Dec. 1, 1864.] THE TECHNOLOGIST. 



ON CHEMISTRY APPLIED TO THE ARTS. 199 



also that oxide of glyceryle, a9 it is liberated from the fatty acids, com- 

 bines with water and forms glycerine. He further showed that when 

 fatty matters were saponified, the change consisted in the substitution, 

 for the oxide of glyceryle, of the oxide of sodium or soda in ordinary 

 hard soaps, of the oxide of potassium and potash in soft soaps, of oxide 

 of lime, baryta, or lead in insoluble soaps. You will easily conceive the 

 pride of M. Chevreul when, forty years later, M. Berthelot effected the 

 synthesis of the fatty matters, the analysis of which M. Chevreul had 

 published in 1811. This he accomplished by heating in sealed tubes, 

 at a temperature of 520 deg. for several hours, one, two or three equiva- 

 lents of each of the above acids with one equivalent of glycerine, leaving 

 the mixture to cool, and then boiling it in a vessel with water and lime, 

 when the excess of fatty acids not combined during the experiment were 

 removed by the lime, leaving the neutral fatty matter, which was dissolved 

 by ether, and thus obtained in a state of purity. By this interesting series 

 of researches, M. Berthelot has not only reconstituted neutral fatty 

 matters, but showed that the oxide of glyceryle was triatomic — that is, 

 that one equivalent of the oxide would neutralise three equivalents of 

 the acid, whilst it required three equivalents of soda to produce a neutral 

 stearate with three equivalents of stearic acid — 



Stearic acid, 3 (C 98 H 09 6 ), Glycerine, C e H 8 6 — 4 HO 

 Stearic acid, 3 (C 08 H 66 6 ) + 3 Soda NaO — 3 HO. 



In fact, the researches of this eminent chemist on the synthesis of organic 

 substances have effected a complete revolution in the last few years in 

 that branch of organic chemistry. 



I shall now proceed to give a rapid outline of the properties of these 

 substances. 



Stearic acid is a white crystalline substance, fusible at 158 deg. F., 

 soluble in alcohol and ether, insoluble in water, and saponified by 

 alkalies. 



Margaric acid is a solid crystalline substance, presenting the same 

 properties as stearic, excepting that its fusing point is 140 deg. 



Oleic acid is a fluid remaining in that 6tate even at several degrees 

 below the freezing point of water, and is also soluble in alcohol and 

 ether, but not in water. 



Glycerine, or the sweet principle of oils, was discovered in 1779, by 

 Scheele, who extracted it in boiling oil of sweet almonds with oxide of 

 lead, which, combining with the fatty acids, liberated the oxide of 

 glyceryle, and this, in combining with water, formed glycerine. In con- 

 sequence of the numerous applications of glycerine in medicine, the 

 French have manufactured this substance on a large scale from the 

 liquors in which they have saponified their fatty matters into soap ; but 

 the purest and most extensive supply is furnished by Price's Patent 

 Candle Company. In the course of this lecture I will give you a de- 

 scription of its preparation, as carried out at their works. Glycerine is 

 a colourless, syrupy fluid, of sweet taste, and sp. gr. 1"28, highly soluble 



