soared? No doubt a straw will show which way the wind blows,
but there are no straws up there. There was nothing to render the winds
perceptible until Krakatoa came to our aid. Krakatoa drove into those
winds prodigious quantities of dust. Hundreds of cubic miles of air were
thus deprived of that invisibility which they had hitherto maintained.

"With eyes full of astonishment men watched those vast volumes of
Krakatoa dust on a tremendous journey. Of course, every one knows the
so-called trade-winds on our earth's surface, which blow steadily in
fixed directions, and which are of such service to the mariner. But
there is yet another constant wind. It was first disclosed by Krakatoa.
Before the occurrence of that eruption, no one had the slightest
suspicion that far up aloft, twenty miles over our heads, a mighty
tempest is incessantly hurrying, with a speed much greater than that of
the awful hurricane which once laid so large a part of Calcutta on the
ground and slew so many of its inhabitants. Fortunately for humanity,
this new trade-wind does not come within less than twenty miles of the
earth's surface. We are thus preserved from the fearful destruction that
its unintermittent blasts would produce, blasts against which no tree
could stand and which would, in ten minutes, do as much damage to a city
as would the most violent earthquake. When this great wind had become
charged with the dust of Krakatoa, then, for the first, and, I may add,
for the only time, it stood revealed to human vision. Then it was seen
that this wind circled round the earth in the vicinity of the equator,
and completed its circuit in about thirteen days.

A VAST CLOUD Of DUST

"The dust manufactured by the supreme convulsion was whirled round
the earth in the mighty atmospheric current into which the volcano
discharged it. As the dust-cloud was swept along by this incomparable
hurricane it showed its presence in the most glorious manner by decking
the sun and the moon in hues of unaccustomed splendor and beauty. The
blue color in the sky under ordinary circumstances is due to particles
in the air, and when the ordinary motes of the sunbeam were reinforced
by the introduction of the myriads of motes produced by Krakatoa even
the sun itself sometimes showed a blue tint. Thus the progress of the
great dust-cloud was traced out by the extraordinary sky effects it
produced, and from the progress of the dust-cloud we inferred the
movements of