THEORY AND PRACTICE. 71 



AIR, so the Roots arc 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 con- 

 traction, suited therefore to a medium in which 

 moisture should be ever on the move, downwards by 

 gravitation, or upwards by capillary attraction. This 

 is the true condition of the soil demanded of the me- 

 chanical department of husbandry. ' Pulverize 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 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 

 with these mineral and ammoniacal substances, the 



