g into them, in great avalanches, in the spring.
These vast depositories of snow become changed into ice below the
surface; for at the surface there is a continual melting, and the
water, flowing down through the mass, freezes below. Thus there are
valleys, or rather ravines, some of them two or three miles wide and
ten or fifteen miles long, filled with ice, transparent, solid, and
blue, hundreds of feet in depth. They are called _glaciers_. And what
is most astonishing in respect to these icy accumulations is that,
though the ice is perfectly compact and solid, the whole mass is found
to be continually in a state of slow motion down the valley in which
it lies, at the rate of about a foot in twenty-four hours. By standing
upon the surface and listening attentively, we hear, from time to
time, a grinding sound. The rocks which lie along the sides are
pulverized, and are continually moving against each other and falling;
and then, besides, which is a more direct and positive proof still of
the motion of the mass, a mark may be set up upon the ice, as has been
often done, and marks corresponding to it made upon the solid rocks on
each side of the valley, and by this means the fact of the motion, and
the exact rate of it, may be fully ascertained.

Thus these valleys are really and literally rivers of ice, rising
among the summits of the mountains, and flowing, slowly it is true,
but with a continuous and certain current, to a sort of mouth in some
great and open valley below. Here the streams which have flowed over
the surface above, and descended into the mass through countless
crevices and chasms, into which the traveler looks down with terror,
concentrate and issue from under the ice in a turbid torrent, which
comes out from a vast archway made by the falling in of masses which
the water has undermined. This lower end of the glacier sometimes
presents a perpendicular wall hundreds of feet in height; sometimes it
crowds down into the fertile valley, advancing in some unusually cold
summer into the cultivated country, where, as it slowly moves on, it
plows up the ground, carries away the orchards and fields, and even
drives the inhabitants from the villages which it threatens. If the
next summer proves warm, the terrible monster slowly draws back its
frigid head, and the inhabitants return to the ground it reluctantly
evacuates, and attempt to repair the damage it has done.

The Alps lie between France and Italy, and t