184 Fertilizers 



in mixed fertilizers, not because all insoluble costs the 

 price given, but because in mixtures it is assumed that the 

 phosphoric acid is drawn from organic sources, which do 

 cost, at least, the price given. 



There are arguments both in favor of and in oppo- 

 sition to this method of comparing the commercial values 

 of mixed fertilizers. The chief arguments in opposition 

 may be stated as follows : 



First, that the prices of these materials vary, and 

 hence in order to represent the actual commercial value 

 at the time the sales are made, they should be changed 

 as the markets change. 



Second, the valuations are misleading, because the 

 farmer does not clearly understand their meaning, and 

 is thus guided in his judgment of the usefulness or agri- 

 cultural value of a fertilizer by the stated commercial 

 value, as shown by this method, rather than by the kind, 

 form and proportion of constituents that may be contained 

 in it, and upon which its agricultural value should be 

 based. 



Third, the chemical analysis does not show absolutely 

 the sources of the materials, and thus it is difficult to place 

 a true commercial value upon a mixture. This is espe- 

 cially true of organic nitrogen, since because it is impos- 

 sible to separate the amounts that may be derived from 

 different materials, a uniform value is placed upon the 

 total nitrogen found, whether it is derived from the best 

 forms, as dried blood and dried meat, or whether derived 

 from horn meal, ground leather or other low-grade forms 

 of nitrogenous material. This encourages the use of low- 

 grade products by unscrupulous manufacturers, to the real 

 detriment of the trade as a whole. 



Fourth, that the commercial value so fixed militates 



