120 ICE AND GLACIERS. 



is veiled from our eyes. So also it is with glacier 

 chasms. In the lower part of the glacier they yawn 

 before us, threatening death and destruction, and lead us, 

 timidly collecting all our presence of mind, to shrink from 

 them ; thus accidents seldom occur. On the upper part 

 of the glacier, on the contrary, the surface is covered with 

 snow ; this, when it falls thickly, soon arches over the 

 narrower crevasses of a breadth of from four to eight feet, 

 and forms bridges which quite conceal the crevasse, so that 

 the traveller only sees a beautiful plane snow surface 

 before him. If the snow bridges are thick enough, they 

 will support a man ; but they are not always so, and these 

 are the places where men, and even chamois, are so often 

 lost. These dangers may readily be guarded against if 

 two or three men are roped together at intervals of ten 

 or twelve feet. If then one of them falls into a crevasse, 

 the two others can hold him, and draw him out again. 



In some places the crevasses may be entered, especially 

 at the lower end of a glacier. In the well-known glaciers 

 of Grrindelwald, Eosenlaui, and other places, this is facili- 

 tated by cutting steps and arranging wooden planks. 

 Then anyone who does not fear the perpetually trickling 

 water may explore these crevasses, and admire the won- 

 derfully transparent and pure crystal walls of these 

 caverns. The beautiful blue colour which they exhibit 

 is the natural colour of perfectly pure water ; liquid 

 water as well as ice is blue, though to an extremely small 

 extent, so that the colour is only visible in layers of from 

 ten to twelve feet in thickness. The water of the Lake of 

 Geneva and of theLago di Garda exhibits the same splendid 

 colour as ice. 



The glaciers are not everywhere crevassed ; in places 

 where the ice meets with an obstacle, and in the middle 

 of great glacier currents the motion of which is uniform, 

 the surface is perfectly coherent. 



