38 PHYSIOGRAPHY. [CH. ii. 



water not only from its tributary streams, but from springs 

 gushing up in the very bed of the river. These springs 

 are in some cases of enormous magnitude, especially 

 between Wallingford and Reading, and thus swell the 

 volume of the river to no inconsiderable extent. 



Enough has been said, in this chapter, respecting the 

 nature and origin of springs, to show that all such sources 

 of water owe their origin, directly or indirectly, to the 

 rain which falls upon the collecting ground, and finds its 

 way through the pores and cracks of the rocks beneath. 

 Proximately, the source of the Thames and other rivers is to 

 be found in springs ; but, ultimately, it must be traced to 

 rain. It is true the springs feed the river, but it is the rain 

 that feeds the springs. It will therefore be necessary, in the 

 next chapter, to study the formation of rain and kindred 

 phenomena. 



