ome to the reader the magnitude and grandeur of the
eruption.

The vibrations or waves generated in August, 1883, at Krakatoa may be
arranged under three heads: (1) Atmospheric Waves; (2) Sound Waves; and
(3) Oceanic Waves; which I will touch upon in the order here stated.

(1) _Atmospheric Waves._--These phenomena have been ably handled by
General Strachey,[8] from a large number of observations extending all
over the globe. From these it has been clearly established that an
atmospheric wave, originating at Krakatoa as a centre, expanded outwards
in a circular form and travelled onwards till it became a great circle
at a distance of 180 degrees from its point of origin, after which it
still advanced, but now gradually contracting to a node at the antipodes
of Krakatoa; that is to say, at a point over the surface of North
America, situated in lat. 6 deg. N. and long. 72 deg. W. (or thereabout). Having
attained this position, the wave was reflected or reproduced, expanding
outwards for 180 degrees and travelling backwards again to Krakatoa,
from which it again started, and returning to its original form again
overspread the globe. This wonderful repetition, due to the spherical
form of the earth, was observed no fewer than seven times, though with
such diminished force as ultimately to be outside the range of
observation by the most sensitive instruments. It is one of the triumphs
of modern scientific appliances that the course of such a wave,
generated in a fluid surrounding a globe, which might be demonstrated on
mathematical principles, has been actually determined by experiments
carried on over so great an area.

(2) _Sound Waves._--If the sound-waves produced at the time of maximum
eruption were not quite as far-reaching as those of the air, they were
certainly sufficiently surprising to be almost incredible, were it not
that they rest, both as regards time and character, upon incontestible
authority. The sound of the eruption, resembling that of the discharge
of artillery, was heard not only over nearly all parts of Sumatra, Java,
and the coast of Borneo opposite the Straits of Sunda, but at places
over two thousand miles distant from the scene of the explosions.
Detailed accounts, collected with great care, are given in the Report of
the Royal Society, from which the following are selected as examples:--

1. At the port of Acheen, at the northern extremity of Sumatra,
distant 1,073 miles, it was suppo