RECORD OF AURORAL PHENOMENA. 43 



As the limbs of these arches approached the horizon, they seemed to be twisted together, and 



terminated on each side in a single, suddenly acuminated point, about seven or eight degrees 



high. These extremities emitted a more dense light than the middle parts of the arches, which 



were rare, and permitted the stars to be seen clear/)/ through them. 

 At 9h. 30m., the moon arose, and the Aurora now formed broken, irregular masses near the southern 



horizon. 

 At lOh. 30m , a depressed arch of the Aurora was formed, its extremities terminating in the 



opposite points of the horizon, or in the N. W. and S. E , and its centre scarcely rising ten 



degrees above the southern horizon. It was more brilliant than the former arch, and completely 



hid the stars. 

 Half an hour after midnight, there were several large masses of light in the eastern and N. E. 



quarters of the sky. The arch had disappeared, but a luminous point remained in the N. W., 



the quarter from whence it originally sprung. 

 About lh. a. m. (10th), several portions of light were arranged so as to form an interrupted arch 



from E. to the N. W. The masses of light before noticed in the E. and N. E. had now united, 



and spread along the horizon to the S. E." — Ibid., p. 603. 



December 10, 1820. Temp. —43°. 



" At half past six p. m., an arch of the Aurora appeared having an elevation of 30° and a direction 

 from II". A. W. to S. S. E. It was irregularly elevated and depressed in various parts, and its 

 breadth, which was in general about 6°, occasionally expanded so as to occupy thrice that space. 



These dilatations were. effected with a slow motion, and were partial, seldom including more than 

 10° or 15° of the arch at a time. The centre of the dilating part was more brightly illuminated 

 than the other parts of the arch. The return of the arch to its former dimensions was equally 

 gradual with its dilatation. 



The arch was occasionally divided into five parallel beams, which, having a direction nearly from 

 north to south, traversed it obliquely. 



These beams had a quick lateral motion, and were sometimes gathered into masses that receded so 

 far from each other as to break the arch into several portions, which had pointed extremities, 

 arising from the obliquity of the beams which composed them. 



The length of the beams was sometimes considerably increased by their northern extremities 

 shooting up whilst their lower ends remained stationary. These appearances were but of 

 momentary duration, the beams rapidly reuniting to form a homogeneous arch. 



After the Aurora had continued for about half an hour to display a succession of the above forms, 

 the arch totally disappeared, and a horizontal mass of light was observed in the southern quarter 

 of the sky, having its face longitudinally barred by several thin strata of clouds. 



At lOh. 30m., there were various irregular masses of light scattered over the sky, but most 

 luminous in the north. 



The Aurora had appeared early in the night in the west; afterwards, its most luminous parts were 

 collected in the south. About nine, it shone most brightly in the eastern quarter of the sky, 

 and now, as we have just mentioned, its principal seat was in the north." — Ibid., p. G04. 



N. B. — 1. The beams had a quick lateral motion. 



2. Aurora early in the night in the u-est; then its most luminous parts were collected in 

 the south; at nine, it shone most brightly in the eastern quarter; at lOh. 30m., its 

 principal seat was in the north. 



December 11, 1820. Temp. —31°. 



"At 5h. p. m., several broad arches of rare light appeared, extending from A 7 ". W. to S. E. At 6h. 

 they disappeared, no change in the weather having occurred in the interim, the sky remaining 

 clear, with a bright moon. 

 At 9h. an arch was formed in the east, broad, irregular, and rather faint. Its extremities bore 



X. and S. E., and were spirally twisted near the horizon. 

 At lOh. 30m , there was an arch in the southern quarter of the sky, 40° high. Its extremities had 



