of them were confiderable, I never failed vifiting thofe lavas whilft they were in full force, and as conftantly examined them and the crater of the volcano after the ceafing of each cruption *. It would be but a repetition of what has been defcribed in my former letters on this fubject, were I to relate my remarks on thofe different expeditions. The lavas, when they either boiled over the crater, or broke out from the conical parts of the volcano, conftantly formed channels as regular as if they had been cut by art down the feep part of the mountain, and, whilft in a state of perfect fufion, continued their courfe in thofe channels, which were fometimes full to the brim, and at other times more or less fo, according to the quantity of matter in motion. Thefe channels, upon examination after an eruption, I have found to be in general from two to five or fix feet wide, and feven or eight feet deep. They were often hid from the fight by a quantity of fcoriæ that had formed a cruft over them, and the lava having been conveyed in a covered way for fome yards, came out fresh again into an open channel. After an eruption I have walked in fome of thofe fubterraneous or covered galleries, which were exceedingly curious, the fides, top, and bottom, being worn perfectly fmooth and even in most parts by the violence of the currents of the red-hot lavas, which they had conveyed for many weeks fucceffively; in others, the lava had incrufted the fides of those channels with fome very extraordinary fcoriæ; beautifully ramified white falts t, in the form of dropping ftalactites, were also attached to many parts of the ceiling of thofe galleries. It is imagined here, that the falts of Vefuvius are chiefly ammoniac, though often tinged with green, deep or pale yellow, by the vapour of various minerals. In the month of May laft, there was a confiderable eruption of Mount Vefuvius, when I paffed a night on the mountain in the company of one of my countrymen, as eager as my felf in the purfuit of this branch of natural history ‡. We faw the operation of the lava, in the channels as above mentioned, in the greatest perfection; but it was, indeed, owing to our perseverance, and fome degree of refolution. After the lava had quitted its regular channels, it fpread itself in the valley, and, being loaded with fcoriæ, ran gently on, like a river that had been frozen, and had maffes of ice floating on it: the wind changing The laft vifit to the crater of Vefuvius, which was in the month of May, 1779, was my fifty-eighth, and to be fure I have been four times as often on parts of the mountain, without climbing to its fummit, and after all am not alhamed to own, that I comprehend very little of the wonders I have feen in this great laboratory of Nature; yet there have been Naturalifts of fuch a wonderful penetrating genius as to have thought themfelves fufficiently qualified to account for every hidden phenomenon of Vefuvius, after having, literally speaking, given the volcano un coup d'œil. I fent a large fpecimen of this curious volcanic production to the British Museum last year. Mr. Bowdler, of Bath. when when we were clofe to this gentle ftream of lava, which might be about fifty or fixty feet in breadth, incommoded us fo much with its heat and smoke, that we muft have returned without having fatisfied our curiofity, had not our guide propofed the expedient of walking across it, which, to our aftonishment, he inftantly put in execution, and with fo little difficulty, that we followed him without hefitation, having felt no other inconveniency than what proceeded from the violence of the heat on our legs and feet; the cruft of the lava was fo tough, befides being loaded with cinders and fcoria, that our weight made not the leaft impreffion on it; and its motion was fo flow, that we were not in any danger of lofing our balance, and falling on it: however, this experiment fhould not be tried, except in cafes of real neceflity; and I mention it with no other view than to point out a poffibility of efcaping, fhould any one hereafter, upon fuch an expedition as ours, have the misfortune to be inclofed between two currents of Java. Having thus got rid of the troublesome heat and fmoke, we coafted the river of lava and its channels up to its very fource, within a quarter of a mile of the crater. The liquid and red-hot matter bubbled up violently, with a hifling and crackling noife, like that which attends the playing off of an artificial firework, and by the continual fplashing up of the vitrified matter, a kind of arch or dome was formed over the crevice from whence the lava iffued. It was cracked in many parts, and appeared red-hot within, like an heated oven: this hollowed hillock might be about fifteen feet high, and the lava that ran from under it was received into a regular channel, raised upon a fort of wall of fcoriæ and cinders, almoft perpendicularly, of about the height of eight or ten feet, refembling much an ancient aqueduct. We then went up to the crater of the volcano, in which we found, as ufual, a little mountain throwing fcoriæ and red-hot matter with loud explosions; but the smoke and fmell of fulphur was fo intolerable, that we were under