PROPERTIES OF NITROGEN. 113 



carbon, hydrogen, oxj^gen, sulphur and phosphorus, it con- 

 stitutes, as so called, nitrogenous matter, a prominent part of 

 every vegetable and animal organ. 



Nitrogen in its free or uncombined state is a permanent gas, 

 somewhat lighter than air (-0.972 spec. grav. — Dumas) ; it 

 has no odor, no color, no taste ; and is most remarkable on 

 account of its chemical indifference towards other elements. 



All its combinations are produced, as a general rule, by 

 more or less circumstantial modes of operation ; they are all 

 more or less characterized by a certain degree of instability, 

 and are thus in an unusual degree liable to decomposition. 



Nitrogen does not directly unite with oxygen or Iwdrogen 

 or carbon or sulphur or phosphorus, the very elements which 

 constitute the entire organic portion of plants and animals. 



To combine it with oxygen requires the assistance of the 

 electric spark, or some other powerful physical or chemical 

 agent, which excites electrical changes. Evaporation, con- 

 densation and combustion are known to produce the chemical 

 combination of the oxygen and the nitrogen of the air to 

 nitrous and nitric acid. 



The same condition applies with still greater force to the 

 behavior of nitrogen towards hydrogen, in the formation of 

 ammonia. 



Nitrogen and hydrogen unite to form ammonia only then, 

 when they meet just emanating from decomposing compounds ; 

 and are consequently still in a peculiarly excited electrical 

 condition. 



To combine, chemically, carbon with nitrogen requires an 

 intense heat, and the presence of strong basic elements, like 

 potassium and sodium. 



An economical way to force the nitrogen into a chemical 

 combination wnth either oxygen, hydrogen or carbon, has 

 still to be discovered : past attempts in that direction have 

 thus far been but partly encouraging. The successful solution 

 of that problem will eventually affect the agricultural in- 

 dustry far more than at first glance might be presumed : it 

 would secure, if nothing else, for fertilizing purposes, the 

 entire amount of animal refuse material which serves for the 

 production of ammonia needed for other industrial purposes. 



Among the preceding remarks, there are two to which I 



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