BONE AS MANURE. 



While the Station has in the sixteen years of its existence 

 analyzed numerous samples of bone, its investigations have not 

 added greatly to the knowledge of the value of bones as fertilizer. 

 The Station is, however, in frequent receipt of inquiries relative 

 to the value of bone meal as a manure, and because of these 

 inquiries the following is written. 



Bones owe their fertilizing value to the nitrogen and the phos- 

 phoric acid, which they contain. If a bone is soaked for a long 

 time in dilute muriatic acid, the mineral portion is dissolved and 

 a tough pliable mass of the same shape of the original bone is 

 left. This is the organic matter of the bone, composed chiefly 

 of ossein, a nitrogenous material which by long boiling is 

 changed into glue or gelatine. This organic matter makes up 

 from one quarter to one third of the weight of the bone. If a 

 bone is thoroughly burned in fire the organic matter is destroyed 

 and there is left the bone ash. Bone ash is composed chiefly of 

 phosphate of lime, together with a little carbonate of lime and 

 phosphate of magnesia. Raw bone has, in addition to the min- 

 eral matter and the ossein, more or less of fats and oils and some 

 water. *■ 



When bone or bone ash is treated with strong sulphuric acid, 

 part of the lime is taken away from the bone phosphate of lime 

 and new compounds are found. One of these new compounds 

 is a phosphate of lime containing only one-third as much lime as 

 did the original bone phosphate. The rest of the lime unites 

 with the acid and makes gypsum or land plaster. In practice, 

 if sufficient acid were used to change all the bone phosphate into 

 acid phosphate, the resulting mass would be too pasty and 

 unmanageable for making fertilizers When less acid is added, 

 part of the bone phosphate is changed into the acid phosphate, 

 and part into still another compound which has two-thirds as 

 much lime as the original bone phosphate. The acid phosphate 



