PEEFACE. 



IN the sixteen years which have intervened between 

 this work and tlie sixth edition of my ' Chemistry 

 apphed to Agricnlture and Physiology,' I have had 

 suflicient opportunity to become acquainted with all 

 the obstacles which are opposed to the introduction 

 of scientific teaching into the domain of practical 

 agriciiltm-e. Among the chief of these may be reckoned 

 the complete separation which has always existed between 

 science and practice. 



There has generally prevailed an idea that a smaller 

 amount of information and intelligence is required for 

 agricultural pursuits than for any other occupation ; nay, 

 that the practical skill of the farmer is only likely to 

 be injured when he has recourse to science. Whatever 

 requires thought and reflection is regarded as theoiy, 

 which being the opposite of practice, must, of course, be 

 of httle value. The natural result of such opinions is, 

 that when the practical man does attempt to apply 

 scientific teaching, he is almost invariably a sufferer. 

 He seems altogether to forget that man does not become 

 intuitively acquainted with scientific teaching, which, 

 like the skilful use of any complex instrument, must be 

 learned. 



