ment of Porter, true in 1820, ceased to be so nine years afterwards. Professor Parrot in 1829 effected the ascent of Ararat, and in 1834 the mountain was again scaled by M. Autonomoff, in order to vindicate the reputation of the Prussian traveller, whose veracity had been called in question by the Armenian ecclesiastics, and the American missionaries Smith and Dwight. Its height is given at 17,260 feet, which exceeds by 1528 feet the highest elevation of Europe; but the table land of Armenia, from which it rises, is stated by Ritter to be 7000 feet above the level of the sea. There is a far greater elvation attained by some of the Himalayah Mountains, which separate the valleys of Cashmere from Thibet, and present the loftiest projections to be found upon the terrestrial surface. On the west, Javaher rises to the height of 25,746 feet, and on the east, Dhwalagiri, to 27,737 feet above the sea. The highest summit on the new continent was once supposed to be Chimboraço, in the Andean chain, and likewise the greatest altitude on the surface of the globe, but it is now deprived of the distinction. Though 21,440 feet above the level of the ocean, and one of the grandest objects in the great American range, it is lower by nearly the whole height of Vesuvius than the Nevada di Sorata, in the eastern cordillera of Peru. Our own Ben-Nevis has recently been shorn of a similar honour. Long regarded as the monarch of the British mountains, it is now known to be surpassed in height by Ben-Mac-Dui, in the group of Cairngorm, on the borders of Inverness-shire. The mean height of the Andes, apart from projecting cones, is estimated at 6000 feet in Patagonia, 8000 in Chili, and 15,000 in Peru. The estimated heights of the principal mountains are given in the table below, but a few of these have not been determined with accuracy. A remarkable instance of close approximation in calculating the height of Etna, occurred between independent observers, pursuing different methods, at distinct times, unknown to each other. The Sicilians, vain of their mountain, attributed to it an elevation of 13,000 feet, which Captain Smyth, when surveying in the Mediterranean, reduced by more than 2000, an abridgment which raised no little anger and contention. The result was subsequently verified by Sir John Herschel:-"The height," observes the latter, "of the higher of the two summits of Etna, which I measured barometrically in 1824, came out to be 10,872 English feet above the level of the Sea of Catania. Captain Smyth's result, with which I was not acquainted till long after the calculation of my own, gave 10,874. I have also, somewhere or other, though I cannot lay my hands on it, a memorandum of a zenith distance, observed by Cacciatore, of the summit of Etna, from Palermo ; the result of which, calculated by a terrestrial refraction index, concluded by Cacciatore and myself, from observations by him and myself, on Monte Cuccio, gave a total altitude of Ætna agreeing within a very few feet indeed of the same; so that I have no doubt the above is very good, unless that summit have since been blown up or blown down." It has been imagined that most of these chains are mutually connected, and form one grand consecutive scheme of high lands stretching through the extent of both continents, in the form of a vast irregular arch. Could a spectator command a view of the globe, supposing him to stand in New Holland facing the north, he would see on his right hand a continuous system of high mountains extending along the entire coast of America, linked with Asia by the Aleutian Isles. He would see also a chain on his left hand running along the coast of Africa, passing through Arabia into Persia, mingling there with the range that traverses Europe from the Atlantic, and merging in the mountains of central Asia, which are continued north-easterly to Behring's Straits, and form the spine of the old world. Thus, while these chains of mountains, when viewed in detail, appear isolated and utterly unsystematic, yet when the globe is contemplated upon a grand scale, they seem to constitute one immense range in the form of an irregular curve, with outshoots from it, bounding the bed of the Pacific, on the north, east, and west. In the annexed list, the elevation of several remarkable localities are stated, with some of the highest altitudes occupied by man, and reached by him. Feet. Ascent of Gay Lussac, at Paris, in 1804, being the greatest height ever attained by a balloon 22,900 19,400 21,000 Absolute height of a village in the Himalaya, visited by Gerard, perhaps the highest inhabited spot on the globe 13,500 Greatest altitude of the peach, apricot, and walnut growing luxuriantly in the Himalaya Thick woods of pines and birch trees in the Himalaya, the latter attaining a large size 14,000 17,000 Elevation of the city of Mexico Highest pass in Europe, that of the Cervin, over the Pennine Alps Highest constructed road in Europe, the pass of the Ortler Spitz Feet. Absolute elevation of poplars found by Gerard in the Himalaya, twelve feet in girth 12,000 Contemplating the projections of the surface with reference to their absolute elevation above the level of the sea, some of them appear protuberances of enormous bulk, and we are apt to imagine that they must detract largely from the regularity of the earth's spherical form. But they become insignificant when compared with the volume of the globe itself, the highest eminence, that of between five and six miles, being only