See Professor Challis, in the 'Athenaeum', Oct. 31, 1847.] --
Tr.
In the northern latitudes,
p 196
in the immediate vicinity of the magnetic pole, the smoke-like conical
segment appears less dark, and sometimes is not even seen. Where the
horizontal force is the weakest, the middle of the luminous arch deviates
the most from the magnetic meridian.
The luminous arch remains sometimes for hours together flashing and kindling
in ever-varying undulations, before rays and streamers emanate from it, and
shoot up to the zenith. The more intense the discharges of the northern
light, the more bright is the play of colors, through all the varying
gradations from violet and bluish white to green and crimson. Even in
ordinary electricity excited by friction, the sparks are only colored in
cases where the explosion is very violent after great tension. The magnetic
columns of flame rise eithr singly from the luminous arch, blended with
black rays similar to thick smoke, or simultaneously in many opposite points
of the horizon, uniting together to torm a flickering sea of flame, whose
brilliant beauty admits of no adequate description, as the luminous waves
are every moment assuming new and varying forms. The intensity of this
light is at times so great, that Lowenorn (on the 29th of June, 1786)
recognized the coruscation of the polar light n bright sunshine.
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