Mountains help to cause movement and change in the atmosphere. Let us see how this takes place. Mountains expose on one side their masses of rock to the full heat of the sun. Rocks are capable of becoming highly heated under a blazing sun: we have known stone walls, even in England, to be almost too hot to touch; and perhaps the reader may have often noticed the quivering of the hot air as it rises from the ground on a summer day, especially over a road or any piece of bare rocky ground. This quivering tells us that the air is highly heated by the ground beneath, and is consequently rising. You know how the pebbles look beneath a clear running stream; and the things which we see through air in this state all seem to be similarly moving or quivering. It is easy then to imagine how masses of heated air would rise up from the side of a mountain-range which faces the sun,—that is, the southern side,—while on the other, or northern side they cast a soft shadow for leagues over the plains at their feet. In this way mountains divide a district into two different climates, with a light warm air on their southern slopes, and colder air on the northern, and the rising of the warm air will cause a certain amount of circulation and movement. Hence mountains help to make currents in the atmosphere, and these currents produce important consequences.

When mountain-ranges trend more or less directly across the direction of prevailing winds, they always have a moist side and a dry one. In the torrid zone, where easterly winds prevail, the eastern slope is usually the moist side; but in higher latitudes, as, for example, in Europe, the western side of mountain-ranges receives the greatest amount of rainfall, because westerly winds prevail there.

Mountains are barriers dividing not only one nation from another, but separating also various tribes of plants and animals. It will be readily understood that with the exception of birds, whose powers of flight render them independent of physical barriers, most animals find mountains more impassable than men do. We can make roads and railways, but they cannot thus aid their powers of locomotion; hence mountains put limits to their migrations. Still, climate and food supplies have a greater influence in determining the boundaries of zoölogical provinces (see chapter iv.).

Mountains are the backbones of continents. A glance at a map of the world will show that there is evidently a close connection between continents and great mountain-chains. This connection shows itself both in the shapes and general direction of continents. Thus, the long continuous line of mountain-chain which extends from the southern spur of the Andes to the northern end of the Rocky Mountains,—a distance of about nine thousand miles,—corresponds with the general trend of the North American continent, and forms the axis or backbone of that vast tract of land. It seems as if the sea on its western side were kept at bay by this great rocky wall, while on its eastern side the rivers have formed new land. A line of mountains is often the coast line, for the sea cannot overcome it unless subsidence takes place. The backbone of Asia and Europe runs east and west, and the continental area of the Old World follows the same general direction.

These are the chief uses of mountains, and the facts which we have brought forward will serve to show how indispensable they are. The following eloquent passage from "Modern Painters" may form a fitting close to the present chapter:—

"And thus those desolate and threatening ranges which in nearly all ages of the world men have looked upon with aversion or with horror, and shrunk back from as if they were haunted by perpetual images of death, are in reality sources of life and happiness, far fuller and more beneficent than all the bright fruitfulness of the plain. The valleys only feed; the mountains feed and guard and strengthen us. We take our ideas of fearfulness and sublimity alternately from the mountains and the sea; but we associate them unjustly. The sea-wave, with all its beneficence, is yet devouring and terrible; but the silent wave of the blue mountain is lifted towards heaven in a stillness of perpetual mercy; and the one surge, unfathomable in its darkness, the other unshaken in its faithfulness, for ever bear the seal of their appointed symbolism:—

CHAPTER III.
SUNSHINE AND STORM ON THE MOUNTAINS.

"The spirit of the hills is action, that of the lowlands repose."[9] The plains, with their peaceful meadows and meandering streams, might almost be said to be asleep; but the mountains are wide awake. They are emphatically scenes of violent or rapid action. The wind blows more fiercely among the mountain-peaks than over the plains below; heat and cold are more extreme; and every process of change or decay seems quickened.

Avalanches, falls of rock, earthquakes, storms, and floods exhibit the more terrible aspects of the hills. Yet they have their gentler moods: witness the brightness of the starry sky overhead, and its intense blue by day, the wonderful sunrises and sunsets, the lovely effects of light and shade, of cloud and mist, the stillness and silence of the eternal snows in summer, and the beauty of the Alpine flower.

Let us see what those who know mountains best have to say about the wonderful things they have seen there. To begin with sunset and sunrise. Professor Bonney remarks,—

"Not the least interesting peculiarity of an Alpine sunset is the frequency with which its most beautiful effects are revealed quite unexpectedly. Often at the close of a rainy afternoon, the clouds, just before the sun goes down, break, roll up, sometimes disperse as if by magic, in the glory of those crimson rays that come darting upon them and piercing every rift. Many a time have I watched the vapours around a mountain-peak curling lightly upwards, and melting away into the sky, till at last the unclouded summit glowed with flushes of orange and rose, ere it grew pale and dead in its shroud of fresh-fallen snow."[10]

Here is a description by Professor Tyndall of a sunset witnessed in the neighbourhood of the Weisshorn:—

"As the day approached its end, the scene assumed the most sublime aspect. All the lower portions of the mountains were deeply shaded, while the loftiest peaks, ranged upon a semicircle, were fully exposed to the sinking sun. They seemed pyramids of solid fire; while here and there long stretches of crimson light drawn over the higher snowfields linked the glorified summits together. An intensely illuminated geranium flower seems to swim in its own colour, which apparently surrounds the petals like a layer, and defeats by its lustre any attempt of the eye to seize upon the sharp outline of the leaves. A similar effect has been observed upon the mountains; the glory did not seem to come from them alone, but seemed also effluent from the air around them. This gave them a certain buoyancy which suggested entire detachment from the earth. They swam in splendour which intoxicated the soul; and I will not now repeat in my moments of soberness the extravagant analogies which ran through my brain. As the evening advanced, the eastern heavens low down assumed a deep purple hue, above which, and blended with it by infinitesimal gradations, was a belt of red, and over this again zones of orange and violet. I walked round the corner of the mountain at sunset, and found the western sky glowing with a more transparent crimson than that which overspread the east. The crown of the Weisshorn was embedded in this magnificent light. After sunset the purple of the east changed to a deep neutral tint; and against the faded red which spread above it, the sun-forsaken mountains laid their cold and ghostly heads. The ruddy colour vanished more and more; the stars strengthened in lustre, until finally the moon and they held undisputed possession of the blue-grey sky."[11]

Marvellous sunsets are to be witnessed from the mountains of the New World. The following is a short and graphic description of sunset glories on the Sierra Nevada Mountains by Mr. Clarence King, whose name is well known to geologists:—

"While I looked, the sun descended, shadows climbed the Sierras, casting a gloom over foothill and pine, until at last only the snow summits, reflecting the evening light, glowed like red lamps along the mountain-wall for hundreds of miles. The rest of the Sierra became invisible. The snow burned for a moment in the violet sky, and at last went out."

