A Popular History of Astronomy During the Nineteenth Century: Fourth EditionClerke, Agnes M. (Agnes Mary)
History
A Popular History of Astronomy During the Nineteenth Century: Fourth Edition
Clerke, Agnes M. (Agnes Mary)
Astronomy -- History -- 19th century
"But the most remarkable circumstance attending the phenomenon was the
appearance of _three large protuberances_ apparently emanating from the
circumference of the moon, but evidently forming a portion of the
corona. They had the appearance of mountains of a prodigious elevation;
their colour was red, tinged with lilac or purple; perhaps the colour of
the peach-blossom would more nearly represent it. They somewhat
resembled the snowy tops of the Alpine mountains when coloured by the
rising or setting sun. They resembled the Alpine mountains also in
another respect, inasmuch as their light was perfectly steady, and had
none of that flickering or sparkling motion so visible in other parts of
the corona. All the three projections were of the same roseate cast of
colour, and very different from the brilliant vivid white light that
formed the corona; but they differed from each other in magnitude....
The whole of these three protuberances were visible even to the last
moment of total obscuration; at least, I never lost sight of them when
looking in that direction; and when the first ray of light was admitted
from the sun, they vanished, with the corona, altogether, and daylight
was instantaneously restored."[154]
Notwithstanding unfavourable weather, the "red flames" were perceived
with little less clearness and no less amazement from the Superga than
at Pavia, and were even discerned by Mr. Airy with the naked eye. "Their
form" (the Astronomer Royal wrote) "was nearly that of saw-teeth in the
position proper for a circular saw turned round in the same direction in
which the hands of a watch turn.... Their colour was a full lake-red,
and their brilliancy greater than that of any other part of the
ring."[155]
The height of these extraordinary objects was estimated by Arago at two
minutes of arc, representing, at the sun's distance, an actual elevation
of 54,000 miles. When carefully watched, the rose-flush of their
illumination was perceived to fade through violet to white as the light
returned, the same changes in a reversed order having accompanied their
first appearance. Their forms, however, during about three minutes of
visibility, showed no change, although of so apparently unstable a
character as to suggest to Arago "mountains on the point of crumbling
into ruins" through topheaviness.[156]
Public-domain text, read in full here on John Shaqi.
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