over and falls down. This is one evidence that the glaciers move.

But there is another proof that the ice of the glaciers is continually
moving onward which is still more direct and decisive. Certain
philosophers, who wished to ascertain positively what the truth was,
went to a glacier, and, selecting a large rock which lay upon the
surface of it near the middle of the ice, they made a red mark with
paint upon the rock, and two other marks on the rocks which formed the
shore of the glacier. They made these three marks exactly in a line with
each other, expecting that, if the glacier moved, the rock in the centre
of it would be carried forward, and the three marks would be no longer
in a line.

This proved to be the case. In a very short time the central rock was
found to have moved forward very perceptibly. This was several years
ago. This rock is still on the glacier; and the red mark on it, as well
as those on the shores, still remains. All the travellers who visit the
glacier look at these marks and observe how the great rock on the ice
moves forward. It is now at a long distance below the place where it was
when its position was first recorded.

Then, besides, you can actually hear the glaciers moving when you stand
upon them. It is sometimes very difficult to get upon them; for at the
sides where the ice rubs against the rocks, immense chasms and fissures
are formed, and vast blocks both of rock and ice are tumbled confusedly
together in such a manner as to make the way almost impracticable. When,
however, you fairly get upon the ice, if you stand still a moment and
listen, you hear a peculiar groaning sound in the _moraines_. To
understand this, however, I must first explain what a moraine is. On
each side of the glacier, quite near the shore, there is usually found a
ridge of rocks and stones extending up and down the glacier for the
whole length of it, as if an immense wall formed of blocks of granite of
prodigious magnitude had been built by giants to fence the glacier in,
and had afterwards been shaken down by an earthquake, so as to leave
only a confused and shapeless ridge of rocks and stones. These long
lines of wall-like ruins may be traced along the borders of the glacier
as far as the eye can reach. They lie just on the edge of the ice, and
follow all the bends and sinuosities of the shore. It is a mystery how
they are formed. All that is known, or rather all that can be here
explained, is, that they