377 



In this funnel ordinary surface-water, flowing along the 

 ice, must necessarily be collected and partly mixed with the 

 hot water of the spring, and this accounts for the variability 

 of the temperature, because the available quantity of surface- 

 water is dependent on the state of the weather and will be 

 augmented by rain in a short time. It is very improbable that 

 the water of the spring itself should contain dissolved oxygen, 

 as this gas is so easily combined with many minerals, but the 

 surface-water is of course saturated with oxygen at the pressure 

 present in the atmosphere. If gas-bubbles are formed ^) and 

 equilibrium obtained the oxygen-tension of such bubbles must 



Spring 



Rock 



Fie. 9. 



correspond to a mixture of oxygen-free water with common 

 surface-water. This is exactly the result of the analyses. 



At the depth where the bubbles are formed the tension of 

 carbonic acid is evidently but at the mouth of the spring 

 it is about 2. This fact is not surprising, for at the mouth 

 the water is mixed with more surface-water and with that 

 portion of the surface-water which has just obtained a high 



') The formation of gas-bubbles indicates in itself that a mixture of hot 

 water with cold may have taken place, because such mixtures, provided 

 that each water was saturated beforehand with a gas (for instance nitrogen ), 

 will always be supersaturated and therefore liable to the formation of 

 gas-bubbles. 



