112 ICE AND GLACIERS. 



below the snow-line on the lower slopes of the mountain, 

 and especially in the valleys, where however being exposed 

 to the influence of a warmer air, it ultimately melts and 

 flows away as water. The descent of masses of snow from 

 their original positions sometimes happens suddenly in 

 avalanches, but it is usually very gradual in the form of 

 glaciers. 



Thus we must discriminate between two distinct parts of 

 the ice-fields ; that is, first, the snow which originally fell 

 called firn in Switzerland above the snow-line, cover- 

 ing the slopes of the peaks as far as it can hang on to 

 them, and filling up the upper wide kettle-shaped ends 

 of the valleys forming widely extended fields of snow or 

 firnmeere. Secondly, the glaciers, called in the Tyrol 

 firner^ which as prolongations of the snow-fields often 

 extend to a distance of from 4,000 to 5,000 feet below 

 the snow-line, and in which the loose snow of the 

 snow-fields is again found changed into transparent solid 

 ice. Hence the name glacier, which is derived from the 

 Latin, glades ; French, glace, glacier. 



The outward appearance of glaciers is very character- 

 istically described by comparing them with Goethe to 

 currents of ice. They generally stretch from the snow- 

 fields along the depth of the valleys, filling them through- 

 out their entire breadth, and often to a considerable 

 height. They thus follow all the curvatures, windings, 

 Contractions, and enlargements of the valley. Two glaciers 

 frequently meet, the valleys of which unite. The two 

 glacial currents then join in one common principal cur- 

 rent, filling up the valley common to them both. In 

 some places these ice-currents present a tolerably level and 

 coherent surface, but they are usually traversed by cre- 

 vasses, and both over the surface and through the crevasses 

 countless small and large water rills ripple, which carry 

 off the water formed by the melting of the ice. United, 

 and forming a stream, they burst, through a vaulted arid 



