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durability is easily explained from the gradual manner 

 in which they change by the action of air and water. 



Bones are much used as a manure in the neigh- 

 bourhood of London. After being broken and boiled 

 for grease, they are sold to the farmer. The more 

 divided they are, the more powerful are their effects. 

 The expense of grinding them in a mill would proba- 

 bly be repaid by the increase of their fertilizing pow- 

 ers ; and in the state of powder they might be used in 

 the drill husbandry, and delivered with the seed in the 

 same manner as rape cake. 



Bone dust, and bone shavings, the refuse of the 

 turning manufacture, may be advantageously employ- 

 ed in the same way. 



The basis of bone is constituted by earthy salts, 

 principally phosphate of lime, with some carbonate of 

 lime and phosphate of magnesia ; the easily decom- 

 posable substances in bone are fat, gelatine, and cartil- 

 age, which seems of the same nature as coagulated 

 albumen. 



According to the analysis of Fourcroy and Van- 

 quelin, ox bones are composed 



Of decomposable animal matter 51 



phosphate of lime - 37.7 



carbonate of lime - 1O 



phosphate of magnesia - 1.3 



100 



M. Herat Guillot has given the following esti- 

 mate of the composition of the bones of different 

 animals. 