These marvellous effects appeal powerfully to our sense of beauty and produce in most minds feelings of intense delight; but they also appeal to the reasoning faculty in man, and an intelligent observer naturally inquires, "Why are these things so? How are those glorious colours of crimson, orange, and yellow produced?" A full explanation cannot be attempted here; but this much may perhaps be said without tiring the patience of the reader. White light, such as sunlight or the light from an electric arc, is composed of all the colours of the rainbow,—violet, indigo, blue, green, yellow, orange, and red. A ray of sunlight on passing through a prism is split up into all these colours in the above order, and we get them arranged in a band which is known as the spectrum. Thus it is proved that white light is made up of all colours (black is not a colour, but the absence of colour). Now, when the sun is low down in the sky, as at sunset, only some of these colour-rays are able to pass through the atmosphere and so to reach our eyes, while others are stopped in passing through very many miles of atmosphere (as they must obviously do when the sun is low). Those which are stopped are the blue rays and others allied to blue, such as purple and green; but the red and yellow rays are able to pass on till they come to us. Hence red, yellow, and orange are the prevailing sunset tints.

What, then, becomes of the missing blue rays? They are caught by the myriads of little floating particles in the air, and reflected away from us. That is why we do not see them; their course is turned back, just as waves breaking against a stone sea-wall are turned back or reflected. A person situated behind such a wall will not see the waves which break against it; but suppose a very big wave came: it would come right over, and then we should soon become aware of its presence. So it is with the little waves of light: some are stopped and turned back as they break against the myriads of little dust particles and the still more numerous particles of mist always floating in the air; while others, which are larger, break over them and travel on undisturbed until they reach our eyes. Now, the larger waves of light are the red waves, while the smaller ones are the blue waves; hence there is no difficulty in understanding why the red waves (or vibrations) are seen at sunset and sunrise, to the exclusion of the blue waves. But it must be borne in mind that light-waves are of infinitesimal smallness, thousands and thousands of them going to make up an inch. Sound also travels in waves, and the phenomena of sound serve to illustrate those of light; but sound-waves are very much larger.

The reason why the sky overhead appears blue is that we see the blue rays reflected down to the earth from myriads of tiny dust and water particles, while the red rays pass on over our heads, which is just the reverse of what happens at sunset.

On the southern slopes of the Alps the blues of the sky are generally very different from those on the northern side; and this is probably due to the greater quantity of water-vapour in the air, for the moist winds come from the south. Sunrises in the Alps are quite as glorious to behold as sunsets; but comparatively few people rise early enough to see them. Speaking generally, it may be said that in Alpine sunrises the prevailing colours are orange and gold, in sunsets crimson or violet-pink. After a cool night the atmospheric conditions will obviously be different from those which exist after a warm day, and more water-vapour will have been condensed into mist or cloud. Hence we should expect a somewhat different effect.

The snowfields on high ranges of mountains are of a dazzling whiteness; and their bright glare is so great as to distress the eyes of those who walk over them without blue glasses, and even to cause inflammation. At these heights the traveller is not only exposed to the direct rays of the sun, untempered save for a thin veil of rarefied air, but also to an intense glare produced by the little snow-crystals which scatter around the beams of light falling upon them. Scientific men, who have studied these matters, say that the scorching of the skin and "sun-burning" experienced by Alpine travellers is not caused, as might be supposed, by the heat of the sun, but by the rays of light darting and flashing on all sides from myriads of tiny snow-crystals.

Occasionally a soft lambent glow has been observed on snowfields at night. This is a very curious phenomenon, to which the name of "phosphorescence" has, rightly or wrongly, been given. A pale light may often be seen on the sea during a summer night, when the water is disturbed in any way; and if one is rowing in a boat, the oars seem glowing with a faint and beautiful light. It is well known that this is caused by myriads of little light-producing animalcules in the sea-water. But we can hardly suppose that the glow above referred to is produced by a similar cause. One observer says the glow is "something like that produced by the flame of naphtha;" and he goes on to say that at every step "an illuminated circle or nimbus about two inches in breadth surrounded our feet, and we seemed to be ploughing our way through fields of light, and raising clods of it, if I may be allowed the expression, in our progress." Another observer, also an Alpine traveller, says that at almost every footstep the snowy particles, which his companion in front lifted with his feet from the freshly fallen snow, fell in little luminous showers. The exact cause which produces this strange effect at night has not been ascertained.

There is another curious phenomenon often seen just before sunset on a mountain in Hungary. It is known as "The Spectre of the Brocken." The Brocken is the highest summit of the Hartz Mountains. As you step out upon the plateau upon the top of the hill, your shadow, grim and gigantic, is apparently flung right out against the eastern sky, where it flits from place to place, following your every movement. The explanation is simply this: to the east of the Hartz Mountains there is always a very dense and hazy atmosphere, so dense that it presents a surface capable of receiving the impression of a shadow, and of retaining it, as a wall does. The shadows are really close at hand, not a long way off, as might at first sight be supposed. If very far away, they would be too faint to be visible.

