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VOYAGE FOR THE DISCOVERY 
1820. E.b.N., and extending to 60° of altitude in the N.N.E., so as evidently not 
to form a part of the western arch. Captain Sabine afterwards observed 
the whole phenomenon to alter its position, the leg of the eastern arch 
shifting considerably more to the southward. In the evening the Aurora 
Borealis was seen, forming a confused and irregular arch of white light, con- 
tinually varying in brightness, about 8° high in the centre, and extending 
from S.b.E., round by the west, to N.N.W. From the upper part of this arch, 
coruscations occasionally shot upwards, and a few streamers now and then 
burst forth also from the horizon in the S.S.E. ; these latter went nearly up 
to the zenith, while the rest were more faint, and did not reach so high. 
I am confident, that Aldebaran and the Pleiades were very sensibly dimmed 
by the most vivid of the coruscations, which appeared, in this respect, 
not to differ from any thin vapour or cloud floating in the atmosphere. 
The gold leaf of the electrometer, as well as the magnetic needle suspended 
in the observatory, was carefully attended to, but neither of them suf- 
fered any sensible disturbance. 
Wed. 9. Early on the following morning, the wind increased from the N.N.W., and 
continued to blow a strong breeze from that quarter, with a heavy snow-drift, 
Thur. 10. till towards noon, on the 10th. At a quarter past six P.M., on that day, the 
Aurora began to appear in the south and S.W., in detached, and not very 
brilliant pencils of rays darting upwards from near the horizon. Soon after, 
an arch of the usual broken and irregular kind appeared in the western 
quarter of the heavens, extending from N.W. to south, and being from 5° 
to 8° high in the centre. From the upper part of the arch proceeded a few 
faint coruscations reaching to no great height. At a quarter before seven, 
a second and better-defined arch crossed over from S.E. to N.W.b.N., 
passing on the northern side of the zenith, from which it was distant from 
10° to 15° in the centre. This arch was very narrow, and seemed to be 
formed of two parts, each shooting with great rapidity from those parts where 
the legs stood, and joining in the centre. In a short time this second arch en- 
tirely disappeared, and the first became less brilliant. The phenomenon 
was then for some minutes confined to some bright pencils of rays in the 
south and S.S.E., which were generally parallel to each other, but sometimes 
also diverged at an angle of about 15°. At a quarter past seven, two long 
and narrow streams of light crossed over at 35° to 40° of altitude, on the 
western side of the zenith, from the N.W.b.N., and south points of the 
horizon ; their upper ends did not quite meet in the centre, so as to complete 
