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Popular Science Monthly/Volume 46/March 1895/The Birth of a Sicilian Volcano

THE

POPULAR SCIENCE

MONTHLY.

 

MARCH, 1895.


 

THE BIRTH OF A SICILIAN VOLCANO.
By Prof. A. S. PACKARD.

OUR hope in planning a brief journey to Sicily was to ascend Mount Etna, which, as everybody knows, is the highest volcano in Europe, and whose history and appearance have been recorded from the days of Homer. Although we did not ascend to the very summit, we had the unexpected pleasure of tramping up the ash-cone of one of the many minor volcanoes or monticles which stud the flanks of the majestic mother volcano, who looks down from her serene heights upon a numerous progeny scattered about her skirts.

Monte Gemellaro is the youngest of the brood. It is situated four thousand six hundred and fifty feet above the Mediterranean, and the crater itself is four hundred and fifty feet in height above the side of the parent mountain.

This symmetrical, double-headed cone, too recently upheaved to have been much despoiled by rains and frosts, suddenly appeared after a few days' disturbance, and nearly each stage in its rapid development was studied by experienced observers, or at least in a more careful manner than any of its predecessors, since so much more attention than formerly is now paid to the study of volcanism.

In May, 1886, just three years previous to our visit, and within the short period of twelve days—days of fear and suspense to the inhabitants of the hamlets and villages below—the cone was formed by the upheaval of great masses of lava, ashes, and slag, accompanied with clouds of steam and deadly gases, the lava stream threatening Nicolosi, the highest town on the flanks of Etna, and which during the eruption of 1069 was leveled to the ground. Then a period of rest and quiet ensued, and the scene three years later was one of utter desolation, the eye within a radius of two or three miles resting only on vast wastes of volcanic sand, slag, and ashes, with the rugged wild lava streams below.

Late in the afternoon of a day in the middle of April we left Naples, then cold and raining, with thunder and lightning; and after a particularly rough and disagreeable night in a steamer without ballast, which bobbed about on the chopping sea like a cork, we landed early in the morning at Palermo. The day was spent in visiting the fine zoölogical museum, and in wandering through the attractive botanical garden of that beautiful city.

The traveler who would see Etna to the best advantage should approach it from the west and south as well as the north. Leaving Palermo the next morning by an early train we soon reached the junction of Termini. At this point the railroad turns south and runs into the interior; but before we left the coast we could see, some eighty miles distant, heavy clouds of steam and ashes drifting from the eastward, and we were sure that they arose from the island of Volcano, then in eruption, although inquiries from our fellow-travelers as to whether this were so failed to meet a response; either they were stupid or our limited Italian vocabulary was at fault.

It was not until we reached the neighborhood of Castrogiovanni that we had a good view of the noble cone of Etna, distant some forty miles. From this point of view, almost directly west, the grand mountain mass is seen to rise by a very gradual ascent from the regions below, its upper third snow-clad, its steepest slope toward the south. It has undergone little change since the days of Pindar, who nearly twenty-five hundred years ago sang of "the snowy Etna, the pillar of heaven—the nurse of everlasting frost, in whose deep caverns lie concealed the fountains of unapproachable fire—a stream of eddying smoke by day, a bright and ruddy flame by night; and burning rocks rolled down with loud uproar into the sea" (First Pythian Odes). It was the 16th of April, and the season was a late one, but the poplars were leaved out and the vines were much more advanced than in Naples. The green fields were crowded with poppies, wild peas, and other spring flowers in profusion, while farther on in our route, in the outskirts of Catania, the almonds and figs were fully formed on the trees, though still green.

Not stopping at Catania, we took the night steamer for Malta, where we spent a most interesting day, returning by night to Syracuse—a memorable trip one should not miss—and the morning of the 19th found us at Catania.

