{ 82 ) 

 rial for the extraction of potassa. In England, 

 ashes are preferred for gravelly soils, and ap- 

 plied every spring in the proportion of forty 

 bushels per acre. 



Leeched ashes. The refuse ashes from the 

 ley vats of soap factories yet retain, besides 

 the soluble salts which escaped lixiviation, 

 carbonate of lime resulting from the caustifi- 

 cation of the carbonate of potassa and insolu- 

 ble salts, such as the phosphates, sulphates 

 and carbonates, with a little silica. In the 

 proportion of 60 to 80 bushels per acre, they 

 extend their fertilizing eJQfects through ten 

 years. 



Peat ashes. These ashes are of advanta- 

 geous application in agriculture. They con- 

 tain lime, sulphate of lime, alkaline chloride, 

 carbonates and sulphates, gelatinous silex and 

 calcined clay. Their precise composition, 

 however, varies with that of the peat, and 

 consequently they are not always uniform in 

 their effects. Generally, they are an excellent 

 substitute for plaster. The ashfes of the pyri- 

 tous turfs contain sulphate of iron generated 

 by the action of the atmosphere upon its sul- 

 phuret, and hence are injurious to vegetation. 

 Good ashes are white and light, and, in a dry 



