a name given to some very extensive fields of ice among the Alps.—Mr Coxe observes of these mountains in general, that they are composed of many parallel chains, the highest of which occupy the centre, and the others gradually diminish in proportion as we recede from thence. The central chain appears covered with pointed rocks; all parts of which, that are not absolutely perpendicular, lie hid under perpetual snow and ice even in summer. On each side of this ridge are fertile and cultivated valleys, interperled with numerous villages, and watered by numerous streams. The elevated peaks of the central chain are covered with snow; but their declivities, excepting those that are extremely steep, have all a covering of ice as well as snow; the intermediate parts being filled with vast fields of ice, terminating in the cultivated valleys above mentioned. The same phenomena, though on a smaller scale, occur in those chains that are at a distance from the principal one: in those which are most remote, no ice, and scarcely any snow, is observed, unless upon some of the most elevated summits; and the mountains diminishing in height and ruggedness, appear covered with verdure, until at last they terminate in small hills and plains.

Thus the glaciers may be divided into two sorts; one occupying the deep valleys situated in the bosom of the Alps, and distinguished by the name of Ice-valleys; the others are those which clothe the declivities and sides of the mountains. These two kinds of glaciers are distinguished by Mr Coxe into the upper and lower glaciers.

The lower glaciers are by far the most considerable; some of them extending several leagues in length. They do not communicate with each other, as has been generally supposed, few of them being parallel to the central chain; but, stretching mostly in a transverse direction, are bordered at the higher extremity by inaccessible rocks, and at the lower extending into the cultivated valleys. The thickness of the ice varies in different parts. In the glacier des Bois, which extends more than 15 miles in length, and upwards of three in breadth, M. Saussure found it generally from 80 to 100 feet; but he was credibly informed that in some places it was not less than 600 feet, and even more. These vast masses of ice usually rest on an inclined plain; where, being pushed forward by their own weight, and but weakly supported by the rugged rocks beneath them, they are intersected by large crevices, and have an appearance of walls, pyramids, &c. according to the position of the eye in viewing them. In those parts, however, where they lie upon even ground, or such as has only a gentle inclination, the surface of the ice is nearly uniform, the crevices being few and narrow, and the glacier being crossed by travellers on foot without any difficulty. The surface of the ice is rough and granulated, so that people may walk upon it excepting such places as have a steep descent. It is opaque, full of small bubbles about the size of a pea, very porous, and greatly resembles a mixture of snow and water congealed. A vast quantity of stones and earth falls down from the mountains upon the glaciers, and are by them thrown off on each side according to the descent of the ice, as will be afterwards explained. The place on which these rest is more hard and elevated than the rest of the ice, and is very difficult to walk upon; the earth is likewise laid upon them in such regular heaps, that it appears to have been done by art. This collection of earth and stones is termed by the natives the Moraine.

Mr. Coxe, who visited the glacier des Bois, informs us, that the appearance of it at a distance was so tremendous, that it seemed impracticable to cross it. Numerous and broad chasms intersected it in every direction; but entering upon it, the company found that courage and activity were only required to accomplish the task. They had large nails in their shoes and spiked sticks; which on this occasion were found to be particularly serviceable. Having passed the Moraine, and descended upon the glacier itself, they found the ice softened by a warm wind which rendered it less slippery than usual. Having walked across it for about a quarter of an hour, they came again to the Moraine, along which they continued their journey for half an hour, and then entered upon the great body of the glacier. "Here (says Mr. Coxe) it was curious to observe the numerous little rills produced by the collection of drops occasioned by the thawing of the ice on the upper part of the glacier: these little rills hollow out small channels, and, torrent-like, precipitate themselves into the chasms with a violent noise, increasing the body of waters formed by the melting of the interior surface, and finding an outlet under the immense arch of ice in the valley of Chamouni, from which the Arveron rushes." As our traveller proceeded on his journey, he was surprized by the noise of a large fragment of rock which had detached itself from one of the highest needles, and bounded from one precipice to another with great rapidity; but before it reached the plain, it was almost reduced to dust. "Having proceeded about an hour (says he), we were astonished with a view more magnificent than imagination can conceive: hitherto the glaciers had scarcely answered my expectations, but now they far surpassed them. Nature had clad herself in all her terrors. Before us was a valley of ice 20 miles in extent, bounded by a circular glacier of pure unbroken snow, named Takul, which leads directly to the foot of Mont Blanc, and is surrounded by large conical rocks, terminating in sharp points like the towers of an ancient fortification; to the right rose a range of magnificent peaks, their intervals filled with glaciers; and far above the rest, the magnificent summit of Mont Blanc, his highest point obscured with clouds. He appeared of such immense magnitude, that, at his presence, the circumjacent mountains, however gigantic, seemed to shrink before him, and hide their diminished heads. In half an hour we arrived at the Moraine, which forms a boundary of the valley, crossed it, and proceeded upon a body of ice about three quarters of a mile broad. Here the ice was more even and free from chasms than in the great valley. We then passed a second moraine, and beyond that another mass of ice to a third moraine: descending from thence we came upon the last ridge of ice, broader considerably than the two former, and full of large chasms: it is separated from the rock only by a very narrow moraine. These moraines contain great quantities of crystal."

