After examining the more prominent features of the surface of /Etna, we next proceed to detail the opinion of travellers, respecting its height, constituent tarts, and she mode of its formation. On these subjects, however, we have to regret, that our information is both scanty and inaccurate.
The ancients, if we may judge from the language of their poets, and the allusions made to this mountain in their mythological talcs, regarded /Etna as a mountain of the first magnitude. Pindar speaks of it as the pillar of heaven ; (Pythia. Od. i. v. 36;) and Hvgiuus makes Deu calion and Pyrrha flee to /Etna, as a place of security amidst the wreck of the general deluge. (Hygin. Fab. 153.) In modern times, however, since a knowledge of the earth's surface has been more generally diffused, and the mode of measuring heights better understood, /Etna is known to be a mountain of but secondary importance, and by no means to be compared in point or height with the mountains of the western world, or even with those of the Alps. As the statements of travellers respecting the height of /Ettra (Lifer widely from one another, we shall present our readers with a table of the heights given by different authors, and allow them to judge for themselves, after remarking, that a French wise is a little more than an English lathom, or six feet.
When we reflect, that in every eruption a considerable quantity of new matter is added to its sett lace, we are apt to conclude, that JEtna must be continually increasing in height. There is one circumstance, however, to be ta ken into account, which must limit to a considerable de gree, if not counterbalance entirely, the effect of this ac cumulation If, by frequent eruptions, the size of the mountain is increased externally, its internal parts must sutler a corresponding diminution ; and the effect of this hollowing out of the body or the mountain must evidently he, to occasion a falling in of the summit. That this event frequently occurs, seems more than probable, from the marked difference of configuration which the crater presents at different times. Some have adopted an opi nion, the very opposite of this, and have contende d, that :Etna bears evident marks of decay and diminution. M. I loud, in particular, favours this opinion ; but it is by no means a modern conjecture. (Vide Seneca, 1-../zi•t. 179,
and .Evian, Var. Hie. I. viii. e . xi.) In support of this opinion, it is alleged, that /Etna cannot be seen now at so great a distance as formerly. We are unable to de cide between these contending opinions. That this mountain, in common with others, is subject to continual waste, in consequence of the constant action or rains, mountain torrents, and similar causes, appears undenia ble ; but whether -Etna contains within itself any pecu liar causes of decay, has not yet been clearly made out.
Various and opposite opinions have been entertained by naturalists, respecting the ,formation of !Etna. Some have contended, that it existed as a mountain and vol cano from the creation ; while others maintain, that it ex .hibited no symptoms of a volcano till long alter that pe riod. A third party, perhaps with better reason, regard it as the gradual production of volcanic eruptions.
For the first opinion we are indebted to Beam, who admits, at the same time, that the eruptions ceased for a considerable time, upon the subsiding of the ward s covered the face of the earth. Nor did _Etna again begin to emit her hidden fires, according to the same author, till, by the bursting open of the Straits of Gibraltar and the Bosphorus, the plains of ..Etna were deluged, and thus a new supply of water obtained for maintaining the conflagration.
The second opinion is founded chiefly upon the great heigf.t at which beds of sea-shells have been found on the sides or the mountain. Dolomien states, that he discover:d immense heaps of these shells on the north east flanks of the mountain, at the height of 2000 feet above the level of the sea, and that regular strata of gray clay, filled with marine shells, arc found at a still greater height. Ile further adds, that in scveeal• hat of the mountain, calcareous strata lie under the lava See Kirwan's Paper, Iri811 Transactionii, vol. vi. p. 306. From these lasts it is inferred, that /Etta must base ex isted as a mountain of considerable height, before it was uncovered by the sea, and that, in as far as the calcareous strata and shells lie under the lava, the eruptions must have taken place at a period posterior to their depos: Lion.