44 Mr. West on Natural Waters. 



taken up, and that it is probable the celebrity of these waters 

 for such purposes depends on three circumstances, the real 

 increase of solvent power ; the darker colour, giving the ap- 

 pearance of greater strength ; and the sensibility of the palate 

 being increased by the soda. 



3. On the Gaseous Contents of Waters. 



The gases usually found in such waters as are commonly em- 

 ployed for other than medicinal purposes are, carbonic acid 

 gas, azote or nitrogen and oxygen. 



In the waters containing soda, there are commonly small por- 

 tions of sulphuretted hydrogen and of carburetted hydrogen, but 

 these soon escape on exposure to the atmosphere, leaving the 

 water free from its original unpleasant smell. Oxygen gas is 

 less frequent and less abundant than might be supposed. In 

 many cases I have proved its absence, by introducing into the 

 water substances which readily absorb oxygen, by exposing to 

 such substances the gas separated by boiling, and by exploding 

 a mixture of the gas with a known quantity of oxygen, and 

 more than its equivalent of hydrogen. This absence of oxygen 

 is easily accounted for, where substances exist which would at 

 once combine with it, as oxide of iron, or sulphuretted alkalies ; 

 but I have had the same results in cases where it might have 

 existed without interfering with the constituents of the water. 



From its absence under these circumstances, as well as upon 

 other grounds, we may infer that the gases disengaged from 

 spring water are not absorbed from the atmosphere, but are 

 formed and taken up by the water while in the earth. Stand- 

 ing water and streams, however, undoubtedly absorb air. Dr 

 Ure states, that he obtained from such waters about l-35th of 

 their bulk of gases, of which from l-20th to l-10th was car- 

 bonic acid, and the remainder common air. He does not, how- 

 ever, say whether he tried any experiments to ascertain this 

 last point, or only assumed it to be so. I have invariably 

 found less oxygen, in proportion to the nitrogen, than in air, 

 and from . the principles which determine the absorption of 

 gases by water, it should be so. I have also always obtained 



