was elevated above it, in the air, upon two pedestals, or pillars, of ice; so that a large party might have found shelter under it. A signal-post, stuck into a mass of granite, had not only made as great an advance as the hut, but the distance between it and the hut had been increased 760 feet by the expansion of the glacier. In 1839 M. Agassiz found that Hugi's cabin had advanced 4400 feet from the position it originally occupied, when first built in 1827; and, in 1840, it was 200 feet lower. The advance of the ice-field of the Mer de Glace is calculated at between 400 and 500 feet yearly, and for eight or ten years past, the mass of the glacier has been shrinking and retiring gradually.

At the extremity of almost all glaciers a high traverse ridge of rubbish, called The Terminal Moraine, exists; it consists of the fragments of rock which have fallen from the surrounding mountains, the transported débris of the Guffer, (or lateral and medial moraines), and of masses detached by the glacier itself. These are heaped up sometimes to a height of 80 or 100 feet. Not unfrequently there are 3 or 4 such ridges, one behind the other, like so many lines of intrenchment. The broken stones, mud, and sand, mixed with shattered fragments of ice, of which they are composed, have an unsightly and shabby appearance, being perfectly barren of vegetation; but each heap is, as it were, a geological cabinet, containing specimens of all the neighbouring mountains. The glacier, indeed, has a natural tendency to purge itself from impurities, and whatever happens to fall upon it is gradually discharged in this manner. It likewise exerts great mechanical force, and, like a vast millstone, grinds down not only the rock which composes its channel, but all the fragments interposed between it and the rock; forming, in the end, a sort of stone-meal. The extent of the moraine depends on the character of the strata of the mountains around the glacier: where they are of granite, or other hard rock, not easily decomposed by the weather, the moraine is of small extent; and it is largest where the boundary rocks are of brittle limestone and fissile slate. Recent researches of Swiss naturalists (Agassiz and Charpentier) have discovered extensive moraines, not only in the lower part of the Vallais, but even on the shores of the Lake Leman, at a height of not more than 200 or 300 feet above it; clearly proving that, during some anterior condition of our planet, the valley of the Rhone was occupied by glaciers, in situations at present 40 or 50 miles distant from the nearest existing ice-field, and 3000 or 4000 feet below it.

It is highly interesting to consider how important a service the glaciers perform in the economy of nature. These dead and chilly fields of ice, which prolong the reign of winter throughout the year, are, in reality, the source of life and the springs of vegetation. They are the locked-up reservoirs, the sealed fountains, from which the vast rivers traversing the great continents of our globe are sustained. The summer heat, which dries up other sources of water, first opens out their bountiful supplies. When the rivers of the plain begin to shrink and dwindle within their parched beds, the

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torrents of the Alps, fed by melting snow and glaciers, rush down from the mountains and supply the deficiency; and, at that season, (July and August), the rivers and lakes of Switzerland are fullest. During the whole summer, the traveller who crosses the glaciers hears the torrents rustling and running below him at the bottom of the azure clefts. These plenteous rills gushing forth in their subglacial beds, are generally all collected in one stream, at the foot of the glacier, which, in consequence, is eaten away into a vast domeshaped arch, sometimes 100 feet high, gradually increasing until the constant thawing weakens its support, and it gives way and falls in with a crash. Such caverns of ice are seen in great perfection in some years, at the source of the Arveyron, in the valley of Chamouni, and in the glaciers of Grindelwald. The streams issuing from glaciers are distinguished by their turbid, dirty-white, or milky colour.

18. AVALANCHES AND SNOW-STORMS.

"The avalanche, the thunderbolt of snow."-Byron.

Avalanches (Germ. Lawinen) are those accumulations of snow which precipitate themselves from the mountains, either by their own weight or by the loosening effects of the sun's heat, into the valleys below, sweeping everything before them, and causing, at times, great destruction of life and property. The fearful crash which accompanies their descent is often heard at a distance of several leagues.

