136 



as such has long been recognized in Europe, 

 especially in England, where they have been greatly 

 instrumental in maintaining the high returns. 



Earthy Phosphates, being insoluble in pure 

 water, could not assist in the nourishment of 

 plants, were it not for their peculiar property of 

 becoming soluble in water containing carbonic 

 acid ; but even then their solubility is very 

 small (four thousand parts of water containing 

 carbonic acid dissolving only one part of finely- 

 divided Phosphates), and depends upon the fine- 

 ness of their division ; so that the finer the bones 

 are broken up, and the larger the percentage of 

 carbonic acid in the soil, the more rapid will be 

 the decomposition. 



A whole bone, or even coarse fragments, will 

 remain several years in the soil without their 

 volume being reduced to any appreciable degree. 

 The organic substances will, of ^course, be decom- 

 posed, but they will be distributed over the field 

 before the carbonic acid, the result of their decay, 

 can exert any great solvent action upon the bones, 

 the contact surface of which is not very great. 



But if bones are finely pulverized, they not only 

 permit a much more uniform distribution over the 

 field, but the contact surface is so great every 

 particle of the powder being exposed to the solvent 

 action of carbonic acid and moisture that even in 

 the first year of application the plant receives the 



