Volcanic eruptions are awfully terrific, and sometimes extensively destructive. The violent eruption of Vesuvius, in 1767, is reckoned the 27th since that which destroyed the cities of Herculaneum and Pompeii, in the reign of the Emperor Titus; and this eruption of 1767, has been succeeded by several others. Of the eruptions of Ætna, Mr. Oldenburg has given a historical account in the Philosophical Transactions, No. xlviii. p. 967. A very great eruption of this mountain was in the year 1669. The progress of the lava, or fiery deluge, was at the rate of a furlong a day. It advanced into the sea 600 yards, and was then a mile in breadth. It had destroyed, in forty days, the habitations of 27,000 persons; and of 20,000 inhabitants of the city of Catanea, only 3,000 escaped. This inundation of liquid fire, in its progress, met with a lake four miles in compass, and not only filled it up, although it was four fathoms deep, but raised it into a mountain. Borelli, an ingenious Neapolitan, has calculated, that the matter discharged at this eruption was sufficient to fill a space of 93,838,750 cubic spaces. The lava which ran from it is fourteen miles in length, and, in many parts, six in breadth. There have been no such eruptions since, although there have been signs of many, more terrible, that preceded it.[35] The principal volcanos in Europe are Mount Vesuvius, near Naples, in Italy; Mount Ætna, in Sicily; Mount Hecla, in Iceland; and Stromboli, the most northern of the Lipari islands, north of Sicily. Of all the volcanos recorded in history, Stromboli seems to be the only one that burns incessantly. Ætna and Vesuvius are sometimes many months, and even years, without the least emission of fire; but this is ever at work, and, for ages past, has been considered as the light-house of the Mediterranean Sea. It is very probable, that Mount Vesuvius and Mount Ætna form but different portions of _one_ chain of mountains that passes under the sea, and the isle of Lipari; for whenever one of the volcanos has a great eruption, it is observed that the other, and the volcano in the isle of Lipari, throw out more flames than ordinary. This remark was made by Huet, Bishop of Avranches, in France, a celebrated philosophical, historical, and commercial writer. The force of volcanos is supposed to be the greatest of any thing yet known in nature. In the great eruption of Vesuvius, in 1779, a stream of lava, of an immense magnitude, is said to have been projected to the height of at least 10,000 feet above the top of the mountain. [The present state of chemical science, and the geological discoveries of the last ten or fifteen years, seem to discountenance the theory, that volcanic action, and earthquakes result from _sulphur_, _iron_, and _water_, as Mr. Lemery’s experiment seems to indicate.