230 



HELMHOLTZ 



filled with ice up to the Molkencur, or higher, so that the 

 whole town, with all its steeples and the castle, is buried 

 deeply beneath it; if, further, you imagine this mass of ice, 

 gradually extending in height, continued from the mouth 

 of the valley up to Neckargemiind, that would about corre- 

 spond to the lower united ice-current of the Mer de Glace. 

 Or, instead of the Rhine and the Nahe at Bingen, suppose 

 two ice-currents united which fill the Rhine valley to its 

 upper border as far as we can see from the river, and then 

 the united currents stretching downwards to beyond As- 



FIG. 107 



mannshausen and Burg Rheinstein; such a current would 

 also about correspond to the size of the Mer de Glace. 



FIG. 107, which is a view of the magnificent Corner Glacier 

 seen from below, also gives an idea of the size of the masses 

 of ice of the larger glaciers. 



The surface of most glaciers is dirty, from the numerous 

 pebbles and sand which lie upon it, and which are heaped 

 together the more the ice under them and among them melts 

 away. The ice of the surface has been partially destroyed 

 and rendered crumbly. In the depths of the crevasses ice is 

 een of a purity and clearness with which nothing that we 

 are acquainted with on the plains can be compared. From 

 its purity it shows a splendid blue, like that of the sky, only 

 with a greenish hue. Crevasses in which pure ice is visible 

 in the interior occur of all sizes; in the beginning tKey form 



