He began with some notices as to the characteristics of the atmosphere and the land in West Greenland and Spitzbergen. The atmosphere is remarkable for darkness of colour and density, for the production of highly crystallized snow, and for almost instantaneous changes from perfect calm to impetuous storm. The land is remarkable for abrupt precipices, rising directly from the ocean to a great height: the dark-coloured rocks contrasted with the snow of the purest whiteness with which they are capped, produce a very striking effect. Here the white bear is the lord of the creation: seals and all other animals flee his presence. He is yearly attracted over the ice to the fishing ground, by the carcases of whales, the smell of which he seems to perceive at a wonderful distance.

As to the ice, Mr. Scoresby remarked that Davis Straits is noted for enormous ice-bergs or ice-islands, and that Greenland is more remarkable for ice-fields. Some of these ice-fields are of vast extent, perhaps 100 miles long and 50 broad; the surface being raised from 4 to 6 feet above the water, and the base sunk near 20 feet below the water. The ice-bergs of Baffins Bay are sometimes nearly two miles long and perhaps 100 feet high, while their base must reach 450 feet below the surface of the water. Some icebergs are formed on the land; but the most huge are, in Mr. Scoresby's opinion, produced in the deep sheltered bays of the sea, and formed partly of sea water and partly of snow and sleet, yearly accumulated perhaps for successive ages.

Mr. Scoresby mentioned, that he never could, by experiments made in Greenland, obtain from sea water, ice that was either compact, transparent, or which yielded a fresh solution. Yet freshwater ice is common, and the whale-fishing ships frequently water at some pool on the surface of an ice-berg. Salt-water ice is soft,' porous, white; it is lighter than the other, its specific gravity beingabout 0873, while that of fresh-water ice is 0937. This last has a black appearance while floating in the sea, and is transparent, with a green hue, when held in the air. Its edges are sharp like glass. With pure pieces of this kind of ice Mr. Scoresby sometimes amused himself in forming lenses, with which he was able to fire gunpowder, light the sailors' pipes, burn wood, and even melt lead.

Ice is generated in the Northern Ocean entirely independent of the vicinity of land. It is formed even in rough seas during intense cold; first producing what is called by the sailors sludge, and then flat pieces of a rounded shape, and turned up at the edges, which have received the whimsical name of pancakes. In the sheltered openings which occasionally occur in the great fields of ice, bay-ice is often rapidly formed: it will bear a man's weight in 48 hours, and in a month is fully a foot thick. Suppose a large opening to be thus frozen over, and cemented on every side to the older ice, a great basin or hollow is produced: this becomes a receptacle for snow: next summer the snow is melted, and during the following winter the water is converted into a solid layer of fresh-water ice,

In this way, Mr. Scoresby thinks, the most compact field-ice may be generated in a few years. Other fields are formed of boards of packed ice cemented by frost. Ice-fields have an invariable tendency to drift to the south-westward, amid various or contrary winds. They appear in June in the fishing latitudes, and many are yearly broken up by the agitation of the waves when they advance to the open ocean. When two fields come in contact, the

concussion is tremendous.

Mr. Scoresby gave a description of the present situation or boun daries of the circumpolar ice, both in close and in open seasons,which it is impossible to abridge. Such is the outline, that when the ice touches the south point of Spitzbergen, a barrier is formed against access to the open sea farther north, where whales are to be found. If this barrier consist only of packed ice, and be not cemented into fields, the ships are forced through it, with great difficulty no doubt, and not without peril. In June this barrier divides in the middle, and when the vessels return from the fishing it frequently happens that no vestige of it is to be seen. The largest fields of ice are always moving and changing place, generally drifting to the south-west, although, on account of their vast extent, it is difficult to estimate the amount of the change. A ship beset in a field was carried, with a semicircular sweep, between fifteen and twenty leagues in fifty hours. Two ships embayed in packed ice, within a few furlongs of each other, were separated to the distance of some leagues in the course of two days, and yet the continuity of the pack of ice appeared to the eye to have remained unbroken.

