1780.

1787.

Several new craters were formed in the year 1780; one of them about two miles below the opening of 1766; and from February to May, continual convulsions occurred, and quantities of pumice stones and sand were discharged. The most considerable crater was formed, on the 23d of the last mentioned month, on Mount Fumento, on the summit of Etna: á stream of lava was ejected on this occasion which spread at the rate of a mile in a day through the valley of Laudunza. The lava issuing from two other openings diffused itself to the distance of seven miles in six days. From another crater, produced on the 25th, red hot stones were projected to a great distance, and a stream of fire ran over a tract of country two miles in extent, in a very short space of time.

Gioeni has given an accurate account of another eruption, which happened in the month of July, 1787, which was preceded for sixteen or seventeen days by the ordinary indications. On the seventeenth, after several slight shocks of earthquake, lava began to flow from the back part of one of the two hills which form the double head of Etna. On the following day after some hours of tranquillity, the subterraneous commotions encreased, the smoke thickened, till at length there fell a shower of fine brilliant black sand; on the eastern side, a quantity of stones were thrown out, and flashes of fire accompanied with a flood of scoriæ and lava were observed at the foot of the mountain. About sun-set conical flames issued from the volcano in different directions, alternately rising and falling; and at three o'clock in the morning, the mountain had the appearance of being cleft, while the upper part seemed one burning mass. Two of the flames were of vast extent, and the intermediate space was occupied by another, composed of several minor flames, ascending from a base of a mile and a half in diameter, to. the height of two miles. A phænomenon hitherto unobserved in former conflagrations was here exhibited. The cone was covered with a very thick smoke, which was pervaded with brilliant flashes of lightning, and sounds were frequently heard resembling the explosion of large cannon. A jet of flaming volcanic substances was thrown from the cone, as from a fountain, to the distance of six or seven miles, and so thick a smoke issued from the base of the cone, as to obscure considerable portions of the flame when the lava was discharged. This beautiful scene lasted three quarters of an hour; it began again, and with greater force, the next night, but was then of much shorter duration: flames, smoke, and ignited stones in showers, were projected during the intervals. After the eruption, the summit of the mountain, on the western side, was overspread with hardened lava, scoriæ, stones, and smoke; mephitic vapours, showers of sand, and intense heat continued their annoying operations. The lava on the west separated into two branches; the one of which proceeded towards Libeccio, the other, in the

direction of the Bronte and the plain of Lago. It had AETNA. evidently been in a state of fusion; and the odour of the liver of sulphur was emitted from one of the spiracula. The breadth of the lava was from nearly fourteen to twenty-one feet, its depth thirteen feet and three quarters, and its extent two miles.

In October of the same year, another eruption occurred, which has been described by Spallanzani. The stream of lava, on this occasion, from the great crater, was three miles long, with differing breadth, in some places a quarter of a mile, in others, one third, or even more; varying also in depth from six to eighteen feet. Its course was westerly, and its effervescence violent. The most recent eruption took place in the month Last of March, 1809. A very animated, interesting, and eruption. minute account was transmitted at the time, in a letter from a British officer in Sicily, to his friends in Scotland; which our readers no doubt will deem worthy of insertion. It is dated Messina, April 24, 1809, and proceeds thus:

"On the morning of the 27th of March (1809), about 7 o'clock, advices of an eruption of Ætna, were conveyed hither (Messina) by a very swift courser, a cloud of black ashes from the mountain top, which is fifty miles distant, in a strait line. These ashes borne on a hard gale of wind, showered into the town in such quantities, that several cart loads might have been collected from the streets and house-tops. They resembled gunpowder; so much so indeed, that an Irish soldier in the citadel called out, "blood and turf! the wind has forced open the magazine doors, and there's all the powder blowing about the barracks!"

"Soon after daylight, an awful bellowing and horizontal shaking of the mountain excited a general alarm among the inhabitants of its vast regions. Uncertain where the calamity might fall, many deserted their houses. This shock was immediately succeeded by a furious eruption of ashes from the great crater, which formed immense clouds, and covered an amazing extent of country. So violent was the discharge, that, in spite of the gale, a vast quantity overspread the country, many miles to windward of the spot whence they issued.

