FOOTNOTES:
[A] Mr. Sorby has drawn my attention to an able and interesting paper by M. Bauer, in Karsten's 'Archiv' for 1846; in which it is announced that cleavage is a tension of the mass produced by pressure. The author refers to the experiments of Mr. Hopkins as bearing upon the question.
[B] See [Appendix].
THE OBERLAND. 1856.
EXPEDITION OF 1856.
THE OBERLAND.
(2.)
On the 16th of August, 1856, I received my Alpenstock from the hands of Dr. Hooker, in the garden of the Pension Ober, at Interlaken. It bore my name, not marked, however, by the vulgar brands of the country, but by the solar beams which had been converged upon it by the pocket lens of my friend. I was the companion of Mr. Huxley, and our first aim was to cross the Wengern Alp. Light and shadow enriched the crags and green slopes as we advanced up the valley of Lauterbrunnen, and each occupied himself with that which most interested him. My companion examined the drift, I the cleavage, while both of us looked with interest at the contortions of the strata to our left, and at the shadowy, unsubstantial aspect of the pines, gleaming through the sunhaze to our right.
FOLDED ROCKS. 1856.
What was the physical condition of the rock when it was thus bent and folded like a pliant mass? Was it necessarily softer than it is at present? I do not think so. The shock which would crush a railway carriage, if communicated to it at once, is harmless when distributed over the interval necessary for the pushing in of the buffer. By suddenly stopping a cock from which water flows you may burst the conveyance pipe, while a slow turning of the cock keeps all safe. Might not a solid rock by ages of pressure be folded as above? It is a physical axiom that no body is perfectly hard, none perfectly soft, none perfectly elastic. The hardest body subjected to pressure yields, however little, and the same body when the pressure is removed cannot return to its original form. If it did not yield in the slightest degree it would be perfectly hard; if it could completely return to its original shape it would be perfectly elastic.
Let a pound weight be placed upon a cube of granite; the cube is flattened, though in an infinitesimal degree. Let the weight be removed, the cube remains a little flattened; it cannot quite return to its primitive condition. Let us call the cube thus flattened No. 1. Starting with No. 1 as a new mass, let the pound weight be laid upon it; the mass yields, and on removing the weight it cannot return to the dimensions of No. 1; we have a more flattened mass, No. 2. Proceeding in this manner, it is manifest that by a repetition of the process we should produce a series of masses, each succeeding one more flattened than the former. This appears to be a necessary consequence of the physical axiom referred to above.
Now if, instead of removing and replacing the weight in the manner supposed, we cause it to rest continuously upon the cube, the flattening, which above was intermittent, will be continuous; no matter how hard the cube may be, there will be a gradual yielding of its mass under the pressure. Apply this to squeezed rocks—to those, for example, which form the base of an obelisk like the Matterhorn; that this base must yield, seems a certain consequence of the physical constitution of matter: the conclusion seems inevitable that the mountain is sinking by its own weight. Let two points be fixed, one near the summit, the other near the base of the obelisk; next year these points will have approached each other. Whether the amount of approach in a human lifetime be measureable we know not; but it seems certain that ages would leave their impress upon the mass, and render visible to the eye an action which at present is appreciable by the imagination only.
THE JUNGFRAU AND SILBERHORN. 1856.
We halted on the night of the 16th at the Jungfrau Hotel, and next morning we saw the beams of the rising sun fall upon the peaked snow of the Silberhorn. Slowly and solemnly the pure white cone appeared to rise higher and higher into the sunlight, being afterwards mottled with gold and gloom, as clouds drifted between it and the sun. I descended alone towards the base of the mountain, making my way through a rugged gorge, the sides of which were strewn with pine-trees, splintered, broken across, and torn up by the roots. I finally reached the end of a glacier, formed by the snow and shattered ice which fall from the shoulders of the Jungfrau. The view from this place had a savage magnificence such as I had not previously beheld, and it was not without some slight feeling of awe that I clambered up the end of the glacier. It was the first I had actually stood upon. The loneliness of the place was very impressive, the silence being only broken by fitful gusts of wind, or by the weird rattle of the débris which fell at intervals from the melting ice.
AVALANCHES. 1856.
