176 AMERICAN MANURES. 



plying them ; but to render them more im- 

 mediately available as food for plants, they 

 should be thoroughly incorporated with the 

 compost pile, as will be shown; 100 Ibs. of the 

 varieties of wood and coal ashes given, contain 

 the following amounts of potash and phosphoric 

 acid, with its value for agricultural purposes 

 annexed, estimating the phosphoric acid as in- 

 soluble, at 4i cents per Ib. 



Phosphoric acid. Potash. Value of 100 Ibs. 



Beech 5-3 Ibs. 16-1 Ibs. $1.51 



Birch 8-5 



Oak 5-5 



Walnut 12-2 



Poplar 13-1 



Apple 4-6 



Red Pine 5'1 



Coal Ashes (anthracite) *5 



Peat " 2-0 



11:6' " 1.45 



10-0 " 1.05 



15-3 " 1.77 



14-0 " 1.71 



12-0 " 1.16 



5-2 " .64 



0-15 " .3 



0-2 " .11 



The phosphoric acid contained in ashes, is 

 combined with peroxide of iron, magnesia and 

 lime; but as it is in a finely divided state, the 

 action of the carbonic acid generated in the com- 

 post pile will liberate it from its bases, and 

 render it immediately available to plants in a 

 soluble state, worth 12 J cents per Ib. The 

 leaching of wood ashes does not remove any of 

 the phosphoric acid, nor all of the potash ; this 

 fact explains the value of what is termed spent 

 ashes as -a manure. Hence, formers can see the 

 importance of emptying their old ash gums and 



