146 SCENERY OF SWITZERLAND. 
It is 15 miles in length and covers 50 square miles. 
It commences with a great snow sheet, the Grosse 
Aletsch Firn, the lower or N.W. end of which is 
known as the Concordia Platz. From this immense 
central snow-field radiate the Jungfrau Firn to the 
N.W., the Ewigschneefeld to the north, and the 
Aletsch glacier to the S.E. The view from the 
Grosse Grtinhorn is peculiarly arctic, for though it 
is very extensive, scarcely any trace of green is 
visible. 
The Maijelen Thai falls in about the centre of the 
Aletsch glacier on the south side. If there were no 
glacier, the stream from this valley would join that 
of the Aletsch valley. The Aletsch glacier, however, 
occupies the great valley, and dams back the water 
of the lateral stream. The side of the glacier forms 
a cliff, 1 50 feet in height, and rising some 50 feet 
above the level of the Marjelen See. From this cliff 
great masses are detached from time to time, which 
float as miniature icebergs in the lake. 
To prevent the water from rising too high a 
channel has been dug, which carries off the surplus 
down to Viesch. Every few years, however, some 
change in the glacier lets out the lake, which rushes 
under the ice down the Massa valley. The Maijelen 
See is quite unique. The pure white of the icebergs, 