In all mountainous regions the permanent habitations of men cease at a limit far below the most elevated points reached by the mountain-climber. St. Veran and Gargl, the highest villages of France and Germany, are situated at the respective heights of 6,591 and 6,197 feet; but the Hospice of St. Bernard, in Switzerland, built centuries ago to shelter travellers when benumbed with the cold, is much more elevated, its height being 8,110 feet above sea-level. The most elevated cluster of houses in the world is the convent of Hanle, inhabited by twenty Thibetan priests; its height is 14,976 feet. None of the villages of the Andes, except perhaps that of Santa Anna, in Bolivia, have been built at so great a height.

Travellers who venture to ascend lofty mountains not only have to suffer all the rigours of cold and run the risk of being frozen on their route, but they may also experience painful sensations owing to the rarefaction of the air. It would naturally be supposed that at an elevation at which the pressure of the atmosphere is reduced to one half, or even to one fourth that of the plains below, a certain uneasiness should be caused by the change, the more so since other conditions, such as warmth and moisture, are different. Undaunted climbers, like Professor Tyndall, who have never felt the effect of this "mountain-sickness" (mal de montagne), deny that the sensations proceed from anything else than mere fatigue. In the Himalayas, the traveller does not begin to suffer from the attacks of this ailment until he has reached a height of 16,500 feet; while on the Andes a large number of persons are affected by it at an altitude of 10,700 feet. In the South American mountains, the symptoms are much more serious: to the fatigue, head-ache, and want of breath are added giddiness, sometimes fainting-fits, and bleeding from lips, gums, and eyelids. The aeronaut, however, who is spared all the fatigue of climbing, rarely suffers any inconvenience except from cold, at such elevations. But on rising to greater heights, 30,000 or 40,000 feet, the malady shows itself; and if the balloon continued to rise, the aerial voyager would infallibly perish.

Professor Bonney says:—

"I have occasionally seen persons singularly affected on high mountains; and as the barometer stands at about sixteen inches on Mont Blanc, and at thirty at sea-level, one would expect this great difference to be felt. Still, I do not think it easy to separate the inconveniences due to atmosphere from those caused by unwonted fatigue, and am inclined to attribute most of them to the latter."

But the fact that the aeronaut suffers seems conclusive.

The violent storms which break upon mountain districts often cause floods of considerable magnitude, such as may be compared with the memorable bursting of the Holmfirth reservoir. Hardly a year passes without considerable damage being done: bridges are swept away; roads are buried under torrents of mud, and fields overwhelmed with débris. In August of the year 1860 a severe storm was witnessed by visitors staying at Zermatt. It began with a thunder-storm; and rain fell for about thirty-six hours, after which, as may be supposed, the torrents were swollen far beyond their usual size. Lower down in the valleys much harm was done, but there one bridge only was swept away. It was, however, an awful sight to see the Visp roaring under one of the bridges that remained, and to hear the heavy thuds of the boulders that were being hurried on and dashed against one another by the torrent.

In September, 1556, the town of Locarno, in the Canton Ticino, was visited by a destructive storm and flood. The day began by several shocks of earthquake, followed, about five o'clock, by a terrific gale from the south. Part of the old castle was blown down; the doors of St. Victor's Church were burst open by a blast while the priest was at the altar; and everything within was overturned. At midday the clouds were so thick that it was almost as dark as night. A violent thunder-storm and torrents of rain followed, lasting from two to six o'clock in the evening. The rivulets all became torrents; the stream flowing through the town was so choked by uprooted trees and rocks that its water flooded the streets and almost buried them under mud and gravel. Such a sight as this gives one a powerful impression of the geological work of streams when greatly swollen; for all this débris must have been brought down from the surrounding mountains. Many lives were lost by this calamity, and a great deal of property was destroyed. Late in the year, during unsettled weather, the traveller often encounters on Alpine passes a sudden storm of snow, accompanied by violent gusts of wind, which fill the air with drifted flakes; so that becoming bewildered, he loses his way, and at last sinks down benumbed with cold and dies. Many a frequented pass in Switzerland has been the scene of death from this cause. Exhausted with fatigue, and overcome with cold, the traveller sinks down by the wayside, and the guides, after having in vain endeavoured to urge him on, are compelled, in order to save their own lives, to leave him to his fate and press forward. The name "Tourmente" is given to these storms.

On the tops of the highest mountains, even in very fine weather, the wind often blows with great force; and the north wind, supposed to be the mountaineer's best friend, is sometimes his enemy. It not unfrequently happens that a gale renders the passage of some exposed slope or ridge too dangerous, or the intense cold produces frost-bites, so that an expedition has to be abandoned when success is within reach, which naturally is very annoying. Professor Bonney, speaking of such a gale which he experienced in 1864, says,—

"The cold was something horrible; the wind seemed to blow not round, but through me, freezing my very marrow, and making my teeth chatter like castanets; and if I stopped for a moment, I shook as if in an ague-fit. It whisked up the small spiculæ of frozen snow, and dashed them against my face with such violence that it was hardly possible to look to windward. Thin sheets of ice as large as my hand were whirled along the surface of the glacier like paper.... When these gales are raging, the drifted snow is blown far to leeward of the peaks in long streamers like delicate cirrus-clouds; and on such occasions the mountain is said by the guides fumer sa pipe (to smoke his pipe). This Mont Blanc was doing to some purpose the day that we were upon him."

It is a curious fact that these gales are often confined to the crests of the mountains, so that the wind may be raging among the peaks while a few hundred feet lower down there is comparative calm.

The chief of the prevailing winds in the Alps is the Föhn. This is a hot blast from the south which probably comes from the African deserts. On its approach the air becomes close and stifling, the sky, at first of unusual clearness, gradually thickens to a muddy and murky hue, animals become restless and disquieted by the unnatural dryness of the hot blast which now comes sweeping over the hills. In some villages, it is said, all the fires are extinguished when this wind begins to blow, for fear lest some chance spark should fall on the dry wooden roofs and set the whole place in a blaze. Still the Föhn is not altogether an "ill wind that blows nobody any good," for under its warm touch the winter snows melt away with marvellous rapidity. In the valley of Grindelwald it causes a snow-bed two feet thick to disappear in about a couple of hours, and produces in twenty-four hours a greater effect than the sun does in fifteen days. There is a Swiss proverb which rather profanely says: "If the Föhn does not blow, the golden sun and the good God can do nothing with the snow."

