124 



ICE AND GLACIERS. 



left behind them a wooden ladder. This was at the 

 foot of the Aiguille Noire, where the fourth band of the Mer 

 de Grlace begins ; this line thus marks at the same time 

 the direction in which ice travels from this point. In the 

 year 1832, that is, forty-four years after, fragments of 

 this ladder were found by Forbes and other travellers 

 not far below the junction of the three glaciers of the 

 Mer de Grlace, in the same line (at s, Fig. 19), from 



FIG. 19. 



which it results that these parts of the glacier must 

 on the average have each year descended 375 feet. 



In the year 1827 Hugi had built a hut on the central 

 moraine of the Unteraar Glacier for the purpose of 

 making observations ; the exact position of this hut was 