The natives of the Alps distinguish between several different kinds of avalanches. The staub-lawinen (dust avalanches) are formed of loose fresh-fallen snow, heaped up by the wind early in the winter, before it has begun to melt or combine together. Such a mass, when it reaches the edge of a cliff or declivity, tumbles from point to point, increasing in quantity as well as in impetus every instant, and spreading itself over a wide extent of surface. It descends with the rapidity of lightning, and has been known to rush down a distance of 10 miles from the point whence it was first detached; not only descending one side of a valley, but also ascending the opposite hill, by the velocity acquired in its fall, overwhelming and laying prostrate a whole forest of firs in its descent, and breaking down another forest, up the opposite side, so as to lay the heads of the trees up the hill in its ascent.

Another kind of avala nche, the grund lawinen, occurs in spring, during the months of April and May, when the sun becomes powerful and the snow thaws rapidly under its influence. They fall constantly from different parts of the mountains, at different hours of the day, accordi ng as each part is reached by the sun: from the E. side between 10 and 12, from the S. side between 12 and 2, and later in the day from the W. and N. This species is more dangerous in its effects, from the snow being clammy and adhesive, as well as hard and compact. Any object buried by it

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can only be dug out by the most arduous labour. Men or cattle overwhelmed by the staub-lawine can sometimes extricate themselves by their own exertions; or, at any rate, from the snow being less compact, may breathe for some hours through the interstices. In the case of the grund-lawine, the sufferers are usually either crushed or suffocated, and are, at any rate, so entangled that they can only be rescued by the aid of others. Such avalanches falling upon a mountain-stream, in a narrow gorge, have sometimes been hollowed out from beneath by the action of the water, until it has forced a passage under them; and they have then been left standing for the whole summer, serving as a bridge over which men and cattle might pass.

The avalanches have usually a fixed time for descending, and an habitual channel down which they slide, which may be known by its being worn perfectly smooth sometimes even appearing polished, by the heap of debris at its base. The peasants, in some situations, await with impatience the fall of the regular avalanches, as a symptom of the spring having fairly set in.

Danger arises from avalanches either by their falling unexpectedly, while persons are traversing spots known to be exposed to them, or else (and this is the more fearful source of catastrophes) from an unusual accumulation of snow raised by the wind, or, in consequence of the severity of the season, causing the avalanche to desert its usual bed, and to descend upon cultivated spots, houses, or even villages. There are certain valleys among the Alps in which scarcely any spot is totally exempt from the possible occurrence of such a calamity, though some are naturally more exposed than others. The Val Bedretto, in canton Tessin, the Meyenthal, in canton Uri, and many others, are thus dreadfully exposed. To guard as much as possible against accidents, very large and massive dykes of masonry, like the projecting bastions of a fortification, are in such situations, built against the hill-side, behind churches, houses, and other buildings, with an angle pointing upwards, in order to break and turn aside the snow. In some valleys, great care is bestowed on the preservation of the forests clothing their sides, as the best protection of the district below them from such calamities. These may truly be regarded as sacred groves; and no one is allowed to cut down timber within them, under pain of a legal penalty. Yet they not unfrequently show the inefficiency even of such protection against so fearful an engine of destruction. Whole forests are at times cut over and laid prostrate by the avalanche. The tallest stems, fit to make masts for a first-rate manof-war, are snapped asunder like a bit of wax, and the barkless and branchless stumps and relics of the forest remain for years like a stubble-field to tell of what has happened.

A mournful catalogue of catastrophes, which have occurred in Switzerland, since the records of history, from avalanches, might be made out if necessary; but it will suffice to mention one or two instances.

In 1720 an avalanche killed, in Ober-Gestelen (Vallais), 84 men

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and 400 head of cattle, and destroyed 120 houses. The same year, 40 individuals perished at Brieg, and 23 on the Great St. Bernard, from a similar cause.

In 1749 the village of Ruaras, in the Tavetsch Thal, was carried away by an avalanche; 100 men were overwhelmed by it, 60 of whom were dug out alive; and several of the houses, though removed to some distance from their original site, were so little shaken that persons sleeping within them were not awakened.

In 1800, after a snow-storm of three days' continuance, an enormous avalanche detached itself from the top of the precipice of Klucas above Trons, in the valley of the Vorder Rhein; it crossed the valley and destroyed a wood and some chalets on the opposite pasture of Zenin; recoiling, with the force it had acquired, to the side from which it had come, it did fresh mischief there, and so revolving to and fro, at the fourth rush reached Trons, and buried many of its houses to the roof in snow.

