Laacher See

" 122 " 24. Extinct Craters in the Jaulân " 130 " 25. Mount Shasta " 139 " 26. Forms of Volcanic Tuff-Cones, Auckland " 148 " 27. "The White Rocks," Portrush, Co. Antrim " 157 " 28. Section across the Volcanic Plateau of Antrim " 159 " 29. Section at Templepatrick " 161 " 30. Cliff above the Giant's Causeway " 163 " 31. The Giant's Causeway, Co. Antrim " 165 " 32. "The Chimneys," North Coast of Antrim " 166 " 33. Section at Alt na Searmoin, Mull " 175 " 34. View of the Scuir of Eigg from the East " 181 Map of Volcanic Band of the Moluccas " 200 " 35. Map of the Krakatoa Group of Islands " 203 " 36. Section from Verlaten Island through Krakatoa " 204 Fig. 37. Isoseismals of the Charleston Earthquake Page 223 " 38. Photograph of the Moon's Surface " 241 " 39. Portion of the Moon's Surface " 243 PLATES. I. & II. Magnified Sections of Vesuvian Lavas. III. & IV. Magnified Sections of Volcanic Rocks.

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Volcanoes: Past and Present.

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PART I.

INTRODUCTION.

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CHAPTER I.

HISTORIC NOTICES OF VOLCANIC ACTION.

There are no manifestations of the forces of Nature more calculated to inspire us with feelings of awe and admiration than volcanic eruptions preceded or accompanied, as they generally are, by earthquake shocks. Few agents have been so destructive in their effects; and to the real dangers which follow such terrestrial convulsions are to be added the feelings of uncertainty and revulsion which arise from the fact that the earth upon which we tread, and which we have been accustomed to regard as the emblem of stability, may become at any moment the agent of our destruction. It is, therefore, not surprising that the ancient Greeks, who, as well as the Romans, were close observers of the phenomena of Nature, should have investigated the causes of terrestrial disturbances, and should have come to some conclusions upon them in accordance with the light they possessed. These terrible forces presented to the Greeks, who clothed all the operations of Nature in poetic imagery and deified her forces, their poetical and mystical side; and as there was a deity for every natural force, so there was one for earthquakes and volcanoes. Vulcan, the deformed son of Juno (whose name bears so strange a resemblance to that of "the first artificer in iron" of the Bible, Tubal Cain), is condemned to pass his days under Mount Etna, fabricating the thunderbolts of Jove, and arms for the gods and great heroes of antiquity.

The Pythagoreans appear to have held the doctrine of a central fire (μέσον πῦρ) as the source of volcanic phenomena; and in the Dialogues of Plato allusion is made to a subterranean reservoir of lava, which, according to Simplicius, was in accordance with the doctrine of the Pythagoreans which Plato