TRADE VALUE OF FERTILIZERS 345 



fertilizers. These values are based on the cost of the 

 unmixed constituents, if purchased in wholesale lots 

 from the manufacturer, and are secured by averaging 

 the wholesale prices per ton of all the various fertilizer 

 supplies for the six months preceding March 1, to which 

 is added about 20 per cent of the price, to cover cost of 

 handling. The trade values for 1907 were as follows: 



Value per pound 

 Cents 

 Nitrogen, in nitrates 18.5 



Nitrogen, in ammonium salts 17.5 



Organic nitrogen, in dried and finely ground fish meat 



and blood, and in mixed fertilizers 20.5 



Organic nitrogen, in finely ground bone and tankage. .20.5 

 Organic nitrogen, in coarsely ground bone and tankage. 15.0 



Phosphoric acid, soluble in water 5.0 



Phosphoric acid, soluble in ammonium citrate 4.5 



Phosphoric acid, insoluble, in fine bone and tankage. . 4.0 

 Phosphoric acid, insoluble, in coarse bone and tankage . 3.0 



Phosphoric acid, insoluble, in mixed fertilizers 2.0 



Phosphoric acid, insoluble, in finely ground fish, cotton- 

 seed meal, castor pomace and wood-ashes 4.0 



Potash, as muriate 4.5 



Potash, as sulfate, and in forms free from muriates. . 5.0 



213. Computation of the commercial value of a ferti- 

 lizer. The percentage of each fertilizing constituent of a 

 fertilizer, and its form or rate of solubility being known, it 

 is possible to calculate its commercial value. Suppose a 

 fertilizer costing $48 per ton contains the following: 



Per cent 

 Nitrogen in sodium nitrate 4 



Nitrogen in fine bone 3 



Phosphoric acid, available, in rock superphosphate 



(corresponds to soluble in ammonium citrate) .... 6 



Phosphoric acid, insoluble, in fine bone 22 



Potash, water soluble, in muriate of potash 10 



