252 ALL EXPERIMENTS USEFUL. 



upon the examination of which time and labour in making field 

 experiments might be usefully expended. It is sufficient for 

 me, however, to repeat what I have elsewhere stated, that there 

 is scarcely a single practical operation among the many with 

 which the farmer is daily occupied, or a single opinion by which 

 the field-culture of his land is influenced the economical value 

 of which may not be tested by rigorous experiment, and in 

 regard to which field trials carefully conducted and regulated 

 by weight and measure, would not supply valuable additions to 

 our existing stock of certain knowledge. 



