39 



into an evaporator and allowed to stand in the cold until all free 

 ammonia had evaporated. The solution was reserved for further 

 investigation. 



The insoluble portion was subjected to a combustion analy- 

 sis. The ' 'nitrogen as ammonia" represents the amount of 

 nitrogen expelled by boiling with magnesia. 



Carbon 



Hydrogen 



Oxygen 



Nitrogen (total) 



Nitrogen (as ammonia) 



62.29% 



5- 

 28.1 



3-25 



Although humus varies in its content of nitrogen (depend- 

 ing on the material from which it is formed) the above agrees 

 fairly well with the average analysis of humus extracted from 

 soil by various solvents. Regarding the form in which nitrogen 

 is held in this compound, Berthelot has shown that besides 

 ammonia, it is present most probably as amide. This fact is in 

 accordance with the data obtained when working with the nat- 

 ural product. 



The action of this substance on superphosphate was investi- 

 gated. The material was treated with a solution of superphos- 

 phote in the manner already described for humic acid. The 

 solution contained, 



P 2 O 5 o. 1550 grs. 



Ca <- 0.0185 S rs - 



The quantities of phosphoric acid remaining unabsorbed by 

 i gram of the insoluble ammonium humate are given below. 



No. 



i 



2 



3 

 4 

 5 

 6 



Duration of contact. 



one day 



one day 



four days 



four days 



eight days 



eight days 



P 2 O 5 soluble. 

 0.1540 grs. 



0.1545 g r s. 

 o.i 540 grs. 

 o. 1540 grs. 

 o.i 540 grs. 

 o. 1540 grs. 



Ca soluble. 

 0.0185 grs. 

 0.0178 grs. 

 0.0191 grs. 

 0.0183 grs. 

 0.0178 grs. 

 0.0187 grs. 



The results show that the insoluble ammonium humate ex- 

 erted no influence in retaining the phosphoric acid of superphos- 

 phate. The content in calcium was also not affected. 



