588 THE PHILOSOPHY OF FARMING. 
tity, but in the quality of the grasses and herbage 
thereon, proceeds from the simple effect of this 
aeration of the soil, in all instances where no 
tillage besides could be afforded still more to aid 
nature in bettering the produce. And much of 
the beneficial effects of falls of rains and showers, 
is occasioned by the displacement of air within 
the soil, already acted upon by the roots of 
plants, and the consequent replacement of fresh air 
from above, when that rain percolates and filters 
down into the subsoil, or flows into drains. 
But the advantages of as full an areation of the 
soil as possible to be derived from the constant 
accession of nutritive elements to the roots of 
plants contained in the air, are few, compared with 
those which are effected within the soil itself by 
the agency of the atmosphere. Complete dry- 
ness prevents the decay of defunct organised 
structures. Supersaturation of moisture restrains 
the process of such decay. While the joint 
action of a modicum of moisture and of air, accel- 
erates that process. Indeed, all enemacauses, 
whatever, depend upon the presence of the air 
for their action. Out of air spring alike life and 
destruction ; and the result of the one, is but the 
counter action of the other. All organized 
