The prison mirror. [volume] (Stillwater, Minn.) 1887-1894, 1890-12-25
REPORT FOR CLASS G..
THE GLACIER.

The GI.ACIER.
LIST. Dehnition.-A Glacier is a mass of ice. hav-
ing its origin in the hollOws Of mountains where
perpetual snow accumulates, which makes its way
down towards the lower vale. where it gradually
melts.
End. How FOrmed.-Winter snow under the
zion of alternate freezing and thawing becomes
granulated as Is often observed in the spring. in
the old snow of the previous winter. In high
mountains broad fields Of granular snow comes
into existence, and at certain elevations the aver
age annual temperature. is not sufficient to melt it
before the next autumnal SHOWS begin to increase
the amount. This point is called the line of per-
petual snow, and depends good deal upon the
temperature of the summer as Baron Humboldt
first discoveries it is usually about 1000 feet above
sea level These granular fields Of snow are
known as firm. or neve and extending as they do
down the mountain valleys. and being exposed to
increased warmth, are completely changed into
solid ice thus forming the glacier.
3rd. Movement ALI parts of the glacier move
continually downward The amount of motion
depends to a certain extent. upon the collection
of snow back of it, and upon the slope OF its bed
and the motion varies from $50 to 800 feet per
annum. The alternate contraction and expansion
in connection with its motion causes great crew
~oSSS
to many hundreds of feet in extent. These, being
often covered by avalanches of snow from the
higher mountains forming sort of roof over the
crevasses, constitute of the greatest dangers of
mountain climbing. The earthly matter, and
rocky rubbish carried along in its movement is
termed moraine. Lying in front of the lower end
of glacier it marks the greatest limit of extern.
sion which it has at any time attained Some
times il ia IN hava wit Co..
its old limits leaving extensive barren waste of
stone. Again it will push forward its margin be-
yond its hitherto limits tearing up the earth up
roofing trees. displacng or carrying along large
rocks,causing ruin and desolation to everything IN
its path.
4th. Appearance.-The lower end is usually steep,
frequently broken up into intersecting cracks and
the constant action of the snow and rain sharpens
1t into pyramids at once grotesque and beautiful
The walls of the crevasses. resemble delicate
vened marble varying in shade from bluish-green
through green to white. The tremendous MASKING
together which it experiences through the M owe.
ments of its flow squeeze pyramids and huge col
umns 10, 20 and even 40 feet above the general
surface. On the even slopes we find eternal cos.
cades the surface water collecting In considerable
quantity by long course of flowing over its surface
are precipitated with violence into the first assure
fmeets with. The descending water keeps open
a channel which finally loses its form of issurs
presents that of en- open shaft of great depth De-
saussure. probably. gives the best description of
the appearance of the glacier. when he says, tn at
1t resembles sea which has become suddenly
frozen, not during a.tempest. but at the instant
when the wind has subsidized and the waves, al
though very high, have become blunted and
rounded. The best known glaciers are those of the
Alps in the Chamouni Valley of Switzerland
among which are Glacier de Tacounay. Glac er des
Bossous, Mer de Glace and Glacier de Lechaud and
Glacier du Tour. In America the two most fire.
quently spoken of by travellers are the Konwakton
Glacier, Of Mt. Shasta Cal. and the Muir Glacier
of Alaska.
The Necessity Of CheerfluIness