586 THE PHILOSOPHY OF FARMING. 
room for more material. This leads us to con- 
sider the nature of aeration as the vehicle of the 
supply of material to the plant within the soil. 
Physiology and Chemistry teach us that aerial 
matter contributes more to the structure of plants 
than fluid matter does. Fluid matter is required 
more for furnishing, than building up the fabric 
—more for storing up properties and carrying 
forward supplies—than contributing supplies 
itself. Hence, the absolute necessity of a con- 
stant accession of aerial matter, which may be 
carried into the structure whenever it may be 
wasted, and to the place where most wanted. 
Air brings the material from a distance to the 
plant; and water carries it forward within the 
plant. The more, then, aerial matter has access 
to the plant, the more material it will bring to 
the plant; for water to serve in the construction 
of the plant and distribute throughout it. Hence, 
the benefit of draining. When drainage is per- 
fect, it carries away rapidly the superfluity of 
water within the soil: air immediately occupies the 
spaces within the soil, previously held by the 
water; and, therefore, carries material thither, 
where it was not before. The roots of plants 
follow this change. A greater space is brought 