Once I noticed what appeared to be the sudden and enormous augmentation of the waters of a cascade, but the sound soon informed me that the increase was due to an avalanche which had chosen the track of the cascade for its rush. Soon afterwards my eyes were fixed upon a white slope some thousands of feet above me; I saw the ice give way, and, after a sensible interval, the thunder of another avalanche reached me. A kind of zigzag channel had been worn on the side of the mountain, and through this the avalanche rushed, hidden at intervals, and anon shooting forth, and leaping like a cataract down the precipices. The sound was sometimes continuous, but sometimes broken into rounded explosions which seemed to assert a passionate predominance over the general level of the roar. These avalanches, when they first give way, usually consist of enormous blocks of ice, which are more and more shattered as they descend. Partly to the echoes of the first crash, but mainly, I think, to the shock of the harder masses which preserve their cohesion, the explosions which occur during the descent of the avalanche are to be ascribed. Much of the ice is crushed to powder; and thus, when an avalanche pours cataract-like over a ledge, the heavier masses, being less influenced by the atmospheric resistance, shoot forward like descending rockets, leaving the lighter powder in trains behind them. Such is the material of which a class of the smaller glaciers in the Alps is composed. They are the products of avalanches, the crushed ice being recompacted into a solid mass, which exhibits on a smaller scale most of the characteristics of the large glaciers.
After three hours' absence I reascended to the hotel, breakfasted, and afterwards returned with Mr. Huxley to the glacier. While we were engaged upon it the weather suddenly changed; lightning flashed about the summits of the Jungfrau, and thunder "leaped" among her crags. Heavy rain fell, but it cleared up afterwards with magical speed, and we returned to our hotel. Heedless of the forebodings of many prophets of evil weather we set out for Grindelwald. The scene from the summit of the Little Scheideck was exceedingly grand. The upper air exhibited a commotion which we did not experience; clouds were wildly driven against the flanks of the Eiger, the Jungfrau thundered behind, while in front of us a magnificent rainbow, fixing one of its arms in the valley of Grindelwald, and, throwing the other right over the crown of the Wetterhorn, clasped the mountain in its embrace. Through jagged apertures in the clouds floods of golden light were poured down the sides of the mountain. On the slopes were innumerable chalets, glistening in the sunbeams, herds browsing peacefully and shaking their mellow bells; while the blackness of the pine-trees, crowded into woods, or scattered in pleasant clusters over alp and valley, contrasted forcibly with the lively green of the fields.
THE HEISSE PLATTE. 1856.
At Grindelwald, on the 18th, we engaged a strong and competent guide, named Christian Kaufmann, and proceeded to the Lower Glacier. After a steep ascent, we gained a point from which we could look down upon the frozen mass. At first the ice presented an appearance of utter confusion, but we soon reached a position where the mechanical conditions of the glacier revealed themselves, and where we might learn, had we not known it before, that confusion is merely the unknown intermixture of laws, and becomes order and beauty when we rise to their comprehension. We reached the so-called Eismeer—Ice Sea. In front of us was the range of the Viescherhörner, and a vast snow slope, from which one branch of the glacier was fed. Near the base of this névé, and surrounded on all sides by ice, lay a brown rock, to which our attention was directed as a place noted for avalanches; on this rock snow or ice never rests, and it is hence called the Heisse Platte—the Hot Plate. At the base of the rock, and far below it, the glacier was covered with clean crushed ice, which had fallen from a crown of frozen cliffs encircling the brow of the rock. One obelisk in particular signalised itself from all others by its exceeding grace and beauty. Its general surface was dazzling white, but from its clefts and fissures issued a delicate blue light, which deepened in hue from the edges inwards. It stood upon a pedestal of its own substance, and seemed as accurately fixed as if rule and plummet had been employed in its erection. [Fig. 1] represents this beautiful minaret of ice.
ICE MINARET. 1856.
While we were in sight of the Heisse Platte, a dozen avalanches rushed downwards from its summit. In most cases we were informed of the descent of an avalanche by the sound, but sometimes the white mass was seen gliding down the rock, and scattering its smoke in the air, long before the sound reached us. It is difficult to reconcile the insignificant appearance presented by avalanches, when seen from a distance, with the volume of sound which they generate; but on this day we saw sufficient to account for the noise. One block of solid ice which we found below the Heisse Platte measured 7 feet 6 inches in length, 5 feet 8 inches in height, and 4 feet 6 inches in depth. A second mass was 10 feet long, 8 feet high, and 6 feet wide. It contained therefore 480 cubic feet of ice, which had been cast to a distance of nearly 1000 yards down the glacier. The shock of such hard and ponderous projectiles against rocks and ice, reinforced by the echoes from the surrounding mountains, will appear sufficient to account for the peals by which their descent is accompanied.
