Page:Popular Science Monthly Volume 67.djvu/562

556 either at the very dawn of Hellenic culture, or during its wane. Secondly, the mainland on either side of the Ægean being free from volcanic action, knowledge of this form of energy was dependent upon the reports of travelers who had visited Etna or Argæus; and our sole reason for supposing that either of these centers was in eruption during the early historical period is based upon their persistent association with Typhon myths. As for the first tremendous convulsion which overwhelmed Thera (Santorin), this happened so long anterior to documentary history that not the least vestige of a tradition has survived. The next fiery outbreak did not occur until about two hundred years before our era, and that of Methona only about a century earlier. Hence, until considerably after the time of Aristotle, the opportunity for studying active volcanoes, either near at hand or in distant regions, was extremely limited.

On the other hand, secondary manifestations of vulcanism were everywhere abundant. The extraordinary prevalence and violence of earthquakes throughout the ancient world, their effect upon the popular mind, and the extent to which even historical events were influenced by them, are facts too well known to require comment. Frequent references in literature to mud volcanoes, solfataras, fumaroles, sulphur springs and allied phenomena reveal a lively curiosity in these matters, and a growing tendency to associate them with volcanic action. Attention early became attracted to the numerous jets of mephitic vapor in western Phrygia, their fancied connection with the infernal regions giving rise to such names as Charonia and Plutonia. The Plutonium of Hierapolis was particularly famous, and so too were the hot springs in various parts of Greece, as at Thermopylæ, and in the north of Eubœa. All these occurrences were associated in the olden time with Heracles in his character of fire-god; and owing to constant succession of earthquake shocks in the Peloponnese, that district became the focus of the worship of Poseidon, the 'earth-shaker.' Gradually a mythological interpretation of these phenomena gave place to a philosophical, crude at first, but elaborated little by little, until finally ideas were developed which have become the heritage of modern science.

It will repay us to trace the development of some of these ideas, though in view of the thoroughness with which this has already been done by Sudhaus in his scientific commentaries on 'Ætna' (Leipzig, 1898), we need not attempt here more than a cursory retrospect. After Thales, who regarded earthquakes as universal disturbances produced