I have already shown that, under the highest latitudes, men find, in the exceptional activity of their functions of nutrition, and, above all, of respiration, a powerful re-agent against the intensity of the external cold. This resource fails him on the mountain summit. In vain will he attempt, as a succedaneum against the cold, to modify his ordinary regimen, to drink warm blood, to eat fat and raw flesh; his stomach will reject such aliment, or digest it only with difficulty, and he will not suffer less from the extreme rigour of the temperature. At the Pole air pours freely into our lungs, and its pressure stoutly maintains the equilibrium of the fluids of our body. Such is not the case when we soar, Icarus like, into the higher regions of the atmosphere; in proportion as we ascend, the air rarefies, and its pressure diminishes. Consequently, respiration becomes difficult and painful; the quantity of oxygen designed to cherish animal heat by the combustion of the carbon and hydrogen of the blood becomes insufficient; at the same time, the tissues and the liquids which they enclose expand; perspiration, instead of diminishing, experiences a relative augmentation; if the atmospheric pressure is much too weak, the blood extravasates, and forces itself out through the nose, the ears, and the pores of the skin. In a word, that peculiar malady which has been named the mal des montagnes, and which is not always unattended with danger, attacks the hardiest traveller, and compels him with all speed to return to lower and securer levels.
When, therefore, we speak of “the pure and living air” of the mountains, of the vigour and health of their inhabitants—even as the poet says—
“An iron race the mountain-cliffs maintain”—
we are really to understand those lofty hills which are decorated in some places with the name of mountains, or the table-lands that form the first steps of the great chains. Such, indeed, are the only inhabited and inhabitable mountains. There only is the cultivation of a few plants still possible; there only can the wild beasts find an asylum in wood or forest, and the cattle green fields of pasture; there may man plant his feet, build his dwellings, devote himself to rearing his herds, to the chase, or to more sedentary industries. Let us remember, moreover, that the salubrity of the air of elevated districts has been greatly exaggerated, and that if we meet with many mountaineers agile, robust, and intelligent, we also meet with a great number affected by organic diseases either wholly unknown or very rare in the plains, such as goître, scrofula, and cretinism.
The structure of the mountains, their form, and the nature of their soil, suffice, even without these meteorological conditions I have just indicated, to render them impracticable as the dwelling-place of man and of most animals. To ascend them is almost always an enterprise of the most hazardous, frequently of the most perilous character. To climb the lofty peaks of the Himalaya, to scale the majestic brow of Chimborazo, to ascend the frozen sides of the Jungfrau or Mont Blanc, is an achievement of which the boldest boast, as if they had won a Waterloo or an Inkermann! Only a keen longing after that notoriety which for some minds fills the place of renown, or a passion for dangerous enterprise such as stimulates the pioneer or the explorer, or a powerful scientific and artistic interest, can impel the Alpine adventurer—can instigate a Saussure, a Forbes, a Pentland, or a Tyndall, to mount the scarped ramparts of primeval rocks, to tread warily along precipices which the chamois can scarcely traverse, to escalade the savage cliffs and frozen pinnacles, and to breathe
“The difficult air of the iced mountain-tops.”
The annals of mountaineering are illuminated with many stirring stories of human endurance, patience, and heroism; but, alas! the page is too often robed in black, and too frequently records the death of some unhappy explorer!
It is no part of my plan to trace the geological history of mountains. We know that their formation has been attributed, according to a satisfactory theory, to the upheavals and expansions of the igneous matter which, in the primitive ages, boiled under the solid crust produced by the superficial solidification of our planet, and whose ebullition, though considerably decreased, even in our own days is frequently made known in volcanic phenomena and earthquakes. At divers epochs the crust of the globe will have been rent and dislocated, giving vent to floods of fused mineral matter; these, solidifying in their turn, will have produced those inequalities of the earth’s surface which we call mountains; enormous inequalities, as they appear to us; mole-hills or grains of sand if we compare them with the volume of the terrestrial sphere.
The distribution of the mountains over the surface of the continents and islands, and the forms which they have assumed, seem, at the first glance, altogether capricious and irregular. Yet an attentive study speedily demonstrates that some higher law than that of chance presided at the violent and tumultuous production of these majestic masses. Thus, in the first place, it is evident that every mountain not a volcano connects itself of necessity to other mountains, and forms a chain of greater or less length, which departs a little from the straight line, or rather from the arc of the great circle. The principal chains throw out branches, and by mountain knots, as they are called, unite with other secondary chains—the whole composing a mountain system; but the apparent irregularities of these systems may always be referred to one common direction.
If from the disposition of mountains we pass to their distribution, we perceive that all chains which have sprung from the same geological convulsion are always distinctly parallel, and the successive chains distinctly perpendicular among themselves; so that the age of a chain is known by its direction. Nor is there anything to astonish us in this species of symmetry, when we recollect that every substance previously liquefied or diluted by heat, and which, while cooling, becomes contracted by the closer compression of its atoms, splits with a certain degree of regularity, generally following lines which intersect each other at right angles. And it is through the crevices of the cooled terrestrial crust that these fused matters have escaped, according to the hypothesis generally admitted by geologists, which, by solidifying in their turn, have created the mountains. I can only indicate these considerations to the reader; their development would beguile us too far from our prescribed path.