362 



ILLUSTRATIONS OF THE 



to lakes in general, fome apparent 



ption 



occur, m 



hich the progrefs of draining and 



filling up feems to have been fufpended 



o have g 



in a contrary diredi 



Thefe 



ptions confift of the lakes which appear 



h 



dag 



quantity 



f 



than was fufficient to have filled them up 

 for example, is 



ceives 



the Rh 



the Lake of Ge 

 le defcending fr 



. St 

 hich 



the Vallai 



t 



one of the deepeft and longeft vallies on the fur- 

 face of the earth. Now, if this valley, or even 



ge proportion of it, had been 



e 



ated by 



the Rhone itfelf, as 



theory leads us to fap 



Dofe 



ght to h 



been entirely fill 



ed up, becaufe the materials brought down by 

 the river feem to be much greater than the lake, 



any reafonabie fuppofition concerning 



ginal magnitude, can poffibly h 



d 



What, then 



ay be faid, ' h 



become of 



that the Rhone has brought down and depofi 



ed 



It : 



•? 



Th 



lak 



at th 



moment retains, 



than 1000 



in fome places, the depth of more 

 feet ; and yet, of all that the Rhone carries in- 

 to it, nothing but the pure water iffues. If 

 it has been continuing to diminifh, both in 

 fuperficial extent and in depth, from the 

 when the Rhone began to run into it, what mult 



time 



? 



Iiave been its original dimenlions : 



I 



/ 