ECHOES OF THE WETTERHORN. 1856.
A second day, in company with Dr. Hooker, completed the examination of this glacier in 1856; after which I parted from my friends, Mr. Huxley intending to rejoin me at the Grimsel. On the morning of the 20th of August I strapped on my knapsack and ascended the green slopes from Grindelwald towards the Great Scheideck. Before reaching the summit I frequently heard the wonderful echoes of the Wetterhorn. Some travellers were in advance of me, and to amuse them an alpine horn was blown. The direct sound was cut off from me by a hill, but the echoes talked down to me from the mountain walls. The sonorous waves arrived after one, two, three, and more reflections, diminishing gradually in intensity, but increasing in softness, as if in its wanderings from crag to crag the sound had undergone a kind of sifting process, leaving all its grossness behind, and returning in delightful flute notes to the ear.
Let us investigate this point a little. If two looking-glasses be placed perfectly parallel to each other, with a lighted candle between them, an infinite series of images of the candle will be seen at both sides, the images diminishing in brightness the further they recede. But if the looking-glasses, instead of being parallel, enclose an angle, a limited number of images only will be seen. The smaller the angle which the reflectors make with each other, or, in other words, the nearer they approach parallelism, the greater will be the number of images observed.
To find the number of images the following is the rule:—Divide 360, or the number of degrees in a circle, by the number of degrees in the angle enclosed by the two mirrors, the quotient will be one more than the number of images; or, counting the object itself, the quotient is always equal to the number of images plus the object. In [Fig. 2] I have given the number and position of the images produced by two mirrors placed at an angle of 45°. a b and b c mark the edges of the mirrors, and 0 represents the candle, which, for the sake of simplicity, I have placed midway between them. Fix one point of a pair of compasses at B, and with the distance B 0 sweep a circle:—all the images will be ranged upon the circumference of this circle. The number of images found by the foregoing rule is 7, and their positions are marked in the figure by the numbers 1, 2, 3, &c.
ECHOES EXPLAINED. 1856.
Suppose the ear to occupy the place of the eye, and that a sounding body occupies the place of the luminous one, we should then have just as many echoes as we had images in the former case. These echoes would diminish in loudness just as the images of the candle diminish in brightness. At each reflection a portion both of sound and light is lost; hence the oftener light is reflected the dimmer it becomes, and the oftener sound is reflected the fainter it is.
Now the cliffs of the Wetterhorn are so many rough angular reflectors of the sound: some of them send it back directly to the listener, and we have a first echo; some of them send it on to others from which it is again reflected, forming a second echo. Thus, by repeated reflection, successive echoes are sent to the ear, until, at length, they become so faint as to be inaudible. The sound, as it diminishes in intensity, appears to come from greater and greater distances, as if it were receding into the mountain solitudes; the final echoes being inexpressibly soft and pure.
REICHENBACH AND HANDECK. 1856.
After crossing the Scheideck I descended to Meyringen, visiting the Reichenbach waterfall on my way. A peculiarity of the descending water here is, that it is broken up in one of the basins into nodular masses, each of which in falling leaves the light foaming mass which surrounds it as a train in the air behind; the effect exactly resembles that of the avalanches of the Jungfrau, in which the more solid blocks of ice shoot forward in advance of the lighter débris, which is held back by the friction of the air.
Next day I ascended the valley of Hasli, and observed upon the rocks and mountains the action of ancient glaciers which once filled the valley to the height of more than a thousand feet above its present level. I paused, of course, at the waterfall of Handeck, and stood for a time upon the wooden bridge which spans the river at its top. The Aar comes gambolling down to the bridge from its parent glacier, takes one short jump upon a projecting ledge, boils up into foam, and then leaps into a chasm, from the bottom of which its roar ascends through the gloom. A rivulet named the Aarlenbach joins the Aar from the left in the very jaws of the chasm: falling, at first, upon a projection at some depth below the edge, and, rebounding from this, it darts at the Aar, and both plunge together like a pair of fighting demons to the bottom of the gorge. The foam of the Aarlenbach is white, that of the Aar is yellow, and this enables the observer to trace the passage of the one cataract through the other. As I stood upon the bridge the sun shone brightly upon the spray and foam; my shadow was oblique to the river, and hence a symmetrical rainbow could not be formed in the spray, but one half of a lovely bow, with its base in the chasm, leaned over against the opposite rocks, the colours advancing and retreating as the spray shifted its position. I had been watching the water intently for some time, when a little Swiss boy, who stood beside me, observed, in his trenchant German, "There plunge stones ever downwards." The stones were palpable enough, carried down by the cataract, and sometimes completely breaking loose from it, but I did not see them until my attention was withdrawn from the water.
