MANURES. 



35 



manner to his crops, so far as they can be made profitable. 

 We shall first speak of the inorganic manures. 



ASHES. 



If any organic matter, whether animal or vegetable, be 

 burned, an incombustible substance remains behind, called 

 the ash or ashes. This varies in different plants, from less 

 than one, to over twelve per cent, of their whole weight. 

 It also varies with the different soils upon which they are 

 found, with the different parts of the same plant, and in the 

 different stages of its maturity. Thus, plants which grow 

 on peaty or low wet soils, give a less proportion of ashes than 

 those which mature upon soils that are dry, or rich in the sili- 

 cates and salts. The bark, leaves and twigs, give much more 

 of ash than the trunks of trees and stems of plants ; and in 

 their early growth, they yield a much larger proportion than 

 after they have attained maturity. 



The following table, constructed from several reliable 

 sources, but principally from Sprengel, arranged in part by 

 Johnston, will show the relative quantity of ashes found in 

 eome of the more important objects of cultivation. 



grain, beans, peas, straw and 



Included in Potash. 



