The organic nitrogeu in suj^erphosphates, special manures and 

 fertilizers of a high grade is usually valued at the highest fig- 

 ures laid down in the trade values of fertilizing ingredients in raw 

 materials, namely, 19 cents per pound ; it being assumed that the or- 

 ganic 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. For similar reason the 

 insoluble phosphoric acid is valued in this connection at three cents, 

 it being assumed, unless found otherwise, that it is from bone, or 

 similar source and not from rock phosphate. In this latter form 

 the insoluble phosphoric acid is worth but two cents per pound. 



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

 preceding March, 1889, the respective ingredients could be bought at 

 retail for cash m 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 1st, plus about 20 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 composition of the refuse. To assist the farm- 

 ing community in a clear and intelligent appreciation of the various 

 substances sold for manurial purposes, a frequent examination into 

 the temporary characters of agricultural chemicals and }efuse mate- 

 rials 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 buy when- 

 ever practicable, on guarantee of composition with reference to their 

 essential constiteunts ; and to see to it that the bill of sale recognizes 

 that point of the bargain. Any mistake or misunderstanding in the 



