The chasms that open in the night are even more dangerous than those of the day: their form is the reverse, Mr. Forbes informs us, of the day chasms. "They have the wider opening directed towards the base of the glacier, and terminating at its upper face, under the layer of snow which there covers the icy mass. This layer of snow falls sometimes into the chasm, but more frequently it is carried away by strong gusts of wind, which come up from the interior, and bring up an exceedingly cold air. The interior of the chasm then becomes visible, and it is found that these spacious caverns of wide dimensions are filled with piles of detached ice-blocks, tossed in chaotic heaps, whilst watery stalactitic icicles, of ten or twenty feet in length, hang from the roof, and give to these singular vaults all the grotesque varieties of outline which are so much admired in calcareous caverns, but which here shew to a far greater advantage, in consequence of their exquisite transparency and lustre, and from being illuminated, not by a few candles, but by the magical light of a tender green, which issues from the walls of the crystal chambers."
Almost all the travellers, who have been in the Alps, and have visited their glaciers, speak with rapture of their colours. "When, however, single crystals, or even small portions of the mass, are broken off, and viewed separately, they shew nothing of this colour. They are commonly white and transparent like ice, or frothy and semi-opaque. The colour appears only in the entire mass. The blue colour begins to appear gradually, and passes through all the shades from the slightest tinge to the darkest hue of the lapis lazuli. In some glaciers the blue has a mixture of green, which doubtless is to be ascribed to the prevalence of the frothy semi-opaque layers. In the lower parts of the chasms and clefts, where the ice of the glacier is in a state of dissolution by thawing, the blue colour is of a purity and beauty which can be admired, but neither described nor imitated. Where the glacier approaches the snow-mountain, the colour gets fainter, and at last passes into that of the ice of the snow-mountain, which, as above observed, is white, with a tinge of blue which is hardly perceptible."
Notwithstanding the extreme beauty of the snowy mountains and their glaciers, it is by no means desirable to live in their vicinity; as it is generally supposed that persons who drink no other water than that which flows from the melted ice and snow of the glaciers, are subject to a peculiar swelling of the glands of the throat, which is called a goitre. Modern writers deny this assertion; but it is certain the valleys are inhabited by a miserable race of beings called Cretins, who are afflicted, not only with the goitre in the throat, but with rickets which cripple and deform their bodies, and mental imbecility. It is true that in some cases, the goitre is not attended with the other symptoms of cretinism; and on the other hand, that the Cretins are often found without enlarged throats; but very generally the unhappy victims are afflicted in both manners, and the cause is now supposed to be the want of pure air. The valleys of the Alps are surrounded by very high mountains, sheltered from currents of fresh air, and exposed to the direct, and, what is worse, the reflected rays of the sun. The ground is also generally marshy, and hence the atmosphere is humid, close, and oppressive.
Avalanches are very common in the Alps. These are masses of snow or ice, which fall from the upper parts of the mountains into the valleys, and often occasion a great destruction of life and property. There are four kinds of these phenomena; viz. drift avalanches, sliding avalanches, creeping avalanches, and ice avalanches. The drift avalanches are composed of loose snow, and they only take place when a very heavy fall of snow has occurred in the higher regions during a calm. Great masses are then lodged on declivities, which are sufficient to afford a support to them during calm weather, but not when the atmosphere is agitated by strong gusts of wind. Winds of this kind detach the uppermost mass, and bring it down upon other masses, which lie lower, and which in their turn are forced off, and thus an enormous volume of snow is collected before the avalanche reaches the valley, where it always descends unexpectedly, and without any apparent cause, the gust of wind not being perceived in the deep valley. The incredible velocity with which the drift avalanches descend, and the immense force with which they strike, prove that they must have originated at a great elevation. They are very much dreaded, not so much on account of the damage caused by the snow itself, as from the effects of the compression of the air, with which they are always attended. The air compressed by these masses rushes off on all sides with the greatest velocity, and with a force able to break off huge pieces of rock, to uproot the largest trees, and to scatter houses like chaff. It is very fortunate that the drift avalanches are not of frequent occurrence, and that they rarely descend to those valleys which are thickly peopled and well wooded.
The sliding avalanches, though less destructive in their effects than the drift avalanches, cause greater damage than the others, on account of their frequency. They take place when the snowy covering of the declivities, by having been slightly thawed and again frozen, has acquired a considerable degree of consistency on its surface, and has been cemented to some extent into one mass. When, under such circumstances, by the natural heat of the earth, the bond has been loosened which unites the mass to its base, and the ground on which it rests has been rendered slippery, the whole mass begins to slide downwards in one sheet, and precipitates itself over every obstacle into the valleys. These avalanches originate in the middle regions of the mountains, on declivities which have not a very rapid slope, and in spring time. They are less dangerous because they are not attended by a compression of the air, but they cause great damage by the enormous masses of snow which they bring down. These masses are sometimes so great as to cover large extents of meadow and forest with such a thick layer of snow, that several summers must pass before it is entirely melted; and this affects the climate of the valley in a very disadvantageous way. They also frequently cause considerable loss of life and property. "In the year 1749 the whole village of Bueras, in the valley of Tavetsch, in the canton of the Grisons, was buried under, and at the same time removed from its site by, an avalanche of this description. But this change, which happened in the night-time, was effected without the least noise, so that the inhabitants were not aware of it, and on awakening in the morning could not conceive why it did not grow day. One hundred persons were dug out of the snow, sixty of whom were still alive, the hollows within the snow containing sufficient air to support life. In 1806 an avalanche descended into Val Calanca, likewise in the canton of the Grisons, transported a forest from one side of the valley to the other, and planted a fir-tree on the roof of the parsonage-house. Several villages have been destroyed by these avalanches, and a large number of persons and cattle have been killed. But in general they do not come on unexpectedly. The places where they frequently occur are known, as also what kind of weather commonly precedes their descent."
