232 



ON THE CHEMICAL CONSTITUENTS OF SOILS. 



tiful crops of peas, beans, lucern, and beet, 

 sieve separates from 100 parts of the soil : — 



The 



Small stones, principally limestone 



Quartzy sand, with a little magnetic iron sand 



Earthy part ..... 



I 

 15 



84 



100 



100 parts of the soil, freed from stones, consists 

 of: — 



Silica, and fine siliceous sand . . . 83*298 



Alumina, combined with silica . . 1 413 



Alumina, partly in combination with humus . 3'715 

 Peroxide and protoxide of iron, in combination 



with silica ..... 0*724 

 Peroxide and protoxide of iron, partly free and 



partly in combination with humus . . 2 244 



Peroxide and protoxide of manganese . 0*280 

 Lime, with coal of humus, sulphur, and phosphoric 



acid ...... 1-814 



Magnesia, combined with silica . . 0*422 



Magnesia, combined with humus . • . 0*400 



Potash ...... 0003 



Soda . .... 0001 



Phosphoric acid .... 0166 



Sulphuric acid . . • . . 0*069 



Chlorine . . . . . . 0*002 



Carbonic acid (as carbonate of lime) . . 0440 



Humus, soluble in alkalies ... 0-789 



Humus, with a little water . . . 3*250 



Nitrogenous matter . . . . 0*960 



Resinous matter . . . . .a trace 



100000 



The subsoil is of the same composition as the sur- 

 face, with this difference only, that it contains more 

 potash, soda, and chlorine,* and is interspersed with 

 fragments of fresh-water shells. Hence it is that 

 the soil produces the deep-rooted plants in such lux- 

 uriance. 



24. Soil of a sterile moor, which had been burned 

 three times, and upon which buckwheat had been 

 cultivated. 100 parts contained : — 



Humus, soluble in alkalies . . . 9*250 



Vegetable remains, charcoal, quartzy sand, and 



earthy particles . . . . . 90*750 



100000 



* The portion of the surface-soil subjected to analysis was taken from 

 the field after long-continued rain. Hence the small quantity of salts 

 of potash and soda. 



