276 ANALYSES OF SOILS. 



The influence of this rock upon vegetation is much less than that of the preceding. 

 There is not only a change in the constitution of the limestone, but it is quite ditferent in 

 its texture. Magnesia is no longer an essential element, and the rock 1ms become hard 

 and little subject to disintegration. It is nearly a pure limestone, and the soils upon it are 

 drier, and perhaps more friable ; but they do not retain so firmly the roots of wheat, and 

 hence the crop is more liable to injury from late frosts. Many wide fissures e3dst in this 

 rock, through which the surface water passes, and hence there is often a deficiency. 



The Onondaga limestone may be regarded as a pure calcareous rock, or as pure as 

 chalk and nK)st limestones which are employed for quicklime. 



ANALYSIS OF FIFTY PARTS. 



Hygrometric water 0'46 



Organic matter 0-50 



SJlex.... 1-87 



Alumina and protoxide of iron 0-09 



Phosphate of lime __. 0-03 



Carbonate of lime 44-50 



Carbonate of magnesia 2-00 



49-39 



Composition of the soils of the wheat district. 



The first analysis given below, isof a soil of the red shale near Canastota, and which 

 was derived mainly from it. Its composition may be compared with that of the rock from 

 which it is derived. 



ANALYSIS ONE HUNDRED GRAINS. 



Water of absorption 1-50 



Organic matter 2-50 



Silex 85-00 



Peroxide of iron and alumina 8-12 



Carbonate of lime 2-17 



Magnesia 0-12 



Phosphate of alumina 0-50 • 



99-91 



There is a loss of lime and magnesia in the process of disintegration. 



A practical suggestion of some importance grows out of these analyses, viz. that il 

 would be profitable to spread the decomposing shales over the soils wherever they are 

 accessible. The lime and magnesia might be supplied at a cheap rate. The advantage 

 arising from this procedure consists in supplying lime in a finely divided state. Where 

 wood is plenty, the condition of the materials would be improved by burning : a larger 

 amount would become soluble by the process. 



We may now stop and consider for one moment the state and condition of the particles 