In 1827 the greater part of the village of Biel, in the Upper Vallais, was crushed beneath a tremendous avalanche, which ran down a ravine, nearly two leagues long, before it reached the village.

One of the most remarkable phenomena attending the avalanche is the blast of air which accompanies it, and which, like what is called the wind of a cannon-ball, extends its destructive influence to a considerable distance on each side of the actual line taken by the falling mass. It has all the effect of a blast of gunpowder: sometimes forest-trees, growing near the sides of the channel down which the snow passes, are uprooted and laid prostrate, without having been touched by it. In this way, the village of Randa, in the Visp-Thal, lost many of its houses by the current of an avalanche which fell in 1720, blowing them to atoms, and scattering the materials like chaff. The E. spire of the convent of Dissentis was thrown down by the gust of an avalanche, which fell more than a quarter of a mile off.

Travellers visiting the Alps between the months of June and October are little exposed to danger from avalanches, except immediately after a snow-storm; and, when compelled to start at such times, they should pay implicit obedience to the advice of the guides. It is a common saying, that there is risk of avalanches as long as the burden of snow continues on the boughs of the fir-trees, and while the naturally sharp angles of the distant mountains continue to look rounded.

It is different with those who travel from necessity in the spring, and before the annual avalanches have fallen. Muleteers, carriers, and such persons, use great caution in traversing exposed parts of the road, and with these they are well acquainted. They proceed, in parties, in single file, at a little distance from one another, in order that, if the snow should sweep one off, the others may be ready to render assistance. They proceed as fast as possible, carefully avoiding any noise, even speaking, and, it is said, will sometimes muffle the mules' bells, lest the slightest vibration communicated to the air should disengage the nicely-poised mass of snow above their heads.

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The avalanches, seen and heard by summer tourists on the sides of Mont Blanc and the Jungfrau, are of a different kind from those described above, being caused only by the rupture of a portion of the glaciers, which give way under the influence of the mid-day sun and of certain winds, during the summer and autumn, when other avalanches, generally speaking, have ceased to fall. They differ, also, in this respect, that, for the most part, they do no harm, since they fall on uncultivable and uninhabited spots. It is more by the roar which accompanies them, which, awakening the echoes of the Alps, sounds very like thunder, than by the appearance which they present, that they realize what is usually expected of avalanches. Still they are worth seeing, and will much enhance the interest of a visit to the Wengern Alp, the Cramont (on the S. side of Mont Blanc), or the borders of the Mer de Glace; especially if the spectator will bear in mind the immense distance at which he is placed from the objects which he sees and hears, and will consider that, at each roar, whole tons of solid ice are broken off from the parent glacier, and, in tumbling, many hundred feet, perhaps, are shattered to atoms and ground to powder.

The Snow-storms, Tourmentes, or Guxen, which occur on the Alps, are much dreaded by the chamois-hunter, the shepherd, and those most accustomed to traverse the High Alps; how much more formidable must they be to the inexperienced traveller! They consist of furious and tempestuous winds, somewhat of the nature of a whirlwind, which occur on the summit-ridges and elevated gorges of the Alps, either accompanied by snow, or filling the air with that recently fallen, while the flakes are still dry, tossing them about like powder or dust. In an instant the atmosphere is filled with snow; earth, sky, mountain, abyss, and landmark of every kind, are obliterated from view, as though a curtain were let down on all sides of the wanderer. All trace of path, or of the footsteps of preceding travellers, are at once effaced, and the poles planted to mark the direction of the road are frequently overturned. In some places the gusts sweep the rock bare of snow, heaping it up in others, perhaps across the path, to a height of 20 feet or more, barring all passage, and driving the wayfarer to despair. At every step he fears to plunge into an abyss, or sink overhead in the snow. Large parties of men and animals have been overwhelmed by the snow-wreaths on the St. Gothard, where they sometimes attain a height of 40 or 50 feet. These tempests are accompanied almost every year by loss of life; and, though of less frequent occurrence in summer than in winter and spring, are a chief reason why it is dangerous for inexperienced travellers to attempt to cross remote and elevated passes without a guide.

The guides and persons residing on the mountain-passes, from the appearance of the sky, and other weather-signs known to them, can generally foresee the occurrence of tourmentes, and can tell when the fall of avalanches is to be apprehended.