The creeping avalanches originate in the same way as the sliding avalanches, but on declivities which have a much more gentle slope. They are very frequent, but rarely cause much damage. The ice avalanches are fragments of glaciers which have become accidentally detached, and which are frequently broken into small pieces by other masses of ice, or the rocks they meet with in their progress. When seen in this state from a distance, they resemble the cataracts of a powerful stream. "In summer, which appears to be the only season in which they occur, they may every day be seen on almost all the glaciers of Switzerland; and at the base of the Jungfrau, in the valley of Lauterbrun, in the canton of Berne, the thunder which accompanies their fall is almost continually heard. They are not in general destructive, because they descend upon places which are not inhabited. Yet occasionally their fall is attended with terrible effects. This is especially the case when a glacier terminates on the very edge of a high mountain-mass, which descends with a perpendicular declivity into an inhabited valley. A very dreadful catastrophe of this kind occurred in 1819 in the valley of Visp in Valais, where the village of Randa was destroyed by a glacier avalanche. This village was built not far from the base of a mountain-mass, which rises nearly perpendicularly to an elevation of more than 9000 feet above its base, and forms part of the snow mountain called Weisshorn (white horn), which is everywhere surrounded with huge masses of glaciers. One of these glaciers had advanced to the very edge of the precipice, and was overhanging it, when at once an enormous piece of it was detached, and with a terrible crash precipitated down into the valley, where it covered with ice, rubbish, and fragments of rock, an area of 2400 feet in length, and 1000 feet wide, to a depth of more than 150 feet." The mass fell on an uninhabited tract of country adjoining the village of Randa, but the village itself was destroyed by the compression of air produced by the fall of such an enormous mass. The force of the wind was so great that millstones were raised and carried up an ascent of several yards; the beams of several houses were conveyed nearly a mile into the forest, and the steeple of the church, which was of massive stone, was snapped asunder.
Mountain slips are of almost daily occurrence in some parts of Switzerland. Sometimes they consist only of small fragments of rocks, which roll down the sides of a steep acclivity, and hurt those who are laboriously toiling up from below; but it sometimes happens that huge masses of rock, crowning the summit of very elevated peaks, descend into the contiguous lowlands, which are many thousand feet lower, and, of course, mountain slips of this kind are always attended by the most disastrous effects. Rather more than 200 years ago, a well built and pleasant town existed in Val Bregaglia, just at the foot of Mount Conto, the walls of the town being washed by the river Mera. On the 25th of August, 1618, the rainy season set in, and heavy rain continued to fall every day for nearly a week. It was observed that some large chasms in the side of the mountain increased during this heavy rain; but as the chasms had existed more than ten years, nobody paid much attention to them. On the 4th of September the weather was serene and pleasant, but in the afternoon some rubbish, composed of rocky fragments, came rolling down Mount Conto; and in the night, whilst the air was quite calm, and the sky cloudless, the summit of the mountain rushed down with a tremendous crash, and covered the whole town, burying 2430 of the inhabitants in its ruins. Only one house was left standing, and a forest of chestnut trees now grows on the remains of the mountain.
Where the cantons of Valais and the Pays de Vaud unite there is a piece of table land, "which is so elevated, that its surface is partly covered with snow and partly with glaciers." Out of this great snow-field rise the curious large pointed peaks called the Diablerets. There are now only three of these peaks but early in 1714 there were four of them. Towards the close of that year a fearful groaning was heard under the ground, the earth trembled, and when the peak fell, a thick smoke rose to a considerable height in the air. It was only dust, which was detached from the rocks when they broke to pieces. The compression of the air was so great, that some of the trees, which were near the places on which the rocks descended, were bent to the ground, or broken. Fourteen of the herdsmen were found dead, with many sheep and cattle and others were supposed to be killed, as they were missing. One man among the last was supposed to have lost his life; and his children were declared orphans by the court; but three months afterwards, on Christmas Eve, he suddenly reappeared in his native place, pale, thin, and covered with rags, resembling a spectre. All the inhabitants of the village were frightened. The doors of his own house were shut against him; and some people ran to the priest, requesting him to exorcise the supposed ghost. After some delay, the man succeeded in convincing the people that he was alive, and then he told them that in the moment on which the mountain-slip took place, he had been on his knees, praying to the Preserver of life, when an enormous fragment of rock, in descending, struck the ground before his dwelling, and resting, leant over against the rocky wall at the base of which his hut was built. It was immediately followed by a terrible crash, and by an immense quantity of stones and rubbish, entirely covering the piece of rock which protected his hut. When all became quiet, he continued, "I was no longer in fear; I did not lose my courage, and directly I set myself to work to form an opening. A few pieces of cheese, which I had in the cottage, were my food, and a rill of water, which descended among the ruins, quenched my thirst. After many days, which I was unable to count in the long darkness of my subterraneous prison, I discovered, by creeping about among the rocks, an opening; and I saw again the sun's light, but my eyes were for some time unable to bear it. The Almighty, in whom I confided, and who always kept alive my hope of preserving life, has sent me back to my family to be a witness and a proof of his power and bounty."