ceed to resume my narrative. I shall first speak briefly of a phenomenon relative to the smoke which arises from the crater of Etna, and which was seen differently by Mr. Brydone, Count Borch, and myself. Mr. Brydone tells us that, " from many places of the crater issue volumes of sulphureous smoke, which being much heavier than the circumambient air, instead of rising in it, as smoke generally does, immediately on its getting out of the crater, rolis down the side of the mountain, like a torrent, till coming to that part of the atmosphere of the same specific gravity with itself, it shoots off horizontally, and forms a large track in the air according to the direction of the wind."

On the contrary, the smoke when seen by Count Borch, at the intervals when the air was calm, arose perpendicularly to a great height, and afterwards fell, like white fleeces, on the top of the mountain. I shall not presume to doubt these two facts, though I observed neither of them. The two columns of smoke which I saw, though bent somewhat from the perpendicular by the wind, ascended with the usual promptitude of ordinary smoke (a certain proof that it was considerably lighter than the ambient air), and, when at a great height, became extremely rarefied and dispersed. This difference in the appearance of the smoke, as observed by the two authors before mentioned and myself, may arise not only from the gravity of the air on Etna being different at different times, but also from the diversity of the smoke, which may be sometimes lighter and sometimes heavier than the air that surrounds it; differing in its nature according to the quality of the substances from which it is produced. Such a variation in its specific gravity must induce us to conclude that the bodies which burn within the crater are specifically different.

The effects of the air at the summit of Etna, as experienced by myself and some of the travellers I have before cited, were likewise different. Sir William Hamilton tells us, that the thinness of that fluid occasioned a difficulty of respiration; and Count Borch appears to have experienced a still greater inconvenience of that kind, since he says "The rarity of the air on this mountain is extremely sensible, and almost renders that fluid unfit for respiration." On the contrary, Baron Riedesel felt no such effect, as far at least as we can judge from his own words. "I did not perceive, as several travellers have asserted, that the air here is so thin and rarefied as to

prevent, or or at least greatly incommode, respiration." Mr. Brydone has said nothing on the subject, and his silence may induce us to conclude that he experienced no difficulty.

I, my servant, and two guides, suffered no inconvenience from the air. The exertions we had made, indeed, in climbing up the craggy steep declivities which surround the crater, had produced a shortness of breathing; but when we had reached the summit, and recovered from our weariness by rest, we felt no kind of inconvenience, either while sitting, or when, incited by curiosity, we went round and examined different parts of the edges of the crater. The same is affirmed by Borelli: " Æquè bene respiratio in cacumine Ætnæ absolvitur, ac in locis subjectis campestribus."-"Respiration is performed with the same ease on the top of Etna, as in the country below."

Several writers have treated of the difficulty of respiration experienced by those who travel over high mountains, and other incon. veniencies to which they are exposed; but none, in my opinion, more judiciously than M. Saussure, in his Travels among the Alps. The observations he has made appear to me to explain the cause of these different accounts relative to the effect of the air on the top of Etua. When the height above the level of the sea was 2450 poles, or nearly such, which he found to be that of Mount Blanc, every individual felt more or less inconvenience from the rarefaction of the air, as happened to himself and nineteen persons who accompanied him, when, in August 1787, he ascended that mountain. But when the elevation was much less, as for example 1900 poles, some of these persons felt no difficulty, among whom was this naturalist; though he confesses that he began to experience inconve. nience as he ascended higher. We have not indeed any certain observations relative to the exact height of Etna, as is sufficiently proved by the different estimates given by different naturalists. Signor Dangois, however, astronomer at Malta, in the year 1787, measured the height of this mountain by a geometrical method, and the public anxiously expects the results, which will satisfactorily solve this important problem. In the mean time, from comparing the measures hitherto assigned, the elevation of Etna above the level of the sea is probably somewhat less than 1900 poles. Hence we understand why respiration in many persons is not incommoded, while the contrary happens to others, according to the different strength and habit of body of different individuals.

