254 AGRICULTURAL EXPERIMENT STATION. [Jan. 



The organic nitrogen in swperpliosphales , .y)ecial manures 

 and mixed fertilizers of a high grade is usually valued at the 

 hisfhest fisrures laid down in the trade values of fertilizino 

 ingredients in raw materials, namely, fifteen and a half cents 

 per pound ; it being assumed that the organic nitrogen is 

 derived from the best sources, viz., animal matter, as meat, 

 blood, bones, or other equally good forms, and not from 

 leather, shoddy, hair, or any low-priced, inferior form of 

 vegetable matter, unless the contrary is ascertained. The 

 insoluble phosphoric acid is valued in this connection at two 

 cents. 



The above trade values are the figures at which, in the six 

 months preceding March, 1891, the respective ingredients 

 could be bought at retail for cash in our large markets, in 

 the raw materials, which are the regular source of supply. 



They also correspond to the average wholesale prices for 

 the six months ending March 1, plus about twenty per cent, 

 in case of goods for which we have wholesale quotations. 

 The valuations obtained by use of the above figures will be 

 found to agree fairly with the retail price at the large markets 

 of standard raw materials, such as : — 



Sulphate of ammonia, Dry ground fish, 



Nitrate of soda, Azotin, 



Muriate of potash. Ammonite, 



Sulphate of potash, Castor pomace. 



Dried blood, Bone and tankage. 



Dried ground meat. Plain superphosphates. 



A large percentage of commercial materials consists of 

 refuse matter from various industries. The composition of 

 these substances depends on the mode of manufacture carried 

 on. The rapid progress in our manufacturing industries is 

 liable to affect at any time, more or less seriously, the com- 

 position of the refuse. To assist the farming community in 

 a clear and intelligent appreciation of the various substances 

 sold for manurial purposes, a fi'equent examination into the 

 temporary characters of agricultural chemicals and refuse 

 materials offered in our markets for manurial purposes is 

 constantly carried on at the laboratory of the station. 



Consumers of commercial manurial substances do well to 



