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Page:Popular Science Monthly Volume 25.djvu/380

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368
THE POPULAR SCIENCE MONTHLY.

great storm, and about ten miles from this island he encountered an earthquake on the sea, followed by most frightful thunders and cracklings, from which he imagined that an island, or else a piece of the land, had burst up, and shortly thereafter, as they drew a little closer with the ship to the land, and were come near to the mouth of the Sunda Straits, it was evident that the Island of Cracketouw had burst out; and his conjecture was correct, for he and all the ship's company perceived the strong sulphur-atmosphere, also the sea covered with pumice, . . . which they scooped up as curiosities." Save for the observations of passing travelers, by whom the great beauty of its tree-clad slopes, the first verdant spot to meet the eye after weary weeks at sea, has been gratefully described, the volcano, after it died out, has had an uneventful and unrecorded history.

On the 20th of May last year, at half-past ten in the forenoon, the inhabitants of Batavia were astounded by hearing a dull, booming noise, whether proceeding from the air or from below was doubtful, soon followed by the forcible drumming and rattling of all the doors and windows in the place. The commotion was strongest between half-past ten and one o'clock in the day, and between seven and eight in the evening. About midday a curious circumstance was observed—that in some spots in the city no vibrations were perceived, although the surrounding buildings were experiencing them. It was at once concluded that a volcanic eruption of an alarming character had taken place, but for some time it was impossible to localize the direction of the sounds, though the west was the quarter of the compass to which most people assigned them.

A report, issued next day by the director of the observatory in Batavia, stated that, as he had no instruments for recording the intensity and direction of earthquake-shocks, he could certify only that no increase of earth magnetism accompanied the tremblings—the photographs indicating nothing abnormal; and that the quivering was absolutely vertical throughout the periods mentioned above; for a suspended magnet with an exact registering apparatus gave no indications of the slightest horizontal oscillations, but alone of vertical vibrations. This was verified by the observations of one of the philosophical-instrument makers in the town on a pendulum in his shop, where only vertical trillings were observable at a time when the windows and glass doors of the house were rattling, just as if shaken by the hand, in so violent a way that it was difficult to carry on conversation. Nowhere, however, do there seem to have been observed any shocks of a true or undulatory earthquake. From midnight of the 20th throughout the forenoon of the 21st the tremulations continued very distinct. The same morning a thin sprinkling of ashes fell, "whence, is not known," both at Telok-betong and at Semangka, situated in Sumatra at the head of the Lampong and Semangka Bays respectively. At Buitenzorg, thirty miles south of Batavia, the same phenomena