about 8 of the semidiameter of the sphere. They bear therefore much the same proportion to the terrestrial spheroid as the little risings on the coat of an orange to the fruit. Books of travels abound with conflicting statements respecting the distance from which particular mountains may be seen. The length of the line of visibility is not only influenced by conditions of the atmosphere, but by the character of projections, apart from their height. The Peak of Teneriffe is not so frequently visible at the same distance as those tops of the Andes which are of corresponding elevation, not being, like them, invested with perpetual snow. Humboldt remarks, that the cone of the former, no doubt reflects a great degree of light on account of the white colour of the pumice with which it is covered; but its height does not form a twenty-second part of the total elevation, and the sides of the mountain are coated with blocks of dark-coloured lava, or with luxuriant vegetation, the masses of which reflect little light, the leaves of the trees being separated by shadows of greater extent than the illuminated parts. He refers therefore the Peak to that class of mountains which are seen at a great distance only in a negative manner, or because they intercept the light transmitted from the extreme limits of the atmosphere. Still, it has been observed at the distance of 124, 131, and even 138 miles; and the summit of Mowna-Roa in the Sandwich Islands has been seen, at a period when it was destitute of snow, skirting the horizon from the distance of 183 miles. This is the most remarkable example yet known of the visibility of high land, and as Mowna-Roa was negatively seen, both cases refute the theory of Bouguer, that mountains seen negatively cannot be perceived at distances exceeding 121 miles. The summits of the superior elevations are regions of perpetual snow and ice, and below the limits of constant congelation there is a zone in which snow lies upon the surface through the greater part of the year. The accumulations above and near the line where perpetual frost commences, constitute some of the most dangerous and terrible phenomena of high mountain districts. When the mass becomes so great that the inclined plane on which it rests can no longer support it, or when the pile which has been heaped together by the winter snow-storms becomes loosened by the action of the sun in spring and summer, it descends with immense violence from its site into subjacent valleys, sometimes filling them up with its volume, and burying man, beast, and village beneath its load. The avalanches composed simply of drifts, are not so dangerous and destructive as those of snow rendered clammy by a thaw. The former may frequently be removed without much damage being sustained, but the latter are precipitated in compact masses, and carry away or crush the objects that lie in their path. In the canton of the Grisons, an avalanche descended in the year 1749, upon the valley of Tawich, and entirely covered the whole village of Rueras. The snow torrent fell in the night without disturbing some of the inhabitants, who, on awaking in the morning, were surprised that the day did not break ;-sixty out of a hundred persons were rescued from their perilous situation alive, a sufficient quantity of air to support life being obtained through interstices in their snowy canopy. In the same canton, an avalanche descended upon Val Calanca in 1806, which removed a forest from its site to an opposite side of the valley, and fixed a fir-tree upon the roof of the parsonage house. Avalanches occur in the Pyrenees and in Norway, but are most frequent in the high Alps owing to their abrupt and precipitous declivities. They are often set in motion by vibrations of the air, such as the discharge of a musket, or a peal of thunder, or the mere passage of a traveller will produce it; and hence in districts subject to them a cautious silence and wary footsteps are enjoined upon the inexperienced visitor. Professor Forbes gives a striking instance of encountering a highly electrical condition of the atmosphere, when at a considerable elevation in the Alps: "We were still above 9000 feet above the sea, when I noticed a curious sound which seemed to proceed from the Alpine pole with which I was walking. I asked the guide next me whether he heard it, and what he thought it was. The members of that fraternity are very hard pushed indeed, when they have not an answer ready for any emergency. He therefore replied with great coolness, that the rustling of the stick proceeded from a worm eating the wood in the interior. This answer did not appear to me satisfactory, and I therefore applied the experimentum crucis of reversing the stick, so that the point was now uppermost. The worm was already at the upper end. I next held my hand above my head, and my fingers yielded a fizzing sound. There could be but one explanation— we were so near a thunder cloud as to be highly electrified by induction. perceived that all the angular stones were hissing round us like points near a powerful electrical machine. I told my companions of our situation, and begged Damatter to lower his umbrella, which he had hoisted against a hail shower, and whose gay brass point was likely to become the paratonnerre of the party. The words were scarcely out of my mouth when a clap of thunder, unaccompanied by lightning, justified my precaution." | The thunder clap, the hunter's horn, or even the human voice, has frequently shook