296 IMPROVEMENT OF THE SOIL 



4. Wool contains, in 100 parts, 



Oxygen and sulphur 24.608 



100.000 



5. Feathers are composed, in 100 parts, of 



Carbon 52.427 I Nitrogen 17.893 



Hydrogen 7.213 | Oxygen 22.467 



Wool, woollen rags, and the refuse from woollen manufactories, 

 hair and feathers, contain an oil in addition to their protein, 

 which increases their value, and renders them excellent ma- 

 nures. The washings from the wool annually consumed in 

 France, would yield sufficient manure for 370,000 acres of 

 land. This wool-sweat is an excellent manure. 



G. Glue, jelly, etc. is derived from cartilage, skin, bone 

 and tendon, by boiling them in water ; but it is not found in 

 healthy animals. It constitutes a powerful manure. 



7. Bones are composed of animal matter, phosphate of 



lime and of magnesia, and carbonate of lime: 100 parts of 



the bones of the ox, as analyzed by Davy, yielded, of 



Decomposable anini. matter .51 j Carbonate of lime 10. 



Phosphate of lime 37. ' Phosphate of magnesia 1.3 



The value of bones depends upon their power of producing 

 ammonia and salts. For the former purpose, they are at 

 least 8 or 10 times as valuable as cow dung, and the quantity 

 of salts is 66 times that contained in an equal quantity of that 

 substance. They constitute, then, a most concentrated ani- 

 mal manure, and have been long used by the most intelligent 

 farmers for improving their soils. For this purpose they are 

 crushed in a mill, made for the purpose, and constitute 

 Bone dust. The value of this manure may be estimated 

 by the quantity which is imported into England, amounting 

 animally to 800,000 dollars worth. It is estimated that this 

 adds to the agricultural products more than 16 million 

 bushels of grain.. Bone dust is now used in this country to a 

 considerable extent. One bushel to a load of yard manure, 

 increases its value, as determined by experiment, one half. 



