52 WARM SPRINGS. 



starts, and the larger the hollows in which it had 

 been collected before its escape. 



Since, however, it often happens that a boring 

 cuts through several water-beds one after the other, 

 it is easy to understand the very common case «of 

 springs of different temperature rising in the 

 same neighbourhood, and even quite close to- 

 gether. 



Springs occur everywhere, which have a con- 

 stant temperature, that is, one not affected by the 

 changes of the seasons. By far the greatest num- 

 ber of them are warmer than the mean temperature 

 of the soil out of which they rise. These must 

 therefore have got part of their heat from the store 

 within the earth, some more, some less, according 

 to the depth of their source : and all such must 

 come up from depths below the limit of the in- 

 fluence of the external heat. If this were not the 

 case, their temperature must change with the 

 seasons of the year. 



The springs named in the following table belong 

 to this class, as appears from a comparison of their 

 temperature with that of the soil at their mouth. 

 They are a few instances chosen from a great num- 

 ber, all of which would serve equally well as proofs, 

 that springs which are warmer than the soil out of 

 which they flow, are to be found of all tem- 

 peratures within the limits between which water 

 remains liquid. 



