | Porpoise, dolphin +--------------------------------------------------------------------- +Caproin | C_{3}H_{5}(O.C_{6}H_{11}O)_{3} | Cocoa-nut and + | | palm-nut oils +--------------------------------------------------------------------- +Caprylin | C_{3}H_{5}(O.C_{8}H_{15}O)_{3} | Do. do. +--------------------------------------------------------------------- +Caprin | C_{3}H_{5}(O.C_{10}H_{19}O)_{3} | Do. do. +--------------------------------------------------------------------- +Laurin | C_{3}H_{5}(O.C_{12}H_{23}O)_{3} | Do. do. +--------------------------------------------------------------------- +Myristin | C_{3}H_{5}(O.C_{14}H_{27}O)_{3} | Nutmeg butter +--------------------------------------------------------------------- +Palmitin | C_{3}H_{5}(O.C_{16}H_{31}O)_{3} | Palm oil, lard +--------------------------------------------------------------------- +Stearin | C_{3}H_{5}(O.C_{18}H_{35}O)_{3} | Tallow, lard, + | | cacao butter +--------------------------------------------------------------------- +Olein | C_{3}H_{5}(O.C_{18}H_{33}O)_{3} | Olive and + | | almond oils +--------------------------------------------------------------------- +Ricinolein | C_{3}H_{5}(O.C_{18}H_{33}O_{2})_{3} | Castor oil +--------------------------------------------------------------------- + +--------------------------------------------------------------------- +Glyceride. | Melting | Refractive | Saponification + | Point, °C. | Index at 60° C. | Equivalent. +--------------------------------------------------------------------- +Butyrin | Liquid at -60 | 1.42015 | 100.7 +--------------------------------------------------------------------- +Isovalerin | ... | ... | 114.7 +--------------------------------------------------------------------- +Caproin | -25 | 1.42715 | 128.7 +--------------------------------------------------------------------- +Caprylin | -8.3 | 1.43316 | 156.7 +--------------------------------------------------------------------- +Caprin | 31.1 | 1.43697 | 184.7 +--------------------------------------------------------------------- +Laurin | 45 | 1.44039 | 212.7 +--------------------------------------------------------------------- +Myristin | 56.5 | 1.44285 | 240.7 +--------------------------------------------------------------------- +Palmitin | 63-64 | ... | 268.7 +--------------------------------------------------------------------- +Stearin | 71.6 | ... | 296.7 +--------------------------------------------------------------------- +Olein | Solidifies at -6 | ... | 294.7 +--------------------------------------------------------------------- +Ricinolein | ... | ... | 310.7 +--------------------------------------------------------------------- + +Of the above the most important from a soap-maker's point of view are +stearin, palmitin, olein and laurin, as these predominate in the fats +and oils generally used in that industry. The presence of stearin and +palmitin, which are solid at the ordinary temperature, gives firmness to +a fat; the greater the percentage present, the harder the fat and the +higher will be the melting point, hence tallows and palm oils are solid, +firm fats. Where olein, which is liquid, is the chief constituent, we +have softer fats, such as lard, and liquid oils, as almond, olive and +cotton-seed. + +_Stearin_ (Tristearin) can be prepared from tallow by crystallisation +from a solution in ether, forming small crystals which have a bright +pearly lustre. The melting point of stearin appears to undergo changes +and suggests the existence of distinct modifications. When heated to 55° +C. stearin liquefies; with increase of temperature it becomes solid, and +again becomes liquid at 71.6° C. If this liquid be further heated to 76° +C., and allowed to cool, it will not solidify until 55° C. is reached, +but if the liquid at 71.6° C. be allowed to cool, solidification will +occur at 70° C. + +_Palmitin_ (Tripalmitin) may be obtained by heating together palmitic +acid and glycerol, repeatedly boiling the resulting product with strong +alcohol, and allowing it to crystallise. Palmitin exists in scales, +which have a peculiar pearly appearance, and are greasy to the touch. +After melting and solidifying, palmitin shows no crystalline fracture; +when heated to 46° C. it melts to a liquid which becomes solid on +further heating, again liquefying when 61.7° C. is reached, and becoming +cloudy, with separation of crystalline particles. At 63° C. it is quite +clear, and this temperature is taken as the true melting point. It has +been suggested that the different changes at the temperatures mentioned +are due to varying manipulation, such as rate at which the temperature +is raised, and the initial temperature of the mass when previously cool. + +_Olein_ (Triolein) is an odourless, colourless, tasteless oil, which +rapidly absorbs oxygen and becomes rancid. It has been prepared +synthetically by heating glycerol and oleic acid together, and may be +obtained by submitting olive oil to a low temperature for several days, +when the liquid portion may be further deprived of any traces of stearin +and palmitin by dissolving in alcohol. Olein may be distilled _in vacuo_ +without decomposition taking place. + +_Laurin_ (Trilaurin) may be prepared synthetically from glycerol and +lauric acid. It crystallises in needles, melting at 45°-46° C., which +are readily soluble in ether, but only slightly so in cold absolute +alcohol. Scheij gives its specific gravity, _d_60°/4° = 0.8944. Laurin +is the chief constituent of palm-kernel oil, and also one of the +principal components of cocoa-nut oil. + +_Fatty Acids._--When a fat or oil is saponified with soda or potash, the +resulting soap dissolved in hot water, and sufficient dilute sulphuric +acid added to decompose the soap, an oily layer gradually rises to the +surface of the liquid, which, after clarifying by warming and washing +free from mineral acid, is soluble in alcohol and reddens blue litmus +paper. This oily layer consists of the "fatty acids" or rather those +insoluble in water, acids like acetic, propionic, butyric, caproic, +caprylic and capric, which are all more or less readily soluble in +water, remaining for the most part dissolved in the aqueous portion. All +the acids naturally present in oils and fats, whether free or combined, +are monobasic in character, that is to say, contain only one +carboxyl--CO.OH group. The more important fatty acids may be classified +according to their chemical constitution into five homologous series, +having the general formulæ:-- + + I. Stearic series C_{n}H_{2n+1}COOH + II. Oleic series C_{n}H_{2n-1}COOH + III. Linolic series C_{n}H_{2n-3}COOH + IV. Linolenic series C_{n}H_{2n-5}COOH + V. Ricinoleic series C_{n}H_{2n-7}COOH + +I. _Stearic Series._--The principal acids of this series, together with +their melting points and chief sources, are given in the following +table:-- + +------------------------------------------------------------------------------- +Acid. | Formula. | Melting | Found in + | | Point, | + | | °C. | +------------------------------------------------------------------------------- +Acetic | CH_{3}COOH | 17 | Macassar oil. +------------------------------------------------------------------------------ +Butyric | C_{3}H_{7}COOH | ... | Butter, Macassar oil. +------------------------------------------------------------------------------ +Isovaleric | C_{4}H_{9}COOH | ... | Porpoise and dolphin oils. +------------------------------------------------------------------------------ +Caproic | C_{5}H_{11}COOH | ... | Butter, cocoa-nut oil. +------------------------------------------------------------------------------ +Caprylic | C_{7}H_{15}COOH | 15 | Butter, cocoa-nut oil, + | | | Limburg cheese. +------------------------------------------------------------------------------ +Capric | C_{9}H_{19}COOH | 30 | Butter, cocoa-nut oil. +------------------------------------------------------------------------------ +Lauric | C_{11}H_{23}COOH | 44 | Cocoa-nut oil, palm-kernel oil. +------------------------------------------------------------------------------ +Ficocerylic | C_{12}H_{25}COOH | ... | Pisang wax. +------------------------------------------------------------------------------ +Myristic | C_{13}H_{27}COOH | 54 | Nutmeg butter, liver fat, + | | | cocoa-nut oil, dika fat, + | | | croton oil. +------------------------------------------------------------------------------ +Palmitic | C_{15}H_{31}COOH | 62.5 | Palm oil, most animal fats. +------------------------------------------------------------------------------ +Daturic | C_{16}H_{33}COOH | | Oil of Datura Stramonium. +------------------------------------------------------------------------------ +Stearic | C_{17}H_{35}COOH | 69 | Tallow, lard, most solid + | | | animal fats. +------------------------------------------------------------------------------ +Arachidic | C_{19}H_{39}COOH | 75 | Arachis or earth-nut oil, + | | | rape and mustard-seed oils. +------------------------------------------------------------------------------ +Behenic | C_{21}H_{43}COOH | ... | Ben oil, black mustard-seed + | | | oil, rape oil. +------------------------------------------------------------------------------ +Lignoceric | C_{23}H_{47}COOH | 80.5 | Arachis oil. +------------------------------------------------------------------------------ +Carnaubic | C_{23}H_{47}COOH | ... | Carnauba wax. +------------------------------------------------------------------------------ +Pisangcerylic | C_{23}H_{47}COOH | ... | Pisang wax. +------------------------------------------------------------------------------ +Hyænic | C_{24}H_{49}COOH | ... | Hyæna fat. +------------------------------------------------------------------------------ +Cerotic | C_{25}H_{51}COOH | 78 | Beeswax, China wax, spermaceti. +------------------------------------------------------------------------------ +Melissic | C_{29}H_{59}COOH | 89 | Beeswax. +------------------------------------------------------------------------------ +Psyllostearylic| C_{32}H_{65}COOH | ... | Psylla wax. +------------------------------------------------------------------------------ +Theobromic | C_{63}H_{127}COOH | ... | Cacao butter +------------------------------------------------------------------------------ + +Medullic and margaric acids, which were formerly included in this +series, have now been shown to consist of mixtures of stearic and +palmitic, and stearic palmitic and oleic acids respectively. + +The acids of this group are saturated compounds, and will not combine +directly with iodine or bromine. The two first are liquid at ordinary +temperatures, distil without decomposition, and are miscible with water +in all proportions; the next four are more or less soluble in water and +distil unchanged in the presence of water, as does also lauric acid, +which is almost insoluble in cold water, and only slightly dissolved by +boiling water. The higher acids of the series are solid, and are +completely insoluble in water. All these acids are soluble in warm +alcohol, and on being heated with solid caustic alkali undergo no +change. + +II. _Oleic Series:_-- + +-------------------------------------------------------------------------- +Acid. | Formula. | Melting | Found in + | | Point, | + | | °C. | +-------------------------------------------------------------------------- +Tiglic | C_{4}H_{7}COOH | 64.5 | Croton oil. +-------------------------------------------------------------------------- +Moringic | C_{14}H_{27}COOH | 0 | Ben oil. +-------------------------------------------------------------------------- +Physetoleic | C_{15}H_{29}COOH | 30 | Sperm oil. +-------------------------------------------------------------------------- +Hypogæic | C_{15}H_{29}COOH | 33 | Arachis and maize oils. +-------------------------------------------------------------------------- +Oleic | C_{17}H_{33}COOH | 14 | Most oils and fats. +-------------------------------------------------------------------------- +Rapic | C_{17}H_{33}COOH | ... | Rape oil. +-------------------------------------------------------------------------- +Doeglic | C_{18}H_{35}COOH | ... | Bottle-nose oil. +-------------------------------------------------------------------------- +Erucic | C_{21}H_{41}COOH | 34 | Mustard oils, marine animal + | | | oils, rape oil. +-------------------------------------------------------------------------- + +The unsaturated nature of these acids renders their behaviour with +various reagents entirely different from that of the preceding series. +Thus, they readily combine with bromine or iodine to form addition +compounds, and the lower members of the series are at once reduced, on +treatment with sodium amalgam in alkaline solution, to the corresponding +saturated acids of Series I. Unfortunately, this reaction does not apply +to the higher acids such as oleic acid, but as the conversion of the +latter into solid acids is a matter of some technical importance from +the point of view of the candle-maker, a number of attempts have been +made to effect this by other methods. + +De Wilde and Reychler have shown that by heating oleic acid with 1 per +cent. of iodine in autoclaves up to 270°-280° C., about 70 per cent. is +converted into stearic acid, and Zürer has devised (German Patent +62,407) a process whereby the oleic acid is first converted by the +action of chlorine into the dichloride, which is then reduced with +nascent hydrogen. More recently Norman has secured a patent (English +Patent 1,515, 1903) for the conversion of unsaturated fatty acids of +Series II. into the saturated compounds of Series I., by reduction with +hydrogen or water-gas in the presence of finely divided nickel, cobalt +or iron. It is claimed that by this method oleic acid is completely +transformed into stearic acid, and that the melting point of tallow +fatty acids is raised thereby about 12° C. + +Another method which has been proposed is to run the liquid olein over +a series of electrically charged plates, which effects its reduction to +stearin. + +Stearic acid is also formed by treating oleic acid with fuming hydriodic +acid in the presence of phosphorus, while other solid acids are obtained +by the action of sulphuric acid or zinc chloride on oleic acid. + +Acids of Series II. may also be converted into saturated acids by +heating to 300°C. with solid caustic potash, which decomposes them into +acids of the stearic series with liberation of hydrogen. This reaction, +with oleic acid, for example, is generally represented by the equation-- + + C_{18}H_{34}O_{2} + 2KOH = KC_{2}H_{3}O_{2} + KC_{16}H_{31}O_{2} + H_{2}, + +though it must be really more complex than this indicates, for, as Edmed +has pointed out, oxalic acid is also formed in considerable quantity. +The process on a commercial scale has now been abandoned. + +One of the most important properties of this group of acids is the +formation of isomeric acids of higher melting point on treatment with +nitrous acid, generally termed the _elaidin reaction_. Oleic acid, for +example, acted upon by nitrous acid, yields elaidic acid, melting at +45°, and erucic acid gives brassic acid, melting at 60°C. This reaction +also occurs with the neutral glycerides of these acids, olein being +converted into elaidin, which melts at 32°C. + +The lead salts of the acids of this series are much more soluble in +ether, and the lithium salts more soluble in alcohol than those of the +stearic series, upon both of which properties processes have been based +for the separation of the solid from the liquid fatty acids. + +III. _Linolic Series:_-- + +-------------------------------------------------------------------------- +Acid. | Formula. | Melting | Found in + | | Point, | + | | °C. | +-------------------------------------------------------------------------- +Elæomargaric | C_{16}H_{29}COOH | ... | Chinese-wood oil. +-------------------------------------------------------------------------- +Elæostearic | C_{16}H_{29}COOH | 71 | Chinese-wood oil. +-------------------------------------------------------------------------- +Linolic | C_{17}H_{31}COOH | Fluid | Linseed, cotton-seed and + | | | maize oils. +-------------------------------------------------------------------------- +Tariric | C_{17}H_{31}COOH | 50.5 | Tariri-seed oil. +-------------------------------------------------------------------------- +Telfairic | C_{17}H_{31}COOH | Fluid | Telfairia oil. +-------------------------------------------------------------------------- + +These acids readily combine with bromine, iodine, or oxygen. They are +unaffected by nitrous acid, and their lead salts are soluble in ether. + +IV. _Linolenic Series:_-- + +-------------------------------------------------------------------- +Acid. | Formula. | Found in +-------------------------------------------------------------------- +Linolenic | C_{17}H_{29}COOH | Linseed oil. +-------------------------------------------------------------------- +Isolinolenic | C_{17}H_{29}COOH | Linseed oil. +-------------------------------------------------------------------- +Jecoric | C_{17}H_{29}COOH | Cod-liver and marine animal oils. +-------------------------------------------------------------------- + +These acids are similar in properties to those of Class III., but +combine with six atoms of bromine or iodine, whereas the latter combine +with only four atoms. + +V. _Ricinoleic Series:_-- + + ----------------------------------------------------------- +| | | | | +| Acid. | Formula. | Melting | Found in | +| | | Point, | | +| | | °C. | | +|------------|----------------------|---------|-------------| +| | | | | +| Ricinoleic | C_{17}H_{22}(OH)COOH | 4-5 | Castor oil. | + ----------------------------------------------------------- + +This acid combines with two atoms of bromine or iodine, and is converted +by nitrous acid into the isomeric ricinelaidic acid, which melts at +52°-53° C. Pure ricinoleic acid, obtained from castor oil, is optically +active, its rotation being [alpha]_{d} +6° 25'. + +_Hydrolysis or Saponification of Oils and Fats._--The decomposition of a +triglyceride, brought about by caustic alkalies in the formation of +soap, though generally represented by the equation already given (pp. 6 +and 7)-- + + C_{3}H_{5}(OR) + 3NaOH = C_{3}H_{5}(OH)_{3} + 3RONa, + +is not by any means such a simple reaction. + +In the first place, though in this equation no water appears, the +presence of the latter is found to be indispensable for saponification +to take place; in fact, the water must be regarded as actually +decomposing the oil or fat, caustic soda or potash merely acting as a +catalytic agent. Further, since in the glycerides there are three acid +radicles to be separated from glycerol, their saponification can be +supposed to take place in three successive stages, which are the +converse of the formation of mono- and diglycerides in the synthesis of +triglycerides from fatty acids and glycerine. Thus, the above equation +may be regarded as a summary of the following three:-- + + _ _ + | OR | OH + (i.) C_{3}H_{5} | OR + NaOH = C_{3}H_{5} | OR + RONa + |_OR |_OR + _ _ + | OH | OH + (ii.) C_{3}H_{5} | OR + NaOH = C_{3}H_{5} | OR + RONa + |_OR |_OH + _ _ + | OH | OH + (iii.) C_{3}H_{5} | OR + NaOH = C_{3}H_{5} | OH + RONa + |_OH |_OH + +Geitel and Lewkowitsch, who have studied this question from the physical +and chemical point of view respectively, are of opinion that when an +oil or fat is saponified, these three reactions do actually occur side +by side, the soap-pan containing at the same time unsaponified +triglyceride, diglyceride, monoglyceride, glycerol and soap. + +This theory is not accepted, however, by all investigators. Balbiano and +Marcusson doubt the validity of Lewkowitsch's conclusions, and Fanto, +experimenting on the saponification of olive oil with caustic potash, is +unable to detect the intermediate formation of any mono- or diglyceride, +and concludes that in homogeneous solution the saponification is +practically quadrimolecular. Kreeman, on the other hand, from +physico-chemical data, supports the view of Geitel and Lewkowitsch that +saponification is bimolecular, and though the evidence seems to favour +this theory, the matter cannot be regarded as yet definitely settled. + +Hydrolysis can be brought about by water alone, if sufficient time is +allowed, but as the process is extremely slow, it is customary in +practice to accelerate the reaction by the use of various methods, which +include (i.) the application of heat or electricity, (ii.) action of +enzymes, and (iii.) treatment with chemicals; the accelerating effect of +the two latter methods is due to their emulsifying power. + +The most usual method adopted in the manufacture of soap is to hydrolyse +the fat or oil by caustic soda or potash, the fatty acids liberated at +the same time combining with the catalyst, _i.e._, soda or potash, to +form soap. Hitherto the other processes of hydrolysis have been employed +chiefly for the preparation of material for candles, for which purpose +complete separation of the glycerol in the first hydrolysis is not +essential, since the fatty matter is usually subjected to a second +treatment with sulphuric acid to increase the proportion of solid fatty +acids. The colour of the resulting fatty acids is also of no importance, +as they are always subjected to distillation. + +During the last few years, however, there has been a growing attempt to +first separate the glycerol from the fatty acids, and then convert the +latter into soap by treatment with the carbonates of soda or potash, +which are of course considerably cheaper than the caustic alkalies, but +cannot be used in the actual saponification of a neutral fat. The two +processes chiefly used for this purpose are those in which the reaction +is brought about by enzymes or by Twitchell's reagent. + +I. _Application of Heat or Electricity._--Up to temperatures of 150° C. +the effect of water on oils and fats is very slight, but by passing +superheated steam through fatty matter heated to 200°-300° C. the +neutral glycerides are completely decomposed into glycerol and fatty +acids according to the equation-- + + C_{3}H_{5}(OR)_{3} + 3H.OH = C_{3}H_{5}(OH)_{3} + 3ROH. + +The fatty acids and glycerol formed distil over with the excess of +steam, and by arranging a series of condensers, the former, which +condense first, are obtained almost alone in the earlier ones, and an +aqueous solution of glycerine in the later ones. This method of +preparation of fatty acids is extensively used in France for the +production of stearine for candle-manufacture, but the resulting +product is liable to be dark coloured, and to yield a dark soap. To +expose the acids to heat for a minimum of time, and so prevent +discoloration, Mannig has patented (Germ. Pat. 160,111) a process +whereby steam under a pressure of 8 to 10 atmospheres is projected +against a baffle plate mounted in a closed vessel, where it mixes with +the fat or oil in the form of a spray, the rate of hydrolysis being +thereby, it is claimed, much increased. + +Simpson (Fr. Pat. 364,587) has attempted to accelerate further the +decomposition by subjecting oils or fats to the simultaneous action of +heat and electricity. Superheated steam is passed into the oil, in which +are immersed the two electrodes connected with a dynamo or battery, the +temperature not being allowed to exceed 270° C. + +II. _Action of Enzymes._--It was discovered by Muntz in 1871 (_Annales +de Chemie_, xxii.) that during germination of castor seeds a quantity of +fatty acid was developed in the seeds, which he suggested might be due +to the decomposition of the oil by the embryo acting as a ferment. +Schutzenberger in 1876 showed that when castor seeds are steeped in +water, fatty acids and glycerol are liberated, and attributed this to +the hydrolytic action of an enzyme present in the seeds. No evidence of +the existence of such a ferment was adduced, however, till 1890, when +Green (_Roy. Soc. Proc._, 48, 370) definitely proved the presence in the +seeds of a ferment capable of splitting up the oil into fatty acid and +glycerol. + +The first experimenters to suggest any industrial application of this +enzymic hydrolysis were Connstein, Hoyer and Wartenburg, who +(_Berichte_, 1902, 35, pp. 3988-4006) published the results of a lengthy +investigation of the whole subject. They found that tallow, cotton-seed, +palm, olive, almond, and many other oils, were readily hydrolysed by the +castor-seed ferment in the presence of dilute acid, but that cocoa-nut +and palm-kernel oils only decomposed with difficulty. The presence of +acidity is essential for the hydrolysis to take place, the most suitable +strength being one-tenth normal, and the degree of hydrolysis is +proportional to the quantity of ferment present. Sulphuric, phosphoric, +acetic or butyric acids, or sodium bisulphate, may be used without much +influence on the result. Butyric acid is stated to be the best, but in +practice is too expensive, and acetic acid is usually adopted. The +emulsified mixture should be allowed to stand for twenty-four hours, and +the temperature should not exceed 40° C.; at 50° C. the action is +weakened, and at 100° C. ceases altogether. + +Several investigators have since examined the hydrolysing power of +various other seeds, notably Braun and Behrendt (_Berichte_, 1903, 36, +1142-1145, 1900-1901, and 3003-3005), who, in addition to confirming +Connstein, Hoyer and Wartenburg's work with castor seeds, have made +similar experiments with jequirity seeds (_Abrus peccatorius_) +containing the enzyme abrin, emulsin from crushed almonds, the leaves of +_Arctostaphylos Uva Ursi_, containing the glucoside arbutin, myrosin +from black mustard-seed, gold lac (_Cheirantus cheiri_) and crotin from +croton seeds. Jequirity seeds were found to have a stronger decomposing +action on lanoline and carnauba wax than the castor seed, but only +caused decomposition of castor oil after the initial acidity was first +neutralised with alkali. Neither emulsin, arbutin nor crotin have any +marked hydrolytic action on castor oil, but myrosin is about half as +active as castor seeds, except in the presence of potassium myronate, +when no decomposition occurs. + +S. Fokin (_J. russ. phys. chem. Ges._, 35, 831-835, and _Chem. Rev. +Fett. u. Harz. Ind._, 1904, 30 _et seq._) has examined the hydrolytic +action of a large number of Russian seeds, belonging to some thirty +different families, but although more than half of these brought about +the hydrolysis of over 10 per cent. of fat, he considers that in only +two cases, _viz._, the seeds of _Chelidonium majus_ and _Linaria +vulgaris_, is the action due to enzymes, these being the only two seeds +for which the yield of fatty acids is proportional to the amount of seed +employed, while in many instances hydrolysis was not produced when the +seeds were old. The seeds of _Chelidonium majus_ were found to have as +great, and possibly greater, enzymic activity than castor seeds, but +those of _Linaria_ are much weaker, twenty to thirty parts having only +the same lipolytic activity as four to five parts of castor seeds. + +The high percentage of free acids found in rice oil has led C. A. Brown, +jun. (_Journ. Amer. Chem. Soc._, 1903, 25, 948-954), to examine the rice +bran, which proves to have considerable enzymic activity, and rapidly +effects the hydrolysis of glycerides. + +The process for the utilisation of enzymic hydrolysis in the separation +of fatty acids from glycerine on the industrial scale, as originally +devised by Connstein and his collaborators, consisted in rubbing a +quantity of the coarsely crushed castor seeds with part of the oil or +fat, then adding the rest of the oil, together with acidified water +(N/10 acetic acid). The quantities employed were 6-1/2 parts of +decorticated castor beans for every 100 parts of oil or fat, and 50 to +60 parts of acetic acid. After stirring until an emulsion is formed, the +mixture is allowed to stand for twenty-four hours, during which +hydrolysis takes place. The temperature is then raised to 70°-80° C., +which destroys the enzyme, and a 25 per cent. solution of sulphuric +acid, equal in amount to one-fiftieth of the total quantity of fat +originally taken, added to promote separation of the fatty acids. In +this way three layers are formed, the one at the top consisting of the +clear fatty acids, the middle one an emulsion containing portions of the +seeds, fatty acids and glycerine, and the bottom one consisting of the +aqueous glycerine. The intermediate layer is difficult to treat +satisfactorily; it is generally washed twice with water, the washings +being added to glycerine water, and the fatty mixture saponified and the +resultant soap utilised. + +The process has been the subject of a considerable amount of +investigation, numerous attempts having been made to actually separate +the active fat-splitting constituent of the seeds, or to obtain it in a +purer and more concentrated form than is furnished by the seeds +themselves. Nicloux (_Comptes Rendus_, 1904, 1112, and _Roy. Soc. +Proc._, 1906, 77 B, 454) has shown that the hydrolytic activity of +castor seeds is due entirely to the cytoplasm, which it is possible to +separate by mechanical means from the aleurone grains and all other +cellular matter. This active substance, which he terms "lipaseidine," is +considered to be not an enzyme, though it acts as such, following the +ordinary laws of enzyme action; its activity is destroyed by contact +with water in the absence of oil. This observer has patented (Eng. Pat. +8,304, 1904) the preparation of an "extract" by triturating crushed +castor or other seeds with castor oil, filtering the oily extract, and +subjecting it to centrifugal force. The deposit consists of aleurone and +the active enzymic substance, together with about 80 per cent. of oil, +and one part of it will effect nearly complete hydrolysis of 100 parts +of oil in twenty-four hours. In a subsequent addition to this patent, +the active agent is separated from the aleurone by extraction with +benzene and centrifugal force. By the use of such an extract, the +quantity of albuminoids brought into contact with the fat is reduced to +about 10 per cent. of that in the original seeds, and the middle layer +between the glycerine solution and fatty acids is smaller and can be +saponified directly for the production of curd soap, while the glycerine +solution also is purer. + +In a further patent Nicloux (Fr. Pat. 349,213, 1904) states that the use +of an acid medium is unnecessary, and claims that even better results +are obtained by employing a neutral solution of calcium sulphate +containing a small amount of magnesium sulphate, the proportion of salts +not exceeding 0.5 per cent. of the fat, while in yet another patent, +jointly with Urbain (Fr. Pat. 349,942, 1904), it is claimed that the +process is accelerated by the removal of acids from the oil or fat to be +treated, which may be accomplished by either washing first with +acidulated water, then with pure water, or preferably by neutralising +with carbonate of soda and removing the resulting soap. + +Lombard (Fr. Pat. 350,179, 1904) claims that acids act as stimulating +agents in the enzymic hydrolysis of oils, and further that a simple +method of obtaining the active product is to triturate oil cake with its +own weight of water, allow the mixture to undergo spontaneous +proteolytic hydrolysis at 40° C. for eight days, and then filter, the +filtrate obtained being used in place of water in the enzymic process. + +Hoyer, who has made a large number of experiments in the attempt to +isolate the lipolytic substance from castor seeds, has obtained a +product of great activity, which he terms "ferment-oil," by extracting +the crushed seeds with a solvent for oils. + +The Verein Chem. Werke have extended their original patent (addition +dated 11th December, 1905, to Fr. Pat. 328,101, Oct., 1902), which now +covers the use of vegetable ferments in the presence of water and +manganese sulphate or other metallic salt. It is further stated that +acetic acid may be added at the beginning of the operation, or use may +be made of that formed during the process, though in the latter case +hydrolysis is somewhat slower. + +Experiments have been carried out by Lewkowitsch and Macleod (_Journ. +Soc. Chem. Ind._, 1903, 68, and _Proc. Roy. Soc._, 1903, 31) with +ferments derived from animal sources, _viz._, lipase from pig's liver, +and steapsin from the pig or ox pancreas. The former, although it has +been shown by Kastle and Loevenhart (_Amer. Chem. Journ._, 1900, 49) to +readily hydrolyse ethyl butyrate, is found to have very little +fat-splitting power, but with steapsin more favourable results have been +obtained, though the yield of fatty acids in this case is considerably +inferior to that given by castor seeds. With cotton-seed oil, 83-86 per +cent. of fatty acids were liberated as a maximum after fifty-six days, +but with lard only 46 per cent. were produced in the same time. Addition +of dilute acid or alkali appeared to exert no influence on the +decomposition of the cotton-seed oil, but in the case of the lard, +dilute alkali seemed at first to promote hydrolysis, though afterwards +to retard it. + +Fokin (_Chem. Rev. Fett. u. Harz. Ind._, 1904, 118-120 _et seq._) has +attempted to utilise the pancreatic juice on a technical scale, but the +process proved too slow and too costly to have any practical use. + +_Rancidity._--The hydrolysing power of enzymes throws a good deal of +light on the development of rancidity in oils and fats, which is now +generally regarded as due to the oxidation by air in the presence of +light and moisture of the free fatty acids contained by the oil or fat. +It has long been known that whilst recently rendered animal fats are +comparatively free from acidity, freshly prepared vegetable oils +invariably contain small quantities of free fatty acid, and there can be +no doubt that this must be attributed to the action of enzymes contained +in the seeds or fruit from which the oils are expressed, hence the +necessity for separating oils and fats from adhering albuminous matters +as quickly as possible. + +_Decomposition of Fats by Bacteria._--Though this subject is not of any +practical interest in the preparation of fatty acids for soap-making, it +may be mentioned, in passing, that some bacteria readily hydrolyse fats. +Schriber (_Arch. f. Hyg._, 41, 328-347) has shown that in the presence +of air many bacteria promote hydrolysis, under favourable conditions as +to temperature and access of oxygen, the process going beyond the simple +splitting up into fatty acid and glycerol, carbon dioxide and water +being formed. Under anærobic conditions, however, only a slight primary +hydrolysis was found to take place, though according to Rideal (_Journ. +Soc. Chem. Ind._, 1903, 69) there is a distinct increase in the amount +of free fatty acids in a sewage after passage through a septic tank. + +Experiments have also been made on this subject by Rahn (_Centralb. +Bakteriol_, 1905, 422), who finds that _Penicillium glaucum_ and other +penicillia have considerable action on fats, attacking the glycerol and +lower fatty acids, though not oleic acid. A motile bacillus, producing +a green fluorescent colouring matter, but not identified, had a marked +hydrolytic action and decomposed oleic acid. The name "lipobacter" has +been proposed by De Kruyff for bacteria which hydrolyse fats. + +III. _Use of Chemical Reagents._--Among the chief accelerators employed +in the hydrolysis of oils are sulphuric acid and Twitchell's reagent +(benzene- or naphthalene-stearosulphonic acid), while experiments have +also been made with hydrochloric acid (_Journ. Soc. Chem. Ind._, 1903, +67) with fairly satisfactory results, and the use of sulphurous acid, or +an alkaline bisulphite as catalyst, has been patented in Germany. To +this class belong also the bases, lime, magnesia, zinc oxide, ammonia, +soda and potash, though these latter substances differ from the former +in that they subsequently combine with the fatty acids liberated to form +soaps. + +_Sulphuric Acid._--The hydrolysing action of concentrated sulphuric acid +upon oils and fats has been known since the latter part of the +eighteenth century, but was not applied on a practical scale till 1840 +when Gwynne patented a process in which sulphuric acid was used to +liberate the fatty acids, the latter being subsequently purified by +steam distillation. By this method, sulpho-compounds of the glyceride +are first formed, which readily emulsify with water, and, on treatment +with steam, liberate fatty acids, the glycerol remaining partly in the +form of glycero-sulphuric acid. The process has been investigated by +Fremy, Geitel, and more recently by Lewkowitsch (_J. Soc. of Arts_, +"Cantor Lectures," 1904, 795 _et seq._), who has conducted a series of +experiments on the hydrolysis of tallow with 4 per cent. of sulphuric +acid of varying strengths, containing from 58 to 90 per cent. sulphuric +acid, H_{2}SO_{4}. Acid of 60 per cent. or less appears to be +practically useless as a hydrolysing agent, while with 70 per cent. acid +only 47.7 per cent. fatty acids were developed after twenty-two hours' +steaming, and with 80 and 85 per cent. acid, the maximum of 89.9 per +cent. of fatty acids was only reached after fourteen and fifteen hours' +steaming respectively. Using 98 per cent. acid, 93 per cent. of fatty +acids were obtained after nine hours' steaming, and after another seven +hours, only 0.6 per cent. more fatty acids were produced. Further +experiments have shown that dilute sulphuric acid has also scarcely any +action on cotton-seed, whale, and rape oils. + +According to Lant Carpenter, some 75 per cent. of solid fatty acids may +be obtained from tallow by the sulphuric acid process, owing to the +conversion of a considerable quantity of oleic acid into isoleic acid +(_vide_ p. 12), but in the process a considerable proportion of black +pitch is obtained. C. Dreymann has recently patented (Eng. Pat. 10,466, +1904) two processes whereby the production of any large amount of +hydrocarbons is obviated. In the one case, after saponification with +sulphuric acid, the liberated fatty acids are washed with water and +treated with an oxide, carbonate, or other acid-fixing body, _e.g._, +sodium carbonate, prior to distillation. In this way the distillate is +much clearer than by the ordinary process, and is almost odourless, +while the amount of unsaponifiable matter is only about 1.2 per cent. +The second method claimed consists in the conversion of the fatty acids +into their methyl esters by treatment with methyl alcohol and +hydrochloric acid gas, and purification of the esters by steam +distillation, the pure esters being subsequently decomposed with +superheated steam, in an autoclave, with or without the addition of an +oxide, _e.g._, 0.1 per cent. zinc oxide, to facilitate their +decomposition. + +_Twitchell's Reagent._--In Twitchell's process use is made of the +important discovery that aqueous solutions of fatty aromatic sulphuric +acids, such as benzene- or naphthalene-stearosulphonic acid, readily +dissolve fatty bodies, thereby facilitating their dissociation into +fatty acids and glycerol. These compounds are stable at 100° C., and are +prepared by treating a mixture of benzene or naphthalene and oleic acid +with an excess of sulphuric acid, the following reaction taking place:-- + + C_{6}H_{6} + C_{18}H_{34}O_{2} + H_{2}SO_{4} = + C_{6}H_{4}(SO_{3}H)C_{18}H_{35}O + H_{2}O. + +On boiling the resultant product with water two layers separate, the +lower one consisting of a clear aqueous solution of sulphuric acid and +whatever benzene-sulphonic acid has been formed, while the upper layer, +which is a viscous oil, contains the benzene-stearosulphonic acid. This, +after washing first with hydrochloric acid and then rapidly with +petroleum ether, and drying at 100° C. is then ready for use; the +addition of a small quantity of this reagent to a mixture of fat +(previously purified) and water, agitated by boiling with open steam, +effects almost complete separation of the fatty acid from glycerol. + +The process is generally carried out in two wooden vats, covered with +closely fitting lids, furnished with the necessary draw-off cocks, the +first vat containing a lead coil and the other a brass steam coil. + +In the first vat, the fat or oil is prepared by boiling with 1 or 2 per +cent. of sulphuric acid (141° Tw. or 60° B.) for one or two hours and +allowed to rest, preferably overnight; by this treatment the fat is +deprived of any dirt, lime or other impurity present. After withdrawing +the acid liquor, the fat or oil is transferred to the other vat, where +it is mixed with one-fifth of its bulk of water (condensed or +distilled), and open steam applied. As soon as boiling takes place, the +requisite amount of reagent is washed into the vat by the aid of a +little hot water through a glass funnel, and the whole is boiled +continuously for twelve or even twenty-four hours, until the free fatty +acids amount to 85-90 per cent. The amount of reagent used varies with +the grade of material, the smaller the amount consistent with efficient +results, the better the colour of the finished product; with good +material, from 1/2 to 3/4 per cent. is sufficient, but for materials of +lower grade proportionately more up to 2 per cent. is required. The +reaction appears to proceed better with materials containing a fair +quantity of free acidity. + +When the process has proceeded sufficiently far, the boiling is stopped +and free steam allowed to fill the vat to obviate any discoloration of +the fatty acids by contact with the air, whilst the contents of the vat +settle. + +The settled glycerine water, which should amount in bulk to 50 or 60 per +cent. of the fatty matter taken, and have a density of 7-1/2° Tw. (5° +B.), is removed to a receptacle for subsequent neutralisation with milk +of lime, and, after the separation of sludge, is ready for +concentration. + +The fatty acids remaining in the vat are boiled with a small quantity +(0.05 per cent., or 1/10 of the Twitchell reagent requisite) of +commercial barium carbonate, previously mixed with a little water; the +boiling may be prolonged twenty or thirty minutes, and at the end of +that period the contents of the vat are allowed to rest; the water +separated should be neutral to methyl-orange indicator. + +It is claimed that fatty acids so treated are not affected by the air, +and may be stored in wooden packages. + +_Hydrochloric Acid._--Lewkowitsch (_Journ. Soc. Chem. Ind._, 1903, 67) +has carried out a number of experiments on the accelerating influence of +hydrochloric acid upon the hydrolysis of oils and fats, which show that +acid of a specific gravity of 1.16 has a very marked effect on most +oils, cocoa-nut, cotton-seed, whale and rape oils, tallow and lard being +broken up into fatty acid and glycerol to the extent of some 82-96 per +cent. after boiling 100 grams of the oil or fat with 100 c.c. of acid +for twenty-four hours. The maximum amount of hydrolysis was attained +with cocoa-nut oil, probably owing to its large proportion of the +glycerides of volatile fatty acids. Castor oil is abnormal in only +undergoing about 20 per cent. hydrolysis, but this is attributed to the +different constitution of its fatty acids, and the ready formation of +polymerisation products. Experiments were also made as to whether the +addition of other catalytic agents aided the action of the hydrochloric +acid; mercury, copper sulphate, mercury oxide, zinc, zinc dust, +aluminium chloride, nitrobenzene and aniline being tried, in the +proportion of 1 per cent. The experiments were made on neutral lard and +lard containing 5 per cent. of free fatty acids, but in no case was any +appreciable effect produced. + +So far this process has not been adopted on the practical scale, its +chief drawback being the length of time required for saponification. +Undoubtedly the hydrolysis would be greatly facilitated if the oil and +acid could be made to form a satisfactory emulsion, but although saponin +has been tried for the purpose, no means of attaining this object has +yet been devised. + +_Sulphurous Acid or Bisulphite._--The use of these substances has been +patented by Stein, Berge and De Roubaix (Germ. Pat. 61,329), the fat +being heated in contact with the reagent for about nine hours at +175°-180° C. under a pressure of some 18 atmospheres, but the process +does not appear to be of any considerable importance. + +_Lime._--The use of lime for the saponification of oils and fats was +first adopted on the technical scale for the production of candle-making +material, by De Milly in 1831. The insoluble lime soap formed is +decomposed by sulphuric acid, and the fatty acids steam distilled. + +The amount of lime theoretically necessary to hydrolyse a given quantity +of a triglyceride, ignoring for the moment any catalytic influence, can +be readily calculated; thus with stearin the reaction may be represented +by the equation:-- + + CH_{2}OOC_{18}H_{35} CH_{2}OH + | | + 2CHOOC_{18}H_{35} + 3Ca(OH)_{2} = 3Ca(OOC_{18}H_{35})_{2} + 2CHOH + | | + CH_{2}OOC_{18}H_{35} CH_{2}OH + stearin milk of lime calcium stearate glycerol + +In this instance, since the molecular weight of stearin is 890 and that +of milk of lime is 74, it is at once apparent that for every 1,780 parts +of stearin, 222 parts of milk of lime or 168 parts of quick-lime, CaO, +would be required. It is found in practice, however, that an excess of +3-5 per cent. above the theoretical quantity of lime is necessary to +complete the hydrolysis of a fat when carried on in an open vessel at +100°-105° C., but that if the saponification be conducted under pressure +in autoclaves the amount of lime necessary to secure almost perfect +hydrolysis is reduced to 2-3 per cent. on the fat, the treatment of fats +with 3 per cent. of lime under a pressure of 10 atmospheres producing a +yield of 95 per cent. of fatty acids in seven hours. The lower the +pressure in the autoclave, the lighter will be the colour of the +resultant fatty acids. + +_Magnesia._--It has been proposed to substitute magnesia for lime in the +process of saponification under pressure, but comparative experiments +with lime and magnesia, using 3 per cent. of lime and 2.7 per cent. of +magnesia (_Journ. Soc. Chem. Ind._, xii., 163), show that saponification +by means of magnesia is less complete than with lime, and, moreover, the +reaction requires a higher temperature and therefore tends to darken the +product. + +_Zinc Oxide._--The use of zinc oxide as accelerating agent has been +suggested by two or three observers. Poullain and Michaud, in 1882, were +granted a patent for this process, the quantity of zinc oxide +recommended to be added to the oil or fat being 0.2 to 0.5 per cent. +Rost, in 1903, obtained a French patent for the saponification of oils +and fats by steam under pressure in the presence of finely divided +metals or metallic oxides, and specially mentions zinc oxide for the +purpose. + +It has also been proposed to use zinc oxide in conjunction with lime in +the autoclave to obviate to some extent the discoloration of the fatty +acids. + +Other catalytic agents have been recommended from time to time, +including strontianite, lead oxide, caustic baryta, aluminium hydrate, +but none of these is of any practical importance. + +_Soda and Potash._--Unlike the preceding bases, the soaps formed by soda +and potash are soluble in water, and constitute the soap of commerce. +These reagents are always used in sufficient quantity to combine with +the whole of the fatty acids contained in an oil or fat, though +doubtless, by the use of considerably smaller quantities, under +pressure, complete resolution of the fatty matter into fatty acids and +glycerol could be accomplished. They are, by far, the most important +saponifying agents from the point of view of the present work, and their +practical use is fully described in Chapter V. + + + + +CHAPTER III. + +RAW MATERIALS USED IN SOAP-MAKING. + + _Fats and Oils--Waste Fats--Fatty Acids--Less-known Oils and + Fats of Limited Use--Various New Fats and Oils Suggested for + Soap-making--Rosin--Alkali (Caustic and + Carbonated)--Water--Salt--Soap-stock._ + + +_Fats and Oils._--All animal and vegetable oils and fats intended for +soap-making should be as free as possible from unsaponifiable matter, of +a good colour and appearance, and in a sweet, fresh