In summer-time, however, the south wind is never welcome, for the vapour which it brings from the Italian plains is condensed by the snows of the Alps, and streams down in torrents of rain.

A thunder-storm is always a grand spectacle. Among mountains such storms are more frequent than on the plains, and also, as might be expected, far more magnificent, especially at night. Flashes, or rather sheets, of unutterable brilliancy light up the sky; distant chains of mountains are revealed for a moment, only to be instantly eclipsed by the pall of night. Says Professor Bonney,—

"No words can adequately express the awful grandeur of these tempests when they burst among the mountains. I have often been out in them,—in fact, far more frequently than was pleasant; but perhaps the grandest of all was one that welcomed me for the first time to Chamouni. As we entered the valley, and caught sight of the white pinnacles of the glacier des Bossons, a dark cloud came rolling up rapidly from the west. Beneath it, just where two tall peaks towered up, the sky glowed like a sheet of red-hot copper, and a lurid mist spread over the neighbouring hills, wrapping them, as it seemed, in a robe of flame. Onward rolled the cloud; the lightning began to play; down the valley rushed a squall of wind, driving the dust high in air before it, and followed by a torrent of rain. Flash succeeded flash almost incessantly,—now darting from cloud to cloud; now dividing itself into a number of separate streaks of fire, and dancing all over the sky; now streaming down upon the crags, and at times even leaping up from some lofty peak into the air. The colours were often most beautiful, and bright beyond description."

The mountain traveller, when caught in a thunder-storm, undergoes a strange experience, not unattended with danger. One observer[12] thus describes his sensations:—

"A loud peal of thunder was heard; and shortly after I observed that a strange singing sound, like that of a kettle, was issuing from my alpenstock. We halted, and finding that all the axes and stocks emitted the same sound, stuck them into the snow. The guide from the hotel now pulled off his cap, shouting that his head burned; and his hair was seen to have a similar appearance to that which it would have presented had he been on an insulated stool under a powerful electrical machine. We all of us experienced the sensation of pricking and burning in some part of the body, more especially in the head and face, my hair also standing on end in an uncomfortable but very amusing manner. The snow gave out a hissing sound, as though a heavy shower of hail were falling; the veil on the wide-awake of one of the party stood upright in the air; and on waving our hands, the singing sound issued loudly from the fingers. Whenever a peal of thunder was heard, the phenomenon ceased, to be resumed before its echoes died away. At these times we felt shocks, more or less violent, in those portions of the body which were most affected. By one of these shocks my right arm was paralysed so completely that I could neither use nor raise it for several minutes, nor indeed until it had been severely rubbed; and I suffered much pain in it at the shoulder-joint for some hours."

The successive layers of snow which fall on the mountains do not remain there for ever. Unless got rid of in some way their thickness would mount up to an enormous extent. It is reckoned that on the Alps the average yearly fall of snow is thirty-three feet. In the course of a century, therefore, the height of these mountains would be increased by 3,300 feet, which we know is not the case. Various causes prevent its accumulating, among which we may mention the powerful influence of the sun's rays, the evaporation promoted by the atmosphere, the thawing influence of rain and mist, avalanches, and lastly, which is perhaps the most important, the fact that the snow composing the snowfields, as they are called, of the high regions slowly creeps down towards the valleys, where they move along as glaciers, the ends of which are gradually melted away by the warm air surrounding them, and thus the muddy glacier-streams are originated. Few perils are more dreaded by the inhabitant of the Alps than those of the avalanches. The particular way in which each avalanche descends is varied according to the shape of the mountain, the condition of the snow, and the time of the year. Hence there are three different kinds of avalanche. First, there is the ice-avalanche. The smaller glaciers, which, in the Alps, cling to the upper slopes of the higher mountains, frequently terminate abruptly on the edge of some precipice. Thus the ice, urged on by the pressure of the masses above it, moves forward until it plunges over and falls into the abyss below. Large portions break off; and these, as they bound down the cliffs, are dashed into countless pieces, which leap from crag to crag high into the air: now the falling mass, like some swollen torrent, dashes with sullen roar through a gully, now, emerging, crashes over a precipice, or spreads itself out like a fan, as it hisses down a snow-slope. These avalanches expend their force in the higher regions, and are harmless, unless any one happens to be crossing their track at the time; but accidents from this source can generally be avoided. In the distance the avalanches look like waterfalls of the purest foam, but when approached are found to be composed of fragments of ice of every size, from one, two, or more cubic yards down to tiny little balls. In spring and summer, when the white layers, softened by the heat, are falling away every hour from the lofty summits of the Alps, the pedestrian, taking up a position on some adjacent headland, may watch these sudden cataracts dashing down into the gorges from the heights of the shining peaks. Year after year travellers seated at their ease on the grassy banks of the Wengern Alp have watched with pleasure the avalanches rolling to the base of the silvery pyramid of the Jungfrau. First, the mass of ice is seen to plunge forth like a cataract, and lose itself in the lower parts of the mountain; whirlwinds of powdered snow, like clouds of bright smoke, rise far and wide into the air; and then, when the cloud has passed away, and the region has again assumed its solemn calm, the thunder of the avalanche is suddenly heard reverberating in deep echoes in the mountain gorges, as if it were the voice of the mountain itself.

