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'3 



FOOD FROM THE AIR 



of the German plants is not available. The ammonia produced may be con- 

 verted in any ammonium compound (the sulfate is very largely produced) 

 or oxidized into nitric acid. 



Gilbert regards the process as not having yet shown high practical value, 

 and as not likely to be extensively applicable in the United States. 



The production of nitric acid by the oxidation of ammonia deserves brief 

 notice. This takes place under the influence of a catalyst, the best being, so 

 far as known, smooth solid platinum. Certain specified conditions must be 

 maintained or a reaction liberating nitrogen will occur. The reaction desired 

 is NH3+ O4 — ^ HNO3+ H2O. Other catalysts have been discovered, among 

 which is a mixture of ceria and thoria, somewhat similar to that used in the 

 Welsbach mantle. This is cheaper than platinum, especially at the present 

 time, but is not so efficient. A German patent covers the use of a mixture of 

 roasted iron pyrites and copper oxid — which may possibly be obtained by 

 roasting the common copper pyrites — claiming that under this influence 

 nitrous anhydrid, N2O3, is formed readily from a mixture of ammonia and 

 oxygen. 



There is no question that the methods of increasing the supply of nitrogen 

 compounds, particularly the utilization of atmospheric nitrogen, are of the 

 greatest importance to civilized nations. The stress under which the entente 

 powers of western Europe, especially Great Britain, have been placed in con- 

 sequence of inability to secure within their own borders sufficient food and 

 explosives, thus forcing dependence upon sea-borne traffic, now most seriously 

 threatened by the submarines of the central powers, indicates the peril of all 

 nations that neglect to provide for abundant plant food. 



Gilbert (see bibliography), writing in the early part of 191 6, thus sum- 

 marizes the condition and prospects of the several methods. 



Nitrogenous compounds are essential not only for the manufacture of 

 explosives, but to maintain the country's capacity for self-support. To be 

 effective, the source must be such that the products may be adaptable to either 

 requirement. 



The arc method has not thus far demonstrated capacity to meet the agri- 

 cultural requirement at all or even the defense requirement efficiently. 



Definite knowledge concerning the Haber (synthetic ammonia) process is 

 lacking, but the record of achievement is against it and it would seem unsuited 

 to American conditions, at least in the present state of its development. 



