306 AGRICULTURAL, ANALYSIS 



in all cases, a loss 01 nitrogen during the summer when the soils 

 were kept bare, and the losses were greatest where manure had 

 been used. 



These data show that the problem of increasing soil nitrogen 

 in a uniform manner through the oxidation of atmospheric nitro- 

 gen is still unsolved. There is probably no other one problem 

 of greater importance to agriculture. The nitrogenous fertilizers 

 are of dominant importance, both by reason of their high cost and 

 of the necessity of their presence in order that the other fertil- 

 izing materials in the soil shall be duly utilized. There are many 

 indications, however, that in the near future the method for the 

 utilization of atmospheric nitrogen by direct oxidation thereof 

 in the field, either with or without the aid of growing plants, 

 may be discovered and thus the farmer made more independent 

 of the nitrogen now stored in various parts of the earth or pro- 

 duced by manufacturing operations. 



268. Manufacture and Use of Cyanamid for Fertilizing Pur- 

 poses. Cyanamid has the general formula H 2 N : CN. With 

 univalent metals it yields metallic compounds corresponding to 

 M 2 N : CN. In investigating the manufacture of cyanids by 

 means of carbids, Frank and Caro observed that if moist atmos- 

 pheric nitrogen be passed through a retort heated to dull redness 

 and containing a mixture of calcium and barium carbids, the 

 nitrogen becomes fixed to the metal with formation of cyanid ; 

 besides cyanid, other nitrogenous compounds, e. g., cyanamid, 

 due in part to the action of the cyanid already formed and in 

 part to the direct action of the reacting mass, as the following 

 equations indicate, are formed: 69 



X(2MCN)+XN=X(M 2 NCN) + (CN)X 

 M 2 C 2 -fN 2 =M 2 NCN-fC 



The formation of cyanamid may be increased by giving the 

 carbid a large surface thus allowing a large amount of nitrogen to 

 act upon a small quantity of carbid. Frank and Caro's process 

 is based on this observation. 



The process of the Deutsche Gold und Silber Scheide Anstalt 



69 Robine and Lenglen, The Cyanid Industry, Translated by LeClerc, 

 1906, : 144. 



