226 ON THE CHEMICAL CONSTITUENTS OF SOHLS. 



which had been left without manure, as well as on 

 those manured with bone-dust, potash, ammonia, and 

 common salt, the clover scarcely appeared above 

 ground. The divisions of the field, which had been 

 manured in the first year with peat-ashes, ammonia, 

 and ashes of wood, were sown with buckwheat after 

 the removal of the first crop of clover. The buck- 

 wheat succeeded very well on all the divisions, yet 

 a marked difference was perceptible in favor of the 

 portion treated with ammonia. These experiments 

 show us, that a dressing of lime did not completely 

 remove from the soil its tendency to impart rust to 

 the plants grown upon it. Nevertheless it is highly 

 probable, that as soon as the protoxide of iron 

 became converted into the peroxide by exposure to 

 the atmosphere, lime would possess more power in 

 decomposing the phosphate of iron. 



14. Subsoil of a loamy soil in the vicinity of 

 Brunswick. It is remarkable from the circumstance 

 that sainfoin cannot be cultivated upon it more than 

 two or three years in succession. The portion 

 analyzed was taken from a depth of five feet. 100 

 parts contained : — 



Silica with very fine siliceous sand . . 90*035 



Alumina . . . . . 1*976 



Peroxide of iron . . . , 4700 



Protoxide of iron . , . ,1115 



Protoxide and peroxide of manganese • 0-240 



Lime ...... 0022 



Magnesia . . . . . 0«115 



Potash and soda • . . . 0-300 



Phosphoric acid, combined with iron . . 0-098 



Sulphuric acid (the greatest part in combination 



with protoxide of iron) . . . 1*399 



Chlorine . . . . .a trace 



100000 



Now the results of the analysis give a suflScient 

 account of the failure of the sainfoin. The soil 

 contains above one per cent, of sulphate of the pro- 

 toxide of iron (^green vitriol of commerce), a salt 

 w^hich exerts a poisonous action upon plants. Lime 

 is not present in quantity sufficient to decompose 



