142 OILY OXIDES, SAPONIFIABLE. 



elain. Some fatty bodies yield oils having different properties 

 from elain. Those that have been examined by Chevreul are 

 Phocenin, Butyrin, and Hircin. The mode of obtaining these 

 bodies and their properties have been already described in the 

 Chemistry of Inorganic Bodies, (Vol. ii. 35.) 



Chevreul analyzed the stearin and elain from different fatty 

 bodies, as human fat, hog's lard, mutton suet, &c. He found 

 them all compounds of carbon, hydrogen, and oxygen. But the 

 proportions were not the same in all. Whether this difference 

 was owing to any diversity in the various stearins and elains, or 

 to the presence of foreign bodies in greater or smaller quantity, 

 we have no means of determining. 



It has been ascertained that stearin is a compound of stearic 

 or margaric acid and glycerin, which performs the part of a base. 

 Stearic acid has been shown by the analytical researches of Messrs 

 Redtenbacher, Varrentrapp, and Bromeis * to be C 68 H 66 O 3 

 = 64-25. 



In its common state it is a hydrate composed of C 68 H 66 O 5 

 + 2 (HO). 



Stearates of silver and lead are composed as follows : 

 Stearate of silver, . C 68 H 66 O 5 + 2 (Ag O) 

 Stearate of lead, . C 68 H 66 O 5 + 2 (Pb O) 



The two atoms of the oxides of silver and lead taking the place 

 of the two atoms of water in the hydrated acid. 



Dr Redtenbacher also formed stearic ether, or, as it is now 

 called, stearate of oxide of ethyle, by dissolving stearic acid in 

 alcohol and passing a current of muriatic gas through the solu- 

 tion till it refused to absorb more. Its composition was 

 , 1 atom stearic acid, . C 68 H 66 O 5 = 64-25. 

 1 atom ether, . C 4 H 5 O = 4-625. 



1 atom water, . H O = 1-125. 



70 



Margaric acid was obtained by M. Redtenbacher and M. Var- 

 rentrapp by distilling stearic acid. Its constitution is C 34 H 33 

 O 3 = 32-625. 



Hydrated margaric acid is C 34 H 33 O 3 + HO = 33-75. 

 Margarate of silver is C 34 H 33 O 3 -f Ag O. The atom of oxide 

 of silver taking the place of the atom of water in the hydrate. 



* Annalen der Pharmacie, xxxv. 46, 65, and 86. 



