The Story-Book of the Fields 



this carbon to support life ! And all this 

 passes into the air as a poisonous gas, of which 

 a few breaths would kill you at once. 



And this is not all. Fermenting matters, 

 such as the juice of the vintage, or the dough 

 of bread, and substances which are consumed 

 by rotting, such as manure, produce carbonic 

 acid gas. With a very moderate amount of 

 manure an acre of cultivated ground will give 

 out daily one hundred cubic yards of carbonic 

 acid gas. 



The wood, charcoal and coal which we con- 

 sume in our houses, and in the great industrial 

 furnaces, also supply the air with noxious 

 gas. Only think of the amount of carbonic 

 acid gas poured into the atmosphere by a 

 furnace where the coal is thrown in by cart- 

 loads. Think of the volcanoes, those gigantic 

 natural chimneys, which in one eruption emit 

 amounts of gas compared to which those 

 which we have mentioned are of no account. 

 It is quite evident that the atmosphere is 

 constantly receiving torrents of carbonic acid 

 gas which defy all computation. And yet 

 animals have nothing to fear, now or in the 

 future ; for the atmosphere while constantly 

 poisoned is also constantly purified. 

 And who is the providential cleanser 



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