"On the evening of the same day, an eruption of lava took place at a short distance below, whose terrible stream flowed down the mountains about three miles, and then divided into two branches. This volcano soon ceased burning, and another broke out next day, with greater fury than the former, about five miles lower down, at a place called Monte Negro. This one displayed three vast columns of flame and smoke, and its lava extended, in a few days, across the woody region, to the distance of three or four leagues. Hitherto we have heard of no guide bold enough to conduct the curious traveller as far as either of these eruptions, because of the vast and deceitful heaps of snow and ashes scattered about the two upper regions of the mountain; nor has any person, I believe, been yet so rash as to ascend higher than one which broke out two hours after the first alarm, about twelve miles below Monte Negro, and eight west of Lingua Grossa, a town on the north east side, near the foot of Etna. This eruption has formed a row of craters, within a space of about two miles, forming with the others, an irregular line, running in a north east direction from the top of the mountain.

"From the dark bosom of a wood of tall firs and huge

ATNA. oaks, spread over steep craggy hills and close valleys, conceive twelve craters or mouths, two unceasingly, and the rest at intervals, with a noise like a tremendous chorus of several thousand cannons, muskets, and sky rockets, discharging flame, and showers of burning rocks of various forms and all magnitudes, from several yards in diameter down to the smallest pebble, which, according to their weight and bulk, ascend from 200 to 1000 feet. The two fore-mentioned craters (or rather double crater), the lowest of the row down the mountain, formed the principal object of this awful and magnificent scene-they were the only craters which did not seem to labour. Their joint emissions had encompassed them with a black oblong hill of ashes and lava stones; 30 yards above the top of which their mingling flames furiously ascended, in one immense blaze, which seemed 100 yards in breadth. Amidst this blaze, vast showers of rocks, rising and falling, were continually passing each other. About the middle of the whole line of craters was situated one, which laboured the most, and made the loudest, the heaviest, the highest, and the most dangerous discharges; from the rocks of which our party twice narrowly escaped one or two of very considerable size, falling within a pace of us :-I think the lava flowed only from a few of the chief craters, particularly the double one. During the emissions of rock and flame, the boiling matter was seen in slow undulating waves issuing through the sides, close to the bottom of the black hills of ashes. The double crater appeared completely isolated by the lava of the others. Just below it, all the lavas uniting, formed one grand stream of various breadths, from half a mile to 50 yards, which, leaving the fir wood, pursued its destructive course down a rocky part of the mountain, interspersed with oaks; until, about five miles below the double crater, it entered some vineyards, after dividing into two branches, the principal one of which advancing a mile farther directly threatened the house of baron Carri. Within 200 ya.ds of this house, it entered a hollow way, which it was hoped would turn its course; but, going on, according to the direction of the impelling fluid behind, its loose rocks rolling off the main body soon filled up the small ravine, and formed a causeway for itself to pass. The other branch took the direction of Lingua Grossa, and arrived very near the baron Cagnone's house, whose inhabitants, as well as those of the town, were trembling for their property, when the eruption ceased.

"The stream sometimes branched off and joined again, forming islands as it flowed along. Sometimes its banks were formed by the sides of ravines; but where the country was open it formed its own, which from the porous nature of the lava, imbibed the cool air and soon hardened into black and lofty banks of many feet in thickness. It gradually thickened in advancing, until about four miles from the crater, when it began to assume the appearance of a vast rugged mound of black rocks, or stones and cinders, moving almost imperceptibly along. By daylight, the general appearance of this amazing stream, or moving mound, was black, and might be compared to a long tract of ploughed ground, moving and smoking along, raised on banks from fifteen to forty feet high. The end of it, however, presented a bold front of vivid fire, about fifteen or sixteen feet high, and eighty paces in extent. While it moved forward in a body, the loose stones and cinders, present

ing less resistance to the stream behind, impelled in a ETNA continual succession from the top, rolled cracking down its rough sloping sides and front, advancing before the main body, and burning the grass, the weeds, and grape vines, like light troops skirmishing on the front and flanks of an army marching in solid column.

"I never saw a painting which gave any thing like a correct idea of lava, yet it appears no difficult task. I could discern nothing of the fluid part of the stream; yet, until somewhat cooled, by flowing several miles, it must be liquid immediately underneath the thin light crusted surface. Just after issuing from the crater, I should think it flowed at the rate of four miles an hour; half way down the stream (whose whole extent, when the eruption ceased, was about six miles), a mile and a-half an hour, and so on, gradually decreasing in velocity to the most advanced part, where its progress was a few hundred yards a day.