the neceflity of quitting that curious fpot with the utmoft precipitation. In another of my excurfions to Mount Vefuvius laft year, I picked up fome fragments of large and regular cryftals of clofe-grained lava or bafalt, the diameter of which, when the prifms were complete, may have been eight or nine fuches. As Vefuvius does not exhibit any lavas regularly crystallized, and forming what are vul. garly called giants caufeways (except a lava that ran into the fea near Torre del Greco in 1631, and which in a fmall degree has fuch an appearance), this discovery gave me the greatest pleasure †. After * Bartolomeo, the cyclops of Vesuvius, who has attended me an all my. expeditions to the mountain, and who is an excellent guide. As the fragments of bafalt columns, which I found on the cone of Vefuvius, had been evidently thrown out of its crater, may not lava be more fubject to crystallize within the bowels of a volcano than after its emiffion, and having been expofed to the open air? And may not many of the giants caufeways, already After this flight sketch of the moft remarkable events on Vesuvius fince the year 1767, which I flatter myself will not be unacceptable, as it may ferve to connect what I am going to relate with what ́ has already been communicated to the Society in my former letters on the fame fubject, I come to the account of the late eruption, which affords indeed ample matter for curious fpeculation. As many poetical defcriptions of this eruption will not be wanting, I fhall confine mine to fimple matter of fact in plain profe, and endeavour to convey to you, Sir, as clearly and as diftinctly as I am able, what I faw myself, and the impreffion it made upon me at the time, without aiming in the least at a flowery ftyle. The ufual fymptoms of an approaching eruption, fuch as rumbling noifes and explosions within the bowels of the volcano, a quantity of fmoke iffuing with force from its crater, accompanied at times with an emiffion of red-hot fcoriæ and afhes, were manifeft, more or lefs, during the whole month of July; and toward the end of the month, thofe fymptoms were increased to fuch a degree as to exhibit in the night-time the moft beautiful fireworks that can be imagined. These kinds of throws of redhot fcoriæ and other volcanic matter, which at night are fo bright and luminous, appear in broad day-light like fo many black fpots in the midst of the white smoke; and it is this circumstance that occafions the vulgar and falfe fuppofition that volcanos burn much more violently at night than in the day-time. On Thursday, the 5th of Auguft laft, about two o'clock in the afternoon, I perceived from my villa at Paufilipo, in the bay of Naples, from whence I have a full view of Vesuvius (which is just oppofite, and at the diftance of about fix miles in a direct line from it) that the volcano was in a most violent agitation: a white and fulphureous fmoke iffued continually and impetuously from its crater, one puff impelling another, and by an accumulation of thofe clouds of fmoke refembling bales of the whiteft cotton, fuch a mass of them was foon piled over the top of the volcano as exceeded the height and fize of the mountain itself at leaft four times. In the midst of this very white smoke, an immenfe quantity of ftones, fcoriæ, and afhes, were fhot up to a wonderful height, certainly not lefs than two thoufand feet. I could alfo perceive, by the help of one of Ramfden's most excellent refracting tele copes, at times, a quantity of liquid lava, feemingly very weighty, juft heaved up high enough to clear the rim of the crater, and then take its courfe impetuously down the fteep fide of Vefuvius, oppofite to Somma. Soon after a lava broke out on the fame fide from about the middle of already difcovered, be the nuclei of volcanic mountains, whofe lighter and lefs. folid parts may have been worn away by the hand of time? Mr. Faujeis de St. Fond, in his curious book lately published, and intitled, " Recherches fur les Volcains étaints du Vivarais de Velay," gives (p. 286.) an example of bafalt columns, that are placed deep within the crater of an extinguished volcano. the the conical part of the volcano, and, having run with violence fome hours, ceafed fuddenly, juft before it had arrived at the cultivated parts of the mountain above Portici, near four miles from the fpot where it iffued. During this day's eruption, as I have been credibly informed fince, the heat was intolerable at the towns of Somma and Ottaiano; and was likewife fenfibly felt at Palma and Lauro, which are much farther from Vefuvius than the former. Minute athes, of a reddish hue, fell fo thick at Somma and Ottaiano, that they darkened the air in fuch a manner as that objects could not be diftinguished at the distance of ten feet. Long filaments of a vitrified matter, like fpun glass, were mixed and fell with thefe afhes; and the fulphureous smoke was fo violent, that feveral birds in cages were fuffocated, the leaves of the trees in the neighbourhood of Somma and Ottaiano were covered with white falts very corrofive. About two o'clock in the afternoon, an extraordinary globe of fmoke, of a very great diameter, was diftinctly perceived, by many of the