The other two kinds of avalanche are composed of snow. The dust-avalanche usually falls in winter-time, when the mountains are covered deep with fresh-fallen snow. Such masses of snow, not yet compacted into ice, rest insecurely upon the icy slopes, and hang in festoons and curtains over the peaks, or lie on smooth banks of pasture, until some accident, such as a gust of wind, breaks the spell, and the whole mass slides down into the valley below. These avalanches are accompanied by fearful blasts of wind which work dire destruction. Almost the whole village of Leukerbad was destroyed by one of these on the 14th of January, 1719, and fifty-five persons perished. In 1749, more than one hundred persons were killed in the village of Ruaras (Grisons), which during the night was overwhelmed by an avalanche. So silently were some of the houses buried that the inhabitants, on waking in the morning, could not conceive why the day did not dawn. It is said, though it seems almost incredible, that in the time of the Suabian War, in the year 1498, one of these avalanches swept four hundred soldiers over a cliff, and they all escaped without serious injury.

The army of General Macdonald, in his celebrated passage of the Splügen in December, 1800, suffered severely from these dust-avalanches. A troupe of horse was completely cut through while on the march; and thirty dragoons were precipitated into a gulf below the road, where they all perished. And again, some days afterwards, in descending a gorge, the columns were repeatedly severed by avalanches; and more than one hundred soldiers, with a number of horses and mules, were lost. On one of these occasions the drummer of a regiment was carried away; and it is said that they heard him beating his drum in the gorge below, in the hope that his comrades would come to his rescue. Help, however, was out of the question. The sounds gradually became fainter, and the poor lad must have perished in the cold.

The ground-avalanches are different from those just described, consisting of dense and almost solid masses of snow which have lain for a long time exposed to atmospheric influences. They are much heavier than the dust-avalanches, and therefore more destructive; so that the inhabitants take great pains to protect themselves from this source of danger. Thickly planted trees are the best protection against avalanches of every kind. Snow which has fallen in a wood cannot very well shift its place; and when masses of snow descend from the slopes above, they are unable to break through so strong a barrier. Small shrubs, such as rhododendrons, or even heaths and meadow-grass, are often sufficient to prevent the slipping of the snow; and therefore it is very imprudent not to allow them to grow freely on mountain-slopes. But it is still more dangerous to cut down protecting forests, or even to do so partly. This was illustrated by the case of a mountain in the Pyrenees, in the lofty valley of Neste; after it had been partially cleared of trees, a tremendous avalanche fell down in 1846, and in its fall swept away more than fifteen thousand fir-trees.

The Swiss records tell us what a terrible scourge the avalanche can be in villages which in summer-time appear such calm and happy scenes of pastoral life. M. Joanne, in the introduction to his valuable "Itinéraire de la Suisse"[13] gives a list of twelve of the most destructive avalanches that have fallen in Switzerland. In old days they seem to have been as great a source of danger as in modern times. Thus we find that in the year 1500, a caravan of six hundred persons was swept away in crossing the Great St. Bernard; three hundred were buried under an avalanche which fell from Monte Cassedra (Ticino). Another one in the year 1720, at Obergestelen, in the Rhone Valley, destroyed one hundred and twenty cottages, four hundred head of cattle, and eighty-eight persons. The bodies were buried in a large pit in the village cemetery, on the wall of which was engraved the following pathetic inscription: "O God, what sorrow!—eighty-eight in a single grave!" ("Gott, welche Trauer!—acht und achtzig in einem Grab!")

It is a curious fact that animals have a wonderful power of anticipating coming catastrophes. When human beings are unaware of danger, they are often warned by the behaviour of animals. Country people sometimes say that they can tell from the birds when the weather is about to change; and there is little doubt but that sea-gulls come inland before rough, stormy weather. But in the case of earthquakes the behaviour of birds, beasts, and even fishes is very striking. It is said that before an earthquake rats, mice, moles, lizards, and serpents frequently come out of their holes, and hasten hither and thither as if smitten with terror. At Naples, it is said that the ants quitted their underground passages some hours before the earthquake of July 26, 1805; that grasshoppers crossed the town in order to reach the coast; and that the fish approached the shore in shoals. Avalanches, it is well known, produce tremors similar to those due to slight earthquake shocks; and there are many stories in Switzerland of the behaviour of animals just before the catastrophe takes place. Berlepsch relates that a pack-horse on the Scaletta Pass, which was always most steady, became restive when an avalanche was coming; so that he was valuable to his owners in bad weather. One day, when near the summit of the pass, he suddenly stopped. They foolishly took no notice of his warning this time; but he presently darted off at full speed. In a few seconds the avalanche came and buried the whole party.

If these stories can be relied upon, it would seem that animals are either more sensitive to very slight tremors of the earth, or else that they are more on the lookout than human beings. Perhaps North American Indians have learned from animals in this respect, for they can tell of a coming enemy on the march by putting their ears to the ground and listening.

But there are worse dangers in the mountains than falls of snow and ice, for sometimes masses of rock come hurtling down, or worse still, the whole side of a mountain gives way and spreads ruin far and wide. Perpendicular or overhanging rocks, which seem securely fastened, suddenly become detached and rush headlong down the mountain-side. In their rapid fall, they raise a cloud of dust like the ashes vomited forth by a volcano; a horrible darkness is spread over a once pleasant valley; and the unfortunate inhabitants, unable to see what is taking place, are only aware of the trembling of the ground, and the crashing din of the rocks as they strike together and shatter one another in pieces. When the cloud of dust is cleared away, nothing but heaps of stones and rubbish are to be seen where pastures once grew, or the peasant ploughed his acres in peace. The stream flowing down the valley is obstructed in its course, and changed into a muddy lake; the rampart of rocks from which some débris still comes crumbling down has lost its old form; the sharpened edges point out the denuded cliff from which a large part of the mountain has broken away. In the Pyrenees, Alps, and other important ranges there are but few valleys where one cannot see the confused heaps of fallen rocks.

Many of these catastrophes, known as the "Bergfall," have been recorded; and the records tell of the fearful havoc and destruction to life and property due to this cause. In Italy the ancient Roman town of Velleja was buried, about the fourth century, by the downfall of the mountain of Rovinazzo; and the large quantity of bones and coins that have been found proves that the fall was so sudden that the inhabitants had no time to escape.

