THE FEUN PARADISE. 



nation of the oxygen of the air with the carbon 

 of the blood, and is called carbonic acid gas. 

 Were a process of accumulation of this deleterious 

 gas to continue, the equilibrium which makes 

 animal life possible would be destroyed, and that 

 life would cease to exist. But the great plant 

 kingdom requires for a chief part of its suste- 

 nance the very gas which the animal world 

 rejects. The primary 'food of plants is carbon, 

 and the necessary supply is obtained almost 

 wholly from the carbonic acid gas of the atmos- 

 phere. When it is remembered that half of the 

 weight of our forest trees, for instance, consists 

 of carbon, and that the whole of their supply is 

 derived from the carbonic acid gas of the air, it 

 will be recognized to what a large extent the 

 atmosphere is concerned in the manufacture of 

 wood. It is not, however, trees alone, but shrubs, 

 flowering plants, Ferns, mosses, grasses indeed 

 all vegetation, which relies upon the atmosphere, 

 with its freight of carbonic acid gas, for its supply 

 of carbon the material which, furnishing the 

 bulk of their substance to plants, gives to them 

 their strength and stability. 



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