of fire, which falling ftill in fome degree of fufion, has, in a manner, cafed up the conical part of Vefuvius with a ftratum of hard fcoriæ: on the fide next the mountain of Somma, that ftratum is furely more than one hundred feet thick, forming a high ridge. The valley between Vefuvius and Somma has received fuch a prodigious quantity of lava and other volcanic matter during this laft eruption, that it is raifed, as is imagined, two hundred and fifty feet or more. Three fuch eruptions as the last would completely fill up the valley, and, by uniting Vefuvius and Somma, form them into one mountain, as they moft probably were before the great eruption in the reign of Titus. In fhort, I found the whole face of Vefuvius changed. Thofe curious channels, in which the lava ran in the month of May laft, are all buried. The volcano appears to have likewife encreased in height; the form of the crater is changed, a great piece of its rim towards Somma being wanting; and on the fide towards the fea it is alfo broken. There are fome very large cracks towards the point of the cone of the volcano, which makes it probable, that more of the borders of the crater will fall in. The ridge of fresh volcanic matter on the cone of Vesuvius towards Somma, and the thick ftratum in the valley, are likewife full of cracks, from which there iffues a conftant fulphureous fmoke that tinges them and the circumjacent fcoriæ and cinders with a deep yellow, or * Sorrentino mentions, in his Iftoria del Vefuvio, that the volcano in 1676 vented itself in the like manner : "Non a torrenti modo mando fuori le fue viscere, ma tutti in aria menolla." Such wonderful, violent, and fudden emiffions of liquid lava muft have been occafioned by fome accidental and extraor dinary cause; and I was inclined to think, that a fudden communication of water with the lava in fufion might be the occafion of fuch a phænomenon, particularly as we know that pools of rain-water have been found formerly in caverns within the bowels of Vefuvius; and that a river, supposed to be that anciently called Draco, and which was buried by an ancient eruption, burst out fome years ago with fuch force, from under a ftratum of lava at Torre del Greco, as to be fufficient to turn mills there; but a late curious experiment, mentioned by Monf. de Faujas, in his Recherches fur les Volcans éteints, p. 176, feems to contradict my fuppofition; and that water introduced to the furnace of a volcano, finding there a more rarefied air, would not produce an explosion. Monf. Deflaudes, Director of the Royal Manufacture of Looking-glafs at St. Gobin, made the following experiment in 1768, in the prefence of the Duke de la Rochfoucault, Monf. de Faujas, and others. He poured fome water upon a quantity of glafs in fufion, and which had been in that ftate in the crucible for twelve hours. The water did not occafion the leaft fermentation; but, on the contrary, rolled upon its furface, without even producing any fimoke; and after having become feemingly red-hot, like the metal in fufion, difappeared in about three minutes, without having occafioned the leaft explosion. If the great emiffions of lava above-mentioned were not then occafioned by water mixing with the lava, may not they have been produced by violent fubterraneous exhalations having forced their way into the cauldron of the volcano (if I may be allowed the expreffion) replete with matter in fufion, and blown its whole contents, with whatever oppofed its paffage, at once into the air? fometimes a white tint. Thefe lastmentioned cracks, though deep, do not, as I apprehend, pafs the ftratum formed by the latt eruption, and which, from its extreme thickness, particularly in the valley, will probably retain a great degree of heat for fome years to come, as did a thick ftratum of lava that ran into the foffe grande in the year 1767. The number and fize of the ftones, or, more properly fpeak ing, of the fragments of lava which have been thrown out of the volcano in the courfe of the laft eruption, and which lie fcattered thick on the cone of Vesuvius, and at the foot of it, is really incredible. The largest we measured was in circumference no less than one hundred and eight English feet, and seventeen feet high. It is a folid block, and is much vitrified: in fome parts of it there are large pieces of pure glafs, of a brown yellow colour, like that of which our common bottles are made, and throughout its pores feem to be filled with perfect vitrifications of the fame fort. The fpot where it alighted is plainly marked by a deep impreffion almoft at the foot of the cone of the volcano, and it took three bounds before it fettled, as is plainly perceived by the marks it has left on the ground, and by the ftones which it has pounded to atoms under its prodigious weight. When we confider the enormous fize and weight of fuch a folid mafs, thrown at least a quarter of a mile clear of the mouth of the volcano, we can but admire the wonderful powers of nature, of which, being fo very feldom within the reach of humaninfpection, we are in general too apt to judge upon much too small a fcale. Another folid block of ancient lava, fixty-fix feet in circumference, and nineteen feet high, being nearly