These effects, although natural, have been looked upon as prodigies; and although we see in miniature, by fire, effects nearly similar to those of volcanos, yet there is something in grandeur, of whatever nature it may be, that invariably strikes the imagination and influences the mind, and therefore I am not surprised that some authors have taken them for the vents of a central fire, and ignorant people for the mouths of Hell. Astonishment produces fear, and fear is the mother of superstition. The natives of Iceland imagine the roarings of the volcano are the cries of the damned, and its eruptions the effects of the rage of devils, and the despair of the wretched.
All its effects, however, arise from fire and smoke: veins of sulphur, bitumen, and other inflammable matters, are found in the bowels of mountains, as well as minerals and pyrites, which ferment when exposed to air or humidity, and cause explosions proportionate to the quantity of inflamed matters. This is the just idea of a volcano, and it is easy for a philosopher to imitate the action of these subterranean fires; for by mixing together a quantity of brimstone and iron filings, and burying them in the earth to a certain depth, a small volcano may be produced, whose effects will be exactly similar; for this mixture inflames by fermentation, throws off the earth and stones with which it is covered, and smokes, flames, and explodes like a real volcano.
In Europe are three famous volcanos, Mount Ætna, in Sicily, Mount Hecla, in Iceland, and Mount Vesuvius, near Naples, in Italy. Mount Ætna has burnt from time immemorial, its eruptions are very violent, and the quantity of matter it throws out is so great that after digging 68 feet deep, marble pavements, and the vestiges of an ancient town have been found buried under this thickness of matter, in the same manner as the city of Herculaneum has been covered by the matter thrown out from Vesuvius. New mouths in Ætna were opened in 1650, 1669, and at other times. We see the flame and smoke of this volcano from Malta, about 60 leagues distance; it smokes continually, and there are times when it vomits flames, stones, and matters of every kind with impetuosity. In 1537, there was an eruption of this volcano, which caused an earthquake in Sicily that continued for 12 days, and which overthrew a number of houses and public structures; it ceased by the opening of a new mouth, the lava from which burnt every thing within five leagues of the mountain. The cinders thrown out by the volcano were so abundant, and ejected with so much force, that they were driven as far as Italy; and vessels at some distance from Sicily were incommoded by them. Farelli says the foot of this mountain is 100 leagues in circumference.
This volcano has now two principal mouths, one narrower than the other; smoke comes continually from them, but flames never issue but during the time of eruptions; it is pretended that large stones have been thrown out by them to the distance of 60,000 feet.
In 1683 a violent eruption caused a terrible earthquake in Sicily; it entirely destroyed the town of Catanea, and killed more than 60,000 persons in that town, besides those which were destroyed in the neighbouring towns and villages.
Hecla throws out its fires through the ice and snow of a frozen land; its eruptions are nevertheless as violent as those of Ætna, and other volcanos of southern countries. It throws out cinders, lava, pumice stones, and sometimes boiling water: it is not inhabitable within six leagues of this volcano, and the whole island of Iceland is very abundant in sulphur. The history of the violent eruptions of Hecla are recorded by Dithmar Bleffken.
Mount Vesuvius, according to the historians, did not begin burning till the seventh Consulate of Titus Vespasian and Falvius Domitian; the top being opened, it at first threw out stones and rocks, afterwards fire and lava, which burnt two neighbouring towns, and emitted such thick smoke that it obscured the light of the sun. Pliny the elder, desirous of examining this conflagration nearer, was suffocated by the smoke.[I]
[I] See the Epistle of Pliny, jun. to Tacitus.