206 MB. T. HOPKINS ON THE FALLS OF BAIN IN CUMBEBLAND. 



mass of air being unable to pass over it, until such a height 

 was attained as would leave little uncondensed vapour ex- 

 isting in the air. In sach a situation it is evident, that one 

 gauge placed at a low level in front of the cliff, might receive 

 more rain than another fixed at any height above it. And 

 it is equally clear, that when rain is formed whilst pass- 

 ing over an elevated ridge, that rain might be received 

 either in a gauge placed beyond it, only a little lower, or 

 in one not farther beyond it, but fixed in a deep valley 

 below, as is, in fact, the case with the gauge at Seathwaite. 

 We may therefore conclude, that in a country containing 

 lofty mountains and deep valleys, with much irregularity of 

 surface, the height of the gauge into which rain falls does 

 not indicate the elevation at which it was formed — that 

 elevation being determined by the laws of cooling of the 

 aqueous vapour that is contained in our mixed atmosphere, 

 whilst the vapour is diflfused through the gases. 