condition. The +unsaponifiable matter naturally present as cholesterol, or phytosterol, +ranges in the various oils and fats from 0.2 to 2.0 per cent. All oils +and fats contain more or less free acidity; but excess of acidity, +though it may be due to the decomposition of the glyceride, and does not +always denote rancidity, is undesirable in soap-making material. +Rancidity of fats and oils is entirely due to oxidation, in addition to +free acid, aldehydes and ketones being formed, and it has been proposed +to estimate rancidity by determining the amount of these latter +produced. It is scarcely necessary to observe how very important it is +that the sampling of fats and oils should be efficiently performed, so +that the sample submitted to the chemist may be a fairly representative +average of the parcel. + +In the following short description of the materials used, we give, under +each heading, figures for typical samples of the qualities most suitable +for soap-making. + +_Tallows._--Most of the imported tallow comes from America, Australia +and New Zealand. South American mutton tallow is usually of good +quality; South American beef tallow is possessed of a deep yellow colour +and rather strong odour, but makes a bright soap of a good body and +texture. North American tallows are, as a general rule, much paler in +colour than those of South America, but do not compare with them in +consistence. Most of the Australasian tallows are of very uniform +quality and much in demand. + +Great Britain produces large quantities of tallow which comes into the +market as town and country tallow, or home melt. Owing to the increasing +demand for edible fat, much of the rough fat is carefully selected, +rendered separately, and the product sold for margarine-making. +Consequently the melted tallow for soap-making is of secondary +importance to the tallow melter. + +The following are typical samples of tallow:-- + + _______________________________________________________________________ +| | | | | +| | | Acidity | | +| | Saponification | (as Oleic | Titre, | +| | Equivalent. | Acid) | °C. | +| | | Per Cent. | | +|_________________________________|________________|___________|________| +| | | | | +| Australian mutton | 285 | 0.85 | 45 | +| Australian mutton | 284.4 | 0.48 | 48.3 | +| Australian beef | 284.2 | 1.68 | 43.9 | +| Australian beef | 283.6 | 0.85 | 42.6 | +| Australian mixed | 285.1 | 3.52 | 44 | +| Australian mixed | 284.6 | 1.89 | 43.5 | +| South American mutton | 284.5 | 1.11 | 47 | +| South American mutton | 285 | 0.90 | 47.4 | +| South American beef | 284.7 | 0.81 | 45 | +| South American beef | 284 | 0.94 | 44 | +| North American mutton | 284.3 | 1.32 | 44 | +| North American mutton | 85 | 2.18 | 43.2 | +| North American beef, fine | 284.5 | 1.97 | 41.5 | +| North American beef, good | 283.8 | 4.30 | 42 | +| North American ordinary | 285.2 | 5.07 | 41.75 | +| North American prime city | 286 | 1.01 | 41.2 | +| Selected English mutton | 283.9 | 1.45 | 47 | +| Selected English beef | 284.2 | 2.40 | 44 | +| Home-rendered or country tallow | 284.6 | 5.1 | 43 | +| Town tallow | 285.3 | 7.4 | 42.5 | +|_________________________________|________________|___________|________| + +Tallow should absorb from 39 to 44 per cent. iodine. + +_Lard._--Lard is largely imported into this country from the United +States of America. The following is a typical sample of American hog's +fat offered for soap-making:-- + + ________________________________________________________ +| | | | | +| Saponification | Acidity | Titre, | Refractive | +| Equivalent. | (as Oleic Acid) | °C. | Index | +| | Per Cent. | | at 60° C. | +|________________|_________________|________|____________| +| | | | | +| 286 | 0.5 | 37.5 | 1.4542 | +|________________|_________________|________|____________| + +Lard should absorb 59 to 63 per cent. iodine. + +_Cocoa-nut Oil._--The best known qualities are Cochin and Ceylon oils, +which are prepared in Cochin (Malabar) or the Philippine Islands and +Ceylon respectively. + +The dried kernels of the cocoa-nut are exported to various ports in +Europe, and the oil obtained comes on the market as Continental Coprah +Oil, with the prefix of the particular country or port where it has been +crushed, _e.g._, Belgian, French and Marseilles Coprah Oil. Coprah is +also imported into England, and the oil expressed from it is termed +English Pressed Coprah. + +The following are typical examples from bulk:-- + + _________________________________________________________________________ +| | | | | | +| | Saponification | Acidity | Titre, | Refractive | +| | Equivalent. | (as Oleic Acid) | °C. | Index | +| | | Per Cent. | | at 25° C. | +|________________|________________|_________________|________|____________| +| | | | | | +| Cochin oil | 215.5 | 1.5 | 23.5 | 1.4540 | +| Cochin oil | 214.3 | 2.6 | 22.1 | 1.4541 | +| Ceylon oil | 214.6 | 5.47 | 23 | 1.4535 | +| Ceylon oil | 216 | 3.95 | 22.75 | 1.4535 | +| Belgian coprah | 214.2 | 1.65 | 23 | 1.4541 | +| Belgian coprah | 215 | 2.60 | 22.1 | 1.4540 | +| French coprah | 214.2 | 6.55 | 23 | 1.4535 | +| French coprah | 214.8 | 7.42 | 22 | 1.4540 | +| Pressed coprah | 215.8 | 7.45 | 22.2 | 1.4542 | +| Pressed coprah | 216 | 9.41 | 22 | 1.4555 | +|________________|________________|_________________|________|____________| + +Cocoa-nut oil should absorb 8.9 to 9.3 per cent. iodine. + +_Palm-nut Oil._--The kernels of the palm-tree fruit are exported from +the west coast of Africa to Europe, and this oil obtained from them. +Typical samples of English and Hamburg oils tested:-- + + _________________________________________________________ +| | | | | +| Saponification | Acidity | Titre, | Refractive | +| Equivalent. | (as Oleic Acid) | °C. | Index | +| | Per Cent. | | at 25° C. | +|________________|_________________|________|____________| +| | | | | +| 225 | 4.4 | 24 | 1.4553 | +| 227 | 7.7 | 23.8 | 1.4553 | +|________________|_________________|________|____________| + +Palm-nut oil should absorb 10 to 13 per cent. iodine. + +_Olive Oil._--The olive is extensively grown in Southern Europe and in +portions of Asia and Africa bordering the Mediterranean Sea. The fruit +of this tree yields the oil. + +The free fatty acid content of olive oil varies very considerably. Very +fine oils contain less than 1 per cent. acidity; commercial oils may be +graded according to their free acidity, _e.g._, under 5 per cent., under +10 per cent., etc., and it entirely depends upon the desired price of +the resultant soap as to what grade would be used. The following is a +typical sample for use in the production of high-class toilet soap:-- + +_________________________________________________________ +| | | | | +| Saponification | Acidity | Titre, | Refractive | +| Equivalent. | (as Oleic Acid) | °C. | Index | +| | Per Cent. | | at 15° C. | +|________________|_________________|________|____________| +| | | | | +| 288 | 1.8 | 21 | 1.4704 | +|________________|_________________|________|____________| + +Olive oil should absorb 80 to 83 per cent. iodine. + +_Olive-kernel oil_, more correctly termed _Sulphur olive oil_. + +The amount of free fatty acids is always high and ranges from 40-70 per +cent., and, of course, its glycerol content is proportionately variable. +The free acidity increases very rapidly, and is, doubtless, due to the +decomposition of the neutral oil by the action of hydrolytic ferment. + +A representative sample of a parcel tested:-- + + _______________________________________________ +| | | | +| Saponification | Acidity | Refractive | +| Equivalent. | (as Oleic Acid) | Index | +| | Per Cent. | at 20° C. | +|________________|_________________|____________| +| | | | +| 298 | 40.96 | 1.4666 | +|________________|_________________|____________| + +_Palm oil_ is produced from the fruit of palm trees, which abound along +the west coast of Africa. Lagos is the best quality, whilst Camaroons, +Bonny, Old Calabar and New Calabar oils are in good request for +bleaching purposes. + +Analysis of typical samples of crude palm oil has given:-- + + _________________________________________________________ +| | | | | +| Saponification | Acidity | Titre, | Water and | +| Equivalent. | (as Oleic Acid) | °C. | Impurities, | +| | Per Cent. | | Per Cent. | +|________________|_________________|________|_____________| +| | | | | +| 278 | 10.7 | 45 | 1.6 | +| 280 | 31.2 | 44.5 | 2.8 | +|________________|_________________|________|_____________| + +Palm oil should absorb 51 to 56 per cent. iodine. + +In the lower qualities we have examples of the result of hydrolytic +decomposition by enzymes, the free acidity often amounting to 70 per +cent. + +_Cotton-seed Oil._--This oil is expressed from the seeds separated from +the "wool" of the various kinds of cotton tree largely cultivated in +America and Egypt. + +In its crude state cotton-seed oil is a dark fluid containing +mucilaginous and colouring matter, and is not applicable for +soap-making. The following figures are representative of well-refined +cotton-seed oils:-- + + _________________________________________________________________________ +| | | | | | +| Specific | Saponification | Acidity | Titre, | Refractive | +| Gravity | Equivalent. | (as Oleic Acid) | °C. | Index | +| at 15° C. | | Per Cent. | | at 20° C. | +|___________|________________|_________________|________|____________| +| | | | | | +| 0.9229 | 290 | 0.24 | 33.6 | 1.4721 | +| 0.924 | 299 | 0.39 | 35 | 1.4719 | +|___________|________________|_________________|________|____________| + +Cotton-seed oil should absorb 104 to 110 per cent. iodine. + +_Cotton-seed Stearine._--The product obtained by pressing the deposit +which separates on chilling refined cotton-seed oil. + +A typical sample tested:-- + + ___________________________________________ +| | | | +| Saponification | Acidity | Titre, | +| Equivalent. | (as Oleic Acid) | °C. | +| | Per Cent. | | +|________________|_________________|________| +| | | | +| 285.1 | 0.05 | 38 | +|________________|_________________|________| + +_Arachis Oil._--The earth-nut or ground-nut, from which arachis oil is +obtained, is extensively cultivated in North America, India and Western +Africa. Large quantities are exported to Marseilles where the oil is +expressed. Arachis oil enters largely into the composition of Marseilles +White Soaps. + +Representative samples of commercial and refined oils tested:-- + + ______________________________________________________________________ +| | | | | | | +| | Specific | Saponi- | Acidity | | Refractive | +| | Gravity | fication | (as Oleic | Titre, | Index | +| | at 15° C. | Equi- | Acid) | °C. | at 20° C. | +| | | valent | Per Cent. | | | +|____________|___________|___________|___________|________|____________| +| | | | | | | +| Commercial | 0.9184 | 298 | 2.6 | 28.6 | | +| Refined | 0.9205 | 285 | 0.22 | 24.0 | 1.4712 | +|____________|___________|___________|___________|________|____________| + +Arachis oil should absorb 90 to 98 per cent. iodine. + +_Maize Oil._--America (U.S.) produces very large quantities of maize +oil. + +Typical samples of crude and refined oil gave these figures:-- + + ______________________________________________________________________ +| | | | | | | +| | Specific | Saponi- | Acidity | | Refractive | +| | Gravity | fication | (as Oleic | Titre, | Index | +| | at 15° C. | Equi- | Acid) | °C. | at 20° C. | +| | | valent | Per Cent. | | | +|____________|___________|___________|___________|________|____________| +| | | | | | | +| Crude | 0.9246 | 294 | 1.41 | 15 | | +| Refined | 0.9248 | 294.1 | 0.40 | 17.2 | 1.4766 | +|____________|___________|___________|___________|________|____________| + +Maize oil should absorb 120 to 128 per cent. iodine. + +_Sesame Oil._--Sesame oil is very largely pressed in Southern France +from the seeds of the sesame plant which is cultivated in the Levant, +India, Japan and Western Africa. + +A fairly representative sample of French expressed oil tested:-- + + ____________________________________________________________________ +| | | | | | +| Specific | Saponification | Acidity | Titre, | Refractive | +| Gravity | Equivalent. | (as Oleic Acid) | °C. | Index | +| at 15° C. | | Per Cent. | | at 20° C. | +|___________|________________|_________________|________|____________| +| | | | | | +| 0.9227 | 295.2 | 1.84 | 22.8 | 1.4731 | +|___________|________________|_________________|________|____________| + +Sesame oil should absorb 108 to 110 per cent. iodine. + +_Linseed Oil._--Russia, India, and Argentine Republic are the principal +countries which extensively grow the flax plant, from the seeds of which +linseed oil is pressed. It is used to a limited extent in soft-soap +making. + +A good sample gave on analysis:-- + + ____________________________________________________________________ +| | | | | | +| Specific | Saponification | Acidity | Titre, | Refractive | +| Gravity | Equivalent. | (as Oleic Acid) | °C. | Index | +| at 15° C. | | Per Cent. | | at 15° C. | +|___________|________________|_________________|________|____________| +| | | | | | +| 0.935 | 292 | 1.2 | 20 | 1.4840 | +|___________|________________|_________________|________|____________| + +Linseed oil should absorb 170 to 180 per cent. iodine. + +_Hemp-seed oil_ is produced from the seeds of the hemp plant which grows +in Russia. This oil is used in soft soap-making, more particularly on +the Continent. + +A typical sample gave the following figures:-- + + __________________________________________________ +| | | | | +| Specific | Saponification | Titre, | | +| Gravity | Equivalent. | °C. | Iodine No. | +| at 15° C. | | | | +|___________|________________|________|____________| +| | | | | +| 0.926 | 292.6 | 15.8 | 143 | +|___________|________________|________|____________| + +_Sunflower oil_ is produced largely in Russia. + +A specimen tested:-- + + ____________________________________________________________________ +| | | | | | +| Specific | Saponification | Acidity | Titre, | | +| Gravity | Equivalent. | (as Oleic Acid) | °C. | Iodine No. | +| at 15° C. | | Per Cent. | | | +|___________|________________|_________________|________|____________| +| | | | | | +| 0.9259 | 290.7 | 0.81 | 17 | 126.2 | +|___________|________________|_________________|________|____________| + +_Castor Oil._--The castor oil plant is really a native of India, but it +is also cultivated in the United States (Illinois) and Egypt. + +A typical commercial sample tested:-- + + ________________________________________________________________________ +| | | | | | | +| Saponi- | Acidity | | | Optical | Refractive | +| fication | (as Oleic | Titre, | Iodine No. | Rotation | Index | +| Equi- | Acid) | °C. | | [alpha]_{D} | at 25° C. | +| valent | Per Cent. | | | | | +|___________|___________|________|____________|_____________|____________| +| | | | | | | +| 310 | 1.5 | 2.8 | 84.1 | + 4° 50' | 1.4787 | +|___________|___________|________|____________|_____________|____________| + +_Fish and Marine Animal Oils._--Various oils of this class have, until +recently, entered largely into the composition of soft soaps, but a +demand has now arisen for soft soaps made from vegetable oils. + +We quote a few typical analyses of these oils:-- + + _________________________________________________________________________ +| | | | | | | +| | Specific | Saponi- | Acidity | | Unsaponi- | +| | Gravity | fication | (as Oleic | Titre, | fiable | +| | at 15°C. | Equi- | Acid) | °C. | Matter | +| | | valent | Per Cent. | | Per Cent. | +|__________________|__________|__________|___________|________|___________| +| | | | | | | +| Pale seal oil | 0.9252 | 289 | 0.947 | 15.5 | 0.8 | +| Straw seal oil | 0.9231 | 288 | 4.77 | 15.8 | 1.2 | +| Brown seal oil | 0.9253 | 291 | 16.38 | 16.2 | 1.9 | +| Whale oil | 0.9163 | 297 | 1.49 | 16.1 | 1.8 | +| Dark whale oil | 0.9284 | 303 | 12.60 | 21.8 | 2.4 | +| Japan fish oil | 0.9336 | 296 | 4.79 | 26 | 0.67 | +| Japan fish oil | 0.9325 | 302 | 10.43 | 28 | 1.55 | +| Brown cod oil | 0.9260 | 313 | 14.91 | 21.8 | 1.9 | +| Pure herring oil | 0.9353 | 288 | 11.39 | 21.6 | 1.5 | +| Kipper oil | 0.9271 | 297 | 5.14 | 22.7 | 3.25 | +|__________________|__________|__________|___________|________|___________| + +_Waste Fats._--Under this classification may be included marrow fat, +skin greases, bone fats, animal grease, melted stuff from hotel and +restaurant refuse, and similar fatty products. The following is a fair +typical selection:-- + + _______________________________________________________________ +| | | | | +| | Saponification | Acidity | Titre, | +| | Equivalent. | (as Oleic Acid) | °C. | +| | | Per Cent. | | +|___________________|________________|_________________|________| +| | | | | +| Marrow fat | 283.3 | 3.6 | 38.7 | +| White skin grease | 287.2 | 4.3 | 36.4 | +| Pale skin grease | 286.3 | 9.87 | 35.7 | +| Pale bone fat | 289.7 | 8.8 | 40.7 | +| Brown bone fat | 289.1 | 11.0 | 41 | +| Brown bone fat | 292 | 20.5 | 40.2 | +| Animal grease | 289.4 | 38.1 | 40.4 | +| Melted stuff | 286.3 | 12.8 | 37.7 | +|___________________|________________|_________________|________| + +The materials in the above class require to be carefully examined for +the presence of unsaponifiable matter, lime salts and other impurities. + +_Fatty Acids._--We have already described the various methods of +liberating fatty acids by hydrolysis or saponification. + +Under this heading should also be included stearines produced by +submitting distilled fat to hydraulic pressure, the distillates from e +from unsaponifiable matter, cocoa-nut oleine, a bye-product from the +manufacture of edible cocoa-nut butter and consisting largely of free +acids, and palm-nut oleine obtained in a similar manner from palm-nut +oil. + +These are all available for soap-making. + + +LESS-KNOWN OILS AND FATS OF LIMITED USE. + +_Shea Butter._--Shea butter is extracted from the kernels of the _Bassia +Parkii_ and exported from Africa and Eastern India. This fat is somewhat +tough and sticky, and the amount of unsaponifiable matter present is +sometimes considerable. Samples examined by us gave the following +data:-- + + _______________________________________________________________ +| | | | | +| Saponification | Acidity | Titre, | Refractive | +| Equivalent. | (as Oleic Acid) | °C. | Index | +| | Per Cent. | | at 60° C. | +|________________|_________________|________|___________________| +| | | | | +| 313 | 8.2 | 53.2 | 1.4566 | +| 303 | 7.33 | 53 | 1.4558 | +| | | | 1.4471 (F. Acids) | +|________________|_________________|________|___________________| + +_Mowrah-seed Oil._--The mowrah-seed oil now offered for soap-making is +derived from the seeds of _Bassia longifolia_ and _Bassia latifolia_. It +is largely exported from India to Belgium, France and England. The +following are the results of some analyses made by us:-- + + _________________________________________________________ +| | | | | +| Saponification | Acidity | Titre, | Refractive | +| Equivalent. | (as Oleic Acid) | °C. | Index | +| | Per Cent. | | at 60° C. | +|________________|_________________|________|____________| +| | | | | +| 291 | 10 | 43.4 | 1.4518 | +| 291.5 | 7.1 | 42.7 | | +| 291.2 | 9.9 | 43.8 | | +| 292 | 11.26 | 40.5 | | +|________________|_________________|________|____________| + +_Chinese vegetable tallow_ is the name given to the fat which is found +coating the seeds of the "tallow tree" (_Stillingia sebifera_) which is +indigenous to China and has been introduced to India where it +flourishes. The following is a typical sample:-- + + _____________________________________ +| | | | +| Saponification | Acidity | Titre, | +| Equivalent | Per Cent. | °C. | +|________________|___________|________| +| | | | +| 280.2 | 5.24 | 52.5 | +|________________|___________|________| + +The seeds of the "tallow tree" yield an oil (stillingia oil) having +drying properties. + +_Borneo Tallow._--The kernels of several species of _Hopea_ (or +_Dipterocarpus_), which flourish in the Malayan Archipelago, yield a fat +known locally as Tangawang fat. This fat is moulded (by means of bamboo +canes) into the form of rolls about 3 inches thick, and exported to +Europe as Borneo Tallow. + +A sample tested by one of us gave the following data:-- + + ___________________________________________ +| | | | +| Saponification | Acidity | Titre, | +| Equivalent. | (as Oleic Acid) | °C. | +| | Per Cent. | | +|________________|_________________|________| +| | | | +| 292 | 36 | 50.8 | +|________________|_________________|________| + +_Kapok oil_ is produced from a tree which is extensively grown in the +East and West Indies. The Dutch have placed it on the market and the +figures given by Henriques (_Chem. Zeit._, 17, 1283) and Philippe +(_Monit. Scient._, 1902, 730), although varying somewhat, show the oil +to be similar to cotton-seed oil. + + +VARIOUS NEW FATS AND OILS SUGGESTED FOR SOAP-MAKING. + +_Carapa_ or _Andiroba oil_, derived from the seeds of a tree (_Carapa +Guianensis_) grown in West Indies and tropical America, has been +suggested as suitable for soap-making. Deering (_Imperial Institute +Journ._, 1898, 313) gives the following figures:-- + + ____________________________________________ +| | | | +| Saponification | Acidity | Melting Point | +| Equivalent | Per Cent. | of Fatty | +| | | Acids, °C. | +|________________|___________|_______________| +| | | | +| 287 | 12 | 89 | +|________________|___________|_______________| + +Another observer (_Rev. Chem. Ind._, 13, 116) gives the setting point of +the fatty acids as 56.4° C. + +_Candle-nut oil_ obtained from the seeds of a tree flourishing in India +and also the South Sea Islands. + +The following figures have been published:-- + + _____________________________________________________________________________ +| | | | | +| Saponi- | | | | +| fication | Titre,| Iodine No. | Observers.| References. +| Equiv- | | | | +| alent.[1] | °C. | | | +|___________|_______|____________|____________|_______________________________ +| | | | | +| 299-304.9 | 13 | 136.3-139.3| De Negri |_Chem. Centr._, 1898, p. 493. +| 291 | | 163.7 | Lewkowitsch|_Chem. Revue_, 1901, p. 156. +| 296 | 12.5 | 152.8 | Kassler |_Farben-Zeitung_, 1903, p. 359. +|___________|_______|____________|____________|_______________________________ + +_Curcas oil_ is produced in Portugal from the seeds of the "purging nut +tree," which is similar to the castor oil plant, and is cultivated in +Cape Verde Islands and other Portuguese Colonies. + +The following data have been observed:-- + +______________________________________________________________________________ +| | | | | +| Saponi- | | | | +| fication | Titre,| Iodine No. | Observers.| References. +| Equiv- | | | | +| alent.[2] | °C. | | | +|___________|_______|____________|____________|_______________________________ +| | | | | +| 291.4 | 0.36 | 99.5 | Archbut |_J. S. C. Ind._, 1898, p. 1010. +| 290.3 | 4.46 | 98.3 | Lewkowitsch|_Chem. Revue_, 1898, p. 211. +| 283.1 | 0.68 | 107.9 | Klein |_Zeits. angew. Chem._, +| | | | | 1898, p. 1012. +|___________|_______|____________|____________|_______________________________ + +The titre is quoted by Lewkowitsch as 28.6° C. + +_Goa butter_ or _Kokum butter_ is a solid fat obtained from the seeds of +_Garcinia indica_, which flourishes in India and the East Indies. +Crossley and Le Sueur (_Journ. Soc. Chem. Industry_, 1898, p. 993) +during an investigation of Indian oils obtained these results:-- + + _________________________________________ +| | | | +| Saponification | Acidity | Iodine No. | +| Equivalent.[3] | Per Cent. | | +|________________|___________|____________| +| | | | +| 300 | 7.1 | 34.2 | +|________________|___________|____________| + +_Safflower oil_ is extracted from the seeds of the _Carthamus +tinctorius_, which, although indigenous to India and the East Indies, is +extensively cultivated in Southern Russia (Saratowa) and German East +Africa. Its use has been suggested for soft-soap making. The following +figures have been published:-- + + ____________________________________________________________________________ +| | | | | +| | Saponi | | | +| |fication | Iodine | Observers. | References. +| | Equiv- | No. | | +| |alent.[4]| | | +|_________|_________|________|_____________|_________________________________ +| | | | | +| Average | 295.5 | 141.29 | Crossley and| _J. S. C. Ind._, 1898, p. 992; +| of | | | Le Sueur | _J. S. C. Ind._, 1900, p. 104. +| Twelve | 287.1 | 141.6 | Shukoff |_Chem. Revue_, 1901, p. 250. +| Samples | 289.2 | 130 | Tylaikow |_Chem. Revue_, 1902, p. 106. +| | 293.7 | 142.2 | Fendler |_Chem. Zeitung_, 1904, p. 867. +|_________|_________|________|_____________|_________________________________ + +_Maripa fat_ is obtained from the kernels of a palm tree flourishing in +the West Indies, but, doubtless, the commercial fat is obtained from +other trees of the same family. It resembles cocoa-nut oil and gives the +following figures:-- + + ___________________________________________________________________________ +| | | | | +| Saponi- | | Melting | | +| fication | | Point | | +| Equiv- | Iodine | of Fatty | | +| alent.[5]| No. | Acids, °C.| Observer. | Reference. +|__________|________|___________|___________|_______________________________ +| | | | | +| 217 | 9.49 | 25 | Bassière |_J. S. C. Ind._, 1903, p. 1137. +|__________|________|___________|___________|_______________________________ + +_Niam fat_, obtained from the seeds of _Lophira alata_, which are found +extensively in the Soudan. The fat, as prepared by natives, has been +examined by Lewkowitsch, and more recently Edie has published the +results of an analysis. The figures are as follows:-- + +__________________________________________________________________________ +| | | | | +| Saponi- | | | | +| fication | Titre,| Iodine | Observers.| References. +| Equiv- | | No. | | +| alent.[6] | °C. | | | +|___________|_______|________|____________|_______________________________ +| | | | | +| 295.1 | 78.12 | 42.5 | Lewkowitsch|_J. S. C. Ind._, 1907, p. 1266. +| 287.7 | 75.3 | | Edïe. |_Quart. J. Inst. Comm. +| | | | | Research in Tropics._ +|___________|_______|________|____________|_______________________________ + + +_Cohune-nut oil_ is produced from the nuts of the cohune palm, which +flourishes in British Honduras. This oil closely resembles cocoa-nut and +palm-nut oils and is stated to saponify readily and yield a soap free +from odour. The following figures, obtained in the Laboratory of the +Imperial Institute, are recorded in the official _Bulletin_, 1903, p. +25:-- + + ________________________________________________ +| | | | +| Saponification | Iodine No. | Melting Point of | +| Equivalent. | | Fatty Acids, °C. | +|________________|____________|__________________| +| | | | +| 253.9-255.3 | 12.9-13.6 | 27-30 | +|________________|____________|__________________| + +_Mafoureira_ or _Mafura tallow_ from the nuts of the mafoureira tree, +which grows wild in Portuguese East Africa. The following figures are +published:-- + +______________________________________________________________________________ +| | | | +| Saponi- | | | +| fication | | Iodine | References. +| Equi- | | No. | +| valent. | | | +|_____________|________________|___________|___________________________________ +| | Titre, °C. | | +| 253.8 | 44-48 | 46.14 | De Negri and Fabris, _Annal. del +| | | | Lab. Chim. Delle Gabelle_, +| | | | 1891-2, p. 271. +| | Acidity | | +| | (as Oleic Acid)| | +| | Per Cent. | | _Bulletin Imp. Inst._, +| 232.8-233.7 | 21.26 | 47.8-55.8 | 1903, p. 27. +|_____________|________________|___________|___________________________________ + +_Pongam oil_, obtained from the beans of the pongam tree, which +flourishes in East India, has been suggested as available for the soap +industry, but the unsaponifiable matter present would militate against +its use. Lewkowitsch (_Analyst_, 1903, pp. 342-44) quotes these +results:-- + + + _____________________________________________________________________ +| | | | | | +| | Saponi- | | | | +| | fication | Iodine | Acidity, | Unsaponifiable, | +| | Equi- | No. | Per Cent. | Per Cent. | +| | valent.[7] | | | | +|_________________|____________|________|___________|_________________| +| | | | | | +| Oil extracted | 315 | 94 | 3.05 | 9.22 | +| in laboratory | | | | | +| Indian specimen | 306 | 89.4 | 0.5 | 6.96 | +|_________________|____________|________|___________|_________________| + +_Margosa oil_ is obtained from the seeds of _Melia azedarach_, a tree +which is found in most parts of India and Burma. + +Lewkowitsch (_Analyst_, 1903, pp. 342-344) gives these figures:-- + + __________________________________ +| | | | +| Saponification | Iodine | Titre, | +| Equivalent.[8] | No. | °C. | +|________________|________|________| +| | | | +| 284.9 | 69.6 | 42 | +|________________|________|________| + +_Dika fat_ or _Wild Mango oil_ is obtained from the seed kernels of +various kinds of _Irvingia_ by boiling with water. Lemarié (_Bulletin +Imp. Inst._, 1903, p. 206) states that this fat is used in the place of +cocoa-nut oil in the manufacture of soap. Lewkowitsch (_Analyst_, 1905, +p. 395) examined a large sample of dika fat obtained from seeds of +_Irvingia bateri_ (South Nigeria) and gives the following data:-- + + ____________________________________________________ +| | | | | +| Saponification | Iodine | Titre, | Unsaponifiable, | +| Equivalent.[9] | No. | °C. | Per Cent. | +|________________|________|________|_________________| +| | | | | +| 229.4 | 5.2 | 34.8 | 0.73 | +|________________|________|________|_________________| + +_Baobab-seed Oil._--Balland (_Journ. Pharm. Chem._, 1904, p. 529, +abstracted in _Journ. Soc. Chem. Ind._, 1905, p. 34) states that the +natives of Madagascar extract, by means of boiling water, from the seeds +of the baobab tree, a whitish solid oil, free from rancidity, and +possessed of an odour similar to Tunisian olive oil. He suggests that it +may, with advantage, replace cocoa-nut oil in soap manufacture. + +_Persimmon-seed Oil._--Lane (_J. S. C. Ind._, 1905, p. 390) gives +constants for this oil which he describes as semi-drying, of brownish +yellow colour, and having taste and odour like pea-nut (arachis) oil. +The following are taken from Lane's figures:-- + + ___________________________________ +| | | | +| Saponification | Iodine | Titre, | +| Equivalent.[10] | No. | °C. | +|_________________|________|________| +| | | | +| 298.4 | 115.6 | 20.2 | +|_________________|________|________| + +_Wheat oil_, extracted from the wheat germ by means of solvents, has +been suggested as applicable for soap-making (H. Snyder, abstr. _J. S. +C. Ind._, 1905, p. 1074). The following figures have been published:-- + +_______________________________________________________________________________ +| | | | | | +| Saponi- | | | | | +| fication | Acidity,| Iodine | Titre, | Observers. | References. +| Equiv- | Per | No. | | | +| alent.[11]| Cent. | | °C. | | +|___________|_________|________|________|_____________|________________________ +| | | | | | +| 306 | 5.65 | 115.17 | 29.7 | De Negri. | _Chem. Zeit._, 1898 +| | | | | | (abstr. _J. S. C. I._, +| | | | | | 1898, p. 1155). +| 297 | 20 | 115.64 | | Frankforter | _J. Amer. C. Soc._, +| | | | | & Harding | 1899, 758-769 (abstr. +| | | | | | in _J. S. C. I._, +| | | | | | 1899, p. 1030). +|___________|_________|________|________|_____________|________________________ + +_Tangkallah fat_, from the seeds of a tree growing in Java and the +neighbouring islands, is suitable for soap-making. Schroeder (_Arch. +Pharm._, 1905, 635-640, abstracted in _J. S. C. Ind._, 1906, p. 128) +gives these values:-- + + _______________________________________________________ +| | | | | +| Saponification | Acidity, | Iodine | Unsaponifiable, | +| Equivalent.[12]| Per Cent. | No. | Per Cent. | +|________________|___________|________|_________________| +| | | | | +| 209 | 1.67 | 2.28 | 1.44 | +|________________|___________|________|_________________| + +It is a hard fat, nearly white, possessing neither taste nor +characteristic odour and solidifying at about 27° C. + +_Oil of Inoy-kernel._--(_Bulletin Imp. Inst._, 1906, p. 201). The seeds +of Poga oleosa from West Africa yield on extraction an oil which gives +the figures quoted below, and is suggested as a soap-maker's material:-- + + __________________________________ +| | | | +| Saponification | Iodine | Titre, | +| Equivalent. | No. | °C. | +|________________|________|________| +| | | | +| 304 | 89.75 | 22 | +|________________|________|________| + + +ROSIN. + +Rosin is the residuum remaining after distillation of spirits of +turpentine from the crude oleo-resin exuded by several species of the +pine, which abound in America, particularly in North Carolina, and also +flourish in France and Spain. The gigantic forests of the United States +consist principally of the long-leaved pine, _Pinus palustris +(Australis)_, whilst the French and Spanish oleo-resin is chiefly +obtained from _Pinus pinaster_, which is largely cultivated. + +Rosin is a brittle, tasteless, transparent substance having a smooth +shining fracture and melting at about 135° C. (275° F.). The American +variety possesses a characteristic aromatic odour, which is lacking in +those from France and Spain. It is graded by samples taken out of the +top of every barrel, and cut into 7/8 of an inch cubes, which must be +uniform in size--the shade of colour of the cube determines its grade +and value. + +The grades are as follows:-- + + W. W. (Water white.) + W. G. (Window glass.) + N. (Extra pale.) + M. (Pale.) + K. (Low pale.) + I. (Good No. 1.) + H. (No. 1.) + G. (Low No. 1.) + F. (Good No. 2.) + E. (No. 2.) + D. (Good strain.) + C. (Strain.) + B. (Common strain.) + A. (Common.) + +Unsaponifiable matter is present in rosin in varying amounts. + +Below are a few typical figures taken from a large number of collated +determinations:-- + + ________________________________________________________________ +| | | | | | +| | Saponification | Total | Free | Iodine | +| | Equivalent. | Acid No. | Acid No. | No. | +|________________|________________|__________|__________|________| +| | | | | | +| American W. W. | 330.5 | 169.7 | 119.1 | 126.9 | +| American N. | 312.3 | 179.6 | 161.4 | 137.8 | +| French | 320.5 | 175 | 168 | 120.7 | +| Spanish | 313.4 | 179 | 160 | 129.8 | +|________________|________________|__________|__________|________| + + +ALKALI (CAUSTIC AND CARBONATED). + +The manufacture of alkali was at one time carried on in conjunction with +soap-making, but of late years it has become more general for the soap +manufacturer to buy his caustic soda or carbonated alkali from the +alkali-maker. + +Although there are some alkali-makers who invoice caustic soda and soda +ash in terms of actual percentage of sodium oxide (Na_{2}O), it is the +trade custom to buy and sell on what is known as the English degree, +which is about 1 per cent. higher than this. + +The English degree is a survival of the time when the atomic weight of +sodium was believed to be twenty-four instead of twenty-three, and, +since the error on 76 per cent. Na_{2}O due to this amounts to about 1 +per cent., may be obtained by adding this figure to the sodium oxide +really present. + +_Caustic soda_ (sodium hydrate) comes into commerce in a liquid form as +90° Tw. (and even as high as 106° Tw.), and other degrees of dilution, +and also in a solid form in various grades as 60°, 70°, 76-77°, 77-78°. +These degrees represent the percentage of sodium oxide (Na_{2}O) present +plus the 1 per cent. The highest grade, containing as it does more +available caustic soda and less impurities, is much more advantageous in +use. + +_Carbonate of soda_ or _soda ash_, 58°, also termed "light ash," and +"refined alkali". This is a commercially pure sodium carbonate +containing about 0.5 per cent. salt (NaCl). The 58° represents the +English degrees and corresponds to 99 per cent. sodium carbonate +(Na_{2}CO_{3}). + +_Soda ash_, 48°, sometimes called "caustic soda ash," often contains +besides carbonate of soda, 4 per cent. caustic soda (sodium hydrate), +and 10 per cent. salt (sodium chloride), together with water and +impurities. + +The 48 degrees refers to the amount of alkali present in terms of sodium +oxide (Na_{2}O), but expressed as English degrees. + +_Caustic potash_ (potassium hydrate) is offered as a liquid of 50-52° B. +(98-103° Tw.) strength, and also in solid form as 75-80° and 88-92°. The +degrees in the latter case refer to the percentage of potassium hydrate +(KHO) actually present. + +_Carbonate of Potash._--The standard for refined carbonate of potash is +90-92 per cent. of actual potassium carbonate (K_{2}CO_{3}) present, +although it can be obtained testing 95-98 per cent. + + +OTHER MATERIALS. + +_Water._--Water intended for use in soap-making should be as soft as +possible. If the water supply is hard, it should be treated chemically; +the softening agents may be lime and soda ash together, soda ash alone, +or caustic soda. There are many excellent plants in vogue for water +softening, which are based on similar principles and merely vary in +mechanical arrangement. The advantages accruing from the softening of +hard water intended for steam-raising are sufficiently established and +need not be detailed here. + +_Salt_ (sodium chloride or common salt, NaCl) is a very important +material to the soap-maker, and is obtainable in a very pure state. + +Brine, or a saturated solution of salt, is very convenient in +soap-making, and, if the salt used is pure, will contain 26.4 per cent. +sodium chloride and have a density of 41.6° Tw. (24.8° B.). + +The presence of sulphates alters the density, and of course the sodium +chloride content. + +Salt produced during the recovery of glycerine from the spent lyes often +contains sulphates, and the density of the brine made from this salt +ranges higher than 42° Tw. (25° B.). + +_Soapstock._--This substance is largely imported from America, where it +is produced from the dark-coloured residue, termed mucilage, obtained +from the refining of crude cotton-seed oil. Mucilage consists of +cotton-seed oil soap, together with the colouring and resinous +principles separated during the treatment of the crude oil. The +colouring matter is removed by boiling the mucilage with water and +graining well with salt; this treatment is repeated several times until +the product is free from excess of colour, when it is converted into +soap and a nigre settled out from it. + +Soapstock is sold on a fatty acid basis; the colour is variable. + +FOOTNOTES: + +[1] Calculated by us from saponification value. + +[2] Calculated by us from saponification value. + +[3] Calculated by us from saponification value. + +[4] Calculated by us from saponification value. + +[5] Calculated by us from saponification value. + +[6] Calculated by us from saponification value. + +[7] Calculated by us from saponification value. + +[8] Calculated by us from saponification value. + +[9] Calculated by us from saponification value. + +[10] Calculated by us from saponification value. + +[11] Calculated by us from saponification value. + +[12] Calculated by us from saponification value. + + + + +CHAPTER IV. + +BLEACHING AND TREATMENT OF RAW MATERIALS INTENDED FOR SOAP-MAKING. + + _Palm Oil--Cotton-seed Oil--Cotton-seed "Foots"--Vegetable + Oils--Animal Fats--Bone Fat--Rosin._ + + +Having described the most important and interesting oils and fats used +or suggested for use in the manufacture of soap, let us now consider +briefly the methods of bleaching and treating the raw materials, prior +to their transference to the soap-pan. + +_Crude Palm Oil._--Of the various methods suggested for bleaching palm +oil, the bichromate process originated by Watts is undoubtedly the best. +The reaction may be expressed by the following equation, though in +practice it is necessary to use twice the amount of acid required by +theory:-- + + K_{2}Cr_{2}O_{7} + 14HCl = 2KCl + Cr_{2}Cl_{6} + 7H_{2}O + 6Cl. + + 6Cl + 3H_{2}O = 6HCl + 3O. + +The palm oil, freed from solid impurities by melting and subsidence, is +placed in the bleaching tank, and washed with water containing a little +hydrochloric acid. Having allowed it to rest, and drawn off the liquor +and sediment (chiefly sand), the palm oil is ready for treatment with +the bleaching reagent, which consists of potassium bichromate and +commercial muriatic acid. For every ton of oil, 22 to 28 lb. potassium +bichromate and 45 to 60 lb. acid will be found sufficient to produce a +good bleached oil. + +The best procedure is to act upon the colouring matter of the oil three +successive times, using in the first two treatments one-third of the +average of the figures just given, and in the final treatment an +appropriate quantity which can be easily gauged by the appearance of a +cooled sample of the oil. + +The potassium bichromate is dissolved in hot water and added to the +crude palm oil, previously heated to 125° F. (52° C.), the requisite +amount of muriatic acid being then run in and the whole well agitated by +means of air. The bright red colour of the oil gradually changes to dark +brown, and soon becomes green. The action having proceeded for a few +minutes, agitation is stopped, and, after allowing to settle, the green +liquor is withdrawn. + +When sufficiently bleached the oil is finally washed (without further +heating) with hot water (which may contain salt), to remove the last +traces of chrome liquor. + +If the above operation is carried out carefully, the colouring matter +will be completely oxidised. + +It is important, however, that the temperature should not be allowed to +rise above 130° F. (54° C.) during the bleaching of palm oil, otherwise +the resultant oil on saponification is apt to yield a soap of a "foxy" +colour. The bleached oil retains the characteristic violet odour of the +original oil. + +It has been suggested to use dilute sulphuric acid, or a mixture of this +and common salt, in the place of muriatic acid in the above process. + +_Crude Cotton-seed Oil._--The deep colouring matter of crude cotton-seed +oil, together with the mucilaginous and resinous principles, are removed +by refining with caustic soda lye. + +The chief aim of the refiner is to remove these impurities without +saponifying any of the neutral oil. The percentage of free fatty acids +in the oil will determine the quantity of caustic lye required, which +must only be sufficient to remove this acidity. + +Having determined the amount of free acidity, the quantity of caustic +soda lye necessary to neutralise it is diluted with water to 12° or 15° +Tw. (8° or 10° B.), and the refining process carried out in three +stages. The oil is placed in a suitable tank and heated by means of a +closed steam coil to 100° F. (38° C.), a third of the necessary weak +caustic soda lye added in a fine stream or by means of a sprinkler, and +the whole well agitated with a mechanical agitator or by blowing a +current of air through a pipe laid on the bottom of the tank. + +Prolonged agitation with air has a tendency to oxidise the oil, which +increases its specific gravity and refractive index, and will be found +in the soap-pan to produce a reddish soap. As the treatment proceeds, +the temperature may be carefully raised, by means of the steam coil, to +120° F. (49° C.). + +The first treatment having proceeded fifteen minutes, the contents of +the tank are allowed to rest; the settling should be prolonged as much +as possible, say overnight, to allow the impurities to precipitate well, +and carry down the least amount of entangled oil. Having withdrawn these +coloured "foots," the second portion of the weak caustic soda solution +is agitated with the partially refined oil, and, when the latter is +sufficiently treated, it is allowed to rest and the settled coloured +liquor drawn off as before. The oil is now ready for the final +treatment, which is performed in the same manner as the two previous +ones. On settling, a clear yellow oil separates. + +If desired, the oil may be brightened and filtered, after refining to +produce a marketable article, but if it is being refined for own use in +the soap-house, this may be omitted. + +The residue or "foots" produced during the refining of crude +cotton-seed oil, known in the trade as "mucilage," may be converted into +"soapstock" as mentioned in the preceding chapter, or decomposed by a +mineral acid and made into "black grease" ready for distillation by +superheated steam. + +_Vegetable Oils._--The other vegetable oils come to the soap-maker's +hand in a refined condition; occasionally, however, it is desirable to +remove a portion of the free fatty acids, which treatment also causes +the colouring matter to be preciptated. This is effected by bringing the +oil and a weak solution of caustic lye into intimate contact. Cocoa-nut +oil is often treated in this manner. Sometimes it is only necessary to +well agitate the oil with 1-1/2 per cent. of its weight of a 12° Tw. (8° +B.) solution of caustic soda and allow to settle. The foots are utilised +in the soap-pan. + +_Animal Fats._--Tallows are often greatly improved by the above alkaline +treatment at 165° F. (73° C.). It is one of the best methods and +possesses advantages over acid processes--the caustic soda removes the +free acid and bodies of aldehyde nature, which are most probably the +result of oxidation or polymerisation, whereas the neutral fat is not +attacked, and further, the alkaline foots can be used in the production +of soap. + +_Bone fat_ often contains calcium (lime) salts, which are very +objectionable substances in a soap-pan. These impurities must be removed +by a treatment with hydrochloric or sulphuric acid. The former acid is +preferable, as the lime salt formed is readily soluble and easily +removed. The fat is agitated with a weak solution of acid in a +lead-lined tank by blowing in steam, and when the treatment is complete +and the waste liquor withdrawn, the last traces of acid are well washed +out of the liquid fat with hot water. + +_Rosin._--Several methods have been suggested for bleaching rosin; in +some instances the constitution of the rosin is altered, and in others +the cost is too great or the process impracticable. + +The aim of these processes must necessarily be the elimination of the +colouring matter without altering the original properties of the +substance. This is best carried out by converting the rosin into a +resinate of soda by boiling it with a solution of either caustic soda or +carbonated alkali. The process is commenced by heating 37 cwt. of 17° +Tw. (11° B.) caustic soda lye, and adding 20 cwt. of rosin, broken into +pieces, and continuing the boiling until all the resinate is +homogeneous, when an addition of 1-1/2 cwt. of salt is made and the +boiling prolonged a little. On resting, the coloured liquor rises to the +surface of the resinate, and may be siphoned off (or pumped away through +a skimmer pipe) and the resinate further washed with water containing a +little salt. + +The treatment with carbonated alkali is performed in a similar manner. A +solution, consisting of 2-3/4 cwt. of soda ash (58°), in about four +times its weight of water, is heated and 20 cwt. of rosin, broken into +small pieces, added. The whole is heated by means of the open steam +coil, and care must be taken to avoid boiling over. Owing to the +liberation of CO_{2} gas, frothing takes place. A large number of +patents have been granted for the preparation of resinate of soda, and +many methods devised to obviate the boiling over. Some suggest mixing +the rosin and soda ash (or only a portion of the soda ash) prior to +dissolving in water; others saponify in a boiler connected with a trap +which returns the resinate to the pan and allows the carbonic-acid gas +to escape or to be collected. + +With due precaution the method can be easily worked in open vessels, +and, using the above proportions, there will be sufficient uncombined +rosin remaining to allow the resultant product to be pumped into the +soap with which it is intended to intermix it, where it will be finally +saponified thoroughly. + +The salt required, which, in the example given, would be 1-1/2 cwt., may +be added to the solution prior to the addition of rosin or sprinkled in +towards the finish of the boiling. When the whole has been sufficiently +boiled and allowed to rest, the liquor containing the colouring matter +will float over the resinate, and, after removal, may be replaced by +another washing. + +Many other methods have been suggested for the bleaching, refining and +treatment of materials intended