After lunch we drove through the long, straight Strada Etnea which by a gradual ascent of ten miles ends in Nicolosi, whence tourists start for the ascent of Etna. Passing beyond the city limits, past the lava stream of 1669 on the left, through villages and hamlets surrounded by vineyards and orange trees, we finally not long after sunset drew up at the door of the Hôtel d'Etna in Nicolosi.

It was Good Friday, and as we stepped out of our carriage a festal, torchlit procession issued from a church near by, and passed up a street parallel to ours amid blazing red lights and the explosion of noisy fireworks, toward another church at the upper end of the village. A gamin eagerly accosted us, gesticulating and shouting in our ears, "Jesu Cristo morte!" and appealing to us to follow on with him. Hastily leaving our traveling bags in the hotel, we walked up the street in the gathering gloom and by a short cut entered the church just before the procession reached the door. To the beat of muffled drums and amid glaring, smoking torches entered a priest, followed by a company of men bearing a rude image of the body of Christ stretched on a bier; then poured in a motley crowd of men, women, and children, each wearing a crown of thorns, to be succeeded by a standing image, life-size, of the Virgin dressed in black, and borne by women, also in mourning garb. Not waiting to witness the final ceremonies, we left the church resounding with the music of the brass band, reeking with the lurid smoke of pitch-pine or tar torches, and betook ourselves to the hotel.

It was a jovial company assembled in this wayside inn. Half a dozen German teachers and physicians were making merry over the wine of the country, and cordially invited us to ascend the mountain with them the next day. But we had heard of the new volcano, and had made our plans to visit that. At a late hour, all the rooms having been taken by them, we slept on cots in the dining room.

The morning of the 20th was light and clear, and the unclouded summit of the volcano was like polished alabaster. After an early breakfast the guide and myself, mounted on mules, took the road for Monte Gemellaro. Leaving on our left the old lava stream of 1669, which looked like an unused railway embankment rising about twenty-five feet in height, we soon came to the forked end of the stream, or sciarra, of 1886. To our left towered the double-headed cone of Monte Rosso with its retinue of monticles around its base. The vines were still in full leaf, and the apple trees in blossom; but we soon rode into a cooler zone, where the vines had just begun to leaf out, and they formed the only vegetation except clumps of yellow-flowered broom, with copses of leafless, slender chestnuts. Over the reddish volcanic soil ran nimble lizards—not the beautiful green ones of the regions below, but, chameleonlike in their adaptation to their environment, they were dull reddish brown.

Lunching at the last house, an empty wooden structure, we soon passed beyond the groves of low, slender chestnut trees, above all vegetation, into the desert zone, and, leaving the mules, ascended the crater cone of Monte Gemellaro. The mountain or hill is an ash heap or cinder cone, the loose material likened by M. Émile Chaix to coke or black powdery scoriæ, with lava underneath, and it rises upward of four hundred and fifty feet above the sides of Mount Etna, with a diameter of about six hundred feet. The crater is estimated to be one hundred and twenty-five feet deep, with two fissures at the bottom three or four yards wide. It was named after the distinguished geologist and student of volcanism, the late Prof. Gemellaro, of Catania.

On the way up we passed small fissures, still steaming, and their edges incrusted with deposits of sulphur and arsenic. Such fissures are called solfataras. Small heated masses of rock and clay, still warm, lay scattered about. The structure of the inner walls of the crater is simple, reminding us of the upper edge of the crater of Popocatepetl. Under the bed of ashes the rim of the cone is made up of irregular layers of lava which slope away from the center down the sides. In fact, a crater of this sort is formed by the upthrust of masses of lava; and the repeated showers of stones, bombs, ashes, and lapilli, or coarse gravelly ashes, falling down vertically over the vent, give the regular conical shape to the crater, while the sloping sides of the funnel of the crater are formed by loose ashes rolling down the incline of the irregular vent or fissure at the bottom, which is kept clear by the passage of steam and showers of ashes during the progress of an eruption. The origin of the lava stream which threatened Nicolosi and the other towns below was mostly covered up by the thick layer of ashes. It should be understood that by the term "ashes" is meant the fragments of lava and clay, often with obsidian or volcanic glass, shattered during the more violent throes of the crater; the earthquakes and tremblings being due to the expansion of the steam pent up in the subterranean cavities and reservoirs of lava deep down in the bowels of the earth.