HUT OF M. DOLLFUSS. 1856.
On my arrival at the Grimsel I found Mr. Huxley already there, and, after a few minutes' conversation, we decided to spend a night in a hut built by M. Dollfuss in 1846, beside the Unteraar glacier, about 2000 feet above the Hospice. We hoped thus to be able to examine the glacier to its origin on the following day. Two days' food and some blankets were sent up from the Hospice, and, accompanied by our guide, we proceeded to the glacier.
HÔTEL DES NEUFCHÂTELOIS. 1856.
Having climbed a great terminal moraine, and tramped for a considerable time amid loose shingle and boulders, we came upon the ice. The finest specimens of "tables" which I have ever seen are to be found upon this glacier—huge masses of clean granite poised on pedestals of ice. Here are also "dirt-cones" of the largest size, and numerous shafts, the forsaken passages of ancient "moulins," some filled with water, others simply with deep blue light. I reserve the description and explanation of both cones and moulins for another place. The surfaces of some of the small pools were sprinkled lightly over with snow, which the water underneath was unable to melt; a coating of snow granules was thus formed, flexible as chain armour, but so close that the air could not escape through it. Some bubbles which had risen through the water had lifted the coating here and there into little rounded domes, which, by gentle pressure, could be shifted hither and thither, and several of them collected into one. We reached the hut, the floor of which appeared to be of the original mountain slab; there was a space for cooking walled off from the sleeping-room, half of which was raised above the floor, and contained a quantity of old hay. The number 2404 mètres, the height, I suppose, of the place above the sea, was painted on the door, behind which were also the names of several well-known observers—Agassiz, Forbes, Desor, Dollfuss, Ramsay, and others—cut in the wood. A loft contained a number of instruments for boring, a surveyor's chain, ropes, and other matters. After dinner I made my way alone towards the junction of the Finsteraar and Lauteraar glaciers, which unite at the Abschwung to form the trunk stream of the Unteraar glacier. Upon the great central moraine which runs between the branches were perched enormous masses of rock, and, under the overhanging ledge of one of these, M. Agassiz had his Hôtel des Neufchâtelois. The rock is still there, bearing traces of names now nearly obliterated by the weather, while the fragments around also bear inscriptions. There in the wilderness, in the gray light of evening, these blurred and faded evidences of human activity wore an aspect of sadness. It was a temple of science now in ruins, and I a solitary pilgrim to the desecrated blocks. As the day declined, rain began to fall, and I turned my face towards my new home; where in due time we betook ourselves to our hay, and waited hopefully for the morning.
But our hopes were doomed to disappointment. A vast quantity of snow fell during the night, and, when we arose, we found the glacier covered, and the air thick with the descending flakes. We waited, hoping that it might clear up, but noon arrived and passed without improvement; our fire-wood was exhausted, the weather intensely cold, and, according to the men's opinion, hopelessly bad; they opposed the idea of ascending further, and we had therefore no alternative but to pack up and move downwards. What was snow at the higher elevations changed to rain lower down, and drenched us completely before we reached the Grimsel. But though thus partially foiled in our design, this visit taught us much regarding the structure and general phenomena of the glacier.
THE RHONE GLACIER. 1856.
The morning of the 24th was clear and calm: we rose with the sun, refreshed and strong, and crossed the Grimsel pass at an early hour. The view from the summit of the pass was lovely in the extreme; the sky a deep blue, the surrounding summits all enamelled with the newly-fallen snow, which gleamed with dazzling whiteness in the sunlight. It was Sunday, and the scene was itself a Sabbath, with no sound to disturb its perfect rest. In a lake which we passed the mountains were mirrored without distortion, for there was no motion of the air to ruffle its surface. From the summit of the Mayenwand we looked down upon the Rhone glacier, and a noble object it seemed,—I hardly know a finer of its kind in the Alps. Forcing itself through the narrow gorge which holds the ice cascade in its jaws, and where it is greatly riven and dislocated, it spreads out in the valley below in such a manner as clearly to reveal to the mind's eye the nature of the forces to which it is subjected. Longfellow's figure is quite correct; the glacier resembles a vast gauntlet, of which the gorge represents the wrist; while the lower glacier, cleft by its fissures into finger-like ridges, is typified by the hand.
