FORMATION OF ARABLE LANDS. 25 



Bergmann found that one of the most fertile soils in 

 Sweden contained 



Coarse silex .... 30 parts 



Silica .26 



Alumina 14 



Carbonate of lime ... 30 



100 



Giobert analyzed a portion of fertile soil from the neigh- 

 bourhood of Turin, in which the principal earths were in 

 the following proportions, 



Silica 77 to 79 



Alumina 9 to 14 



Carbonate of lime . . 5 to 12 

 The most fertile mixture produced by Tillet, in a great 

 number of experiments which he made at Paris, was com- 

 posed of f of clay, f of finely pulverized limestone, and | of 

 sand. Upon reducing these to their elements, we find 



Coarse silex 25 



Silica .21 



Alumina 16.5 



' Carbonate of lime 37.5 



An excellent soil for wheat, in the neighbourhood of 

 Drayton, in Middlesex, gave f of siliceous sand ; the re- 

 maining f were composed of three earths finely divided, 

 in the following proportions. 



Carbonate of lime .... 28 



Silica 32 



Alumina 39 * 



I do not speak of the water, nor of animal and vegetable 

 remains contained in the soil, and which enter into its 

 composition in the proportion of about y\y. 



I have myself analyzed a very fertile soil formed by the 

 alluvions of the Loire, at a distance of three hundred and 



[* Davy (jigricultvral Chemistry, p. 162,) states this analysis 

 thus, Parts. 



Carbonate of lime 28 



SiUca 32 



Alumina 29 



Animal or vegetable matter and moisture . .11 



— Tb.] 

 3 