Taurentum, another Roman town, situated, it is said, on the banks of Lake Geneva, at the base of one of the spurs of the Dent d'Oche, was completely crushed in A. D. 563 by a downfall of rocks. The sloping heap of débris thus formed may still be seen advancing like a headland into the waters of the lake. A terrible flood-wave, produced by the deluge of stones, reached the opposite shores of the lake and swept away all the inhabitants. Every town and village on the banks, from Morges to Vevay, was demolished, and they did not begin the work of rebuilding till the following century. Some say, however, that the disaster was caused by a landslip which fell from the Grammont or Derochiaz across the valley of the Rhone, just above the spot where it flows into the Lake of Geneva. Hundreds of such falls have taken place within the Alps and neighbouring mountains within historic times.

Two out of the five peaks of the Diablerets fell down, one in 1714 and the other in 1749, covering the pastures with a thick layer of stones and earth more than three hundred feet thick, and by obstructing the course of the stream of Lizerne, formed the three lakes of Derborence. In like manner the Bernina, the Dent du Midi, the Dent de Mayen, and the Righi have overspread with ruin vast tracts of cultivated land. In Switzerland the most noted Bergfalls are those from the Diablerets and the Rossberg. The former mountain is a long flattish ridge with several small peaks, overhanging very steep walls of rock on either side. These walls are composed of alternating beds of limestone and shale. Hence it is easily perceived that we have here conditions favourable for landslips, because if anything weakens one of these beds of shale the overlying mass might be inclined to break away. The fall in the year 1714, already referred to, was a very destructive one.

"For two whole days previously loud groaning had been heard to issue from the mountain, as though some imprisoned spirit were struggling to release himself, like Typhœus from under Etna; then a vast fragment of the upper part of the mountain broke suddenly away and thundered down the precipices into the valley beneath. In a few minutes fifty-five châlets, with sixteen men and many head of cattle, were buried for ever under the ruins. One remarkable escape has indeed been recorded, perhaps the most marvellous ever known. A solitary herdsman from the village of Avent occupied one of the châlets which were buried under the fallen mass. Not a trace of it remained; his friends in the valley below returned from their unsuccessful search, and mourned him as dead. He was, however, still among the living; a huge rock had fallen in such a manner as to protect the roof of his châlet, which, as is often the case, rested against a cliff. Above this, stones and earth had accumulated, and the man was buried alive. Death would soon have released him from his imprisonment, had not a little rill of water forced its way through the débris and trickled into the châlet. Supported by this and by his store of cheese, he lived three months, labouring all the while incessantly to escape. Shortly before Christmas he succeeded, after almost incredible toil, in once more looking on the light of day, which his dazzled eyes, so long accustomed to the murky darkness below, for a while could scarcely support. He hastened down to his home in Avent, and knocked at his own door; pale and haggard, he scarcely seemed a being of this world. His relations would not believe that one so long lost could yet be alive, and the door was shut in his face. He turned to a friend's house; no better welcome awaited him. Terror seized upon the village; the priest was summoned to exorcise the supposed demon; and it was not till he came that the unfortunate man could persuade them that he was no spectre, but flesh and blood."[14]

The valley is still a wild scene of desolation, owing to the enormous masses of stones of every shape and size with which its bed is filled.

In September of the year 1806, the second fall of the mountain Rossberg took place, after a wet summer. It is underlaid by beds of clay which, when water penetrates, are apt to give way. The part which fell was about three miles long and 350 yards wide and 33 yards thick. In five minutes one of the most fertile valleys in Switzerland was changed to a stony desert. Three whole villages, six churches, 120 houses, 200 stables or châlets, 225 head of cattle, and much land were buried under the ruins of the Rossberg; 484 persons lost their lives. Some remarkable escapes are recorded.

In the year 1618 the downfall of Monte Conto buried 2,400 inhabitants of the village of Pleurs, near Chiavenna. Excavation among the ruins was subsequently attempted, but a few mangled corpses and a church-bell were all that could be reached.

Geologically these phenomena, appalling as they are from the human point of view, possess a certain interest, and their effects deserve to be studied.

There is yet another danger to which dwellers in mountains are occasionally exposed; namely, the earthquake. It seems to be an established fact that earthquake shocks are more frequent in mountainous than in flat countries. The origin of these dangerous disturbances of the earth's crust has not yet been fully explained. They are probably caused in various ways; and it is very likely that the upheaval of mountain-chains is one of the causes at work. Earthquakes have for many years been carefully studied by scientific men, and some valuable discoveries have been made. Thus we find that they are more frequent in winter than summer, and also happen more often by night than by day. Day and night are like summer and winter on a small scale, and so we need not be surprised at this discovery. Some have maintained that there is a connection between earthquakes and the position of the moon; while others consider that the state of the atmosphere also exerts an influence, and that earthquakes are connected with rainy seasons, storms, etc. Earthquakes are very often due to volcanic eruptions, but this is not always the case (see chapter vi., page 199).

CHAPTER IV.
MOUNTAIN PLANTS AND ANIMALS.

The high hills are a refuge for the wild goats, and so are the stony rocks for the conies.—Psalm civ. 18.

