The avalanche is snow in quick movement towards the valleys. The glacier is snow—pressed into ice—in slow movement. A river of ice, its flow to be measured by the records of months, not of moments—that is the glacier of Alps and Polar lands. Its mission in nature is the same as that of a river, to grind down mountain rocks and to carry the detritus for the enrichment of the plains below. The glaciers of the Polar lands, coming down as they do to the edge of the ocean, are responsible for the icebergs of those seas. Compared with Polar glaciers the Alpine ones are puny, no larger, as a rule, than a large iceberg—which represents just a fragment broken off an Arctic or Antarctic glacier. But the Alpine examples of glaciers, small though they be, are grandly impressive in their natural surroundings. Such a one as the Silvretta, for instance, stretching its length for nearly twenty miles across the mountains, looks magnificently vast. From a distance a glacier seems to be white, with bands of grey, or of black from the moraines (strips of earth and stones showing on the surface). Studied at close hand it is a pageant of varied colours due to the variations of light and shade on its surface, and to the manner in which the refraction of the light is affected by the partial melting of the topmost layer of the snow. From this melting come little trickles of water which combine to form streams and then torrents. The beds of these torrents are blue in colour and like transparent glass—a lovely contrast with the general surface of the glacier. For that is made white by the innumerable fissures that penetrate its surface, fissures which are caused by the heat of the sun, from which the beds of the streams are protected. Yet more beautiful than the streams are the pools occasionally found on the surface of a glacier, when they have clean floors unsoiled by a moraine. They, too, have blue basins with white edges. Looked down upon from a distance, they appear like great sapphires. Sometimes a lake may be found not on but beside a glacier, where the ice forms one bank and the mountain another. Such are the Märjelen See by the Great Aletsch, and the lake at the west foot of Monte Rosa. On these one may see floating masses of ice. Now and again will be found crevasses filled with water, whose depth gives a yet bluer tone.
Sir Martin Conway (from whose expert study of glaciers I have freely quoted) gives the palm for glacier colouring to what is called the dry glacier.
"Note," he writes, "the brilliance of its surface and the peculiarity of its texture. It consists of an infinite multitude of loosely compacted rounded fragments of ice with a little water soaking down between them. If you watch it closely you will see that the moving water makes a shimmering in the cracks between the ice fragments. You will also observe that the blue of the solid ice below the skin of fragments appears dimly through the white, and the least tap with an ice-axe to scrape away the surface reveals it clearly. Each little fragment of ice has a separate glitter of its own, so that the whole surface sparkles with a frosted radiance. It is not the same at dawn after a cold night, for then there is no water between the fragments, but all is hard and solid. No sooner, however, does the sun shine upon them, than the bonds are released and the ice-crystals begin to break up with a gentle tinkling sound and little flashes of light reflected from tiny wet mirror-surfaces. One can spend hours watching these small phenomena as happily as gazing upon the great mountains themselves. Size is a relative term. The biggest mountain in relation to the earth is no greater than is one of these small ice-fragments in relation to a glacier. Reduce the scale in imagination and the smallest object may be endowed with grandeur, for all such conceptions are subjective. The open crevasses that are never far away on the dry glacier are full of beauties. It is not easy to tire of peering down into them. Sometimes one may be found into which a man armed with an ice-axe may effect a descent. He will not stay there long, for the depths are cold. Once I was able not only to descend into a crevasse but to follow it beyond its open part into the very substance of the glacier. It was a weird place, good to see but not good to remain in, and I was glad to return to sunshine very soon."
MÄRJELEN SEE AND GREAT ALETSCH GLACIER.
Ordinarily a glacier surface is not diversified by any large features. But sometimes peaks of rock rise as islands out of a sea of ice. Sometimes, too, inequalities in the bed of the glacier acting with the pressure of the ice mass cause great wrinklings on the surface (the Col du Géant is an instance), and from the ridges thus formed hang very beautiful ice-falls.
For the proper study of glacier beauty it is recommended to Alpine travellers that they should arrange to camp for some days in the glacier region. But there are good examples of glaciers within walking distance of some of the higher hotels.