The effects of the ice on the atmosphere are very striking. A strong gale blowing against one side of a large field, is so moderated in its passage over the ice, that it is scarcely felt on the other side. Moist and temperate gales from the southward, on reaching the fields, immediately discharge their superfluous moisture in the form of snow. The ice-blink is a curious phenomenon. The rays of light which fall on the ice are reflected, while those which fall on the water are in a great measure absorbed. A luminous belt appears in the horizon, containing a beautiful map of the ice, sometimes so perfect that a practised eye can determine whether field ice or packed ice be represented.

In the last part of his paper Mr. Scroresby treated of the practicability of reaching the North Pole, by setting off from the north of Spitzbergen, and travelling over the ice. That this may not be met with a smile of contempt, we may mention that his reasonings, and the statements founded on his own experience, went great way in removing the objections of some of the most distinguished Scottish philosophers. Mr. Scroresby has been several times beyond 80° N. lat. Indeed, he on one occasion made a nearer approach to the polar point than any other scientific observer. Captain Phipps (Lord Mulgrave) in 1773 reached 80° 37′; but in1806 Mr. Scoresby (then acting as chief mate to his father, well

known as one of the most enterprizing and intelligent captains in the Greenland trade) penetrated as high as 814° N. a distance of only 170 leagues from the pole. Even when north winds had prevailed for days, Mr. Scoresby did not find the cold of 80° much different from that of 70° N. With woollen clothing, therefore, he thinks the cold would not be overwhelming, and an external garment of varnished silk would protect the body from moisture. It would be impossible to accomplish a journey of 1200 miles (600 going and 600 returning) without the assistance of some fleet quadrupeds accustomed to harness. Rein-deer or dogs are the only animals that could be employed, and they must be procured from the countries where they are trained. Dogs are most hardy and tractable, and would on the whole be preferable. Drivers must also be procured from the same countries. The sledges must be light, and in the form of boats, in case of spaces of open water occurring. Between a month and six weeks, Mr. Scoresby thinks, would suffice for the journey. To avoid the retarding effects of soft snow, he suggests that the party should set out by the close of April. When the aid of the magnetic needle as a director should be lost, by its pole being directed to the zenith, the sun would be the only guide. A chronometer would be an indispensable instrument. With a chronometer adjusted to the meridian of north-west Spitzbergen, the bearing of the sun at the time of noon (provided this could be accurately ascertained very near the pole) would afford a line of direction for the return; the position in regard to longitude being corrected twice a day. White bears are the only living enemies to be expected; but they are not likely to occur in numbers very far north, as their food must necessarily be scarce. Mr. Scoresby has little expectation of mountainous land occurring, and he thinks it highly improbable that the sea will be found free from ice at the pole, as the Dutch navigators have asserted it to be. Mr. Scoresby's ample experience convinces him, that thick weather is only to be dreaded as the accompaniment of southerly winds, which occur but seldom and at distant intervals.-Such a journey must necessarily be hazardous; but great difficulties have in former times been overcome in travelling the northern ice. In the Spring of 1715,Alexei Marcoff, a Cossack, travelled from Siberia, in a sledge drawn by dogs, near 400 miles northward, over a surface of packed ice. He was obliged to stop about the 78th degree, on account of the provisions for his dogs falling short; by killing some, and feeding the others with the carcases, he effected his return in safety. But if the party were to reach the pole either by means of rein-deer or dogs, and these entirely to fail through cold and fatigue, it is at least possible that they might be able to accomplish their return on foot, drawing their provisions in a sledge; a large party of the crews of the Dutch Greenland fleet wrecked in 1777 having traversed the ice for a hundred leagues, amid the severity of the arcticwinter, and actually reached the settlements of the Danish missionaries, without any suitable preparations for such a journey. VoL. VI. N° II.

K

ROYAL INSTITUTE OF FRANCE.

Account of the Labours of the Class of Mathematical and Physical Sciences of the Royal Institute of France during the Year 1814.