There must be few people who have neither seen nor heard of the beauty and exquisite colours of Alpine[15] flowers. They are first seen on the fringes of the stately woods above the cultivated land; then in multitudes on the sloping pastures with which many mountain-chains are robed, brightening the verdure with innumerable colours; and higher up, where neither grass nor loose herbage can exist, among the slopes of shattered fragments which roll down from the mountain-tops,—nay, even amidst the glaciers,—they gladden the eye of the traveller and seem to plead sweetly with the spirits of destruction. Alpine plants fringe the vast hills of snow and ice of the high hills, and sometimes have scarcely time to flower and ripen a few seeds before being again covered by their snowy bed. When the season is unfavourable, numbers of them remain under the snow for more than a year; and here they safely rest, unharmed by the alternations of frost and biting winds, with moist and springlike days. They possess the great charm of endless variety of form and colour, and represent widely separated divisions of the vegetable kingdom; but they are all small and low-growing compared to their relatives grown in the plains, where the soil is richer and the climate milder. Among them are tiny orchids quite as interesting in their way as those from the tropics; liliputian trees, and a tree-like moss (Lycopodium dendroideum) branching into an erect little pyramid as if in imitation of a mountain pine; ferns that peep cautiously from narrow rocky crevices as if clinging to the rock for shelter from the cold blasts; bulbous plants, from lilies to bluebells; evergreen shrubs, perfect in leaf and blossom and fruit, yet so small that one's hat will cover them; exquisite creeping plants spreading freely along the ground, and when they creep over the brows of rocks or stones, draping them with curtains of colour as lovely as those we see in the forests; numberless minute plants scarcely larger than mosses, mantling the earth with fresh green carpets in the midst of winter; succulent plants in endless variety; and lastly the ferns, mosses, and lichens which are such an endless source of pleasure and delight to the traveller. In short, Alpine vegetation presents us with nearly every type of plant life of northern and temperate climes, chastened in tone and diminished in size.

It is not difficult to account for the small size of these plants; for in the first place we cannot expect a large or luxuriant growth where the air is cold, the soil scanty, and the light of the sun often obscured by clouds, and where the changes of temperature are rapid,—which is very unfavourable to most plants. Again, in the close struggle for existence which takes place on the plains and low tree-clad hills, the smaller forms of plant life are often overrun by trees, trailing plants, bushes, and vigorous herbs; but where these cannot find a home, owing to the severity of the winter and other causes, the little Alpine plants, covered up by snow in the winter, can thrive abundantly. And lastly, like the older and conquered races of men who have been driven to the hills (see chap. i., p. 28) and find shelter there, so there are both plants and animals living in the mountains which man will not suffer to live in the plain where he grows his crops, pastures his cattle, or builds his cities. We would also venture to suggest that possibly some plants have been ousted from plains by newer and more aggressive types, which came and took their place. If so, vegetable life would afford an illustration of a process which has so often taken place in human history. This is only a speculation, but still it might be worth following up. If Alpine plants, or any considerable number of them, could be shown to belong to more ancient types, such as flourished in the later geological periods, that would afford some evidence in favour of the idea. Whether this is so or not, plant life on the mountains is almost entirely protected from the destroying hands of men with their ploughs and scythes, as well as from many grazing animals. As Mr. Ruskin quaintly says:

"The flowers which on the arable plain fell before the plough now find out for themselves unapproachable places, where year by year they gather into happier fellowship and fear no evil."

It is clear that the climate of a mountainous region determines the character of the vegetation. Now, the climate will be different in different parts of a mountain-range, and will depend upon the height above the sea and other causes.[16] Some writers upon this subject have attached too much importance to absolute height above the sea, as though this were the only cause at work. It is a very important cause, no doubt, but there are others which also have a great influence, such as the position of each locality with respect to the great mountain masses, the local conditions of exposure to the sun and protection from cold winds, or the reverse. However, in spite of local irregularities there are in the Alps certain broad zones or belts of vegetation which may be briefly described as follows:—

1. The Olive region.—This region curiously illustrates what has just been said about other causes besides height influencing the climate and vegetation. For along the southern base of the Alps, the lower slopes and the mouths of the valleys have a decidedly warmer climate than the plains of Piedmont and Lombardy. Thus, while the winter climate of Milan is colder than that of Edinburgh, the olive can ripen its fruit along the skirts of the mountain region, and penetrates to a certain distance towards the interior of the chain along the lakes and the wider valleys of the Southern Alps. Even up the shores of the Lake of Garda, where the evergreen oak grows, the olive has become wild. The milder climate of the Borromean Islands, and some points on the shores of the Lago Maggiore, will permit many plants of the warmer temperate zone to grow; while at a distance of a few miles, and close to the shores of the same lake, but in positions exposed to the cold winds from the Alps, plants of the Alpine region grow freely, and no delicate perennials can survive the winter. The olive has been known to resist a temperature of about 16° F. (or 16° below the freezing point of water), but is generally destroyed by a less degree of cold. It can only be successfully cultivated where the winter frosts are neither long nor severe, where the mean temperature of winter does not fall below 42° F., and a heat of 75° F. during the day is continued through four or five months of the summer and autumn.

2. The Vine region.—The vine, being more tolerant of cold than the olive, can grow at a higher level; and so the next zone of vegetation in the Alps may be called "the Vine region." But to give tolerable wine it requires at the season of ripening of the grape almost as much warmth as the olive needs. Vines can grow in the deeper valleys throughout a great part of the Alpine chain, and in favourable situations up to a considerable height on their northern slopes. On the south side, although the limit of perpetual snow is lower, the vine often reaches near to the foot of the greater peaks. But the fitness of a particular spot for the production of wine depends far more on the direction of the valley and of the prevailing winds than on the height. And so it happens that in the Canton Valais, the Valley of the Arc in Savoy, and some others on the north side of the dividing range, tolerable wine is made at a higher level than in the valleys of Lombardy, whose direction allows the free passage of the keen northern blasts. It is a curious fact that in the Alps the vine often resists a winter temperature which would kill it down to the roots in the low country; and we must explain it by the protection of the deep winter snow. Along with the vine many species of wild plants, especially annuals, characteristic of the flora of the south of Europe, show themselves in the valleys of the Alps.

