32 MAINE STATE COLLEGE 



The degree of solubility for cheap and inferior ''■amraoaiates" 

 such as horn, hoof, leather and wool waste is seen to vary from 

 4.8 per cent, to 37.8 per cent., while in the case of dried blood, 

 cotton-seed meal, dried and ground flesh, dried fish, fish scrap and 

 ground bone the average percentages of the different trials range 

 from 70.9 per cent, to 97.3 per cent. 



It is shown by the Conn. Experiment Station* that mixing with 

 these arrimoniates mineral compounds of the kind and in the 

 quantity that would be found accompanying them in superphos- 

 phates does not materially chauge their solubility in a pepsin 

 solution, consequently it is fair to conclude that the solubility in a 

 pepsin solution of the organic nitrogen of a superphosphate will 

 show whether this ingredient is furnished largely in an inferior 

 form. 



In accordance with this idea, Mr. Merrill has tested the solubility 

 of the organic nitrogen in the superphosphates inspected by this 

 Station for 1889. 



His methods were as follows : 



The sample taken to represent a brand of superphosphate was 

 made up so as to represent the average of all the samples of that 

 brand selected this season. This was done, for instance in the 

 case of the Bay State Fertilizer by weighing out equal quantities 

 of Nos. 412, 418 and 428, and thoroughly mixing them in a mortar. 

 One gram of substance was thoroughly leached with water and 

 then submitted to the action of a pepsin solution in accordance 

 with the method previously given. The insoluble nitrogen of the 

 residue was then determined. 



The percentages of organic nitrogen given are the total nitrogen 

 minus the nitrogen as nitric acid and ammonia. The tables 

 which follow explain themselves. 



* Report Cnnii. Hxperimenl Station, 18S5, pp. 120-121. 



