The speculations with which this opinion is accompanied, show the activity of inquiry which was excited among the people adjoining the Mediterranean volcanos.
The early eruptions of Etna are lost in the obscurity of history, and the great mass of the mountain was probably accumulated during the later tertiary periods of geology. The first recorded eruption, in 480 b. c., was followed by others, 427 and 396 b. c.; the intervals averaging 42 years. After 256 years, in which no eruptions are recorded, four more are noticed between 140 and 122 b. c.; average interval 6 years. After 66 years of rest, three other eruptions appear between 56 and 38 b. c.; average interval, 9 years. No eruption is mentioned till 40 a. d.; interval, 78 years; a pause till 251 a. d.; another, still longer, till 812 a. d.; a third to 1169 a. d.; and then, after twelve centuries of rarely interrupted quiet, the mountain became, agitated, and has since continued to manifest its violence, more and more frequently, to the present century. In the twelfth and thirteenth centuries, 3 eruptions; in the fourteenth century, 2; in the fifteenth, 4; in the sixteenth, 3 of unexampled duration; in the seventeenth, 8; in the eighteenth, 14; in the nineteenth, to 1832, 6 eruptions. (See Dr. Daubeny on Volcanos, and Mr. Lyell's Principles of Geology, for details, which are here unnecessary.)
The Lipari Isles present us with yet another variation in the phases of volcanic action and rest. Stromboli is always active, but almost never violent; no cessation having ever been noticed in its operations, which are described by writers antecedent to the Christian era in terms which would be well adapted to its present appearances; while in Lipari, the only indications of volcanic action now existing are the hot springs; and the island of Volcano, in an intermediate state, still emits gaseous exhalations.
Since the first colonisation of Iceland by the Norwegians, the eruptions of the volcanos in that country