of a fpherical shape, was thrown out at the fame time, and lies near the former. This ftone, which has the marks of having been rounded, nay, almoft polished, by continual rolling in torrents, or on the fea-fhore, and which yet has been fo undoubtedly thrown out of the volcano, may be the fubject of curious fpeculations *. Another block of folid lava that was thrown much farther, and lies in the valley between the cone of Vefuvius and the Hermitage, is fixteen feet high, and ninety-two feet in circumference, though it plainly appears, by the large fragments that lie round, and were detached from it by the fhock of its fall, that it must have been twice as confiderable when in the air. There are thousands of very large fragments of different fpecies of ancient and modern lavas, that lie fcattered by the late explofions on the cone of Vefuvius, and in the vallies at its foot; but these three were the largest of those we measured †. We Or may not this ftone be a fpherical volcanic bafalt, fuch as one of fortyfive feet in circumference, defcribed by Monf. Faujas de St. Fond, in p. 155 of his curious book on the subject of extinguished volcanos?, We measured two other ftones in the valley between Somma and Vefuvius; the one was twenty-two feet and a half long, thirteen feet and a half broad, and ten We found alfo many fragments of thofe volcanic bombs that burst in the air, as mentioned in the former part of this journal; and fome entire, having fallen to the ground without burfting. The fresh red-hot and liquid lava having been thrown up with number lefs fragments of ancient lavas, the latter were often clofely enveloped by the former; and probably when fuch fragments of lava were porous and full of air bubbles, as is often the cafe, the extreme outward heat fuddenly rarefying the confined air, caufed an explofion. When these fragments were of a more compact lava they did not explode, but were fimply enclofed by the fresh lava, and acquired a fpherical form by whirling in the air, or rolling down the fleep fides of the volcano. The fhell or outward coat of the bombs that burft, and of which we found feveral pieces, was always compofed of fresh lava, in which many fplinters of the more ancient lava that had been enclosed are feen sticking. I was much pleafed with this difcovery, having been greatly puzzled for an explanation of this volcanic operation, which was new to me, and which was very frequent during the eruption of the 9th of Auguft. The phænomenon of the natural Spun-glafs which fell at Ottaiano with the afhes on the 5th of Auguft, was likewife clearly explained to me here. I have already mentioned, that the lava thrown up by this eruption was in general more perfectly vitrified than that of any former eruption, which appeared plainly upon a nearer ex ten feet high; the other eleven feet and circumference, amination of the fragments of fresh lava, the pores of which we generally found full of a pure vitrification, and the fcoriæ themselves, upon a clofe examination with a magnifying glafs, appeared like a confufed heap of filaments, of a foul vitrification. When a piece of the folid fresh lava had been cracked in its fall without feparating entirely, we always faw capil-, lary fibres of perfect glafs, reaching from fide to fide within the cracks. If I may be allowed a mean comparifon, which, however, conveys the idea of what I wish to explain better than any other I can think of, this lava refembled a rich Parmesan cheese, which, when broken and gently feparated, fpins out tranfparent filaments from the little cells that contained the clammy liquor of which thofe filaments were compofed. The natural fpunglafs then that fell at Ottaiano during this eruption, as well as that which fell in the ifle of Bourbon in the year 1766, must have been formed most probably by the operation of fuch a fort of lava as has been just described, cracking and feparating in the air at the time of its emiffion from the craters of the volcanos, and by that means fpinning out the pure vitrified matter from its pores or cells, the wind at the fame time carrying off those filaments of glafs as falt as they were produced. I obferved sticking to fome very large fragments of the new lava, which were of a close grain, some pieces of a fubftance, whofe texture very much refembled that of a true pumice-ftone; and upon a a half high, and feventy-two feet in clofe clofe examination, and having feparated them from the lava, I perceived that this fubftance had actually been forced out of the minute pores of the folid ftone itself, and was a collection of fine vitreous fibres or filaments, confounded together at the time of their being preffed out by the contraction of the large fragments of lava in cooling, and which had bent downwards by their own weight. This curious fubftance has the lightness of a pumice, and refembles it in every respect, except being of a darker colour. When the pores of the fresh folid lava were large and filled with pure vitrified matter, we found that matter fometimes blown into bubbles on its furface, I fuppofe by the air which had been forced out at the time the lava contracted it felf in cooling: thofe bubbles being thin, fhewed that this volcanic