Stearic Acid

(ste-arik.) [From Gr. stear, fat.] (Chem.) A solid substance with acid properties, obtained by the saponification of stearine (C114H110012), one of the proximate principles of fats. Stearine may be obtained from mutton fat by melting it and mixing it with ether. When the whole has cooled, stearine crystallizes out. If the stearine be boiled with a strong solution of caustic potash, a soap is formed, and when this is decomposed by an acid, S. A. and glycerine are obtained. For commercial purposes, S. A. is obtained by a different proce , which need not here be detailed. S. A. is insipid and inodorous; after having been melted by heat, it solidifies, at 158° Fahr., into white, brilliant needles, grouped together. It is insoluble in water, but di olves in all proportions in boiling anhydrous alcohol; kindled in the open air, it burns like wax. In the manufacture of candles, it is melted in a silver pan, because other metals would color it; when at a proper temperature it is poured into the moulds, and forms a candle closely resembling one made with wax. If the temperature during fusion is raised too high, the acid crystallizes, and becomes brittle; two qualities by which it is rendered, nearly unsalable, but which may be prevented by the addition of a little wax, magnesia, or French chalk. Form. HO.C36 H3503(starnz,) in Minnesota, a central co.; area, 1,380 sq. m.; C. St. Cloud. Pop. 14,206. (ste'a-tit.) (From Gr. stear, tallow.] SOAPSTONE, q. v.-It is used in the manufacture of por ce lain; also for taking greasy spots out of silk and woollen stuffs; and it is employed in polishing gypsum, serpentine, and marble. [s. 855]