for saponification, but the above +practical processes are successfully employed. + +All fats and oils after being melted by the aid of steam must be allowed +to thoroughly settle, and the condensed water and impurities withdrawn +through a trap arrangement for collecting the fatty matter. The molten +settled fatty materials _en route_ to the soap-pan should be passed +through sieves sufficiently fine to free them from suspended matter. + + + + +CHAPTER V. + +SOAP-MAKING. + + _Classification of Soaps--Direct Combination of Fatty Acids + with Alkali--Cold Process Soaps--Saponification under Increased + or Diminished Pressure--Soft Soap--Marine Soap--Hydrated Soaps, + Smooth and Marbled--Pasting or Saponification--Graining + Out--Boiling on Strength--Fitting--Curd Soaps--Curd + Mottled--Blue and Grey Mottled Soaps--Milling Base--Yellow + Household Soaps--Resting of Pans and Settling of + Soap--Utilisation of Nigres--Transparent Soaps--Saponifying + Mineral Oil--Electrical Production of Soap._ + + +Soaps are generally divided into two classes and designated "hard," and +"soft," the former being the soda salts, and the latter potash salts, of +the fatty acids contained in the material used. + +According to their methods of manufacture, soaps may, however, be more +conveniently classified, thus:-- + +(A) Direct combination of fatty acids with alkali. + +(B) Treatment of fat with definite amount of alkali and no separation of +waste lye. + +(C) Treatment of fat with indefinite amount of alkali and no separation +of waste lye. + +(D) Treatment of fat with indefinite amount of alkali and separation of +waste lye. + +(A) _Direct Combination of Fatty Acids with Alkali._--This method +consists in the complete saturation of fatty acids with alkali, and +permits of the use of the deglycerised products mentioned in chapter +ii., section 2, and of carbonated alkalies or caustic soda or potash. +Fatty acids are readily saponified with caustic soda or caustic potash +of all strengths. + +The saponification by means of carbonated alkali may be performed in an +open vat containing a steam coil, or in a pan provided with a removable +agitator. + +It is usual to take soda ash (58°), amounting to 19 per cent. of the +weight of fatty acids to be saponified, and dissolve it in water by the +aid of steam until the density of the solution is 53° Tw. (30° B.); then +bring to the boil, and, whilst boiling, add the molten fatty acids +slowly, but not continuously. + +Combination takes place immediately with evolution of carbonic acid gas, +which causes the contents of the vat or pan to swell, and frequently to +boil over. The use of the agitator, or the cessation of the flow of +fatty acids, will sometimes tend to prevent the boiling over. It is +imperative that the steam should not be checked but boiling continued +as vigorously as possible until all the alkali has been absorbed and the +gas driven off. + +The use of air to replace steam in expelling the carbonic acid gas has +been patented (Fr. Pat. 333,974, 1903). + +A better method of procedure, however, is to commence with a solution of +64° Tw. (35° B.) density, made from half the requisite soda ash (9-1/2 +per cent.), and when this amount of alkali has all been taken up by the +fatty acids (which have been added gradually and with continuous +boiling), the remaining quantity of soda ash is added in a dry state, +being sprinkled over each further addition of fatty acid. + +This allows the process to be more easily controlled and boiling over is +avoided. + +It is essential that the boiling by steam should be well maintained +throughout the process until all carbonic acid gas has been thoroughly +expelled; when that point is reached, the steam may be lessened and the +contents of the vat or pan gently boiled "on strength" with a little +caustic lye until it ceases to absorb caustic alkali, the soap being +finished in the manner described under (D). + +It is extremely difficult to prevent discoloration of fatty acids, hence +the products of saponification in this way do not compare favourably in +appearance with those produced from the original neutral oil or fat. + +(B) _Treatment of Fat with Definite Amount of Alkali and no Separation +of Waste Lye._--Cold-process soap is a type of this class, and its +method of production is based upon the characteristic property which the +glycerides of the lower fatty acids (members of the cocoa-nut-oil class) +possess of readily combining with a strong caustic soda solution at a +low temperature, and evolving sufficient heat to complete the +saponification. + +Sometimes tallow, lard, cotton-seed oil, palm oil and even castor oil +are used in admixture with cocoa-nut oil. The process for such soap is +the same as when cocoa-nut oil is employed alone, with the slight +alteration in temperature necessary to render the fats liquid, and the +amount of caustic lye required will be less. Soaps made of these blends +closely resemble, in appearance, milled toilet soaps. In such mixtures +the glycerides of the lower fatty acids commence the saponification, and +by means of the heat generated induce the other materials, which alone +would saponify with difficulty or only with the application of heat, to +follow suit. + +It is necessary to use high grade materials; the oils and fats should be +free from excess of acidity, to which many of the defects of +cold-process soaps may be traced. Owing to the rapidity with which free +acidity is neutralised by caustic soda, granules of soap are formed, +which in the presence of strong caustic lye are "grained out" and +difficult to remove without increasing the heat; the soap will thus tend +to become thick and gritty and sometimes discoloured. + +The caustic lye should be made from the purest caustic soda, containing +as little carbonate as possible; the water used for dissolving or +diluting the caustic soda should be soft (_i.e._, free from calcium and +magnesium salts), and all the materials carefully freed from particles +of dirt and fibre by straining. + +The temperature, which, of course, must vary with the season, should be +as low as is consistent with fluidity, and for cocoa-nut oil alone may +be 75° F. (24° C.), but in mixtures containing tallow 100° to 120° F. +(38° to 49° C.). + +The process is generally carried out as follows:-- + +The fluid cocoa-nut oil is stirred in a suitable vessel with half its +weight of 71.4° Tw. (38° B.) caustic soda lye at the same temperature, +and, when thoroughly mixed, the pan is covered and allowed to rest. It +is imperative that the oils and fats and caustic lye should be +intimately incorporated or emulsified. The agitating may be done +mechanically, there being several machines specially constructed for the +purpose. In one of the latest designs the caustic lye is delivered +through a pipe which rotates with the stirring gear, and the whole is +driven by means of a motor. + +The agitation being complete, chemical action takes place with the +generation of heat, and finally results in the saponification of the +fats. + +At first the contents of the pan are thin, but in a few hours they +become a solid mass. As the process advances the edges of the soap +become more transparent, and when the transparency has extended to the +whole mass, the soap is ready, after perfuming, to be framed and +crutched. + +The admixture of a little caustic potash with the caustic soda greatly +improves the appearance of the resultant product, which is smoother and +milder. + +The glycerine liberated during the saponification is retained in the +soap. + +Although it is possible, with care, to produce neutral soaps of good +appearance and firm touch by this method, cold-process soaps are very +liable to contain both free alkali and unsaponified fat, and have now +fallen considerably into disrepute. + +_Saponification under Increased or Diminished Pressure._--Soaps made by +boiling fats and oils, under pressure and _in vacuo_, with the exact +quantity of caustic soda necessary for complete combination, belong also +to this class. Amongst the many attempts which have at various times +been made to shorten the process of soap-making may be mentioned +Haywood's Patent No. 759, 1901, and Jourdan's French Patent No. 339,154, +1903. + +In the former, saponification is carried out in a steam-jacketed vacuum +chamber provided with an elaborate arrangement of stirrers; in the other +process fat is allowed to fall in a thin stream into the amount of lye +required for saponification, previously placed in the saponification +vessel, which is provided with stirring gear. + +When the quantities have been added, steam is admitted and +saponification proceeds. + +(C) _Treatment of Fat with Indefinite Amount of Alkali and no Separation +of Waste Lye._--_Soft soap_ is representative of this class. The +vegetable fluid oils (linseed, olive, cotton-seed, maize) are for the +most part used in making this soap, though occasionally bone fats and +tallow are employed. Rosin is sometimes added, the proportion ranging, +according to the grade of soap required, from 5 to 15 per cent. of the +fatty matter. + +The Soft Soap Manufacturers' Convention of Holland stipulate that the +materials used in soft-soap making must not contain more than 5 per +cent. rosin; it is also interesting to note that a patent has been +granted (Eng. Pat. 17,278, 1900) for the manufacture of soft soap from +material containing 50 per cent. rosin. + +Fish or marine animal oils--whale, seal, etc., once largely used as raw +material for soft soap, have been superseded by vegetable oils. + +The materials must be varied according to the season; during hot +weather, more body with a less tendency to separate is given by the +introduction of oils and fats richer in stearine; these materials also +induce "figging". + +The most important material, however, is the caustic potash lye which +should average 40° Tw. (24° B.), _i.e._, if a weak solution is used to +commence saponification, a stronger lye must be afterwards employed to +avoid excess of water in the soap, and these average 40° Tw. (24° B.). +The potash lye must contain carbonates, which help to give transparency +to the resultant soap. If the lye is somewhat deficient in carbonates, +they may be added in the form of a solution of refined pearl ash +(potassium carbonate). + +Caustic soda lye is sometimes admixed, to the extent of one-fourth, with +potash lye to keep the soap firmer during hot weather, but it requires +great care, as a slight excess of soda gives soft soap a bad appearance +and a tendency to separate. + +The process is commenced by running fatty matter and weak potash lyes +into the pan or copper, and boiling together, whilst the introduction of +oil and potash lye is continued. + +The saponification commences when an emulsion forms, and the lye is then +run in more quickly to prevent the mass thickening. + +Having added sufficient "strength" for complete saponification, the +boiling is continued until the soap becomes clear. + +The condition of the soap is judged by observing the behaviour of a +small sample taken from the pan and dropped on glass or iron. If the +soap is satisfactory it will set firm, have a short texture and slightly +opaque edge, and be quite clear when held towards the light. If the +cooled sample draws out in threads, there is an excess of water present. +If an opaque edge appears and vanishes, the soap requires more lye. If +the sample is turbid and somewhat white, the soap is too alkaline and +needs more oil. + +The glycerine liberated during saponification is contained in the soap +and no doubt plays a part in the production of transparency. + +_Hydrated soaps_, both smooth and marbled, are included in this +classification, but are _soda_ soaps. Soap made from cocoa-nut oil and +palm-kernel oil will admit of the incorporation of large quantities of a +solution of either salt, carbonate of soda, or silicate of soda, without +separation, and will retain its firmness. These materials are, +therefore, particularly adapted for the manufacture of marine soaps, +which often contain as much as 80 per cent. of water, and, being soluble +in brine, are capable of use in sea-water. For the same reason, +cocoa-nut oil enters largely into the constitution of hydrated soaps, +but the desired yield or grade of soap allows of a variation in the +choice of materials. Whilst marine soap, for example, is usually made +from cocoa-nut oil or palm-kernel oil only, a charge of 2/3 cocoa-nut +oil and 1/3 tallow, or even 2/3 tallow and 1/3 cocoa-nut oil, will +produce a paste which can carry the solutions of silicate, carbonate, +and salt without separation, and yield a smooth, firm soap. + +The fatty materials, carefully strained and freed from particles of dirt +and fibre, are boiled with weak caustic soda lye until combination has +taken place. Saponification being complete, the solution of salt is +added, then the carbonate of soda solution, and finally the silicate of +soda solution, after which the soap is boiled. When thoroughly mixed, +steam is shut off, and the soap is ready for framing. + +The marbled hydrated soap is made from cocoa-nut oil or a mixture of +palm-kernel oil and cocoa-nut oil with the aid of caustic soda lye +32-1/2° Tw. (20° B.). As soon as saponification is complete, the brine +and carbonate of soda solution are added, and the pan allowed to rest. + +The soap is then carefully tasted as to its suitability for marbling by +taking samples and mixing with the colouring solution (ultramarine mixed +with water or silicate of soda solution). If the sample becomes blue +throughout, the soap is too alkaline; if the colour is precipitated, the +soap is deficient in alkali. The right point has been reached when the +marbling is distributed evenly. Having thus ascertained the condition of +the pan, and corrected it if necessary, the colour, mixed in water or in +silicate of soda solution, is added and the soap framed. + +(D) _Treatment of Fat with Indefinite Amount of Alkali and Separation of +Waste Lye._--This is the most general method of soap-making. The various +operations are:-- + + (_a_) Pasting or saponification. + (_b_) Graining out or separation. + (_c_) Boiling on strength. + +And in the case of milling soap base and household soaps, + + (_d_) Fitting. + +(_a_) _Pasting or Saponification._--The melted fats and oils are +introduced into the soap-pan and boiled by means of open steam with a +caustic soda lye 14° to 23.5° Tw. (10° to 15° B.). Whether the fatty +matters and alkali are run into the pan simultaneously or separately is +immaterial, provided the alkali is not added in sufficient excess to +retard the union. + +The commencement of the saponification is denoted by the formation of an +emulsion. Sometimes it is difficult to start the saponification; the +presence of soap will often assist this by emulsifying the fat and thus +bringing it into intimate contact with the caustic soda solution. + +When the action has started, caustic soda lye of a greater density, 29° +to 33° Tw. (18° to 20° B.), is frequently added, with continued boiling, +in small quantities as long as it is being absorbed, which is +ascertained by taking out samples from time to time and examining them. + +There should be no greasiness in the sample, but when pressed between +finger and thumb it must be firm and dry. + +Boiling is continued until the faint caustic taste on applying the +cooled sample to the tongue is permanent, when it is ready for "graining +out". The pasty mass now consists of the soda salts of the fat (as +imperfect soap, probably containing emulsified diglycerides and +monoglycerides), together with water, in which is dissolved the +glycerine formed by the union of the liberated glyceryl radicle from the +fat with the hydroxyl radicle of the caustic soda, and any slight excess +of caustic soda and carbonates. The object of the next operation is to +separate this water (spent lye) from the soap. + +(_b_) _Graining Out or Separation._--This is brought about by the use of +common salt, in a dry form or in solution as brine, or by caustic soda +lye. Whilst the soap is boiling, the salt is spread uniformly over its +surface, or brine 40° Tw. (24° B.) is run in, and the whole well boiled +together. The soap must be thoroughly boiled after each addition of +salt, and care taken that too large a quantity is not added at once. + +As the soap is gradually thrown out of solution, it loses its smooth +transparent appearance, and becomes opaque and granular. + +When a sample, taken out on a wooden trowel, consists of distinct grains +of soap and a liquid portion, which will easily separate, sufficient +salt or brine has been added; the boiling is stopped and the spent lye +allowed to settle out, whilst the soap remains on the surface as a more +or less thick mass. + +The separated spent lye consists of a solution of common salt, +glycerine, and alkaline salts; the preparation of crude glycerine +therefrom is considered in chapter ix. + +The degree of separation of water (spent lye) depends upon the amount of +precipitant used. The aim is to obtain a maximum amount of spent lye +separated by the use of a minimum quantity of salt. + +The amount of salt required for "graining out" varies with the raw +material used. A tallow soap is the most easily grained, more salt is +required for cotton-seed oil soap, whereas soaps made from cocoa-nut and +palm-kernel oils require very large amounts of salt to grain out +thoroughly. Owing to the solubility in weak brine of these latter soaps, +it is preferable to grain them with caustic soda lye. This is effected +by adding, during boiling, sufficient caustic lye (32-1/2° Tw., 20° B.) +to produce the separation of the granules of soap. The whole is allowed +to rest; the separated half-spent lye is withdrawn and may be used for +the pasting of fresh materials. + +After the removal of the settled lye, the grained mass is boiled with +sufficient water to dissolve the grain and make it smooth ("close" it), +and is now ready for the next operation of "boiling on strength". + +(_c_) _Boiling on Strength or Clear Boiling._--This is the most +important operation and is often termed "making the soap". The object is +to harden the soap and to ensure complete saponification. + +Caustic soda lye (32-1/2° Tw., 20° B.) is gradually added until the soap +is again opened or grained, and boiling continued by the use of the dry +steam coil. As soon as the caustic soda lye is absorbed, another portion +is slowly added, and this is continued until the caustic soda or +"strength" remains permanent and the soapy mass, refusing to absorb +more, is thrown out of solution and grained. The granular mass will boil +steadily, and the boiling should be prolonged, as the last traces of +neutral oil are difficult to completely saturate with alkali. Thorough +saponification takes place gradually, and the operation cannot be +hurried; special care has to be bestowed upon this operation to effect +the complete combination of fat and alkali. + +After resting for several hours, half-spent lye settles to the bottom of +the pan. In the case of yellow soaps or milling bases the settled lye is +removed to a suitable receptacle and reserved for use in the +saponification of other material, and the soap is then ready for the +final operation of "fitting". + +(_d_) _Fitting._--If the operations just described have been properly +performed, the fitting should present no difficulty. The soap is boiled +with open steam, and water added until the desired degree of closing is +attained. As the water is thoroughly intermixed throughout the mass the +thick paste gradually becomes reduced to a smooth, thin consistence. +Samples are tested from time to time as to their behaviour in dropping +off a hot trowel held sideways; the thin layer should drop off in two or +three flakes and leave the surface of the trowel clean and dry. The soap +is then in a condition to allow the impurities to gravitate. According +to the required soap, the fit may be "coarse" ("open") when the flakes +drop off the trowel readily, or "fine" ("close") when the flakes only +leave the trowel with difficulty. + +If the dilution with water has been allowed to proceed too far, and too +fine a fit is produced, which would be denoted by the layer of soap not +leaving the trowel, a little caustic lye or brine may be very carefully +added and the whole well boiled until the desired condition is obtained. + +A good pressure of steam is now applied to the pan, causing the contents +to swell as high as possible, this greatly facilitating the settling of +impurities; steam is then turned off, the pan covered, and the boil +allowed to rest for several days. + +The art of fitting consists in leaving the contents of the pan in such a +condition that, on standing, all the impurities precipitate, and the +settled soap, containing the correct amount of water, is clear and +bright. + +The above is a general practical outline of the ordinary soap-boiling +process. It may be modified or slightly altered according to the fancy +of the individual soap-maker or the particular material it is desired to +use. Fats and oils not only vary in the amount of alkali they absorb +during saponification, but also differ in the strength of the alkali +they require. Tallow and palm oil require lye of a density of 15° to 18° +Tw. (10° to 12° B.), but cocoa-nut oil alone would not saponify unless +the lye was more concentrated, 33° to 42° Tw. (20° to 25° B.). +Cotton-seed oil requires weak lyes for saponification, and, being +difficult to saponify alone even with prolonged boiling, is generally +mixed with animal fat. + +When fats are mixed together, however, their varying alkali requirements +become modified, and once the saponification is begun with weak lye, +other materials are induced to take up alkali of a strength with which +alone they would not combine. + +It is considered the best procedure to commence the pasting or +saponification with weak lye. + +In order to economise tank space, it is the general practice to store +strong caustic lye (60° to 70° Tw., 33° to 37° B.) and to dilute it as +it is being added to the soap-pan by the simultaneous addition of water. + +Many manufacturers give all their soap a "brine wash" to remove the last +traces of glycerine and free the soap from carbonates. This operation +takes place prior to "fitting"; sufficient water is added to the boiling +soap to "close" it and then brine is run in to "grain" it. + +After resting, the liquor is withdrawn. + +Having described the necessary operations in general, we will now +consider their application to the preparation of various kinds of hard +soap. + +_Curd Soaps._--Tallow is largely used in the manufacture of white curd +soaps, but cocoa-nut oil sometimes enters into their composition. + +The first three operations above described, _viz._, pasting, graining +out, and boiling on strength, are proceeded with; the clear boiling by +means of a closed steam coil is continued until the "head" is boiled out +and the soap is free from froth. A sample taken and cooled should be +hard. Boiling is then stopped, and, after covering, the pan is allowed +to rest for eight to ten hours, when the soap is ready for filling into +frames, where it is crutched until perfectly smooth. + +_Curd mottled_ is usually made from melted kitchen stuff and bone +grease. + +Its preparation is substantially the same as for curd soap, but the +clear boiling is not carried so far. The art of curd mottled soap-making +lies in the boiling. If boiled too long the mottling will not form +properly, and, on the other hand, insufficient boiling will cause the +soap to contain an excess of entangled lye. Having boiled it to its +correct concentration the pan is allowed to rest about two hours, after +which the soap is ready for framing, which should be done expeditiously +and the frames covered up. + +Some lye, containing the impurities from the fats used, remains in the +interstices of the curd, unable to sink, and as the soap cools it is +enclosed and forms the mottling. The mottling may, therefore, be +considered as a crystallisation of the soap, in which the impurity forms +the colour. + +_Blue and Grey Mottled Soaps._--These are silicated or liquored soaps in +which the natural mottling, due to the impure materials used in the +early days of soap-making, is imitated by artificial mottling, and are, +consequently, entirely different to curd mottled soaps. + +The materials employed in making mottled soap comprise bleached palm +oil, tallow, bone fat, cocoa-nut oil, palm-kernel oil, cotton-seed oil, +and, in some instances, rosin. + +The choice of a charge will naturally depend upon the cost; the property +of absorbing a large amount of liquor, which is characteristic of soaps +made from cocoa-nut oil and palm-kernel oil, is taken advantage of, as +are also the physical properties of the various fats and oils, with a +view to the crystallisation of the resultant soap and the development of +the mottle. The fat is saponified, grained and boiled on strength, as +previously described. After withdrawing the half-spent lye, the soap is +just closed by boiling with water, and is then ready for the silicate or +other saline additions. + +Soap intended to be liquored with silicate of soda should be distinctly +strong in free alkali; the crystalline nature of the soap is increased +thereby, and the mottled effect intensified. Some makers, however, fit +the soap coarsely and allow a nigre to deposit; then, after removing the +nigre, or transferring the settled soap to another copper, containing +scraps of mottled soap, get the soap into a condition for mottling, and +add the silicate of soda solution. To every 1 cwt. of soap, 28 lb. of +silicate of soda solution, 32-1/2° Tw. (20° B.) is added, whilst +boiling; the strength of the silicate solution, however, will depend +upon the proportion of cocoa-nut oil and palm-kernel oil present in the +charge. Many soap-makers use 20° Tw. (13° B.) (cold) silicate solution, +whilst others prefer 140° Tw. (59.5° B.), with the gradual addition of +water to the soap, kept boiling, until the product is in the correct +mottling condition, and others, again, use bleach liquor, soda crystals, +pearl ash, and salt, together with silicate solution. + +Considerable skill and experience is necessary to discern when the soap +acquires the correct mottling state. It should drop off the spatula in +large thick flakes, take considerable time to set, and the surface +should not be glossy. + +When this mottling condition has been obtained, the colouring matter, +which would be ultramarine for the blue mottled and manganese dioxide +for the grey mottled soap (3-4 lb. ultramarine or 1-3 lb. manganese +dioxide being sufficient for 1 ton of soap), is mixed with a little +water and added to the boiling soap--the boiling is continued until all +is thoroughly amalgamated, and when the steam is shut off the contents +of the pan are ready for cleansing. + +Mottled soap is run into wooden frames, which, when full, are covered +over and allowed to cool very gradually. On cooling slowly, large +crystals are produced which result in a distinct bold mottle; if the +cooling is too rapid, a small crystal is obtained and the mottle is not +distributed, resulting in either a small mottle, or no mottle at all, +and merely a general coloration. In fact, the entire art of mottling +soap consists in properly balancing the saline solutions and colouring +matter, so that the latter is properly distributed throughout the soap, +and does not either separate in coloured masses at the bottom of the +frame, or uniformly colour the whole mass. + +A sample of the soap should test 45 per cent. fatty acids, and the +amount of salt would range from 1/2 to 1 per cent. + +Some of the English mottled soaps, especially those made from materials +which give a yellow-coloured ground, are bleached by soaking in brine, +or pickling in brine containing 2 per cent. of bleach liquor. The +resultant soap has a white ground and is firm. The bleach liquor may be +made by mixing 1 cwt. bleaching powder with 10 cwts. of soda ash +solution (15° Tw., 10° B.), allowing to settle, and using the clear +liquid, or by mixing 2 parts soda ash solution with 1 part of bleaching +powder solution, both solutions being 30° Tw. (18.8° B.). + +_Milling-base._--The materials generally used are tallows and cocoa-nut +oils of the finest quality. The tallow is thoroughly saponified first, +and the graining is performed by the aid of caustic soda lye in +preference to salt. The half-spent lyes are withdrawn, and the cocoa-nut +oil added to the pan. This is saponified, and when the saponification is +complete, "boiling-on-strength" is proceeded with. Special care should +be devoted to the "boiling-on-strength" operation--its value in good +soap-making cannot be over-rated--and perfect saponification must be +ensured. The half-spent lyes are allowed to deposit during the night, +and the soap must be carefully examined next morning to ascertain if any +alkali has been absorbed. If the caustic taste is permanent the +strengthening operation is complete, but should any caustic have been +absorbed, further addition of alkali must be made and the boiling +continued. These remarks apply equally to all soaps. + +The soap, when ready, is fitted. + +Bleached palm oil, olive oil, castor oil and lard are also employed in +the production of special milling soap bases, a palm oil soap being +specially suitable for the production of a violet-scented toilet soap. + +_Yellow Household Soaps._ (_a_) _Bar Soaps._--These are made from tallow +with an admixture of from 15-25 per cent. rosin. The best quality is +known in the South and West of England as Primrose Soap, but is +designated in the North of England by such names as Golden Pale, +Imperial Pale, Gold Medal Pale, etc. Tallow alone produces a very hard +soap of inferior lathering qualities; but rosin combines with alkali to +form a soft body, which, although not a soap in the strict sense of the +term, is readily soluble in water, and in admixture with the durable +tallow soap renders it more soluble in water and thereby increases its +lathering properties. + +The rosin may be added to the soap-pan after a previous partial +saponification with soda ash, and removal of colouring matter, and +finally saponified with caustic soda lye, or, as is more generally +adopted, as a rosin change. The pan is opened with caustic soda lye and +saturation of the rosin takes place rapidly; when completely saponified +it is grained with salt, and the coloured lye allowed to deposit and +finally withdrawn. + +The four operations already detailed apply to this soap. + +Cheaper pale soaps may be made from lower grades of tallow and rosin and +are generally silicated. + +(_b_) _Tablet or Washer Type._--A demand has arisen for soap of free +lathering qualities, which has become very popular for general household +use. This soap is usually made from a mixture of cotton-seed oil, +tallow, and cocoa-nut oil, with a varying amount of rosin. The tallow +yields firmness and durability whilst the other constituents all assist +in the more ready production of a copious lather. + +As to what amount of rosin can be used to yield a finished soap of +sufficient body and satisfactory colour, this naturally depends upon the +grade of raw material at the soap-makers' disposal. Those fats and oils +which yield firm soaps, will, of course, allow a greater proportion of +rosin to be incorporated with them than materials producing soaps of +less body. Rosin imparts softness to a soap, and also colour. + +This is a fitted soap and full details of manufacture have already been +given. + +Cheaper soaps are produced from lower grade materials hardened with +alkaline solutions. + +_Resting of Pans and Settling of Soap._--The fitted soap is allowed to +settle from four to six days. The period allowed for resting is +influenced, however, not only by the size of the boil, and the season, +but also by the composition of the soap, for if the base has been made +from firm stock it is liable to cool quicker than a soap produced from +soft-bodied materials. + +On subsidence, the contents of the pan will have divided into the +following:-- + +First. On top, a thin crust of soap, with perhaps a little light +coloured fob, which is returned to the pan after the removal of the good +soap. + +Second. The good settled soap, testing 62-63 per cent. fatty acids. The +subject of removing and treatment of this layer is fully dealt with in +the next chapter. + +Third. A layer of darker weak soap, termed "nigre," which on an average +tests 33 per cent. fatty acids, and, according to the particular fit +employed, will amount to from 15-20 per cent. of the total quantity of +soap in the pan. + +The quantity of nigre may vary not only with the amount of water added +during finishing, but is also influenced by the amount of caustic alkali +remaining in the soap paste prior to fitting. If the free caustic +alkali-content is high, the soap will require a large amount of water to +attain the desired fit. This water renders the caustic into a lye +sufficiently weak to dissolve a quantity of soap, consequently, as the +"nigre" is a weak solution of soap together with any excess of alkali +(caustic or carbonate) and salt which gravitates during the settling, +the quantity is increased. + +Fourth. A solution containing alkaline salts, mostly carbonates and +chlorides, with a little caustic. + +The amount of the layer is very variable, and doubtless, under certain +physical conditions, this liquor has separated from the nigre. + +_Utilisation of Nigres._--The nigres are boiled and the liquor separated +by graining with salt. Nigre may be utilised in various ways. + +(1) It may be used several times with new materials. This particularly +refers to soaps of the "Washer" type. The colour of the nigre will +determine the number of times it can be employed. + +(2) It may be incorporated with a soap of a lower grade than the one +from which it was obtained. In this case a system is generally adopted; +for example, soap of the best quality is made in a clean pan, the nigre +remaining is worked up with fresh material for soap of the next quality, +the nigre from that boil, in its turn, is admixed with a charge to +produce a batch of third quality, and the deposited nigre from this is +again used for a fourth quality soap--the nigre obtained from this +latter boil would probably be transferred into the cheapened "washer" or +perhaps if it was dark in colour into the brown soap-pan. + +(3) The nigre may be fitted and produce a soap similar to the original +soap from which it was deposited. It is advisable to saponify a little +fat with it. + +(4) Nigres from several boils of the same kind of soap can be collected, +boiled, and fitted. The settled portion may be incorporated with a new +charging to keep the resultant soap uniform in colour--unless this is +done, the difference in colour between boils from new materials alone, +and those containing nigre, is very noticeable. The nigre settled from +this fitted nigre boil would be utilised in brown soap. + +(5) According to its colour, and consistence, a nigre may be suitable +for the production of disinfectant, or cold-water soaps. + +(6) Nigre may be bleached by treatment with a 20 per cent. solution of +stannous chloride--1 cwt. of this solution (previously heated) is +sufficient to bleach 20 tons of nigre. + +_Transparent Soaps._--The production of transparent soaps has recently +been fully studied, from a theoretical point of view, by Richardson +(_J. Amer. Chem. Soc._, 1908, pp. 414-20), who concludes that the +function of substances inducing transparency, is to produce a jelly and +retard crystallisation. + +The old-fashioned transparent soap is prepared by dissolving, previously +dried, genuine yellow soap in alcohol, and allowing the insoluble saline +impurities to be deposited and removed. The alcoholic soap solution is +then placed in a distillation apparatus, or the pan containing the +solution is attached by means of a still head to a condenser, and the +alcohol distilled, condensed and regained. The remaining liquid soap, +which may be coloured and perfumed, is run into frames and allowed to +solidify. + +The resultant mass is somewhat turbid, but after storage in a room at +95° F. (35° C.) for several months, becomes transparent. + +The formation of the transparency is sometimes assisted and hastened by +the addition of glycerine or a solution of cane-sugar. + +A patent has been granted to A. Ruch (Fr. Pat. 327,293, 1902) for the +manufacture of transparent glycerine soap by heating in a closed vessel +fatty acids together with the requisite quantity of alcoholic caustic +soda solution necessary for saponification, and cooling the resultant +soap. It is also proposed to add sugar solution. + +Cheaper qualities of transparent soaps are made by the cold process with +or without the aid of alcohol and castor oil, and with the assistance of +glycerine or cane-sugar. + +With the continual demand for cheaper production, sugar solution has +gradually, in conjunction with castor oil, which produces transparency, +superseded the use of alcohol and glycerine. + +For a small batch, 56 lb. Cochin cocoa-nut oil and 56 lb. sweet edible +tallow may be taken, melted at 130° F. (54° C.), and carefully strained +into a small steam-jacketed pan. It is imperative that the materials +should be of the highest quality and perfectly clean. Twenty-three lb. +of pure glycerine and 56 lb. of bright caustic soda solution made from +high grade caustic and having a density of 72° Tw. (38° B.) are crutched +into the fat; the alcohol, which would be 45 lb. in this example, is +then added. The whole must be most intimately incorporated, and the pan +covered and allowed to rest for one hour or one and a half hours. +Saponification should ensue. + +To produce a transparent glycerine soap with the aid of castor oil, and +with or without the use of alcohol, the following is the procedure:-- + +Cochin cocoa-nut oil, sweet edible tallow, and castor oil, of each 56 +lb. are taken, warmed to 130° F. (54° C.), and carefully strained into +the jacketed pan. If it is desired to use glycerine and cane sugar +solution, and no alcohol, the glycerine (25 lb.) is now stirred into the +fats together with the requisite (83 lb.) caustic soda solution 72° Tw. +(38° B.). If it is intended to use alcohol and sugar, and no glycerine, +the latter is replaced by 47 lb. of alcohol, and added after the +incorporation of the caustic soda lye. + +The whole being thoroughly crutched, the pan is covered and +saponification allowed to proceed for one hour or one and a half hours. +Should the saponification for some reason be retarded, a little steam +may be very cautiously admitted to the jacket of the pan, the mass well +crutched until the reaction commences, and the whole allowed to rest the +specified time. + +Whilst saponification is proceeding, the "sugar solution" is prepared by +dissolving 50 lb. cane sugar in 50 lb. water, at 168° F. (76° C.), to +which may be added 5 lb. soda crystals, and any necessary colouring +matter. The water used for this solution should be as soft as possible, +as hard water is liable to produce opaque streaks of lime soap. + +It is absolutely necessary before proceeding further to ensure that +saponification is complete. A greasy, soft feel and the presence of +"strength" (caustic) would denote incomplete saponification--this can +only be remedied by further heating and crutching. Deficiency of caustic +alkali should also be avoided, and, if more lye is required, great care +must be exercised in its addition. + +Saponification being completed, the sugar solution is carefully and +gradually crutched into the soap; when the contents of the pan have +become a homogeneous and syrupy mass, the crutching is discontinued, and +the pan is covered for one hour. The heat of the soap in the pan should +not exceed 170° F. (77° C.). + +Having rested the necessary period, the soap will have a slight froth on +the surface, but will be clear underneath and appear dark. Samples may +now be withdrawn, cooled, and examined prior to framing. If the process +has been successfully performed the soap will be firm and transparent, +of uniform colour, and possess only a faintly alkaline taste. + +If the sample be firm but opaque, more sugar solution is required; this +should be added very carefully whilst crutching, an excess being +specially guarded against. If the sample be soft, although transparent, +and the alkaline taste not too pronounced, the soap evidently contains +an excess of water, which may be remedied by the addition of a small +quantity of soda ash; too much soda ash (carbonates) must be avoided, +lest it should produce efflorescence. + +Having examined the soap and found it to be correct, or having remedied +its defects, the soap in the pan is allowed to cool to 145° F. (63° C.) +and perfume added. The soap is now quickly filled into narrow frames and +allowed to cool rapidly. + +The blocks of soap should not be stripped until quite cold throughout, +and they should be allowed to stand open for a while before slabbing. +When freshly cut into tablets, the soap may appear somewhat turbid, but +the brightness comes with the exposure it will receive prior to stamping +and wrapping. + +_Saponifying Mineral Oil._--This sounds somewhat incongruous, as mineral +oil is entirely unsaponifiable. Most of the suggestions for this purpose +consist of the incorporation of mineral oil, or mineral oil emulsified +by aid of Quillaia bark, with a cocoa-nut oil soap, and in all these +instances the hydrocarbon merely exists in suspension. + +G. Reale (Fr. Pat. 321,510, 1902), however, proposes to heat mineral oil +together with spermaceti and strong alkali, and states that he +transforms the hydrocarbons into alcohols, and these, absorbing oxygen, +become fatty acids, which are converted into soap by means of the +alkali. + +In this connection may be quoted the interesting work of Zelinsky +(_Russ. Phys. Chem. Ges. Zeits. Angew. Chem._, 1903, 37). He obtained +substances, by acting with carbon dioxide upon magnesia compounds of +chlorinated fractions of petroleum, which when decomposed by dilute +sulphuric acid, yielded various organic acids. One of these acids on +heating with glycerine formed tri-octin, which had the properties of a +fat. + +Dr. Engler, in confirmation of the theory of the animal origin of some +petroleums, obtained what might be described as petroleum (for it +contained almost all the hydrocarbons present in the natural mineral +oil) by distilling animal fats and oils under pressure. + +_Electrical Production of Soap._--Attempts have been made to produce +soap electrically by Messrs. Nodon, Brettonneau and Shee (Eng. Pat. +22,129, 1897), and also by Messrs. Merry and Noble (Eng. Pat. 2,372, +1900). + +In the former patent, a mixture of soda-lye and fat is agitated by +electricity at a temperature of 194°-212° F. (90°-100° C.), while in the +latter caustic alkali is electrolytically produced from brine, and +deposited on wire-netting in the presence of fat, which is thereby +saponified. + + + + +CHAPTER VI. + +TREATMENT OF SETTLED SOAP. + + _Cleansing--Crutching--Liquoring of + Soaps--Filling--Neutralising, Colouring and + Perfuming--Disinfectant Soaps--Framing--Slabbing--Barring--Open + and Close Piling--Drying--Stamping--Cooling._ + + +_Cleansing._--After completion of saponification, and allowing the +contents of the pan to settle into the various layers, as described in +the preceding chapter, the actual soap, forming the second layer, is now +transferred to the frames, this being generally termed "cleansing" the +soap. The thin crust or layer at the top of the pan is gently removed, +and the soap may be either ladled out and conveyed to the frames, or +withdrawn by the aid of a pump from above the nigre through a skimmer +(Fig. 1), and pipe, attached by means of a swivel joint (Fig. 2) (which +allows the skimmer pipe to be raised or lowered at will by means of a +winch, Fig. 3), to a pipe fitted in the side of the pan as fully shown +in Fig. 4, or the removal may be performed by gravitation through some +mechanical device from the side of the copper. + +[Illustration: FIG. 1.--Skimmer, with flange for attachment to +skimmer-pipe.] + +Every precaution is taken to avoid the presence of nigre in the soap +being cleansed. + +[Illustration: FIG. 2.--Swivel-joint.] + +The temperature at which soap may be cleansed depends on the particular +grade--soaps requiring to be liquored should not be cleansed too hot or +a separation will take place, 150° F. (66° C.) may be taken as a +suitable temperature for this class of soap; in the case of firm soaps, +such as milling base, where cooling is liable to take place in the pan +(and thus affect the yield), the temperature may be 165°-170° F. +(74°-77° C.). This latter class of soap is generally run direct to the +frames and crutched by hand, or, to save manual labour, it may be run +into a power-driven crutching pan (neutralising material being added if +necessary) and stirred a few times before framing. + +[Illustration: FIG. 3.--Winch.] + +[Illustration: FIG. 4.--Soap-boiling pan, showing skimmer pipe, swivel +and winch.] + +[Illustration: FIG. 5.--Hand crutch.] + +[Illustration: FIG. 6.--Mechanical crutcher.] + +_Crutching._--This consists of stirring the hot soap in the frames by +hand crutches (Fig. 5) until the temperature is sufficiently lowered and +the soap begins to assume a "ropiness". Crutching may also be performed +mechanically. There are various types of mechanical crutchers, +stationary and travelling. They may be cylindrical pans, jacketed or +otherwise, in the centre of which is rotated an agitator, consisting of +a vertical or horizontal shaft carrying several blades (Fig. 6) or the +agitator may take the form of an Archimedean screw working in a cylinder +(Fig. 7). + +[Illustration: FIG. 7.--Mechanical crutcher.] + +The kind of soap to be crutched, whether thin or stiff, will determine +the most suitable type for the purpose. The former class includes +"washer" soap which is generally neutralised, and coloured and perfumed, +if necessary, in these crutching pans, and in that case they are merely +used for mixing the liquids with the hot soap prior to its passage along +wooden spouts (Fig. 8) provided with outlets over the frames, in which +the crutching is continued by hand. In the case of stiff soaps requiring +complete incorporation of liquor, the screw type is preferable, the soap +being forced upwards by the screw, and descending between the cylinder +and the sides of the pan, while the reverse action can also be brought +into play. The completion of crutching is indicated by the smoothness +and stiffness of the soap when moved with a trowel, and a portion taken +out at this point and cooled should present a rounded appearance. When +well mixed the resultant product is emptied directly into wheel-frames +placed underneath the outlet of the pan. It is important that the blades +or worm of the agitating gear be covered with soap to avoid the +occlusion of air and to prevent the soap becoming soft and spongy. + +[Illustration: FIG. 8.