The carbon and hydrogen abounding in oily substances fully account for their effects; and their durability is 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 neighbourhood 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 employed 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 decomposed substances in bone are fat, gelatine and cartilage, which seems of the same nature as coagulated albumen.
According to the analysis of Fourcroy and Vauquelin ox bones are composed
| Of decomposable animal matter, | 51 |
| phosphate of lime, | 37.7 |
| carbonate of lime, | 10 |
| phosphate of magnesia, | 1.3 |
| 100. |
M. Merat Guillot has given the following estimate of the composition of the bones of different animals.
| Phosphate of lime. | Carbonate of lime. | ||
| Bone of | Calf, | 54 | |
| Horse, | 67.5 | 1.25 | |
| Sheep, | 70 | 5 | |
| Elk, | 90 | 1 | |
| Hog, | 52 | 1 | |
| Hare, | 85 | 1 | |
| Pullet, | 72 | 1.5 | |
| Pike, | 64 | 1 | |
| Carp, | 45 | 5 | |
| Horses' | Teeth, | 85.5 | 25 |
| Ivory, | " | 64 | 1 |
| Hartshorn, | 27 | 1 | |
The remaining parts of the 100 must be considered as decomposable animal matter.