I. Physical Department. By M. le Chevalier Cuvier, Perpetual Secretary.

More than a hundred years ago there had been extracted from the quarries of Eningen, near the lake of Constance, a petrified skeleton, which Scheuchzer, a naturalist of Zurich, had taken for that of a man, and which he had engraven under the title homo diluvii testis. More recent naturalists had considered it as the skeleton of a fish. M. Cuvier, from the simple inspection of the figure published by Scheuchzer, had considered it as an unknown and gigantic species of salamander. Having made a journey to Harlem, where this celebrated fossil is deposited in the Teylerian Museum, and having obtained permission from M. Van Marum, Correspondent of the Class, and Director of that Museum, to dig into the stone in order to expose those parts that had been hitherto concealed, M. Cuvier discovered feet, with their bones and toes, small ribs, teeth along two large jaw-bones; in short, all the characteristic parts; so that it is now no longer possible to doubt that the skeleton really belonged to a salamander. He has shown to the Class a figure of this fossil thus exposed, which he means to send, together with a description, to the Academy of Harlem.

The same member has exhibited a head of the last animal, called palæotherium medium, recently disengaged from the gypsum of Montmartre. This head was complete, and confirmed all the conclusions hitherto drawn from isolated fragments.

M. de Humboldt, Foreign Associate, has communicated the truly astonishing history of the volcano of Jorullo, which burst out in 1759 at Mexico, on a well cultivated platform, where two rivers of cold water flowed, and where, during the memory of man, no subterraneous noise had been heard. The catastrophe was announced. some months beforehand by earthquakes and bellowings, which continued 15 or 20 days. A shower of ashes then fell, and more violent bellowings took place, which induced the inhabitants to fly; flames arose over an extent of more than half a league square; pieces of rock were thrown up to a great height; the crust of the earth rose and sank like the waves of the sea; there arose an innumerable multitude of small cones, from six to nine feet high, which covered the surface of the platform, and which still remain there. Finally, there arose in the direction of S. S. E. and N. N. E. six hills, the principal of which, still distinguished by a burning crater, is not less than 1600 feet in height. These frightful operations of

Nature continued from the month of September, 1759, till next February. Eye-witnesses declare that the noise was equal to what would have been produced by thousands of cannon, and that it was accompanied by a burning heat, part of which still continues; for M. de Humboldt found the heat of the soil 36° Fahr. higher than that of the atmosphere. Every morning thousands of columns of smoke rise from the cones and the crevices of that great platform. The two rivers now contain hot water impregnated with sulphureted hydrogen; and vegetation is only beginning to appear upon this shattered country.

This volcano is 46 leagues from the sea, and nearly as far from the nearest active volcano. On this occasion M. de Humboldt remarks that several volcanoes of the New World are at as great a distance from the sea as this is; while in the Old World we know no volcano that is 12 leagues distant from the sea, and the greater number are upon the shore. This scientific traveller informs us, likewise, that all the great volcanoes of Mexico are found not merely in almost the same line transversal to the direction of the Cordileyras, but likewise within a few minutes of the same parallel, as if they were all elevated above a subterraneous crevice which extends from sea to sea. He ascertained all these facts by measures and determinations of positions, as exact as troublesome to take. The public will see the whole details in the continuation of the celebrated work in which M. de Humboldt has consigned the result of his great work on America.

M. de Humboldt, in a memoir on vegetation in the Canary Isles, has stated some general considerations on the geography of plants. By combining the results of observation with the double influence which the latitude and the height in the atmosphere produces on the temperature, he has fixed for a certain number of points the limits of perpetual snow, the mean temperature of the air at that limit taken during the whole year, and likewise the particular temperature of the winter and summer months; and he has shown that we may deduce from these different data the habitual distance between that limit and the heights on which trees and corn grow; and that even the variations, apparently capricious, which the same species of trees present in different climates, may be explained when we join to these data the consideration of the period of the year when each tree increases in bulk.

It has been long known that the number of stigmata is not constant in the family of cypere; nor was it believed that these variations were sufficiently important to serve as a basis for the distinction of the genera.

M. Schkuhr, a German botanist, first observed that in the genus of carex there exist species with two and three stigmata, and that the number of these organs is always the same as that of the angles of the fruit.

Our associate, M. the Baron de Beauvois, has generalized this observation to all the plants of the family. He has remarked some