Tais Grimsel is a weird regiona monument carved with hieroglyphics more ancient and more grand than those of Nineveh or the Nile. It is a world disinterred by the sun from a sepulchre of ice. All around are evidences of the existence and the might of the glaciers which once held possession of the place. All around the rocks are carved, and fluted, and polished, and scored. Here and there angular pieces of quartz, held fast by the ice, inserted their edges into the rocks and scratched them like diamonds, the scratches varying in depth and width according to the magnitude of the cutting stone. Larger masses, held similarly captive, scooped longitudinal depressions in the rocks over which they passed, while in many cases the polishing must have been effected by the ice itself. A raindrop will wear a stone away ; much more would an ice surface, squeezed into perfect contact by enormous pressure, rub away the asperities of the rocks over which foiages it was forced to slide. The rocks thus polished by the ice itself are so exceedingly smooth and slippery that it is impossible to stand on them where their inclination is at all considerable. But what a world it must have been when the valleys were thus filled ! We can restore the state of things in thought, and in doing so we submerge many a mass which now lifts its pinnacle skyward. Switzerland in those days could not be so grand as it is now. Pour ice into those valleys till they are filled, and you eliminate those contrasts of height and. depth on which the grandeur of Alpine scenery depends. Instead of skiey pinnacles and deep-cut gorges we should have an icy sea dotted with dreary islands formed by the highest mountain-tops.
In the afternoon I strolled up to the Siedelhorn. As I stood upon the broken summit of the mountain the air was without a cloud ; and the sunbeams fell directly against the crown and slopes of the Galenstock at the base of which lay the glacier of the Rhone. The level sea of névé above the great ice-cascade, the fall itself,’ and the terminal glacier below the fall were all apparently at hand. At the base of the fall the ice undergoes an extraordinary transformation ; it reaches this place more or less amorphous, it quits it most beautifully laminated, the change being due to the pressure endured at the bottom of the fall. The wrinkling of the glacier here was quite visible, the dwindling of the wrinkles into bands, and the subdivision of these bands into lines which mark the edges of the laminæ of which the glacier at this place is made up. Beyond, amid the mountains at the opposite side of the Rhone valley, lay the Gries glacier, half its snow in shadow, and half illuminated by the sinking sun. Round farther to the right were the Monte Leone and other grand masses, the grandest here being the Mischabel with its crowd of snowy cones. Jumping a gap in the mountains, we hit the stupendous cone of the Weisshorn, which slopes to meet the inclines of the Mischabel, and in the wedge of space carved out between the two the Matterhorn lifts its terrible head.
Wheeling farther in the same direction, we at length strike the mighty spurs of the Finsteraarhorn, between two of which lies the Oberaar glacier. Here is no turmoil of crevasses, no fantastic ice-pinnacles, nothing to indicate the operation of those tremendous forces by which a glacier sometimes rends its own breast. The grimmest giant of the Ober-land closes the view at the head of the Lauteraar glacierthe Schreckhorn, whose cliffs on this side no mountaineer will ever scale. Between the Schreckhorn and Finsteraarhorn a curious group of peaks encircle a flat snow-field, from which the sunbeams are flung in blazing lines. Immediatcly below is the Unteraar glacier, with a long black streak upon its back, bent hither and thither, like a serpent wriggling down the valley. Beyond it and flanking it is a ridge of mountains with a crest of vertical rock, hacked into indentations which suggest a resemblance to a cock’s comb. To the very root of the comb the mountains have been planed by the ancient ice.
A scene of unspeakable desolation it must have been when not Switzerland alone, but all Europe, was thus encased in frozen armourwhen a glacier from Ben Nevis dammed the mouth of Glenroy, and Llanberis and Borrodale were ploughed by frozen shares sent down by Snowdon and Scawfellwhen from the Reeks of Magillicuddy came the navigators which dug out space for the Killarney lakes, and carved through the mountains the Gap of Dunloe.’ Evening came, and I moved downwards, over heaped boulders and tufted alp ; down with headlong speed over the rounded rocks of the Grimsel, making long -springs at intervals, over the polished inclines, and reaching the hospice as the bell rings its inmates to their evening meal.
