PHOSPHO-NITROOENOUS MANUEES 



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that ingredient, but no nitrogen. It is more readily 

 soluble, and has, therefore, a higher agricultural value 

 than mineral phosphates containing the same percentage 

 of phosphoric acid, but since the introduction of basic 

 slag, it has been but little used as manure. 



Bone Char. Bone char or bone black consists practi- 

 cally of bone ash plus about 10 per cent, of carbon.. 

 When spent, it may be used as a phosphatic manure, 

 but is generally converted into bone ash. 



Typical analyses of the various bone products men- 

 tioned above are given in the following table: 



ANALYSES OF BONE PRODUCTS. 

 PER CENT. 



Dissolved or Vitriolated Bones. Dissolved bones bear 

 much the same relation to the raw bones from which 

 they are prepared, as superphosphate bears to the raw 

 native phosphates. The latter are often called mineral 

 superphosphates to distinguish them from the organic, 



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