ON LIVE STOCK FOOD 



that in less than twenty years these beds -would be 

 exhausted. 



No one then could say just how the need of the 

 agriculturist would subsequently be met. 



But the discovery that leguminous plants 

 extract nitrogen from the air gave partial answer. 



And almost simultaneoulsy a "more complete 

 answer was supplied by scientific workers, headed 

 by the Swedish chemist, Professor Christian Birke- 

 land, in association with a practical engineer, Mr. 

 S. Eyde, who discovered that it is possible to con- 

 vert atmospheric nitrogen into nitric acid with 

 the aid of electricity. 



Another method of fixing atmospheric nitrogen 

 was soon afterward developed in Italy. Thus the 

 inexhaustible sources of the atmosphere were 

 made available. So there is no longer any danger 

 of a nitrogen famine, and the developer of plants 

 no less than the consumer of plant-products may 

 look forward without apprehension, so far as the 

 danger of the starvation of plants for lack of nitro- 

 gen is concerned. 



But the mechanical processes of nitrogen 

 fixation are necessarily expensive, and the aid of 

 the clovers and their allies will no doubt continue 

 to be sought for a long time to come by the agri- 

 culturist who wishes to restore nitrogen to his 

 fields in the most economical manner. 



[105] 



