48 RECORD OF AURORAL PHENOMENA. 



south. The arch at first exhibited a vermicular motion from east to west, then split into parallel 

 beams, possessing, as usual, a rapid lateral motion; and, in a short time, the Aurora in every 

 part of the sky began to move with such velocity, and to assume such a variety of forms, as to 

 defy description. The central arch more than once exhibited two distinct currents, or motions 

 of its parts, flowing from one end to the other in opposite directions at the same instant; and 

 at one time all the detached parts of the Aurora appeared to collect together to form a beautiful 

 circle or corona, which surrounded the zenith at the distance of 45°, and in which the rapid lateral 

 motion of the beams was very apparent, having a direction from north, round by the south, 

 west and east. The beams, in this case, were apparently perpendicular to the earth's surface in 

 every part of the luminous ring which they formed. In a half arch, which rose immediately 

 afterwards from the northern horizon to the zenith, the extremities of the beams were directed 

 from east to west, and the ranges of beams which formed, in rapid succession, masses of light 

 of various shapes in every part of the sky, had no certain direction. The general color of the 

 Aurora was a pale yellowish-gray ; but when the beams moved with a rapidity that could scarcely 

 be followed with the eye, they emitted a pale but bright red light, slightly tiuged with purple 

 or violet. These beams sometimes lengthened and shortened themselves with extreme rapidity, 

 and the prolonged extremities emitted a light equally brilliant, and of the same hue, with the 

 rest of the beam. In about fifteen minutes, the whole of these beautiful phenomena vanished, 

 leaving behind only a few faint masses of light. The moon was still surrounded by a slight 

 bur, and the wind had changed to the west. 

 At midnight, the southern quarter of the sky was occupied by a broad horizontal mass of light. 

 At lh., there was no appearance of the Aurora whatever. Sky cloudless, but rather hazy; 

 minute crystals of snow falling. During the evening, the wind was very variable, but light." — 

 Ibid., p. 614. 



December 22, 1820.. Temp. —43°. 



"At 4h. 30m. p. m., dark and rather cloudy. A faint mass of the Aurora in the E. S. E., about 

 20° high. 



At nine o'clock p. m., the sky being of a pretty deep-blue color, except in the S. E., where there was 

 a mass of white clouds near the horizon, the Aurora appeared in the form of an arch of yellowish- 

 gray light, about 70° broad in the centre, where it reached from the zenith to within 29° of the 

 southern horizon. Its limbs were spirally twisted and tapered, touching the horizon in the S. E. 

 by S. and N. W. by W. The light of this arch was arranged in longitudinal bands, having 

 different densities, and varying in length from 20° to 80°. These long portions of light occa- 

 sionally receded laterally from each other, and then formed a series of arches or parts of arches, 

 the upper ones including those beneath them. Whilst the arches were thus separated, some of 

 them exhibited a waving lateral motion, the others remaining stationary, and sometimes, one 

 end of an arch moving more than the other, it was carried obliquely across the general line of 

 direction of the parts of the large arch. The arches approached each other by an irregular, 

 slow, lateral motion, occurring simultaneously in the different arcs, and again formed a con- 

 tinuous body of light, varying in density in different parts. 



At llh., a beam of light rose from the southern horizon to the height of 45°, where it terminated, 

 that end then bearing N. W. by N. It was about 10° broad, and gradually attenuated from its 

 centre outwards. 



At llh. 30m., there was a long luminous bank in the south, nearly of equal dimensions throughout. 

 Its centre was slightly elevated, and about 40° high. Its extremities faded imperceptibly away 

 in the S. S. E. and western parts of the sky. It was about 6° broad, and emitted a greenish- 

 yellow light. The sky near its extremities was dark, and completely hid the stars. Five or 

 six degrees below this nearly horizontal mass, a smaller but similar one appeared for a short 

 time. Neither continued above two or three minutes, and they exhibited no quick motions, 

 but merely brightened a little, undergoing at the same time a slight dilatation. They appeared, 

 however, and disappeared at intervals until 2Jh. a. in. (23d), when a haziness overspread the 

 sky. "—Ibid., p. 010. 



