ON THE CHEMICAL CONSTITUENTS OF SOILS. 



241 



Humus, soluble in alkalies 



Humus 



Nitrogenous organic matter 



Subsoil of the same field at a depth 

 100 parts consist of: — 



Very fine siliceous sand with scales of mica 

 Earth separated by the sieve 



100 parts of the earth contain : — 



Silica .... 



Alumina .... 



Peroxide and protoxide of iron 



Peroxide of manganese 



Carbonate of lime . • 



Carbonate of magnesia 



Potash, combined with silica 



Soda, principally combined with silica 



Phosphoric acid, combined with lime 



Sulphuric acid, idem . 



Chlorine in common salt 



Humus, soluble in alkalies 



Humus, with nitrogenous organic matter 



1-160 



. 1100 



0-208 



100000 



of two feet. 



2-408 

 97-592 



100-000 



59-581 

 3-224 

 4-896 

 0-720 

 17-953 

 11075 

 0150 

 0-891 

 846 

 0-0( 

 0- 

 0-536 

 0-120 



)-064 

 )'O0S 



100-ooa 



BELGIUM. 



38. Surface-soil of a field distinguished for its fer- 

 tility. It had received no manure for twelve years pre- 

 vious to the time at which the analysis was executed. 

 The rotation of crops for the latter nine years was as 

 follows : — 1. beans, 2. barley, 3. potatoes, 4. winter 

 barley with red clover, 5. clover, 6. winter barley, 

 7. wheat, 8. oats ; during the ninth year it was 

 allowed to lie fallow. The soil is more clayey than 

 loamy, and of a very fine grain. Water extracted 

 from the soil, 0'013 soda, 0*002 lime, 0-012 magnesia, 

 0-009 sulphuric acid, 0-003 potash, 0-003 chlorine, 

 with traces of silica and humus. 100 parts con- 

 tained : — 



Silica 



Alumina 



Peroxide and protoxide of iron 



Peroxide of manganese 



Carbonate of lime 



21 



64-517 

 4810 

 8316 

 0800 

 9-403 



