The annual register or a view of the history, politics and literature for the year 1772,
London 1773
There fertile and pleasant island of Procita shews also most evident signs of its soil being directly similar to that of Baia and Puzzole; this island seems really, as was imagined by the ancients, to have been detached from the neighbouring island of Ischia.
There is no spot, I believe, that could afford a more ample field for curious observations, than the island of Ischia, called Enaria, Inarime, and Pithecusa, by the ancients. I have visited it three times; and this summer passed three weeks there, during which time, I examined with attention, every part of it. Ischia is eighteen miles in circumference: the whole of its soil is the same as that near Vesuvius, Naples, and Puzzole. There are numberless springs, hot, warm, and cold, dispersed over the whole island, the waters of which are impregnated with minerals of various sorts; so that, if you give credit to the inhabitants of the country, there is no disorder but what finds its remedy here. In the hot months (the season for making use of these baths), those who have occasion for them stock hither from Naples. A charitable institution sends and maintains three hundred poor patients at the baths of Gurgitelli every season. By what I could learn of these poor patients, those baths have really done wonders, in cases attended with obstinate tumours, and in contractions of the tendons ad muscles. The patient begins b y bathing, and then is buried in the hot sand near the sea. In many parts of the island, the sand is burning hot, even under water. The sand on some parts of the shore is almost entirely composed of particles of iron ore; at least they are attracted by the loadstone, as I have experienced. Near that part of the island called Lacco, there is a rock of an ancient lava, forming a small cavern, which is shut up with a door; this cavern is made use of to cool liquors and fruit, which it does in a short time as effectually as ice. Before the door was opened, I felt the cold to my legs very sensibly; but when it was opened, the cold rushed out so as to give me pain, and within the grotto it was intolerable. I was not sensible of wind attending this cold; though upon mount Etna and mount Vesuvius, where there are caverns of this kind, the cold is evidently occasioned by a subterraneous wind: the natives call such places ventaroli. May not the quantity of nitre, with which all there places abound, account in some measure for such extreme cold. My thermometer was unluckily broken, or I would have informed you of the exact degree of the cold in this ventaroli of Ischia, which is by much the strongest in its effects I ever felt. The ancient lavas of Ischia shew, that the eruptions there have been very formidable; and, history informs us, that its first inhabitants were driven out of the island by the frequency and the violence of them. There are some of these ancient lavas not less than two hundred feet in depth.
The mountain of St. Nicola, on which there is at present a convent of hermits, was called by the ancients Epomeus; it is as high, if not higher, than Vesuvius, and appears to me to be a section of the cone of the ancient and principal volcano of the island, its composition being all tufa or lava. Tile cells of the convent abovementioned are cut out of the mountain itself; and there you fee plainly that its composition no way differs from the matter that covers Herculaneum, and forms the Monte Nuovo. There is no sign of a crater on the top of this mountain, which rises almost to a sharp point; time, and other accidents, may be reasonably supposed to have worn away this distinctive mask of its having been formed evidently by explosion, on the flanks of Etna and Vesuvius. Strabo, in his 5th book upon the subject of this island, quotes Timaeus, as having said, that, a little before his time, a mountain in the middle of Pithecusa, called Epomeus, was shook by an earthquake, and vomitecl flames.
There are many other rising grounds in this island, that, from the nature of their composition, must lead one to think the same as to their origin. Near the village of Castiglione, there is a mountain formed surely by an explosion of a much later date, having preserved its conical form and crater entire, and producing as yet but a slender vegetation: there is no account, however, of the date of this eruption. Nearer the town of Ischia, which is on the sea shore, at a place called Le Cremate, there is a crater, from which, in the year 1301 or 1302, a lava ran quite into the sea ; there is not the least vegetation on this lava, but it is nearly in the same state as the. modern lava of Vesuvius. Pontano, Maranti, and D. Francesco Lombardi, have recorded this eruption; the latter of whom says, that it lasted two months, that many men and beasts were killed by the explosion, and that a number of the inhabitants were obliged to seek for refuge at Naples and in the neighbouring islands. In short, according to my idea, the island of Ischia must have taken its rise from the bottom of the sea, and been increased to its present size by divers later explosions. This is not extraordinary, when history tells us 8and from my own observation I have reason to believe) that the Lipary islands were formed in the like manner. There has been no eruption in Ischia since that just mentioned, but earthquakes are very frequent there; two years ago, as I told, they had a very considerable shock of an earthquake in this island.