inhabitants of Portici, to iffue from the crater of Veluvius, and proceed haftily towards the mountain of Somma, against which it ftruck and difperfed itself, having left a train of white fmoke, marking the courfe it had taken this train I perceived plainly from my villa, as it lafted fome minutes; but I did not fee the globe itself. A poor labourer, who was making faggots on the mountain of Somma, loft his life at this time; and his body not having been found, it is fuppofed that, fuffocated by the smoke, he must have fallen into the valley from the craggy rocks on which he was at work, and been covered by the current of lava that took its courfe through that valley foon after. An afs, that was waiting for its mafter in the valley, left it very judiciously as foon as the mountain became violent, and, arriving fafe home, gave the firft alarm to this poor man's family. It was generally remarked, that the explosions of the volcano were attended with more noife during this day's eruption than in any of the fucceeding ones, when, moft probably, the mouth of Vesuvius was widened, and the volcanic matter had a freer paffage. It is certain, however, that the great eruption of 1767 (which in every other refpect was mild, when compared to the late violent eruption) occafioned much greater concuffions in the air by its louder explosions. During an eruption of the volcano in the ifle of Bourbon in 1766, fome miles of country, at the distance of fix leagues from that volcano, were covered with a Hexible, capillary, yellow glafs, fome of which were two or three feet long, with fmall vitrous globules at a little distance one from the other. Count Buffon fhewed me fome of this capillary and flexible glafs, which is preserved in the Royal Museum at Paris, and which perfectly refembles the filaments of vitrified matter which fell at Ottaiano, and in other parts on the borders of Vefuvius during this eruption. Sorrentino, in his Iftoria del Vefuvio, publifhed at Naples in 1734, likewife mentions vitrified matter, like herbs and Araw, being found on the ground in the neighbourhood of Vesuvius, during an eruption of that mountain in the year 1724. Friday, Friday, August the 6th, the fermentation in the mountain was lefs violent; but, about noon, there was a loud report, at which time it was fuppofed, that a portion of the little mountain within the crater had fallen in. At night the throws from the crater increafed, and proceeded evidently from two separate mouths, which emitting red-hot fcoriæ, and in different directions, formed a most beautiful and almoft continued firework. On Saturday, Auguft the 7th, the volcano remained much in the fame ftate; but, about twelve o'clock at night, its fermentation increafed greatly. The fecond fever-fit of the mountain may be faid to have manifefted itself at this time. I was watching its motions from the mole of Naples, which has a full view of the volcano, and had been witnefs to feveral glorious picturefque effects produced by the reflection of the deep red fire which iffued from the crater of Vefuvius, and mounted up in the midst of the huge clouds, when a fummer ftorm, called here a tropea, came fuddenly, and blended its heavy watery clouds with the fulphureous and mineral ones, which were al ready like fo many other, mountains, piled over the fummit of the volcano; at this moment a fountain of fire was fhot up to an incredible height, cafting fo bright a light, that the fmalleft objects could be clearly diftinguished at any place within fix miles or more of Veluvius. on The black ftormy clouds paffing fwiftly over, and at times covering the whole, or a part of the bright column of fire, at other times clearing away, and giving a full view of it, with the various tints produced by its reverberated light on the white clouds above, in contraft with the pale flashes of forked lightning that attended the tropea, formed fuch a scene as no power of art can every exprefs. That which followed the next evening was furely much more formidable and alarming; but this. was more beautiful and fublime than even the most lively imagination can paint to itself. This great explofion did not last above eight or ten minutes, after which Vefuvius was totally eclipsed by the dark clouds, and there fell a heavy shower of rain. Some fcoriæ and fmall ftones fell at Ottaiano during this eruption, and fome of a very great fize in the valley between Veluvius and the Hermitage. All the inhabitants of the towns at the foot of the volcano were in the greatest alarm, and preparing to abandon their houses, had the eruption continued longer. One of his Sicilian majesty's game-keepers, who was out in the fields near Ottaiano, whilst this combined ftorm was at its height, was greatly furprised to find the drops of rain fcald his face and hands, which phenomenon was probably occafioned by the clouds having acquired a great degree of heat in paling through the abovementioned column of fire. The King of Naples did me the honour of informing me of this curious circumflance. Sunday, Auguft the 8th, Vefu-' vius was quiet till towards fix o'clock in the evening, when a great fmoke began to gather again over its crater, and about an hour after |