Glaciers. 201 



to the end of the glacier, to be dropped with 

 the other debris that has been carried there by 

 the same force, forming an accumulation that 

 geologists call the "moraine." Of these mo- 

 raines we will speak more fully later on. 



It was the privilege of the writer some years 

 since to visit the great glaciers of Switzerland 

 and to some extent study their action. Some 

 rivers have their origin chiefly in melting 

 glaciers. They start as ice rivers and end in 

 rivers of water. The effects during the great 

 ice age of some of these glacial rivers, which 

 are now extinct, are very remarkable; we shall 

 have occasion to refer to them when we come 

 to treat of the glacial period. 



There is a glacial river flowing which is fed 

 largely by the great Rhone glacier in Switzer- 

 land. The water from this river is almost as 

 white as milk, which is occasioned by the 

 grinding action of the great ice blocks on the 

 rock as it flows down the sides of the moun- 

 tain. These glacial rivers are much higher in 

 summer, of course, than in winter, some of 

 them having not only an annual fluctuation, 

 but a diurnal one. The former is caused by 

 the cold of winter, and the latter because it- 

 freezes to some extent at night and checks the 

 flow of water. The difference between day and 

 night in these high altitudes is very marked. 

 While it is extremely hot in the sun, it is cool 

 the moment we step into the shade. 



