20 



weeks, adding a little water, if it, on examination, appears to be nearly 

 dry. 



WOOD ASHES. 



Wood ashes are our great home source for potash. These are brought 

 into the market from several sources. " Wood ashes," says Professor 

 Goessimann, "have an agricultural value much above their chemical 

 value." Professor Gregory adds that " the principal reason of this is 

 that they contain not only potash but all the elements of plant food 

 except nitrogen, and these in just the same proportion as they exist in 

 nature, with the additional advantage of having them in a very fine 

 state of subdivision." 



The wood of different trees differ not only in the proportion of potash, 

 lime, and phosphoric acid in their ashes, but also in the quantity of 

 their ashes in equal quantities by measure of wood. 



COAL ASHES. 



Coal ashes contain no appreciable amount of potash; the chief ingre- 

 dient is silica. They contain also some lime and magnesia. The trace 

 of potash comes from the wood used in kindling fires, and the coal itself. 

 Coal ashes prove of but little value on most soils, beyond making heavy 

 soils more open and supplying silica to land of a much like character, 

 still there is considerable of value in them when used in connection with 

 manure. 



