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fimes in three or four channels, regularly formed, down the flanks of the conical part of the volcano ; fometimes defcending and spreading itfelf in the valley between the two mountains; and once, when the eruption was in its greatest force, in the month of November laft, the lava defcended still lower, and did fome damage to the vine yards, and cultivated parts at the foot of Vefuvius, towards the vil lage of St. Sebaftiano; but generally the lava, not being abundant, ftopped and cooled before it was able to reach the valley. By the accumulation of thefe lavas on the flanks of Vefuvius, its form has been greatly altered; and by the frequent explofion of fcorie and afhes, a confiderable mountain has been formed within the crater, which now rifing much above its rim has likewife given that part of the mountain a new appearance. Juft before I left Naples, in May 1783, I was at the top of Vefuvius. The crater was certainly then more than 250 feet deep, and was impracticable, its fides being nearly perpendicular. This eruption, how ever, has been as fatisfactory as could be defired by the inhabitants of this city, a prodigious quantity of lava having been difgorged; which matter, confined within the bowels of the earth, would probably have occafioned tremors; and even flight ones might prove fatal to Naples, whofe houfes are, in general, very high, ill built, and a great number in almost every street already fupported by props, having either fuffered by former earthquakes, or from the loofe volcanic foil's having been washed from under their foundations by the torrents of rain water from the high grounds which furround Naples,
and on which a great part of the town itfelf is built.
"From the time of the last formidable eruption of Mount Vefuvius, in August 1779 (defcribed in one of my former communications to the Royal Society) to this day, I have, with the alliftance of the Father Antonio Piaggi, kept an exact diary of the operations of Vefuvius, with drawings, fhewing, by the quantity of finoke, the degrees of fermentation of the volcano; alfo the courfe of the lavas during this laft eruption, and the changes that have been made in the form of the mountain itself by the lavas and fcoriæ that have been ejected. This journal is becoming very curious and interefting; it is remarkably fo with refpect to the pointing out a variety of fingular effects that different currents of air have upon the fmoke that ifiues from the crater of Vefuvius, elevated more than 3600 feet above the level of the fea; bur, except the fmoke increafing confiderably and conftantly when the fea is agitated, and the wind blows from that quarter, the operations of Vefuvius appear to be very capricious and uncertain. One day there will be the appearance of a violent fermentation, and the next all is calmed again: but whenever the fmoke has been attended with confiderable ejections of fcoriæ and cinders, I have conftantly obferved, that the lava has foon after made its appearance, either by boiling over the crater, or forcing its paffage through crevices in the conical part of the volcano. As long as I remain in this country, and have the neceffary affift.nce of the above-mentioned ingenious monk (who is as excellent a draughtfman as he is an accurate and diligent G2
observer) the Vefuvian diary fhfl be continued; and I hope one day to have the honour of prefenting thefe curious manufcripts (which begin now to be voluminous) to the Royal Society, if it fhould think them worthy of a place in the library of the Society.
"Having never had an opportunity of examining the islands of Ponza, Palmarole, Zannone, and other small islands, or rather rocks, fituated between the island of Ventotiene and Monte Circello, near Teracina, on the continent; and thinking that by a tour of thofe iflands I fhould be enabled to render my former obfervations more complete, and to communicate fome account of the only volcanic parts of this neighbourhood hitherto undefcribed, I determined to take advantage of the abfence of their Sicilian majefties (who were then making the tour of Italy) and vifit these iflands. But before I put this plan in execution, I made a long excurfion in the province of Abruzzo, as far as the lake of Celano, anciently called Fucinus, and where the famous emiffary of the emperor Claudius (a molt ftupendous work for draining that lake) remains nearly entire, though filled up with rub. bith and earth in many parts, and of courfe ufelefs. The water of this lake, which is more than 30 miles in circumference, increafes daily, and is destroying the rich and cultivated plains on its borders. It is furrounded by very high mountains, many of them covered with fnow, and at the foot of them are many villages, and rich and well cultivated farms. Upon the whole, it is the most beautiful lake I ever faw, and would be complete, if the neighbouring mountains were better wooded. This
lake furnishes abundance of fih, but not of the best quality: a few large trout, but moftly tench, barbel, and dace. In the fhallow water on the borders of the lake, I faw thousands of water fnakes, purfuing and preying upon little fifh like our thornbacks, but much better armed, though their deferfive weapons feemed to avail them but little against fuch ravenous foes.
