COMMERCIAL FERTILIZERS 203 



organic forms of potash. Substances like feldspar, 

 which contain insoluble potash, are of no value in fer- 

 tilizers. As a rule, the potash in commercial ferti- 

 lizers is soluble in water ; in only a few cases are acid- 

 soluble forms met with. Insoluble potash would be 

 considered an adulterant. 



275. Misleading Statements on Fertilizer Pack- 

 ages. Occasionally the percentage amounts of nitro- 

 gen, phosphoric acid, and potash are stated in mis- 

 leading ways ; as ammonia, sulphate of potash, and 

 bone phosphate of lime. Inasmuch as ammonia con- 

 tains 14 parts nitrogen and three parts by weight of 

 hydrogen, it follows that the ammonia content is pro- 

 portionally greater than the nitrogen content, be- 

 cause of the additional hydrogen carried by the ammo- 

 nia. And so with sulphate of potash which contains 

 about 50 per cent, potash and 50 per cent, of sulphuric 

 anhydrid. This method of stating the composition 

 can be considered in no other way than as a fraud, 

 especially when the fertilizer contains no sulphate of 

 potash, but cheaper materials, and the phosphoric acid 

 is not derived from bone. 



276. Estimated Commercial Value of Fertilizers. 

 The estimated value of a commercial fertilizer is 

 obtained from the percentage composition and the 

 trade value of the materials used. Suppose that two 

 fertilizers are selling at $25 and $30, respectively, 

 each having a different composition, the estimated 

 values of each would be obtained in the following 

 way : 