--Wooden soap spout.] + +_Liquoring of Soaps._--This consists of the addition of various alkaline +solutions to soap to produce different qualities, and is best performed +in the crutching machines, although it is in some instances carried out +in the frames. In the history of soap-making a large number and variety +of substances have been suggested for the purpose of accomplishing some +real or supposed desirable effect when added to soap. Many of these have +had only a very short existence, and others have gradually fallen out of +use. + +Amongst the more practical additions most frequently adopted may be +mentioned carbonate of soda, silicate of soda, and pearl ash (impure +carbonate of potash). The carbonate of soda may be used in the form of +"soda crystals," which, containing 62.9 per cent. of water, dissolves in +its own water of crystallisation on heating, and is in that manner added +to the hot soap. In the case of weak-bodied soap, this addition gives +firmness and tends to increase the detergent qualities. + +The soda carbonate may also be added to soap as a solution of soda ash +(58° alkali) either concentrated, 62° Tw. (34° B.), or of various +strengths from 25° Tw. (16° B.) upwards. This solution stiffens and +hardens soap, and the addition, which must not be excessive, or +efflorescence will occur, is generally made at a temperature of 140° F. +(60° C.). Care should always be taken in the choice of solutions for +liquoring. Strong soda ash solution with a firm soap will result in a +brittle product, whereas the texture of a weak soap would be greatly +improved by such addition. + +A slight addition of a weak solution of pearl ash, 4°-8° Tw. (2.7-5.4° +B.), improves the appearance of many soaps intended for household +purposes. + +For yellow soaps, containing a low percentage of fatty acids, solutions +of silicate of soda of varying strengths are generally used. + +It is always advisable to have a test sample made with the soap to +ascertain what proportion and what strength of sodium silicate solution +is best suited for the grade of soap it is desired to produce. It is +important that the soap to be "silicated" should be distinctly alkaline +(_i.e._, have a distinct caustic taste), or the resultant soap is liable +to become like stone with age. The alkaline silicate of soda (140° Tw., +59.5° B.) is the quality most convenient for yellow soaps; this may be +diluted to the desired gravity by boiling with water. For a reduction of +3-4 per cent. fatty acids content, a solution of 6° Tw. (4° B.) +(boiling) is most suitable, and if the reduction desired is greater, the +density of the silicate solution should be increased; for example, to +effect a reduction of 20 per cent. fatty acids content, a solution of +18° Tw. (12° B.) (boiling) would probably be found to answer. + +In some instances 140° Tw. (59.5° B.) silicate may be added; experiment +alone will demonstrate the amount which can be satisfactorily +incorporated without the soap becoming "open," but 1/10 of the quantity +of soap taken is practically a limit, and it will be found that the +temperature should be low; the same quantity of silicate at different +temperatures does not produce the same result. Various other strengths +of sodium silicate are employed, depending upon the composition and body +of the soap base--neutral silicate 75° Tw. (39.4° B.) also finds favour +with some soap-makers. Mixtures of soda crystals or soda ash solution +with silicate of soda solution are used for a certain grade of soap, +which is crutched until smooth and stiff. Glauber's salt (sodium +sulphate) produces a good smooth surface when added to soap, but, owing +to its tendency to effloresce more quickly than soda carbonate, it is +not so much used as formerly. + +Common salt sometimes forms an ingredient in liquoring mixtures. +Potassium chloride and potassium silicate find a limited use for +intermixing with soft soaps. + +It will be readily understood that hard and fast rules cannot be laid +down for "liquoring" soap, and the correct solution to be employed can +only be ascertained by experiment and experience, but the above +suggestions will prove useful as a guide towards good results. A smooth, +firm soap of clear, bright, glossy appearance is what should be aimed +at. + +_Filling._--Some low-grade soaps contain filling, which serves no useful +purpose beyond the addition of weight. Talc is the most frequently used +article of this description. It consists of hydrated silicate of +magnesium and, when finely ground, is white and greasy to the touch. The +addition of this substance to the hot soap is made by suspending it in +silicate of soda solution. + +Whatever filling material is used, it is important that the appearance +of the soap should not be materially altered. + +_Neutralising, Colouring and Perfuming._--The free caustic alkali in +soap, intended for toilet or laundry purposes, is usually neutralised +during the cleansing, although some soap manufacturers prefer to +accomplish this during the milling operation. Various materials have +been recommended for the purpose, those in most general use being sodium +bicarbonate, boric acid, cocoa-nut oil, stearic acid, and oleic acid. + +The best method is the addition of an exact quantity of sodium +bicarbonate (acid sodium carbonate), which converts the caustic alkali +into carbonate. The reaction may be expressed by the equation:-- + + NaOH + NaHCO_{3} = Na_{2}CO_{3} + H_{2}O + Caustic soda Bicarbonate of soda Carbonate of soda Water + +Boric acid in aqueous or glycerine solutions, and borax (biborate of +soda) are sometimes used, but care is necessary in employing these +substances, as any excess is liable to decompose the soap. + +The addition of cocoa-nut oil is unsatisfactory, the great objection +being that complete saponification is difficult to ensure, and, further, +there is always the liability of rancidity developing. Stearic and oleic +acids are more suitable for the purpose, but oleic acid has the +disadvantage that oleates are very liable to go rancid. + +A large number of other substances have been proposed, and in many +instances patented, for neutralising the free caustic alkali. Among +these may be mentioned--Alder Wright's method of using an ammoniacal +salt, the acid radicle of which neutralises the caustic alkali, ammonia +being liberated; the use of sodium and potassium bibasic phosphate (Eng. +Pat. 25,357, 1899); a substance formed by treating albumen with formalin +(Eng. Pat., 8,582, 1900); wheat glutenin "albuminoses" (albumen after +acid or alkaline treatment); malt extract; and egg, milk, or vegetable +albumen. + +The colouring matter used may be of either vegetable or coal-tar origin, +and is dissolved in the most suitable medium (lye, water, or fat). The +older types of colouring matter--such as cadmium yellow, ochres, +vermilion, umbers--have been superseded. + +In the production of washer household soaps, a small quantity of perfume +is sometimes added. + +_Disinfectant Soaps._--To the soap base, which must be strong to taste, +is added from 3 to 4 per cent. of coal-tar derivatives, such as carbolic +acid, cresylic acid, creosote, naphthalene, or compounds containing +carbolic acid and its homologues. The incorporation is made in the +crutching pan, and further crutching may be given by hand in the frames. + +_Framing._--The object of framing is to allow the soap to solidify into +blocks. The frames intended for mottled soaps, which require slow +cooling, are constructed of wood, often with a well in the base to allow +excess of lye to accumulate--for other soaps, iron frames are in general +use. The frame manufactured by H. D. Morgan of Liverpool is shown in +Fig. 9. + +As soon as the frame is filled, or as soon as the crutching in the frame +is finished, the soap is smoothed by means of a trowel, leaving in the +centre a heap which slopes towards the sides. Next day the top of the +soap is straightened or flattened with a wooden mallet, this treatment +assisting in the consolidation. + +[Illustration: FIG. 9.--Soap frame.] + +[Illustration: FIG. 10.--Slabbing machine.] + +The length of time the soap should remain in frames is dependent on the +quality, quantity, and season or temperature, and varies usually from +three to seven days. When the requisite period has elapsed, the sides +and ends of the frames are removed, and there remains a solid block of +soap weighing from 10 to 15 cwt. according to the size of frame used. +The blocks, after scraping and trimming, are ready for cutting into +slabs. + +_Slabbing._--This may be done mechanically by pushing the block of soap +through a framework containing pianoforte wires fixed at equi-distances +(Fig. 10, which shows a machine designed by E. Forshaw & Son, Ltd.), or +the soap may be out by hand by pulling a looped wire through the mass +horizontally along lines previously scribed, or, for a standard sized +slab, the wire may be a fixture in a box-like arrangement, which is +passed along the top of the soap, and the distance of the wire from the +top of the box will be the thickness of the slab (Fig. 11). + +[Illustration: FIG. 11.--Banjo slabber.] + +All tallow soaps should be slabbed whilst still warm, cut into bars, and +open-piled immediately; if this type of soap is cold when slabbed its +appearance will be very much altered. + +_Barring._--The slabs are out transversely into bars by means of the +looped wire, or more usually by a machine (Fig. 12), the lower framework +of which, containing wires, is drawn through the soap placed on the +base-board; the framework is raised, and the bars fall upon the shelf, +ready for transference into piles. It has long been the custom in +England to cut bars of soap 15 inches long, and weighing 3 lb. each, or +37-1/2 bars of soap to the cwt., but in recent years a demand has arisen +for bars of so many various weights that it must be sometimes a +difficult matter to know what sizes to stock. + +In another type of barring machine, portions of the slab, previously cut +to size, are pushed against a framework carrying wires, and the bars +slide along a table ready for handling (Fig. 13). + +In cutting machines, through which "washer" household soap is being +passed, the bar is pushed at right angles through another frame +containing wires, which divides it into tablets; these may be received +upon racks and are ready for drying and stamping. It is needless to say +that the slabs and tablets are cut with a view to reducing the amount of +waste to the lowest possible limit. Such a machine, made by E. Forshaw & +Son, Ltd., is shown in Fig. 14. + +[Illustration: FIG. 12.--Barring machine.] + +[Illustration: FIG. 13.--Bar-cutting machine.] + +[Illustration: FIG. 14.--Tablet-cutting machine.] + +_Open- and Close-piling._--As remarked previously, tallow soaps should +be cut whilst warm, and the bars "open-piled," or stacked across each +other in such a way that air has free access to each bar for a day. The +bar of soap will skin or case-harden, and next day may be "close-piled," +or placed in the storage bins, where they should remain for two or three +weeks, when they will be in perfect condition for packing into boxes +ready for distribution. + +[Illustration: FIG. 15.--Soap stamp.] + +_Drying._--"Oil soaps," as soaps of the washer type are termed, do not +skin sufficiently by the open-piling treatment, and are generally +exposed on racks to a current of hot air in a drying chamber in order to +produce the skin, which prevents evaporation of water, and allows of an +impression being given by the stamp without the soap adhering to the +dies. It is of course understood that heavily liquored soaps are, as a +rule, unsuitable for the drying treatment, as the bars become unshapely, +and lose water rapidly. + +_Stamping._--Bar soaps are usually stamped by means of a hand-stamp +containing removable or fixed brass letters (Fig. 15), with a certain +brand or designation of quality and the name of the manufacturer or +vendor, and are now ready for packing into boxes. + +A very large bulk of the soap trade consists of the household quality in +tablet form, readily divided into two cakes. These are stamped in the +ordinary box moulds with two dies--top and bottom impressions--the +die-plates, being removable, allow the impressions to be changed. This +type of mould (Fig. 16) can be adjusted for the compression of tablets +of varying thickness, the box preventing the escape of soap. We are +indebted to E. Forshaw & Son, Ltd., for this illustration. + +[Illustration: FIG. 16.--Box mould.] + +The stamping machine may be worked by hand (Fig. 17) or power driven. +Where large quantities of a particular tablet have to be stamped, one of +the many automatic mechanical stampers in existence may be employed, the +tablets being conveyed to and from the dies by means of endless belts. +Such a machine is shown in the accompanying illustration (Fig. 18). + +If necessary, the soap is transferred to racks and exposed to the air, +after which it is ready for wrapping, which is generally performed by +manual labour, although in some instances automatic wrapping machines +are in use. + +Cardboard cartons are also used for encasing the wrapped tablets, the +object being that these are more conveniently handled by tradesmen and +may be advantageously used to form an attractive window display. + +_Cooling._--Many attempts have been made to shorten the time required +for the framing and finishing of soap, by cooling the liquid soap as it +leaves the pan. + +[Illustration: FIG. 17.--Soap-stamping machine, showing box mould.] + +With milling base, this is successfully accomplished in the +Cressonnières' plant, by allowing the hot soap to fall upon the +periphery of a revolving drum which can be cooled internally by means of +water. + +[Illustration: FIG. 18.--Automatic stamper.] + +In the case of household soaps, where the resultant product must be of +good appearance and have a firm texture, the difficulty is to produce a +bar fit for sale after the cooling has been performed, as soap which has +been suddenly chilled lacks the appearance of that treated in the +ordinary way. Several patents have been granted for various methods of +moulding into bars in tubes, where the hot soap is cooled by being +either surrounded by running water in a machine of similar construction +to a candle machine, or rotated through a cooling medium; and numerous +claims have been made both for mechanical appliances and for methods of +removing or discharging the bars after cooling. In many instances these +have proved unsatisfactory, owing to fracture of the crystalline +structure. Moreover, in passing through some of the devices for +solidification after chilling, the soap is churned by means of a worm or +screw, and this interferes with the firmness of the finished bar, for, +as is well known, soap which has been handled too much, does not regain +its former firmness, and its appearance is rendered unsatisfactory. + +A form of apparatus which is now giving satisfactory results is the +Leimdoerfer continuous cooler (Fig. 19). This consists of a fixed +charging hopper, A, a portable tank, B, containing tubes, and a +detachable box, C, which can be raised or lowered by means of a screw, +D. The bottom of the hopper is fitted with holes corresponding with the +cooling tubes, _e_, and closed by plugs _c_, attached to a frame _b_, +which terminates above in a screw spindle _a_, by means of which the +frame and plugs can be raised and lowered so as to permit or stop the +outflow of soap into the cooling tubes. The tubes are closed at the +bottom by slides _d_, and the box B, in which they are mounted, is +carried on a truck running on rails. The charging hopper can be +connected with the soap-pan by a pipe, and when the hopper is filled +with liquid soap the plugs _c_ are raised and the air in the box C +exhausted, thus causing the soap to descend into the cooling tubes. + +[Illustration: FIG. 19.--Leimdoerfer cooler.] + +The slides _d_ are closed, the screw D released, and the box B moved +away to make room for another. At the end of the rail track is an +ejecting device which pushes the cooled soap out of the tubes, and the +truck is run back on a side track to the machine for use over again. In +this way the apparatus can be worked continuously, the soap being +received from the cooling pipes on a suitable arrangement for transport +to the press or store room. + +A similar idea has been made the subject of a patent by Holoubek (Eng. +Pat. 24,440, 1904, Fig. 20). The soap is run into frames or moulds +having open sides, which are closed by being clamped with screws and +pressure plates between cooling tubes through which water circulates. + +[Illustration: FIG. 20.--Holoubek's cooler.] + + + + +CHAPTER VII. + +TOILET, TEXTILE AND MISCELLANEOUS SOAPS. + + _Toilet Soaps--Cold Process Soaps--Settled Boiled + Soaps--Remelted Soaps--Milled Soaps--Drying--Milling and + Incorporating Colour, Perfume, or + Medicament--Perfume--Colouring Matter--Neutralising and + Superfatting + Material--Compressing--Cutting--Stamping--Medicated + Soaps--Ether Soap--Floating Soaps--Shaving Soaps--Textile + Soaps--Soaps for Woollen, Cotton and Silk Industries--Patent + Textile Soaps--Miscellaneous Soaps._ + + +_Toilet Soaps._--By the term "toilet soap" is inferred a soap specially +adapted for toilet use by reason not only of its good detergent and +lathering qualities, but also on account of its freedom from caustic +alkali and any other ingredient likely to cause irritation or injury to +the skin. + +Toilet soaps may be simply classified according to their method of +preparation into the following four classes:-- + + (1) Cold process soaps. + (2) Settled boiled soaps. + (3) Remelted soaps. + (4) Milled soaps. + +Soaps of the first class are of comparatively trifling importance, +having been superseded by the other qualities. Details of the "cold +process" have already been given on page 46; it is only necessary to add +the desired perfume and colouring matter to the soap. + +The second class consists of good quality settled soaps, direct from the +copper, to which have been added, prior to framing, suitable perfume and +colouring matter, also, if necessary, dealkalising materials. + +The third class is represented by soaps made by the old English method +of remelting, which are often termed "perfumers'," or "little pan" +soaps. The soap-base or mixture of various kinds of soap is remelted in +a steam-jacketed pan, or pan provided with steam coils, and agitated. +The agitation must not be too vigorous or lengthy, or the soap will +become aerated. When all the soap is molten, additions of pearl ash +solution are made to give it a finer and smoother texture, render it +more transparent, and increase its lathering properties. The necessary +colour, in a soluble form, is well incorporated, and lastly the perfume. +Owing to volatilisation, much of the perfume is lost when added to hot +soap, and it is necessary to add a large quantity to get the desired +odour; hence the cheaper essential oils have to be used, so that the +perfume of this class of soap is not so delicate as that of milled +soaps, although it is quite possible to produce remelted soaps as free +from uncombined alkali as a milled toilet soap. + +Palm-oil soap often forms the basis for yellow and brown toilet soaps of +this class. The old-fashioned Brown Windsor soap was originally a curd +soap that with age and frequent remelting had acquired a brown tint by +oxidation of the fatty acids--the oftener remelted the better the +resultant soap. + +Medicaments are sometimes added to these soaps, _e.g._, camphor, borax, +coal-tar, or carbolic. Oatmeal and bran have been recommended in +combination with soap for toilet purposes, and a patent (Eng. Pat. +26,396, 1896) has been granted for the use of these substances together +with wood-fibre impregnated with boric acid. + +After cooling in small frames, the soap is slabbed, and cut into blocks, +and finally into portions suitable for stamping in a press (hand or +steam driven) with a design or lettering on each side. + +_Milled Toilet Soaps._--Practically all high-class soaps now on the +market pass through the French or milling process. This treatment, as +its name implies, was first practised by the French who introduced it to +this country, and consists briefly of (i.) drying, (ii.) milling and +incorporating colour, perfume or medicament, (iii.) compressing, and +(iv.) cutting and stamping. + +The advantages of milled soap over toilet soap produced by other methods +are that the former, containing less water and more actual soap, is more +economical in use, possesses a better appearance, and more elegant +finish, does not shrink or lose its shape, is more uniform in +composition, and essential oils and delicate perfumes may be +incorporated without fear of loss or deterioration. + +Only soap made from best quality fats is usually milled, a suitable base +being that obtained by saponifying a blend of the finest white tallow +with a proportion, not exceeding 25 per cent., of cocoa-nut oil, and +prepared as described in Chapter V. + +The first essential of a milling base is that the saponification should +be thorough and complete; if this is not ensured, rancidity is liable to +occur and a satisfactory toilet soap cannot be produced. The soap must +not be short in texture or brittle and liable to split, but of a firm +and somewhat plastic consistency. + +(i.) _Drying._--The milling-base, after solidification in the frames, +contains almost invariably from 28 to 30 per cent. of water, and this +quantity must be reduced to rather less than half before the soap can be +satisfactorily milled. Cutting the soap into bars or strips and open +piling greatly facilitates the drying, which is usually effected by +chipping the soap and exposing it on trays to a current of hot air at +95-105° F. (35-40° C.). + +There are several forms of drying chambers in which the trays of chips +are placed upon a series of racks one above another, and warm air +circulated through, and Fig. 21 shows a soap drying apparatus with fan +made by W. J. Fraser & Co., Ltd., London. + +The older method of heating the air by allowing it to pass over a pipe +or flue through which the products of combustion from a coke or coal +fire are proceeding under the floor of the drying chamber to a small +shaft, has been superseded by steam heat. The air is either drawn or +forced by means of quickly revolving fans through a cylinder placed in a +horizontal position and containing steam coils, or passed over +steam-pipes laid under the iron grating forming the floor of the +chamber. + +[Illustration: FIG. 21.--Soap-drying apparatus.] + +It will be readily understood that in the case of a bad conductor of +heat, like soap-chippings, it is difficult to evaporate moisture +without constantly moving them and exposing fresh surfaces to the +action of heat. + +In the Cressonnières' system, where the shavings of chilled soap are +dried by being carried through a heated chamber upon a series of endless +bands (the first discharging the contents on to a lower belt which +projects at the end, and is moving in the opposite direction, and so +on), this is performed by intercepting milling rollers in the system of +belts (Eng. Pat. 4,916, 1898) whereby the surfaces exposed to the drying +are altered, and it is claimed that the formation of hardened crust is +prevented. + +In the ordinary methods of drying, the chips are frequently moved by +hand to assist uniform evaporation. + +The degree of saturation of the air with moisture must be taken into +consideration in regulating the temperature and flow of air through the +drying chamber, and for this purpose the use of a hygrometer is +advantageous. + +It is very important that the correct amount of moisture should be left +in the soap, not too much, nor too little; the exact point can only be +determined by judgment and experience, and depends to a considerable +extent upon the nature of the soap, and also on the amount of perfume or +medicament to be added, but speaking generally, a range of 11 to 14 per +cent. gives good results. If the soap contains less than this amount it +is liable to crumble during the milling, will not compress +satisfactorily, and the finished tablet may have a tendency to crack and +contain gritty particles so objectionable in use. If, on the other hand, +the soap is left too moist, it is apt to stick to the rollers and mill +with difficulty, and during compression the surface assumes a blistered +and sticky appearance. + +(ii.) _Milling and Incorporation of Colour, Perfume or Medicament._--The +object of milling is to render the soap perfectly homogeneous, and to +reduce it to a state in which colour, perfume, or any necessary +neutralising material or other substance may be thoroughly incorporated. +The milling machine consists of smooth granite rollers, fitted with +suitable gearing and working in an iron framework (Fig. 22). The rollers +are connected in such a manner that they rotate at different speeds, and +this increases the efficiency of the milling, and ensures that the +action of the rollers is one of rubbing rather than crushing. + +By means of suitably arranged screws the pressure of the rollers on one +another can be adjusted to give the issuing soap any desired thickness; +care should be taken that the sheets of soap are not unnecessarily thick +or the colour and odour will not be uniform. + +The soap, in the form of chips, is introduced on to the rollers through +a hopper, and after one passage through the mill, from bottom to top, +one of the serrated knife edges is applied and the ribbons of the soap +are delivered into the top of the hopper where the colour, perfume, and +any other desired admixture is added, and the milling operation repeated +three or four times. When the incorporation is complete the other +scraper is fixed against the top roller and the soap ribbon passed into +the receptacle from which it is conveyed to the compressor. A better +plan, however, especially in the case of the best grade soaps, where the +perfumes added are necessarily more delicate and costly, is to make the +addition of the perfume when the colour has been thoroughly mixed +throughout the mass. Another method is to mill once and transfer the +mass to a rotary mixing machine, fitted with internal blades, of a +peculiar form, which revolve in opposite directions one within the other +as the mixer is rotated. The perfume, colouring matter, etc., are added +and the mixer closed and set in motion, when, after a short time, the +soap is reduced to a fine granular condition, with the colour and +perfume evenly distributed throughout the whole. By the use of such +machines, the loss of perfume by evaporation, which during milling is +quite appreciable, is reduced to a minimum, and the delicacy of the +aroma is preserved unimpaired. + +[Illustration: FIG. 22.--Milling machine.] + +Prolonged milling, especially with a suitable soap base, tends to +produce a semi-transparent appearance, which is admired by some, but the +increased cost of production by the repeated milling is not accompanied +by any real improvement in the soap. + +_Perfume._--The materials used in perfuming soap will be dealt with +fully in the next chapter. The quantity necessary to be added varies +considerably with the nature of the essential oils, and also the price +at which the soap is intended to be sold. In the cheaper grades of +milled soaps the quantity will range from 10-30 fluid ozs. per cwt., and +but rarely exceeds 18-20 ozs., whereas in more costly soaps as much as +40-50 fluid ozs. are sometimes added to the cwt. + +_Colouring Matter._--During recent years an outcry has been made against +highly coloured soaps, and the highest class soaps have been +manufactured either colourless or at the most with only a very delicate +tint. It is obvious that a white soap guarantees the use of only the +highest grade oils and fats, and excludes the introduction of any rosin, +and, so far, the desire for a white soap is doubtless justified. Many +perfumes, however, tend to quickly discolour a soap, hence the advantage +of giving it a slight tint. For this purpose a vegetable colouring +matter is preferable, and chlorophyll is very suitable. + +[Illustration: FIG. 23.--Compressor.] + +A demand still exists for brightly coloured soaps, and this is usually +met by the use of coal-tar dyes. The quantity required is of course +extremely small, so that no harm or disagreeable result could possibly +arise from their use. + +_Neutralising and Superfatting Material._--If desired, the final +neutralisation of free alkali can be carried out during the milling +process, any superfatting material being added at the same time. The +chief neutralising reagents have already been mentioned in Chapter VI. + +With regard to superfatting material, the quantity of this should be +very small, not exceeding 6-8 ozs. per cwt: The most suitable materials +are vaseline, lanoline, or spermaceti. + +[Illustration: FIG. 24--Hand soap-stamping press.] + +(iii.) _Compressing._--The next stage is the compression and binding of +the soap ribbons into a solid bar suitable for stamping, and the plant +used (Fig. 23) for this purpose is substantially the same in all +factories. The soap is fed through a hopper into a strong metal +conical-shaped tube like a cannon, which tapers towards the nozzle, and +in which a single or twin screw is moving, and the soap is thereby +forced through a perforated metallic disc, subjected to great pressure, +and compressed. The screws must be kept uniformly covered with shavings +during compression to obviate air bubbles in the soap. + +[Illustration: FIG. 25.--Screw press.] + +The soap finally emerges through the nozzle (to which is attached a +cutter of suitable shape and size according to the form it is intended +the final tablet to take) as a long, polished, solid bar, which is cut +with a knife or wire into lengths of 2 or 3 feet, and if of satisfactory +appearance, is ready for cutting and stamping. The nozzle of the plodder +is heated by means of a Bunsen burner to about 120° or 130° F. (49°-55° +C.) to allow the soap to be easily forced out, and this also imparts a +good gloss and finish to the ejected bar--if the nozzle is too hot, +however, the soap will be blistered, whereas insufficient heat will +result in streaky soap of a poor and dull appearance. + +(iv.) _Cutting and Stamping._--In cutting the soap into sections for +stamping, the cutter should shape it somewhat similar to the required +finished tablet. + +Many manufacturers cut the soap into sections having concave ends, and +in stamping, the corners are forced into the concavity, with the result +that unsightly markings are produced at each end of the tablet. It is +preferable to have a cutter with convex ends, and if the stamping is to +be done in a pin mould the shape should be a trifle larger than the +exact size of the desired tablet. + +[Illustration: FIG. 26--Pin mould.] + +The stamping may be performed by a hand stamper (Fig. 24), a screw press +(Fig. 25), or by a steam stamper. The screw press works very +satisfactorily for toilet soaps. + +There are two kinds of moulds in use for milled soaps:-- + +(_a_) _Pin Moulds_ in which tablets of one size and shape only can be +produced (Fig. 25). The edges of the mould meet very exactly, the upper +part of the die carries two pins attached to the shoulder, and these are +received into two holes in the shoulder of the bottom plate. The +superfluous soap is forced out as the dies meet. + +(_b_) _Band or Collar Moulds._--In this form (Fig, 27) the mould may be +adjusted to stamp various sized tablets, say from 2 ozs. to 5-1/3 ozs. +and different impressions given by means of removable die plates. The +band or collar prevents the soap squeezing out sideways. We are indebted +to R. Forehaw & Son, Ltd., for the loan of this illustration. + +It is usual to moisten the soap or mould with a dilute solution of +glycerine if it should have a tendency to stick to the die plates. + +The soap is then ready for final trimming, wrapping, and boxing. + +[Illustration: FIG. 27--Band Mould.] + + +MEDICATED SOAPS. + +The inherent cleansing power of soap renders it invaluable in combating +disease, while it also has distinct germicidal properties, a 2 per cent. +solution proving fatal to B. coli communis in less than six hours, and +even a 1 per cent. solution having a marked action on germs in fifteen +minutes. + +Many makers, however, seek more or less successfully to still further +increase the value of soap in this direction by the incorporation of +various drugs and chemicals; and the number of medicated soaps on the +market is now very large. Such soaps may consist of either hard or soft +soaps to which certain medicaments have been added, and can be roughly +divided into two classes, (_a_) those which contain a specific for +various definite diseases, the intention being that the remedy should be +absorbed by the pores of the skin and thus penetrate the system, and +(_b_) those impregnated with chemicals intended to act as antiseptics or +germicides, or, generally, as disinfectants. + +The preparation of medicinal soaps appears to have been first taken up +in a scientific manner by Unna of Hamburg in 1886, who advocated the use +of soap in preference to plasters as a vehicle for the application of +certain remedies. + +Theoretically, he considered a soap-stock made entirely from beef tallow +the most suitable for the purpose, but in practice found that the best +results were obtained by using a superfatted soap made from a blend of +one part of olive oil with eight parts of beef tallow, saponified with a +mixture of two parts of soda to one part of potash, sufficient fat being +employed to leave an excess of 3 or 4 per cent. unsaponified. Recent +researches have shown, however, that even if a superfatted soap-base is +beneficial for the preparation of toilet soaps (a point which is open to +doubt), it is quite inadmissible for the manufacture of germicidal and +disinfectant soaps, the bactericidal efficiency of which is much +restricted by the presence of free fat. + +Many of the medicaments added to soaps require special methods of +incorporation therein, as they otherwise react with the soap and +decompose it, forming comparatively inert compounds. This applies +particularly to salts of mercury, such as _corrosive sublimate_ or +mercuric chloride, and _biniodide of mercury_, both of which have very +considerable germicidal power, and are consequently frequently added to +soaps. If simply mixed with the soap in the mill, reaction very quickly +takes place between the mercury salt and the soap, with formation of the +insoluble mercury compounds of the fatty acids, a change which can be +readily seen to occur in such a soap by the rapid development on +keeping, of a dull slaty-green appearance. Numerous processes have been +suggested, and in some cases patented, to overcome this difficulty. In +the case of corrosive sublimate, Geissler suggested that the soap to +which this reagent is to be added should contain an excess of fatty +acids, and would thereby be rendered stable. This salt has also been +incorporated with milled soap in a dry state in conjunction with +ammonio-mercuric chloride, [beta]-naphthol, methyl salicylate, and +eucalyptol. It is claimed that these bodies are present in an unchanged +condition, and become active when the soap is added to water as in +washing. Ehrhardt (Eng. Pat. 2,407, 1898) patented a method of making +antiseptic mercury soap by using mercury albuminate--a combination of +mercuric chloride and casein, which is soluble in alkali, and added to +the soap in an alkaline solution. + +With biniodide of mercury the interaction can be readily obviated by +adding to the biniodide of mercury an equal weight of potassium iodide. +This process, devised and patented by J. Thomson in 1886, has been +worked since that time with extremely satisfactory results. Strengths of +1/2, 1, and 3 per cent. biniodide are sold, but owing to the readiness +with which it is absorbed by the skin a soap containing more than 1/2 +per cent. should only be used under medical advice. + +A similar combination of _bromide of mercury_ with potassium, sodium, or +ammonium bromide has recently been patented by Cooke for admixture with +liquid, hard, or soft soaps. + +_Zinc and other Metallic Salts._--At various times salts of metals other +than mercury have been added to soap, but, owing to their insolubility +in water, their efficiency as medicaments is very trifling or nil. +Compounds have been formed of metallic oxides and other salts with oleic +said, and mixtures made with vaseline and lanoline, and incorporated +with soap, but they have not met with much success. + +Another chemical commonly added to soap is _Borax_. In view of its +alkaline reaction to litmus, turning red litmus blue, this salt is no +doubt generally regarded as alkaline, and, as such, without action on +soap. On the contrary, however, it is an acid salt containing an excess +of boric acid over the soda present, hence when it is added to soap, +fatty acids are necessarily liberated, causing the soap to quickly +become rancid. As a remedy for this it has been proposed to add +sufficient alkali to convert the borax into neutral mono-borate of soda +which is then added to the soap. This process is patented and the name +"Kastilis" has been given to the neutral salt. The incorporation of +borax with the addition of gum tragasol forms the subject of two patents +(Eng. Pats. 4,415, 1904; and 25,425, 1905); increased detergent and +lasting properties are claimed for the soap. Another patented process +(Eng. Pat. 17,218, 1904) consists of coating the borax with a protective +layer of fat or wax before adding to the soap with the idea that +reaction will not take place until required. _Boric acid_ possesses the +defects of borax in a greater degree, and would, of course, simply form +sodium borate with liberation of fatty acids, so should never be added +to a neutral soap. + +_Salicylic Acid_ is often recommended for certain skin diseases, and +here again the addition of the acid to soap under ordinary conditions +results in the formation of sodium salicylate and free fatty acids. + +To overcome this a process has recently been patented for rubbing the +acid up with vaseline before addition to soap, but the simplest way +appears to be to add the soda salt of the acid to soap. + +Amongst the more common milled medicated toilet soaps may be mentioned, +in addition to the above:-- + +_Birch Tar Soap_, containing 5 or 10 per cent. birch tar, which has a +characteristic pungent odour and is recommended as a remedy for eczema +and psoriasis. + +_Carbolic Soap._--A toilet soap should not contain more than 3 per cent. +of pure phenol, for with larger quantities irritation is likely to be +experienced by susceptible skins. + +_Coal Tar._--These soaps contain, in addition to carbolic acid and its +homologues, naphthalene and other hydrocarbons derived from coal, +naphthol, bases, etc. Various blends of different fractions of coal tar +are used, but the most valuable constituents from a disinfectant point +of view are undoubtedly the phenols, or tar acids, though in this case +as with carbolic and cresylic soaps, the amount of phenols should not +exceed 3 per cent. in a toilet soap. An excess of naphthalene should +also be avoided, since, on account of its strong odour, soaps containing +much of it are unpopular. The odour of coal tar is considerably modified +by and blends well with a perfume containing oils of cassia, lavender, +spike, and red thyme. + +_Formaldehyde._--This substance is one of the most powerful +disinfectants known, and it may be readily introduced into soap without +undergoing any decomposition, by milling in 2-3 per cent. of formalin, a +40 per cent. aqueous solution of formaldehyde, which is a gas. White +soaps containing this chemical retain their whiteness almost +indefinitely. + +New combinations of formaldehyde with other bodies are constantly being +brought forward as disinfectants. Among others the compound resulting +from heating lanoline with formaldehyde has been patented (Eng. Pat. +7,169, 1898), and is recommended as an antiseptic medicament for +incorporation with soap. + +_Glycerine._--Nearly all soaps contain a small quantity of this body +which is not separated in the lyes. In some cases, however, a much +larger quantity is desired, up to some 6 or 8 per cent. To mill this in +requires great care, otherwise the soap tends to blister during +compression. The best way is to dry the soap somewhat further than +usual, till it contains say only 9 or 10 per cent. moisture and then +mill in the glycerine. + +_Ichthyol_ or _Ammonium-Ichthyol-Sulphonate_ is prepared by treating +with sulphuric acid, and afterwards with ammonia, the hydrocarbon oil +containing sulphur obtained by the dry distillation of the fossil +remains of fish and sea-animals, which form a bituminous mineral deposit +in Germany. This product has been admixed with soap for many years, the +quantity generally used being about 5 per cent.; the resultant soap is +possessed of a characteristic empyreumatic smell, very dark colour, and +is recommended for rosacea and various skin diseases, and also as an +anti-rheumatic. Ichthyol has somewhat changed its character during +recent years, being now almost completely soluble in water, and stronger +in odour than formerly. + +_Iodine._--A soap containing iodine is sometimes used in scrofulous skin +diseases. It should contain some 3 per cent. iodine, while potassium +iodide should also be added to render the iodine soluble. + +_Lysol._--This name is applied to a soap solution of cresol, "Lysol +Soap" being simply another form of coal-tar soap. The usual strength is +10 per cent. lysol, and constitutes a patented article (Fr. Pat. +359,061, 1905). + +_Naphthol._--[beta]-Naphthol, also a coal-tar derivative, is a good +germicide, and, incorporated in soap to the extent of 3 per cent. +together with sulphur, is recommended for scabies, eczema and many other +cutaneous affections. + +_Sulphur._--Since sulphur is insoluble in water, its action when used in +conjunction with soap can be but very slow and slight. Sulphur soaps +are, however, very commonly sold, and 10 per cent. is the strength +usually advocated, though many so-called sulphur soaps actually contain +very little sulphur. They are said to be efficacious for acne and +rosacea. + +Sulphur soaps, when dissolved in water, gradually generate sulphuretted +hydrogen, which, although characteristic, makes their use disagreeable +and lessens their popular estimation. + +_Terebene._--The addition of this substance to soap, though imparting a +very refreshing and pleasant odour, does not materially increase the +disinfectant value of the soap. A suitable strength is 5 per cent. + +_Thymol._--This furnishes a not unpleasant, and very useful antiseptic +soap, recommended especially for the cleansing of ulcerated wounds and +restoring the skin to a healthy state. The normal strength is 3 per +cent. It is preferable to replace part of the thymol with red thyme oil, +the thymene of which imparts a sweeter odour to the soap than if +produced with thymol alone. A suitable blend is 2-1/2 per cent. of +thymol crystals and 1-1/2 per cent. of a good red thyme oil. + +Of the vast number of less known proposed additions to toilet soaps, +mention may be made in passing of:-- + +_Fluorides._--These have been somewhat popular during recent years for +the disinfection of breweries, etc., and also used to some extent as +food preservatives. Of course only neutral fluorides are available for +use in soap, acid fluorides and soap being obviously incompatible. In +the authors' experience, however, sodium fluoride appears to have little +value as a germicide when added to soap, such soaps being found to +rapidly become rancid and change colour. + +_Albumen._--The use of albumen--egg, milk, and vegetable--in soap has +been persistently advocated in this country during the past few years. +The claims attributed to albumen are, that it neutralises free alkali, +causes the soap to yield a more copious lather, and helps to bind it +more closely, and a further inducement held out is that it allows more +water to be left in the soap without affecting its firmness. Experiments +made by the authors did not appear to justify any enthusiasm on the +subject, and the use of albumen for soap-making in this country appears +to be very slight, however popular it may be on the Continent. Numerous +other substances have been proposed for addition to soaps, including +yeast, tar from peat (sphagnol), Swedish wood tar, permanganate of +potash, perborates and percarbonates of soda and ammonia, chlorine +compounds, but none of these has at present come much into favour, and +some had only ephemeral existence. Of the many drugs that it has been +suggested to admix in soap for use in allaying an irritable condition of +the skin, the majority are obviously better applied in the form of +ointments, and we need not consider them further. + +_Ether Soap._--Another form of medicated soap made by a few firms is a +liquid ether soap containing mercuric iodide, and intended for surgeons' +use. This, as a rule, consists of a soap made from olive oil and potash, +dissolved in alcohol and mixed with ether, the mercuric iodide being +dissolved in a few drops of water containing an equal weight of +potassium iodide, and this solution added to the alcohol-ether soap. + +_Floating Soaps._--Attempts have been made to produce tablets of soap +that will float upon the surface of water, by inserting cork, or floats, +or a metallic plate in such a manner that there is an air space between +the metal and the soap. The more usual method is to incorporate into +hot soap sufficient air, by means of a specially designed self-contained +jacketed crutcher, in which two shafts carrying small blades or paddles +rotate in opposite directions, to reduce the density of the soap below +that of water and so enable the compressed tablet to float. The +difference in weight of a tablet of the same size before and after +aerating amounts to 10 per cent. + +Ordinary milling soap is used as a basis for this soap; the settled soap +direct from the copper at 170° F. (77° C.) is carefully neutralised with +bicarbonate of sodium, oleic or stearic acids, or boro-glyceride, +perfumed and aerated. + +Floating soap, which is usually white (some are of a cream tint), cannot +be recommended as economical, whilst its deficiency in lathering +properties, owing to occluded air, is a serious drawback to its +popularity as a toilet detergent. + +_Shaving Soaps._--The first essential of a shaving soap, apart from its +freedom from caustic alkali or any substance exerting an irritating +effect upon the skin, is the quick production of a profuse creamy lather +which is lasting. Gum tragacanth is used in some cases to give lasting +power or durability, but is not necessary, as this property is readily +attained by the use of a suitable proportion of potash soap. The best +shaving soaps are mixtures of various proportions of neutral soda and +potash soaps, produced by the combination of ordinary milling base with +a white potash soap, either melted or milled together. Glycerine is +sometimes added, and is more satisfactorily milled in. + +Every precaution should be taken to ensure thorough saponification of +the soaps intended for blending in shaving soap, otherwise there will be +a tendency to become discoloured and develop rancidity with age. Shaving +soaps are delicately perfumed, and are placed on the market either in +the form of sticks which are cut from the bar of soap as it leaves the +compressor, or stamped in flat cakes. + +Shaving creams and pastes are of the same nature as shaving soaps, but +usually contain a larger proportion of superfatting material and +considerably more water. + + +TEXTILE SOAPS. + +In the woollen, cloth, and silk textile industries, the use of soap for +detergent and emulsifying purposes is necessary in several of the +processes, and the following is a brief description of the kinds of soap +successfully employed in the various stages. + +1. _Woollen Industry._--The scouring of wool is the most important +operation--it is the first treatment raw wool is subjected to, and if it +is not performed in an efficient manner, gives rise to serious +subsequent troubles to manufacturer, dyer, and finisher. + +The object of scouring wool is to remove the wool-fat and wool +perspiration (exuded from the skin of sheep), consisting of cholesterol +and isocholesterol, and potassium salts of fatty acids, together with +other salts, such as sulphates, chlorides, and phosphates. This is +effected by washing in a warm dilute soap solution, containing in the +case of low quality wool, a little carbonate of soda; the fatty matter +is thereby emulsified and easily removed. + +Soap, to be suitable for the purpose, must be free from uncombined +caustic alkali, unsaponified fat, silicates, and rosin. + +Wool can be dissolved in a moderately dilute solution of caustic soda, +and the presence of this latter in soap, even in small quantities, is +therefore liable to injure the fibres and make the resultant fabric +possess a harsh "feel," and be devoid of lustre. + +Unsaponified fat denotes badly made soap--besides reducing the +emulsifying power of the liberated alkali, this fat may be absorbed by +the fibres and not only induce rancidity but also cause trouble in +dyeing. + +Soaps containing silicates may have a deleterious action