THE CONQUEST OF NATURE 



lies in the fact that the extremely high temperature 

 required about 4500 Fahrenheit can be obtained 

 economically in the electric furnace, but not otherwise. 

 Thus electricity created its own greatest rival as an 

 illuminant. It followed naturally that the ideal place 

 for manufacturing the carbide would be at the source 

 of the cheapest supply of electricity, and as the " har- 

 nessed" Niagara Falls represented the cheapest source 

 of electric supply, this place soon became the centre of 

 the carbide industry. Here the process of manufacture is 

 carried out on an enormous scale. In practice, lime 

 and ground coke are thoroughly mixed in the propor- 

 tion of about fifty-six parts of lime to thirty-six parts 

 of coke. When this mixture has been subjected to the 

 heat of the electric furnace for a short time an ingot of 

 pure calcium carbide is formed, surrounded by a crust 

 of less pure material. The ingot and crust together 

 represent sixty-four parts of the original ninety-two 

 parts of lime and coke, the remaining twenty-eight 

 parts being liberated as carbon-monoxide gas. 



Calcium carbide as produced by this process is a 

 dark-brown crystalline substance which may be heated 

 to redness without danger or change. It will not burn 

 except when heated in oxygen, and will keep indefinitely 

 if sealed from the air. Chemically it consists of one 

 atom of lime combined with two atoms of carbon 

 (CaC 2 ) ; and to produce acetylene gas, which is a com- 

 bination of carbon and hydrogen (C 2 H 2 ) it is only neces- 

 sary to bring it into contact with water, acetylene gas 

 and slaked lime being formed. One pound of pure 

 carbide will produce five and one half cubic feet of gas 



