24 
THE farmer’s manual. 
blood in the lungs, and thus passes into circulation, 
giving vigour, life and energy to the whole system, 
and again passes off through the secretions of the 
body, and commixes with common air. It is a well 
known fact, that the foliage of plants and trees, pro- 
duces in constant succession, and entits into circula- 
tion, this, vital, or oxygen air, and of course it must 
follow, that by the inhaling vessels, both of the roots, 
trunk, branches and foliage, this oxygen, or vital air, 
is admitted into circulation, and becomes the essen- 
tial, or vital principle of vegetation. 
Whatever renders the earth loose, so as to admit a 
free circulation of air to the roots of plants, will best 
promote the great system of the economy of nature, 
and thus render it active and vigorous, by the free 
circulation of vital or oxygen air; the same as in 
the animal world. Whatever causes the greatest de- 
gree of fermentation, when buried in the earth, best 
promotes this economy of nature, by rendering the 
earth loose, for the free admission and circulation of 
air and moisture, and thus, by their chymical combi- 
nation, promotes the growth, and forms the substances 
of plants and frees ; hence the reason why animal 
substances produce the best effects in the promotion of 
vegetation, because they cause the greatest degrees of 
fermentation, in their dissolution ; and hence the rea- 
son why the growth of trees and plants never exhausts, 
or diminishes, the weight of earth in which they grow. 
Electricity has its full share in producing the 
above eflects, both in the animal and vegetable 
kingdoms ; but not upon the same principles of oxy- 
gen, because electricity is the most subtle and 
powerful of all substances, and pervades with equal 
ease all bodies, w hether hard or soft : not so with 
oxygen, it cannot commix with the earth, and thus 
become food for the roots of plants, any further than 
this earth is rendered light, or pervious, for the admis- 
sion of common air ; hence the reason why frequent 
ploughings, and fermenting substances promote ve- 