upon the +fibres, causing them to become damaged and broken. + +By general consent soaps containing rosin are unsuitable for use by +woollen manufacturers, as they produce sticky insoluble lime and +magnesia compounds which are deposited upon the fibres, and give rise to +unevenness in the dyeing. + +A neutral olive-oil soft soap is undoubtedly the best for the purpose of +wool scouring, as, owing to its ready solubility in water, it quickly +penetrates the fibres, is easily washed out, and produces a good "feel" +so essential in the best goods, and tends to preserve the lustre and +pliability of the fibre. + +The high price of olive-oil soap, however, renders its use prohibitive +for lower class goods, and in such cases no better soap can be suggested +than the old-fashioned curd mottled or curd soaps (boiled very dry), as +free as possible from uncombined caustic alkali. The raw wool, after +this cleansing operation, is oiled with olive oil or oleine, prior to +spinning; after spinning and weaving, the fabric, in the form of yarn or +cloth, has to be scoured to free it from oil. The soap in most general +use for scouring woollen fabrics is neutral oleine-soda soap. Some +manufacturers prefer a cheap curd soap, such as is generally termed +"second curd," and in cases where lower grades of wools are handled, the +user is often willing to have soap containing rosin (owing to its +cheapness) and considers a little alkalinity desirable to assist in +removing the oil. + +Another operation in which soap is used, is that of milling or fulling, +whereby the fabric is made to shrink and thus becomes more compact and +closer in texture. The fabric is thoroughly cleansed, for which purpose +the soap should be neutral and free from rosin and silicates, otherwise +a harsh feeling or stickiness will be produced. Curd soaps or +finely-fitted soaps made from tallow or bleached palm oil, with or +without the addition of cocoa-nut oil, give the best results. All traces +of soap must be carefully removed if the fabric is to be dyed. + +The woollen dyer uses soap on the dyed pieces to assist the milling, +and finds that a good soap, made from either olive oil, bleached palm +oil, or tallow, is preferable, and, although it is generally specified +to be free from alkali, a little alkalinity is not of consequence, for +the woollen goods are, as a rule, acid after dyeing, and this alkalinity +would be instantly neutralised. + +2. _Cotton Industry._--Cotton fibres are unacted upon by caustic alkali, +so that the soap used in cleaning and preparing cotton goods for dyeing +need not be neutral, in fact alkalinity is a distinct advantage in order +to assist the cleansing. + +Any curd soap made from tallow, with or without the addition of a small +quantity of cocoa-nut oil, may be advantageously used for removing the +natural oil. + +In cotton dyeing, additions of soap are often made to the bath, and in +such cases the soap must be of good odour and neutral, lest the colours +should be acted upon and tints altered. Soaps made from olive oil and +palm oil are recommended. The same kind of soap is sometimes used for +soaping the dyed cotton goods. + +The calico-printer uses considerable quantities of soap for cleansing +the printed-cloths. The soap not only cleanses by helping to remove the +gummy and starchy constituents of the adhering printing paste, but also +plays an important part in fixing and brightening the colours. Soaps +intended for this class of work must be quite neutral (to obviate any +possible alteration in colour by the action of free alkali), free from +objectionable odour and rosin, and readily soluble in water. These +qualities are possessed by olive-oil soaps, either soft or hard. A +neutral olive-oil soft soap, owing to its solubility in cold water, may +be used for fibres coloured with most delicate dyes, which would be +fugitive in hot soap solutions, and this soap is employed for the most +expensive work. + +Olive-oil curd (soda) soaps are in general use; those made from palm oil +are also recommended, although they are not so soluble as the olive-oil +soaps. Tallow curd soaps are sometimes used, but the difficulty with +which they dissolve is a drawback, and renders them somewhat unsuitable. + +3. _Silk Industry._--Silk is secured to remove the sericin or silk-glue +and adhering matter from the raw silk, producing thereby lustre on the +softened fibre and thus preparing it for the dyer. + +The very best soap for the purpose is an olive-oil soft soap; olive-oil +and oleine hard soaps may also be used. The soap is often used in +conjunction with carbonate of soda to assist the removal of the sericin, +but, whilst carbonates are permissible, it is necessary to avoid an +excess of caustic soda. + +Tallow soaps are so slowly soluble that they are not applicable to the +scouring of silk. + +The dyer of silk requires soap, which is neutral and of a pleasant +odour. The preference is given to neutral olive-oil soft soap, but hard +soaps (made from olive oil, oleine, or palm oil) are used chiefly on +account of cheapness. It is essential, however, that the soap should be +free from rosin on account of its frequent use and consequent +decomposition in the acid dye bath, when any liberated rosin acids would +cling to the silk fibres and produce disagreeable results. + +_Patent Textile Soaps._--Stockhausen (Eng. Pat. 24,868, 1897) makes +special claim for a soap, termed Monopole Soap, to be used in place of +Turkey-red oils in the dyeing and printing of cotton goods and finishing +of textile fabrics. The soap is prepared by heating the sulphonated oil +(obtained on treatment of castor oil with sulphuric acid) with alkali, +and it is stated that the product is not precipitated when used in the +dye-bath as is ordinary soap, nor is it deposited upon the fibres. + +Another patent (Eng. Pat. 16,382, 1897), has for its object the +obviating of the injurious effects upon wool, of alkali liberated from a +solution of soap. It is proposed to accomplish this by sulphonating part +of the fat used in making the soap. + +_Miscellaneous Soaps._--Under this heading may be classed soaps intended +for special purposes and consisting essentially of ordinary boiled soap +to which additions of various substances have been made. + +With additions of naphtha, fractions of petroleum, and turpentine, the +detergent power of the soap is increased by the action of these +substances in removing grease. + +Amongst the many other additions may be mentioned: ox-gall or +derivatives therefrom (for carpet-cleaning soap), alkali sulphides (for +use of lead-workers), aniline colours (for home-dyeing soaps), pumice +and tripoli (motorists' soaps), pine-needle oil, in some instances +together with lanoline (for massage soaps), pearl-ash (for soap intended +to remove oil and tar stains), magnesia, rouge, ammonium carbonate, +chalk (silversmiths' soap), powdered orris, precipitated chalk, +magnesium carbonate (tooth soaps). + +Soap powders or dry soaps are powdered mixtures of soap, soda ash, or +soda crystals, and other chemicals, whilst polishing soaps often contain +from 85 to 90 per cent. siliceous matter, and can scarcely be termed +soap. + + + + +CHAPTER VIII. + +SOAP PERFUMES. + + _Essential Oils--Source and Preparation--Properties--Artificial + and Synthetic Perfumes._ + + +The number of raw materials, both natural and artificial, at the +disposal of the perfumer, has increased so enormously during recent +years that the scenting of soaps has now become an art requiring very +considerable skill, and a thorough knowledge of the products to be +handled. Not only does the all-important question of odour come into +consideration, but the action of the perfumes on the soap, and on each +other, has also to be taken into account. Thus, many essential oils and +synthetic perfumes cause the soap to darken rapidly on keeping, _e.g._, +clove oil, cassia oil, heliotropin, vanillin. Further, some odoriferous +substances, from their chemical nature, are incompatible with soap, and +soon decompose any soap to which they are added, while in a few cases, +the blending of two unsuitable perfumes results, by mutual reaction, in +the effect of each being lost. In the case of oils like bergamot oil, +the odour value of which depends chiefly on their ester content, it is +very important that these should not be added to soaps containing much +free alkali, as these esters are readily decomposed thereby. Some +perfumes possess the property of helping the soap to retain other and +more delicate odours considerably longer than would otherwise be +possible. Such perfumes are known as "fixing agents" or "fixateurs," and +among the most important of these may be mentioned musk, both natural +and artificial, civet, the oils of Peru balsam, sandalwood, and +patchouli, and benzyl benzoate. + +The natural perfumes employed for addition to soaps are almost entirely +of vegetable origin, and consist of essential oils, balsams, and resins, +animal perfumes such as musk, civet, and ambergris being reserved +principally for the preparation of "extraits". + +As would be expected with products of such diverse character, the +methods employed for the preparation of essential oils vary +considerably. Broadly speaking, however, the processes may be divided +into three classes--(1) _expression_, used for orange, lemon, and lime +oils; (2) _distillation_, employed for otto of rose, geranium, +sandalwood, and many other oils; and (3) _extraction_, including +_enfleurage_, by which the volatile oil from the flowers is either first +absorbed by a neutral fat such as lard, and then extracted therefrom by +maceration in alcohol, or directly extracted from the flowers by means +of a volatile solvent such as benzene, petroleum ether, or chloroform. +The last process undoubtedly furnishes products most nearly resembling +the natural floral odours, and is the only one which does not destroy +the delicate fragrance of the violet and jasmine. The yield, however, is +extremely small, and concrete perfumes prepared in this way are +therefore somewhat costly. + +The essential oils used are derived from upwards of twenty different +botanical families, and are obtained from all parts of the world. Thus, +from Africa we have geranium and clove oils; from America, bay, bois de +rose, Canadian snake root, cedarwood, linaloe, peppermint, petitgrain, +and sassafras; from Asia, camphor, cassia, cinnamon, patchouli, +sandalwood, star anise, ylang-ylang, and the grass oils, _viz._, +citronella, lemongrass, palmarosa, and vetivert; from Australia, +eucalyptus; while in Europe there are the citrus oils, bergamot, lemon, +and orange, produced by Sicily, aspic, lavender, neroli, petitgrain, and +rosemary by France, caraway and clove by Holland, anise by Russia, and +otto of rose by Bulgaria. + +Attempts have been made to classify essential oils either on a botanical +basis or according to their chemical composition, but neither method is +very satisfactory, and, in describing the chief constituents and +properties of the more important oils, we have preferred therefore to +arrange them alphabetically, as being simpler for reference. + +It is a matter of some difficulty to judge the purity of essential oils, +not only because of their complex nature, but owing to the very great +effect upon their properties produced by growing the plants in different +soils and under varying climatic conditions, and still more to the +highly scientific methods of adulteration adopted by unscrupulous +vendors. The following figures will be found, however, to include all +normal oils. + +_Anise Stell_, or _Star Anise_, from the fruit of Illicium verum, +obtained from China. Specific gravity at 15° C., 0.980-0.990; optical +rotation, faintly dextro- or lævo-rotatory, +0° 30' to -2°; refractive +index at 20° C., 1.553-1.555; solidifying point, 14°-17° C.; solubility +in 90 per cent. alcohol, 1 in 3 or 4. + +The chief constituents of the oil are anethol, methyl chavicol, +d-pinene, l-phellandrene, and in older oils, the oxidation products of +anethol, _viz._ anisic aldehyde and anisic acid. Since anethol is the +most valuable constituent, and the solidifying point of the oil is +roughly proportional to its anethol content, oils with a higher +solidifying point are the best. + +_Aspic oil_, from the flowers of Lavandula spica, obtained from France +and Spain, and extensively employed in perfuming household and cheap +toilet soaps; also frequently found as an adulterant in lavender oil. +Specific gravity at 15° C., 0.904-0.913; optical rotation, French, +dextro-rotatory up to +4°, rarely up to +7°, Spanish, frequently +slightly lævo-rotatory to -2°, or dextro-rotatory up to +7°; esters, +calculated as linalyl acetate, 2 to 6 per cent.; most oils are soluble +in 65 per cent. alcohol 1 in 4, in no case should more than 2.5 volumes +of 70 per cent. alcohol be required for solution. + +The chief constituents of the oil are: linalol, cineol, borneol, +terpineol, geraniol, pinene, camphene and camphor. + +_Bay oil_, distilled from the leaves of Pimenta acris, and obtained from +St. Thomas and other West Indian Islands. It is used to some extent as a +perfume for shaving soaps, but chiefly in the Bay Rhum toilet +preparation. Specific gravity at 15° C., 0.965-0.980; optical rotation, +slightly lævo-rotatory up to -3°; phenols, estimated by absorption with +5 per cent. caustic potash solution, from 45 to 60 per cent.; the oil is +generally insoluble in 90 per cent. alcohol, though when freshly +distilled it dissolves in its own volume of alcohol of this strength. + +The oil contains eugenol, myrcene, chavicol, methyl eugenol, methyl +chavicol, phellandrene, and citral. + +_Bergamot oil_, obtained by expression from the fresh peel of the fruit +of Citrus Bergamia, and used very largely for the perfuming of toilet +soaps. Specific gravity at 15° C., 0.880-0.886; optical rotation, +10° +to +20°; esters, calculated as linalyl acetate, 35-40 per cent., and +occasionally as high as 42-43 per cent.; frequently soluble in 1.5 parts +of 80 per cent. alcohol, or failing that, should dissolve in one volume +of 82.5 or 85 per cent. alcohol. When evaporated on the water-bath the +oil should not leave more than 5-6 per cent. residue. + +Among the constituents of this oil are: linalyl acetate, limonene, +dipentene, linalol, and bergaptene. + +_Bitter Almond Oil._--The volatile oil obtained from the fruit of +_Amygdalus communis_. Specific gravity at 15° C., 1.045-1.06; optically +inactive; refractive index at 20° C., 1.544-1.545; boiling point, +176-177° C.; soluble in 1 or 1.5 volumes of 70 per cent. alcohol. + +The oil consists almost entirely of benzaldehyde which may be estimated +by absorption with a hot saturated solution of sodium bisulphite. The +chief impurity is prussic acid, which is not always completely removed. +This may be readily detected by adding to a small quantity of the oil +two or three drops of caustic soda solution, and a few drops of ferrous +sulphate solution containing ferric salt. After thoroughly shaking, +acidulate with dilute hydrochloric acid, when a blue coloration will be +produced if prussic acid is present. + +The natural oil may frequently be differentiated from artificial +benzaldehyde by the presence of chlorine in the latter. As there is now +on the market, however, artificial oil free from chlorine, it is no +longer possible, by chemical means, to distinguish with certainty +between the natural and the artificial product. To test for chlorine in +a sample, a small coil of filter paper, loosely rolled, is saturated +with the oil, and burnt in a small porcelain dish, covered with an +inverted beaker, the inside of which is moistened with distilled water. +When the paper is burnt, the beaker is rinsed with water, filtered, and +the filtrate tested for chloride with silver nitrate solution. + +_Canada snake root oil_, from the root of Asarum canadense. Specific +gravity at 15° C., 0.940-0.962; optical rotation, slightly lævo-rotatory +up to -4°; refractive index at 20° C., 1.485-1.490; saponification +number, 100-115; soluble in 3 or 4 volumes of 70 per cent. alcohol. + +The principal constituents of the oil are a terpene, asarol alcohol, +another alcohol, and methyl eugenol. The oil is too expensive to be used +in other than high-class toilet soaps. + +_Cananga_ or _Kananga oil_, the earlier distillate from the flowers of +Cananga odorata, obtained chiefly from the Philippine Islands. Specific +gravity at 15° C., 0.910-0.940; optical rotation, -17° to -30°; +refractive index at 20° C., 1.4994-1.5024; esters, calculated as linalyl +benzoate, 8-15 per cent.; soluble in 1.5 to 2 volumes of 95 per cent. +alcohol, but becoming turbid on further addition. + +The oil is qualitatively similar in composition to Ylang-Ylang oil, and +contains linalyl benzoate and acetate, esters of geraniol, cadinene, and +methyl ester of p-cresol. + +_Caraway oil_, distilled from the seeds of Carum carui. Specific gravity +at 15° C., 0.907-0.915; optical rotation, +77° to +79°; refractive index +at 20° C., 1.485-1.486; soluble in 3 to 8 volumes of 80 per cent. +alcohol. The oil should contain 50-60 per cent. of carvone, which is +estimated by absorption with a saturated solution of neutral sodium +sulphite. The remainder of the oil consists chiefly of limonene. + +_Cassia oil_, distilled from the leaves of Cinnamomum cassia, and +shipped to this country from China in lead receptacles. Specific gravity +at 15° C., 1.060-1.068; optical rotation, slightly dextro-rotatory up to ++3° 30'; refractive index at 20° C., 1.6014-1.6048; soluble in 3 volumes +of 70 per cent. alcohol as a general rule, but occasionally requires 1 +to 2 volumes of 80 per cent. alcohol. + +The value of the oil depends upon its aldehyde content, the chief +constituent being cinnamic aldehyde. This is determined by absorption +with a hot saturated solution of sodium bisulphite. Three grades are +usually offered, the best containing 80-85 per cent. aldehydes, the +second quality, 75-80 per cent., and the lowest grade, 70-75 per cent. + +Other constituents of the oil are cinnamyl acetate and cinnamic acid. +This oil gives the characteristic odour to Brown Windsor soap, and is +useful for sweetening coal-tar medicated soaps. + +_Cedarwood oil_, distilled from the wood of Juniperus virginiana. +Specific gravity at 15° C., 0.938-0.960; optical rotation, -35° to -45°; +refractive index at 20° C., 1.5013-1.5030. The principal constituents +are cedrene and cedrol. + +_Cinnamon oil_, distilled from the bark of Cinnamomum zeylanicum. +Specific gravity at 15° C., 1.00-1.035; optical rotation, lævo-rotatory +up to -2°; usually soluble in 2 to 3 volumes of 70 per cent. alcohol, +but sometimes requires 1 volume of 80 per cent. alcohol for solution; +aldehydes, by absorption with sodium bisulphite solution, 55-75 per +cent.; and phenols, as measured by absorption with 5 per cent. potash, +not exceeding 12 per cent. + +The value of this oil is not determined entirely by its aldehyde content +as is the case with cassia oil, and any oil containing more than 75 per +cent. aldehydes must be regarded with suspicion, being probably admixed +with either cassia oil or artificial cinnamic aldehyde. The addition of +cinnamon leaf oil which has a specific gravity at 15° C. of 1.044-1.065 +is detected by causing a material rise in the proportion of phenols. +Besides cinnamic aldehyde the oil contains eugenol and phellandrene. + +_Citronella Oil._--This oil is distilled from two distinct Andropogon +grasses, the Lana Batu and the Maha pangiri, the former being the source +of the bulk of Ceylon oil, and the latter being cultivated in the +Straits Settlements and Java. The oils from these three localities show +well-defined chemical differences. + +_Ceylon Citronella oil_ has the specific gravity at 15° C., 0.900-0.920; +optical rotation, lævo-rotatory up to -12°; refractive index at 20° C., +1.480-1.484; soluble in 1 volume of 80 per cent. alcohol; total +acetylisable constituents, calculated as geraniol, 54-70 per cent. + +_Singapore Citronella Oil._--Specific gravity at 15° C., 0.890-0.899; +optical rotation, usually slightly lævo-rotatory up to -3°; refractive +index at 20° C., 1.467-1.471; soluble in 1 to 1.5 volumes of 80 per +cent. alcohol; total acetylisable constituents, calculated as geraniol, +80-90 per cent. + +_Java Citronella Oil._--Specific gravity at 15° C., 0.890-0.901; optical +rotation, -1° to -6°; total acetylisable constituents, calculated as +geraniol, 75-90 per cent.; soluble in 1-2 volumes of 80 per cent. +alcohol. + +The chief constituents of the oil are geraniol, citronellal, linalol, +borneol, methyl eugenol, camphene, limonene, and dipentene. It is very +largely used for perfuming cheap soaps, and also serves as a source for +the production of geraniol. + +_Bois de Rose Femelle oil_, or _Cayenne linaloe oil_, distilled from +wood of trees of the Burseraceæ species. Specific gravity at 15° C., +0.874-0.880; optical rotation, -11° 30' to -16°; refractive index at 20° +C., 1.4608-1.4630; soluble in 1.5 to 2 volumes of 70 per cent. alcohol. + +The oil consists almost entirely of linalol, with traces of saponifiable +bodies, but appears to be free from methyl heptenone, found by Barbier +and Bouveault in Mexican linaloe oil. This oil is distinctly finer in +odour than the Mexican product. + +_Clove oil_, distilled from the unripe blossoms of Eugenia +caryophyllata, the chief source of which is East Africa (Zanzibar and +Pemba). Specific gravity at 15° C., 1.045-1.061; optical rotation, +slightly lævo-rotatory up to -1° 30'; phenols, estimated by absorption +with 5 per cent. potash solution, 86-92 per cent.; refractive index at +20° C., 1.5300-1.5360; soluble in 1 to 2 volumes of 70 per cent. +alcohol. + +The principal constituent of the oil is eugenol, together with +caryophyllene and acet-eugenol. While within certain limits the value of +this oil is determined by its eugenol content, oils containing more than +93 per cent. phenols are usually less satisfactory in odour, the high +proportion of phenols being obtained at the expense of the decomposition +of some of the sesquiterpene. Oils with less than 88 per cent. phenols +will be found somewhat weak in odour. This oil is extensively used in +the cheaper toilet soaps and is an important constituent of carnation +soaps. As already mentioned, however, it causes the soap to darken in +colour somewhat rapidly, and must not therefore be used in any quantity, +except in coloured soaps. + +_Concrete orris oil_, a waxy substance obtained by steam distillation of +Florentine orris root. + +Melting point, 35-45° C., usually 40-45° C.; free acidity, calculated as +myristic acid, 50-80 per cent.; ester, calculated as combined myristic +acid, 4-10 per cent. + +The greater part of the product consists of the inodorous myristic acid, +the chief odour-bearing constituent being irone. The high price of the +oil renders its use only possible in the very best quality soaps. + +_Eucalyptus Oil._--Though there are some hundred or more different oils +belonging to this class, only two are of much importance to the +soap-maker. These are:-- + +(i.) Eucalyptus citriodora. Specific gravity at 15° C., 0.870-0.905; +optical rotation, slightly dextro-rotatory up to +2°; soluble in 4-5 +volumes of 70 per cent. alcohol. + +The oil consists almost entirely of citronellic aldehyde, and on +absorption with saturated solution of sodium bisulphite should leave +very little oil unabsorbed. + +(ii.) Eucalyptus globulus, the oil used in pharmacy, and containing +50-65 per cent. cineol. Specific gravity at 15° C., 0.910-0.930; optical +rotation, +1° to +10°; soluble in 2 to 3 parts of 70 per cent. alcohol; +cineol (estimated by combination with phosphoric acid, pressing, +decomposing with hot water, and measuring the liberated cineol), not +less than 50 per cent. Besides cineol, the oil contains d-pinene, and +valeric, butyric, and caproic aldehydes. It is chiefly used in medicated +soaps. + +_Fennel (sweet) oil_, obtained from the fruit of Foeniculum vulgare, +grown in Germany, Roumania, and other parts of Europe. Specific gravity +at 15° C., 0.965-0.985; optical rotation, +6° to +25°; refractive index +at 20° C., 1.515-1.548; usually soluble in 2-6 parts 80 per cent. +alcohol, but occasionally requires 1 part of 90 per cent. alcohol. + +The chief constituents of the oil are anethol, fenchone, d-pinene, and +dipentene. + +_Geranium oils_, distilled from plants of the Pelargonium species. +There are three principal kinds of this oil on the market--the African, +obtained from Algeria and the neighbourhood, the Bourbon, distilled +principally in the Island of Réunion, and the Spanish. The oil is also +distilled from plants grown in the South of France, but this oil is not +much used by soap-makers. A specially fine article is sold by a few +essential oil firms under the name of "Geranium-sur-Rose," which as its +name implies, is supposed to be geranium oil distilled over roses. This +is particularly suitable for use in high-class soaps. The following are +the general properties of these oils. It will be seen that the limits +for the figures overlap to a considerable extent. + + _________________________________________________________________________ +| | | | | | +| | African. | Bourbon. | Spanish. | French. | +|_________________________|___________|___________|___________|___________| +| | | | | | +| Specific gravity | | | | | +| at 15° C. | .890-.900 | .888-.895 | .895-.898 | .897-.900 | +| Optical rotation. |-6° to -10°|-9° to -18°|-8° to -11°|-8° to -11°| +| Esters, calculated as | 20-27 | 27-32 | 20-27 | 18-23 | +| geranyl tiglate | per cent. | per cent. | per cent. | per cent. | +| Total alcohols, as | 68-75 | 70-80 | 65-75 | 66-75 | +| geraniol. | per cent. | per cent. | per cent. | per cent. | +| Solubility in 70 per | | | | | +| cent. alcohol. | 1 in 1.5-2| 1 in 1.5-2| 1 in 2-3 | 1 in 1.5-2| +|_________________________|___________|___________|___________|___________| + +The oil contains geraniol and citronellol, both free, and combined with +tiglic, valeric, butyric, and acetic acids; also l-menthone. The African +and Bourbon varieties are the two most commonly used for +soap-perfurmery, the Spanish oil being too costly for extensive use. + +_Ginger-grass oil_, formerly regarded as an inferior kind of palma-rosa +but now stated to be from an entirely different source. Specific gravity +at 15° C., 0.889-0.897; optical rotation, +15°. + +The oil contains a large amount of geraniol, together with di-hydrocumin +alcohol, d-phellandrene, d-limonene, dipentene, and l-carvone. + +_Guaiac wood oil_, distilled from the wood of Bulnesia sarmienti. +Specific gravity at 30° C., 0.967-0.975; optical rotation, -4° 30' to +-7°; refractive index at 20° C., 1.506-1.507; soluble in 3 to 5 volumes +of 70 per cent. alcohol. + +The principal constituent of the oil is guaiac alcohol, or gusiol. This +oil, which has what is generally termed a "tea-rose odour," is +occasionally used as an adulterant for otto of rose. + +_Lavender oil_, distilled from the flowers of Lavandula vera, grown in +England, France, Italy and Spain. The English oil is considerably the +most expensive, and is seldom, if ever, used in soap. The French and +Italian oils are the most common, the Spanish oil being a comparatively +new article, of doubtful botanical origin, and more closely resembling +aspic oil. + +English Oil.--Specific gravity at 15° C., 0.883-0.900; optical rotation, +-4° to -10°; esters, calculated as linalyl acetate, 5-10 per cent.; +soluble in 3 volumes of 70 per cent. alcohol. + +French and Italian Oils.--Specific gravity at 15° C., 0.885-0.900; +optical rotation, -2° to -9°; refractive index at 20° C., 1.459-1.464; +esters, calculated as linalyl acetate, 20-40 per cent., occasionally +higher; soluble in 1.5-3 volumes of 70 per cent. alcohol. + +There was at one time a theory that the higher the proportion of ester +the better the oil, but this theory has now to a very large extent +become discredited, and there is no doubt that some of the finest oils +contain less than 30 per cent. of esters. + +Spanish Oil.--Specific gravity at 15° C., 0.900-0.915; optical rotation, +-2° to +7°; esters, calculated as linalyl acetate, 2-6 per cent.; +soluble in 1-2 volumes of 70 per cent. alcohol. + +The chief constituents of lavender oil are linalyl acetate, linalol, +geraniol, and linalyl butyrate, while the English oil also contains a +distinct amount of cineol. + +_Lemon oil_, prepared by expressing the peel of the nearly ripe fruit of +Citrus limonum, and obtained almost entirely from Sicily and Southern +Italy. Specific gravity at 15° C., 0.856-0.860; optical rotation, +58° +to +63°; refractive index at 20° C., 1.4730-1.4750; aldehydes (citral), +2.5 to 4 per cent. + +The principal constituents of the oil are limonene and citral, together +with small quantities of pinene, phellandrene, octyl and nonyl +aldehydes, citronellal, geraniol, geranyl acetate, and the stearopten, +citraptene. + +_Lemon-grass_ (so-called _verbena_) oil, distilled from the grass +Andropogon citratus, which is grown in India and, more recently, in the +West Indies. The oils from these two sources differ somewhat in their +properties, and also in value, the former being preferred on account of +its greater solubility in alcohol. + +East Indian.--Specific gravity at 15° C., 0.898-0.906; optical rotation, +-0° 30' to -6°; aldehydes, by absorption with bisulphite of soda +solution, 65 to 78 per cent.; refractive index at 20° C., 1.485-1.487; +soluble in 2-3 volumes of 70 per cent. alcohol. + +West Indian.--Specific gravity at 15° C., 0.886-0.893; optical rotation, +faintly lævo-gyrate; refractive index at 20° C., 1.4855-1.4876; soluble +in 0.5 volume of 90 per cent. alcohol. + +_Lime oil_, obtained by expression or distillation of the peel of the +fruit of Citrus medica, and produced principally in the West Indies. + +Expressed Oil.--Specific gravity at 15° C., 0.870-0.885; optical +rotation, +38° to +50°. Its most important constituent is citral. + +Distilled Oil.--This is entirely different in character to the expressed +oil. Its specific gravity at 15° C. is 0.854-0.870; optical rotation, ++38° to +54°; soluble in 5-8 volumes of 90 per cent. alcohol. + +_Linaloe oil_, distilled from the wood of trees of the Burseraceæ +family, and obtained from Mexico. Specific gravity at 15° C., +0.876-0.892; optical rotation, usually lævo-rotatory, -3° to -13°, but +occasionally dextro-rotatory up to +5° 30'; esters, calculated as +linalyl acetate, 1-8 per cent.; total alcohols as linalol, determined by +acetylation, 54-66 per cent.; soluble in 1-2 volumes of 70 per cent. +alcohol. + +This oil consists mainly of linalol, together with small quantities of +methyl heptenone, geraniol, and d-terpineol. + +_Marjoram oil_, distilled from Origanum majoranoides, and obtained +entirely from Cyprus. Specific gravity at 15° C., 0.966; phenols, +chiefly carvacrol, estimated by absorption with 5 per cent. caustic +potash solution, 80-82 per cent.; soluble in 2-3 volumes of 70 per cent. +alcohol. + +This oil is used in soap occasionally in place of red thyme oil. + +_Neroli Bigarade oil_, distilled from the fresh blossoms of the bitter +orange, Citrus bigaradia. Specific gravity at 15° C., 0.875-0.882; +optical rotation, +0° 40' to +10°, and occasionally much higher; +refractive index at 20° C., 1.468-1.470; esters, calculated as linalyl +acetate, 10-18 per cent.; soluble in 0.75-1.75 volumes of 80 per cent. +alcohol, becoming turbid on further addition of alcohol. + +The chief constituents of the oil are limonene, linalol, linalyl +acetate, geraniol, methyl anthranilate, indol, and neroli camphor. + +_Orange (sweet) oil_, expressed from the peel of Citrus aurantium. +Specific gravity at 15° C., 0.849-0.852; optical rotation, +95° to +99°; +refractive index at 20° C., 1.4726-1.4732. + +The oil contains some 90 per cent. limonene, together with nonyl +alcohol, d-linalol, d-terpineol, citral, citronellal, decyl aldehyde, +and methyl anthranilate. + +_Palmarosa_, or _East Indian geranium oil_, distilled from Andropogon +Schoenanthus, a grass widely grown in India. Specific gravity at 15° +C., 0.888-0.895; optical rotation, +1° to -3°; refractive index at 20° +C., 1.472-1.476; esters, calculated as linalyl acetate, 7-14 per cent.; +total alcohols, as geraniol, 75-93 per cent.; solubility in 70 per cent. +alcohol, 1 in 3. + +The oil consists chiefly of geraniol, free, and combined with acetic and +caproic acids, and dipentene. It is largely used in cheap toilet soaps, +particularly in rose soaps. It is also a favourite adulterant for otto +of rose, and is used as a source of geraniol. + +_Patchouli oil_, distilled from the leaves of Pogostemon patchouli, a +herb grown in India and the Straits Settlements. Specific gravity at 15° +C., 0.965-0.990; optical rotation, -45° to -63°; refractive index at 20° +C., 1.504-1.511; saponification number, up to 12; sometimes soluble in +0.5 to 1 volume of 90 per cent. alcohol, becoming turbid on further +addition. The solubility of the oil in alcohol increases with age. The +oil consists to the extent of 97 per cent. of patchouliol and cadinene, +which have little influence on its odour, and the bodies responsible for +its persistent and characteristic odour have not yet been isolated. + +_Peppermint oil_, distilled from herbs of the Mentha family, the +European and American from Mentha piperita, and the Japanese being +generally supposed to be obtained from Mentha arvensis. The locality in +which the herb is grown has a considerable influence on the resulting +oil, as the following figures show:-- + +English.--Specific gravity at 15° C., 0.900-0.910; optical rotation, +-22° to -33°; total menthol, 55-66 per cent.; free menthol, 50-60 per +cent.; soluble in 3-5 volumes of 70 per cent. alcohol. + +American.--Specific gravity at 15° C., 0.906-0.920; optical rotation, +-20° to -33°; total menthol, 50-60 per cent.; free menthol, 40-50 per +cent. The Michigan oil is soluble in 3-5 volumes of 70 per cent. +alcohol, but the better Wayne County oil usually requires 1-2 volumes of +80 per cent. alcohol, and occasionally 0.5 volume of 90 per cent. +alcohol. + +French.--Specific gravity at 15° C., 0.917-0.925; optical rotation, -6° +to -10°; total menthol, 45-55 per cent.; free menthol, 35-45 per cent.; +soluble in 1 to 1.5 volumes of 80 per cent. + +Japanese.--Specific gravity at 25° C., 0.895-0.900; optical rotation, +lævo-rotatory up to -43°; solidifies at 17 to 27° C.; total menthol, +70-90 per cent., of which 65-85 per cent. is free; soluble in 3-5 +volumes of 70 per cent. alcohol. + +The dementholised oil is fluid at ordinary temperatures, has a specific +gravity of 0.900-0.906 at 15° C., and contains 50-60 per cent. total +menthol. + +Some twenty different constituents have been found in American +peppermint oil, including menthol, menthone, menthyl acetate, cineol, +amyl alcohol, pinene, l-limonene, phellandrene, dimethyl sulphide, +menthyl isovalerianate, isovalerianic aldehyde, acetaldehyde, acetic +acid, and isovalerianic acid. + +_Peru balsam oil_, the oily portion (so-called "cinnamein") obtained +from Peru balsam. Specific gravity at 15° C., 1.100-1.107; optical +rotation, slightly dextro-rotatory up to +2°; refractive index at 20° +C., 1.569 to 1.576; ester, calculated as benzyl benzoate, 80-87 per +cent.; soluble in 1 volume of 90 per cent. alcohol. + +The oil consists chiefly of benzyl benzoate and cinnamate, together with +styracin, or cinnamyl cinnamate, and a small quantity of free benzoic +and cinnamic acids. + +_Petitgrain oil_, obtained by distillation of the twigs and unripe fruit +of Citrus bigaradia. There are two varieties of the oil, the French and +the South American, the former being the more valuable. Specific gravity +at 15° C., 0.886-0.900; optical rotation, -3° to +6°; refractive index +at 20° C., 1.4604-1.4650; esters, calculated as linalyl acetate, 40-55 +per cent., for the best qualities usually above 50 per cent.; soluble as +a rule in 2-3 volumes of 70 per cent. alcohol, but occasionally requires +1-2 volumes of 80 per cent. alcohol. + +Among its constituents are limonene, linalyl acetate, geraniol and +geranyl acetate. + +_Pimento oil_ (allspice), distilled from the fruit of Pimenta +officinalis, which is found in the West Indies and Central America. +Specific gravity at 15° C., 1.040-1.060; optical rotation, slightly +lævo-rotatory up to -4°; refractive index at 20° C., 1.529-1.536; +phenols, estimated by absorption with 5 per cent. potash solution, +68-86 per cent.; soluble in 1-2 volumes of 70 per cent. alcohol. + +The oil contains eugenol, methyl eugenol, cineol, phellandrene, and +caryophyllene. + +_Rose oil (otto of rose)_, distilled from the flowers of Rosa damascena, +though occasionally the white roses (Rosa alba) are employed. The +principal rose-growing district is in Bulgaria, but a small quantity of +rose oil is prepared from roses grown in Anatolia, Asia Minor. An +opinion as to the purity of otto of rose can only be arrived at after a +very full chemical analysis, supplemented by critical examination of its +odour by an expert. The following figures, however, will be found to +include most oils which can be regarded as genuine. Specific gravity at +30° C., 0.850-0.858; optical rotation at 30° C., -1° 30' to -3°; +refractive index at 20° C., 1.4600-1.4645; saponification value, 7-11; +solidifying point, 19-22° C.; iodine number, 187-194; stearopten +content, 14-20 per cent.; melting point of stearopten, about 32° C. + +A large number of constituents have been isolated from otto of rose, +many of which are, however, only present in very small quantities. The +most important are geraniol, citronellol, phenyl ethyl alcohol, together +with nerol, linalol, citral, nonylic aldehyde, eugenol, a sesquiterpene +alcohol, and the paraffin stearopten. + +_Rosemary oil_, distilled from the herb Rosemarinus officinalis, and +obtained from France, Dalmatia, and Spain. The herb is also grown in +England, but the oil distilled therefrom is rarely met with in commerce. +The properties of the oils vary with their source, and also with the +parts of the plant distilled, distillation of the stalks as well as the +leaves tending to reduce the specific gravity and borneol content, and +increase the proportion of the lævo-rotatory constituent (lævo-pinene). +The following figures may be taken as limits for pure oils:-- + +French and Dalmatian.--Specific gravity at 15° C., 0.900-0.916; optical +rotation, usually dextro-rotatory, up to +15°, but may occasionally be +lævo-rotatory, especially if stalks have been distilled with the leaves; +ester, calculated as bornyl acetate, 1-6 per cent.; total borneol, 12-18 +per cent.; usually soluble in 1-2 volumes of 82.5 per cent. alcohol. + +Spanish.--The properties of the Spanish oil are similar to the others, +except that it is more frequently lævo-rotatory. + +Rosemary oil contains pinene, camphene, cineol, borneol, and camphor. + +_Sandalwood oil_, obtained by distillation of the wood of Santalum album +(East Indian), Santalum cygnorum (West Australian), and Amyris +balsamifera (West Indian). The oils obtained from these three different +sources differ very considerably in value, the East Indian being by far +the best. + +East Indian.--Specific gravity at 15° C., 0.975-0.980; optical rotation, +-14° to -20°; refractive index at 20° C., 1.5045-1.5060; santalol, +92-97 per cent.; usually soluble in 4-6 volumes of 70 per cent. alcohol, +though, an old oil occasionally is insoluble in 70 per cent. alcohol. + +West Australian.--Specific gravity at 15° C., 0.950-0.968; optical +rotation, +5° to +7°; alcohols, calculated as santalol, 73-75 per cent.; +insoluble in 70 per cent. alcohol, but readily dissolves in 1-2 volumes +of 80 per cent. alcohol. + +West Indian.--Specific gravity at 15° C., 0.948-0.967; optical rotation, ++13° 30' to +30°; insoluble in 70 per cent. alcohol. + +In addition to free santalol, the oil contains esters of santalol and +santalal. + +_Sassafras oil_, distilled from the bark of Sassafras officinalis, and +obtained chiefly from America. Specific gravity at 15° C., 1.06-1.08; +optical rotation, +1° 50' to +4°; refractive index at 20° C., +1.524-1.532; soluble in, 6-10 volumes of 85 per cent. alcohol, +frequently soluble in 10-15 volumes of 80 per cent. alcohol. + +The chief constituents are safrol, pinene, eugenol, camphor, and +phellandrene. The removal of safrol, either intentionally or by +accident, owing to cooling of the oil and consequent deposition of the +safrol, is readily detected by the reduction of the specific gravity +below 1.06. + +_Thyme oil, red and white_, distilled from the green or dried herb, +Thymus vulgaris, both French and Spanish oils being met with. These oils +are entirely different in character. + +French.--Specific gravity at 15° C., 0.91-0.933; slightly lævo-rotatory +up to -4°, but usually too dark to observe; phenols, by absorption with +10 per cent. aqueous caustic potash, 25-55 per cent.; refractive index +at 20° C., 1.490-1.500; soluble in 1-1.5 volumes of 80 per cent. +alcohol. + +Spanish.--Specific gravity at 15° C., 0.955-0.966; optical rotation, +slightly lævo-gyrate; phenols, 70-80 per cent.; refractive index at 20° +C.; 1.5088-1.5122; soluble in 2-3 volumes of 70 per cent. alcohol. + +In addition to the phenols, thymol or carvacrol, these oils contain +cymene, thymene and pinene. + +The white thyme oil is produced by rectifying the red oil, which is +generally effected at the expense of a considerable reduction in phenol +content, and hence in real odour value of the oil. + +_Verbena Oil._--The oil usually sold under this name is really +lemon-grass oil (which see _supra_). The true verbena oil or French +verveine is, however, occasionally met with. This is distilled in France +from the verbena officinalis, and has the following properties: Specific +gravity at 15° C., 0.891-0.898; optical rotation, slightly dextro- or +lævo-rotatory; aldehydes, 70-75 per cent.; soluble in 2 volumes of 70 +per cent. alcohol. + +The oil contains citral. + +_Vetivert oil_, distilled from the grass, Andropogon muricatus, or Cus +Cus, and grown in the East Indies. + +Specific gravity at 15° C., 1.01-1.03; optical rotation, +20° to +26°; +saponification number, 15-30; refractive index at 20° C., 1.521-1.524; +soluble in 2 volumes of 80 per cent. alcohol. + +The price of this oil makes its use prohibitive except in the highest +class soaps. + +_Wintergreen Oil._--There are two natural sources of this oil, the +Gaultheria procumbens and the Betula lenta. Both oils consist almost +entirely of methyl salicylate and are practically identical in +properties, the chief difference being that the former has a slight +lævo-rotation, while the latter is inactive. + +Specific gravity at 15° C., 1.180-1.187; optical rotation, Gaultheria +oil, up to -1°, Betula oil, inactive; ester as methyl salicylate, at +least 98 per cent.; refractive index at 20° C., 1.5354-1.5364; soluble +in 2-6 volumes of 70 per cent. alcohol. + +Besides methyl salicylate, the oil contains triaconitane, an aldehyde or +ketone, and an alcohol. + +_Ylang-ylang oil_, distilled from the flowers of Cananga odorata, the +chief sources being the Philippine Islands and Java. Specific gravity at +15° C., 0.924-0.950; optical rotation, -30° to -60°, and occasionally +higher; refractive index at 20° C., 1.496-1.512; ester, calculated as +linalyl benzoate, 27-45 per cent., occasionally up to 50 per cent.; +usually soluble in 1/2 volume of 90 per cent. alcohol. + +The composition of the oil is qualitatively the same as that of Cananga +oil, but it is considerably more expensive and therefore can only be +used in the highest grade soaps. + + +_Artificial and Synthetic Perfumes._ + +During the past few years the constitution of essential oils has been +studied by a considerable number of chemists, and the composition of +many oils has been so fully determined that very good imitations can +often be made at cheaper prices than those of the genuine oils, +rendering it possible to produce cheap soaps having perfumes which were +formerly only possible in the more expensive article. + +There is a considerable distinction, however, often lost sight of, +between an _artificial_ and a _synthetic_ oil. An artificial oil may be +produced by separating various constituents from certain natural oils, +and so blending these, with or without the addition of other substances, +as to produce a desired odour, the perfume being, at any rate in part, +obtained from natural oils. A synthetic perfume, on the other hand, is +entirely the product of the chemical laboratory, no natural oil or +substance derived therefrom entering into its composition. + +The following are among the most important bodies of this class:-- + +_Amyl salicylate_, the ester prepared from amyl alcohol and salicylic +acid, sometimes known as "Orchidée" or "Trèfle". This is much used for +the production of a clover-scented soap. It has the specific gravity at +15° C., 1.052-1.054; optical rotation, +1° 16' to +1° 40'; refractive +index at 20° C., 1.5056; and should contain not less than 97 per cent. +ester, calculated as amyl salicylate. + +_Anisic aldehyde_, or _aubépine_, prepared by oxidation of anethol, and +possessing a pleasant, hawthorn odour. This has the specific gravity at +15° C., 1.126; refractive index at 20° C., 1.5693; is optically +inactive, and dissolves readily in one volume of 70 per cent. alcohol. + +_Benzyl Acetate_, the ester obtained from benzyl alcohol and acetic +acid. This has a very strong and somewhat coarse, penetrating odour, +distinctly resembling jasmine. Its specific gravity at 15° C. is +1.062-1.065; refractive index at 20° C., 1.5020; and it should contain +at least 97-98 per cent. ester, calculated as benzyl acetate. + +_Citral_, the aldehyde occurring largely in lemon-grass and verbena +oils, also to a less extent in lemon and orange oils, and possessing an +intense lemon-like odour. It has a specific gravity at 15° C., +0.896-0.897, is optically inactive, and should be entirely absorbed by a +hot saturated solution of sodium bisulphite. + +_Citronellal_, an aldehyde possessing the characteristic odour of +citronella oil, in which it occurs to the extent of about 20 per cent., +and constituting considerably over 90 per cent. of eucalyptus citriodora +oil. Its specific gravity at 15° C. is 0.862; refractive index at 20° +C., 1.447; optical rotation, +8° to +12°; and it should be entirely +absorbed by a hot saturated solution of sodium bisulphite. + +_Coumarin_, a white crystalline product found in Tonka beans, and +prepared synthetically from salicylic acid. It has an odour resembling +new-mown hay, and melts at 67° C. + +_Geraniol_, a cyclic alcohol, occurring largely in geranium, palma-rosa, +and citronella oils. Its specific gravity at 15° C. is 0.883-0.885; +refractive index at 20° C., 1.4762-1.4770; it is optically inactive, and +boils at 218°-225° C. + +_Heliotropin_, which possesses the characteristic odour of heliotrope, +is prepared artificially from safrol. It crystallises in small prisms +melting at 86° C. + +_Hyacinth._--Most of the articles sold under this name are secret blends +of the different makers. Styrolene has an odour very much resembling +hyacinth, and probably forms the basis of most of these preparations, +together with terpineol, and other artificial bodies. The properties of +the oil vary considerably for different makes. + +_Ionone_, a ketone first prepared by Tiemann, and having when diluted a +pronounced violet odour. It is prepared by treating a mixture of citral +and acetone with barium hydrate, and distilling in vacuo. Two isomeric +ketones, [alpha]-ionone and [beta]-ionone, are produced, the article +of commerce being usually a mixture of both. The two ketones have the +following properties:-- + +Alpha-ionone.--Specific gravity at 15° C., 0.9338; refractive index at +16.5 C., 1.50048 (Chuit); optically it is inactive. + +Beta-ionone.