Furnishing ourselves with provisions at the adjacent inn, we devoted some hours to the examination of the lower portion of the glacier. The dirt upon its surface was arranged in grooves as fine as if produced by the passage of a rake, while the laminated structure of the deeper ice always corresponded to the superficial grooving. We found several shafts, some empty, some filled with water. At one place our attention was attracted by a singular noise, evidently produced by the forcing of air and water through passages in the body of the glacier; the sound rose and fell for several minutes, like a kind of intermittent snore, reminding one of Hugi's hypothesis that the glacier was alive.
RINGS AROUND THE SUN. 1856.
We afterwards climbed to a point from which the whole glacier was visible to us from its origin to its end. Adjacent to us rose the mighty mass of the Finsteraarhorn, the monarch of the Oberland. The Galenstock was also at hand, while round about the névé of the glacier a mountain wall projected its jagged outline against the sky. At a distance was the grand cone of the Weisshorn, then, and I believe still, unscaled;[A] further to the left the magnificent peaks of the Mischabel; while between them, in savage isolation, stood the obelisk of the Matterhorn. Near us was the chain of the Furca, all covered with shining snow, while overhead the dark blue of the firmament so influenced the general scene as to inspire a sentiment of wonder approaching to awe. We descended to the glacier, and proceeded towards its source. As we advanced an unusual light fell upon the mountains, and looking upwards we saw a series of coloured rings, drawn like a vivid circular rainbow quite round the sun. Between the orb and us spread a thin veil of cloud on which the circles were painted; the western side of the veil soon melted away, and with it the colours, but the eastern half remained a quarter of an hour longer, and then in its turn disappeared. The crevasses became more frequent and dangerous as we ascended. They were usually furnished with overhanging eaves of snow, from which long icicles depended, and to tread on which might be fatal. We were near the source of the glacier, but the time necessary to reach it was nevertheless indefinite, so great was the entanglement of fissures. We followed one huge chasm for some hundreds of yards, hoping to cross it; but after half an hour's fruitless effort we found ourselves baffled and forced to retrace our steps.
SPIRIT OF THE BROCKEN. 1856.
The sun was sloping to the west, and we thought it wise to return; so down the glacier we went, mingling our footsteps with the tracks of chamois, while the frightened marmots piped incessantly from the rocks. We reached the land once more, and halted for a time to look upon the scene within view. The marvellous blueness of the sky in the earlier part of the day indicated that the air was charged, almost to saturation, with transparent aqueous vapour. As the sun sank the shadow of the Finsteraarhorn was cast through the adjacent atmosphere, which, thus deprived of the direct rays, curdled up into visible fog. The condensed vapour moved slowly along the flanks of the mountain, and poured itself cataract-like into the valley of the Rhone. Here it met the sun again, which reduced it once more to the invisible state. Thus, though there was an incessant supply from the generator behind, the fog made no progress; as in the case of the moving glacier, the end of the cloud-river remained stationary where consumption was equal to supply. Proceeding along the mountain to the Furca, we found the valley at the further side of the pass also filled with fog, which rose, like a wall, high above the region of actual shadow. Once on turning a corner an exclamation of surprise burst simultaneously from my companion and myself. Before each of us and against the wall of fog, stood a spectral image of a man, of colossal dimensions; dark as a whole, but bounded by a coloured outline. We stretched forth our arms; the spectres did the same. We raised our alpenstocks; the spectres also flourished their bâtons. All our actions were imitated by these fringed and gigantic shades. We had, in fact, the Spirit of the Brocken before us in perfection.
At the time here referred to I had had but little experience of alpine phenomena. I had been through the Oberland in 1850, but was then too ignorant to learn much from my excursion. Hence the novelty of this day's experience may have rendered it impressive: still even now I think there was an intrinsic grandeur in its phenomena which entitles the day to rank with the most remarkable that I have spent among the Alps. At the Furca, to my great regret, the joint ramblings of my friend and myself ended; I parted from him on the mountain side, and watched him descending, till the gray of evening finally hid him from my view.