FERTILIZERS. 1 



If we give the bushel of ashes into the hands of the 

 chemist, to tell us what it is made of, he will return us 

 silicon, potassium, calcium, phosphorus, sodium, alumin^ 

 ium, sulphur, iron, chlorine, magnesium. These are the 

 elements that all plants take from the soil. The soil itself 

 obtained them originally from the ledges of solid rock, 

 which through eons of years have been slowly disinte- 

 grating and decomposing. Geology tells us, that, by the 

 action of the drift waves of ancient eras, mountains of 

 water six thousand feet or more in height swept from the 

 north, breaking down, filling up, and smoothing off, the 

 ragged, craggy surface of the ancient lava-covered earth ; 

 by later glacial action, and that of water and frost, which 

 extend into the human period, the rocks have been ground 

 up, and scattered over a large portion of the surface of 

 our planet in gravelly hills and plains, covered more or 

 less by vegetable matter, through which protrude, in places^ 

 the rocky ribs of the ancient earth. This soil is but a 

 sprinkling on the surface of our globe. At a depth of but 

 a few hundred feet, at the utmost, on any spot of its mil- 

 lions of miles of surface, we would strike rock, solid to 

 the great lava centres. 



The principal ledges from which have come originally 

 the mineral matter of the soil, are of the granite class. 

 These yield the minerals felspar, mica, hornblende, and 

 quartz ; and they, the silicon, potash, iron, alumina, soda, 

 lime, and manganese. The sedimentary rocks, of which the 

 various slates are a type, have the particles in a finer form 

 than they exist in the parent primary rocks ; and hence the 

 soils formed from these, such as the clays, have the mineral 

 constituents in a finer condition. But the finest subdivis- 

 ion of all, in which the mineral matter of the soil exists, 

 is that supplied by dead plant and animal life, into whose 

 structure the minerals entered in so fine a state as to be 

 held in solution by water. 



