SNYDERS, or SNEYDERS, FRANCIS, a Belgian artist, celebrated for his powers as an animal-painter, was b. at Antwerp in 1579, and was formed in the school of Henry van Baden. Originally, he confined himself exclusively to painting fruits, and worked with Rubens. In his pictures, with figures by Rubens, Jordaens, don thorst, and Micro velt, it is difficult to discover any difference of touch. For Philip HI. of Spain lie exe cuted several hunting and battle pieces. Snyders knew how to give expression to the passions of the lower creation, and his bear, wolf, and boar fights are scarcely surpassa ble. The best specimens of the artist are contained in the galleries of Vienna, Munich, and Dresden, but there are also some fine pictures of his in private English collections. Snyders died at Antwerp in 1657.
SOAP (Lat. sapo(n), Welsh sebon —the Romans considered soap to be a Celtic inven tion). This well-known material, according to Pliny, first became known to the Romans by their conquest of Gaul. There arc some notices of it in the English version of the Bible, but it is believed that the words borith and nether, there rendered into soap, really mean potash and soda.
The chemical composition of soap may be explained as follows: The fixed fatty bodies, stearine, palmitine, and oleine (we do not inclnde margarine, for it is now generally admitted that the fat to which this name was applied is merely a mixture of stearine and pahnitine), when heated with alkaline solutions, undergo the remarkable change known under the title saponification, or conversion into soap, during which process the fats yield up a clear viscid liquid, which, from its sweetness, is termed glycerine (q.v.). The nature of this change may be ascertained by decomposing the soap that is thus formed, and which exists as a homogeneous transparent mass, freely soluble in warm water, by the addition of some acid, such as tartaric or hydrochloric, which combines with the alkali, and forms a soluble compound with it. 'A fatty matter separates in flakes, which melt on the application of heat, and form an oily layer on the surface of the fluid. This substance, when cold, is found to be very different from the original fat. It has acquired a strongly acid reaction, as may he ascertained by applying test-paper to it in its melted state, and it is freely soluble in alcohol, the solution being strongly acid. It
at once forms a clear solution in hot alkaline liquids, while the original fat would under similar conditions have formed a milky-looking fluid. It is, in fact, a true acid, capable of forming salts, the potash and soda salts being known as soft-soap and ha-rd-soap, which have been thus generated out of the elements of the neutral fat under the influence of the alkali. Steariue, when thus treated, yields stearic acid palmitine yields pabwitic acid (q.v.); and oleine, oleic acid (q.v.); while common fat. which is a mixture of the three above-named fats, affords, on saponification with an alkali, and subsequent decomposition of the soap, a mixture of the three fatty acids.
The term soap is sometimes extended in meaning, so as to include compounds of the fatty acids with other bases besides the alkalies, e.g., lime, bacyta, magnesia, etc.; but these compounds being insoluble are inapplicable to the purpose of cleaning. The true soaps owe their cleaning power to their solubility, and their attraction for the matters *that ordinarily constitute "dirtiness." The presence of a portion of free alkali increases the detergent power, especially in the case of greasy matter.
Mannfacture.—In this country, and in the n. of Europe generally, hard-soap is made from tallow, palm-oil, bone grease, and kitchen fat, by boiling to saturation with caus tic-soda. Cocoa, palin nut, and some other oils are occasionally used, chiefly in imitat ing sup:Tior soaps, and the only other ingredient of consequence is rosin, the residuum of the distillation of rough turpentine. In the s. of Europe, coarse olive-oil is the staple material, and from this is produced the marbled soap known as "Marseilles." The soap-maker first dissolves in boiling water 6 to 8 cwt. of crude soda ash (see SODA) in a east-iron circular vessel (contents may be 1000 gals.), furnished with a steam pipe in its center. He then adds half the weight of pure caustic lime, and boils the mixture. When the lime has rendered the soda caustic, the boiling is discontinued, subsidence takes place, and the lye is ready for use.