5th. The atmosphere very dense and hazy. The needle had been disturbed
in the night, and shewed this morning a considerable change of position. At
midnight Aurora gleamed through the haze in two arches, the extremities 54°
and 234°, and they passed the zenith. One of them turned towards the north,
and the other towards the south. The needle moved to die eastward, as on
February 3d and January 14th, when the Aurora appeared in a similar position.
6th. At midnight, Aurora was perceived across the zenith 279° and 99°,
gleaming through a very dense atmosphere, and when snow was falling; two
stars only were visible. Motion of the needle since 9h. p. m. 28' westward.
8th. A faint stream at 99° towards the zenith.
9th. At 9h. p.m. a beam at 290°; at llh., a broad arch traversed the zenith
from 290° to 110°, which remained until 45' after midnight, and then disappeared
at bearing 99°. Motion of the needle westward.
10. At midnight, an arch resembling a horse-shoe, the extremities of
which bore 99° and 76°; from each of these points streams were projected
across the zenith towards 290°, but they did not reach the opposite horizon.
They were of a faint greyish-yellow colour. The stars shone brilliantly through
the columns of light; moon very bright. The needle was not the least affected.
I have observed that the needle is usually most disturbed by the appearance
of the Aurora in dense hazy weather.
11th. At three p. m. a cloud extended in an arch from 99° to 279°, elevated
30°, which bore a strong resemblance to the Aurora, particularly at the end at
279°, from whence some beams were projected towards the zenith. The needle
was not affected.
12th. At 8h, 30' p.m. faint curved streams in the zenith. At 9h. an arch
from 99° to 2799, exactly similar in shape to the cloud seen yesterday. The
colour resembled the halo round the moon. The needle was not affected. At
llh. 40' the coruscations occupied a considerable portion of the northern part of
the sky lying in parallel arches from 76° to 279°. The centre one was brilliant,
and the motion, resembling a volume of smoke, passed from the former bearing
towards the latter. Some arches appeared in the zenith lying 65° and 245°,
and flashes darted with instantaneous motion from these towards the point to
which their extremities were directed. The needle betrayed a slight motion
eastward. At 12h. a broad band of light from 302° to 54°, elevated 20°.
February I3lh, the atmosphere was so dense this night, that the stars were
completely obscured, and the edges of the moon could only be faintly traced
through the haze. At nine p.m., there was not any appearance of the
Aurora, and the needle rested at 348° 3(7, its usual position at this hour,
when undisturbed by the Aurora. At 11° 30', faint streams of light gleamed
through a large portion of the heavens, both in the zenith and near the horizon,
and immediately afterwards brilliant coruscations burst forth of the
most agitated kind. At llh. 40', a horizontal stream extended from 279°
to 31°, and the anterior motion, similar to rolling smoke, passed from the first
point to the latter. The needle was now drawn 3° 30' to the eastward, or
as far as 345° 00'. At llh. 50', there appeared another stream of irregular
shape, which proceeded from 279° in a line nearly parallel to the horizon, until it
curled round at 9°, or near the direction of the magnetic meridian. The interior
motion flashed along this stream with the utmost rapidity. .The needle moved
now to 343° 50', or 4° 40' eastward of its first position. And during the appearance
of this coruscation, I perceived the needle to oscillate between 343
50V and 344° 40'; and it may be remarked this was the only occasion on which
a vibratory motion was observed. Qn the disappearance of this display, brilliant
semicircular curves were presented in the same quarter, ornamented With
all the prismatic colours. At llh. 55m., the needle had receded westward as
far as 347° 00'. The important fact of the existence of the Aurora, at a less
elevation than that of dense clouds, was evinced on two or three occasions this
night, and particularly at llh. 50m., when a brilliant mass of light, variegated
with the prismatic colours, passed between an uniform steady dense eloud and
the earth; and, in its progress, completely concealed that portion of the cloud
which the stream of light covered, until the coruscation had passed over it,
when the cloud appeared as before.
The observations of this evening seem to corroborate the remark which I had
previously made—that the direction in which the needle moves, appears to
depend on the position in which the streams of Aurora are placed, and the
quantity of the effect upon its proximity to, or distance from, the earth. When
the extremities of arches lay near-the bearings of 234° and 54°, the needle
moved eastward; and when near the bearings 324° and 144°, or 279° and 99°,
the motion of the needle was westward. Both of these facts were shewn to