COTTON CULTURE 7 I 



stance commonly called gelatine. It is distributed through- 

 out the entire mass of bone, and is rich in nitrogen. When 

 bones are burned, the nitrogenous matter is driven off 

 and only the mineral portion of phosphate of lime remains. 

 Bones, such as are used in making commercial fertilizers, 

 contain four to five per cent of nitrogen and from twenty 

 to twenty-five per cent of phosphoric acid. About two- 

 thirds of the latter is insoluble and approximately one- 

 third available. 



Bone Products are valuable fertilizers, as they supply 

 phosphoric acid, and generally nitrogen also. The most 

 common forms are bone-black, bone meal, and bone tankage. 

 Bone-black is a by-product of sugar refining, and contains 

 from thirty to thirty-five per cent insoluble phosphoric 

 acid. Dissolved bone-black contains sixteen to seventeen 

 per cent available phosphoric acid. Bone meal is simply 

 ground bones, steamed or raw. It contains two and one- 

 half to five per cent of nitrogen and twenty to twenty- five 

 per cent of phosphoric acid. Bone tankage is a very irreg- 

 ular product, but follows bone meal closely in composition. 

 It is a by-product of the smaller packing houses. 



Phosphate Rock is a mineral phosphate, found in 

 various States. In a raw condition it contains from 

 twenty-five to thirty-five per cent phosphoric acid, all of 

 which is insoluble and not available for plant food. The 

 mineral has to be treated with sulfuric acid, before the 

 phosphoric acid can be liberated. 



Acid Phosphates are known under several different 

 names, such as superphosphates, dissolved bone, dissolved 



