FERTILIZERS. 29 



very insignificant proportion of the ash-looking mass is 

 ashes from burnt vegetable matter. And such is the fact : 

 the great bulk of it is simple mineral matter from burnt 

 soil, colored red by the action of the fire on the iron that is 

 found in about all soils, the same mineral that makes the 

 white brick turn red in burning. 



COAL ASHES. 



Coal ashes contain no appreciable amount of potash : 

 the chief ingredient is silica. They contain also some 

 lime and magnesia : some assert that there is as high as 

 100 pounds of magnesia to the cord, with 160 pounds of 

 sulphuric acid. The trace of potash comes from the wood 

 used in kindling fires, and the coal itself. Theoretically, 

 coal ashes should prove of but little value on most soils, 

 beyond making heavy soils more open, and supplying silica 

 to land of a muck-like character ; still, there is considerable 

 of value. in them, when used in connection with manure, 

 on some crops, especially potatoes, and around bushes and 

 fruit-trees. Here they serve as a mulch, and, like all 

 mulches, indirectly improve the soil beneath them. Many 

 of the coal ash-heaps in towns are made receptacles for the 

 slaps of the family, which turn them into manure that will 

 pay for carting a mile or two. When night-soil is col- 

 lected, they are valuable for forming the bed to receive it. 

 acting as an excellent absorbent. 



COTTON-SEED HULLS. 



This is one of the sources for potash confined mostly to 

 the South, not only because they are wholly burned there, 

 but because the ashes are oftentimes mixed more or less 

 with coal ashes, and charred and unburnt hulls used in the 

 furnaces of the oil manufactories, where they are largely 

 consumed as fuel. Because of these impurities, they are 