"The night view of the eruption and stream of lava was truly grand and terrific. The rocks emitted from the craters displayed a white heat, and the flames an intense red. When the adjacent hills and valleys were covered by a shower of rocks, they appeared, for a time, beautifully spangled with stars, whose silver brightness, as well as that of the burning trees, formed a no less admirable contrast to the flames of the crater than did the evening songs of the birds to the bellowing of the mountain. The lava was a fancied infernal fire, streaked black and red, presenting a horrid contrast to the dark surrounding scenery. Here, down the rocky slopes, it rolled a cataract of fire; there, it displayed floating mounts crowned with imagined fortresses. Trees were seen, as if growing from the fire, whose parched branches and burning trunks exhibited the idea of desolation in all its horrors.

"The country about Lingua Grossa, Pie Monte, and other places on that side of the mountain, now lies covered with ashes, three or four inches in depth. Though some lands have suffered by lava, many have been manured by ashes, and the whole island is freed from the dread of earthquakes for some time to come. Thus we find

"All partial evil universal good."

Except the inhabitants likely to suffer, little concern or curiosity was expressed by the Sicilians. Even the baron Carri, whose house was so much in danger, with superstitious obstinacy rejected, for a long while, every proposal of the British officers for removing his property. "No, no," he always replied, "Let it be as God wills it." At length, however, self-interest prevailed, and solitary walls alone remained. But when the lava had arrived within 200 yards of this deserted habitation the eruption ceased, to the great joy of the natives, who attributed this mercy to the merits and interference of their patron saints, whose images were daily brought from Castiglione (a distance of three miles) in procession, during the progress of this calamity, and placed, while mass was performed, amidst the tears of a wretched multitude, a few yards in front of the slow advancing fire. This procession was composed of the miserable and ragged natives, of both sexes and all ages, crying and sobbing, beating their breasts, tearing their hair, and flogging their backs in penance, while their priests were calling on all their saints to assist them. On their way to the lava, they stopped at the baron's house, from the balcony of which,

NA the chief priest, with the most violent gestures of grief, delivered a short sermon, in which he told them the eruption was a judgment upon their sins, and recommended them to mend their lives, and pray to all the saints to intercede for them. Every pause of this discourse was filled with a general burst of tears, beating of breasts, tearing of hair, and flogging of backs. I was never more affected by any scene of public distress. "What mortal can dare to think he breathes a single moment without divine assistance? How feeble, how insignificant does he feel who stands within 200 yards of these furious volcanoes. What must be the pangs of his heart, who beholds his earthly property, his native fields, in a few hours irrecoverably overwhelmed. Transitory, compared with this, are all the other Scourges of the earth. The fertility swept away by floods and tempests, by war and pestilence, is shortly succeeded by smiling plenty. The fields of Austerlitz and Jena already revive from their late desolation. Even Spain may, perhaps, smile ere long; but many successive generations, with hopeless sighs, must view the black and barren rocks which have buried the native lands of their unhappy forefathers."

es of

The causes of the volcanic fire, whose effects are so olcanic tremendous, have often occupied the attention of philosophers, the variety of whose opinions render it extremely desirable that this subject should be still more minutely and laboriously investigated. Some attribute volcanoes entirely to the action of electricity; but while this agent may be admitted to possess a wonderful power, to pervade with extensive diffusion the realms of nature, and evidently to produce some of the appearances which accompany volcanic eruptions, it does not furnish a sufficient solution of the great problem respecting the origin and operations of these phænomena. Some have applied to this curious inquiry the experiment of the fermentation of sulphur and iron, which, when mixed in large quantities, and moistened with water, will take fire; hence pyrites, which consist of this mixture, may occasion the explosions in question. It has been observed, almost all the volcanoes of which we have any knowledge, are found in the immediate vicinity of the sea, which fact throws an air of considerable probability over this theory; for the water finding access to the central base of the mountain, occasioning a fermentation with the beds of pyrites already existing there, might produce the volcanic eruption. Still it is difficult to conceive how masses of pyrites can remain for many centuries under the surface, being frequently inflamed, and then returning to a quiescent state, till re-acted upon and reinflamed, and thus perpetually renewed for the same kind of operation. We cannot imagine a sufficient quantity in such a situation, nor such a result without the access of air. Others, however, imagine that it results from a central fire, to which Etna, Vesuvius, and other mountains, are so many vents or chimnies. Dr. Woodward, and Dr. Hutton in particular, advocate this opinion; but it has been justly objected, that this theory would involve inexplicable difficulties: it would suppose the existence of a fire, which if sufficient to produce the effect, must soon dissolve the globe itself; since, if all the burning mountains upon its surface were incessantly pouring forth rivers of lava, they would be wholly inadequate to give vent to so immense a furnace: besides, that the supposition would

require constant and simultaneous eruptions, which ÆTNA. does not accord with fact.