On Saturday I ascended from Viesch to the Hotel Jungfrau on the slope of the AEggischnorn, and in the evening walked up to the summit of the mountain alone As usual, I wandered unconsciously from the beaten track, getting into a chaos of crags which had been shaken from the heights. My ascent was quick, and I soon found myself upon the crest of broken rocks which caps the mountain. The peak and those adjacent, which are similarly shattered, exhibit a striking picture of the ruin which nature inflicts upon her own creations. She buildeth up and taketh down. She lifts the mountains by her subterranean energies, and then blasts them by her lightnings and her frost. Thus grandly she rushes along the ‘ grooves of change’ to her unattainable repose. Is it unattainable ? The incessant tendency of material forces is toward final equilibrium ; and if the quantity of this tendency be finite, a time of repose must come at last. If one portion of the universe be hotter than another, a flux instantly sets in to equalise the temperatures; while winds blow and rivers roll in search of a stable equilibrium. Matter longs for rest ; when is this longing to be fully satisfied ? If satisfied, what then ? Rest is not perfection ; it is death. Life is only compatible with mutation ; when equilibrium sets in life ceases, and the world thenceforward is locked in everlasting sleep.
A wooden cross bleached by many storms surmounts the pinnacle of the .Eggischhorn, and at the base of it I now take my place and scan the surrounding scene. Down from its birthplace in the mountains comes that noblest of ice-streams the Great Aletsch glacier. Its arms are thrown round the shoulders of the Jungfrau, while from the Monk and the Trugberg, the Gletscherhorn, the Breithorn, the Aletschhorn, and many another noble pile, the tributary snows descend and thicken into ice. The mountains are well protected by their wintry coats, and hence the quantity of débris upon the glacier is comparatively small ; still, along it can be noticed dark longitudinal streaks, which are incipient moraines. Right and left from these longitudinal bands sweep finer curves, twisted here and there into complex windings, which mark the lamination of the subjacent ice. The glacier lies in a curved valley, the side towards which its convex curvature is turned is thrown into a state of strain, the ice breaks across the line of tension, a curious system of oblique glacier ravines being thus produced. From the snow-line which crosses the glacier above the Faulberg a pure snow-field stretches upward to the Col de la Jungfrau, which unites the Maiden to the Monk. Skies and summits are to-day without a cloud, and no mist or turbidity interferes with the sharpness of the outlines. Jungfrau, Monk, Eiger, Trugberg, cliffy Strahlgrat, stately, lady-like Aletschhorn, all grandly pierce the empyrean. Like a Saul of mountains, the Finsteraarhorn overtops all his neighbours ; then we have the Oberaarhorn, with the river glacier of Viesch rolling from his shoulders. Below is the Märjelin See, with its crystal precipices and its floating icebergs, snowy white, sailing on a blue-green sea. Beyond is the range which divides the Valais from Italy. Sweeping round, the vision meets an aggregate of peaks which look, as fledglings to their mother, towards the mighty Dom. Then come the repellent crags of Mont Cervin, the idea of moral savagery, of wild untameable ferocity, mingling involuntarily with our contemplation of the gloomy pile. Next comes an object scarcely less grand, conveying it may be even a deeper impression of majesty and might than the Matterhorn itselfthe Weisshorn, perhaps the most splendid object in the Alps. But beauty is associated with its force, and we think of it, not as cruel, but as grand and strong. Further to the right is the Great Combin ; other peaks crowd around him, while at the extremity of the curve along which the gaze has swept rises the sovran crown of Mont Blanc. And now, as the day sinks, scrolls of pearly clouds form around the mountain-crests, and are wafted from them into the distant air. They are without colour of any kind ; but their grace of form and lustre are not to be described.
NOTE ON CLOUDS
Ir is well known that when a receiver filled with ordinary undried air is exhausted, a cloudinesst due to the precipitation of the aqueous vapour diffused in the air, is produced by the first few strokes of the pump. It is, as might be expected, possible to produce clouds in this way with the vapours of other liquids than water.
