Observations on Mount Vesuvius, Mount Etna, and Other Volcanos

by Sir William Hamilton

We passed through the inferior district of the mountain, called by its inhabitants La Regione Piemontese. It is well watered, exceedingly fertile, and abounding with vines and other fruit trees, where the lava, or, as it is called there, the sciara, has had time to soften, and gather soil sufficient for vegetation, which, I am convinced from many observations, unless assisted by art, does not come to pass for many ages[18], perhaps a thousand years or more; the circuit of this lower region, forming the basis of the great Volcano, is upwards of one hundred Italian miles. The vines of Etna are kept low, quite the reverse of those on the borders of Vesuvius; and they produce a stronger wine, but not in so great abundance. The Piemontese district is covered with towns, villages, monasteries, &c. and is well peopled, notwithstanding the danger of such a situation. Catania, so often destroyed by eruptions of Etna, and totally overthrown by an earthquake towards the end of the last century[19], has been re-built within these fifty years, and is now a considerable town, with at least thirty-five thousand inhabitants. I do not wonder at the seeming security with which these parts are inhabited, having been so long witness to the same near Mount Vesuvius. The operations of Nature are slow: great eruptions do not frequently happen; each flatters himself it will not happen in his time, or, if it should, that his tutelar saint will turn away the destructive lava from his grounds; and indeed the great fertility in the neighbourhoods of Volcanos tempts people to inhabit them.

In about four hours of gradual ascent, we arrived at a little convent of Benedictine monks, called St. Nicolo dell' Arena, about thirteen miles from Catania, and within a mile of the Volcano from whence issued the last very great eruption in the year 1669; a circumstantial account of which was sent to our court by a Lord Winchelsea, who happened to be then at Catania in his way home, from his embassy at Constantinople. His Lordship's account is curious, and was printed in London soon after; I saw a copy of it at Palermo, in the library of the Prince Torremuzzo[20]. We slept in the Benedictines convent the night of the 24th, and passed the next morning in observing the ravage made by the abovementioned terrible eruption, over the rich country of the Piemontese. The lava burst out of a vineyard within a mile of St. Nicolo, and, by frequent explosions of stones and ashes, raised there a mountain, which, as near as I can judge, having ascended it, is not less than half a mile perpendicular in height, and is certainly at least three miles in circumference at its basis. The lava that ran from it, and on which there are as yet no signs of vegetation, is fourteen miles in length, and in many parts six in breadth; it reached Catania, and destroyed part of its walls, buried an amphitheatre, an aqueduct, and many other monuments of its ancient grandeur, which till then had resisted the hand of Time, and ran a considerable length into the sea, so as to have once formed a beautiful and safe harbour; but it was soon after filled up by a fresh torrent of the same inflamed matter: a circumstance the Catanians lament to this day, as they are without a port. There has been no such eruption since, though there are signs of many, more terrible, that have preceded it.

For two or three miles round the mountain raised by this eruption, all is barren, and covered with ashes; this ground, as well as the mountain itself, will in time certainly be as fertile as many other mountains in its neighbourhood, that have been likewise formed by explosion. If the dates of these explosions could be ascertained, it would be very curious, and mark the progress of time with respect to the return of vegetation, as the mountains raised by them are in different states; those which I imagine to be the most modern are covered with ashes only; others of an older date, with small plants and herbs; and the most ancient, with the largest timber-trees I ever saw: but I believe the latter are so very ancient, as to be far out of the reach of history. At the foot of the mountain, raised by the eruption of the year 1669, there is a hole, through which, by means of a rope, we descended into several subterraneous caverns, branching out and extending much farther and deeper than we chose to venture; the cold there being excessive, and a violent wind frequently extinguishing some of our torches. These caverns undoubtedly contained the lava that issued forth, and extended, as I said before, quite to Catania. There are many of these subterraneous cavities known, on other parts of Etna; such as that called by the peasants La Baracca Vecchia, another La Spelonca della Palomba (from the wild pigeons building their nests therein), and the cavern Thalia, mentioned by Boccaccio. Some of them are made use of as magazines for snow; the whole island of Sicily and Malta being supplied with this essential article (in a hot climate) from Mount Etna. Many more would be found, I dare say, if searched for, particularly near and under the craters from whence great lavas have issued, as the immense quantities of such matter we see above ground, must necessarily suppose very great hollows underneath.

