342 Mineral Manures, and the Value of 



might suppose would be barren, without the usual propor- 

 tions of siliceous and aluminous matter, is, on account of its 

 great fineness and the remaining ten per cent, of organic and 

 inorganic constituents, enabled to produce the best crops upon 

 the island. 



These advantages of fineness, it is evident the Ohio soils 

 loill ahcays possess, as it cannot he exhausted hy any system 

 of agriculture. To this point I wish to call especial atten- 

 tion, since if due regard be paid to the supplying of these 

 soils with the necessary quantities of organic and inorganic 

 nutriment, they must and always will be unrivalled for fertil- 

 ity. An examination of the siliceous insoluble constituents 

 of these soils, leads to the belief, that they have not been de- 

 rived from the disintegration or decay of any underlying or 

 contiguous rocks, but from materials brought from a distance. 

 The rocks of Ohio are for the most part carbonate of lime, 

 and yet in only one of the soils examined, a subsoil, could 

 the slightest trace of carbonic acid be detected. The method 

 adopted for testing, was by placing the soil in a favorable 

 light upon a watch-glass, covering with dilute warm acid, 

 and noticing carefully for the appearance of effervescence. 

 In this way the most minute quantity of carbonic acid could 

 not fail of being detected. In the examination of the soils 

 of Massachusetts by Pres. Hitchcock, the same remarkable 

 deficiency of carbonates, even in soils resting upon carbonate 

 of lime rocks, was noticed. The same conclusions have, I 

 understand, been arrived at by Dr. D. D. Owen, from an ex- 

 amination of the soils of Iowa and Wisconsin. From these 

 facts we believe that the alkaline and earthy carbonates are 

 to a much greater extent wanting in arable soils than is gen- 

 erally supposed. This supposition, however, should perhaps 

 be confined to the northern portions of this country, which 

 have soils resulting mainly from materials distributed by the 

 drift agency. 



In the analyses of these soils, the separation, and estima- 

 tion of the comparative value of the organic constituents has 

 been made by means of alkalies. This plan seems to pos- 

 sess advantages over that of any other. A given portion of 



