154 MANURES. 



Tea bushels of bones, finely ground, will produce 

 larger results, during the ten years after application^ 

 than would one hundred bushels merely broken ; not 

 because the dust contains more fertilizing matter than 

 the whole bones, but because that which it does con- 

 tain is in a much more available condition. It fer- 

 ments readily, and produces ammonia, while the 

 ashy parts ai-e exposed to the action of roots. 



It is a rule which is applicable to all manures, that 

 the more finel}^ they are pulverized or divided, the 

 more valuable they become. Not only do they ex- 

 pose much more surface to the feeding action of 

 roots, but from their fine division they can be much 

 more evenly distributed through the soil. If it is 

 true, as seems probable, tliat the absorptive power 

 of fertile soils is so strong as to prevent dissolved 

 plant food from being carried beyond the point with 

 which it first comes in contact, uutil the soil about 

 that point has taken up all that it is capable of hold- 

 ing, then the more widely we spread a manure before 

 it is dissolved, the more uniformly rich will be the 

 soil. By sowing coarsely crushed bones, we fertilize 

 the soil ill spots. By crushing each lump we not 

 only make all of its constituents immediately availa- 

 ble, but we make it reach every part of the surface 

 between the spots above referred to. Even Peruvian 

 guano, soluble as it is in water, is much more efiee- 

 tive when finely ground before being spread upon 

 the land. 



Bone-hlach. If bones arc burned in retorts, or 

 otherwise protected fr^m the atmosphere, their or 



