BOOK VIII 



THE AIR AND ITS CORPUSCULES. 



The aerial ocean which envelops the earth is from fifteen 

 to sixteen leagues high. It is the medium for diffusing ani- 

 mation and life, and its disappearance would be immediately 

 followed by a general destruction of animals and plants, and 

 the silence of death. 



The vital principle of the air, or oxygen, enters into its 

 composition to the extent of -rV<r. It has been generally 

 thought that this element is found in the same proportion 

 over the whole surface of the globe. According to M. Mar- 

 tins, the air of the Faulhorn, one of the highest mountains in 

 Switzerland, yields the same percentage of oxygen as that 

 of Paris. 



Paradoxes have always had a certain success. Some 

 chemists have maintained that the air in hospitals, drains, 

 and even the foulest places, maintains all its purity. 1 Not- 

 withstanding these different assertions, as a great deal of 

 oxygen is consumed in populous cities, whilst plants are 

 continually pouring it out into the atmosphere, it seemed a 

 priori as if we ought to find more respirable gas in the air 



1 In a prize memoir of a provincial academy, Julia Fontenelle has maintained 

 that the air of hospitals, and even of sewers, is as pure as that of our fields. 



