Aurora at this time were sluggish, but large masses of light were frequently
generated almost instantaneously.
At 7h. 30', a number of arches sprung from the horizon in the N.W.b.N.,
and sweeping across the sky in various directions suddenly curved in, to terminate
in the S.E.b.S. The arches were in general about 6° broad, and their
middles were distant enough from each other to spread on each side of the
zenith t Fromo 9 thh.e t od imstaidnncieg hotf, 5t0h°e. Aurora formed many arches of light, very various
in breadth and density, all having a common origin and termination in the
N.W. and S.E., but crossing the heavens in a variety of directions, so as to
occupy about three-fourths of the space on each side of the zenith.
The middle portions of some of these arches ran horizontally across the sky,
whilst their extremities, making sudden curves, arrived at the common origin
and termination of all the arches, which were seated for the greater part of the
night about 4° above each horizon. At one time the light was arranged in a
series of curves, including each other, and having their convexities turned towards
the north on both sides of the zenith. In short, their arrangement was
continually varying, but the breadth of the arches at all times was greater in
the zenith. Large and diffuse columns of light sometimes shot up at right
angles from the convex side of the arches, and portions of broken arches were
occasionally seen in various parts of the sky, lying obliquely across the general
line of direction. The changes of form were not produced by a quick flashing
motion,, but by the different parts of a new arch appearing simultaneously
but faintly, then gradually brightening up in a manner that could be traced
only by keeping the eye steadfastly fixed on a clear part of the sky, and
watching the evolution of the light there.
At midnight a dear blue sky surrounded the zenith to the distance of about
20°, the rest of the sky had a light-greyish appearance, resembling the light
of the milky-way, many stars shining brightly at the time. In some spots this
diffuse light brightened up for a moment or two, assuming at the same time a
yellowish hue.1 ;
At 12h. 30’, there was an arch in the south about 15° high, and various irregular
masses of light in the north, the rest of the sky being of a deep blue.
At 2h. the sky very clear. At this time the Aurora was very brilliant, and
its motions-so" rapid that it was impossibfe-'-to record them in the order of their
occurrence with any thing like-Accuracy.
At one period the ‘S.W. part-of the sky was occupied by a mass of dense
light, which was connected with3 a 'similar mass hr the: east by a current of light
about 4° broad, moving with extireme-velocity-ffoin W. to E. This* stream of
light bore a stronger resemblance to a cascade of water, thanitotahy thing else
I can liken it topandit in.geheral flowed from the one hMSSbf light tb’the other,
but sometimes'its-eastermextreiriity. curled back in'yMotis'direetiohWformirig
as it were beautiful eddies;- The dark lines or sphSOs; whoS'd insMtaneous
appearance and disappearance'evinced the moti’dh-of the light; lay perpendicular
to its line of direction, or pointing to the north and south.
For an instant, when the motions were most-rapid, the light became very
vivid, and assumed a reddish hue. At this moment, a loudSerash was heard,
similar to what is produced by. a large piece’of ice floating down a river, and
crushing againsta stone.
This noise was not repeated, and as it appeared to come from the river,
would not have been noticed unless for its cotemporaneous!oeefiPrence.with the
brightening of the Aurora. The air at this time was rather favourable for the
transmission of sound, the rapid being distinctly heard.
December 30th, 1820.
Hour. Temp. Wind. A.M. 9 — 53 N.W. Light. Clear. Much mist over the rapid. Low
fog in the valleys*. ' r
Noon, — 52 do. do. Low fog- increasing! -
3 —50 Nearly calm. Hazy in- the- horizon. Rapid moderately
' loud.
9 _ 4 8 W. Moderate. Clear, but a bur round the candle.
Midnight, — 47.5 W. S.W. do. do, -
At 5h. p.m., an arch-formed Aurora extended completely across the sky
from the N.W.b.N.-to the-jS.E.b;E. Tkom-ithe^N.W.* end-of this arch a
pencil of light rose perpendicularly; and terminated at the zenith: Its'hue and
brightness-were equal to that of the milky way,which was distinctly visible at
the time. At 8h. p.m., two columns of light rose perpendicularly from the horizon
in the N.W. and S.E. to the height of 10°. Their summits being connected by