CYANAMID — manufacture:, CHEMISTRY AND USES 45 



equivalent to the amount of cyanamide used. Each flask was 

 equipped with connections permitting a current of air to pass 

 through the flask, and then through a bottle of dilute sulphuric 

 acid to catch any ammonia evolved in the flask. The balloon 

 flasks were held in a thermostat at 25° for 22 days, at the end 

 of which time 800 cc. water was added. After shaking and 

 standing an hour and filtering with suction, tests showed that 

 there was no cyanamide or dicyandiamide present in the flask 

 to which cyanamide had been added. Determinations were 

 made for total nitrogen, ammoniacal nitrogen and nitric nitro- 

 gen in the solution. 



The following values were obtained: 



Soil plus 

 Soil plus ammonium 



cyanamide carbonate 



mg. mg. 



Initial nitrogen 560 560 



Final nitrogen absorbed by soil. 450 420 



Final nitrogen remaining in solution : 



Ammoniacal 60 70 



Nitrate 9 70 



Cyanamide o — 



Dicyandiamide o — 



Undetermined 41 o 



The sulphuric acid in the bottles, through which bubbled the 

 air leaving the flasks, was unchanged, hence, no ammonia 

 escaped from the soil. 



Since the 41 mg. of undetermined nitrogen in the solution 

 from the cyanamide flask was not cyanamide, dicyandiamide, 

 ammonia or nitrate nitrogen, it must have been urea, in accord- 

 ance with the previous experiment. The conversion of the 

 urea to ammonium salts was therefore not quite complete. The 

 conversion of ammonium salts to nitrates was also less than 

 the conversion in the case of ammonium carbonate. The 

 amount of ammoniacal nitrogen in solution is practically equal 

 in the two flasks. It is evident, therefore, that in both cases 

 the absorbed nitrogefl exists in the soil in the state of am- 

 monium salts, and these are in equilibrium with the ammonium 

 salts in the solution. Since the soil was not sterilized and low 