They continued to ascend the valley of ice, the scene constantly increasing in magnificence and horror; and having walked about five miles on the ice, they arrived at last at the foot of the eminence named Couvercle, where they were obliged to quit the ice. The doing this was extremely dangerous, and at one place very tremendous. It was a bulging smooth rock, with a precipice of considerable depth terminated by a vast crevice in the ice, which seemed to stop all further progress: a small hollow in the middle, however, afforded room for one foot; and having fixed this, they sprung over to the other side, being helped and directed by the guides who went over first. Having gained the top of the Couvercle, they had a view of three of the glaciers, viz. that of Talefre to the left, l'Echau in front, and Takul on the right; all uniting in that great one called the Glacier de Bois. The Couvercle itself is a most extraordinary rock, having the appearance of a large irregular building with many sides; the substance of which is granite. Having reached the top, they were surprized with a thunder-storm, from whence they took shelter under an impending rock. The view was exceedingly magnificent; the glaciers appearing like a rugged expanse of frozen sea bounded by gigantic rocks, and terminated by Mount Blanc. A single rock appeared of a triangular figure, covered with Alpine plants; and which, by reason of its contrast with the rugged and snowy mountains in the neighbourhood, has obtained the name of the Garden.—During this, as well as other excursions among the Alps, Mr. Coxe had occasion to observe that the colour of the sky was of a much deeper blue than in the lower regions.

The upper glaciers may be subdivided into those which cover the summits, and those which extend along the sides of the Alps. Those on the very summits, however, though they have the appearance of ice, are not so in reality, but consist entirely of snow hardened by the extreme cold. M. Saussure found that which covered the top of Mount Blanc to be penetrable, though with difficulty, by a stick; but below this hard crust was a soft snow without coherence. The sides are covered with a mixture of ice and snow; by reason of the superior power of the summer sun to dissolve the snow, which afterwards congeals into hard ice.

Several conjectures have been made concerning the formation of these extraordinary bodies of ice. Mr. Coxe agrees with M. Gruner in opinion, that they are produced by the continual dissolution of the snow in summer, and its congelation by the succeeding frosts. Hence, on the summits of the mountains where the sun has very little power, the glacier is loft, and contains no ice: as we descend the mountains the confidence becomes firmer, because there is a considerable mixture of snow-water, the congelation of which augments the hardness; and in the valleys, the glacier is hardest of all, because the portion of water is there much superior to that of the snow. Hence it seems plain that the glaciers derive their origin from the melting of the snow on the upper parts of the mountains, and the congelation of the water as it advances: and to this cause M. Saussure adds the quantity of snow which often rolls down into the valleys and congeals along with the water just mentioned. Another question concerning the glaciers naturally occurs, namely, Whether they are to be considered as in a state of increase or diminution? Mr Coxe is of opinion, that they occasionally increase and decrease; in proof of which he adduces the following observation.