--Specific gravity at 15° C., 0.9488; refractive index at +16.8° C., 1.52070 (Chuit); optically it is inactive also. + +The product is usually sold in 10 or 20 per cent. alcoholic solution +ready for use. + +_Jasmine._--This is one of the few cases in which the artificial oil is +probably superior to that obtained from the natural flowers, possibly +due to the extreme delicacy of the odour, and its consequent slight +decomposition during preparation from the flowers. The chemical +composition of the floral perfume has been very exhaustively studied, +and the artificial article now on the market may be described as a +triumph of synthetical chemistry. Among its constituents are benzyl +acetate, linalyl acetate, benzyl alcohol, indol, methyl anthranilate, +and a ketone jasmone. + +_Linalol_, the alcohol forming the greater part of linaloe and bois de +rose oils, and found also in lavender, neroli, petitgrain, bergamot, and +many other oils. The article has the specific gravity at 15° C., +0.870-0.876; optical rotation, -12° to -14°; refractive index at 20° C., +1.463-1.464; and when estimated by acetylation, yields about 70 per +cent. of alcohols. + +_Linalyl acetate_, or _artificial bergamot oil_, is the ester formed +when linalol is treated with acetic anhydride. It possesses a +bergamot-like odour, but it is doubtful whether its value is +commensurate with its greatly increased price over that of ordinary +bergamot oil. It has the specific gravity at 15° C., 0.912. + +_Musk (Artificial)._--Several forms of this are to be obtained, +practically all of which are nitro-derivatives of aromatic hydrocarbons. +The original patent of Baur, obtained in 1889, covered the +tri-nitro-derivative of tertiary butyl xylene. The melting point of the +pure article usually lies between 108° and 112° C., and the solubility +in 95 per cent. alcohol ranges from 1 in 120 to 1 in 200, though more +soluble forms are also made. + +An important adulterant, which should always be tested for, is +acetanilide (antifebrin), which may be detected by the characteristic +isocyanide odour produced when musk containing this substance is boiled +with alcoholic potash, and a few drops of chloroform added. Acetanilide +also increases the solubility in 95 per cent. alcohol. + +_Neroli Oil (Artificial)._--Like jasmine oil, the chemistry of neroli +oil is now very fully known, and it is therefore possible to prepare an +artificial product which is a very good approximation to the natural +oil, and many such are now on the market, which, on account of their +comparative cheapness, commend themselves to the soap-perfumer. These +consist chiefly of linalol, geraniol, linalyl acetate, methyl +anthranilate, and citral. + +_Mirbane Oil_ or _Nitrobenzene._--This is a cheap substitute for oil of +bitter almonds, or benzaldehyde, and is a very coarse, irritating +perfume, only suitable for use in the very cheapest soaps. It is +prepared by the action of a mixture of nitric and sulphuric acids on +benzene at a temperature not exceeding 40° C. Its specific gravity is +1.205-1.206; refractive index at 20° C., 1.550; and boiling point, 206° +C. + +_Niobe oil_, or _ethyl benzoate_, the ester obtained from ethyl alcohol +and benzoic acid, and having the specific gravity at 15° C., +1.094-1.095; refractive index at 20° C., 1.5167; boiling point, +196.5°-198° C.; soluble in 1.5 volumes of 70 per cent. alcohol. + +_Oeillet_ is a combination possessed of a sweet carnation-like odour and +having as a basis, eugenol or isoeugenol. Its properties vary with the +source of supply. + +_Rose Oil (Artificial)._--Several good and fairly cheap artificial rose +oils are now obtainable, consisting chiefly of citronellol, geraniol, +linalol, phenyl ethyl alcohol, and citral. In some cases stearopten or +other wax is added, to render the oil more similar in appearance to the +natural article, but as these are inodorous, no advantage is gained in +this way, and there is, further, the inconvenience in cold weather of +having to first melt the oil before use. + +_Safrol_, an ether which is the chief constituent of sassafras oil, and +also found in considerable quantity in camphor oil. It is sold as an +artificial sassafras oil, and is very much used in perfuming cheap +toilet or household soaps. Its specific gravity at 15° C. is +1.103-1.106; refractive index at 20° C., 1.5373; and it dissolves in +fifteen volumes of 80 per cent. alcohol. + +_Santalol_, the alcohol or mixture of alcohols obtained from sandalwood +oil. Its specific gravity at 15° C. is 0.9795; optical rotation, -18°; +and refractive index at 20° C., 1.507. + +_Terebene_, a mixture of dipentene and other hydrocarbons prepared from +turpentine oil by treatment with concentrated sulphuric acid, is used +chiefly in medicated soaps. Its specific gravity at 15° C. is +0.862-0.868; the oil is frequently slightly dextro- or lævo-rotatory; +the refractive index at 20° C., 1.470-1.478. + +_Terpineol_, an alcohol also prepared from turpentine oil by the action +of sulphuric acid, terpene hydrate being formed as an intermediate +substance. It has a distinctly characteristic lilac odour, and on +account of its cheapness is much used in soap perfumery, especially for +a lilac or lily soap. Its specific gravity at 15° C. is 0.936-0.940; +refractive index at 20° C., 1.4812-1.4835; and boiling point about +210°-212° C. It is optically inactive, and readily soluble in 1.5 +volumes of 70 per cent. alcohol. + +_Vanillin_, a white crystalline solid, melting at 80°-82° C. and +prepared by the oxidation of isoeugenol. It has a strong characteristic +odour, and occurs, associated with traces of benzoic acid and +heliotropin, in the vanilla bean. It can only be used in small quantity +in light-coloured soaps, as it quickly tends to darken the colour of the +soap. + + + + +CHAPTER IX. + +GLYCERINE MANUFACTURE AND PURIFICATION. + + _Treatment of Lyes--Evaporation to Crude + Glycerine--Distillation--Distilled and Dynamite + Glycerine--Chemically Pure Glycerine--Animal Charcoal for + Decolorisation--Glycerine obtained by other Methods of + Saponification--Yield of Glycerine from Fats and Oils._ + + +As pointed out in Chapter II. the fatty acids, which, combined with soda +or potash, form soap, occur in nature almost invariably in the form of +glycerides, _i.e._, compounds of fatty acids with glycerol, and as the +result of saponification of a fat or oil glycerine is set free. + +In Chapter V. processes of soap-making are described in which (1) the +glycerine is retained in the finished soap, and (2) the glycerine is +contained in the lyes, in very dilute solution, contaminated with salt +and other impurities. These lyes, though now constituting the chief +source of profit in the manufacture of cheap soaps, were till early in +last century simply run down the drains as waste liquor. + +Much attention has been devoted to the purification and concentration of +glycerine lyes; and elaborate plant of various forms has been devised +for the purpose. + +_Treatment of Lyes._--The spent lyes withdrawn from the soap-pans are +cooled, and the soap, which has separated during the cooling, is +carefully removed and returned to the soap-house for utilisation in the +manufacture of brown soap. Spent lyes may vary in their content of +glycerol from 3 to 8 per cent., and this depends not only upon the +system adopted in the working of the soap-pans, but also upon the +materials used. Although, in these days of pure caustic soda, spent lyes +are more free from impurities than formerly, the presence of sulphides +and sulphites should be carefully avoided, if it is desired to produce +good glycerine. + +The lyes are transferred to a lead-lined tank of convenient size, and +treated with commercial hydrochloric acid and aluminium sulphate, +sufficient being added of the former to neutralise the free alkali, and +render the liquor faintly acid, and of the latter to completely +precipitate the fatty acids. The acid should be run in slowly, and the +point when enough has been added, is indicated by blue litmus paper +being slightly reddened by the lyes. + +The whole is then agitated with air, when a sample taken from the tank +and filtered should give a clear filtrate. + +Having obtained this clear solution, agitation is stopped, and the +contents of the tank passed through a filter press. The scum, which +accumulates on the treatment tank, may be transferred to a perforated +box suspended over the tank, and the liquor allowed to drain from it. +The filtered liquor is now rendered slightly alkaline by the addition of +caustic soda or carbonate, and, after filtering, is ready for +evaporation. + +The acid and alum salt used in the above treatment must be carefully +examined for the presence of arsenic, and any deliveries of either +article, which contain that impurity, rejected. + +Lime, bog ore, and various metallic salts, such as ferric chloride, +barium chloride, and copper sulphate have been suggested, and in some +instances are used instead of aluminium sulphate, but the latter is +generally employed. + +_Evaporation to Crude Glycerine._--The clear treated lyes, being now +free from fatty, resinous, and albuminous matter, and consisting +practically of an aqueous solution of common salt (sodium chloride) and +glycerine, is converted into crude glycerine by concentration, which +eliminates the water and causes most of the salt to be deposited. + +This concentration was originally performed in open pans heated by fire +or waste combustible gases. In the bottom of each pan was placed a dish +in which the salt deposited, and this dish was lifted out periodically +by the aid of an overhead crane and the contents emptied and washed. +Concentration was continued until the temperature of the liquor was 300° +F. (149° C.), when it was allowed to rest before storing. + +This liquor on analysis gave 80 per cent. glycerol and from 9 to 10-1/2 +per cent. salts (ash); hence the present standard for crude glycerine. + +Concentration in open pans has now been superseded by evaporation _in +vacuo_. The subject of the gradual development of the modern efficient +evaporating plant from the vacuum pan, originated and successfully +applied by Howard in 1813 in the sugar industry, is too lengthy to +detail here, suffice it to say that the multiple effects now in vogue +possess distinct advantages--the greatest of these being increased +efficiency combined with economy. + +The present type of evaporator consists of one or more vessels, each +fitted with a steam chamber through which are fixed vertical hollow +tubes. The steam chamber of the first vessel is heated with direct +steam, or with exhaust steam (supplied from the exhaust steam receiver +into which passes the waste steam of the factory); the treated lyes +circulating through the heated tubes is made to boil at a lower +temperature, with the reduced pressure, than is possible by heating in +open pans. + +The vapour given off by the boiling liquor is conveyed through large +pipes into the steam chamber of the second vessel, where its latent heat +is utilised in producing evaporation, the pressure being further +reduced, as this second vessel is under a greater vacuum than No. 1. +Thus we get a "double effect," as the plant consisting of two pans is +termed. The vapours discharged from the second vessel during boiling are +passed through pipes to the steam chamber of the third vessel (in a +"triple effect"), and there being condensed, create a partial vacuum in +the second vessel. The third vessel may also be heated by means of live +steam. The vapours arising from the last vessel of the evaporating +plant, or in the case of a "single effect" from the vessel, are conveyed +into a condenser and condensed by injection water, which is drawn off by +means of the pump employed for maintaining a vacuum of 28 inches in the +vessel. + +In the most recent designs of large evaporative installations, the +vapours generated from the last vessel are drawn through a device +consisting of a number of tubes enclosed in a casing, and the latent +heat raises the temperature of the treated lyes proceeding through the +tubes to supply the evaporator. + +It will thus be observed that the object of multiple effects is to +utilise all the available heat in performing the greatest possible +amount of work. Special devices are attached to the plant for +automatically removing the condensed water from the steam chambers +without the loss of useful heat, and as a precaution against splashing +over and subsequent loss of glycerine through conveyance to the steam +chamber, dash plates and "catch-alls" or "save-alls" of various designs +are fitted on each vessel. + +In working the plant, the liquor in each vessel is kept at a fairly +constant level by judicious feeding from one to the other; the first +vessel is, of course, charged with treated lyes. As the liquor acquires +a density of 42° Tw. (25° B.) salt begins to deposit, and may be +withdrawn into one of the many patented appliances, in which it is freed +from glycerine, washed and dried ready for use at the soap pans. +Difficulty is sometimes experienced with the tubes becoming choked with +salt, thereby diminishing and retarding evaporation. It may be necessary +to dissolve the encrusted salt with lyes or water, but with careful +working the difficulty can be obviated by washing out with weak lyes +after each batch of crude glycerine has been run away, or by increasing +the circulation. + +It is claimed that by the use of the revolving heater designed by +Lewkowitsch, the salting up of tubes is prevented. + +The salt having been precipitated and removed, evaporation is continued +until a sample taken from the last vessel has a density of 60° Tw. (33.3 +B.) at 60° F. (15.5° C.). When this point is reached, the crude +glycerine is ready to be withdrawn into a tank, and, after allowing the +excess of salt to deposit, may be transferred to the storage tank. + +The colour of crude glycerine varies from light brown to dark brown, +almost black, and depends largely on the materials used for soap-making. +The organic matter present in good crude glycerine is small in amount, +often less than 1 per cent.; arsenic, sulphides and sulphites should be +absent. Crude glycerine is refined in some cases by the producers +themselves; others sell it to firms engaged more particularly in the +refined glycerine trade. + +_Distillation._--Crude glycerine is distilled under vacuum with the aid +of superheated steam. The still is heated directly with a coal or coke +fire, and in this fire space is the superheater, which consists of a +coil of pipes through which high pressure steam from the boiler is +superheated. + +The distillation is conducted at a temperature of 356°F. (180° C.). To +prevent the deposition and burning of salt on the still-bottom during +the distillation, a false bottom is supported about 1 foot from the base +of the still. With the same object in view, it has been suggested to +rotate the contents with an agitator fixed in the still. + +Every care is taken that the still does not become overheated; this +precaution not only prevents loss of glycerine through carbonisation, +but also obviates the production of tarry and other bodies which might +affect the colour, taste, and odour of the distilled glycerine. The +vacuum to be used will, of course, depend upon the heat of the fire and +still, but as a general rule good results are obtained with an 18 inch +vacuum. + +There are quite a large number of designs for still heads, and +"catch-alls," having for their object the prevention of loss of +glycerine. + +The distillate passes into a row of condensers, to each of which is +attached a receptacle or receiver. It is needless to state that the +condensing capacity should be in excess of theoretical requirements. The +fractions are of varying strengths and quality; that portion, with a +density less than 14° Tw. (19.4° B.), is returned to the treated-lyes +tank. The other portion of the distillate is concentrated by means of a +dry steam coil in a suitable vessel under a 28 inch vacuum. + +When sufficiently concentrated the glycerine may be decolorised, if +necessary, by treating with 1 per cent. animal charcoal and passing +through a filter press, from which it issues as "dynamite glycerine". + +The residue in the still, consisting of 50-60 per cent. glycerine and +varying proportions of various sodium salts--_e.g._ acetate, chloride, +sulphate, and combinations with non-volatile organic acids--is generally +boiled with water and treated with acid. + +The tar, which is separated, floats on the surface as the liquor is +cooling, and may be removed by ladles, or the whole mixed with waste +charcoal, and filtered. + +The filtrate is then evaporated, when the volatile organic acids are +driven off; the concentrated liquor is finally mixed with crude +glycerine which is ready for distillation, or it may be distilled +separately. + +_Distilled Glycerine._--This class of commercial glycerine, although of +limited use in various other branches of industry, finds its chief +outlet in the manufacture of explosives. + +Specifications are usually given in contracts drawn up between buyers +and sellers, to which the product must conform. + +The chief stipulation for dynamite glycerine is its behaviour in the +nitration test. When glycerine is gradually added to a cold mixture of +strong nitric and sulphuric acids, it is converted into nitro-glycerine, +which separates as an oily layer on the surface of the acid. The more +definite and rapid the separation, the more suitable is the glycerine +for dynamite-making. + +Dynamite glycerine should be free from arsenic, lime, chlorides, and +fatty acids, the inorganic matter should not amount to more than 0.1 per +cent., and a portion diluted and treated with nitrate of silver solution +should give no turbidity or discoloration in ten minutes. The specific +gravity should be 1.262 at 15° C. (59° F.) and the colour somewhat +yellow. + +_Chemically pure glycerine_ or double distilled glycerine is produced by +redistilling "once distilled" glycerine. Every care is taken to avoid +all fractions which do not withstand the nitrate of silver test. The +distillation is very carefully performed under strict supervision. + +The distillate is concentrated and after treatment with animal charcoal +and filtration should conform to the requirements of the British +Pharmacopoeia. These are specified as follows: Specific gravity at +15.5° C., 1.260. It should yield no characteristic reaction with the +tests for lead, copper, arsenium, iron, calcium, potassium, sodium, +ammonium, chlorides, or sulphates. It should contain no sugars and leave +no residue on burning. + +_Animal Charcoal for Decolorisation._--The application of animal +charcoal for decolorising purposes dates back a century, and various are +the views that have been propounded to explain its action. Some +observers base it upon the physical condition of the so-called carbon +present, and no doubt this is an important factor, coupled with the +porosity. Others consider that the nitrogen, which is present in all +animal charcoal and extremely difficult to remove, is essential to the +action. Animal charcoal should be freed from gypsum (sulphate of lime), +lest in the burning, sulphur compounds be formed which would pass into +the glycerine and contaminate it. + +The "char" should be well boiled with water, then carbonate of soda or +caustic soda added in sufficient quantity to give an alkaline reaction, +and again well boiled. The liquor is withdrawn and the charcoal washed +until the washings are no longer alkaline. The charcoal is then +separated from the liquor and treated with hydrochloric acid; opinions +differ as to the amount of acid to be used. Some contend that phosphate +of lime plays such an important part in decolorising that it should not +be removed, but it has, however, been demonstrated that this substance +after exposure to heat has very little decolorising power. + +Animal charcoal boiled with four times its weight of a mixture +consisting of equal parts of commercial hydrochloric acid (free from +arsenic) and water for twelve hours, then washed free from acid, dried, +and burned in closed vessels gives a product possessed of great +decolorising power for use with glycerines. + +A good animal charcoal will have a dull appearance, and be of a deep +colour; it should be used in fine grains and not in the form of a +powder. + +The charcoal from the filter presses is washed free from glycerine +(which is returned to the treated lyes), cleansed from foreign +substances by the above treatment and revivified by carefully heating in +closed vessels for twelve hours. + +_Glycerine obtained by other Methods of Saponification._--French +saponification or "candle crude" glycerine is the result of +concentration of "sweet water" produced in the manufacture of stearine +and by the autoclave process. It contains 85-90 per cent. glycerol, +possesses a specific gravity of 1.240-1.242, and may be readily +distinguished from the soap-crude glycerine by the absence of salt +(sodium chloride). This glycerine is easily refined by treatment with +charcoal. + +The glycerine water resulting from acid saponification methods requires +to be rendered alkaline by the addition of lime--the sludge is +separated, and the liquor evaporated to crude. The concentration may be +performed in two stages--first to a density of 32° Tw. (20° B.), when +the calcium sulphate is allowed to deposit, and the separated liquor +concentrated to 48° Tw. (28° B.) glycerine, testing 85 per cent. +glycerol and upwards. + +_Yield of Glycerine from Fats and Oils._--The following represent +practicable results which should be obtained from the various +materials:-- + + Tallow 9 per cent. of 80 per cent. Glycerol. + Cotton-seed oil 10 " + Cocoa-nut oil 12 " + Palm-kernel oil 18 " + Olive oil 10 " + Palm oil 6 " + Greases (Bone fats) 6-8 " + +The materials vary in glycerol content with the methods of preparation; +especially is this the case with tallows and greases. + +Every care should be taken that the raw materials are fresh and they +should be carefully examined to ascertain if any decomposition has taken +place in the glycerides--this would be denoted by the presence of an +excess of free acidity, and the amount of glycerol obtainable from such +a fat would be correspondingly reduced. + + + + +CHAPTER X. + +ANALYSIS OF RAW MATERIALS, SOAP, AND GLYCERINE. + + _Fats and Oils--Alkalies and Alkali Salts--Essential + Oils--Soap--Lyes--Crude Glycerine._ + + +_Raw Materials._--Average figures have already been given in Chapters +III. and VIII. for the more important physical and chemical +characteristics of fats and oils, also of essential oils; the following +is an outline of the processes usually adopted in their determination. +For fuller details, text-books dealing exhaustively with the respective +subjects should be consulted. + + +FATS AND OILS. + +It is very undesirable that any of these materials should be allowed to +enter the soap pan without an analysis having first been made, as the +oil may not only have become partially hydrolysed, involving a loss of +glycerine, or contain albuminous matter rendering the soap liable to +develop rancidity, but actual sophistication may have taken place. Thus +a sample of tallow recently examined by the authors contained as much as +40 per cent. of an unsaponifiable wax, which would have led to disaster +in the soap pan, had the bulk been used without examination. After +observing the appearance, colour, and odour of the sample, noting any +characteristic feature, the following physical and chemical data should +be determined. + +_Specific Gravity at 15° C._ This may be taken by means of a Westphal +balance, or by using a picnometer of either the ordinary gravity bottle +shape, with perforated stopper, or the Sprengel U-tube. The picnometer +should be calibrated with distilled water at 15° C. The specific gravity +of solid fats may be taken at an elevated temperature, preferably that +of a boiling water bath. + +_Free acidity_ is estimated by weighing out from 2 to 5 grammes of the +fat or oil, dissolving in neutral alcohol (purified methylated spirit) +with gentle heat, and titrating with a standard aqueous or alcoholic +solution of caustic soda or potash, using phenol-phthalein as indicator. + +The contents of the flask are well shaken after each addition of alkali, +and the reaction is complete when the slight excess of alkali causes a +permanent pink coloration with the indicator. The standard alkali may be +N/2, N/5, or N/10. + +It is usual to calculate the result in terms of oleic acid (1 c.c. N/10 +alkali = 0.0282 gramme oleic acid), and express in percentage on the fat +or oil. + +_Example._--1.8976 grammes were taken, and required 5.2 c.c. of N/10 KOH +solution for neutralisation. + + 5.2 × 0.0282 × 100 + ------------------ = 7.72 per cent. free fatty acids, + 1.8976 expressed as oleic acid. + +The free acidity is sometimes expressed as _acid value_, which is the +amount of KOH in milligrammes necessary to neutralise the free acid in 1 +gramme of fat or oil. + +In the above example:-- + + 5.2 × 5.61 + ---------- = 15.3 acid value. + 1.8976 + +The _saponification equivalent_ is determined by weighing 2-4 grammes of +fat or oil into a wide-necked flask (about 250 c.c. capacity), adding 30 +c.c. neutral alcohol, and warming under a reflux condenser on a steam or +water-bath. When boiling, the flask is disconnected, 50 c.c. of an +approximately semi-normal alcoholic potash solution carefully added from +a burette, together with a few drops of phenol-phthalein solution, and +the boiling under a reflux condenser continued, with frequent agitation, +until saponification is complete (usually from 30-60 minutes) which is +indicated by the absence of fatty globules. The excess of alkali is +titrated with N/1 hydrochloric or sulphuric acid. + +The value of the approximately N/2 alkali solution is ascertained by +taking 50 c.c. together with 30 c.c. neutral alcohol in a similar flask, +boiling for the same length of time as the fat, and titrating with N/1 +hydrochloric or sulphuric acid. The "saponification equivalent" is the +amount of fat or oil in grammes saponified by 1 equivalent or 56.1 +grammes of caustic potash. + +_Example._--1.8976 grammes fat required 18.95 c.c. N/1 acid to +neutralise the unabsorbed alkali. + +Fifty c.c. approximately N/2 alcoholic potash solution required 25.6 +c.c. N/ acid.. + + 25.6 - 18.95 = 6.65 c.c. N/1 KOH required by fat. + + 1.8976 × 1000 / 6.65 = 285.3 Saponification Equivalent. + +The result of this test is often expressed as the "Saponification +Value," which is the number of milligrammes of KOH required for the +saponification of 1 gramme of fat. This may be found by dividing 56,100 +by the saponification equivalent or by multiplying the number of c.c. of +N/1 alkali absorbed, by 56.1 and dividing by the quantity of fat taken. +Thus, in the above example:-- + + 6.65 × 56.1 / 1.8976 = 196.6 Saponification Value. + +The _ester_ or _ether value_, or number of milligrammes of KOH required +for the saponification of the neutral esters or glycerides in 1 gramme +of fat, is represented by the difference between the saponification and +acid values. In the example given, the ester value would be 196.6 - 15.3 += 181.3. + +_Unsaponifiable Matter._--The usual method adopted is to saponify about +5 grammes of the fat or oil with 50 c.c. of approximately N/2 alcoholic +potash solution by boiling under a reflux condenser with frequent +agitation for about 1 hour. The solution is then evaporated to dryness +in a porcelain basin over a steam or water-bath, and the resultant soap +dissolved in about 200 c.c. hot water. When sufficiently cool, the soap +solution is transferred to a separating funnel, 50 c.c. of ether added, +the whole well shaken, and allowed to rest. The ethereal layer is +removed to another separator, more ether being added to the aqueous soap +solution, and again separated. The two ethereal extracts are then washed +with water to deprive them of any soap, separated, transferred to a +flask, and the ether distilled off upon a water-bath. The residue, dried +in the oven at 100° C. until constant, is the "unsaponifiable matter," +which is calculated to per cent. on the oil. + +In this method, it is very frequently most difficult to obtain a +distinct separation of ether and aqueous soap solution--an intermediate +layer of emulsion remaining even after prolonged standing, and various +expedients have been recommended to overcome this, such as addition of +alcohol (when petroleum ether is used), glycerine, more ether, water, or +caustic potash solution, or by rotatory agitation. + +A better plan is to proceed as in the method above described as far as +dissolving the resulting soap in 200 c.c. water, and then boil for +twenty or thirty minutes. Slightly cool and acidify with dilute +sulphuric acid (1 to 3), boil until the fatty acids are clear, wash with +hot water free from mineral acid, and dry by filtering through a hot +water funnel. + +Two grammes of the fatty acids are now dissolved in neutral alcohol +saturated with some solvent, preferably a light fraction of benzoline, a +quantity of the solvent added to take up the unsaponifiable matter, and +the whole boiled under a reflux condenser. After cooling, the liquid is +titrated with N/2 aqueous KOH solution, using phenol-phthalein as +indicator, this figure giving the amount of the total fatty acids +present. The whole is then poured into a separating funnel, when +separation immediately takes place. The alcoholic layer is withdrawn, +the benzoline washed with warm water (about 32° C.) followed by neutral +alcohol (previously saturated with the solvent), and transferred to a +tared flask, which is attached to a condenser, and the benzoline +distilled off. The last traces of solvent remaining in the flask are +removed by gently warming in the water-oven, and the flask cooled and +weighed, thus giving the amount of unsaponifiable matter. + +_Constitution of the Unsaponifiable Matter._--Unsaponifiable matter may +consist of cholesterol, phytosterol, solid alcohols (cetyl and ceryl +alcohols), or hydrocarbons (mineral oil). Cholesterol is frequently +found in animal fats, and phytosterol is a very similar substance +present in vegetable fats. Solid alcohols occur naturally in sperm oil, +but hydrocarbons, which may be generally recognised by the fluorescence +or bloom they give to the oil, are not natural constituents of animal or +vegetable oils and fats. + +The presence of cholesterol and phytosterol may be detected by +dissolving a small portion of the unsaponifiable matter in acetic +anhydride, and adding a drop of the solution to one drop of 50 per cent. +sulphuric acid on a spot plate, when a characteristic blood red to +violet coloration is produced. It has been proposed to differentiate +between cholesterol and phytosterol by their melting points, but it is +more reliable to compare the crystalline forms, the former crystallising +in laminæ, while the latter forms groups of needle-shaped tufts. Another +method is to convert the substance into acetate, and take its melting +point, cholesterol acetate melting at 114.3-114.8° C., and phytosterol +acetate at 125.6°-137° C. + +Additional tests for cholesterol have been recently proposed by +Lifschütz (_Ber. Deut. Chem. Ges._, 1908, 252-255), and Golodetz (_Chem. +Zeit._, 1908, 160). In that due to the former, which depends on the +oxidation of cholesterol to oxycholesterol ester and oxycholesterol, a +few milligrammes of the substance are dissolved in 2-3 c.c. glacial +acetic acid, a little benzoyl peroxide added, and the solution boiled, +after which four drops of strong sulphuric acid are added, when a +violet-blue or green colour is produced, if cholesterol is present, the +violet colour being due to oxycholesterol ester, the green to +oxycholesterol. Two tests are suggested by Golodetz (1) the addition of +one or two drops of a reagent consisting of five parts of concentrated +sulphuric acid and three parts of formaldehyde solution, which colours +cholesterol a blackish-brown, and (2) the addition of one drop of 30 per +cent. formaldehyde solution to a solution of the substance in +trichloracetic acid, when with cholesterol an intense blue coloration is +produced. + +_Water._--From 5 to 20 grammes of the fat or oil are weighed into a +tared porcelain or platinum dish, and stirred with a thermometer, whilst +being heated over a gas flame at 100° C. until bubbling or cracking has +ceased, and reweighed, the loss in weight representing the water. In +cases of spurting a little added alcohol will carry the water off +quietly. + +To prevent loss by spurting, Davis (_J. Amer. Chem. Soc._, 23, 487) has +suggested that the fat or oil should be added to a previously dried and +tared coil of filter paper contained in a stoppered weighing bottle, +which is then placed in the oven and dried at 100° C. until constant in +weight. Of course, this method is not applicable to oils or fats liable +to oxidation on heating. + +_Dregs, Dirt, Adipose Tissue, Fibre, etc._--From 10 to 15 grammes of the +fat are dissolved in petroleum ether with frequent stirring, and passed +through a tared filter paper. The residue retained by the filter paper +is washed with petroleum ether until free from fat, dried in the +water-oven at 100° C. and weighed. + +If the amount of residue is large, it may be ignited, and the proportion +and nature of the ash determined. + +The amount of impurities may also be estimated by Tate's method, which +is performed by weighing 5 grammes of fat into a separating funnel, +dissolving in ether, and allowing the whole to stand to enable the water +to deposit. After six hours' rest the water is withdrawn, the tube of +the separator carefully dried, and the ethereal solution filtered +through a dried tared filter paper into a tared flask. Well wash the +filter with ether, and carefully dry at 100° C. The ether in the flask +is recovered, and the flask dried until all ether is expelled, and its +weight is constant. The amount of fat in the flask gives the quantity of +actual fat in the sample taken; the loss represents the water and other +impurities, and these latter may be obtained from the increase of weight +of the filter paper. + +_Starch_ may be detected by the blue coloration it gives with iodine +solution, and confirmed by microscopical examination, or it may be +converted into glucose by inversion, and the glucose estimated by means +of Fehling's solution. + +_Iodine Absorption._--This determination shows the amount of iodine +absorbed by a fat or oil, and was devised by Hübl, the reagents required +being as follows:-- + +(1) Solution of 25 grammes iodine in 500 c.c. absolute alcohol; (2) +solution of 30 grammes mercuric chloride in 500 c.c. absolute alcohol, +these two solutions being mixed together and allowed to stand at least +twelve hours before use; (3) a freshly prepared 10 per cent. aqueous +solution of potassium iodide; and (4) a N/10 solution of sodium +thiosulphate, standardised just prior to use by titrating a weighed +quantity of resublimed iodine dissolved in potassium iodide solution. + +In the actual determination, 0.2 to 0.5 gramme of fat or fatty acids is +carefully weighed into a well-fitting stoppered 250 c.c. bottle, +dissolved in 10 c.c. chloroform, and 25 c.c. of the Hübl reagent added, +the stopper being then moistened with potassium iodide solution and +placed firmly in the bottle, which is allowed to stand at rest in a dark +place for four hours. A blank experiment is also performed, using the +same quantities of chloroform and Hübl reagent, and allowing to stand +for the same length of time. + +After the expiration of four hours 20 c.c. of 10 per cent. solution of +potassium iodide and 150 c.c. water are added to the contents of the +bottle, and the excess of iodine titrated with N/10 sodium thiosulphate +solution, the whole being well agitated during the titration, which is +finished with starch paste as indicator. The blank experiment is +titrated in the same manner, and from the amount of thiosulphate +required in the blank experiment is deducted the number of c.c. required +by the unabsorbed iodine in the other bottle; this figure multiplied by +the iodine equivalent of 1 c.c. of the thiosulphate solution and by 100, +dividing the product by the weight of fat taken, gives the "Iodine +Number". + +_Example._--1 c.c. of the N/10 sodium thiosulphate solution is found +equal to 0.0126 gramme iodine. + +0.3187 gramme of fat taken. Blank requires 48.5 c.c. thiosulphate. + +Bottle containing oil requires 40.0 c.c. thiosulphate. + +48.5 - 40.0 = 8.5, and the iodine absorption of the fat is-- + + 8.5 × 0.0126 × 100 + ------------------ = 33.6. + 0.3187 + +Wijs showed that by the employment of a solution of iodine monochloride +in glacial acetic acid reliable iodine figures are obtained in a much +shorter time, thirty minutes being sufficient, and this method is now in +much more general use than the Hübl. Wijs' iodine reagent is made by +dissolving 13 grammes iodine in 1 litre of glacial acetic acid and +passing chlorine into the solution until the iodine is all converted +into iodine monochloride. The process is carried out in exactly the same +way as with the Hübl solution except that the fat is preferably +dissolved in carbon tetrachloride instead of in chloroform. + +_Bromine absorption_ has now been almost entirely superseded by the +iodine absorption, although there are several good methods. The +gravimetric method of Hehner (_Analyst_, 1895, 49) was employed by one +of us for many years with very good results, whilst the bromine-thermal +test of Hehner and Mitchell (_Analyst_, 1895, 146) gives rapid and +satisfactory results. More recently MacIlhiney (_Jour. Amer. Chem. +Soc._, 1899, 1084-1089) drew attention to bromine absorption methods and +tried to rewaken interest in them. + +The _Refractive index_ is sometimes useful for discriminating between +various oils and fats, and, in conjunction with other physical and +chemical data, affords another means of detecting adulteration. + +Where a great number of samples have to be tested expeditiously, the +Abbé refractometer or the Zeiss butyro-refractometer may be recommended +on account of the ease with which they are manipulated. The most usual +temperature of observations is 60° C. + +The _Titre_ or setting point of the fatty acids was devised by Dalican, +and is generally accepted in the commercial valuation of solid fats as a +gauge of firmness, and in the case of tallow has a considerable bearing +on the market value. + +One ounce of the fat is melted in a shallow porcelain dish, and 30 c.c. +of a 25 per cent. caustic soda solution added, together with 50 c.c. of +redistilled methylated spirit. The whole is stirred down on the water +bath until a pasty soap is obtained, when another 50 c.c. of methylated +spirit is added, which redissolves the soap, and the whole again stirred +down to a solid soap. This is then dissolved in distilled water, a +slight excess of dilute sulphuric acid added to liberate the fatty +acids, and the whole warmed until the fatty acids form a clear liquid +on the surface. The water beneath the fatty acids is then syphoned off, +more distilled water added to wash out any trace of mineral acid +remaining, and again syphoned off, this process being repeated until the +washings are no longer acid to litmus paper, when the fatty acids are +poured on to a dry filter paper, which is inserted in a funnel resting +on a beaker, and the latter placed on the water-bath, where it is left +until the clear fatty acids have filtered through. + +About 10-15 grammes of the pure fatty acids are now transferred to a +test tube, 6" × 1", warmed until molten, and the tube introduced through +a hole in the cork into a flask or wide-mouthed bottle. A very accurate +thermometer, graduated into fifths of a degree Centigrade (previously +standardised), is immersed in the fatty acids, so that the bulb is as +near the centre as possible, and when the fatty acids just begin to +solidify at the bottom of the tube, the thermometer is stirred round +slowly. The mercury will descend, and stirring is continued until it +ceases to fall further, at which point the thermometer is very carefully +observed. It will be found that the temperature will rise rapidly and +finally remain stationary for a short time, after which it will again +begin to drop until the temperature of the room is reached. The maximum +point to which the temperature rises is known as the "titre" of the +sample. + + +ALKALIES AND ALKALI SALTS. + +Care should be bestowed upon the sampling of solid caustic soda or +potash as the impurities during the solidification always accumulate in +the centre of the drum, and an excess of that portion must be avoided or +the sample will not be sufficiently representative. The sampling should +be performed expeditiously to prevent carbonating, and portions placed +in a stoppered bottle. The whole should be slightly broken in a mortar, +and bright crystalline portions taken for analysis, using a stoppered +weighing bottle. + +_Caustic Soda and Caustic Potash._--These substances are valued +according to the alkali present in the form of caustic (hydrate) and +carbonate. + +About 2 grammes of the sample are dissolved in 50 c.c. distilled water, +and titrated with N/1 sulphuric acid, using phenol-phthalein as +indicator, the alkalinity so obtained representing all the caustic +alkali and one-half the carbonate, which latter is converted into +bicarbonate. One c.c. N/1 acid = 0.031 gramme Na_{2}O or 0.040 gramme +NaOH and 0.047 gramme K_{2}O, or 0.056 gramme KOH. + +After this first titration, the second half of the carbonate may be +determined in one of two ways, either:-- + +(1) By adding from 3-5 c.c. of N/10 acid, and well boiling for five +minutes to expel carbonic-acid gas, after which the excess of acid is +titrated with N/10 soda solution; or + +(2) After adding two drops of methyl orange solution, N/10 acid is run +in until the solution acquires a faint pink tint. + +In the calculation of the caustic alkali, the number of c.c. of acid +required in the second titration, divided by 10, is subtracted from that +used in the first, and this difference multiplied by 0.031, or 0.047 +gives the amount of Na_{2}O or K_{2}O respectively in the weight of +sample taken, whence the percentage may be readily calculated. + +The proportion of carbonate is calculated by multiplying the amount of +N/10 acid required in the second titration by 2, and then by either +0.0031 or 0.0047 to give the amount of carbonate present, expressed as +Na_{2}O or K_{2}O respectively. + +An alternative method is to determine the alkalinity before and after +the elimination of carbonate by chloride of barium. + +About 7-8 grammes of the sample are dissolved in water, and made up to +100 c.c., and the total alkalinity determined by titrating 20 c.c. with +N/1 acid, using methyl orange as indicator. To another 20 c.c. is added +barium chloride solution (10 per cent.) until it ceases to give a +precipitate, the precipitate allowed to settle, and the clear +supernatant liquid decanted off, the precipitate transferred to a filter +paper and well washed, and the filtrate titrated with N/1 acid, using +phenol-phthalein as indicator. The second titration gives the amount of +caustic alkali present, and the difference between the two the +proportion of carbonate. + +When methyl orange solution is used as indicator, titrations must be +carried out cold. + +Reference has already been made (p. 39) to the manner in which the +alkali percentage is expressed in English degrees in the case of caustic +soda. + +_Chlorides_ are estimated by titrating the neutral solution with N/10 +silver nitrate solution, potassium chromate being used as indicator. One +c.c. N/10 AgNO_{3} solution = 0.00585 gramme sodium chloride. + +The amount of acid necessary for exact neutralisation having already +been ascertained, it is recommended to use the equivalent quantity of +N/10 nitric acid to produce the neutral solution. + +_Sulphides_ may be tested for, qualitatively, with lead acetate +solution. + +_Aluminates_ are determined gravimetrically in the usual manner; 2 +grammes are dissolved in water, rendered acid with HCl, excess of +ammonia added, and the gelatinous precipitate of aluminium hydrate +collected on a filter paper, washed, burnt, and weighed. + + * * * * * + +_Carbonated Alkali (Soda Ash)._--The total or available alkali is, of +course, the chief factor to be ascertained, and for this purpose it is +convenient to weigh out 3.1 grammes of the sample, dissolve in 50 c.c. +water, and titrate with N/1 sulphuric or hydrochloric acid, using methyl +orange as indicator. Each c.c. of N/1 acid required represents 1 per +cent. Na_{2}O in the sample under examination. + +A more complete analysis of soda ash would comprise:-- + +_Insoluble matter_, remaining after 10 grammes are dissolved in warm +water. This is washed on to a filter-paper, dried, ignited, and weighed. + +The filtrate is made up to 200 c.c., and in it may be determined:-- + +_Caustic soda_, by titrating with N/1 acid the filtrate resulting from +the treatment of 20 c.c. (equal to 1 gramme) with barium chloride +solution. + +_Carbonate._--Titrate 20 c.c. with N/1 acid, and deduct the amount of +acid required for the Caustic. + +_Chlorides._--Twenty c.c. are exactly neutralised with nitric acid, +titrated with N/10 AgNO_{3} solution, using potassium chromate as +indicator. + +_Sulphates._--Twenty c.c. are acidulated with HCl, and the sulphates +precipitated with barium chloride; the precipitate is collected on a +filter paper, washed, dried, ignited, and weighed, the result being +calculated to Na_{2}SO_{4}. + +_Sulphides and Sulphites._--The presence of these compounds is denoted +by the evolution of sulphuretted hydrogen and sulphurous acid +respectively when the sample is acidulated. Sulphides may also be tested +for, qualitatively, with lead acetate solution, or test-paper of sodium +nitro-prusside. + +The total quantity of these compounds may be ascertained by acidulating +with acetic acid, and titrating with N/10 iodine solution, using starch +paste as indicator. One c.c. N/10 iodine solution = 0.0063 gramme +Na_{2}SO_{3}. + +The amount of sulphides may be estimated by titrating the hot soda +solution, to which ammonia has been added, with an ammoniacal silver +nitrate solution, 1 c.c. of which corresponds to 0.005 gramme Na_{2}S. +As the titration proceeds, the precipitate is filtered off, and the +addition of ammoniacal silver solution to the filtrate continued until a +drop produces only a slight opacity. The presence of chloride, sulphate, +hydrate, or carbonate does not interfere with the accuracy of this +method. The ammoniacal silver nitrate solution is prepared by dissolving +13.345 grammes of pure silver in pure nitric acid, adding 250 c.c. +liquor ammoniæ fortis, and diluting to 1 litre. + +_Carbonate of Potash (Pearl Ash)._--The total or available alkali may be +estimated by taking 6.9 grammes of the sample, and titrating with N/1 +acid directly, or adding 100 c.c. N/1 sulphuric acid, boiling for a few +minutes, and titrating the excess of acid with N/1 caustic soda +solution, using litmus as indicator. In this case each c.c. N/1 acid +required, is equivalent, in the absence of Na_{2}CO_{3}, to 1 per cent. +K_{2}CO_{3}. + +Carbonate of potash may be further examined for the following:-- + +_Moisture._--From 2-3 grammes are heated for thirty minutes in a +crucible over a gas flame, and weighed when cold, the loss in weight +representing the moisture. + +_Insoluble residue_, remaining after solution in water, filtering and +well washing. + +_Potassium_ may be determined by precipitation as potassium +platino-chloride thus:--Dissolve 0.5 gramme in a small quantity (say 10 +c.c.) of water, and carefully acidulate with hydrochloric acid, +evaporate the resultant liquor to dryness in a tared platinum basin, and +heat the residue gradually to dull redness. Cool in a desicator, weigh, +and express the result as "mixed chlorides," _i.e._ chlorides of soda +and potash. To the mixed chlorides add 10 c.c. water, and platinic +chloride in excess (the quantity may be three times the amount of the +mixed chlorides) and evaporate nearly to dryness; add 15 c.c. alcohol +and allow to stand three hours covered with a watch-glass, giving the +dish a gentle rotatory movement occasionally. The clear liquid is +decanted through a tared filter, and the precipitate well washed with +alcohol by decantation, and finally transferred to the filter, dried and +weighed. From the weight of potassium platino-chloride, K_{2}PtCl_{6}, +is calculated the amount of potassium oxide K_{2}O by the use of the +factor 94/488.2 or 0.19254. + +_Chlorides_, determined with N/10 