114 AGRICULTURAL CHEMISTRY 



oil, anthracene oil, and pitch or artificial asphaltum. The 

 naphtha or light oil consists of a mixture of hydrocar- 

 bons, benzine being among the number. Benzine is ex- 

 tensively used as a solvent for fatty bodies. It is a very 

 inflammable liquid. 



138. Aliphatic and Aromatic Series of Compounds. 

 In organic chemistry benzine occupies an important posi- 

 tion, as the direct treatment of benzine and its deriva- 

 tives, produces the aromatic series of compounds, which 

 form one of the two main divisions of the subject. The 

 other is obtained from methane and its derivatives, 

 and constitutes the aliphatic series. The alcohols, ethers, 

 glycerides, fatty acids, organic acids, carbohydrates, and 

 amids, are members of the aliphatic series, while essen- 

 tial oils, coloring-matters, and mixed nitrogenous com- 

 pounds, are members of the aromatic series. In or- 

 ganic chemistry, a study is made of the formation, 

 relationship, structure, and properties of all these com- 

 pounds. Hence the importance of this branch of chem- 

 istry. 



139. Carbon Disulfid. With sulfur, carbon forms car- 

 bon disulfid, CS 2 , a clear liquid with a characteristic odor. 

 It readily burns and is easily vaporized. It is a solvent 

 for fats, resins, sulfur, and iodin, and is used for the de- 

 struction of insects, particularly those infesting grains, 

 and for killing small burrowing animals, as gophers. 



140. Cyanids. In the presence of metals carbon unites 

 indirectly with nitrogen, forming cyanids as KCN. When 

 mercuric cyanid is heated, cyanogen gas and metallic 

 mercury are formed : Hg(CN) 2 = Hg -j- 2CN. Cyano- 



