the several Gas^s in ih^e Atmosphere, SiS 



separate as in a mixed state, depending" lipon 

 its proper density and temperature. This 

 principle accords with all experience, and I 

 have no doubt will sooi> be perceived and ac- 

 knowledged by chemists and philosophers ill 

 general ; and its application will elucidate 1 

 variety of facts, Avhich are otherwise involved 

 in obscurity. 



The objects of the present essay are, 



1 . To determine the weight of each simple 

 atmosphere, abstractedly y or, in other words j 

 What part of the weight of the whole com^ 

 pound atmosphere is due to azote ; what to 

 oxygen, &c. fee. 



2. To determine the relative weights 6f 

 the different gases in a given volume of at- 

 mospheric air, such as it is at the earth's 

 surface. 



3. To investigate the proportions of the 

 gases to each other, such as they ought to be 

 found at different elevations above the earth*^ 

 surface. 



To those who consider the atmosphere as A 

 chemical compound, these three objects are 

 but one ; others, who adopt my hypothesis, 

 will see they are essentially distinct.— With 

 tespect to the first : It is obvious, that, on my 

 hypothesis, the density and elastic force of 

 each gas at the earth's surface, are the effects of 



