CHAPTER XIV 



Plants and the Atmosphere 



The carbonic gas produced by the breath of 

 the human race annually is equal to that 

 produced by the consumption of eighty-five 

 millions of tons of coal. This amount of coal 

 would form a mountain one mile in circum- 

 ference at the base, and between four and five 

 hundred yards in height. This is the amount 

 of fuel required to maintain the natural heat 

 of man. We eat this mountain of carbon 

 among us in our food, and at the end of the 

 year, having dispersed it in the air in puffs 

 of carbonic gas, we proceed at once to attack 

 another. Think how many mountains of 

 carbon the human rare has breathed into the 

 atmosphere since the beginning of the world. 

 We must also reckon the animals, both of 

 land and sea, which must use up a goodly 

 mountain of fuel ; for they are far more 

 numerous than ourselves, occupying the whole 

 of the globe— continents and oceans. All 



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