In the course of some experiments on the chemical action of light on vapours which have been communicated to the Royal Society, I had frequent occasion to observe the precipitation of such clouds; indeed, several days at a time have been devoted solely to the generation and examination of clouds formed by the sudden dilatation of mixed air and vapours in the experimental tubes.
The clouds were generated in two ways : one mode consisted in opening the passage between the filled experimental tube and the air-pump, and then simply dilating the air by working the pump. In the other, the experimental tube was connected with a vessel of suitable size, the passage between which and the experimental tube could be closed by a stopcock. This vessel was first exhausted ; on turning the, cock the air rushed from the experimental tube into the vessel, the precipitation of a cloud within the tube being a consequence of the transfer. Instead of a special vessel, the cylinders of the air-pump itself were usually employed for this purpose.
It was found possible, by shutting off the residue of air and vapour after each act of precipitation, and again exhasting the cylinders of the pump, to obtain with some substances, and without refilling the experimental tube, fifteen or twenty clouds in succession.
The clouds thus precipitated differed from each other in luminous energy, some shedding forth a mild white light, others flashing out with sudden and surprising brilliancy. This difference of action is, of course, to be referred to the different reflective energies of the particles of the clouds, which were produced by substances of very different refractive indices.
Different clouds, moreover, possess very different degrees of stability : some melt away rapidly, while others linger for minutes in the experimental tube, resting, as they slowly dissolve, upon its bottom like a heap of snow. The particles of other clouds are trailed through the experimental tube as if they were moving through a viscous medium.
Nothing can exceed the splendour of the diffraction phenomena exhibited by some of these clouds; the colours are best seen by looking along the experimental tube from a point above it, the face being turned towards the source of illumination. The differential motions introduced by friction against the interior surface of the tube often cause the colours to arrange themselves in distinct layers.
The difference in texture exhibited by different clouds caused me to look a little more closely than I had previously done into the mechanism of cloud-formation. A certain expansion is necessary to bring down the cloud ; the moment just before precipitation the cooling air and vapour may be regarded as divided into a number of polyhedra, the particles along the bounding surfaces of which move in opposite directions when precipitation actually sets in. Every cloud-particle has consumed a polyhedron of vapour in its formation ; and it is manifest that the size of the particle must depend, not only on the size of the vapour polyhedron, but also on the relation of the density of the vapour to that of its liquid. If the vapour were light, and the liquid heavy, other things being equal, the cloud-particle would be smaller than if the vapour were heavy and the liquid light. There would evidently be more shrinkage in the one case than in the other; these considerations were found valid throughout the experiments ; the case of toluol may be taken as representative of a great number of others. The specific gravity of this liquid is 0.85, that of water being unity ; the specific gravity of its vapour is 3.26, that of aqueous vapour being 0.6. Now, as the size of the cloud-particle is directly proportional to the specific gravity of the vapour, and inversely proportional to the specific gravity of the liquid, an easy calculation proves that, assuming the size of the vapour polyhedra in both cases to be the same, the size of the particle of toluol cloud must be more than six times that of the particle of aqueous cloud. It is probably impossible to test this question with numerical accuracy; but the comparative coarseness of the toluol cloud is strikingly manifest to the naked eye. The case is, as I have said, representative.
In fact, aqueous vapour is without a parallel in these particulars; it is not only the lightest of all vapours, in the common acceptation of that term, but the lightest of all gases except hydrogen and ammonia. To this circumstance the soft and tender beauty of the clouds of our atmosphere is mainly to be ascribed.
The sphericity of the cloud-particles may be immediately inferred from their deportment under the luminous beams. The light which they shed when spherical is continuous : but clouds may also be precipitated in solid flakes; and then the incessant sparkling of the cloud shows that its particles are plates, and not spheres. Some portions of the same cloud may be composed of spherical particles, others of flakes, the difference being at once manifested through the calmness of the one portion of the cloud, and the uneasiness of the other. The sparkling of such flakes reminded me of the plates of mica in the River Rhone at its entrance into the Lake of Geneva when shone upon by a strong sun.Proceedings of the Royal Society, vol. xvii. p. 317.
Clouds are so often referred to in these pages that I thought it might be of interest to note the latest remarks on their formation.