"I went with torches into the emiffary of Claudius as far as I could. It is a covered underground canal, three miles long, and great part of it cut through a hard rock; the other part fupported by mafonry, with wells funk to give air and light. According to Suetonius, Claudius employed 30 thoufand men eleven years on this great work, intended to convey the fuperfluous water of the lake into the bed of the river Liris, now called Garigliano; and I make no doubt, but that if it was cleared and repaired, it would again anfwer that purpose.
"In its prefent flate it is a most magnificent monument of antiquity.
"The whole country from Arpino, the native place of Marius, by Ifola, Sora, Civitella, and Capirello, to the lake of Celano, is, in my opinion, infinitely more beautiful and picturefque than any fpot I have yet feen on the Alps, in Savoy, Switzerland, or the Tyrol. The road is not paffable for carriages, and indeed is fcarcely fo, even in fummer, for horfes or mules, and is often infested with banditti; a party of which, confiling of twenty-two, had quartered themfelves in a village which I pafled through, and left it but a week before my arrival. There are many wolves, and fome bears
in the adjacent mountains, which alfo commit their depredations in the winter. The tyger-cat, gattopardo, or lynx, is fometimes found in the woods of this part of Abruzzo.
"The road follows the windings of the Garigliano, which is here a beautiful clear trout stream, with a great variety of cafcades and water-falls, particularly a double one at Ifola, near which place Cicero had a villa, and there are still fome remains of it, though converted to a chapel. a chapel. The valley is extenfive, and rich with fruit trees, corn, vines, and olives. Large tracts of land are here and there covered with woods of oak and chestnut, all timber trees of the largest fize. The mountains nearest the valley rife gently, and are adorned with either modern caftles, towns, and villages, or the ruins of ancient ones. The next range of mountains, rifing behind thefe, are covered with pines, larches, and fuch trees and fhrubs as ufually abound in a like fituation: and above them a third range of mountains and rocks, being the moft elevated part of the Apennine, rife much higher, and, being covered with eternal fnow, make a beautiful contraft with the rich valley above mentioned; and the fnow is at fo great a distance, as not to give that uncomfortable chill to the air, which I have always found in the narrow vallies of the Alps and the Tyrol.
"On the 15th of Auguft laft I went in a felucca to the ifland of Ifchia. I have nothing to add to my former obfervations on this ifland, already communicated to the Royal Society, except that about fixty yards from the fhore, at a place called St. Angelo, fituated between the towns of Ifchia and
Furia, a column of boiling water bubbles upon the furface of the fea with great force, and communicates its heat to the water of the fea near it; but as the wind was very high, and the furf confiderable, I was not able then to examine this curious fpot as I could have wifhe, but will return there on purpose fome other time. The inhabitants of the neighbourhood told me, that it always boiled up in the fame manner, winter and fummer; and that it was of great ufe to them in bending their planks for fhipbuilding; and that the fishermen alfo frequently made ufe of this natural cauldron to boil their fifh. Though I have paffed at different times many weeks in the island of Ifchia, I never before heard of this phænomenon: but in my defcription of this ifland mention is made of feveral fpots where, near the fhore, I had found, when bathing in the fea, the fand under my feet fo hot as to oblige me to retire haftily. This boiling spring reminds me of one near Viterbo in the Roman State, which I have feen, and is called the Bulicame. It is a circular pool of about fixty feet in diameter, and exceedingly deep, the water of which is conftantly boiling. It is fituated in a plain furrounded by volcanic mountains. A tony concretion floats on the furface of the pool, which being carried off by the fuperfluous water is depofited, and is conftantly forming a labes or tuffa, of which all the foil around the pool is composed.
