^7(> On the Absorption of Gases 



In tliree months the whole surface has been to- 

 vered with a pellicle, and no oxygenous gas what- 

 ever was found in the water. It was srrowu 

 offensive, but not extremely so ; it had not 

 been contaminated with any material portion 

 of. metallic or sulphureous mixtureis, ©T any 

 other article to which the effect "^rould be 

 ascribed.* The quantity of azotic gas is not 

 materially diminished by stagnation, if at all. — 

 These circumstances, not being duly noticed, 

 have been the source of great diversity in the 

 results of different philosophers upon the 

 quantity and quality of atmospheric- air in 

 water.- ' By article 4, it appears that atmo- 

 spheric uir expelled from water ought to have 

 S8 per cent, oxygen ; whereas by this article 

 air may be expelled from water that shall 

 contain^from 38 to per cent, of oxygen. — 

 The disappearance of oxygenous gas in water, 

 I presume, must be owing to some impurities 

 in the Water which combine with the oxygen. 

 Pure rain water that had stood more than a 

 vear HI ^rn earthenware bottle had lost nonfe of 

 its oxygen. 



1 1. If water free from air be agitated with 

 a 6m'airf)ortion of atmospheric air (as 4r ^^ i^s 

 bulk) the residuum of such air will have pro- 

 portionally less ; oxygen than the original: If 



* It was drawn from a leaden cistern. 



