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.