3. The Mountain region, or region of deciduous trees.—Many writers take the growth of corn as the characteristic of the colder temperate zone, corresponding to what has been called the mountain region of the Alps. But so many varieties, all with different requirements, are in cultivation, that it is impossible to take the growth of cereals in general as marking clearly any natural division of the surface. A more natural limit is marked by the presence of deciduous trees (trees which shed their leaves). Although the oak, beech, and ash do not exactly reach the same height, and are not often seen growing side by side in the Alps, yet their upper limit marks pretty accurately the transition from a temperate to a colder climate that is shown by a general change in the wild, herbaceous vegetation. The lower limit of this zone is too irregular to be exactly defined, but its upper boundary is about 4,000 feet on the cold north side of the Alps, and often rises to 5,500 feet on the southern slopes, which of course get more sunshine and warmth. The climate of this region is favourable to the growth of such trees as the oak, beech, and ash, but it does not follow that we should see them there in any great numbers at the present time; for it is probable that at a very early date they were extensively destroyed for building purposes, and to clear space for meadow and pasture land, so that with the exception of the beech forests of the Austrian Alps, there is scarcely a considerable wood of deciduous trees to be seen anywhere in the chain. In many districts where the population is not too dense, the pine and Scotch fir have taken the place of the oak and beech, mainly because the young plants are not so eagerly attacked by goats, the great destroyers of trees.

4. The region of Coniferous trees.—Botanically this region is best distinguished by the prevalence of coniferous trees, forming vast forests, which if not kept down by man (and by goats) would cover the slopes of the Alps. The prevailing species are the common fir and the silver fir. In districts where granite abounds, the larch flourishes and reaches a greater size than any other tree. Less common are the Scotch fir and the arolla, or Siberian fir. In the Eastern Alps the dwarf pine becomes conspicuous, forming a distinct zone on the higher mountains above the level of other firs. The pine forests play a most important part in the natural economy of the Alps; and their preservation is a matter of very great importance to the future inhabitants. But in some places they have been considerably diminished by cutting. This has especially happened in the neighbourhood of mines; and in consequence the people of the unfrequented communes have become so alive to this that some jealousy is felt of strangers wandering among the mountains, lest they should discover metals and cause the destruction of the woods. Their fears are not unreasonable; for the forests, besides exerting a good deal of influence on rainfall and climate, form natural defences against the rush of the spring avalanches (see chapter iii., page 93). It is recorded that after the war of 1799, in which many of those near the St. Gothard Pass were destroyed, the neighbouring villages suffered terribly from this scourge. Hence the laws do not allow of timber being cut in certain forests called "Bannwalde;" and in most places the right of felling trees is strictly regulated, and the woods are under the inspection of officials.

In spots high up among the mountains, to which access is difficult, the timber is converted into charcoal, which is then brought down in sacks by horses and mules. There are two ways in which timber is conveyed down from the forest: either it is cut up into logs some five feet long, and thrown into a neighbouring torrent, which brings it down over cliff and gorge to the valley below; or else trough-like slides are constructed along the mountain-sides, down which the trunks themselves are launched.

It is this region of coniferous trees which mainly determines the manner of life of the population of the Alps. In the month of May the horned cattle, having been fed in houses during the winter (as they are in the Scotch Highlands, where the cowsheds are called "byres"), are led up to the lower pastures. The lower châlets, occupied in May and part of June, generally stand at about the upper limit of the mountain region. Towards the middle or end of June the cattle are moved up to the chief pastures, towards the upper part of the region of coniferous trees, where they usually remain for the next two or three months. But there are some available pastures still higher up, and hither some of the cattle are sent for a month or more.

5. The Alpine region.—This is the zone of vegetation extending from the upper limit of trees to where permanent masses of snow first make their appearance; so that where the trees cease, the peculiar Alpine plants begin; but we still find shrubs, such as the common rhododendron, Alpine willow, and the common juniper, which extend up to, and the latter even beyond, the level of perpetual snow. The limits of this interesting and delightful botanical region may be fixed between 6,000 and 8,000 feet above the sea, and at least 1,000 feet higher on the south slopes of the Alps, which get more sunshine. It is used to some extent for pasture; and in Piedmont it is not uncommon to find châlets at the height of 8,500 feet, and vegetation often extends freely up to 9,500 feet. Here and there, at levels below this zone, many Alpine species may be found, either transported by accident from their natural home, or finding a permanent refuge in some cool spot sheltered from the sun, and moistened by streamlets descending from the snow region. But it is chiefly here that those delightful flowers grow which make the Alps like a great flower-garden,—great anemones, white and sulphur-coloured; gentians of the deepest blue, like the sky overhead; campanulas, geums, Alpine solanellas, and forget-me-nots; asters, ox-eyed daisies, pale pink primulas, purple heartsease, edelweiss, saxifrages, yellow poppies, Alpine toad-flax, monkshood, potentilla, and others too numerous to mention. Says Professor Bonney,—

"Who cannot recall many a happy hour spent in rambling from cluster to cluster on the side of some great Alp?—the scent of sweet herbage or of sweeter daphne perfuming the invigorating air, the melody of the cattle-bells borne up from some far-off pasture, while the great blue vault of heaven above seems reflected in the gentian clusters at his feet. The love of flowers seems natural to almost every human being, however forlorn his life may have been, however far it may have missed its appointed mark. It may well be so; they at least are fresh and untainted from their Maker's hand; the cry of 'Nature red in tooth and claw' scarce breaks their calm repose. Side by side they flourish without strife; none 'letteth or hindereth another,' yet so tender and delicate, doomed to fade all too soon, a touch of sadness is ever present to give a deeper pathos to our love."

6. The Glacial region.—This comprehends all that portion of the Alps that rises above the limit of perpetual snow. But a word of explanation is necessary. The highest parts of the Alps are not covered by one continuous sheet of snow; otherwise we should never see any peaks or crags there. Some are too steep for the snow to rest upon them, and therefore remain bare at heights much greater than the so-called "limit of perpetual snow," and that limit varies considerably. Still this term has a definite meaning when rightly understood. Leaving out of account masses of snow that accumulate in hollows shaded from the sun, the "snow-line" is fairly even, so that on viewing an Alpine range from a distance, the larger patches and fields of snow on adjoining mountains, with the same aspect, are seen to maintain a pretty constant level.