After having passed the morning of the 25th in these observations, we proceeded through the second or middle region of Etna, called La Selvosa, the woody, than which nothing can be more beautiful. On every side are mountains, or fragments of mountains, that have been thrown up by various ancient explosions; there are some near as high as Mount Vesuvius; one in particular (as the Canon our guide assured me, having measured it) is little less than one mile in perpendicular height, and five in circumference at its basis. They are all more or less covered, even within their craters, as well as the rich vallies between them, with the largest oak, chesnut, and firr trees, I ever saw any where; and indeed it is from hence chiefly, that his Sicilian Majesty's dockyards are supplied with timber. As this part of Etna was famous for its timber in the time of the Tyrants of Syracusa, and as it requires the great length of time I have already mentioned before the matter is fit for vegetation, we may conceive the great age of this respectable Volcano. The chesnut-trees predominated in the parts through which we passed, and, though of a very great size, are not to be compared to some on another part of the Regione Selvosa, called Carpinetto. I have been told by many, and particularly by our guide, who had measured the largest there, called La Castagna Cento Cavalli, that it is upwards of twenty-eight Neapolitan canes in circumference. Now as a Neapolitan cane is two yards and half a quarter, English measure, you may judge, Sir, of the immense size of this famous tree[21]. It is hollow from age, but there is another near it almost as large and sound. As it would have required a journey of two days to have visited this extraordinary tree, and the weather being already very hot, I did not see it. It is amazing to me, that trees should flourish in so shallow a soil; for they cannot penetrate deep without meeting with a rock of lava; and indeed great part of the roots of the large trees we passed by are above ground, and have acquired, by the impression of the air, a bark like that of their branches. In this part of the mountain, are the finest horned cattle in Sicily; we remarked in general, that the horns of the Sicilian cattle are near twice the size of any we had ever seen; the cattle themselves are of the common size. We passed by the lava of the last eruption in the year 1766, which has destroyed above four miles square of the beautiful wood abovementioned. The mountain raised by this eruption abounds with sulphur and salts, exactly resembling those of Vesuvius; specimens of which I sent some time ago to the late Lord Morton.

In about five hours from the time we had left the convent of St. Nicolo dell' Arena, we arrived at the borders of the third region, called La Netta, or Scoperta, clean or uncovered, where we found a very sharp air indeed; so that, in the same day, the four seasons of the year were sensibly felt by us, on this mountain; excessive summer heats in the Piemontese, spring and autumn temperature in the middle, and extreme cold of winter in the upper region. I could perceive, as we approached the latter, a gradual decrease of vegetation; and from large timber trees we came to the small shrubs and plants of the northern climates: I observed quantities of juniper and tanzey; our guide told us that later in the season there are numberless curious plants here, and that in some parts there are rhubarb and saffron in plenty. In Carrera's History of Catania, there is a list of all the plants and herbs of Etna in alphabetical order.

Night coming on, we here pitched a tent, and made a good fire, which was very necessary; for without it, and very warm cloathing, we should surely have perished with cold; and at one of the clock in the morning of the 26th, we pursued our journey towards the great crater. We passed over vallies of snow, that never melts, except there is an eruption of lava from the upper crater, which scarcely ever happens; the great eruptions are usually from the middle region, the inflamed matter finding (as I suppose) its passage through some weak part, long before it can rise to the excessive height of the upper region, the great mouth on the summit only serving as a common chimney to the Volcano. In many places the snow is covered with a bed of ashes, thrown out of the crater, and the sun melting it in some parts makes this ground treacherous; but as we had with us, besides our guide, a peasant well accustomed to these vallies, we arrived safe at the foot of the little mountain of ashes that crowns Etna, about an hour before the rising of the sun. This mountain is situated in a gently inclining plain of about nine miles in circumference; it is about a quarter of a mile perpendicular in height, very steep, but not quite so steep as Vesuvius; it has been thrown up within these twenty-five or thirty years, as many people at Catania have told me they remembered when there was only a large chasm or crater, in the midst of the abovementioned plain. Till now, the ascent had been so gradual (for the top of Etna is not less than thirty miles from Catania, from whence the ascent begins) as not to have been the least fatiguing; and if it had not been for the snow, we might have rode upon our mules to the very foot of the little mountain, higher than which the Canon our guide had never been: but as I saw that this little mountain was composed in the same manner as the top of Vesuvius, which, notwithstanding the smoak issuing from every pore, is solid and firm, I made no scruple of going up to the edge of the crater; and my companions followed. The steep ascent, the keenness of the air, the vapours of the sulphur, and the violence of the wind, which obliged us several times to throw ourselves flat upon our faces to avoid being overturned by it, made this latter part of our expedition rather inconvenient and disagreeable. Our guide, by way of comfort, assured us, that there was generally much more wind in the upper region at this time.

