After having passed at least three hours on the crater, we descended, and went to a rising ground, about a mile distant from the upper mountain we had just left, and saw there some remains of the foundation of an ancient building; it is of brick, and seems to have been ornamented with white marble, many fragments of which are scattered about. It is called the Philosopher's Tower, and is said to have been inhabited by Empedocles. As the ancients used to sacrifice to the celestial gods on the top of Etna[23], it may very well be the ruin of a temple that served for that purpose. From hence we went a little further over the inclined plain abovementioned, and saw the evident marks of a dreadful torrent of hot water, that came out of the great crater at the time of an eruption of lava in the year 1755, and upon which phænomenon the Canonico Recupero, our guide, has published a dissertation. Luckily this torrent did not take its course over the inhabited parts of the mountain; as a like accident on Mount Vesuvius in 1631 swept away some towns and villages in its neighbourhood, with thousands of their inhabitants. The common received opinion is, that these eruptions of water proceed from the Volcanos having a communication with the sea; but I rather believe them to proceed merely from depositions of rain water in some of the inward cavities of them. We likewise saw from hence the whole course of ancient lava, the most considerable as to its extent of any known here; it ran into the sea near Taormina, which is not less than thirty miles from the crater whence it issued, and is in many parts fifteen miles in breadth. As the lavas of Etna are very commonly fifteen and twenty miles in length, six or seven in breadth, and fifty feet or more in depth; you may judge, Sir, of the prodigious quantities of matter emitted in a great eruption of this mountain, and of the vast cavities there must necessarily be within its bowels. The most extensive lavas of Vesuvius do not exceed seven miles in length. The operations of nature on the one mountain and the other are certainly the same; but on Mount Etna, all are upon a great scale. As to the nature and quality of their lavas, they are much the same; but I think those of Etna rather blacker, and in general more porous, than those of Vesuvius. In the parts of Etna that we went over, I saw no stratas of pumice stones, which are frequent near Vesuvius, and cover the ancient city of Pompeii; but our guide told us, that there are such in other parts of the mountain. I saw some stratas of what is called here tufa; it is the same that covers Herculaneum, and that composes most of the high grounds about Naples; it is, upon examination, a mixture of small pumice stones, ashes, and fragments of lava, which is by time hardened into a sort of stone[24]. In short, I found, with respect to the matter erupted, nothing on Mount Etna that Vesuvius does not produce; and there certainly is a much greater variety in the erupted matter and lavas of the latter, than of the former; both abound with pyrites and crystallizations, or rather vitrifications. The sea shore at the foot of Etna, indeed, abounds with amber, of which there is none found at the foot of Vesuvius. At present there is a much greater quantity of sulphur and salts on the top of Vesuvius than on that of Etna; but this circumstance varies according to the degree of fermentation within; and our guide assured me, he had seen greater quantities on Etna at other times. In our way back to Catania, the Canon shewed me a little hill, covered with vines, which belonged to the Jesuits, and, as is well attested, was undermined by the lava in the year 1669, and transported half a mile from the place where it stood, without having damaged the vines.
In great eruptions of Etna, the same sort of lightning, as described in my account of the last eruption of Vesuvius, has been frequently seen to issue from the smoak of its great crater. The antients took notice of the same phænomenon; for Seneca (lib. ii. Nat. Quæst.) says,—"Ætna aliquando multo igne abundavit, ingentem vim arenæ urentis effudit, involutus est dies pulvere, populosque subita nox terruit, illo tempore aiunt plurima fuisse tonitrua et fulmina."
Till the year 252 of Christ, the chronological accounts of the eruptions of Etna are very imperfect: but as the veil of St. Agatha was in that year first opposed to check the violence of the torrents of lava, and has ever since been produced at the time of great eruptions; the miracles attributed to its influence, having been carefully recorded by the priests, have at least preserved the dates of such eruptions. The relicks of St. Januarius have rendered the same service to the lovers of natural history, by recording the great eruptions of Vesuvius. I find, by the dates of the eruptions of Etna, that it is as irregular and uncertain in its operations as Vesuvius[25]. The last eruption was in 1766.
On our return from Messina to Naples, we were becalmed three days in the midst of the Lipari islands, by which we had an opportunity of seeing that they have all been evidently formed by explosion[26]; one of them, called Vulcano, is in the same state as the Solfaterra. Stromboli is a Volcano, existing in all its force, and, in its form of course, is the most pyramidal of all the Lipari Islands; we saw it throw up red hot stones from its crater frequently, and some small streams of lava issued from its side, and ran into the sea[27]. This Volcano differs from Etna and Vesuvius, by its continually emitting fire, and seldom any lava; notwithstanding its continual explosions, this island is inhabited, on one side, by about an hundred families.
These, as well as I can recollect, are all the observations that I made with respect to Volcanos, in may late curious tour of Sicily; and I shall be very happy should the communication of them afford you, or any of our countrymen (lovers of natural history) satisfaction or entertainment.
I am,
Sir,
With great regard and esteem,
Your most obedient
humble servant,
W. Hamilton.