THE CONQUEST OF NATURE 



between energy expended and result achieved is highly 

 satisfactory from a business standpoint, and will doubt- 

 less become still more so as the apparatus is further 

 perfected. 



To the casual reader, unaccustomed to chemical 

 methods, there may seem a puzzle in the explanation 

 just outlined. He may be disposed to say, "You speak 

 of the nitrogen as being ignited and burned; but if 

 it is burned and thus consumed, how can it be of ser- 

 vice?" Such a thought is natural enough to one who 

 thinks of burning as applied to ordinary fuel, which 

 seems to disappear when it is burned. But, of course, 

 even the tyro in chemistry knows that the fuel has not 

 really disappeared except in a very crude visual sense; 

 it has merely changed its form. In the main its solid 

 substance has become gaseous, but every atom of it 

 is still just as real, if not quite so tangible, as before; 

 and the chemist could, under proper conditions, collect 

 and weigh and measure the transformed gases, and 

 even retransform them into solids. 



In the case of the atmospheric nitrogen, as in the case 

 of ordinary fuel, a burning "consists essentially in 

 the union of nitrogen atoms with atoms of oxygen." 

 The province of the electric current is to produce the 

 high temperature at which alone such union will take 

 place. The portion of nitrogen that has been thus 

 "burned" is still gaseous, but is no longer in the state 

 of pure nitrogen; its atoms are united with oxygen 

 atoms to form nitrous oxide gas. This gas, mixed 

 with the atmosphere in which it has been generated, may 

 now be passed through a reservoir of water, and the 



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