Etna (Lat. AEtna, probably from Gr. to burn), a volcano of Sicily, called by the inhabitants of the island Mongibello, from a combination of the Italian monte with the Saracenic jebel, also meaning mountain. It rises from the E. coast of the island, midway between its N. and S. extremities. The port of Catania is on the prolongation of its S. foot, and, as its history shows, is by no means beyond the reach of its devastating lava currents. North of the mountain is the Val di Demone, watered by the river Alcantara; and 30 m. S. of it is the N. margin of the Val di Noto, in which the waters of the Giaretta find their way toward the coast amid the ancient scoria) of the great volcano. The country between these rivers is occupied by the mountain with its various ridges, volcanic cones, and deep depressions, which cover altogether an area of about 87 m. in circumference; yet the lava has spread far beyond these limits. In the midst is the apex of the great conical mass, the highest summit, as ascertained by Sir J. Herschel in 1824, being 10,872 1/2 ft., or 10,835 according to a measurement adopted by Petermann in his latest maps.
The latitude of the point is 37° 43' 31" N., the longitude 15° E. The cone, at the summit of which is the great crater, is in the midst of a comparatively level region, 9 m. in circumference, the highest point being 1,100 ft. below the principal apex. Around the mountain, at its base, is a fertile and delightful region known as the regione culta. Near Catania this is 11 m. broad, till one reaches in ascending the regione silvosa, or woody district; but on the N. side the wood skirts the mountain to within half a mile of its foot. This lowest belt is the region of cultivation; towns and villages are clustered upon it; and in the rich soil of the decomposed lava and tufa are flourishing plantations of olives, vines, grain, fruits, and aromatic herbs. Though in the frequent eruptions some of these are often swept away, or buried beneath the flow of lava, the attractions of the delicious climate, and of a soil so productive, overcome the fears of a people familiar with the danger, and render them comparatively indifferent to the annoyances of the sharp volcanic dust. The woody region encircles the mountain in a belt 6 or 7 m. in width; but the extensive forests are much broken in upon by the ravages of the lava.
Here are fine groves of chestnut and cork trees, and in the higher portions pines of great magnitude abound, together with oak, beech, poplar, and hawthorn of immense size. The most famous of these trees is the gigantic chestnut tree seen from Aci Reale, which is, however, described by Capt. Smyth as a cluster of what appeared to be seven trees growing together, the largest of which measured 38 ft. in circumference, and the whole 163 ft. This region affords pasturage for many herds and flocks. Its elevation gives it a cooler and more agreeable temperature than that of the lowest belt. At the height of 5,362 ft. is the Goats' cavern or grotto, frequented by these animals in bad weather, and formerly a resting place for travellers, until the shelter known as the English house was built immediately under the cone, at the height of 9,592 ft., at the expense of some British officers who were stationed in Sicily. The upper edge of the woody region is estimated at about 6,000 ft. above the sea. Beyond it is the cold and desolate zone of the mountain called the regione deserta. Its surface spreads out in broad tracts, compared to plains, which are rough and black with the naked lava and scoriae, or white with drifts of snow, which perpetually cover the highest summits.
These also collect in the crevices and grottoes of this portion of the mountain, and furnish supplies of ice to the inhabitants of the island, and of Malta and the neighboring region of Italy. In 1828, when the whole country was parched with the excessive heat, a quarry of perennial ice was opened under a stratum of lava, so situated that this must have flowed in a melted state at some distant period over the snow, which, as suggested by Sir Charles Lyell, was no doubt protected from the action of the heat by a previous covering of fine dust and scoriae. The great crater is on a mountain of stones and ashes, which rises about 1,100 ft. above its base in this snowy tract. The diameter of its mouth is estimated by different travellers at from 1/4 to 1/2 m., and the depth from 600 to 800 ft. Sulphurous smoke and rumbling noises issue from it continually. The view from this summit at sunrise is magnificent. The mountain itself, lying directly beneath the eye of the observer, which can penetrate into the inferior cones upon its flanks, presents the most original feature of the landscape. The cones, however, are best seen from the lower borders of the desert region.
