. In effect,
the air over the crater was heaved up to the height of some tens of
thousands of feet, and thence rolled off in great circular waves, such
as may be observed in a pan of milk when a sharp blow pushes the
bottom upward.

The violent stroke delivered to the waters of the sea created a vast
wave, which in the region where it originated rolled upon the shores
with a surf wall fifty or more feet high. In a few minutes about
thirty thousand people were overwhelmed. The wave rolled on beyond its
destructive limits much in the manner of the tide; its influence was
felt in a sharp rise and fall of the waters as far as the Pacific
coast of North America, and was indicated by the tide gauges in the
Atlantic as far north as the coast of Europe.

Owing to the violence of the eruption, Krakatoa poured forth no lava,
but the dust and ashes which ascended into the air--or, in
other words, the finely divided lava which escaped into the
atmosphere--probably amounted in bulk to more than twenty cubic miles.
The coarser part of this material, including much pumice, fell upon
the seas in the vicinity, where, owing to its lightness, it was free
to drift in the marine currents far and wide throughout the oceanic
realm. The finer particles, thrown high into the air, perhaps to the
height of nearly a hundred thousand feet--certainly to the elevation
of more than half this amount--drifted far and wide in the
atmosphere, so that for years the air of all regions was clouded by
it, the sunrise and sunset having a peculiar red glow, which the dust
particles produce by the light which they reflect. In this period, at
all times when the day was clear, the sun appeared to be surrounded by
a dusky halo. In time the greater part of this dust was drawn down by
gravity, some portion of it probably falling on every square foot of
the earth. Since the disappearance of the characteristic phenomena
which it produced in the atmosphere, European observers have noted the
existence of faint clouds lying in the upper part of the air at the
height of a hundred miles or more above the surface. These clouds,
which were at first distinctly visible in the earliest stage of dawn
and in the latest period of the sunset glow, seemed to be in rapid
motion to the eastward, and to be mounting higher above the earth. It
has been not unreasonably supposed that these shining clouds represent
portions of the finest dust from Krakatoa, which has been thrown so
far a