THEORY AND PRACTICE. 71 



with AIR, so the Boots are adapted to WATER : not 

 stagnant water : for the sponge rots which is always 

 saturated, and their myriad fibres are each furnished 

 at the end with a sponge capable of rapid expansion 

 and contraction, suited therefore to a medium in 

 which moisture should be ever on the move, down- 

 wards by gravitation, or upwards by capillary at- 

 traction. This is the true condition of the soil 

 demanded of the mechanical department of hus- 

 bandry. ' Pulverise your soil deeply,' said Jethro 

 Tull, who thought that plants lived upon fine parti- 

 cles 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 valuable 

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

 done in other matters. The bulk 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 before it 

 will have set free the Mineral and Ammoniacal parts, 

 which together constitute, when dissolved by water, 

 the suction-food of roots. 



Liebig asserts, that if the roots are duly supplied 



