166 FORESTRY OF NORWAY. 
pressure every air-bubble had been expelled, and the 
whole mass was clear and transparent ; the cavern appeared 
like a tunnel cut through a mountain of sapphire. Un- 
fortunately I could not explore it on account of the great 
depth and velocity of the water, as it ran between two 
stone ridges, split by the ice. The retiring glacier had 
uncovered part of a spur or hill of gneiss, which had ob- 
structed its march, and which was split into several enor- 
mous parts, which were still in contact with each other. 
A considerable number of boulders were resting on the 
frozen mass, some supported on pillars of ice, which were 
prevented from melting by the protecting shade of the 
stones. In places the glacier was white, not from snow, 
but in- consequence of the cracking of its surface and 
numerous air-cells. It was easy to see that the Lodal had 
formerly been much lower down the valley, and that the 
transverse glaciers we had met on the way were once its 
lateral branches, the whole forming a single vast frozen 
river reaching the sea, retiring, advancing, again retiring. 
Thus the ice ground deeper and deeper into the rocks; the 
same marks were visible, left by that which had retired 
the year before. Iheard arumbling sound, and had hardly 
raised my eyes when a huge stone from the glacier rolled 
within a few feet of me; and I had hardly seated myself 
the second time when I saw another stone roll down car- 
rying with it in its flight several lesser ones.’ 
M. du Chaillu goes on to say: ‘A glacier is not an 
immovable mass closely attached to the mountains, but a 
body slowly impelled forward by the immense pressure of 
the upper portions. On its way the mass slides down 
grinding its rocky bed, thus deepening and enlarging its 
channel, day by day; its silent power, overcoming all 
obstacles, carries with it whatever bas been buried in the 
icy stream, such as stones that have fallen from the moun- 
tain sides, earth, and sand, which combine to render the 
water turbid, and to form the moraines. It has the charac- 
ter of a stream; it is a moving river of ice fed from the 
sneebraer or perpetual snow-fields above, modifying or creat- 
