Chemical Analyses of Fertilizers 183 



It will be observed that the schedule gives the cost 

 a pound of the different forms of nitrogen, and of high- 

 grade organic nitrogenous materials; of nitrogen and 

 phosphoric acid in ground bone and tankage ; of available 

 phosphoric acid in superphosphates, and of actual potash 

 in the potash salts, and is a useful guide also in showing 

 that the nitrogen, phosphoric acid and potash contained 

 in these materials can be purchased in ton lots for the prices 

 mentioned. The valuations of mixed fertilizers, obtained 

 by the use of this schedule, are entirely commercial ; they 

 are not intended to indicate even a possible agricultural value. 

 This point needs to be emphasized, as many are inclined 

 to interpret them as not only guides as to agricultural 

 value, but as positive statements of such value. It can 

 be said, however, that those who do so do not familiarize 

 themselves with the discussions that usually accompany 

 reports of analyses. The different trade values given for 

 the nitrogen and phosphoric acid in the two grades of bone 

 represent their value in the form of ground bone and of 

 bone meal, products which are distinctly recognized in 

 the market, and which are quoted at different prices. 

 The coarser ground bone is lower in price than the finer 

 bone meal. 



The accuracy of the schedule of values can be shown 

 by comparing it with the actual prices paid for the con- 

 stituents in the different materials, and such comparisons 

 as have been made from year to year, by a number of the 

 institutions exercising an analysis control, show that 

 manufacturers and dealers are willing to sell to farmers 

 at prices corresponding very closely with the schedule. 1 



A value is placed upon the insoluble phosphoric acid 



1 See Bulletins Connecticut and New Jersey Experiment 

 Stations. 