From the accounts published in the scientific journals we gather the facts for the following history of this eruption.

After a series of outbreaks, both from the crater of Etna and at other points below, on the 19th of May the lava began to stream down toward Nicolosi, accompanied by severe earthquakes. The stream divided, and the eruption assumed terrific proportions. The lava advanced over three kilometres in eight hours, steadily pushing on toward the village. On the 20th ten other craters opened. A dispatch stated: "Three of the craters are raging
 
PSM V46 D599 Lava at altarelli etna.jpg
Lava at Altarelli, Etna.
 

fearfully, emitting huge stones to a considerable height, and the roar and tumult are terrible"; meanwhile the central crater on the summit of Etna continued to vomit great columns of steam and ashes. "On Sunday the eruption had greatly diminished, but on Monday morning it broke forth with great violence, and a fresh crater sent out a stream of lava one hundred and fifty metres wide and twenty-three deep, which flowed down at the rate of one hundred and sixty to one hundred and ninety feet an hour toward Nicolosi. On Monday evening the news was very disquieting. The violence of the eruption was then greatly increasing, and Nicolosi seemed doomed to destruction. The noise at a considerable distance is described as resembling a continuous cannonade." On the 19th Prof. Amico recorded ninety-two earthquakes; on the following day, only twenty; but afterward the number rose from twenty-five to thirty, twenty-seven, twenty-five, and finally to fifty-two on the 25th. The eruption reached its height on the 31st of May, and the people were so alarmed that the town was evacuated.

The great lava stream which threatened Nicolosi divided into two, one advancing toward Altarelli and the other descending on the east side of Monte Rosso, and on the od of June stopped within three hundred and seventy metres of the town, parting just behind a structure like that seen in the accompanying picture. The inhabitants affirm that this was in direct answer to the prayers of the clergy, who with their parishioners in solemn procession marched toward the advancing lava when the danger seemed most imminent.

According to Prof. Silvestri, the lava stream of 1886, like that of 1883, flowed from the rent or fissure which was opened in 1875 in the flank of the volcano, and extended in a northeast and southwest direction.

In the September following it was safe to visit the scene, and the Count L. dal Verme estimated that during the eruption Gemellaro ejected about sixty-six million cubic metres of eruptive matter, covering a space of five square kilometres and a half on the flank of the mountain, and approaching within less than half a mile of Nicolosi, situated near the upper limit of the vine. The vineyards were destroyed to the extent of some twenty thousand lire.

In 1890 M. Émile Chaix, of Geneva, ascended Mount Etna, camping out several days on or near its summit. From his bright and interesting account, entitled Une Course à l'Etna, originally contributed to the Journal de Geneve for September, 1890, we quote the following description of the crater of Gemellaro as it appeared the summer succeeding that in which we visited it:

"It still gives out a little sulphurous vapor, and is carpeted with the red, yellow, and white products of the solfatara. But the richest volcanic colors are seen in a solfatara opening in an eminence on the outer and southern side of the volcano. An explosion has laid bare a vertical wall above a mysterious opening, and from this opening different gases have passed out and coated the walls with yellow, white, orange, red, and violet incrustations; these hues are remarkably bright and are enhanced by the setting of ebony which surrounds them.

"The inundations of lava poured out from a series of pits or bocche di fuogo situated in a line below the cone, on the rent from which escaped all that overflowed from Etna in 1886. They are empty monticles, which have the appearance of having been formed of burned coke. They are two, three, and ten metres high, and it is difficult to believe, on looking at them, that they could have given birth to this immense sea of lava which has climbed cones thirty to forty metres high, and which rises with a formidable hill in its middle.