"The borders of the glacier of Montanvert are mostly skirted with trees: towards its base a vast arch of ice rises to near 100 feet in height; under which the river Arveron rushes with considerable force, and in a large body of water. As we approached the ice, we passed through a wood of firs: those trees which stand at a little distance from the arch are about 80 feet high, and are undoubtedly of a very great age. Between these and the glacier the trees are of a later growth; as is evident from their texture and inferior size. Others, still smaller, have been overturned and enveloped in the ice: there seems to be a kind of regular gradation in the age of these several trees, from the largest which are standing, to the smallest that lie prostrate." — Hence our author concludes, that the glacier once extended as far as the row of small firs; but that, upon its gradual dissolution, a number of trees shot up on the spot it had occupied; since which time the ice has again advanced, and overturned the last grown trees before they had attained to any considerable height. — This he thinks also confirmed by the following fact. — "Large stones of granite are usually found at a small distance from the extremities of the glacier. These stones have certainly fallen from the mountains upon the ice; have been carried on in its progress; and have tumbled into the plain upon the dissolution or sinking of the ice which supported them. These stones, which the natives call Moraine, form a kind of border towards the foot of the valley of ice, and have been pushed forward by the glacier in its advances: they extend even to the place occupied by the larger pines."

In opposition to those who maintain that there is a constant accumulation of ice and snow in the Alpine regions, our author makes the following remarks.

1. Between the years 1776 and 1785 the glacier of Grindelevald had diminished to such a degree, that the spot which its extremity occupied in the former year, was at least 400 paces from that occupied by it in the latter. 2. In the year 1785 the Murailles de Glace, which in 1776 he had described as forming the border of the glacier of Boffon, no longer existed; and young trees had shot up in the parts which were then covered by the glacier of Montanvert. Still, however, it may be urged, that these changes only take place in the valleys where the power of the sun is considerable; and that from thence we cannot form any adequate idea of what passes in the more elevated regions, where in all probability more snow falls than can be dissolved. In support of this opinion, it is alleged, that the cold produced by the mass of ice already formed ought to augment it still more; and that, within the memory of the present generation, many places have been covered with ice which were not so before. To these arguments, however, Mr Coxe replies, that the causes, which diminish the ice in the upper regions, are no less powerful than the cold which tends to augment it. There are, 1. Rain or sleet; which falling upon the lower glaciers, thaw the ice, increase the rills on its surface, excavate channels, and in many ways tend to diminish its quantity. 2. Evaporation, which takes place even from the surface of the ice itself, acts still more powerfully; and its action is not confined to any particular season. 3. The falling of the snow and ice; both that which comes gradually from the clouds, and which descends from the mountains in great masses, called by the natives avalanches. When these last fall down into milder regions, though sometimes they resist the influence of the sun and form ice-valleys, yet they generally dissolve. They are most common in the upper glaciers, though sometimes they descend upon the lower, while the gradual descent of snow from the clouds, which chiefly takes place in the lower, contributes very much to lessen the mass. 4. All the lower glaciers or valleys of ice rest on an inclined plane, are hollow, and undermined by torrents which are constantly flowing from the upper glaciers, as well as from their own lowermost surface. Their foundation being thus constantly diminishing, the lower glaciers are carried imperceptibly forward into the cultivated fields, where an end is necessarily put to their progress by the heat of the sun. Hence we may see the reason of that strange phenomenon taken notice of by Mr Coxe, that with one hand he could touch ripe corn, and with the other hold ice. This descent of the glacier is demonstrable from the trees overturned by it, and the morain always observed at the bottom of the lower glaciers. 5. The heat of the sun is an evident cause of the diminution of the glaciers. To this Mr Coxe adds another cause less generally known, viz. the warm winds which blow by night as well as by day both in the upper and lower glaciers. "These warm winds (says he) are during summer so common in those parts, that I never crossed a glacier without feeling in some particular positions a warmth similar to the air of a hot bath." 6. Another cause is the mean temperature of the earth itself; which, where it is not exposed to the piercing cold of the atmosphere, is found to have a temperature always above the freezing point. As the vast thicknesses of the superincumbent ice, therefore, is in the present case abundantly sufficient to prevent the access of the atmosphere, it is plain that the lower surface of it must, by being in contact with the earth, continually decay. With regard to the other argument drawn from the known increase of the ice in some places, Mr Coxe does not deny it; but infers, that there is no continual increase of the whole, but that if it increases in some places, it diminishes in others; and his opinion in this respect was confirmed by those who frequent the mountains.