The rapidity with which the effects of the Krakatoa eruption made
themselves evident in all parts of the earth is perhaps the most
remarkable outcome of this extraordinary event. The floating pumice
reached the harbor of St. Paul on the 22nd of March, 1884, after having
made a voyage of some two hundred and sixty days at a rate of
six-tenths of a mile an hour. Immense quantities of pumice of a similar
description, and believed to have been derived from the same source,
reached Tamatave in Madagascar five months later, and no doubt much of
it long continued to float round the world.
SERIES OF ATMOSPHERIC WAVES
Another result of the eruption was the series of atmospheric waves,
caused by the disturbance in the atmosphere, which affected the
barometer over the entire world. The velocity with which these waves
traveled has been variously estimated at from 912.09 feet to 1066.29
feet per second. This speed is, of course, very much inferior to that at
which sound travels through the air. Yet, in three distinct cases, the
noise of the Krakatoa explosions was plainly heard at a distance of at
least 2,200 miles, and in one instance--that recorded from Rodriguez--of
nearly 3,000. The sound travelled to Ceylon, Burmah, Manila, New Guinea
and Western Australia, places, however, within a radius of about 2,000
miles; out Diego Garcia lies outside that area, and Rodriguez a thousand
miles beyond it. Six days subsequent to the explosion, after the
atmospheric waves had traveled four times round the globe, the barometer
was still affected by them.
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