the seve^^l^^Q^^^i^tki^A^osphere. ^ 

 - These may be seen in tlie foUavring Table. . 



Atmospheric aif, l.ooo 



' Azotic ga^, .....1 V()G 



*" Oxygenous gas, .-..<.,..-•..- 1,121 



Carbohic acid gas^ il^i?.::[r 'If?^'^'^ 

 Aqueous vapour^' .'l.V.^.rii.' .700 ;' . "^ 



Hydrogenous gas oil^'^'^ 



' ■ . ' 1 'nrr: 



Kirwan and I^voisier aiia txx^ authorities >{oi 

 these numbers ; except oxygenous gas .atid 

 aqueous vapour. For the former I am ''inn 

 debted to Mr. Davy's Chemical Researches j 



his number is something greater than theirs : 

 I prefer it, because, being determined with, at 

 least equal attention to accuracy with, liie 

 others, it has this further claim for credit, that 

 21 parts of ga$ of this specific gravity, mhicd 

 with 79 parts of azotic gas, make a compound 

 of exactly the same specific gravity as the 

 atmosphere, as they evidently ought to do, 

 setting aside the unfounded notion of their 

 forming a chemical compound. The specific 

 gravity of aqueous vapour I have determined 

 •' , ' ,- ' ■ ' ^ * 



* The specific gravity of hydrogen must be ralcd Coo 

 low : if 100 oxygen f^qoire 1S5 hydrogen by measure, 

 accordinj^ to thi* 89 exy^en wttuKI require only 1 1 hy- 

 drogen to forip water ; whereas €^ require 15. Hydrogen 

 Qught to he found about ^ part of (he weight of common 

 air. 



