fibres, and it was for the purpose of ascertaining the best and most effectual means of employing them, that Saussure's experiments were made. But to attain this object, it was also necessary to examine all the possible combinations of water and air, and the influence which they experience on the application of heat and pressure; to produce, by artificial means, the maximum of humidity and the maximum of dryness; and to determine the influence which humidity exercises in its turn upon the expansion of the air and the manifestation of heat. From these experiments we therefore see an almost new science springing up, and Meteorology beginning to possess rational principles.

Saussure made choice of hair as the hygroscopic substance, possessing most sensibility and regularity. This result of his comparisons has been disputed; but what could neither be cavilled at, nor attacked, were his beautiful observations on the expansion of air in proportion as it is charged with humidity; on the relations of humidity with pressure; on the nature of the vesicular vapours or fogs which are suspended in the air like so many small balloons; and on many other points, all more or less new to science, at the period when he published this work.

Time does not permit us to lay before you the numerous mechanical details by which he at length rendered his hygrometer and other instruments capable of convenient use, while, at the same time, he gave them the necessary precision. It is sufficient to observe, that, in all these investigations, we discover a mind no less accurate than fertile in resources, and calculated to be the model of natural philosophers as much as that of naturalists.

Although Saussure had travelled for twenty years among the mountains; had fourteen times crossed the Alps, by eight different routes; had made sixteen excursions to the centre of that chain; although he had traversed the Jura range, the Vosges, the mountains of Switzerland, Germany, Italy, Sicily, and the adjacent Isles, and had visited the extinct volcanoes of France; yet had he never reached the summit of Mont Blanc, which he beheld every day from his window. Ten times he had attacked it, as it were, by all the valleys which terminate on its sides; he had gone round it, examined it from the summits of the neighbouring mountains, but had always found it inaccessible. On the 18th August 1787, he learned that two

inhabitants of Chamouny, by following the most direct route, which various prejudices had hitherto made him shun, had returned the previous day from that summit which mortal foot had never before trodden. His eagerness to follow their steps may be easily imagined, when, on the 19th August, he was at Chamouny; but the rains and snows prevented him from ascending that year. It was not till the 21st July 1788 that he at length accomplished this great object of his wishes.

Accompanied by a servant and eighteen guides, whom he encouraged by his promises and example, after having ascended for two days, and lain two nights in the midst of the snows, -after having viewed horrible chasms under his feet, and heard two tremendous avalanches roll by his side, he arrived at the summit about the middle of the third day. His eyes, he says, were first turned towards Chamouny, where his family were watching his progress with a telescope, and where he had the pleasure to see a flag waving in the air, the appointed signal to assure him that his arrival had been perceived, and that their painful solicitude respecting his fate was at least suspended. He then calmly set about performing his intended experiments, and continued for several hours at this employment, although, at the height he now stood (15,000 French feet), the rarity of the air accelerated the pulse like a burning fever, and overwhelmed them with fatigue at the slightest motion, while, in those frozen regions, a cruel thirst parched their lips, as if among the sands of Africa; and the snow, by reflecting the light, dazzled the sight, and scorched the face. The inconveniences of the poles and tropics were alike experienced; and Saussure, in a journey of a few miles, braved as many hardships and dangers, as if he had gone round the world.

His last expedition, and one of the most interesting with regard to the theory of the earth, was that to Mount Rosa in the Pennine Alps, which he performed in 1789. Instead of those needles of granite, which commonly pierce their envelopes, to form the ridge of the high Alps, he there observed an enormous plateau, where the granite, which every where else appeared uncovered, was enveloped under a mass of slate and limestone, disposed, along with the granite, in horizontal strata. From this appearance the views of Saussure, regarding the formation of granite in a fluid, and the succession of the other pri

mitive deposites, which preceding observations had long before established, were now invincibly confirmed.

Thus, every step that he advanced among the mountains discovered to him some new truth, and either enabled him better to arrange the series of those he already possessed, or to fill up some void in it. It would be interesting to trace all the metamorphoses which the system of his ideas had undergone; but time does not permit. Let us content ourselves with drawing a brief sketch of the principal acquisitions to the theory of the earth, which result from a concluding analysis of his works. He destroyed the idea, which had been very prevalent until his time, of a central fire, a source of heat situated in the interior of the earth. His experiments even prove that the water of the sea and of lakes is colder in proportion to the depth from which it is taken. He proved that granite was the oldest primitive rock, and that which serves as a basis to all the others; he shewed that it was disposed in strata, and formed by crystallization in a fluid, and that if its strata are at the present day almost all vertical, this position is owing to a posterior revolution. He proved that the strata of the lateral mountains are always inclined toward the central chain, namely, the granite chain; and that they present their precipices to this chain, as if they had been broken upon it. He ascertained that the mountains are the more rugged, and their strata depart the more from their horizontal line, in proportion to the antiquity of their formation. He shewed, that, between the mountains of different orders, there are always heaps of fragments, rolled stones, and all the other indications of violent convulsions. Lastly, he pointed out the admirable contrivance, which supplies and renews among the snows of the high mountains, the reservoirs necessary for the production of large rivers.