"The 18th of Auguft I arrived at the ifland of Ventotiene, about twenty-five miles from Ifchia. It is greatly improved fince my former vifit, feven or eight yea's ago, when his Sicilian majefty first planted a little colony there. It G 3
then produced neither corn nor wine; now it furnishes annually at least seventy butts of wine and two thousand tomoli of corn. The foil is remarkably fertile, from whence it probably took its ancient Greek name of Pandataria. This ifland contains at prefent more than three hundred inhabitants. I will mention a curious circumftance in the natural history of birds, of which I was informed by an officer of the garrifon of Ventotiene who is a great fportfman, and fhoots often in the island of St. Stefano, inhabited only by hawks, and a large kind of fea-gulls; but is occafionally vifited, as a refting place by divers forts of birds of pafiage. In the month of May great flights of quails arrive there from Africa, fpent with fatigue; and many of them fall an eafy prey for the hawks and fea gulls; but, as their arrival depends upon one prevailing wind, there is often an interval of many days between one flight and another. My informer affured me, that the hawks conftantly, during the flights, make a provifion of each day's prey, laying them up in feparate heaps of fix or feven near their haunts, always feeding first upon those of the oldeft date. The fea gulls have not the fame forefight, but geedily fall upon their unhappy victims in their languid ftate before they reach the fhore, and, having beat them down into the fea, fwallow numbers of them whole. Extraordinary as this may appear, yet as facts related by perfons of credibility in any branch of natural history are always pleafing, I thought you would excufe this digreffion. Give me leave likewise to add, for the information of the curious in antiquities, that, during my stay in the island of Ventotiene,
I got out of the ruins of an elegant ancient bath (supposed to have been built for the ufe of Julia, daughter of Auguftus, whilst the was in exile here) a fragment of a tile, on which are ftamped the following characters in basso relievo,
which, according to the interpretation of a celebrated antiquary at Naples, mean Opus Hacini ad commodum Balnei Julia Augufte factum. I was informed, that feveral entire tiles, with a like infcription, had been dug up on the fame fpot, and had been made use of in building the church and barracks newly erected in this island. Another fragment of a tile was likewife found here, and given to me, with the following infcription:
which the fame antiquary explains, Sabine Augufta, Piæ Imperatrici dicatum Balneum; but, I believe, there is no mention, in ancient authors of Sabina having been at Pandataria: of Julia's banishment to this ifland there can be no doubt.
"Between Ventotiene and the ifland of Ponza, and from the latter at the distance of about twelve miles, a group of rocks rise several feet above the furface of the sea, They are called the Botte, and are compofed of a compact lava; probably they are the fmall remains of another volcanic island, the fofter parts of which may have been carried off and levelled by the action of the fea, which is open and violent here.
"The 20th of August I arrived at the ifland of Ponza, about thirty miles from Ventotiene, and the next day I went round it in
my boat. It is near five miles long its greatest breadth not more than half a mile, and in fome parts not more than five hundred feet. It is furrounded by innumerable detached rocks, fome of them very high, and most of which are of lava; in many are regularly formed bafaltes, but none in large columns. In fome parts the bafaltes have a reddish tint of iron ochre, are very small, and irregularly laid one over another. Some maffes of them are in a perpendicular, others in an horizontal, and others again in an inclined pofition: and the rocks themfelves, in which these maffes are found, are lava of the fame nature as the bafaltes. At first fight thefe rocks have very much the appearance of the ruins of ancient Roman brick or rather tile buildings. One rock is compofed of large spherical bafaltes; and in many parts of the island I found the lava had inclined to take the like spherical form, though on a much smaller fcale, fome of the first mentioned round bafaltes being near two feet in diameter. All these rocks have certainly been detached by the action of the fea from the island, which is entirely compofed of volcanic matter, lava's, and tuffa's, of various qualities and tints, green, yellow, black, and white. Some of the tuffa's, as well as the lava's, are of a texture more compact than others; and in fome parts of the island great tracts feem to have undergone the fame operation as is in full force at a fpot called the Pifciarelli; on the outfide of the Solfaterra, near Puzzole, and where a hot fulphureous vitriolic acid vapour converts all which it penetrates, whether lava's, tuffa's, volcanic afles, or pumice ftones, into a pure clay,
mofly white, or with a light tint of red, blue, green, or yellow.
"In one part of the illand there is a fort of tuffa, remarkably good for the purpofe of building. It is as hard as our Bath ftone, and nearly of the fame colour, without any mixture of fragments of lava or pumice ftone, which ufually abound in the tuffa's in the neighbourhood of Naples, Baia, and Puzzole.
"When I was last in England, I enquired of many of the manufacturers of glafs, whether it had ever happened, that the glafs, cooling in their furnaces had taken any diftinct forms like prifms or cryftallizations; but I got no fatisfactory answer until I applied to the ingenious Mr. Parker, of Flectftreet, who not only informed me, that, fome years ago, a quantity of his flint glafs had been rendered unferviceable by taking fuch a form in cooling; but alfo gave me feveral curious fpecimens of the glass itself; fome of them are in lamine, which may be cafily feparated; and others refemble balfaltic columns in miniature, having regular faces. I was much pleafed with this difcovery, proving to me beyond a doubt, the volcanic origin of moft bafaltes. Many of the rocks of lava of the ifland of Ponza are, with refpect to their configu rations, ftrikingly like the specimens of Mr. Parker's above mentioned glafs, none being very regularly formed bafaltes, but all having a tendency towards it. Mr. Parker could not account for the accident that occafioned his glafs to take the bafaltic forms; but I have remarked both in Sicily and at Naples, that fuch lavas as have run into the fea, are either formed into regular bafaltes, or have a G 4