CHAPTER VIII 



VEGETATION- AND THE ATMOSPHEEE 



"ri^HE carbonic acid gas produced simply by the 

 A breathing of the great human family amounts 

 every year to about 160,000,000,000 cubic meters, 

 which represents 86,270,000,000 kilograms of burnt 

 carbon. Piled up, this carbon would form a moun- 

 tain one league round at its base and between 

 four hundred and :five hundred meters high. So 

 much carbon is required by man to maintain his 

 natural heat. All of us together eat this mountain 

 of carbon in our food and in the course of the year 

 dissipate it all in the air, a breathf ul at a time ; after 

 which we immediately begin the dissipation of an- 

 other mountain of carbon. How many mountains of 

 carbon, then, since the world was created, must man- 

 kind have exhaled into the atmosphere ! 



"We must take account, too, of the animals, which, 

 collectively, those of the land and those of the sea, 

 use up a big mountain of combustible matter. They 

 are much more numerous than we ; they inhabit the 

 entire globe, both continents and seas. What a 

 quantity of carbon it must take to sustain the life 

 of our planet! And to think that it all goes forth 

 into the air, as a deadly gas, of which a few breaths 

 would cause death ! 



"Nor is that all. Fermentation, as in grape- juice 



42 



