TECHNICAL CHEMISTRY. 439 



carbon monoxide. Eobert Bimsen long ago showed that by using 

 steam the nitrogen in an 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 medium of a catalyzing or con- 

 tact agent, the production of nitrates by way of the cyanide reaction 

 is easily foreseen. 



The Siemens and Halske Company prepared in addition to cyanide 

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

 in technical chemistry, calcium cyanamide. In contradistinction to 

 cyanides the nitrogen of this compound is available for plant food 

 and can take the place of the more common nitrogen salts in com- 

 mercial 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 Atmos- 

 pheric Products Company, operating at Xiagara Falls. For agricul- 

 tural 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 present 

 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 U. S. Department of Agriculture, with the result that cultures for 

 the artificial inoculation of the soil may now be obtained in consider- 

 able quantity. It has been found that these bacteria when grown 

 upon nitrogen-free media may be dried without losing their high 

 activity. Wlien immersed in water they are easily revived. A dry 

 culture similar to a yeast-cake and of about the same size can thus be 

 sent out and used to prepare a fluid in which the original nitrogen 

 fixing bacteria may be multiplied sufficiently to inoculate a number of 

 acres of land. The amount of material thus obtained is limited only 

 by the quantity of the nutrient water solution used in increasing the 



