he unconsciously finished, under
a clearer sky, his interrupted observation. The comet, of which the
silvery radiance contrasted strikingly with the reddish-yellow glare of
the sun's margin it drew near to, was followed "continuously right into
the boiling of the limb"--a circumstance without precedent in cometary
history.[1314] Dr. Elkin, who watched the progress of the event with
another instrument, thought the intrinsic brilliancy of the nucleus
scarcely surpassed by that of the sun's surface. Nevertheless it had no
sooner touched it than it vanished as if annihilated. So sudden was the
disappearance (at 4h. 50m. 58s., Cape mean time), that the comet was at
first believed to have passed _behind_ the sun. But this proved not to
have been the case. The observers at the Cape had witnessed a genuine
transit. Nor could non-visibility be explained by equality of
lustre. For the gradations of light on the sun's disc are amply
sufficient to bring out against the dusky background of the limb any
object matching the brilliancy of the centre; while an object just
equally luminous with the limb must inevitably show dark at the centre.
The only admissible view, then, is that the bulk of the comet was of too
filmy a texture, and its presumably solid nucleus too small, to
intercept any noticeable part of the solar rays--a piece of information
worth remembering.

PLATE III.

[Illustration: The Great Comet of September, 1882.

Photographed at the Royal Observatory, Cape of Good Hope]

On the following morning, the object of this unique observation showed
(in Sir David Gill's words) "an astonishing brilliancy as it rose behind
the mountains on the east of Table Bay, and seemed in no way diminished
in brightness when the sun rose a few minutes afterward. It was only
necessary to shade the eye from direct sunlight with the hand at arm's
length, to see the comet, with its brilliant white nucleus and dense
white, sharply bordered tail of quite half a degree in length."[1315]
All over the world, wherever the sky was clear during that day,
September 18, it was obvious to ordinary vision. Since 1843 nothing had
been seen like it. From Spain, Italy, Algeria, Southern France,
despatches came in announcing the extraordinary appearance. At Cordoba,
in South America, the "blazing star near the sun" was the one topic of
discourse.[1316] Moreover--and this is altogether extraordinary--the
records of its daylight visibility to the naked eye