262 
The carbon and hydrogene abounding in oily 
substances fully account for their effects ; and their 
durability is easily explained from the gradual man- 
ner 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 probably be repaid by the increase 
of their fertilizing powers ; 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 em- 
ployed 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 
decomposable substances in bone are fat, gelatine, 
and cartilage, which seems of the same nature as 
coagulated albumen. 
According to the analysis of Fourcroy and Vau- 
quelin, ox bones are composed 
Of decomposable animal matter - 51 
— phosphate of lime - - 37-7 
— carbonate of lime 10 
— phosphate of magnesia . - 1.3 
100 
