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Show CHAPTER XIX. History orthe volcanic eruptions in the district round Naples-Early convulsions in the island of Ischia-Numerous cones thrown up there-Epomeo not au habitual volcano-Lake Avernus-The Solfatara-Rcuewal of the eruptions of Vesuvius A.D. 79-Pliny's description of the phenomena-Remarks on his silence respecting the destruction of Herculaneum and Pompeii-Subse. quent history of Vesuvius-Lava discharged in Ischia in 1302-Pause in the eruptions of Vesuvius-Monte Nuovo thrown up-Uniformity of the volcanic operations of Vesuvius and the Phlegrreall Fields in ancient and modern times~ WE shall next present the reader with a sketch of the histol'y of some of the volcanic vents dispersed throughout the great regions before described, and consider attentively the composition and arrangement of their lavas and ejected matter. The only volcanic region known to the ancients, was that of which the Mediterranean forms a part ; and they have transmitted to us very imperfect records of the eruptions in three principal provinces of that region, namely, the district round Naples; that of Sicily and its isles; and that of the Grecian Archipelago. By far the most connected series of records throughout a long period relates to the first of these districts ; and these cannot be too attentively considered, as much historical information is indispensable in order to .enable us to obtain a clear view of the connexion and alternate mode of action of the different vents in a single volcanic group. The Neapolitan volcanos extend from Vesuvius, through the Phlegrrean Fields, to Procida and Ischia, in a somewhat linear arrangement, ranging from the north-east to the south-west, as will be seen in the annexed map. (Pl. 3.) Within the space above limited, the volcanic force is sometimes developed in single eruptions from a considerable number of irregularly scattered points; but a great part of its action has been confined to one principal and habitual vent, Vesuvius or Somma. Before the Christian era, from the remotest periods of which we have any tradition, this principal I.tdlia. of Mismwn. |