glow, but I had observed a remarkably yellow bow in the south,
about 10 deg. above the horizon. In about ten minutes more this arc rose
pretty quickly, extended itself all over the east and up to and beyond
the zenith. The sailors declared, 'Sir, that is the Northern Lights.' I
thought I had never seen Northern Lights in greater splendour. After
five minutes more the-light had faded, though not vanished, in the east
and south, and the finest purple-red rose up in the south-west; one
could imagine one's-self in Fairyland."

All this, and a great deal more, was caused by the dust of Krakatoa!

"But how--how--why?" exclaims an impatient and puzzled reader.

"Ay--there's the rub." Rubbing, by the way, may have had something to do
with it. At all events we are safe to say that whatever there was of
electricity in the matter resulted from friction.

Here is what the men of science say--as far as we can gather and
condense.

The fine dust blown out of Krakatoa was found, under the microscope, to
consist of excessively thin, transparent plates or irregular specks of
pumice--which inconceivably minute fragments were caused by enormous
steam pressure in the interior and the sudden expansion of the masses
blown out into the atmosphere. Of this glassy dust, that which was blown
into the regions beyond the clouds must have been much finer even than
that which was examined. These glass fragments were said by Dr. Fluegel
to contain either innumerable air-bubbles or minute needle-like
crystals, or both. Small though these vesicles were when ejected from
the volcano, they would become still smaller by bursting when they
suddenly reached a much lower pressure of atmosphere at a great height.
Some of them, however, owing to tenacity of material and other causes,
might have failed to burst and would remain floating in the upper air as
perfect microscopic glass balloons. Thus the dust was a mass of
particles of every conceivable shape, and so fine that no watches,
boxes, or instruments were tight enough to exclude from their interior
even that portion of the dust which was heavy enough to remain on earth!

Now, to the unscientific reader it is useless to say more than that the
innumerable and varied positions of these glassy particles, some
transparent, others semi-transparent or opaque, reflecting the sun's
rays in different directions, with a complex modification of colour and
effect resulting from the blueness of the sky, the condit