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 tW. 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. 



