206 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1923 



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Prior to the increased use of fertilizer in these countries, the pro- 

 ductivity of their soil was similar to our own, and the increase in 

 their food supply, without additional labor and at a cost wholly in- 

 commensurate with the gains, has grown in direct proportion to the 

 amount of fertilizer used. 



Besides fertilizers, large amounts of nitrogen are also needed for 

 industrial purposes, and the requirements to meet this demand are 

 also steadily increasing. 



Nitrate is one of the main ingredients in high explosives and gun 

 poAvder, and nitration, that is, the treatment of substances with nitric 

 acid, is the fundamental chemical operation in the production of 

 gun cotton for making smokeless powder, celluloid, or other pyroxylin 

 plastics from cotton or paper such as artificial ivory, etc. The dye 

 industry is also to a great extent based on nitration, and numerous 

 drugs, perfumes, and flavoring extracts are also being made in this 

 manner from the coal tar bases, benzol, toluol, and naphthalene. 



It is difficult to predict with accuracy to what extent the nitrogen 

 fixation in this country will increase in the future. From statistics 

 presented at a hearing before Congress in 1920, it was estimated that 

 the possible consumption of fixed inorganic nitrogen would be as 

 follows : • 



Agriculture . 

 Industries... 



Total. 



Tons 

 190, 000 

 130, 000 



320,000 



Tons 

 290, 000 

 150, 000 



440, 000 



To supply this need, it is further estimated that the available 

 production from by-product coke ovens will be, in 1925, 130,000 

 tons ; in 1930, 160,000 tons. 



The difference would then have to be supplied by importation of 

 Chile saltpeter or by increased products from atmospheric nitrogen 

 fixation plants. For this latter purpose, there are now three plants 

 in this country which with certain modifications would be available 

 and with a combined yearly production capacity equivalent to about 

 45,000 tons of fixed nitrogen per year. At present only one of these 

 plants is in operation, with a yearly output of only a few thousand 

 tons. 



From these figures, it is obvious that we will have to continue to 

 rely to a great extent on the importation of Chile saltpeter, unless 

 steps are taken for providing increased facilities for fixation of 

 atmospheric nitrogen. It is the purpose of this article to describe 

 the different processes which at present are available for this pur- 



