34 University Geological Survey of Kansas. 
that the gases argon and helium dissolved in the water have a 
therapeutic effect. 
Oxygen, Carbon Dioxid, Hydrogen Sulfid, etc. 
All water contains in solution the gases that are in the air in 
certain proportions. In very pure water the amount of oxygen 
to nitrogen is: 
ORy BONE MANE Mee onet ye UNA Tana Halted 30.1 
DIT OySXEy OMI a ANIA el OMIM Lid aa 64.9 
100.0 
A thougand cubic centimeters (about a quart) of pure water. 
dissolved 17.95 cc. of air. Jf water is impure it will not dis- 
solve so much of the oxygen; that is, the proportion between 
the two gases will change, as the oxygen is used up in oxidizing 
the organic or impure matter. 
Since the air that is dissolved in water is richer in oxygen 
than ordinary air, it is better adapted to the purpose of furnish- 
ing oxygen to fish for breathing. When the fish are in a con- 
fined volume of water they soon exhaust the water of oxygen ; 
so this is replaced by blowing air into the water in aquaria, or 
by growing plants in the water, which also suppy oxygen. 
There seems to be a well-settled opinion that carbon dioxid, 
hydrogen sulfid and marsh gas are derived not from the air but 
from the soil, on account of certain changes that take place 
far below the surface of the earth. As natural gas consists 
largely of marsh gas (CH,), it is evidently formed at a depth of 
hundreds of feet below the surface, and it would not be incor- 
rect to affirm that. the other gases that accompany the marsh 
gas—such as carbon dioxid and carbon monoxid—can be formed 
at great depths. Itis a matter of common observation that 
some mineral wells contain a large excess of carbon dioxid 
which escapes into the air when the water comes to the surface, 
as in the case of the Congress spring and the Hathorne at Sar- 
atoga. This carbon dioxid holds many of the elements in so- 
lution—such as calcium, magnesium, iron and manganese as 
bicarbonates. The less the pressure of the atmosphere the more 
rapidly will the gases be evolved. A familiar illustration of 
this fact is a vessel of water placed under the receiver of an 
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