Wisconsin State Agricultural Society. 
307 
up the plant; the ox} r gen is set free in the atmosphere. Nature, in 
returning this vegetable matter to the soil, returns this carbon and 
hydrogen in their elementary, uncombined states, and consequently of 
no earthly use as plant-food, or plant-force, until again converted 
into carbonic acid and water. How is this to be done? Nature’s 
method is by the free circulation of atmospheric air in the soil. Let 
us watch, for a moment, this beautiful process. 
For every pound of hydrogen obtained by the plant in the decom¬ 
position of water in its leaves, eight pounds of oxygen are thrown 
off into the atmosphere. The affinity of the atoms of oxygen and 
hydrogen overcome by the sunlight in this process are not destroy¬ 
ed, but wrought up into what we sometimes call chemical tension, 
to be returned again as force, under proper conditions. These sev¬ 
eral elements, according to natural methods, are to brought togeth¬ 
er in the soil, and here the union is to take place. In the union of 
these elements to form water, we must have for every pound of hy¬ 
drogen returned to the soil, eight pounds of oxygen from the atmos¬ 
phere. To what extent the health and vigor of plants depend upon 
this beautiful process of forming water in the presence of their roots, 
we may never know. Not any less important, however, is the for¬ 
mation of carbonic acid by a similar process. 
It is said by good authority, that every acre of strong vegetation, 
takes from the atmosphere, and will—unless man interposes—re¬ 
turn to the soil annually not less than one-half ton of carbon; or 
at this rate fifty tons in a century. For what purpose is this car¬ 
bon returned to the soil? Suppose we take this vegetable carbon 
—charcoal for instance—and put it into the boiler of a locomotive- 
engine, or a steamboat; and then allow the atmosphere free access 
to it, what will be the result? The afhnitv between the atoms of 
oxygen and carbon, overcome by the action of sunlight in the pro¬ 
cess of vegetation, is here restored, and they rush together to form 
carbonic acid. In their combination heat is produced and by a very 
simple process converted into force or motion. Hence the train 
moves, and the boat is urged across the ocean. Or suppose we 
take a portion of this vegetable carbon and feed it to our animals, 
what is the result? This carbonaceous matter is taken into the 
stomach and digested, and when the atmospheric air inhaled by the 
animal is brought in contact with it, it is oxidized, that is, carbonic 
acid is formed, and as a result, heat is generated, which is converted 
