WOMEN AS INVENTORS 353 



solution, and never did science more quickly and effica- 

 ciously respond. It was soon recognized that the earth's 

 atmosphere was the only available storehouse for the much- 

 needed nitrogen. Forthwith scientists and inventors the 

 world over proceeded to tap this source of supply and to 

 convert its vast stores of nitrogen into the nitrates which 

 are so indispensable to vegetable life. 



To form some idea of the importance of the problem and 

 the urgency of its solution, it may be stated that the 

 amount of fertilizer required for the cotton crop alone in 

 the Southern States in 1911 was no less than three million 

 tons. What, then, must have been the total amount used 

 through the world for cereals and other crops that need 

 constant fertilizing? The famous nitrate deposits of Chili 

 could supply only a small fraction of the stupendous 

 amount required, and they, according to recent calcula- 

 tions, cannot continue to meet the present demands on them 

 for more than a hundred years longer, at most. 



The process involved, when once conceived, was simple 

 enough, for it merely required the conversion of the nitro- 

 gen of the air into nitric acid, which in turn was employed 

 in the production of nitrate of lime. But, simple as it was, 

 mankind had to wait a long time for its origination, and 

 action was taken only when necessity compelled. At pres- 

 ent there are numerous nitrate factories in France, Ger- 

 many, Austria, Sweden, Norway and the United States, 

 and the output is already enormous and constantly increas- 

 ing. Electricity, that mysterious force which has so fre- 

 quently come to man's assistance during the last few 

 decades, is the agent employed. 



But who was the originator of the idea of utilizing the 

 atmosphere for the production of nitrates? Who took out 

 the first patent for a process for making nitrates by using 

 the nitrogen of the air? It was a Frenchwoman Mme. 

 Lefebre, of Paris long since forgotten. As early as 1859 

 she obtained a patent in England for her invention, but, 



