THIRD CHAPTER. 



CARBON, ITS NATURE AND ACTION. 



'T'HE action and influence of these various elemen- 

 tary bodies upon each other, and upon other 

 substances, are a fit subject for further consideration. 

 In charcoal, as already said, we have a simple but 

 impure form of carbon. From the fact that carbon 

 forms nearly one-half, by weight, of the dry matter 

 of all plant products, it would be but natural to 

 suppose that charcoal would be one of the most 

 effective plant foods, and the most important ingre- 

 dient in fertilizers. This, however, is not the case. 

 Carbon is entirely insoluble in water. Air, under 

 common temperature, does not effect it. 



We might grind charcoal ever so fine, and put it 

 ever so close to the roots of plants; these latter 

 could not possibly take it up into their circulation. 

 Now let us take this charcoal (or dry wood, or any 

 other substance containing carbon) and put it upon 



live coals in the stove. The draft in 

 ^ AciT'^ front admits air freely, and the oxygen 



of this air rushes upon the carbon and 

 devours it; that is, combines chemically with it, 

 forming the gaseous compound "carbonic acid." 

 This escapes through the chimney, and is diffused 

 through the atmosphere. It is a colorless gas with 



