232 Wature'0 



relieved through the consumption of the gas 

 at the burners it allows the carbide to drop 

 into the water, when the evolution of the gas 

 begins again. 



Of course there is the same objection to this 

 mode of lighting that attends all open burners ; 

 it is constantly discharging into the air the 

 products of combustion, chiefly carbon dioxide, 

 which is poisonous to animal life. As has 

 been explained in some of the chapters on 

 heat, in Volume II, tin- illuminating property 

 of any gas is determined by the number of 

 carbon particles that are contained in it, which 

 become heated to incandescence as soon as 

 they come in contact with the oxygen of the 

 air, and remain so, for a brief period, during 

 their passage between the two extremes of the 

 flame. While acetylene equals electricity in 

 its illuminating properties, the latter still 

 stands without a rival when considered from 

 a sanitary standpoint, as the use of electricity 

 !(< not in any degree vitiate the air in a room 

 where it is used. 



We have now given somewhat in detail the 

 following processes that are carried on at 

 Xijigara Falls through the agency of elec- 

 tricity, viz. : The reduction of aluminum from 

 its oxide alumina; the production of the new 

 and useful compound called carborundum; 

 the formation of calcium carbide used for the 

 production of acetylene gas, and a large chem- 