M. Houel, in his Voyage Picturesque, proposes Houel's a theory of the volcanic fire, which at least merits a theory. particular detail. He observes, that we can form no idea of fire subsisting alone, without any pabulum, and unconnected with any other principle. It is only seen in conjunction with some other body which nourishes it. The matter in fusion, which issues from the focus, is but the incombustible part of that which nourishes the fire, into the bosom of which it penetrates in search of pabulum. But the bottom of the volcano is the only part on which it acts, because the fire can only operate in proportion to the facility with which it can dissolve and evaporate; and its action extends no further than to keep the substances it has melted in a state of ebullition. The fusible matter which is ejected from the mouth of the volcano, hardens by degrees as it cools in the external air, and produces that species of stone which is commonly denominated lava. Even in a Lava. state of fluidity, and when in the burning focus, lava, on account of its gravity and density, must possess some considerable degree of solidity; in consequence of which it resists and irritates the fire into a state of ebullition. A quantity of matter, in such circumstances, must resemble generally any other thick substance or concreted mass in a boiling state, and small explosions are liable to be produced, from time to time, upon every part of the surface of this heated matter, by which means small particles or pieces are scattered around in every direction. A similar process is carried on, though on a much larger scale, in the focus of a volcano, and the explosions there, though precisely of the same nature, produce proportionably greater effects, repelling with the utmost violence whatever lies in the way or offers any resistance. When it is considered how much the volcanic focus is sunk below the base of the mountain, that the mountain itself is ten thousand feet high, and that the power exerted must be sufficient to raise these masses twelve thousand feet perpendicular, the boldest imagination is confounded. What a force must it require to raise such a rock as that of sixteen tons weight on the top of Etna, and which must have described a parabola of a league in diameter, after its projection from the mouth of the crater!

tions.

One of the most accurate of scientific travellers in Humboldt's modern times (M. Humboldt) remarks, that the observamineralogists who think that the end of the geology of volcanoes is the classification of lavas, the examination of the crystals they contain, and their description, according to their external characters, are generally very well satisfied, when they come back from the mouth of a burning volcano. They return loaded with numerous collections, which are the principal objects of their researches. This is not the feeling of those, who, without confounding descriptive mineralogy with geognosy, enendeavour to raise themselves to ideas generally interesting, and seek, in the study of nature, for answers to the following questions:

Is the conical mountain of a volcano entirely formed of liquified matter, heaped together by successive eruptions; or does it contain in its centre a nucleus of primitive rocks covered with lavas, which are these same rocks altered by fire? What are the affinities

• Oryctognosy.

ETNA. which unite the productions of modern volcanoes with the basaltes, the phonolites, and those porphyries with basis of felspar, which are without quartz, and which cover the Cordilleras of Peru and Mexico, as well as the small groups of the Monts d'Or, of Contol, and of Mézen in France? Has the central nucleus of volcanoes been heated in its primitive position, and raised up, in a softened state, by the force of the elastic vapours, before these fluids communicated, by means of a crater, with the external air? What is the substance, which, for thousands of years, keeps up this combustion, which is sometimes so slow, and at other times so active? Does this unknown cause act at an immense depth, or does this chemical action take place in secondary rocks lying on granite?

"The further we are from finding a solution of these problems in the numerous works hitherto published on Ætna and Vesuvius, the greater is the desire of the traveller to see with his own eyes. He hopes to be more fortunate than those who have preceded him; he wishes to form a precise idea of the geological relations the volcano and the neighbouring mountains bear to each other; but, how often is he disappointed, when, on the limits of the primitive soil, enormous banks of tufa and puzzolana render every observation on the position and stratification impossible! We reach the inside of the crater with less difficulty than we at first expected, we examine the cone from its summit to its basis; we are struck with the difference in the produce of each eruption, and with the analogy which still exists between the lavas of the same volcanoes; but notwithstanding the care with which we interrogate nature, and the number of partial observations which are presented at every step, we return from the summit of a burning volcano less satisfied, than when we were preparing to go thither. It is after we have studied them on the spot, that the volcanic phenomena appear still more isolated, more variable, more obscure, than we figure them when consulting the narratives of travellers." Personal Narrative, vol. i. p. 197, &c. Tr.

