40 Professor Bronn on some Geological and Vhysical 



covering of ice " which again suddenly altered the relations 

 of the climate of Switzerland, and gave rise to those frequent 

 oscillations and variations in the ice-crust of Switzerland 

 caused by the alternations of season and changes of weather.'* 

 But if the elevation of the Alps could have had an influence 

 on the climate, that can have been only local, and not one 

 destructive of the icy envelope of the whole northern and 

 temperate zone ; and it can only have had a refrigerating in- 

 fluence and not a heating one, because we still perceive that 

 thus Switzerland became an actual repository of eternal snow 

 and ice, under all circumstances, in the midst of the tempe- 

 rate zone, and operated with a refrigerating influence on the 

 surrounding countries ; and therefore Charpentier* has cor- 

 rectly assumed for his theory that a former greater elevation of 

 the Alps may have been the cause of the former greater extent 

 of the glaciers, — a supposition which we find answered by 

 Agassiz by the argument that " nothing favours the idea" (p. 

 281). There still remain for us, then, two investigations in 

 relation to the theory of the ice-period : that as to the last- 

 mentioned question, viz., if really there is nothing to support 

 the notion of a former greater height of the chain of the 

 Alps ; and that as to the actual causes which are capable of 

 explaining the alterations of climate since the formation of 

 the diluvium. 



If the Alps rose in a burning liquid condition, as is assumed 

 by Agassiz, there can be no doubt that originally they actually 

 had a greater height than they have at present ; and this be- 

 cause every body expands by heat, and contracts by cold. I 

 shall only adduce the observations of Professor Bischof, from 

 which it appears that granite, in its passage from the liquid to 

 the crystalline state, is contracted by 0.25 of its volume. At 

 the time when the Alps were covered with a crust of ice, their 

 surface must, it is true, have been completely cooled ; but this 

 did not prevent their interior being still in a red-hot state, 

 and their nucleus being liquid ; just as we find Etna and many 

 other active volcanos covered with eternal snow. In this 

 way, however, the largest portion of the contraction must pre- 



* Jahrhiich, 1837; p. 471. 



