L">6 HATCH EXPERIMENT STATIOX. [Jan. 



represent the present general chemical character of the sub- 

 stances, and would therefore be of more practical value. 



It must l)e understood that the chemical character of many 

 of the refuse substances used for manurial purposes is con- 

 stantly undergoing changes, due to frequent variations in the 

 parent industry. 



As a rule, in all succeeding analyses the essential con- 

 stituents are determined and stated ; blanks do not imply 

 the absence of the non-essentials. 



