538 



SNUFF 



Snuff. See TOBACCO. 



Snyders, FRANCIS, a Flemish painter, born at 

 Antwerp in 1579, studied under Van Breughel and 

 Van Balen. Originally he confined hiniHelf to 

 painting fruit*, game, vegetables, and other typical 

 models of -i ill life; but under the influence of 

 Kultena, for whom, as well as for Jordaens, he fre- 

 i|iiciu I v painted aniinala and still-life subjects to go 

 in i heir larger pictures, he cultivated more especi- 

 ally the (minting of animals. His bear, wolf, and 

 boar lights have hardly ever been surpassed. He 

 painted a stag-hunt and similar hunting subjects 

 for Philip III. of Spain. Snyders died at Antwerp 

 in August 1637. 



Sonne, SIB JOHN, an English architect, born 

 of humble parentage at Reading on 10th Septem her 

 1 7 ">.'). He managed to get trained as an architect, 

 and, having gained the travelling scholarship of 

 the Royal Academy, spent three years (1777-80) 

 in Italy. After his return home he secured several 

 official appointments e.g. architect to the Bank 

 of England, St James's Palace, Office of Woods and 

 Forests anil was elected professor of Architecture 

 at the Royal Academy ( 1806). He designed numer- 

 ous country-houses in the eastern counties and 

 parts of public buildings (Bank of England) in 

 London, showing in his plans considerable in- 

 genuity, but an uncertain taste, and frequently a 

 lack of harmony in his completed plans. At his 

 death, in London on 20th January 1837, he be- 

 queathed his own house in Lincoln's Inn Fields, 

 and the valuable art and antiquarian museum it 

 contained, including pictures by Hogarth, Rey- 

 nolds, Turner, models by Flaxman, the MS. of 

 Tasso'g Gerusalemme Liberata, &c., to the nation. 

 He published amongst other books a set of folio 

 plates of Public and Private Buildings ( 1828), and 

 a Description ( 1832) of his own house and museum. 



See the Memoir by J. Britton (1834), and the Art 

 Journal (188i). 



Soap is the term applied to that class of com 

 pounds formed when alkalies act upon fats or fatty 

 acids. Chemically it includes also the insoluble 

 compounds formed from metallic oxides, as lime, 

 litharge, \T. ; but industrially it is confined to the 

 coni|Hiunds of soda and potash. Soap is first 

 mentioned by Pliny, who states that it was pre- 

 pared from goat's tallow and beech-tree nshes, and 

 was employed for giving brilliance to the hair. 

 The excavations at Pompeii brought to ligjit a 

 complete M>ap-making establishment, containing 

 some well-preserved soap. The industry, however, 

 advanced very slowly, and it is only within com- 

 paratively recent years that it has really flourished. 

 The most important discoveries which have assisted 

 it- development and led to its present enormous 

 proportions are Chevreul's researches on the con- 

 titntion of fats and Leblanc's process for the 

 manufacture of soda on a large scale. It has also 

 been stimulated in Britain by the repeal in 1853 of 

 the duty (amounting to from'ld. to 3d. per Ib. ), first 

 imposed in 1711. ( 'lievreul showed" that the neutral 

 fata are mix turns of ' glyrerides,' consisting of gly- 

 cerine combined with the elements of certain fatty 

 acids. In the process of saponification the fat is 

 decomposed, the fattv acids combining with the 

 alkali to form soap, while the glycerine is set free. 



Soaps are distiiigiuxhed as 'hard' (soda-soaps) 

 and 'soft' (potash-soaps). They have a charac- 

 teristic taste, and an; soluble in water and in 

 alcohol. When agitated with water a 'lather' is 

 produced, and when their hot aqueous solutions 

 are allowed to cool jellies are formed. Salt pre- 

 cipitates them from their solutions, but in the case 

 or a potash-soap the bulk is converted into a soda- 

 soap I iy double decomposition. The cleansing power 

 of soap lias not been satisfactorily explained ; it is 



SOAP 



generally supposed to be due to the ' hydrolysis,' 

 or partial decomposition into free alkali and in- 

 soluble acid-soap which takes place when the soap 

 is dissolved in water. Dittmar considers that the 

 cleansing power of soap may be attributed to ' the 

 inherent property of its solution to emulsionise 

 fats,' which seems a more plausible theory. 



The principal fate and oils employed in the 

 manufacture of soap are tallow, greases, palm-oil, 

 lard, cocoa-nut oil, and olive-oil for ' hard ' soaps ; 

 distilled fatty acids are also used, and rosin in con- 

 junction with tallow, &c. For ' soft ' soaps linseed- 

 oil, castor-oil, and fish-oils are used, as well as 

 some of those already mentioned. The caustic 

 alkalies, potash and soda, were formerly prepared 

 from the carbonates by the soap-maker himself, 

 but are now almost entirely procured from the 

 soda-manufacturer. 



The following processes, arranged in order of 

 simplicity, are those used in the manufacture. 



( 1 ) The direct union of free fatty or resinous 

 acids and alkalies. This process is seldom used. 

 The fatty acid (e.g. oleic) is run into a steam 

 jacketed pan, provided with a mechanical agitator, 

 and raised to about 300 F. by super-heated steam. 

 A strong solution of the necessary quantity of 

 alkali is then added, and the whole well stirred. 

 The mixture is allowed to stand for some time, 

 some water added, again stirred, and removed to 

 cooling-frames. 



(2) Treatment of fate with definite quantities 

 of alkali, the glycerine remaining with the soap ; 

 known as the 'cold process." Given weights of 

 fat are melted at the lowest possible tempera- 

 ture, and mechanically mixed in a pan with a 

 definite quantity of caustic lye of known strength, 

 just sufficient to effect complete saponification. 

 After standing for from one to four days, accord- 

 ing to the quantity, the soap is hard enough for use. 

 This process possesses the advantages of economy 

 and retention of the glycerine. Soaps made in this 

 way, however, are liable to contain free alkali, 

 and of necessity contain also the impurities of the 

 soda. 



(3) Treatment of fats by boiling with indefinite 

 quantities of alkaline lye. This process is the most 

 important of the three, and will now be described 

 as it is carried out for ' hard soaps.' 



Hard Soaps constitute the great bulk of the 

 soups n-i-il, and may be divided into three varieties 

 curd, mottled, and yellow. The general method 

 is the same for the three. The vessel used (called 

 the 'copper') is made of wrought-iron plates 

 riveted together, and is provided with coils for 

 supplying open and close steam. These ' coppers ' 

 are generally of circular form, and capable of turn- 

 ing out from 20 to 30 tons of soap at one operation, 

 although some of them are much larger. In the 

 first stage (called 'killing the goods') a quantity 

 of the fat is melted in the 'copper,' weak caustic 

 lye added, and the steam turned on. The mass 

 becomes pasty after some time, and the boiling is 

 continued, and fat and lye added, until a sample 

 appears somewhat firm, and has very little or no 

 caustic taste. In the second stage ('cutting the 

 soap ' or ' salting ') the water is separated from the 

 soap (the trailing beinj; continued) by the cautious 

 addition of common salt, or strong brine, until 

 clear liquor runs from a small sample taken out. 

 After Htanilinj; for a few hours the 'spent lye' 

 (containing the bulk of the glycerine of the fat, 

 common salt, and the impurities of the caustic 

 soda) is removed. In the third operation ('clear 

 trailing') the granulated soap is boiled for two to 

 three hours with fresh lye, in order to cause more 

 complete saponification, and to remove the brine 

 retained by the soap. After settling, the lye U 

 removed, and may be used for the treatment of 