glafs has the kind of transparency of our common glass bottles, and is like them of a dirty yellow colour. I detached with a hammer fome large pieces of this kind of glafs, as big as my fift, which adhered to, and was incorporated with, fome of the larger fragments of lava, and, though of the fame kind, from their thicknefs they appeared perfectly black, and were opaque. Another particularity is remarkable in the lava of this eruption : many detached pieces of it are in the fhape of a barley-corn, or of a plumb-ftone, fmall at each end, and thick in the middle. We picked up feveral, and faw many more which were too heavy for us to carry off, for they must have weighed more than fixty pounds; fome of the smaller ones did not weigh an ounce. I fuppofe them to be drops from the liquid fountain of fire of the 8th of Auguft, which might very naturally acquire fuch a form in their fall; but the peasants in the neighbourhood of Vefuvius are well convinced that they are the thunder-bolts that fell with the volcanic lightning. We found many of the volcanic bombs, or, properly speaking, round balls of fresh lava, large and fmall; all of which have a nucleus, compofed of a fragment of more ancient and folid lava. There were alfo fome other curious vitrifications, very different from any I had ever feen before, mixed with the late fallen fhower of huge fcoria and maffes of lava. Though I have endeavoured to be as particular and clear as poffible in the defcription I have given of the curious fubftances produced by the late eruption of Vefuvius, yet, as fpecimens of thofe fubftances will explain more at one fight than I can pretend to do by whole pages in writing, I fhall not fail to fend you, by the first favourable opportunity, a collection of them, which I have fet apart for that purpose, particularly as I flatter myself they may ferve to give fome light into a hitherto obfcure fubject: I mean, the nature and manner of the formation of pumiceftones. Vefuvius continues to fmoke confiderably, and we had a flight fhock of an earthquake yesterday; fo that I do not think, notwithftanding the late eruptions having been fo very confiderable, that the volcano has vented itfelf fo fufficiently as to remain long quiet. I must now, Sir, beg your pardon if I have trefpaffed too much upon upon your time: I meant to be fhort, clear, and explicit; and if, by aiming at the two latter, I have failed in the former, I hope I fhall be excufed, and that you will please to take the will for the deed. I am, &c. Relation of the recent Eruption of Mount Etna. OWARDS the end of January, many reiterated fhocks of an earthquake were felt in different parts of Sicily; and from that time it was observed, that Etna emitted a thick fmoke from its center, which extended commonly to the eaft. A new eminence was next obferved on the western fide of the mountain, vifible at the distance of more than 50 miles, the certain fign of a local explofion. The 28th of March and the 8th of April, the earthquakes were felt with more violence, in direction from north to south, and the smoke of the volcano augmented confiderably; infomuch that, on the 28th of April, it was perceived to rife from the crater in the form of a ftraight and lofty pine, its head loft in the clouds, and cafting out fmall fragments of a bituminous pumice-ftone to the circumference of more than twenty miles. This continued till the 17th of May, when the fmoke fuddenly ceafed. The 18th of May, towards noon, a violent fhock with a fubterraneous trembling was heard on the mountain, and at fix in the evening a mouth appeared at the foot of an ancient extinguished volcano, called Mount Frumento, very near the confines of the fecond region of Etna. The fire flowed from it like a river, and, entering a neighbouring valley, called Del Udfienza, it overran, in an inftant, the space of half a league in the plain del Carpintero and delle Mandre del Favo, and then precipitated itself into the valley del Neve, rifing to the height of a hundred feet. At nine o'clock the mountain opened at two places lower ftill, on the land called li Scoperti di Palermo. These two openings, being very near each other, foon formed but one, the fire taking a direction to the weft, where the firft lava flowed. They each united in the plain called de Santi, and overran the space of one third of a mile. The firft lava again feparated itself from the others, continuing its courfe alone in the valley del Udfienza, where it flowed again, although more flowly, threatening the country of la Malta, and the lands of the Cavalier, which belong to the Benedictines of Catania. The two other lavas took a direction towards Mount Parmentelli; the base of which, to the extent of about two miles, they quite furrounded, then flowing by the east of Mount del Mazzo, they extended along the vineyards of Rugalira, and, after having fucceffively overrun the space of three leagues, they ftopped on the 25th of May. The greatest breadth of this branch was one mile, and its elevation about five feet. During the night of the 26th, a new mouth opened at the foot of Mount Parmentelli, in the middle of the lava. This volcano, for more than an hour, threw out ftones of a prodigious fize, and to |