our temporary
winters--in fact, whenever the snow falls the earth it covers enters
upon an ice period which differs only in degree from that from which
our hemisphere is just escaping.

Where the reader is so fortunate as to be able to visit a region of
glaciers, he had best begin his study of their majestic phenomena by
ascending to those upper realms where the snow accumulates from year
to year. He will there find the natural irregularities of the rock
surface in a measure evened over by a vast sheet of snow, from which
only the summits of the greater mountains rise. He may soon satisfy
himself that this sheet is of great depth, for here and there it is
intersected by profound crevices. If the visit is made in the season
when snow falls, which is commonly during most of the year, he may
observe, as before noted in our winter's snow, that the deposit,
though at first flaky, attains at a short distance below the surface a
somewhat granular character, though the shotlike grains fall apart
when disturbed. Yet deeper, ordinarily a few feet below the surface,
these granules are more or less cemented together; the mass thus loses
the quality of snow, and begins to appear like a whitish ice. Looking
down one of the crevices, where the light penetrates to the depth of a
hundred feet or more, he may see that the bluish hue somewhat
increases with the depth. A trace of this colour is often visible even
in the surface snow on the glacier, and sometimes also in our ordinary
winter fields. In a hole made with a stick a foot or more in depth a
faint cerulean glimmer may generally be discerned; but the increased
blueness of the ice as we go down is conspicuous, and readily leads us
to the conclusion that the air, to which, as we before noted, the
whiteness of the snow is due, is working out of the mass as the
process of compaction goes on. In a glacial district this snow mass
above the melting line is called the _neve_.

Remembering that the excess of snow beyond the melting in a _neve_
district amounts, it may be, to some feet of material each year, we
easily come to the conclusion that the mass works down the slope in
the manner which it does even where the coating is impermanent. This
supposition is easily confirmed: by observing the field we find that
the sheet is everywhere drawing away from the cliffs, leaving a deep
fissure between the _neve_ and the precipices. This crevice is called
by the German-Swiss guides the _Bergschr