silver nitrate solution, and +calculated to KCl. + +_Sulphates_, estimated as barium sulphate, and calculated to +K_{2}SO_{4}. + +_Sodium Carbonate_, found by deducting the K_{2}CO_{3} corresponding to +the actual potassium as determined above, from the total alkali. + +_Iron_, precipitated with excess of ammonia, filtered, ignited, and +weighed as Fe_{2}O_{3}. + + +SODIUM CHLORIDE (COMMON SALT). + +This should be examined for the following:-- + +_Actual Chloride_, either titrated with N/10 silver nitrate solution, +using neutral potassium chromate solution as indicator, or, preferably, +estimated gravimetrically as silver chloride by precipitation with +silver nitrate solution, the precipitate transferred to a tared filter +paper, washed, dried and weighed. + +_Insoluble matter_, remaining on dissolving 5 grammes in water, and +filtering. This is washed, dried, ignited and weighed. + +_Moisture._--5 grammes are weighed into a platinum crucible, and heat +gently applied. The temperature is gradually increased to a dull red +heat, which is maintained for a few minutes, the dish cooled in a +desicator, and weighed. + +_Sulphates_ are estimated by precipitation as barium sulphate and +calculated to Na_{2}SO_{4}. + +_Sodium._--This may be determined by converting the salt into sodium +sulphate by the action of concentrated sulphuric acid, igniting to drive +off hydrochloric and sulphuric acids, and fusing the mass until constant +in weight, weighing finally as Na_{2}SO_{4}. + + +POTASSIUM CHLORIDE. + +This should be examined, in the same way as sodium chloride, for +chloride, insoluble matter, moisture, and sulphate. The potassium may be +determined as potassium platino-chloride, as described under carbonate +of potash. + + +SILICATES OF SODA AND POTASH. + +The most important determinations for these are total alkali and silica. + +_Total alkali_ is estimated by dissolving 2 grammes in distilled water, +and titrating when cold, with N/1 acid, using methyl orange as +indicator. + +_Silica_ may be determined by dissolving 1 gramme in distilled water, +rendering the solution acid with HCl, and evaporating to complete +dryness on the water-bath, after which the residue is moistened with HCl +and again evaporated, this operation being repeated a third time. The +residue is then heated to about 150° C., extracted with hot dilute HCl, +filtered, thoroughly washed, dried, ignited in a tared platinum +crucible, and weighed as SiO_{2}. + + +ESSENTIAL OILS. + +As already stated, these are very liable to adulteration, and an +examination of all kinds of oil is desirable, while in the case of the +more expensive varieties it should never be omitted. + +_Specific Gravity._--As with fats and oils, this is usually taken at 15° +C., and compared with water at the same temperature. In the case of otto +of rose and guaiac wood oil, however, which are solid at this +temperature, it is generally observed at 30° C. compared with water at +15° C. + +The specific gravity is preferably taken in a bottle or U-tube, but if +sufficient of the oil is available and a high degree of accuracy is not +necessary, it may be taken either with a Westphal balance, or by means +of a hydrometer. + +_Optical Rotation._--For this purpose a special instrument, known as a +polarimeter, is required, details of the construction and use of which +would be out of place here. Suffice it to mention that temperature plays +an important part in the determination of the optical activity of +certain essential oils, notably in the case of lemon and orange oils. +For these Gildemeister and Hoffmann give the following corrections:-- + +Lemon oil, below 20° C. subtract 9' for each degree below, above 20° C. +add 8' for each degree above. + +Orange oil, below 20° C. subtract 14' for each degree below, above 20° +C. add 13' for each degree above. + +_Refractive Index._--This figure is occasionally useful, and is best +determined with an Abbé refractometer, at 20° C. + +_Solubility in Alcohol._--This is found by running alcohol of the +requisite strength from a burette into a measured volume of the oil with +constant agitation, until the oil forms a clear solution with the +alcohol. Having noted the quantity of alcohol added, it is well to run +in a small further quantity of alcohol, and observe whether any +opalescence or cloudiness appears. + +_Acid_, _ester_, and _saponification values_ are determined exactly as +described under fats and oils. Instead of expressing the result as +saponification value or number, the percentage of ester, calculated in +the form of the most important ester present, may be obtained by +multiplying the number of c.c. of N/1 alkali absorbed in the +saponification by the molecular weight of the ester. Thus, to find the +percentage as linalyl acetate, the number of c.c. absorbed would be +multiplied by 0.196 and by 100, and divided by the weight of oil taken. + +_Alcohols._--For the estimation of these, if the oil contains much ester +it must first be saponified with alcoholic potash, to liberate the +combined alcohols, and after neutralising the excess of alkali with +acid, the oil is washed into a separating funnel with water, separated, +dried with anhydrous sodium sulphate, and is then ready for the alcohol +determination. + +If there is only a small quantity of ester present, this preliminary +saponification is unnecessary. + +The alcohols are estimated by conversion into their acetic esters, which +are then saponified with standard alcoholic potash, thereby furnishing a +measure of the amount of alcohol esterified. + +Ten c.c. of the oil is placed in a flask with an equal volume of acetic +anhydride, and 2 grammes of anhydrous sodium acetate, and gently boiled +for an hour to an hour and a half. After cooling, water is added, and +the contents of the flask heated on the water-bath for fifteen to thirty +minutes, after which they are cooled, transferred to a separating +funnel, and washed with a brine solution until the washings cease to +give an acid reaction with litmus paper. The oil is now dried with +anhydrous sodium sulphate, filtered, and 1-2 grammes weighed into a +flask and saponified with alcoholic potash as in the determination of +ester or saponification value. + +The calculation is a little complicated, but an example may perhaps +serve to make it clear. + +A geranium oil containing 26.9 per cent. of ester, calculated as geranyl +tiglate, was acetylated, after saponification, to liberate the combined +geraniol, and 2.3825 grammes of the acetylated oil required 9.1 c.c. of +N/1 alkali for its saponification. + +Now every 196 grammes of geranyl acetate present in the acetylated oil +correspond to 154 grammes of geraniol, so that for every 196 grammes of +ester now present in the oil, 42 grammes have been added to its weight, +and it is therefore necessary to make a deduction from the weight of oil +taken for the final saponification to allow for this, and since each +c.c. of N/1 alkali absorbed corresponds to 0.196 gramme of geranyl +acetate, the amount to be deducted is found by multiplying the number of +c.c. absorbed by 0.042 gramme, the formula for the estimation of total +alcohols thus becoming in the example given:-- + + 9.1 × 0.154 × 100 + Per cent. of geraniol = ---------------------- = 70.2 + 2.3825 - (9.1 × 0.042) + +The percentage of combined alcohols can be calculated from the amount of +ester found, and by subtracting this from the percentage of total +alcohols, that of the free alcohols is obtained. + +In the example quoted, the ester corresponds to 17.6 per cent. geraniol, +and this, deducted from the total alcohols, gives 52.6 per cent. free +alcohols, calculated as geraniol. + +This process gives accurate results with geraniol, borneol, and menthol, +but with linalol and terpineol the figures obtained are only +comparative, a considerable quantity of these alcohols being decomposed +during the acetylation. The aldehyde citronellal is converted by acetic +anhydride into isopulegol acetate, so that this is also included in the +determination of graniol in citronella oil. + +_Phenols._--These bodies are soluble in alkalies, and may be estimated +by measuring 5 c.c. or 10 c.c. of the oil into a Hirschsohn flask (a +flask of about 100 c.c. capacity with a long narrow neck holding 10 +c.c., graduated in tenths of a c.c.), adding 25 c.c. of a 5 per cent. +aqueous caustic potash solution, and warming in the water-bath, then +adding another 25 c.c., and after one hour in the water-bath filling the +flask with the potash solution until the unabsorbed oil rises into the +neck of the flask, the volume of this oil being read off when it has +cooled down to the temperature of the laboratory. From the volume of oil +dissolved the percentage of phenols is readily calculated. + +_Aldehydes._--In the estimation of these substances, use is made of +their property of combining with sodium bisulphite to form compounds +soluble in hot water. From 5-10 c.c. of the oil is measured into a +Hirschsohn flask, about 30 c.c. of a hot saturated solution of sodium +bisulphite added, and the flask immersed in a boiling water bath, and +thoroughly shaken at frequent intervals. Further quantities of the +bisulphite solution are gradually added, until, after about one hour, +the unabsorbed oil rises into the neck of the flask, where, after +cooling, its volume is read off, and the percentage of absorbed oil, or +aldehydes, calculated. + +In the case of lemon oil, where the proportion of aldehydes, though of +great importance, is relatively very small, it is necessary to first +concentrate the aldehydes before determining them. For this purpose, 100 +c.c. of the oil is placed in a Ladenburg fractional distillation flask, +and 90 c.c. distilled off under a pressure of not more than 40 mm., and +the residue steam distilled. The oil so obtained is separated from the +condensed water, measured, dried, and 5 c.c. assayed for aldehydes +either by the process already described, or by the following process +devised by Burgess (_Analyst_, 1904, 78):-- + +Five c.c. of the oil are placed in the Hirschsohn flask, about 20 c.c. +of a saturated solution of neutral sodium sulphite added, together with +a few drops of rosolic acid solution as indicator, and the flask placed +in a boiling water-bath and continually agitated. The contents of the +flask soon become red owing to the liberation of free alkali by the +combination of the aldehyde with part of the sodium sulphite, and this +coloration is just discharged by the addition of sufficient 10 per +cent. acetic-acid solution. The flask is again placed in the water-bath, +the shaking continued, and any further alkali liberated neutralised by +more acetic acid, the process being continued in this way until no +further red colour is produced. The flask is then filled with the sodium +sulphite solution, the volume of the cooled unabsorbed oil read off, and +the percentage of aldehydes calculated as before. + +_Solidifying Point, or Congealing Point._--This is of some importance in +the examination of anise and fennel oils, and is also useful in the +examination of otto of rose. A suitable apparatus may be made by +obtaining three test tubes, of different sizes, which will fit one +inside the other, and fixing them together in this way through corks. +The innermost tube is then filled with the oil, and a sensitive +thermometer, similar to that described under the Titre test for fats, +suspended with its bulb completely immersed in the oil. With anise and +fennel, the oil is cooled down with constant stirring until it just +starts crystallising, when the stirring is interrupted, and the maximum +temperature to which the mercury rises noted. This is the solidifying +point. + +In the case of otto of rose, the otto is continually stirred, and the +point at which the first crystal is observed is usually regarded as the +congealing point. + +_Melting Point._--This is best determined by melting some of the solid +oil, or crystals, and sucking a small quantity up into a capillary tube, +which is then attached by a rubber band to the bulb of the thermometer, +immersed in a suitable bath (water, glycerine, oil, etc.) and the +temperature of the bath gradually raised until the substance in the tube +is sufficiently melted to rise to the surface, the temperature at which +this takes place being the melting point. + +The melting point of otto of rose is usually taken in a similar tube to +the setting point, and is considered to be the point at which the last +crystal disappears. + +_Iodine Absorption._--In the authors' opinion, this is of some value in +conjunction with other data in judging of the purity of otto of rose. It +is determined by Hübl's process as described under Fats and Oils, except +that only 0.1 to 0.2 gramme is taken, and instead of 10 c.c. of +chloroform, 10 c.c. of pure alcohol are added. The rest of the process +is identical. + + +SOAP. + +In the analysis of soap, it is a matter of considerable importance that +all the determinations should be made on a uniform and average sample of +the soap, otherwise very misleading and unreliable figures are obtained. +Soap very rapidly loses its moisture on the surface, while the interior +of the bar or cake may be comparatively moist, and the best way is to +carefully remove the outer edges and take the portions for analysis from +the centre. In the case of a household or unmilled toilet soap, it is +imperative that the quantities for analysis should all be weighed out as +quickly after each other as possible. + +_Fatty Acids._--Five grammes of the soap are rapidly weighed into a +small beaker, distilled water added, and the beaker heated on the water +bath until the soap is dissolved. + +A slight excess of mineral acid is now added, and the whole heated until +the separated fatty acids are perfectly clear, when they are collected +on a tared filter paper, well washed with hot water and dried until +constant in weight. The result multiplied by 20 gives the percentage of +fatty acids in the sample. + +A quicker method, and one which gives accurate results when care is +bestowed upon it, is to proceed in the manner described above as far as +the decomposition with mineral acid, and to then add 5 or 10 grammes of +stearic acid or beeswax to the contents of the beaker and heat until a +clear layer of fatty matter collects upon the acid liquor. + +Cool the beaker, and when the cake is sufficiently hard, remove it +carefully by means of a spatula and dry on a filtering paper, add the +portions adhering to the sides of the beaker to the cake, and weigh. + +The weight, less the amount of stearic acid or beeswax added, multiplied +by 20 gives the percentage of fatty acids. + +Care must be taken that the cake does not contain enclosed water. + +The results of these methods are returned as fatty acids, but are in +reality insoluble fatty acids, the soluble fatty acids being generally +disregarded. However in soaps made from cocoa-nut and palm-kernel oils +(which contain an appreciable quantity of soluble fatty acids) the acid +liquor is shaken with ether, and, after evaporation of the ethereal +extract, the amount of fatty matter left is added to the result already +obtained as above, or the ether method described below may be +advantageously employed. + +Where the soap under examination contains mineral matter, the separated +fatty acids may be dissolved in ether. This is best performed in an +elongated, graduated, stoppered tube, the total volume of the ether, +after subsidence, carefully read, and an aliquot part taken and +evaporated to dryness in a tared flask, which is placed in the oven at +100° C. until the weight is constant. + +In a complete analysis, the figure for fatty acids should be converted +into terms of fatty anhydrides by multiplying by the factor 0.9875. + +In this test the resin acids contained in the soap are returned as fatty +acids, but the former can be estimated, as described later, and deducted +from the total. + +_Total Alkali._--The best method is to incinerate 5 grammes of the soap +in a platinum dish, dissolve the residue in water, boil and filter, +making the volume of filtrate up to 250 c.c., the solution being +reserved for the subsequent determination of salt, silicates, and +sulphates, as detailed below. + +Fifty c.c. of the solution are titrated with N/1 acid, to methyl orange, +and the result expressed in terms of Na_{2}O. + +Number of c.c. required × 0.031 × 100 = per cent. Na_{2}O. + +The total alkali may also be estimated in the filtrate from the +determination of fatty acids, if the acid used for decomposing the soap +solution has been measured and its strength known, by titrating back the +excess of acid with normal soda solution, when the difference will equal +the amount of total alkali in the quantity taken. + +The total alkali is usually expressed in the case of hard soaps as +Na_{2}O, and in soft soaps as K_{2}O. + +_Free caustic alkali_ is estimated by dissolving 2 grammes of the soap, +in neutral pure alcohol, with gentle heat, filtering, well washing the +filter with hot neutral spirit, and titrating the filtrate with N/10 +acid, to phenol-phthalein. + +Number of c.c. required × 0.0031 × 50 = per cent. free alkali Na_{2}O, +as caustic. + +_Free Carbonated Alkali._--The residue on the filter paper from the +above determination is washed with hot water, and the aqueous filtrate +titrated with N/10 acid, using methyl orange as indicator. The result is +generally expressed in terms of Na_{2}O. + +Number of c.c. required × 0.0031 × 50 = per cent. free alkali Na_{2}O, +as carbonate. + +_Free Alkali._--Some analysts determine the alkalinity to +phenol-phthalein of the alcoholic soap solution without filtering, and +express it as free alkali (caustic, carbonates, or any salt having an +alkaline reaction). + +_Combined Alkali._--The difference between total alkali and free alkali +(caustic and carbonate together) represents the alkali combined with +fatty acids. This figure may also be directly determined by titrating, +with N/2 acid, the alcoholic solution of soap after the free caustic +estimation, using lacmoid as indicator. + +The potash and soda in soaps may be separated by the method described +for the estimation of potassium in _Pearl ash_ (page 126). + +The potassium platino-chloride (K_{2}PtCl_{6}) is calculated to +potassium chloride (KCl) by using the factor 0.3052, and this figure +deducted from the amount of mixed chlorides found, gives the amount of +sodium chloride (NaCl), from which the sodium oxide (Na_{2}O) is +obtained by multiplying by 0.52991. + +The potassium chloride (KCl) is converted into terms of potassium oxide +(K_{2}O) by the use of the factor 0.63087. + +_Salt_ may be determined in 50 c.c. of the filtered aqueous extract of +the incinerated soap, by exactly neutralising with normal acid and +titrating with N/10 silver nitrate solution, using a neutral solution of +potassium chromate as indicator. The final reaction is more distinctly +observed if a little bicarbonate of soda is added to the solution. + +Number of c.c. required × 0.00585 × 100 = per cent. of common salt, +NaCl. + +Chlorides may also be estimated by Volhard's method, the aqueous extract +being rendered slightly acid with nitric acid, a measured volume of N/10 +silver nitrate solution added, and the excess titrated back with N/10 +ammonium thiocyanate solution, using iron alum as indicator. + +_Silicates._--These are estimated by evaporating 50 c.c. of the filtered +extract from the incinerated soap, in a platinum dish with hydrochloric +acid twice to complete dryness, heating to 150° C., adding hot water, +and filtering through a tared filter paper. + +The residue is well washed, ignited, and weighed as SiO_{2}, and from +this silica is calculated the sodium silicate. + +_Sulphates_ may be determined in the filtrate from the silica estimation +by precipitation with barium chloride solution, and weighing the barium +sulphate, after filtering, and burning, expressing the result in terms +of Na_{2}SO_{4} by the use of the factor 0.6094. + +_Moisture._--This is simply estimated by taking a weighed portion in +small shavings in a tared dish, and drying in the oven at 105° C. until +it ceases to lose weight. From the loss thus found is calculated the +moisture percentage. + +_Free or Uncombined Fat._--This is usually determined by repeated +extraction of an aqueous solution of the soap with petroleum ether; the +ethereal solution, after washing with water to remove traces of soap, is +evaporated to dryness and the residue weighed. + +A good method, which can be recommended for employment where many +determinations have to be performed, is to dissolve 10 grammes of soap +in 50 c.c. neutral alcohol and titrate to phenol-phthalein with N/1 +acid. Add 3-5 drops HCl and boil to expel carbonic acid, neutralise with +alcoholic KOH solution and add exactly 10 c.c. in excess, boil for +fifteen minutes under a reflux condenser and titrate with N/1 acid. The +difference between this latter figure and the amount required for a +blank test with 10 c.c. alcoholic KOH, denotes the amount of alkali +absorbed by the uncombined fat. + +_Examination of the fatty acids_ as a guide to the probable composition +of the soap:-- + +From the data obtained by estimating the "titre," iodine number, and +saponification equivalent of the mixed fatty and rosin acids, and the +rosin content, a fairly good idea of the constitution of the soap may be +deduced. + +The titre, iodine number, and saponification equivalent are determined +in exactly the same manner as described under Fats and Oils. + +The presence of rosin may be detected by the Liebermann-Storch reaction, +which consists in dissolving a small quantity of the fatty acids in +acetic anhydride, and adding to a few drops of this solution 1 drop of +50 per cent. sulphuric acid. A violet coloration is produced with rosin +acids. The amount of rosin may be estimated by the method devised by +Twitchell (_Journ. Soc. Chem. Ind._, 1891, 804) which is carried out +thus:-- + +Two grammes of the mixed fatty and rosin acids are dissolved in 20 c.c. +absolute alcohol, and dry hydrochloric acid gas passed through until no +more is absorbed, the flask being kept cool by means of cold water to +prevent the rosin acids being acted upon. The flask, after +disconnecting, is allowed to stand one hour to ensure complete +combination, when its contents are transferred to a Philips' beaker, +well washed out with water so that the volume is increased about five +times, and boiled until the acid solution is clear, a fragment of +granulated zinc being added to prevent bumping. The heat is removed, and +the liquid allowed to cool, when it is poured into a separator, and the +beaker thoroughly rinsed out with ether. After shaking, the acid liquor +is withdrawn, and the ethereal layer washed with water until free from +acid. Fifty c.c. neutral alcohol are added, and the solution titrated +with N/1 KOH or NaOH solution, the percentage of rosin being calculated +from its combining weight. Twitchell suggests 346 as the combining +weight of rosin, but 330 is a closer approximation. + +The method may be also carried out gravimetrically, in which case +petroleum ether, boiling at 74° C. is used for washing out the beaker +into the separator. The acid liquor is run off, and the petroleum ether +layer washed first with water and then with a solution of 1/2 gramme KOH +and 5 c.c. alcohol in 50 c.c. water, and agitated. The rosin is thus +saponified and separated. The resinate solution is withdrawn, acidified, +and the resin acids collected, dried and weighed. + +_Halphen's Reaction._--This is a special test to determine the presence +or absence of cotton-seed oil fatty acids in mixtures. Equal parts of +the fatty acids, amyl alcohol, and a 1 per cent. solution of sulphur in +carbon bisulphide, are heated in a test-tube placed in a water-bath +until effervescence ceases, then in boiling brine for one hour or longer +when only small quantities are present. The presence of cotton-seed oil +is denoted by a pink coloration. The reaction is rendered much more +rapid, according to Rupp (_Z. Untersuch. Nahr. Genussm._, 1907, 13, 74), +by heating in a stoppered flask. + +Other bodies which it is occasionally necessary to test for or determine +in soap include:-- + +_Carbolic acid._--Fifty grammes of the soap are dissolved in water and +20 c.c. of 10 per cent. caustic potash added. The solution is treated +with an excess of brine, the supernatant liquor separated, and the +precipitate washed with brine, the washings being added to the liquor +withdrawn. This is then evaporated to a small bulk, placed in a Muter's +graduated tube, and acidified with mineral acid. + +The volume of separated phenols is observed and stated in percentage on +the soap taken. + +Or the alkaline layer may be rendered acid and steam distilled; the +distillate is made up to a known volume, and a portion titrated by the +Koppeschaar method with standard bromine water. + +_Glycerine._--Five grammes of soap are dissolved in water, decomposed +with dilute sulphuric acid, and the clear fatty acids filtered and +washed. The filtrate is neutralised with barium carbonate, evaporated +to 50 c.c., and the glycerol estimated by the bichromate method detailed +under Crude Glycerine. + +_Starch_ or _gum_ may be detected by dissolving the soap in alcohol, +filtering, and examining the residue on the filter paper. Starch is +readily recognised by the blue coloration it gives with a solution of +iodine in potassium iodide. + +_Sugars_ are tested for by means of Fehlings' solution, in the liquor +separated from the fatty acids, after first boiling with dilute acid to +invert any cane sugar. + +_Mercury_ will be revealed by a black precipitate produced when +sulphuretted hydrogen is added to the liquor separated from the fatty +acids, and may be estimated by filtering off this precipitate on a tared +Gooch's crucible, which is then dried and weighed. + +_Borax or borates_ are tested for in the residue insoluble in alcohol. +This is dissolved in water, rendered faintly acid with dilute +hydrochloric acid, and a strip of turmeric paper immersed for a few +minutes in the liquid. This is then dried in the water-oven, when if any +boric acid compound is present, a bright reddish-pink stain is produced +on the paper, which is turned blue on moistening with dilute alkali. + +The amount of the boric acid radicle may be determined by incinerating +5-10 grammes of soap, extracting with hot dilute acid, filtering, +neutralising this solution to methyl orange, and boiling to expel carbon +dioxide. After cooling, sufficient pure neutralised glycerine is added +to form one-third of the total volume, and the liquid titrated with N/2 +caustic soda solution, using phenol-phthalein as indicator. Each c.c. of +N/2 NaOH solution corresponds to 0.031 gramme crystallised boric acid, +H_{3}BO_{3} or 0.0477 gramme crystallised borax, +Na_{2}B_{4}O_{7}·10H_{2}O. + + +LYES. + +The amounts of caustic alkali (if any), carbonated alkali, and salt +present are determined in the manner already described under Alkali and +Alkali Salts. The glycerol content is ascertained by taking 2.5 grammes, +adding lead subacetate solution, and filtering without increasing the +bulk more than is absolutely necessary; the solution is concentrated to +about 25 c.c., and the oxidation with bichromate and sulphuric acid +conducted as described in the examination of Crude Glycerine. The +solution, after oxidation, is made up to 250 c.c., and titrated against +standard ferrous ammonium sulphate solution, the formula for the +calculation being:-- + + {0.25 - 2.5} + Per cent. of glycerol = { ---} × 40 + { n } + +where n equals the number of c.c. of oxidised lyes required to oxidise +the ferrous ammonium sulphate solution. + +The estimation of actual glycerol in this is necessarily a matter of +considerable importance, and a very large number of processes, which are +constantly being added to, have been suggested for the purpose. +Hitherto, however, only two methods have been generally adopted, _viz._ +the acetin and the bichromate processes. Unfortunately the results +obtained by these do not invariably agree, the latter, which includes +all oxidisable matter as glycerol, giving sometimes considerably higher +results, and it has been suggested that a determination should be made +by both methods, and the average of the two results considered the true +value. This involves a considerable amount of time and trouble, and it +will generally be found sufficient in a works laboratory to determine +the glycerol by one method only in the ordinary course, reserving the +other process for use as a check in case of dispute or doubt. + +_Acetin Method._--This consists in converting the glycerol into its +ester with acetic acid, the acetic triglyceride, or triacetin being +formed. This is then saponified with a known volume of standard alkali, +the excess of which is titrated with acid, and the percentage of +glycerol calculated from the amount of alkali absorbed. + +From 1 to 1.5 grammes of the glycerine is weighed into a conical flask +of about 150 c.c. capacity, 7 or 8 c.c. of acetic anhydride added, +together with about 3 grammes of anhydrous sodium acetate, and the whole +boiled on a sand-bath under a reflux condenser for one to one and a half +hours, after which it is allowed to cool, 50 c.c. water added, and the +ester dissolved by shaking, and gently warming, the reflux condenser +still being attached as the acetin is very volatile. The solution is +then filtered from a white flocculent precipitate, which contains most +of the impurities, into a larger conical flask, of some 500-600 c.c. +capacity, and after cooling, rendered just neutral to phenol-phthalein +by means of N/2 caustic soda solution, the exact point being reached +when the solution acquires a reddish-yellow tint; 25 c.c. of a strong +caustic soda solution is then added, and the liquid boiled for about +fifteen minutes, the excess of alkali being titrated after cooling, with +N/1 or N/2 hydrochloric acid. A blank experiment is carried out +simultaneously, with another 25 c.c. of the soda solution, and the +difference in the amounts of acid required by the two, furnishes a +measure of the alkali required to saponify the acetin formed, and hence +the amount of glycerol in the crude glycerine may be calculated. + +_Example._--1.4367 grammes crude glycerine, after treatment with acetic +anhydride, and neutralising, was saponified with 25 c.c. of a 10 per +cent. caustic soda solution. + + The blank experiment required 111.05 c.c. N/1 hydrochloric acid. + Flask containing acetin " 75.3 c.c. " " + ----- + 35.75 c.c. " " + +Hence, the acetin formed from the glycerol present in 1.4367 grammes of +the crude glycerine required 35.75 c.c. N/1 caustic alkali for its +saponification, so that the percentage of glycerol may be calculated +from the following formula:-- + + 35.75 × 0.03067 × 100 + Per cent. glycerol = --------------------- = 76.3. + 1.4367 + +_Bichromate Method._--This process was originally devised by Hehner +(_Journ. Soc. Chem. Ind._, 1889, 4-9), but the modification suggested by +Richardson and Jaffe (_ibid._, 1898, 330) is preferred by the authors, +and has been practised by them for several years with perfectly +satisfactory results. + +Twenty-five grammes of the crude glycerine are weighed out in a beaker, +washed into a 250 c.c. stoppered flask, and made up to the graduation +mark with water. Twenty-five c.c. of this solution are then measured +from a burette into a small beaker, a slight excess of basic lead +acetate solution added to precipitate organic matter, the precipitate +allowed to settle, and the supernatant liquid poured through a filter +paper into another 250 c.c. flask. The precipitate is washed by +decantation until the flask is nearly full, then transferred to the +filter, and allowed to drain, a few drops of dilute sulphuric acid being +added to precipitate the slight excess of basic lead acetate solution, +and the contents of the flask made up with water to 250 c.c. This +solution is filtered, 20 c.c. measured from a burette into a conical +flask of about 150 c.c. capacity, 25 c.c. of a standard potassium +bichromate solution containing 74.86 grammes bichromate per litre added, +together with 50 c.c. of 50 per cent. sulphuric acid, and the whole +placed in a boiling water-bath for one hour, after which it is allowed +to cool, diluted with water to 250 c.c., and this solution run in to 20 +c.c. of a 3 per cent. ferrous ammonium sulphate solution until the +latter is completely oxidised, as shown by no blue coloration being +produced when one drop is brought into contact with one drop of a +freshly prepared solution of potassium ferricyanide on a spot-plate. The +ferrous ammonium sulphate solution is previously standardised by +titration with a potassium bichromate solution of one-tenth the above +strength, made by diluting 10 c.c. of the strong solution to 100 c.c. +with water. + +The reaction taking place in the oxidation may be represented by the +equation:-- + + 3C_{3}H_{5}(OH)_{3} + 7K_{2}Cr_{2}O_{7} + 28H_{2}SO_{4} = + 9CO_{2} + 40H_{2}O + 7K_{2}SO_{4} + 7Cr_{2}(SO_{4})_{3}. + +Now the strong potassium bichromate solution above mentioned is of such +a strength that 1 c.c. will oxidise 0.01 gramme glycerine, and 20 c.c. +of the ferrous ammonium sulphate solution should require about 10 c.c. +of the one-tenth strength bichromate in the blank experiment. If it +requires more or less than this, then the amount of ferrous ammonium +sulphate solution which would require exactly 10 c.c. (corresponding to +0.01 gramme glycerine) is calculated, and the oxidised glycerine +solution run into this until oxidation is complete. + +The formula for the calculation of the percentage of glycerol then +becomes:-- + + {0.25 -(250 × 0.01)} + Per cent. of glycerol = { ---------- } × 500, + { n } + +where n equals the number of c.c. of oxidised glycerine solution +required to oxidise the ferrous ammonium sulphate solution. + +Example:-- + +In the blank experiment 20 c.c. ferrous ammonium sulphate solution +required 9.8 c.c. one-tenth strength bichromate solution, so that 20.4 +c.c. ferrous solution would equal 10 c.c. bichromate. + +20.4 c.c. ferrous solution required 27.8 c.c. of oxidised glycerine +solution before it ceased to give a blue coloration with potassium +ferricyanide. + {0.25 - (250 × 0.01)} + Therefore, per cent. of glycerol = { ------------} × 500 + { 27.8 } + + = 80.04 per cent. + +Other methods have been suggested for the preliminary purification, +_e.g._, silver oxide, silver carbonate and lead subacetate, and copper +sulphate and caustic potash, but the lead subacetate alone with care +gives satisfactory results. + +Other determinations include those of specific gravity, alkalinity, +proportion of salts and chloride, and tests for metals, arsenic, sulphur +compounds, sugar, and fatty acids. + +_Specific gravity_ is determined at 15° C., and may be taken in specific +gravity bottle, or with a Westphal balance or hydrometer It usually +ranges from 1.3 to 1.31. + +_Alkalinity_, which is usually sodium carbonate, and may be somewhat +considerable if the soap has been grained with caustic alkali, is +determined after dilution with water by titrating with N/2 acid, using +methyl orange as indicator. + +_Salts._--These may be determined by gently incinerating 5-6 grammes of +the glycerine, extracting the carbonaceous mass with distilled water, +filtering, and evaporating the filtrate on the water bath. The dried +residue represents the salts in the weight taken. + +_Chloride of sodium_ (common salt) may be estimated by dissolving the +total salts in water, adding potassium chromate, and titrating with N/10 +silver nitrate solution. + +_Copper_, _lead_, _iron_, _magnesium_, and _calcium_ may also be tested +for in the salts, by ordinary reactions. + +_Arsenic_ is best tested for by the Gutzeit method. About 5 c.c. is +placed in a test-tube, a few fragments of granulated zinc free from +arsenic, and 10 c.c. dilute hydrochloric acid added, and the mouth of +the tube covered with a small filter paper, moistened three successive +times with an alcoholic solution of mercury bichloride and dried. After +thirty minutes the filter paper is examined, when a yellow stain will be +observed if arsenic is present. + +_Sulphates._--These may be precipitated with barium chloride in acid +solution, in the usual way, dried, ignited, and weighed. + +_Sulphites_ give with barium chloride a precipitate soluble in +hydrochloric acid. If the precipitate is well washed with hot water, and +a few drops of iodine solution together with starch paste added, the +presence of sulphites is proved by the gradual disappearance of the blue +starch-iodine compound first formed. + +_Thiosulphates_ are detected by precipitating any sulphite and sulphate +with barium chloride, filtering, acidifying, and adding a few drops of +potassium permanganate solution, when in the presence of a mere trace of +thiosulphate, the solution becomes cloudy. + +_Sulphides._--Lewkowitsch recommends testing for these by replacing the +mercury bichloride with lead acetate paper in the Gutzeit arsenic test. +Any sulphide causes a blackening of the lead acetate paper. + +_Sugars_ may be tested for both before and after inversion, by boiling +with Fehlings' solution, when no reduction should take place, if pure. + +_Fatty acids_ are detected by the turbidity they produce when the +diluted glycerine is acidified. + + + + +CHAPTER XI. + +STATISTICS OF THE SOAP INDUSTRY. + + +Until the year 1853 the amount of soap produced annually in this country +was readily obtainable from the official returns collected for the +purpose of levying the duty, and the following figures, taken at +intervals of ten years for the half century prior to that date, show the +steady development of the industry during that period:-- + + _______________________________________________________________ +| | | | | | +| Year. | Manufactured. | Consumed. | Exported. | Duty per Ton. | +|_______|_______________|___________|___________|_______________| +| | | | | | +| | Cwts. | Cwts. | Cwts. | £ | +| 1801 | 509,980 | 482,140 | 26,790 | 21 | +| 1811 | 678,570 | 651,780 | 26,790 | 21 | +| 1821 | 875,000 | 839,290 | 35,710 | 28 | +| 1831 | 1,098,210 | 955,360 | 142,850 | 28 | +| 1841 | 1,776,790 | 1,517,860 | 258,930 | 14 | +| 1851 | 1,937,500 | 1,741,070 | 196,430 | 14 | +|_______|_______________|___________|___________|_______________| + +Since the repeal of the soap duty, the revenue from which had reached +about £1,000,000 per annum, no accurate means of gauging the production +exists, but it is estimated that it has nearly quadrupled during the +last fifty-five years, being now some 7,000,000 or 8,000,000 cwt. per +annum. + +The number of soap manufacturers in the United Kingdom is nearly 300, +and the amount of capital invested in the industry is roughly estimated +to approach £20,000,000 sterling. + +Official figures are still available for the amount and value of soap +annually imported and exported to and from the United Kingdom, the +returns for the last eight years being:-- + +_Imports._ +_________________________________________________________________________ +| | | | | +| | Household. | Toilet. | Total.[13] | +| |_____________________|_____________________|_____________________| +| Year. | | | | | | | +| | Quantity. | Value. | Quantity. | Value. | Quantity. | Value | +|_______|___________|_________|___________|_________|___________|_________| +| | | | | | | | +| | Cwts. | £ | Cwts. | £ | Cwts. | £ | +| 1900 | ... | ... | ... | ... | 191,233 | 244,345 | +| 1901 | ... | ... | ... | ... | 302,555 | 315,026 | +| 1902 | ... | ... | ... | ... | 361,851 | 429,300 | +| 1903 | 273,542 | 284,376 | 25,749 | 98,032 | 462,959 | 499,407 | +| 1904 | 254,425 | 268,408 | 17,962 | 81,162 | 383,122 | 438,966 | +| 1905 | 274,238 | 279,044 | 19,631 | 98,507 | 473,067 | 500,430 | +| 1906 | 309,975 | 311,114 | 18,554 | 101,243 | 399,070 | 468,086 | +| 1907 | 228,035 | 263,965 | 18,244 | 99,432 | 504,710 | 545,385 | +|_______|___________|_________|___________|_________|___________|_________| + +Household and toilet soaps were not given separately prior to 1903. + +The imports during the last three years for which complete figures are +obtainable, came from the following sources:-- + +_Household Soap._ + ______________________________________________________________ +| | | | | +| | 1904. | 1905. | 1906. | +|________________________________|_________|_________|_________| +| | | | | +| | £ | £ | £ | +| From Netherlands | 4,315 | 3,620 | 3,368 | +| France | 14,339 | 17,783 | 24,747 | +| Italy | 24,209 | 18,129 | 32,972 | +| United States | 218,740 | 235,612 | 242,294 | +| Other Foreign Countries | 6,785 | 3,873 | 7,448 | +| |_________|_________|_________| +| | | | | +| Total from Foreign Countries | 268,388 | 279,017 | 310,829 | +| Total from British Possessions | 20 | 27 | 285 | +| |_________|_________|_________| +| | | | | +| Total | 268,408 | 279,044 | 311,114 | +|________________________________|_________|_________|_________| + + +_Toilet Soap._ + ______________________________________________________________ +| | | | | +| | 1904. | 1905. | 1906. | +|________________________________|_________|_________|_________| +| | | | | +| | £ | £ | £ | +| From Germany | 3,509 | 3,516 | 3,001 | +| Netherlands | 5,937 | 5,773 | 5,919 | +| Belgium | 1,568 | 1,861 | 3,145 | +| France | 7,120 | 7,633 | 5,794 | +| Italy | 1,176 | 255 | 1,233 | +| United States | 59,863 | 74,516 | 78,382 | +| Other Foreign Countries | 166 | 147 | 196 | +| |_________|_________|_________| +| | | | | +| Total from Foreign Countries | 79,339 | 93,701 | 97,670 | +| Total from British Possessions | 1,823 | 4,411 | 3,225 | +| |_________|_________|_________| +| | | | | +| Total | 81,162 | 98,112 | 100,895 | +|________________________________|_________|_________|_________| + + +_Exports._ + +The exports from the United Kingdom during the past eight years have +been as follows:-- + + _________________________________________________________________________ +| | | | | +| | Household. | Toilet. | Total.[14] | +| |_______________________|____________________|______________________| +|Year.| | | | | | | +| | Quantity. | Value. | Quantity.| Value. | Quantity. | Value. | +|_____|___________|___________|__________|_________|___________|__________| +| | | | | | | | +| | Cwts. | £ | Cwts. | £ | Cwts. | £ | +| 1900| ... | ... | ... | ... | 874,214 | 939,510| +| 1901| ... | ... | ... | ... | 947,485 | 999,524| +| 1902| ... | ... | ... | ... | 1,051,624 | 1,126,657| +| 1903| 998,995 | 900,814 | 38,372 | 217,928 | 1,057,164 | 1,143,661| +| 1904| 1,049,022 | 955,774 | 40,406 | 228,574 | 1,108,174 | 1,208,712| +| 1905| 1,167,976 | 1,013,837 | 43,837 | 248,425 | 1,230,310 | 1,284,727| +| 1906| 1,131,294 | 1,009,653 | 46,364 | 261,186 | 1,210,598 | 1,309,556| +| 1907| 1,114,624 | 1,095,170 | 50,655 | 280,186 | 1,240,805 | 1,459,113| +|_____|___________|___________|__________|_________|___________|__________| + +Household and toilet soaps were not given separately prior to 1903. + +The exports for the last three years for which complete figures are +available, consisted of the following:-- + +_Household Soap._ + ++----------------------------------------+----------+----------+-----------+ +| | 1904. | 1905. | 1906. | ++----------------------------------------+----------+----------+-----------+ +| | £ | £ | £ | +|To Sweden | 3,027 | 2,911 | 3,677 | +| Norway | 4,173 | 3,921 | 6,005 | +| Netherlands | 39,420 | 41,197 | 48,601 | +| Dutch Possessions in the Indian Seas | 8,586 | 10,293 | 7,746 | +| Belgium | 73,996 | 51,583 | 7,729 | +| France | 11,741 | 12,222 | 22,907 | +| Portuguese East Africa | 28,987 | 42,981 | 40,478 | +| Canary Islands | 24,763 | 27,864 | 27,579 | +| Italy | 2,842 | 3,187 | 3,962 | +| Turkey | 6,974 | 7,858 | 5,897 | +| Egypt | 12,110 | 9,467 | 12,035 | +| China (exclusive of Hong-Kong and | | | | +| Macao) | 49,235 | 114,156 | 89,169 | +| United States | 3,885 | 1,975 | 3,924 | +| Columbia | 3,601 | 501 | 1,364 | +| Ecuador | 3,075 | 3,096 | 6,861 | +| Chili | 5,972 | 4,865 | 9,203 | +| Brazil | 35,197 | 28,198 | 31,726 | +| Argentine Republic | 7,802 | 8,954 | 13,084 | +| Other Foreign Countries | 40,058 | 53,914 | 77,687 | +| +----------+----------+-----------+ +|Total to Foreign Countries | 365,444 | 429,143 | 419,634 | +| +---------------------------------+ +|To Channel Islands | 5,301 | 8,328 | 7,968 | +| Gibraltar | 13,272 | 13,868 | 12,661 | +| British West Africa-- | | | | +| Gold Coast | 22,598 | 18,513 | 23,423 | +| Lagos | 7,751 | 8,032 | 9,518 | +| Nigerian Protectorate | 14,942 | 15,299 | 20,951 | +| Cape of Good Hope | 158,517 | 143,750 | 136,388 | +| Natal | 74,848 | 71,874 | 46,771 | +| British India | | | | +| Bombay (including Kurachi) | 59,406 | 68,945 | 77,867 | +| Madras | 6,364 | 6,697 | 10,355 | +| Bengal, Eastern Bengal and Assam. | 26,534 | 23,087 | 22,648 | +| Burmah | 26,389 | 35,727 | 37,103 | +| Straits Settlements and Dependencies | 26,516 | 32,214 | 39,749 | +| Hong-Kong | 14,119 | 15,153 | 15,685 | +| British West India Islands | 74,069 | 58,881 | 67,331 | +| British Guiana | 12,661 | 12,023 | 11,557 | +| Other British Possessions | 47,043 | 52,303 | 50,044 | +| +----------+----------+-----------+ +|Total to British Possessions | 590,330 | 584,694 | 590,019 | +| +----------+----------+-----------+ +| Total | 955,774 |1,013,837 |1,009,653 | +|----------------------------------------+---------+-----------+-----------+ + +_Toilet Soap._ + ________________________________________________________________ +| | | | | +| | 1904. | 1905. | 1906. | +|__________________________________|_________|_________|_________| +| | | | | +| | £ | £ | £ | +| To Germany | 5,051 | 6,322 | 6,620 | +| Belgium | 3,730 | 3,265 | 3,355 | +| France | 7,903 | 8,988 | 9,324 | +| Portuguese East Africa | 2,215 | 3,973 | 4,658 | +| Egypt | 2,302 | 3,350 | 3,525 | +| China (exclusive of | | | | +| Hong-Kong and Macao) | 3,096 | 3,115 | 3,645 | +| Japan (including Formosa) | 3,300 | 4,649 | 3,382 | +| United States | 50,043 | 50,668 | 52,124 | +| Brazil | 1,879 | 2,241 | 2,292 | +| Other Foreign Countries | 22,002 | 26,081 | 29,214 | +| |_________|_________|_________| +| | | | | +| Total to Foreign Countries | 101,521 | 112,652 | 118,139 | +| |_________|_________|_________| +| | | | | +| To Cape of Good Hope | 14,094 | 14,815 | 14,988 | +| Natal | 8,897 | 11,913 | 7,280 | +| British India-- | | | | +| Bombay (including Kurachi) | 24,665 | 24,672 | 28,316 | +| Madras | 4,333 | 5,851 | 6,624 | +| Bengal, Eastern Bengal | | | | +| and Assam | 14,129 | 16,021 | 15,969 | +| Burmah | 3,299 | 3,400 | 4,667 | +| Straits Settlements and | | | | +| Dependencies | 3,590 | 5,092 | 4,798 | +| Ceylon and Dependencies | 12,210 | 11,118 | 12,854 | +| Australia-- | | | | +| Western Australia | 1,549 | 1,394 | 1,137 | +| South Australia, (including | | | | +| Northern Territory) | 895 | 644 | 637 | +| Victoria | 11,989 | 13,614 | 12,774 | +| New South Wales | 3,920 | 4,278 | 4,139 | +| Queensland | 957 | 1,097 | 1,108 | +| Tasmania | 482 | 315 | 547 | +| New Zealand | 5,093 | 4,498 | 5,503 | +| Canada | 6,382 | 6,196 | 8,185 | +| Other British Possessions | 11,069 | 10,855 | 13,521 | +| |_________|_________|_________| +| | | | | +| Total to British Possessions | 127,053 | 135,773 | 143,047 | +| |_________|_________|_________| +| | | | | +| Total | 228,574 | 248,425 | 261,186 | +|__________________________________|_________|_________|_________| + +The following statistics extracted from official consular reports, etc., +show the extent of the soap industry in other parts of the world. + +_United States._--According to the _Oil, Paint and Drug Report_ the +total production of soap in the United States during 1905, exclusive of +soap products to the value of $1,437,118 made in establishments engaged +primarily in the manufacture of other products, reached a value of +$68,274,700, made up in the following manner:-- + ++------------------------------------+--------------+-------------+ +| | Quantity. | Value. | ++------------------------------------+--------------+-------------+ +| | Lbs. | $ | +|Hard soaps | ... | 56,878,486 | +|Tallow soap | 846,753,798 | 32,610,850 | +|Olein soap | 29,363,376 | 1,363,636 | +|Foots soap | 85,000,133 | 3,090,312 | +|Toilet soaps, including medicated, | | | +| shaving, and other special soaps | 130,225,417 | 9,607,276 | +|Powdered soaps, sold as such | 120,624,968 | 4,358,682 | +|All other soaps | 143,390,957 | 6,097,670 | +|Soft soap | 33,613,416 | 667,064 | +|Special soap articles | ... | 554,881 | ++------------------------------------+--------------+-------------+ + +_France_.