Of these secondary volcanoes Lyell enumerates 80 which are of considerable dimensions, and one of these, called Monte Minardo, near Bronte, is 700 ft. high; and the double hill Monti Rossi, near Nicolosi, formed in 1669, is 450 ft. high, with a base 2 m. in circumference. They are produced by lateral eruptions in the desert region or in the wooded belt below. In the latter their height is reduced by the flow of lava from higher sources, which gathers around, and in some instances buries them and even pours into their craters. - The earliest recorded eruption of Etna is one mentioned by Diodorus Siculus, which caused the Sicani to desert its vicinity and move further to the south. No date is given, but it appears to have happened before the Trojan war. The next are three eruptions referred to by Thucydides, of which, according to his narrative, one was in 475 B. C, one in 425, and one at an earlier time not clearly specified. These, added to the later recorded eruptions to the present time, make about 70 in all. The most important are those of 1169, 1669, 1755, 1787, 1792, 1852, and 1868. An earthquake in March, 1669, destroyed all the houses in the village Of Nicolosi, 10 m. from Catania, near the lower margin of the wooded district.
Streams of lava not many days afterward broke forth from chasms which opened in different parts of the mountain. These destroyed as many as 14 villages. From a gulf that formed near Nicolosi, sand and scoria) were projected that produced in the course of three or four months the double cone Monti Rossi. A fissure 12 m. long was formed, which emitted a most vivid light, and extended to within a mile of the summit of Etna. Afterward five other parallel fissures opened, which gave forth smoke and loud bellowing noises. These fissures, which were without doubt partially filled with lava, afford an illustration of the manner in which the porphyritic dikes are formed, which are seen cutting the lavas, and projecting in the form of walls from the precipitous sides of the deep valleys of the mountain; and also of the origin of the trap dikes of older formations. By the flow of the lava among the deep caverns within the mountain, its vaulted foundations were melted away, and the crest, rent with numerous fissures, settled into the vacant spaces. To protect the city of Catania, its walls next the mountain had been raised to the height of 60 ft.; but the lava rose steadily till it overtopped the rampart, and poured a cascade of liquid fire into the midst of the houses.
Long afterward, when excavated by the prince of Biscari, the solid lava was brought to view, its layers curling over the wall, as if just petrified in their flow. Its rate of progress varied greatly with the consistency of the melted matter and the slope of the surface. The greater part of the 15 m. of its flow to the sea was accomplished in 20 days, but the last 2 m. were only at the rate of 22 ft. an hour. Its surface exposed to the air was a crust of solid rock; through the side walls streams of the fluid lava often burst out, and by excavating into the great current at suitable places the flow might be diverted in new directions. Attempts to do this by some of the inhabitants of Catania, to protect their town, were opposed with arms by the people of Paterno, as the new current threatened to bring destruction upon their habitations. In some places hills of older lava were melted into the flowing stream. In others the cooling matter taking an arched form protected objects on the surface by enclosing them in grottoes of lava. Thus were preserved many valued articles from one of the churches of Mompiliere, afterward obtained by excavating 35 ft. into the solid lava.
This lava current was so hot at Catania eight years after it entered the town, that it was impossible to hold the hand in some of the crevices. The great lava current as it flowed into the sea had spread over a width of 600 yards, and its depth was estimated at 40 ft. The water was thrown into violent commotion. Sounds louder and more terrific than peals of thunder were constantly sent forth, and the light of the sun was darkened by the clouds of vapor. The fish were destroyed along the coast, and many months passed before the water became again clear and transparent. - The eruption of 1755 is remarkable for a great inundation caused by the flow of two streams of lava upon a vast collection of snow. For 8 m. down the flanks of the mountain the torrent poured, sweeping on the loose scoriae and blocks of lava, which were deposited in the plains below. The inhabitants believed that the water was discharged from the crater itself, and the stories of its saltness and of the marine shells contained in it are still found in the popular accounts of this eruption.
Mount Etna from Catania.