THEORY AND PRACTICE. 95 



and contraction suited, therefore, to a medium in 

 which moisture should be ever on the move, down- 

 ward by gravitation, or upward by capillary attrac- 

 tion. This is the true condition of the soil demanded 

 of the mechanical department of husbandry. "Pul- 

 verize your soil deeply," said Jethro Tull, who thought 

 that plants lived upon fine particles of mould : and 

 he said rightly, but in so far as he said only half, 

 and thought that was ALL, he thought wrongly.* 



But not more wrongly than every Farmer thinks 

 who fancies that the bulk of his manure is its valua- 

 able part. He rather hugs his enemy in this, as he 

 has done in other matters. The T)ulk and weight of 

 Farm-yard manure is simply the carbon which it 

 obtained, last year from the Atmosphere; all of 

 which must go through a long process of decay 



* This is a beautiful, as well as philosophical illustration in 

 vegetable physiology connected with the growth of plants ; 

 and no man can be an intelligent husbandman who is ignorant 

 of the principles which govern their structure and growth. 

 Experience and practice, long continued, have made many 

 "good farmers," as the world has it; but no man, let his 

 particular practice on certain soils bo ever so good, can apply 

 the same practice to different soils with equal success. 

 Therefore a degree of scientific knowledge is wanting to 

 make an equally good husbandman on the various soils which 

 may be brought under his supervision. ED. 