the nicely poised avalanche from its site, and hurled it into lower regions, crushing trees, sweeping away rocks, and damming up the streams that have lain in its course. I soon Besides accumulations of snow, we meet with glaciers in high regions, or extensive i fields of ice. These are formed of avalanches partially thawed during the heat of summer. The water yielded by the melting of the surface, in connection with rain, percolates through the mass, which acquires consistency, and is converted into eternal ice by the frost of a following winter. Iceland is appropriately named from the number and extent of its glaciers, which are there known by the name of Yokuls, signifying large masses of ice. The most extensive, the Klofa Yokul, in the eastern quarter of the island, is a vast chain of ice and snow mountains, supposed to fill a space of not less than three thousand square miles. Some of the Yokuls are remarkable for their vacillation, not remaining in a settled position, a peculiarity common to the Alpine glaciers, These ice formations are found among the Norwegian highlands, in the chain of the Pyrenees, upon the Sierra Nevada of Spain; but their grand European site is the Alps. "If," says Saussure, a spectator could be placed at a sufficient height above the Alps, to embrace at one view those of Switzerland, Savoy, and Dauphiné, he would see a mass of mountains intersected by numerous valleys, and composed of several parallel chains, the highest in the middle, and the others decreasing gradually as they recede. The central and highest chain would appear to him bristled with craggy rocks, covered, even in summer, with snow and ice in all those places that are not absolutely vertical; but on both sides of the chain, he would see deep and verdant valleys, well watered and covered with villages. Examining still more in detail, he would remark that the central range is composed of lofty peaks and smaller chains, covered with snow on their tops, but having all their slopes that are not very much inclined, covered with ice, while the intervals between them form elevated valleys filled with immense masses of ice, extending down into the deep and inhabited valleys which border on the great chain. The chain nearest to the centre would present to the observer the same phenomenon, but on a smaller scale, beyond which he would see no more ice, nor even snow, save here and there on some of the more elevated summits." Saussure therefore recognised two kinds of glaciers; the first contained in the valleys, more or less deep, and which, though at great elevations, are still commanded on all sides by mountains higher still; the second not contained in valleys, but spread out on the slopes of the higher peaks. The glacier system of the Alps embraces an extensive area. M. Ebel estimates, that there may be at least four hundred of the larger sized glaciers, or varying from three to thirty miles in length. The aggregate superficial extent of all those of the Tyrol, Switzerland, Piedmont, and Savoy, is calculated by some authorities to amount to not less than fourteen hundred square miles. The greatest breadth of an individual specimen is seldom more than two miles. The thickness varies from a hundred to six hundred feet. The glaciers are moving masses, slipping down the inclined planes upon which they are situate by the impulse of their own gravity, when their adhesion to the surface of the earth has been weakened by the heat of summer. This motion gives rise to the extraordinary spectacle, of summer productions and winter formations being sometimes in immediate contact with each other, the ice-fields obtruding into flowery meadows, and gradually forcing their way into the regions of cultivation. According to Professor Forbes, the very huts of the peasantry are sometimes invaded by this moving ice, and many persons now living have seen the full ears of corn touching the glacier, or gathered ripe cherries from the trees with one foot standing on the ice! The rate of advance of different glaciers varies considerably. M. Ebel states, that in the valley of Chamouni, they travel at about fourteen feet a year, while in that of Grindelwald, the glaciers move rather faster, at the rate of twenty-five feet in a year, a difference probably attributable to the ground being variously inclined. The same glacier will also make more progress in one year than in another, according as a summer of lesser or greater warmth renders its liberation more or less complete. Captain Hall remarks upon the ploughing up of the ground lying before a glacier by its snout as an obvious proof of its progression, and instances the remarkable case of the glacier of Brenva falling into the lower part of the Allée Blanche, fairly crossing from one side of the valley to the other, and being so irresistibly pressed forward by the weight of snow on its shoulders, high up the sides of Mont Blanc, that on reaching the opposite side of the valley, it actually travels for a considerable distance up the bank. "The guides," he remarks, "pointed out the corners of green fields, peeping out from the sides of the glacier in the middle of the valley, and showed us traces of walls and fences which had belonged to large villages, now entirely obliterated by the moving mass. I took notice of one circumstance, which told the fatal story very well. We had walked along a well-worn footpath till our course was abruptly stopped by the edge of the glacier; but on crossing over it, we re-discovered |