110 ACTION OF SALTS. 



soon becomes mild. The value of ashes in agricul- 

 ture, depends upon its being a combination of salts, 

 derived from plants, all of which have a powerful 

 and decidedly beneficial effect. The question is 

 often asked, what is the relative value of spent or 

 leached and unleached ashes. It may be answered 

 by reference to the analysis of ashes. 



Burning reduces these constituents to two classes, 

 ashes and volatile salts. The last are found in soot. 

 The ashes are formed of salts and silicates. These 

 vary in quantity and quality, not only in different 

 plants, but, as is well known, in different parts of 

 the same plant. Let us take oak, beech, basswood, 

 birch, as the types of the composition of hard wood 

 ashes, yellow pine, — (pinus abies) — as the type of 

 soft wood ashes J and wheat straw as the type of 

 the ashes of the grasses. 



The average quantity of ashes from 100 parts of 

 dry oak, beech, birch, &c, is 2*87. Ashes are di- 

 vided by the simple process of leaching, into two 

 parts, soluble and insoluble in water. 100 parts of 

 hard wood ashes thus afford — soluble, 13*57 ; insol- 

 uble, 86-43. 



100 PARTS OF THE SOLUBLE CONTAIN: 



Carbonic acid, 22-70. 