After having for two hours indulged my eyes with a view of the interior of the crater, that is, in the contemplation of a spectacle which, in its kind, and in the present age, is without a parallel in the world; I turned them to another scene, which is likewise unequalled for the multiplicity, the beauty and the variety of objects it presents. In fact, there is perhaps no elevated region on the whole globe which offers, at one view, so ample an extent of sea and land as the summit of Etna. The first of the sublime objects which it presents is the immense mass of its own colossal body. When in the country below it, near Catania, we raise our eyes to this sovereign of the mountains, we certainly survey it with admiration, as it rises majestically, and lifts its lofty head above the clouds; and with a kind of geometric glance we estimate its height from the base to the summit; but we only see it in profile. Very different is the appearance it presents, viewed from its towering top, when the whole of its enormous bulk is subjected to the eye. The first part, and that nearest the observer, is the Upper Region, which, from the quantity of snows and ice beneath which it is buried during the greater part of the year, may be called the frigid zone, but which, at that time, was divested of this covering, and only exhibited rough aud craggy cliffs, here piled on each other, and there separate and rising perpendicularly; fearful to view and impossible to ascend. Towards the middle of this zone, an assemblage of fugitive clouds, irradiated by the sun, and all in motion, increased the wild variety of the scene. Lower down, appeared the Middle Region, which from the mildness of its climate, may merit the name of the temperate zone. Its numerous woods, interrupted in various places, seem, like a torn garment, to discover the nudity of the mountain. Here arise a multitude of other mountains, which in any other situation would appear of gigantic size, but are but pigmies compared to Etua. These have all originated from fiery eruptions. Lastly, the eye contemplates, with admiration, the Lower Region, which, from its violent heat, may claim the appellation of the torrid zone; the most extensive of the three, adorned with elegant villas and castles, verdant hills, and flowery fields, and terminated by the extensive coast, where, to the south, stands the beautiful city of Catania, to which the waves of the neighbouring sea serve as a mirror.

But not only do we discover, from this astonishing elevation, the

entire massy body of Mount Etna; but the whole of the island of Sicily, with all its noble cities, lofty hills, extensive plains, and meandering rivers. In the indistinct distance we perceive Malta; but have a clear view of the environs of Messina, and the greater part of Calabria; while Lipari, the fuming Vulcano, the blazing Stromboli, and the other Eolian isles, appear immediately under our feet, and seem as if, on stooping down, we might touch them with the finger.

Another object no less superb and majestic, was the far-stretching surface of the subjacent sea which surrounded me, and led my eye to an immense distance, till it seemed gradually to mingle with the heavens.

Seated in the midst of this theatre of the wonders of nature, I felt an indescribable pleasure from the multiplicity and beauty of the objects I surveyed, and a kind of internal satisfaction and exultation of heart. The sun was advancing to the meridian, unobscured by the smallest cloud, and Reaumur's thermometer stood in the tenth degree from the freezing point. I was therefore in that temperature which is most friendly to man; and the refined air I breathed, as if it had been entirely vital, communicated a vigour and agility to my limbs, and an activity and life to my ideas, which appeared to be of a celestial nature.

[Spalanzani's Travels.]

CHAP. XI.

VOLCANOES OF THE LIPARI ISLANDS.

To the northward of Sicily lies a cluster of small islands, almost all of which contain volcanoes, that of Stromboli being the chief. The crater of this last is peculiarly characterised by its frequent momentary eruptions of stones, which, in consequence of its being confined on the side of a bill, are thrown back by a recoil, and relapsing into the volcano supply it afresh with endless materials. The island of this group, which is named Vulcano, has a larger crater, but its

materials seem exhausted, The isle of Lipari, containing the town of the same name, presents vast rocks of volcanic glass; and it is from the hill called Campo Bianco, three miles from the town of Lipari, that Europe is chiefly supplied with pumice-stones for different purposes. Felicuda and Alicuda, the two extreme Liparian islands towards the west, display equal proofs of their having formerly contained volcanoes; and modern authors have discovered similar traces in the isle of Ischia, and in those of Penza to the north of the gulph of Naples; while that of Capri, to the south of the Neapolitan gulph, is supposed to be chiefly calcareous.

The best account we have received of the volcanic phenomenon of Stromboli is that of Spalanzani, from whom we shall take leave. to present our readers with the few following detached extracts.

I SHALL now proceed to relate what I observed relative to the vol. cano on the night of the 1st of October. My residence was in a cottage, on the north side of the island, about half a mile from the sea, and two miles from the volcano; but so situated that the cloud of smoke round the mountain scarcely permitted me to see the top of the fiery ejections. I employed more hours of the night in making my observations, than I permitted myself for repose; and the following is a brief summary of the principal appearances I noticed.

The south-east wind blew strong. The sky, which was clear, the moon not shining, exhibited the appearance of a beautiful aurora borealis over that part of the mountain where the volcano is situated, and which, from time to time, became more red and brilliant, when the ignited stones were thrown to a greater height from the top of the mountain. The fiery showers were then more copious, and the explosions which followed them louder, the strongest resembling those of a large mine which does not succeed properly, from some cleft or vent. Every explosion, however, slightly shook the house in which I was, and the degree of the shock was proportionate to the loudness of the sound. I do not believe that these shocks were of the nature of the earthquake; they were certainly to be ascribed to the sudden action of the fiery ejections on the air, which struck the small house in which I was, in the same manuer as the discharge of a cannon will shake the windows of the neighbouring houses, and sometimes the houses themselves. A proof of this is, that the