690 TECHNICAL CHEMISTRY 



of this reaction may be mentioned the Ampere Chemical Company 

 located at Niagara Falls, and the group of men represented by the 

 Siemens-Halske Company of Berlin. The former first produces a 

 carbide of barium and then converts it into barium-cyanide by pass- 

 ing over it air from which the oxygen has either been removed or 

 converted into carbon monoxide. Robert Bunsen long ago showed 

 that by using steam the nitrogen in all alkaline cyanide may be 

 converted into ammonia. In this case barium oxide would be left 

 to be returned to the furnace, and to continue the cycle. When 

 advantage is taken of the process discovered by Professor Ostwald, 

 by which ammonia is converted into nitric acid through the me- 

 dium of a catalyzing or contact agent, the production of nitrates 

 by way of the cyanide reaction is easily foreseen. 



The Siemens-Halske Company prepared, in addition to cyanide 

 and ammonia, by use of the carbide-nitrogen reaction, a new com- 

 pound in technical chemistry, calcium cyanamide. In contradis- 

 tinction to the cyanides the nitrogen of this compound is available 

 for plant-food and can take the place of the more common nitrogen 

 salts in commercial fertilizers. The technical difficulties in the 

 way of the economic application of these processes are doubtless 

 very great, but when one considers the advance which has been 

 made in the last five years he has ample reasons to believe that it 

 will not be a great while before the synthetic preparation of the 

 cyanides, ammonia, and nitric acid from atmospheric nitrogen 

 will be on a commercial basis. 



The old reaction by which nitrogen and oxygen were made to 

 unite through the agency of a high potential electric discharge has 

 been made the basis of a process for the manufacture of nitric acid 

 by the Atmospheric Products Company, operating at Niagara Falls. 

 For agricultural purposes it is proposed to absorb the nitric acid 

 thus formed in milk of lime, and so produce an exceptionally cheap 

 product. There still remains much to be done before this can be 

 called a technical process. 



A very much less technical, but, so far as our knowledge at pre- 

 sent goes, a more promising method of fixing atmospheric nitrogen 

 in the form of nitrates is through the agency of bacteria. While it 

 is true that one group of bacteria has the power .of breaking down 

 nitrates with the production of nitrogen gas, there are other groups 

 which are equally able to absorb elementary nitrogen with the 

 production of nitrates. A great deal of excellent work has recently 

 been done by the United States Department of Agriculture with 

 the result that cultures for the artificial inoculation of the soil may 

 now be obtained in considerable quantity. It has been found that 

 these bacteria when grown upon nitrogen free media may be 

 dried without losing their high activity. When immersed in water 