--This country exported common soap during 1906 to the value of +£556,000, or £8,000 more than in 1905. + +The chief centre of the soap industry is Marseilles, which, with about +fifty soap factories, produces annually some 3,000,000 cwts. + +_Germany_ imported in 1905 soap and perfumery to the value of £3,032, +that exported amounting to £15,364. + +In Saxony there are eighty soap factories. + +_Russia._--There are fifty large soap factories in Russia, the annual +output from which is about 2,250,000 cwt. + +_Roumania._--This country possesses about 230 small and eighteen large +soap and candle factories, most of which produce only common soap, there +being only one firm--in Bucharest--which makes milled soaps. + +_Denmark._--In this country there are some 200 small soap factories. + +_Australia._--According to a Board of Trade report, there were +ninety-eight soap and candle factories in Australia in 1905, employing +1,568 hands, and producing 495,036 cwt. of soap. + +_Queensland._--In 1905 this country contained twenty-one soap and candle +works, in which 142 hands were employed, and having an output valued at +£86,324. + +_Hong-Kong._--There are about twenty-four soap factories on this island. + +_Japan._--A Swiss consular report states that in Japan there are now +some fifty soap works, producing about 15,000,000 tablets monthly. + +_Fiji Islands._--These possess only one soap factory, the output from +which is 9 cwt. daily. + +The following table, compiled from various consular and other official +returns, shows the quantity and value of soap imported into different +countries and places during the years 1905-7:-- + + _______________________________________________________________________________ + | | | + | Household. | Toilet. | Total. + |___________________|____________________|____________________ + Place and Date. | | | | | | + | Quantity.| Value. |Quantity.| Value. |Quantity.| Value. +__________________|__________|________|_________|__________|_________|__________ + | | | | | | +_Europe_-- | | | | | | + Cyprus, 1905 | ... | ... | ... | ... | ... | £9,983 + Iceland, 1906 | ... | ... | ... | ... | ... | £6,423 + Switzerland, | ... | ... | ... | ... |1,702,800| ... + 1906 | | | | | kilos. | ... + Turkey | ... | ... | ... | ... | About | ... + | | | | |1,800,000| ... + | | | | | lb. per | + | | | | | annum | +_Africa_-- | | | | | | + Algeria, 1906 | 13,609 |£228,640| ... | ... | ... | ... + | tons | | | | | + Cape Colony, |15,897,800|£145,000| 427,600 | ... | ... | ... + 1906 | lb. | | lb. | | | + Gold Coast, 1906| ... | ... | ... | ... | ... | £23,987 + Lourenço, | 357,638 | £4,293 | 36,000 | £2,195 | ... | ... + Marques, 1906| lb. | | lb. | | | + Natal, 1906 |4,263,000 | ... | 9,870 | ... | ... | ... + | lb. | | lb. | | | + Orange River | 2,382,000| £23,000|1,748 lb.| ... | ... | ... + Colony, 1906 | lb. | | | | | + Pemba, 1905 | ... | ... | ... | ... | ... | £1,092 + Rhodesia, 1906 | 257,600 | ... |2,909 lb.| ... | ... | ... + | lb. | | | | | + Southern | | | | | | + Nigeria, 1905| ... | ... | ... | ... | ... | £11,990 + Tangier | ... | ... | ... | ... | ... | £4,554 + Transvaal, 1906 | 4,407,000| £81,000| 202,200 | ... | ... | ... + | lb. | | lb. | | | + Tripoli, 1905 | ... | ... | ... | ... | ... | £6,080 + Tunis, 1906 | ... | ... | ... | ... | 1,539 | £23,727 + | | | | | tons | + Zanzibar, 1906 | ... | ... | ... | ... | ... | £6,102 + | | | | | | +_America_-- | | | | | | + Bahia, 1906 | ... | ... | ... | ... | 1,031 | 606,046 + | | | | | tons | milreis + Brazil, 1906 | ... | ... | ... | ... | 1,782 | ... + | | | | | tons | + | | | | |from U.K.| + British Guiana, | | | | | | + 1906-7 | ... | ... | ... | ... | ... | £13,733 + Canada, 1906-7 | ... | ... | ... | ... | ... | $600,999 + Columbia, 1906--| | | | | | + Cartagena | ... | ... | ... | ... | 65,991 | ... + | | | | | tons | + Barranquilla | ... | ... | ... | ... | 814,671 | $14,712 + | | | | | lb. | + Costa Rica, 1906| ... | ... | ... | ... | ... | £1,269 + | | | | | | from U.K. + | | | | | | + Ecuador, 1904 | ... | ... | ... | ... | 759,034 | ... + | | | | | kilos. | + Granada, 1905 | ... | ... | ... | ... | ... | £3,867 + Guatemala, 1906 | ... | £900 | ... | ... | ... | ... + Martinique, 1906| 693,269 | £6,955 | ... | ... | ... | ... + | kilos. | | | | | + Mexico, 1905-6 | ... | £5,982 | ... | ... | ... | ... + San Domingo, | ... | ... | ... | ... | 754,587 | + 1906 | | | | | lb. | ... + St. Vincent, | | | | | | + 1905-6 | ... | ... | ... | ... | ... | £1,375 + Surinam, 1906 | ... | £3,905 | 1,142 | ... | ... | ... + | | | tons | | | + Trinidad, 1906-7| ... | ... | ... | ... | ... | £29,967 + United States, | | | | | | + 1905 | ... |$399,797| ... |$1,071,446| ... |$1,471,243 +__________________|__________|________|_________|__________|_________|____________ + +________________________________________________________________________________ + | | | + | Household. | Toilet. | Total + |__________________|_________________|________________________ + Place and Date. | | | Quan- | | Quan- | + | Quantity.| Value.| tity. | Value. | tity | Value. +__________________|__________|_______|_______|_________|________|_______________ + | | | | | | +_Asia_-- | | | | | | + Ceylon, 1906 | ... | ... | ... | ... | ... | 423,700 rupees + China, 1906 | ... | ... | ... | ... | ... |£216,042 + Hangchow, 1906 | ... | ... | ... | ... | ... | £5,888 + India, 1906-7 | ... | ... | ... | ... | 183,998| £215,210 + | | | | | cwts.| + Kiungchow, 1905 | ... | £575 | ... | ... | ... | ... + Shanghai, 1905 | ... | ... | ... | ... | ... | £93,256 + Smyrna, 1906 | ... | ... | ... | ... |261 tons| ... + | | | | | | +_Australasia_-- | | | | | | + Australia, 1906 | ... | ... |891,117| £65,840 | ... | ... + | | | lb. | | | + Fiji, 1906 | ... | ... | ... | ... | ... | £1,760 + New Zealand, | | | | | | + 1905 | ... | ... | ... | ... | ... | £36,843 + Philippine | | | | | | + Islands, 1905 | ... | ... | ... | ... | ... | £9,137 +__________________|__________|_______|_______|_________|________|________ + + +_Exports._ +________________________________________________________________________________ + | | | + | Household. | Toilet. | Total + |___________________|__________________|_____________________ + Place and Date. | | | Quan- | | Quan- | + | Quantity.| Value. | tity. | Value. | tity. | Value +___________________|__________|________|_______|__________|_______|_____________ + | | | | | | +_Europe_-- | | | | | | + Candia, Crete, | ... | ... | ... | ... | 2,200 | £34,000 + 1906 | | | | | tons. | + Greece | ... | ... | ... | ... | ... | About + | | | | | | 500,000 Fr. + | | | | | | per annum. + Italy, 1907 | 3,992,800| £95,840| ... | ... | ... | ... + | kilos. | | | | | + Leghorn, 1906 | ... | ... | ... | ... | 1,521 | £37,065 + | | | | | tons. | + Spain, 1905 | 4,750,996| £98,840| ... | ... | ... | ... + | kilos. | | | | | + Switzerland, 1906| ... | ... | ... | ... | 77,300| ... + | | | | | kilos.| +_Africa_-- | | | | | | + Cape Colony, 1906| 200 lb. | ... | ... | ... | ... | ... + Natal, 1906 |75,225 lb.| ... | ... | ... | ... | ... + Seychelles, 1906 | ... | ... | ... | ... |419,329| 129,590 + | | | | | kilos.| Rs. +_America_-- | | | | | | + New Orleans, | ... | ... | ... | ... | ... | £55,534 + 1906 | | | | | | + Perambuco, 1906 | ... | ... | ... | ... | 3,582 |1,087,797,150 + | | | | | tons.| rei + United States, |44,110,949| ... | ... |$1,042,185| ... | ... + 1905 | lb. | | | | | + | | | | | | +_Asia_-- | | | | | | + Japan, 1906 | ... | ... | ... | ... | ... | £83,877 + Smyrna, 1906 | ... | ... | ... | ... | 322 | ... + | | | | | tons. | +___________________|__________|________|_______|__________|_______|_____________ + +FOOTNOTES: + +[13] Including soap powder and soap stock. + +[14] Including soap powder and soap stock. + + + + +APPENDIX A. + +COMPARISON OF DEGREES, TWADDELL AND BAUMÉ, WITH ACTUAL DENSITIES. + + + _______________________________________________ +| | | | | | | +| Tw. | B. | Density. | Tw. | B. | Density. | +|_____|______|__________|_____|______|__________| +| | | | | | | +| 0 | 0 | 1.000 | 44 | 26.0 | 1.220 | +| 1 | 0.7 | 1.005 | 45 | 26.4 | 1.225 | +| 2 | 1.4 | 1.010 | 46 | 26.9 | 1.230 | +| 3 | 2.1 | 1.015 | 47 | 27.4 | 1.235 | +| 4 | 2.7 | 1.020 | 48 | 27.9 | 1.240 | +| 5 | 3.4 | 1.025 | 49 | 28.4 | 1.245 | +| 6 | 4.1 | 1.030 | 50 | 28.8 | 1.250 | +| 7 | 4.7 | 1.035 | 51 | 29.3 | 1.255 | +| 8 | 5.4 | 1.040 | 52 | 29.7 | 1.260 | +| 9 | 6.0 | 1.045 | 53 | 30.2 | 1.265 | +| 10 | 6.7 | 1.050 | 54 | 30.6 | 1.270 | +| 11 | 7.4 | 1.055 | 55 | 31.1 | 1.275 | +| 12 | 8.0 | 1.060 | 56 | 31.5 | 1.280 | +| 13 | 8.7 | 1.065 | 57 | 32.0 | 1.285 | +| 14 | 9.4 | 1.070 | 58 | 32.4 | 1.290 | +| 15 | 10.0 | 1.075 | 59 | 32.8 | 1.295 | +| 16 | 10.6 | 1.080 | 60 | 33.3 | 1.300 | +| 17 | 11.2 | 1.085 | 61 | 33.7 | 1.305 | +| 18 | 11.9 | 1.090 | 62 | 34.2 | 1.310 | +| 19 | 12.4 | 1.095 | 63 | 34.6 | 1.315 | +| 20 | 13.0 | 1.100 | 64 | 35.0 | 1.320 | +| 21 | 13.6 | 1.105 | 65 | 35.4 | 1.325 | +| 22 | 14.2 | 1.110 | 66 | 35.8 | 1.330 | +| 23 | 14.9 | 1.115 | 67 | 36.2 | 1.335 | +| 24 | 15.4 | 1.120 | 68 | 36.6 | 1.340 | +| 25 | 16.0 | 1.125 | 69 | 37.0 | 1.345 | +| 26 | 16.5 | 1.130 | 70 | 37.4 | 1.350 | +| 27 | 17.1 | 1.135 | 71 | 37.8 | 1.355 | +| 28 | 17.7 | 1.140 | 72 | 38.2 | 1.360 | +| 29 | 18.3 | 1.145 | 73 | 38.6 | 1.365 | +| 30 | 18.8 | 1.150 | 74 | 39.0 | 1.370 | +| 31 | 19.3 | 1.155 | 75 | 39.4 | 1.375 | +| 32 | 19.8 | 1.160 | 76 | 39.8 | 1.380 | +| 33 | 20.3 | 1.165 | 77 | 40.1 | 1.385 | +| 34 | 20.9 | 1.170 | 78 | 40.5 | 1.390 | +| 35 | 21.4 | 1.175 | 79 | 40.8 | 1.395 | +| 36 | 22.0 | 1.180 | 80 | 41.2 | 1.400 | +| 37 | 22.5 | 1.185 | 81 | 41.6 | 1.405 | +| 38 | 23.0 | 1.190 | 82 | 42.0 | 1.410 | +| 39 | 23.5 | 1.195 | 83 | 42.3 | 1.415 | +| 40 | 24.0 | 1.200 | 84 | 42.7 | 1.420 | +| 41 | 24.5 | 1.205 | 85 | 43.1 | 1.425 | +| 42 | 25.0 | 1.210 | 86 | 43.4 | 1.430 | +| 43 | 25.5 | 1.215 | 87 | 48.8 | 1.435 | +|_____|______|__________|_____|______|__________| + + _______________________________________________ +| | | | | | | +| Tw. | B. | Density. | Tw. | B. | Density. | +|_____|______|__________|_____|______|__________| +| | | | | | | +| 88 | 44.1 | 1.440 | 131 | 57.1 | 1.655 | +| 89 | 44.4 | 1.445 | 132 | 57.4 | 1.660 | +| 90 | 44.8 | 1.450 | 133 | 57.7 | 1.665 | +| 91 | 45.1 | 1.455 | 134 | 57.9 | 1.670 | +| 92 | 45.4 | 1.460 | 135 | 58.2 | 1.675 | +| 93 | 45.8 | 1.465 | 136 | 58.4 | 1.680 | +| 94 | 46.1 | 1.470 | 137 | 58.7 | 1.685 | +| 95 | 46.4 | 1.475 | 138 | 58.9 | 1.690 | +| 96 | 46.8 | 1.480 | 139 | 59.2 | 1.695 | +| 97 | 47.1 | 1.485 | 140 | 59.5 | 1.700 | +| 98 | 47.4 | 1.490 | 141 | 59.7 | 1.705 | +| 99 | 47.8 | 1.495 | 142 | 60.0 | 1.710 | +| 100 | 48.1 | 1.500 | 143 | 60.2 | 1.715 | +| 101 | 48.4 | 1.505 | 144 | 60.4 | 1.720 | +| 102 | 48.7 | 1.510 | 145 | 60.6 | 1.725 | +| 103 | 49.0 | 1.515 | 146 | 60.9 | 1.730 | +| 104 | 49.4 | 1.520 | 147 | 61.1 | 1.735 | +| 105 | 49.7 | 1.525 | 148 | 61.4 | 1.740 | +| 106 | 50.0 | 1.530 | 149 | 61.6 | 1.745 | +| 107 | 50.3 | 1.535 | 150 | 61.8 | 1.750 | +| 108 | 50.6 | 1.540 | 151 | 62.1 | 1.755 | +| 109 | 50.9 | 1.545 | 152 | 62.3 | 1.760 | +| 110 | 51.2 | 1.550 | 153 | 62.5 | 1.765 | +| 111 | 51.5 | 1.555 | 154 | 62.8 | 1.770 | +| 112 | 51.8 | 1.560 | 155 | 63.0 | 1.775 | +| 113 | 52.1 | 1.565 | 156 | 63.2 | 1.780 | +| 114 | 52.4 | 1.570 | 157 | 63.5 | 1.785 | +| 115 | 52.7 | 1.575 | 158 | 63.7 | 1.790 | +| 116 | 53.0 | 1.580 | 159 | 64.0 | 1.795 | +| 117 | 53.3 | 1.585 | 160 | 64.2 | 1.800 | +| 118 | 53.6 | 1.590 | 161 | 64.4 | 1.805 | +| 119 | 53.9 | 1.595 | 162 | 64.6 | 1.810 | +| 120 | 54.1 | 1.600 | 163 | 64.8 | 1.815 | +| 121 | 54.4 | 1.605 | 164 | 65.0 | 1.820 | +| 122 | 54.7 | 1.610 | 165 | 65.2 | 1.825 | +| 123 | 55.0 | 1.615 | 166 | 65.5 | 1.830 | +| 124 | 55.2 | 1.620 | 167 | 65.7 | 1.835 | +| 125 | 55.5 | 1.625 | 168 | 65.9 | 1.840 | +| 126 | 55.8 | 1.630 | 169 | 66.1 | 1.845 | +| 127 | 56.0 | 1.635 | 170 | 66.3 | 1.850 | +| 128 | 56.3 | 1.640 | 171 | 66.5 | 1.855 | +| 129 | 56.6 | 1.645 | 172 | 66.7 | 1.860 | +| 130 | 56.9 | 1.650 | 173 | 67.0 | 1.865 | +|_____|______|__________|_____|______|__________| + +(From _The Oil and Colour Trades Journal_ Diary.) + + + + +APPENDIX B. + +COMPARISON OF DIFFERENT THERMOMETRIC SCALES. + + + _______________________________________________________________ +| | | | | | | | | +| Cent. | Fahr. | Cent. | Fahr. | Cent. | Fahr. | Cent. | Fahr. | +|_______|_______|_______|_______|_______|_______|_______|_______| +| | | | | | | | | +| -40 | -40 | 2 | 35.6 | 44 | 111.2 | 86 | 186.8 | +| 39 | 38.2 | 3 | 87.4 | 45 | 113 | 87 | 188.6 | +| 38 | 36.4 | 4 | 39.2 | 46 | 114.8 | 88 | 190.4 | +| 37 | 34.6 | 5 | 41 | 47 | 116.6 | 89 | 192.2 | +| 36 | 32.8 | 6 | 42.8 | 48 | 118.4 | 90 | 194 | +| 35 | 31 | 7 | 44.6 | 49 | 120.2 | 91 | 195.8 | +| 34 | 29.2 | 8 | 46.4 | 50 | 122 | 92 | 197.6 | +| 33 | 27.4 | 9 | 48.2 | 51 | 123.8 | 93 | 199.4 | +| 32 | 25.6 | 10 | 50 | 52 | 125.6 | 94 | 201.2 | +| 31 | 23.8 | 11 | 51.8 | 53 | 127.4 | 95 | 203 | +| 30 | 22 | 12 | 58.6 | 54 | 129.2 | 96 | 204.8 | +| 29 | 20.2 | 13 | 55.4 | 55 | 131 | 97 | 206.6 | +| 28 | 18.4 | 14 | 57.2 | 56 | 132.8 | 98 | 208.4 | +| 27 | 16.6 | 15 | 59 | 57 | 134.6 | 99 | 210.2 | +| 26 | 14.8 | 16 | 60.8 | 58 | 136.4 | 100 | 212 | +| 25 | 13 | 17 | 62.6 | 59 | 138.2 | 101 | 213.8 | +| 24 | 11.2 | 18 | 64.4 | 60 | 140 | 102 | 215.6 | +| 23 | 9.4 | 19 | 66.2 | 61 | 141.8 | +103 |+217.4 | +| 22 | 7.6 | 20 | 68 | 62 | 143.6 | 104 | 219.2 | +| 21 | 5.8 | 21 | 69.8 | 63 | 145.4 | 105 | 221 | +| 20 | 4 | 22 | 71.6 | 64 | 147.2 | 106 | 222.8 | +| 19 | 2.2 | 23 | 73.4 | 65 | 149 | 107 | 224.6 | +| 18 | 0.4 | 24 | 75.2 | 66 | 150.8 | 108 | 226.4 | +| 17 | +1.4 | 25 | 77 | 67 | 152.6 | 109 | 228.2 | +| 16 | 3.2 | 26 | 78.8 | +68 |+154.4 | +110 |+230 | +| 15 | 5 | 27 | 80.6 | 69 | 156.2 | 111 | 231.8 | +| 14 | 6.8 | 28 | 82.4 | 70 | 158 | 112 | 283.6 | +| 13 | 8.6 | 29 | 84.2 | 71 | 159.8 | 113 | 235.4 | +| 12 | 10.4 | 30 | 86 | 72 | 161.6 | 114 | 237.2 | +| 11 | 12.2 | 31 | 87.8 | 73 | 163.4 | 115 | 239 | +| 10 | 14 | +32 | +89.6 | 74 | 165.2 | +116 |+240.8 | +| 9 | 15.8 | 33 | 91.4 | 75 | 167 | 117 | 242.6 | +| 8 | 17.6 | 34 | 93.2 | 76 | 168.8 | 118 | 244.4 | +| 7 | 19.4 | 35 | 95 | 77 | 170.6 | 119 | 246.2 | +| 6 | 21.2 | 36 | 96.8 | 78 | 172.4 | 120 | 248 | +| 5 | 23 | 37 | 98.6 | 79 | 174.2 | 121 | 249.8 | +| -4 | 24.8 | 49 | 100.4 | 80 | 176 | +122 |+251.6 | +| 3 | 26.6 | 39 | 102.2 | 81 | 177.8 | 123 | 253.4 | +| 2 | 28.4 | 40 | 104 | 82 | 179.6 | 124 | 255.2 | +| 1 | 30.2 | 41 | 105.8 | 83 | 181.4 | 125 | 257 | +| 0 | 32 | 42 | 107.6 | 84 | 183.2 | 126 | 258.8 | +| +1 | 33.8 | 43 | 109.4 | 85 | 185 | 127 | 260.6 | +|_______|_______|_______|_______|_______|_______|_______|_______| + +(From _Soaps_, by G. H. Hurst, published by Scott, Greenwood & Son.) + + + + +APPENDIX C. + +TABLE OF THE SPECIFIC GRAVITIES OF SOLUTIONS OF CAUSTIC SODA. + + + _________________________________________________________________________ +| | | | | +| | | Per cent. by | Lb. of actual NaOH contained | +| | | weight of | in 1 gallon of lye made from | +| | | | commercial caustic of | +| Degrees | Specific |___________________|______________________________| +| Twaddell. | gravity. | | | | | | +| | | Na_{2}O. | NaOH. | 77 per | 74 per | 70 per | +| | | | | cent. | cent. | cent. | +|___________|__________|__________|________|_________|_________|__________| +| | | | | | | | +| 1 | 1.005 | 0.368 | 0.474 | 0.048 | 0.046 | 0.043 | +| 2 | 1.010 | 0.742 | 0.957 | 0.097 | 0.092 | 0.087 | +| 3 | 1.015 | 1.114 | 1.436 | 0.146 | 0.131 | 0.129 | +| 4 | 1.020 | 1.480 | 1.909 | 0.194 | 0.185 | 0.180 | +| 5 | 1.025 | 1.834 | 2.365 | 0.243 | 0.231 | 0.219 | +| 6 | 1.030 | 2.194 | 2.830 | 0.291 | 0.278 | 0.262 | +| 7 | 1.035 | 2.521 | 3.252 | 0.335 | 0.320 | 0.303 | +| 8 | 1.040 | 2.964 | 3.746 | 0.389 | 0.371 | 0.350 | +| 9 | 1.045 | 3.244 | 4.184 | 0.438 | 0.417 | 0.393 | +| 10 | 1.050 | 3.590 | 4.631 | 0.486 | 0.461 | 0.438 | +| 11 | 1.055 | 3.943 | 5.086 | 0.536 | 0.510 | 0.483 | +| 12 | 1.060 | 4.292 | 5.536 | 0.586 | 0.558 | 0.528 | +| 13 | 1.065 | 4.638 | 5.982 | 0.636 | 0.607 | 0.573 | +| 14 | 1.070 | 4.972 | 6.413 | 0.680 | 0.653 | 0.617 | +| 15 | 1.075 | 5.311 | 6.911 | 0.742 | 0.707 | 0.668 | +| 16 | 1.080 | 5.648 | 7.285 | 0.786 | 0.749 | 0.709 | +| 17 | 1.085 | 5.981 | 7.715 | 0.836 | 0.798 | 0.755 | +| 18 | 1.090 | 6.311 | 8.140 | 0.886 | 0.845 | 0.800 | +| 19 | 1.095 | 6.639 | 8.564 | 0.937 | 0.894 | 0.846 | +| 20 | 1.100 | 6.954 | 8.970 | 0.986 | 0.941 | 0.890 | +| 21 | 1.105 | 7.276 | 9.386 | 1.037 | 0.989 | 0.938 | +| 22 | 1.110 | 7.594 | 9.796 | 1.087 | 1.037 | 0.981 | +| 23 | 1.115 | 7.910 | 10.203 | 1.137 | 1.123 | 1.026 | +| 24 | 1.120 | 8.223 | 10.607 | 1.187 | 1.175 | 1.071 | +| 25 | 1.125 | 8.583 | 11.107 | 1.238 | 1.181 | 1.117 | +| 26 | 1.130 | 8.893 | 11.471 | 1.296 | 1.237 | 1.170 | +| 27 | 1.135 | 9.251 | 11.933 | 1.354 | 1.292 | 1.122 | +| 28 | 1.140 | 9.614 | 12.401 | 1.413 | 1.350 | 1.277 | +| 29 | 1.145 | 9.965 | 12.844 | 1.470 | 1.413 | 1.337 | +| 30 | 1.150 | 10.313 | 13.303 | 1.529 | 1.460 | 1.381 | +| 31 | 1.155 | 10.666 | 13.859 | 1.600 | 1.528 | 1.445 | +| 32 | 1.160 | 11.008 | 14.190 | 1.646 | 1.541 | 1.456 | +| 33 | 1.165 | 11.347 | 14.637 | 1.705 | 1.627 | 1.539 | +| 34 | 1.170 | 11.691 | 15.081 | 1.764 | 1.684 | 1.593 | +| 35 | 1.175 | 12.025 | 15.512 | 1.822 | 1.739 | 1.645 | +| 36 | 1.180 | 12.356 | 16.139 | 1.904 | 1.817 | 1.719 | +| 37 | 1.185 | 12.692 | 16.372 | 1.942 | 1.853 | 1.753 | +| 38 | 1.190 | 13.016 | 16.794 | 1.998 | 1.887 | 1.804 | +| 39 | 1.195 | 13.339 | 17.203 | 2.055 | 1.962 | 1.856 | +| 40 | 1.200 | 13.660 | 17.629 | 2.122 | 2.026 | 1.916 | +| 41 | 1.205 | 14.058 | 18.133 | 2.185 | 2.085 | 1.973 | +| 42 | 1.210 | 14.438 | 18.618 | 2.252 | 2.147 | 2.033 | +| 43 | 1.215 | 14.823 | 19.121 | 2.323 | 2.221 | 2.097 | +| 44 | 1.220 | 15.124 | 19.613 | 2.392 | 2.280 | 2.161 | +| 45 | 1.225 | 15.502 | 19.997 | 2.444 | 2.338 | 2.206 | +| 46 | 1.230 | 15.959 | 20.586 | 2.562 | 2.417 | 2.285 | +| 47 | 1.235 | 16.299 | 20.996 | 2.593 | 2.475 | 2.341 | +| 48 | 1.240 | 16.692 | 21.532 | 2.669 | 2.548 | 2.410 | +|___________|__________|__________|________|_________|_________|__________| + + _________________________________________________________________________ +| | | | | +| | | Per cent. by | Lb. of actual NaOH contained | +| | | weight of | in 1 gallon of lye made from | +| | | | commercial caustic of | +| Degrees | Specific |___________________|______________________________| +| Twaddell. | gravity. | | | | | | +| | | Na_{2}O. | NaOH. | 77 per | 74 per | 70 per | +| | | | | cent. | cent. | cent. | +|___________|__________|__________|________|_________|_________|__________| +| | | | | | | | +| 49 | 1.245 | 17.060 | 22.008 | 2.739 | 2.615 | 2.474 | +| 50 | 1.250 | 17.424 | 22.476 | 2.809 | 2.681 | 2.536 | +| 51 | 1.255 | 17.800 | 22.962 | 2.881 | 2.750 | 2.602 | +| 52 | 1.260 | 18.166 | 23.433 | 2.952 | 2.818 | 2.666 | +| 53 | 1.265 | 18.529 | 23.901 | 3.020 | 2.886 | 2.730 | +| 54 | 1.270 | 18.897 | 24.376 | 3.095 | 2.955 | 2.795 | +| 55 | 1.275 | 19.255 | 24.858 | 3.171 | 3.027 | 2.863 | +| 56 | 1.280 | 19.609 | 25.295 | 3.237 | 3.090 | 2.932 | +| 57 | 1.285 | 19.961 | 25.750 | 3.308 | 3.158 | 2.988 | +| 58 | 1.290 | 20.318 | 26.210 | 3.381 | 3.227 | 3.053 | +| 59 | 1.295 | 20.655 | 26.658 | 3.452 | 3.364 | 3.117 | +| 60 | 1.300 | 21.156 | 27.110 | 3.524 | 3.394 | 3.182 | +| 61 | 1.305 | 21.405 | 27.611 | 3.603 | 3.439 | 3.253 | +| 62 | 1.310 | 21.785 | 28.105 | 3.682 | 3.514 | 3.224 | +| 63 | 1.315 | 22.168 | 28.595 | 3.760 | 3.593 | 3.395 | +| 64 | 1.320 | 22.556 | 29.161 | 3.849 | 3.674 | 3.475 | +| 65 | 1.325 | 22.926 | 29.574 | 3.919 | 3.742 | 3.539 | +| 66 | 1.330 | 23.310 | 30.058 | 3.997 | 3.816 | 3.610 | +| 67 | 1.335 | 23.670 | 30.535 | 4.072 | 3.891 | 3.681 | +| 68 | 1.340 | 24.046 | 31.018 | 4.156 | 3.967 | 3.754 | +| 69 | 1.345 | 24.410 | 31.490 | 4.232 | 4.042 | 3.824 | +| 70 | 1.350 | 24.765 | 31.948 | 4.312 | 4.116 | 3.894 | +| 71 | 1.355 | 25.152 | 32.446 | 4.396 | 4.196 | 3.970 | +| 72 | 1.360 | 25.526 | 32.930 | 4.478 | 4.274 | 4.043 | +| 73 | 1.365 | 25.901 | 33.415 | 4.561 | 4.354 | 4.109 | +| 74 | 1.370 | 26.285 | 33.905 | 4.645 | 4.434 | 4.194 | +| 75 | 1.375 | 26.650 | 34.382 | 4.728 | 4.513 | 4.269 | +| 76 | 1.380 | 27.021 | 34.855 | 4.810 | 4.592 | 4.344 | +| 77 | 1.385 | 27.385 | 35.328 | 4.893 | 4.670 | 4.418 | +| 78 | 1.390 | 27.745 | 35.795 | 4.975 | 4.794 | 4.493 | +| 79 | 1.395 | 28.110 | 36.258 | 5.058 | 4.828 | 4.567 | +| 80 | 1.400 | 28.465 | 36.720 | 5.141 | 4.907 | 4.642 | +| 81 | 1.405 | 28.836 | 37.203 | 5.227 | 4.989 | 4.720 | +| 82 | 1.410 | 29.203 | 37.674 | 5.312 | 5.071 | 4.797 | +| 83 | 1.415 | 29.570 | 38.146 | 5.397 | 5.135 | 4.873 | +| 84 | 1.420 | 29.930 | 38.610 | 5.482 | 5.233 | 4.950 | +| 85 | 1.425 | 30.285 | 39.071 | 5.567 | 5.314 | 5.027 | +| 86 | 1.430 | 30.645 | 39.530 | 5.653 | 5.396 | 5.104 | +| 87 | 1.435 | 30.995 | 39.986 | 5.738 | 5.467 | 5.181 | +| 88 | 1.440 | 31.349 | 40.435 | 5.823 | 5.558 | 5.258 | +| 89 | 1.445 | 31.700 | 40.882 | 5.908 | 5.640 | 5.335 | +| 90 | 1.450 | 32.043 | 41.335 | 5.923 | 5.721 | 5.412 | +| 91 | 1.455 | 32.460 | 41.875 | 6.093 | 5.816 | 5.502 | +| 92 | 1.460 | 32.870 | 42.400 | 6.191 | 5.909 | 5.608 | +| 93 | 1.465 | 33.283 | 42.935 | 6.290 | 6.004 | 5.679 | +| 94 | 1.470 | 33.695 | 43.467 | 6.389 | 6.009 | 5.769 | +| 95 | 1.475 | 34.092 | 43.980 | 6.487 | 6.193 | 5.856 | +| 96 | 1.480 | 34.500 | 44.505 | 6.586 | 6.287 | 5.948 | +| 97 | 1.485 | 34.899 | 45.013 | 6.685 | 6.381 | 6.035 | +| 98 | 1.490 | 35.245 | 45.530 | 6.784 | 6.476 | 6.126 | +| 99 | 1.495 | 35.691 | 46.041 | 6.884 | 6.571 | 6.216 | +| 100 | 1.500 | 36.081 | 46.545 | 6.982 | 6.665 | 6.303 | +|___________|__________|__________|________|_________|_________|__________| + +(From _Soaps_, by G. H. Hurst, published by Scott, Greenwood & Son.) + + + + +APPENDIX D. + +TABLE OF STRENGTH OF CAUSTIC POTASH SOLUTIONS AT 60° F. + + + _______________________________________________ +| | | | | +| Specific | Degrees | Per cent. | Lb. of KOH | +| gravity. | Twaddell. | KOH. | per gal. | +|__________|___________|___________|____________| +| | | | | +| 1.060 | 12 | 5.59 | 0.59 | +| 1.110 | 22 | 11.31 | 1.25 | +| 1.150 | 30 | 15.48 | 1.77 | +| 1.190 | 38 | 19.29 | 2.21 | +| 1.230 | 46 | 23.22 | 2.84 | +| 1.280 | 56 | 27.87 | 3.56 | +| 1.330 | 66 | 31.32 | 4.16 | +| 1.360 | 72 | 35.01 | 4.76 | +| 1.390 | 78 | 38.59 | 5.36 | +| 1.420 | 84 | 40.97 | 5.81 | +| 1.440 | 88 | 43.83 | 6.31 | +| 1.470 | 94 | 47.16 | 6.93 | +| 1.520 | 104 | 51.09 | 7.76 | +| 1.600 | 112 | 55.62 | 8.89 | +| 1.680 | 136 | 60.98 | 10.24 | +| 1.780 | 156 | 67.65 | 12.04 | +| 1.880 | 176 | 75.74 | 14.23 | +| 2.000 | 200 | 86.22 | 17.24 | +|__________|___________|___________|____________| + +(From _Soaps_, by G. H. Hurst, published by Scott, Greenwood & Son.) + + +THE END. + + + + +INDEX. + + +A. + +Acetic Acid, 10 + +Acid, Acetic, 10 + +---- Arachidic, 10 + +---- Behenic, 10 + +---- Butyric, 10 + +---- Capric, 10 + +---- Caproic, 10 + +---- Caprylic, 10 + +---- Carnaubic, 10 + +---- Cerotic, 10 + +---- Daturic, 10 + +---- Doeglic, 11 + +---- Elæomargaric, 12 + +---- Elæostearic, 12 + +---- Erucic, 11 + +---- Ficocerylic, 10 + +---- Hyænic, 10 + +---- Hypogæic, 11 + +---- Isolinolenic, 12 + +---- Isovaleric, 10 + +---- Jecoric, 12 + +---- Lauric, 10 + +---- Lignoceric, 10 + +---- Linolenic, 12 + +---- Linolic, 12 + +---- Margaric, 10 + +---- Medullic, 10 + +---- Melissic, 10 + +---- Moringic, 11 + +---- Myristic, 10 + +---- Oleic, 11 + +---- Palmitic, 10 + +---- Physetoleic, 11 + +---- Pisangcerylic, 10 + +---- Psyllostearylic, 10 + +---- Rapic, 11 + +---- Ricinoleic, 13 + +---- Saponification, 19-21 + +---- Stearic, 10 + +---- Tariric, 12 + +---- Telfairic, 12 + +---- Theobromic, 10 + +---- Tiglic, 11 + +---- value, 118, 128 + +Acids, Classification of fatty, 10 + +---- Fatty, 9-13 + +---- ---- Combination with Alkali, 45, 46 + +Acids, Fatty, Preparation by acid process, 19-21 + +---- ---- ---- by ferment process, 16 + +---- ---- ---- by Twitchell's process, 20 + +---- Saturated fatty, 11 + +---- Unsaturated fatty, 11 + +Albumen in soap, 90 + +Alcohols, Estimation of, 128 + +Aldehydes, Estimation of, 129 + +Alkali, Caustic and carbonated, 38, 39, 123-126 + +Alkali in soap, Determination of, 131, 132 + +Amyl salicylate, 107 + +Andiroba oil, 32 + +Animal charcoal, 115 + +---- fats, Treatment of, 43 + +Anise (star) oil, 96 + +Anisic aldehyde, 108 + +Arachidic acid, 10 + +Arachis oil, 28 + +Artificial perfumes, 107-110 + +Ash, Soda, 39, 124, 125 + +Aspic oil, 96 + +Aqueous saponification, 14 + +Aubépine, 108 + + +B. + +Bacteria, Decomposition of fats by, 18 + +Baobab-seed oil, 36 + +Bar soap, 54, 55 + +Barring soap, 68 + +Bay oil, 97 + +Behenic acid, 10 + +Benzyl acetate, 108 + +Bergamot oil, 97 + +---- ---- (artificial), 109 + +Biniodide soaps, 87 + +Birch-tar soap, 88 + +Bitter almond oil, 97 + +Bleaching palm oil, 41 + +---- rosin, 43 + +Boiling-on-strength, 51 + +Bois de Rose Femelle oil, 99 + +Bone-fat, 30 + +---- ---- treatment of, 43 + +Borax in soap, 88 + +Boric acid in soap, 88 + +Boric acid in soap, Determination of, 135 + +Borneo tallow, 32 + +Brine, 39 + +Bromine absorption of oils and fats, 122 + +Brown Windsor soap, 78, 98 + +Butter goa, 33 + +---- kokum, 33 + +---- shea, 31 + +Butyric acid, 10 + +Butyrin, 8 + + +C. + +Calico-printer's soap, 93 + +Cananga oil, 98 + +Candle-nut oil, 33 + +Capric acid, 10 + +Caprin, 8 + +Caproic acid, 10 + +Caproin, 8 + +Caprylic acid, 10 + +Caprylin, 8 + +Carapa oil, 32 + +Caraway oil, 98 + +Carbolic acid in soap, Determination of, 134 + +Carbolic soap, 88 + +Carbonate potash, 39, 125, 126 + +---- soda, 39, 124, 125 + +Carnaubic acid, 10 + +Cassia oil, 98 + +Castor oil, 30 + +Caustic potash, 39, 123 + +---- soda, 39, 123 + +Cayenne linaloe oil, 99 + +Cedarwood oil, 98 + +Cerotic acid, 10 + +Charcoal, Animal, 115 + +Chinese vegetable tallow, 31 + +Cholesterol in unsaponified matter, 120 + +Cinnamon oil, 98 + +Citral, 108 + +Citronella oil, 99 + +Citronellal, 108 + +Cleansing soap, 60, 61 + +Close-piling soap, 71 + +Clove oil, 99 + +Coal tar soaps, 88 + +Cocoa-nut oil, 25, 26 + +Cohune-nut oil, 34 + +Cold process soap-making, 46, 47 + +Colouring soap, 66, 80, 82 + +Compressing soap, 83, 85 + +Concrete orris oil, 100 + +Constitution of oils and fats, 6, 7 + +Conversion of oleic acid into solid acids, 11, 12 + +Cooling soap, 74, 76 + +Coprah oil, 25, 26 + +Cotton-seed oil, 27, 42 + +---- ---- Refining, 42 + +---- soapstock, 40 + +---- stearine, 28 + +Coumarin, 108 + +Crude glycerine, 113, 136-139 + +Crutching soap, 63 + +Curcas oil, 33 + +Curd mottled soap, 52, 53 + +Curd soaps, 52 + +Cutting and stamping toilet soap, 85 + + +D. + +Daturic acid, 10 + +Decolorisation, Glycerine, 115 + +Decomposition of fats by bacteria, 18 + +Detergent action of soap, 4, 5 + +Diglycerides, 7 + +Dika fat, 36 + +Disinfectant soaps, 66 + +Distearine, 7 + +Distillation, glycerine, 114 + +Distilled glycerine, 114 + +Doeglic acid, 11 + +Double distilled glycerine, 115 + +Dregs in fats and oils, Determination of, 120, 121 + +Drying soap, 71, 78-80 + +Dynamite glycerine, 115 + + +E. + +Elaidin reaction, 12 + +Electrical production of soap, 59 + +Elæomargaric acid, 12 + +Elæostearic acid, 12 + +Enzymes, Action of, 15-18 + +Erucic acid, 11 + +Essential oils, 96-107 + +---- ---- Examination of, 127-130 + +Ester value, 119, 128 + +Ether soap, 90 + +Eucalyptus oil, 100 + +Evaporation to crude glycerine, 112, 113 + + +F. + +Fat, Bone, 30 + +---- Dika, 36 + +---- Maripa, 34 + +---- Marrow, 30 + +---- Niam, 34 + +---- Tangkallah, 37 + +---- Treatment of bone, 43 + +Fats, Decomposition by bacteria of, 18 + +---- Treatment of animal, 43 + +---- Waste, 30 + +Fats and oils, Determination of acid value of, 118 + +---- ---- ---- of bromine absorption of, 122 + +---- ---- ---- of dregs, etc., in, 120, 121 + +---- ---- ---- of free acidity of, 117 + +---- ---- ---- of iodine absorption of, 121, 122 + +---- ---- ---- of saponification + +---- ---- ---- equivalents of, 118 + +---- ---- ---- of saponification value, 118 + +---- ---- ---- of specific gravity of, 117 of titre of, 122, 123 + +---- ---- ---- of unsaponifiable matter in, 119 + +---- ---- ---- of water in, 120 + +---- ---- ---- Yield of glycerine from, 116 + +Fatty acids, 9-13, 31 + +---- ---- Classification of, 10 + +---- ---- Direct combination with alkali of, 45, 46 + +---- ---- in soap, Determination of, 131 + +---- ---- ---- Examination of, 133, 134 + +---- ---- Preparation by acid process, 19-21 + +---- ---- ---- by ferment process, 16 + +---- ---- ---- by Twitchell's process, 20 + +---- ---- Saturated, 11 + +---- ---- Unsaturated, 11 + +Fennel oil, 100 + +Ferment process for preparation of fatty acids, 16 + +Ferments, action of, 15-18 + +Ficocerylic acid, 10 + +Filling soap, 65 + +Fish oils, 30 + +"Fitting," 51 + +Floating soap, 90, 91 + +Fluorides in soap, 88 + +Formaldehyde soap, 88 + +Framing soap, 66 + +Free alkali in soap, Estimation of, 132 + +---- caustic in soap, Neutralising, 66 + +---- fat in soap, Determination of, 133 + +---- fatty acids, Determination of, 117 + + +G. + +Geraniol, 108 + +Geranium oils, 101 + +Geranium-sur-rose oil, 101 + +Ginger-grass oil, 101 + +Glycerides, 7, 8 + +Glycerine, Chemically pure, 115 + +---- Crude, 113, 136-139 + +---- decolorisation, 115 + +---- distillation, 114 + +---- Distilled, 114 + +---- dynamite, 115 + +---- in soap, Determination of, 134, 135 + +---- manufacture, 111-114 + +---- saponification, 116 + +---- soaps, 89 + +---- Yield of, from fats and oils, 116 + +Glycerol determination, acetin method, 136 + +---- ---- bichromate method, 137, 138 + +---- in lyes, Estimation of, 135 + +Goa-butter, 33 + +"Graining-out," 50 + +Grease, Animal, 30 + +---- Bone, 30 + +---- Kitchen, 30 + +---- Skin, 30 + +Guaiac wood oil, 101 + + +H. + +Halphen's reaction, 134 + +Heliotropin, 108 + +Hemp-seed oil, 29 + +Hyacinth, 108 + +Hyænic acid, 10 + +Hydrated soaps, 48, 49 + +Hydrolysis accelerated by heat and electricity, 14, 15 + +---- accelerated by use of chemical reagents, 19-23 + +---- accelerated with acid, 19, 21 + +---- Enzymic, 15-18 + +---- of oils and fats, 13-23 + +---- of soap, 3 + +Hypogæic acid, 11 + + +I. + +Ichthyol soap, 89 + +Inoy-kernel oil, 37 + +Iodine absorption of rose oil, 130 + +---- absorption of oils and fats, 121,122: + +---- soap, 89 + +Ionone, 108 + +Isolinolenic acid, 12 + +Isovaleric acid, 10 + +Isovalerin, 8 + + +J. + +Jasmine, 109 + +Jecoric acid, 12 + + +K. + +Kananga oil, 98 + +Kapok oil, 32 + +"Kastilis," 88 + +Kokum butter, 33 + + +L. + +Lard, 25 + +Lauric acid, 10 + +Laurin, 8 + +Lavender oils, 101 + +Lemon-grass oil, 102 + +Lemon oil, 102 + +Lignoceric acid, 10 + +Lime oil, 102 + +---- saponification, 22 + +Linaloe oil, 102 + +Linalol, 109 + +Linalyl acetate, 109 + +Linolenic acid, 12 + +Linolic acid, 12 + +Linseed oil, 29 + +Lipase, 18 + +Liquoring of soaps, 64 + +Lyes, analysis of, 135 + +---- Determination of glycerol in, 135 + +---- Evaporation of, 112 + +---- Treatment of, 111, 112 + +Lysol soap, 89 + + +M. + +Mafura tallow, 35 + +Magnesia, Hydrolysis by, 22 + +Maize oil, 28 + +Margaric acid, 10 + +Margosa oil, 35 + +Marine animal oils, 30 + +---- soap, 49 + +Maripa fat, 34 + +Marjoram oil, 103 + +Medicated soaps, 86-90 + +Medullic acid, 10 + +Melissic acid, 10 + +Melting point, 130 + +Mercury soaps, 87 + +Milled toilet soaps, 78 + +Milling soap, 80, 81 + +---- soap-base, 54, 78 + +Mineral oil, saponifying, 58, 59 + +Mirbane oil or nitrobenzene, 109 + +Mixed glycerides, 8 + +Monoglycerides, 7 + +Monostearin, 7 + +Moringic acid, 11 + +Mottled soaps, 52, 53 + +---- ---- Pickling, 54 + +Moulds, Soap, 72, 85, 86 + +Mowrah-seed oil, 31 + +Musk (artificial), 109 + +Myristic acid, 8 + +Myristin, 8 + + +N. + +Naphthol soap, 89 + +Neroli Bigarade oil, 103 + +---- oil (artificial), 109 + +Neutralising free caustic in soap, 66, 80 + +Niam fat, 34 + +Nigre, 56 + +Nigres, Utilisation of, 56 + +Niobe oil or ethyl benzoate, 110 + +Nitrobenzene, 109 + + +O. + +Oeillet, 10 + +Oil, Andiroba, 32 + +---- Arachis, 28 + +---- Aspic (lavender spike), 96 + +---- Baobab-seed, 36 + +---- Bay, 97 + +---- Bergamot, 97 + +---- Bitter almond, 97 + +---- Bleaching palm, 41 + +---- Bois de Rose Femelle, 99 + +---- Cananga, 98 + +---- Candle-nut, 33 + +---- Carapa, 32 + +---- Caraway, 98 + +---- Cassia, 98 + +---- Castor, 30 + +---- Cayenne linaloe, 99 + +---- Cedarwood, 98 + +---- Cinnamon, 98 + +---- Citronella, 99 + +---- Clove, 99 + +---- Cocoa-nut, 25, 26 + +---- Cohune-nut, 34, 35 + +---- Concrete orris, 100 + +---- Coprah, 25, 26 + +---- Cotton-seed, 27, 42 + +---- Curcas, 33 + +---- Eucalyptus, 100 + +---- Fennel, 100 + +---- Geranium, 101 + +---- Ginger-grass, 101 + +---- Guaiac-wood, 101 + +---- Hemp-seed, 29 + +---- Inoy-kernel, 37 + +---- Kananga, 98 + +---- Kapok, 32 + +---- Lemon, 102 + +---- Lemon-grass, 102 + +---- Lime, 102 + +---- Linaloe, 102 + +---- Linseed, 29 + +---- Maize, 28 + +---- Margosa, 35 + +---- Marjoram, 103 + +---- Mowrah-seed, 31 + +---- Neroli Bigarade, 103 + +---- Olive, 26 + +---- Olive-kernel, 27 + +---- Orange, 163 + +---- Palm, 27, 41 + +---- Palm-nut, 26 + +---- Palmarosa, 103 + +---- Patchouli, 103 + +---- Peppermint, 103, 104 + +---- Persimmon-seed, 36 + +---- Peru-balsam, 104 + +---- Petit-grain, 104 + +---- Pongam, 35 + +---- Refining cotton-seed, 42 + +---- Rose, 105 + +---- Rosemary, 105 + +---- Safflower, 33, 34 + +---- Sandalwood, 105, 106 + +---- Saponifying mineral, 58, 59 + +---- Sassafras, 106 + +---- Sesame, 28, 29 + +---- Star-anise, 96 + +---- Sunflower, 29 + +---- Thyme, 106 + +---- Verbena, 106 + +---- Vetivert, 106-107 + +---- Wheat, 36 + +---- Wild mango, 36 + +---- Wintergreen, 107 + +---- Ylang-ylang, 107 + +Oils and fats, Constitution of, 6, 7 + +---- ---- Examination of, 117-123 + +---- ---- Hydrolysis of, 13-22 + +---- Fish and marine animal, 30 + +---- Lavender, 101 + +---- Refractive Index of, 122 + +---- treatment of vegetable, 43 + +Oleic acid, 11 + +---- ---- into solid acids, Conversion of, 11, 12 + +Olein, 8, 9, 31 + +---- Cocoa-nut, 31 + +---- Palm-nut, 31 + +Oleodidaturin, 8 + +Oleodipalmitin, 8 + +Oleodistearin, 8 + +Oleopaimitostearin, 8 + +Olive-kernel oil, 27 + +Olive oil, 26 + +Open-piling soap, 71 + +Optical rotation, 127 + +Orange oil, 103 + +Orchidée, 107 + +Orris oil, concrete, 100 + + +P. + +Palm oil, 27, 41 + +---- ---- Bleaching, 41 + +Palmarosa oil, 103 + +Palmitic acid, 10 + +Palmitin, 8 + +Palmitodistearin, 8 + +Palm-nut oil, 26 + +Pasting or saponification, 49 + +Patchouli oil, 103 + +Patent textile soaps, 94 + +Pearl-ash, Analysis of, 125, 126 + +Peppermint oil, 103, 104 + +Perfumer's soaps, 77, 78 + +Perfumes, Artificial and synthetic, 107-110 + +---- Soap, 95-110 + +Perfuming soaps, 94 + +Persimmon seed oil, 36 + +Peru-balsam oil, 104 + +Petit-grain oil, 104 + +Phenols, Determination of, 129 + +Physetoleic acid, 11 + +Phytosterol in unsaponifiable matter, 120 + +Pickling mottled soap, 54 + +Pisangcerylic acid, 10 + +Polishing soaps, 94 + +Pongam oil, 35 + +Potash, Carbonate, 39, 125, 126 + +---- Caustic, 89, 123 + +Potassium chloride, 126 + +---- Determination of, 126, 132 + +Powders, Soap, 94 + +Psyllostearylic acid, 10 + + +R. + +Rancidity, 18, 24 + +Rapic acid, 11 + +Refining cotton-seed oil, 42 + +Refractive index of oils and fats, 122 + +Remelted soaps, 77, 78 + +Resinate of soda, 43, 44 + +Ricinoleic acid, 13 + +Ricinolein, 8 + +Rose oil, 105 + +---- ---- (artificial), 110 + +Rosemary oil, 105 + +Rosin, 37, 38, 43, 44, 55 + +---- Bleaching, 43 + +---- Determination of, 133, 134 + +---- treatment, 43, 44 + + +S. + +Safflower oil, 33, 34 + +Safrol, 110 + +Salt, 39, 126 + +---- Determination of, 124, 125, 126, 132 + +Sandalwood oil, 105, 106 + +Santalol, 110 + +Saponification, 13-22, 49 + +---- accelerated by heat and electricity, 14, 15 + +---- accelerated by use of chemical reagents, 19, 23 + +---- accelerated with Twitchell's reagent, 20 + +---- Acid, 19, 21 + +---- Aqueous, 14 + +---- by ferment process, 20 + +---- equivalent, 118 + +---- Glycerine, 116 + +---- Lime, 22 + +---- under pressure, 47 + +---- value, 118, 128 + +Saponifying mineral oil, 58, 59 + +Sassafras oil, 106 + +Saturated acids, 11 + +Scouring soaps, 92, 93 + +Sesame oil, 28, 29 + +Settled soap, Treatment of, 60-76 + +Shaving soaps, 91 + +Shea butter, 31 + +Silicate of soda in soap, 65 + +Silicates of soda and potash, 127, 138 + +Silk scouring soaps, 93 + +---- dyer's soap, 93, 94 + +Slabbing soap, 68 + +Soap, Albumen in, 90 + +---- Analysis of, 130-35 + +---- Bar, 54, 55 + +---- Barring, 68 + +---- -base, Milling, 54, 78 + +---- Biniodide, 87 + +---- Birch-tar, 88 + +---- Borax, 88 + +---- Boric acid in, 88 + +---- ---- ---- ---- Determination, 135 + +---- Carbolic, 88 + +---- Classification of, 45 + +---- Cleansing, 60, 61 + +---- Coal-tar, 88 + +---- Cold process, 46, 47 + +---- Compressing, 83, 85 + +---- Cooling, 74-76 + +---- Crutching, 63 + +---- Curd, 52 + +---- Curd mottled, 53 + +---- Definition of, 1, 2 + +---- Detergent action of, 4, 5 + +---- Determination of carbolic acid in, 134 + +---- ---- of fatty acids in, 131 + +---- ---- of free alkali in, 132 + +---- ---- of free fat in, 133 + +---- ---- of glycerine in, 134, 135 + +---- ---- of total alkali in, 131 + +---- ---- of water in, 133 + +---- Drying, 71, 78-80 + +---- Electrical production of, 59 + +---- Ether, 90 + +---- Examination of fatty acids 133, 134 + +---- Filling, 65 + +---- Fluorides in, 90 + +---- formaldehyde, 88 + +---- frame, 66 + +---- framing, 66 + +---- from fatty acids, 45, 46 + +---- Glycerine, 89 + +---- Hydrated, 48, 49 + +---- Hydrolysis of, 3 + +---- Ichthyol, 89 + +---- Iodine, 89 + +---- Lysol, 89 + +---- Marine, 49 + +---- Milling, 80, 81 + +---- Monopole, 94 + +---- Mottled, 52, 53 + +---- moulds, 72, 85, 86 + +---- Naphthol, 89 + +---- Neutralising, colouring and perfuming, 66, 80, 82 + +---- Open and close piling, 71 + +---- perfumes, 95-110 + +---- Pickling mottled, 54 + +---- powders, 94 + +---- Properties of, 2 + +---- Salicylic acid, 88 + +---- Settling of, 55 + +---- Slabbing, 68 + +---- Soft, 41 + +---- Stamping, 71, 72, 85, 86 + +---- Sulphur, 89 + +---- Terebene, 90 + +---- Thymol, 90 + +---- Transparent, 57, 58 + +---- Treatment of settled, 60-76 + +---- Yellow household, 54, 55 + +Soap-making, 45-59 + +---- ---- Blue and grey mottled, 53 + +---- ---- "Boiling-on-strength," 51 + +---- ---- Cold process, 46, 47 + +---- ---- Combination of fatty acids with alkali, 45, 46 + +---- ---- Curd, 52 + +---- ---- Curd, Mottled, 53 + +---- ---- "Fitting," 51 + +---- ---- "Graining-out" or separation, 50 + +---- ---- Hydrated, 49 + +---- ---- "Pasting" or saponification, 49 + +---- ---- Soft, 48 + +---- ---- Transparent, 57, 58 + +---- ---- under pressure, 47 + +Soaps, Calico-printer's, 93 + +---- Disinfectant, 66 + +---- Floating, 90, 91 + +---- Liquoring of, 64, 65 + +---- Medicated, 86-90 + +---- Milled toilet, 78 + +---- Miscellaneous, 94 + +---- Perfumer's, 77, 78 + +---- Polishing, 94 + +---- Remelted, 77, 78 + +---- Scouring, 92 + +---- Shaving, 91 + +---- Silicating, 65 + +---- Silk dyer's, 93, 94 + +---- Textile, 91-94 + +---- Toilet, 77, 78 + +---- Woollen dyer's, 92 + +Soap-stock, 40 + +Soda ash, 39, 124, 125 + +---- ---- Caustic, 39, 125 + +---- Carbonate, 39, 124, 125 + +---- Caustic, 39, 123 + +---- Resinate, 43, 44 + +Soft soap-making, 48 + +Solidifying-point, 130 + +Specific gravity, Determination of, 117, 127 + +Stamping soap, 71, 72, 85, 86 + +Starch, Detection of, 121, 135 + +Steapsin, 18 + +Stearic acid, 10 + +Stearin, 8, 9 + +Stearine, Cotton-seed, 28 + +Stearodipalmitin, 8 + +Sulphides and sulphites, Determination of, 125 + +Sulphur soap, 89 + +Sunflower oil, 29 + +Superfatting material, 83 + +Synthetic perfumes, 107-110 + + +T. + +Table of caustic potash solutions, 151 + +---- of caustic soda solutions, 149, 150 + +---- of comparative densities, 147 + +---- of thermometric equivalents, 148 + +Tablet soap, 55 + +Talc, 65 + +Tallow, 24 + +---- Borneo, 32 + +---- Chinese vegetable, 31 + +---- Mafura, 35 + +Tangkallah fat, 37 + +Tariric acid, 12 + +Telfairic acid, 12 + +Terebene, 110 + +---- soap, 90 + +Terpineol, 110 + +Textile soaps, 91-94 + +---- ---- Patent, 94 + +Theobromic acid, 10 + +Thyme oil, 106 + +Thymol soap, 90 + +Tiglic acid, 11 + +Titre test, 122, 123 + +Toilet soaps, 77, 78 + +---- ---- Compressing, 83, 85 + +---- ---- Milled, 78 + +---- ---- Milling, 80, 81 + +---- ---- Stamping, 85, 86 + +Transparent soaps, 57, 58 + +Treatment of animal fats, 43 + +---- ---- bone fat, 43 + +---- ---- lyes, 111, 112 + +---- ---- rosin, 43 + +---- ---- settled soap, 60-76 + +---- ---- Vegetable oils, 43 + +Trèfle, 107 + +Triglycerides, 7, 8 + +Trilaurin, 9 + +Triolein, 9 + +Tripalmitin, 9 + +Tristearin, 7, 9 + +Twitchell's process, 22 + + +U. + +Unsaponifiable matter, Constitution of, 119, 120 + +---- ---- Determination of, 119 + +Unsaturated acids, 11 + +Utilisation of nigres, 56 + + +V. + +Vanillin, 110 + +Vegetable oils, Treatment of, 43 + +---- tallow, Chinese, 31 + +Verbena oil, 106 + +Vetivert oil, 106 + +Violet soap, 54 + +Volhard's method for chloride determination, 132 + + +W. + +Waste fats, 30 + +Water, 39 + +---- ---- in fats, Determination of, 120 + +---- ---- in soap, Determination of, 133 + +Wheat oil, 36 + +Wild mango oil, 36 + +Wintergreen oil, 107 + +Wool scouring soaps, 92 + +Woollen dyer's soap, 92 + + +Y. + +Ylang-ylang oil, 107 + + +Z. + +Zinc oxide, Hydrolysis by, 22 + +---- soap, 87 + +THE ABERDEEN UNIVERSITY PRESS LIMITED + + + + + STEVENSON & HOWELL'S + + SPECIALITIES FOR + + Soapmakers & Wholesale Perfumers. + + + ESSENTIAL OILS + + OF GUARANTEED PURITY. + + + Almonds, Bay Leaves, Bergamot, Caraway, + Cananga, Camomile, Cascarilla, Cassia, + Cedar Wood, Cinnamon, Citronella, Cloves, + Coriander, Eucalyptus Globulus, Fennel, Sweet, + Geranium -- _Algerian_, _Bourbon_, _East Indian_, + _French_, _Spanish_ & _Turkish_, + Kuromoji, Lavender, Lemon, Lemon-Grass, + Limes, Neroli, Myrbane, Orange Sweet & Bitter, + Otto of Rose, Patchouli, Palmarosa, Pimento, + Petit-Grain, Rosemary, Sandal Wood, Sage, + Sassafras, Spearmint, Thyme, Wintergreen + Ylang-Ylang., &c. + + + TOILET SOAP PERFUMES + + FINEST QUALITY + + Almond, Bay Rum, Brown Windsor, Cologne, + Florida, Frangipanni, Heliotrope, Hyacinth, Lilac, + Lily of Valley, Oriental, Parisian, Walnut Leaf, + Wood Violet, &c. + + + ARTIFICIAL PERFUMES. + + Aubepine, Cuir de Russiè, Coumarin, Crategine, + Heliotropine, Lilac, Musk, Nerolin, Terpineol, + Vanillin, Yara-Yara, &c. + + SOAP COLOURS, Dark Blue, Rose Pink, + Indian Brown, Carbolic Pink & Red, Manchester Yellow. + &c. &c. + + _SPECIALITY_:--RELIABLE CHLORPHYL. + + STANDARD WORKS + + SOUTHWARK ST. LONDON. S. E. + + GLASGOW OFFICE 128, HOPE ST. + + + + + ___________________________________________________ + | | + | FASTEST AND STRONGEST | + | | + | COLOURS FOR SOAP | + | | + | In all shades, alkali-proof. | + | | + | OIL SOLUBLE COLOURS FOR | + | OIL AND BENZINE SOAPS. | + | | + | BLACKS | + | | + | And all colours soluble in Oil, Wax and Turps for | + | | + | BOOT POLISH. | + | | + | =============================================== | + | | + | WILLIAMS BROS. & CO., HOUNSLOW. | + |___________________________________________________| + + TEXTILE + + SOAPS AND OILS. + + Handbook on the Preparation, Properties and Analysis + of the Soaps and Oils used in Textile Manufacturing, + Dyeing and Printing. + + BY + GEORGE H. HURST, F.C.S., + + Author of "Soaps," "Lubricating Oils, Fats and Greases," etc. + + CONTENTS. + + Methods of Making Soaps--Special Textile Soaps--Relation of Soap + to Water for Industrial Purposes--Soap Analysis--Fat in + Soap--Animal and Vegetable Oils and Fats--Vegetable Soap, Oils + and Fats--Glycerine--Textile Oils. + + Price 5s. net (Post Free, 5s. 4d. Home; 5s. 6d. Abroad). + + Published by + + SCOTT, GREENWOOD & SON, + 8 BROADWAY, LUDGATE HILL, LONDON, E.C. + + + + + + WILLIAM TULLOCH & CO., + + 30 George Square, Glasgow, + And at 9 Great Tower Street, London, E.C., + 14 No. Corridor, Royal Exchange, Manchester. + + GLYCERINE, + + CRUDE, DYNAMITE, INDUSTRIAL, CHEMICALLY PURE. + + All Kinds of Chemicals for Soap and Explosives Makers. + + NITRATE OF LEAD, FARINAS, STARCHES, GUMS. + + TWITCHELL PROCESS OF + GLYCERINE EXTRACTION. + + HIGHEST + + Degree of Decomposition. + + LOWEST + + Cost for Installation and Working. + + BEST + + Qualities of Fatty Acids, Glycerine, Stearine and Soap. + + For Samples and information, apply to + + WM. TULLOCH & CO., + + 30 GEORGE SQUARE, GLASGOW. + General Representatives for United Kingdom and Colonies. + + SUDFELDT & CO., MELLE (HANOVER, GERMANY). + + JOSLIN SCHMIDT & CO., + + CINCINNATI, OHIO, U.S.A. + + + + + THE CHEMISTRY OF + + Essential Oils + + AND + + Artificial Perfumes. + + BY + + ERNEST J. PARRY, B.Sc. (Lond.), F.I.C., F.C.S. + + 552 Pages. Second Edition, Revised and Enlarged. Demy 8vo. 1908. + + CONTENTS. + + Chapters I. ~The General Properties of Essential Oils.~ Physical + Properties, Optical Properties, Table of Specific Gravities, + Refractive Indices and Rotation.--II. ~Compounds occurring in + Essential Oils.~ (I.) 1. TERPENES--Pinene, Camphene, Limonene, + Dipentene, Fenchene, Sylvestrene, Carvestrene, Phellandrene, + Terpinolene, Terpinene and Thujene. 2. + SESQUITERPENES--Cadinene, Caryophellene, Cedrene, Clovene, + Humulene, Ledene, Patchoulene, and Sesquiterpene from Oils of + Cannabis Indica, Table, b.p., sp.-gr., opt. Rot., etc., of + same. (II.) THE CAMPHOR SERIES--Borneol, Isoborneol, Camphor, + Fenchyl Alcohol, Fenchone, Thujyl Alcohol, Thujone, Terpineol, + Cineol, etc., etc. (III.) THE GERANIOL AND CITRONELLOL + GROUP--Coriandrol, Nerolol, Rhodinol, Geraniol, Linalol, + Citrenellol, etc., Table, b.p., sp.-gr., Ref. Index, etc. (IV.) + BENZENE COMPOUNDS--Cymene, Phenols and their Derivatives, + Phenols with Nine Carbon Atoms, Phenols with Ten Carbon Atoms, + Alcohols, Aldehydes, Ketones, Acids, etc. (V.) ALIPHATIC + COMPOUNDS--Alcohols, Acids, Aldehydes, Sulphur Compounds, + etc.--III. ~The Preparation of Essential Oils.~ Expression, + Distillation, Extraction, Table of Percentages.--IV. ~The + Analysis of Essential Oils.~ Specific Gravity, Sprengel Tube + Method, Optical Methods, Melting and Solidifying Points, + Boiling Point and Distillation, Quantitative Estimations of + Constituents, the Determination of Free Alcohols, Absorption + Processes.--V. ~Systematic Study of the Essential Oils.~ Oils of + the Gymnosperms, Tabulated Angiosperms. (I.) WOOD OILS.--Cedar + Oils, Oils of Turpentine, American Turpentine, French Oil of + Turpentine, German, Russian, and Swedish ditto, Table of + Activities of same, Juniper Wood Oil. (II.) FRUIT + OILS.--Juniper Berry Oil, Fir Cone Oils. (III.) LEAF + OILS.--Thuja Oil, Oil of Savin, Cedar Leaf Oil, Pine Needle + Oil, Cypress Leaf Oil, Table of Pine Oils (after Schimmel). + OILS OF THE ANGIOSPERMS--(I.) MONOCOTYLEDONS. (II.) + DICOTYLEDONS: (_a_) MONOCHLAMYDEÆ--(_b_) GAMOPETALÆ--(_c_) + POLYPETALÆ--VI. ~Terpeneless Oils.~ Terpeneless Oil of Lemon, + Tables of sp.-gr. and Rotn. of several Terpeneless Oils, + Terpeneless Oil of Orange, Ditto of Caraway, of Lavender, Table + of sp.-gr. and Rotn. of Commercial Samples of Oils.--VII. ~The + Chemistry of Artificial Perfumes.~ Vanillin, Coumarin, + Heliotropin, Aubepine or Hawthorn, Ionone, Specification of + Patents for Preparation of Ionone, for Artificial Violet Oil, + Artificial Musk, Specification of Patent of Musk Substitute, + Artificial Neroli, Artificial Lilac, Artificial Hyacinth, + Artificial Lemon Oil, Artificial Rose Oil, Niobe Oil, + Bergamiol, Artificial Jasmin Oil, Artificial Cognac + Oil.--~Appendix.~ Table on Constants of the more Important + Essential Oils.--~Index.~ + + Price 12s. 6d. net (Post Free, 13s. Home; + 13s. 6d. Abroad). + + PUBLISHED BY + + ~SCOTT, GREENWOOD & SON,~ + + ~8 BROADWAY, LUDGATE HILL, LONDON E.C.~ + + + + + + +End of the Project Gutenberg EBook of The Handbook of Soap Manufacture, by +W. H. Simmons and H. A. Appleton + +*** END OF THIS PROJECT GUTENBERG EBOOK THE HANDBOOK OF SOAP MANUFACTURE *** + +***** This file should be named 21724-8.txt or 21724-8.zip ***** +This and all associated files of various formats will be found in: + https://www.gutenberg.org/2/1/7/2/21724/ + +Produced by Ben Beasley, Richard Prairie, Josephine Paolucci +and the Online Distributed Proofreading Team at +https://www.pgdp.net. 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