Had he only bestowed a little more attention on petrifactions, and their positions, it might have been said, that we owed to him all the foundations on which geology has hitherto been built; but, incessantly occupied with the great primitive chains, and the terrible catastrophes that must have taken place to have overturned their enormous masses, it would appear that he had formed a somewhat erroneous idea of those lesser mountains or hills whose repose had not been disturbed, and which contain remains of the newest epochs of the history of the globe.

Possessed of materials so numerous and important, it must have required a powerful effort to resist the temptation of forming a system. Saussure, however, had this firmness of resolution; and we shall make it the last and the principal trait in his eulogy. His mind was of too elevated a character not to take a prospective grasp, in some measure, of the whole field of the science, and not to perceive to what extent it was imperfect, notwithstanding all the facts with which he had enriched it; and it was, therefore, by pointing out what still remained to be investigated that he terminated his labours. So noble an example has not deterred his successors from drawing up, as formerly, the most romantic systems; but this is only an additional reason for paying our tribute to a mind so rare.

Saussure still seemed young enough to collect a portion of the observations which were awanting to the science; but a disease, the germ of which had perhaps originated in the fatigues of his journeys, began, a little after his fiftieth year, to undermine his constitution. It was increased by some embarrassments of fortune, occasioned by the French revolution. Three successive attacks of paralysis reduced him to great weakness, and, on the 22d January 1799, after four years of sufferings, he died, aged only 59 years.

Equally beloved and honoured as Bonnet by his fellow citi zens and by strangers, Saussure had the additional happiness of living again in a son, whom he saw distinguishing himself in science, and whose beautiful discoveries have merited for him a reputation not less honourable than that of his father; and in a daughter, whose rare virtues and superior mind have rendered her an ornament to her sex.

A Description of some appearances of remarkable Rainbows. By the Reverend WILLIAM SCORESBY, F. R. S. Lond. and Edin. M. W. S., &c. Communicated by the Author. (With a Plate.)*

APPEARANCES of natural phenomena, of rare occurrence, a always worthy of being recorded, both as being intersting to t Read before the Wernerian Natural History Society 10th

observer of nature, and as tending to the development of those beautiful principles with which the Almighty has so universally endued the vast range, and every atom of that vast range of the material creation. And they are further interesting, because, when understood, they generally resolve themselves into the ef fects of some laws, principles, or combinations already known, and afford additional instances of their amazing variety of operations, and of their universality of application. In this view, therefore, even modifications of the more ordinary phenomena, or extreme cases as to beauty, extent, or peculiarity of such, are not undeserving of attention, either to the naturalist or the philosopher.

Hence I am induced to offer to the Wernerian Society an account of two appearances of rainbows-though a phenomenon of such ordinary occurrence; because, in one of these cases, there was exhibited perhaps the extreme of beauty of which this brilliant arch is susceptible; and, in the other case, there was a multiplication of the segments beyond any other example of a rainbow I ever before witnessed.

The first example that I shall mention, so nearly resembled a remarkable rainbow described in a late number of the Edinburgh Philosophical Journal (a rainbow that appeared at Lengsfeldt, on the 18th of May last), that I fear the following description will seem to be little else than a repetition of what is already before the public. At all events, presuming on the interest which observers of nature always feel in such appearances as are at all of an extraordinary character, I shall not withhold the notes which I made on the occasion.

This magnificent phenomenon was seen at Bridlington Quay at 5 P. M. of the 12th of August 1826, during a brilliant sunshine, and a heavy partial shower that passed across from north to south, to the eastward of the town. Both the primary and secondary bows were complete arches, descending to the ground on the left, and to the surface of the sea on the right hand. The colours were of extraordinary brilliancy throughout. Within the arch of the primary bów, were no less than three if not four supernumerary bows in close and regular order, but progressively diminishing in intensity, so that the last was scarcely discernible. The primary bow was of course a series consisting