The same eminent writer has made several interesting observations with regard to the connection of volcanoes with earthquakes. Though this subject will require a fuller elucidation under some other articles of a more general nature, we take the liberty of inserting another extract in this place from the Personal Narrative.

"In New Andalusia, as well as in Chili and Peru, the shocks (of earthquakes) follow the course of the shore, and extend but little inland. This circumstance, as we shall soon find, indicates an intimate connection between the causes that produce earthquakes and volcanic eruptions. If the earth was most agitated on the coasts, because they are the lowest part of the land, why should not the oscillations be equally strong and frequent on those vast savannahs or meadows, which are scarcely eight or ten toises above the level of the ocean?

"The earthquakes of Cumana are connected with those of the West India islands, and it has even been suspected that they have some connection with the volcanic phenomena of the Cordilleras of the Andes. On the 4th of November, 1797, the soil of the province of Quito underwent such a destructive commotion, that, notwithstanding the extreme feebleness of the population of that country, near 40,000 natives perished buried under the ruins of their houses, swal

lowed up in the crevices, or drowned in lakes that ATNA were suddenly formed. At the same period, the inhabitants of the eastern Antilles were alarmed by shocks, which continued during eight months, when the volcano of Guadaloupe threw out pumice-stones, ashes, and gusts of sulphureous vapours.

"This eruption of the 27th of September, during which very long continued subterraneous noises were heard, was followed on the 14th of December, by the great earthquake of Cumana. Another volcano of the West India islands, that of St. Vincent's, has lately given a fresh instance of these extraordinary connections. This volcano had not emitted flames since 1718, when they burst forth anew in 1812. The total ruin of the city of Caracas, preceded this explosion, thirty-five days; and violent oscillations of the ground were felt, both in the islands, and on the coasts of Terra Firma.

"It has long been remarked, that the effects of great earthquakes extend much farther than the phænomena arising from burning volcanoes. In studying the physical revolutions of Italy, carefully examining the series of the eruptions of Vesuvius and Etna, we can scarcely recognise, notwithstanding the proximity of these mountains, any traces of a simultaneous action. It is, on the contrary, doubtless, that at the period of the last and preceding destruction of Lisbon, the sea was violently agitated even as far as the New World; for instance, at the island of Barbadoes, more than twelve hundred leagues distant from the coasts of Portugal.

"Several facts tend to prove, that the causes which produce earthquakes have a near connection with those that act in volcanic eruptions. We learnt at Pasto, that the column of black and thick smoke, which in 1797, issued for several months from the volcano near this shore, disappeared at the very hour, when, sixty leagues to the south, the towns of Riobamba, Hambato, and Tacunga, were overturned by an enormous shock. When, in the interior of a burning crater, we are seated near those hillocks formed by ejections of scoria and ashes, we feel the motion of the ground several seconds before each partial eruption takes place. We observed this phænomenon, at Vesuvius in 1805, while the mountain threw out scoriæ at a white heat; we were witnesses of it in 1802, on the brink of the immense crater of Pichincha, from which nevertheless at that time clouds of sulphureous acid vapours only issued." Personal Nar. vol. ii.

As involving some questions of considerable im- Formati portance, we have deferred to the closing part of this of Etm article, the subject of the formation and structure of Etna. Like every thing else belonging to the history of this remarkable production of nature, it has given birth to many and diversified speculations, into which the most legitimate curiosity will be naturally eager to enter. The magnitude of this mountain has induced M. Buffon to consider it as one of the primitive order, which subsisted both as a mountain and a volcano, at the creation of the world. He believes that its eruptions ceased for a long period after the waters subsided from the surface of the earth, on account of a deficiency of fluid to occasion an effervescence with the minerals it contained. According to this writer, the volcanic eruptions of the mountain were not renewed till the bursting open of the Straits of Gibraltar, and the Bos