50 PHYSICAL CONSTITUTION OF SOIL 



a heavy black powder, which yields a sublimate of sulphur 

 when dried and heated in a glass tube (Jour. Chem. Soc. 

 1864,379). 



Odour of Soil. According to Berthelot and Andre* (Compt. 

 rend., cxii. 598) the characteristic odour of soil is due to 

 a volatile organic substance, which can be distilled in the 

 presence of water at the temperature of 60 C. The chemical 

 nature of this body has not been satisfactorily ascertained ; 

 it is said to belong probably to the aromatic family. 