Soon after we had seated ourselves on the highest point of Etna, the sun arose, and displayed a scene that indeed passes all description. The horizon lighting up by degrees, we discovered the greatest part of Calabria, and the sea on the other side of it; the Phare of Messina, the Lipari Islands; Stromboli, with its smoaking top, though at above seventy miles distance, seemed to be just under our feet; we saw the whole island of Sicily, its rivers, towns, harbours, &c. as if we had been looking on a map. The island of Malta is low ground, and there was a haziness in that part of the horizon, so that we could not discern it; our guide assured us, he had seen it distinctly at other times, which I can believe, as in other parts of the horizon, that were not hazy, we saw to a much greater distance; besides, we had a clear view of Etna's top from our ship, as we were going into the mouth of the harbour of Malta some weeks before; in short, as I have since measured on a good chart, we took in at one view a circle of above nine hundred English miles. The pyramidal shadow of the mountain reached across the whole island, and far into the sea on the other side. I counted from hence forty-four little mountains (little I call them in comparison of their mother Etna, though they would appear great any where else) in the middle region on the Catania side, and many others on the other side of the mountain, all of a conical form, and each having its crater; many with timber trees flourishing both within and without their craters. The points of those mountains that I imagine to be the most ancient are blunted, and the craters of course more extensive and less deep than those of the mountains formed by explosions of a later date, and which preserve their pyramidal form entire. Some have been so far mouldered down by time, as to have no other appearance of a crater than a sort of dimple or hollow on their rounded tops, others with only half or a third part of their cone standing; the parts that are wanting having mouldered down, or perhaps been detached from them by earthquakes, which are here very frequent. All however have been evidently raised by explosion; and I believe, upon examination, many of the whimsical shapes of mountains in other parts of the world would prove to have been occasioned by the same natural operations. I observed that these mountains were generally in lines or ridges; they have mostly a fracture on one side, the same as in the little mountains raised by explosion on the sides of Vesuvius, of which there are eight or nine. This fracture is occasioned by the lava's forcing its way out, which operation I have described in my account of the last eruption of Vesuvius. Whenever I shall meet with a mountain, in any part of the world, whose form is regularly conical, with a hollow crater on its top, and one side broken, I shall be apt to decide such a mountain's having been formed by an eruption; as both on Etna and Vesuvius the mountains formed by explosion are without exception according to this description. But to return to my narrative.

After having feasted our eyes with the glorious prospect above-mentioned (for which, as Spartian tells us, the Emperor Adrian was at the trouble of ascending Etna), we looked into the great crater, which, as near as we could judge, is about two miles and a half in circumference; we did not think it safe to go round and measure it, as some parts seemed to be very tender ground. The inside of the crater, which is incrusted with salts and sulphurs like that of Vesuvius, is in the form of an inverted hollow cone, and its depth nearly answers to the height of the little mountain that crowns the great Volcano. The smoak, issuing abundantly from the sides and bottom, prevented our seeing quite down; but the wind clearing away the smoak from time to time, I saw this inverted cone contracted almost to a point; and, from repeated observations, I dare say, that in all Volcanos, the depth of the craters will be found to correspond nearly to the height of the conical mountains of cinders which usually crown them; in short, I look upon the craters as a sort of suspended funnels, under which are vast caverns and abysses. The formation of such conical mountains with their craters are easily accounted for, by the fall of the stones, cinders, and ashes, emitted at the time of an eruption.

The smoak of Etna, though very sulphureous, did not appear to me so fetid and disagreeable as that of Vesuvius; but our guide told me, that its quality varies, as I know that of Vesuvius does, according to the quality of the matter then in motion within. The air was so very pure and keen in the whole upper region of Etna, and particularly in the most elevated parts of it, that we had a difficulty in respiration, and that, independent of the sulphureous vapour. I brought two barometers and a thermometer with me from Naples, intending to have left one with a person at the foot of the mountain, whilst we made our observation with the other, at sun-rising, on the summit; but one barometer was unluckily spoilt at sea, and I could find no one expert enough at Catania to repair it: what is extraordinary, I do not recollect having seen a barometer in any part of Sicily. At the foot of Etna, the 24th, when we made our first observation, the quicksilver stood at 27 degrees 4 lines; and the 26th, at the most elevated point of the Volcano, it was at 18 degrees 10 lines. The thermometer, on the first observation at the foot of the mountain was at 84 degrees, and on the second at the crater at 56[22]. The weather had not changed in any respect, and was equally fine and clear, the 24th and 26th. We found it difficult to manage our barometer in the extreme cold and high wind on the top of Etna; but, from the most exact observations we could make in our circumstances, the result was as abovementioned. The Canon assured me, that the perpendicular height of Mount Etna is something more than three Italian miles, and I verily believe it is so.