"All this coke which we see is not lava, it is only slag. But this slag, these scoriæ, cover everything up, though it would not have been visible had there not been a deep excavation along the course of the lava stream, next to the pits. This great ravine, nearly a kilometre in length, thirty to fifty metres in width, and from four to twelve metres deep, with vertical walls, enabled us to see the internal structure of a lava stream. It is formed by the superposition of alternating layers of compact lava, a yard thick, with black ashes. In certain places we could count five or six layers, one over the other.

"It appears, then, that the lava stream, itself the result of the eruption, is formed of sheets of lava, which flow out one after the other and pass one above the other, each covering the scoriæ, or rather a part of the scoriæ of the surface of the preceding layer, without filling the interstices. But while layers of ashes or scoriæ only ten to twenty inches thick separate the lava layers, the sides and ends of the lava streams form great heaps of large pieces of loose coke, amid which one can detect the compact lava."

We had left our mules some distance down the mountain, and, while the guide went for them, as we were to return by a different route, I strolled about, enjoying the wondrously beautiful scene far below. A gentle sirocco was blowing, and far down beyond the fields of ashes and cinders a soft, delicate haze hung over the land of the vine and orange, and spread over the deep blue Mediterranean beyond.

We returned to Nicolosi in the hot afternoon sun, passing around by the south of Monte Rosso, skirting the right side of the eastern lava stream, whose entire length was about four miles, and whose rough, broken surface is so well represented by the
 
PSM V46 D602 Etna eruption from 50 metres on may 20 1886.jpg
Eruption, seen at a Distance of Fifty Metres,on the 20th of may, 1886, at 1.30 p. m.
 

photograph here reproduced. The stream ceased flowing when within three hundred and seventy yards of the building nearest the volcano.

It was interesting to observe that the stream did not actually plow up the loose volcanic earth of the vineyards, but simply rolled or flowed over the surface without throwing up the soil. The angle of the sides of the stream is steep and the sides are rough, like frozen foam or congealed slag from a furnace.

The same afternoon we returned to Catania, visited the university, and the next day found us on our way to Taormina, catching from the window of our car fine views of Mount Etna. The accompanying picture will give a faint idea of the wondrously fine view of the volcano as seen from the walls of the interesting ruins of the Greek-Roman theater at Taormina, as well as the town itself, and the flanks of Etna studded with villages and hamlets. It is a view said to be the finest in all Europe, and the claim we will not dispute. Certainly a more magnificent outlook, combining the attractions of a land with a history so rich and varied, of so majestic a volcano, of so fair a sky, and of a sea so beautiful as on that bright sunny April day, never met our gaze.

And then the view of Etna at sunset, from the terrace of the Hôtel Timeo, and again when its cone was lit up by the rising sun, were memorable scenes. The volcano was also kind enough to flame up at night, the light of the glowing but subdued volcanic fires at the bottom of the crater being reflected in the darkness upon the clouds of steam hovering above.

The fires of Etna have subsided, only to be succeeded in that beautiful island by a far more terrible social upheaval; the burden of agrarian wrongs, inflicted by the wealthy landholders, and of the too heavy taxes causing a sudden and widespread volcanic uprising on the part of the downtrodden peasants. Let us hope that by timely concessions and patient readjustments of the relation between landlords and tenants a calm as serene and pervasive as to outward appearance at least reigned over the fair island a few years ago, may speedily return.

 


 
The Rev. Lorimer Fison explained the classificatory system of relationship to the British Association by an examination of the descendants of two brothers and two sisters to the third generation. The Fuegian terms of relationship were taken in the first place as an example of the system. These divide the sexes in any one generation into groups of non-marriageable persons and other groups of marriageable persons. Next, the same relations and their descendants in an Australian tribe were taken, when precisely the same groups appeared as the result of the division of the community into two exogamous intermarrying divisions. It was inferred that wherever the classifactory terms appeared these divisions had existed in the past.