[18] If we take the maximum velocity to be 12 feet per second, and the period to be one second, the amplitude would be about 11½ inches.
[19] Vol. ii., p. 299. The punctuation of the original is not followed in the above extract.
[20] British Association Report, 1851, pp. 272-320.
CHAPTER III.[ToC]
THE ISCHIAN EARTHQUAKES OF MARCH 4TH, 1881, AND JULY 28TH, 1883.
Separated from Italy by a distance of not more than six miles, Ischia and the intermediate island of Procida strictly form part of the Phlegræan Fields, the well-known volcanic district to the north of Naples. Ischia, the larger of the two islands, is six miles long from east to west, and five miles from north to south, and contains an area of twenty-six square miles. In 1881, the total population was 22,170, that of Casamicciola, the largest town, being 3,963.