50 RECORD OF AURORAL PHENOMENA. 



were connected by a diffused light. They lay in various directions in the zenith, but towards 

 the horizon they had an appearance of convergency to the N. W. and S. E., and thus formed in 

 the aggregate an arch 30° high in the middle, and tapering towards its extremities. 



At lh. 30m. (27th), the centre part of the above-mentioned arch, or aggregated masses of light, 

 had dilated so as to occupy the whole sky, except a clear blue space of 20° from the northern 

 horizon. The shapes of its component parts had undergone a material alteration, and were now 

 so arranged and blended together as to bear a striking semblance to an immense double curtain 

 with its ends gathered together, in the N. W. by W. and S. E., at about 10° above the horizon, 

 the space beneath being of a clear blue. From the zenith, to carry on the similitude, the folds 

 of the curtain proceeded in several beautiful festoons towards the north and south, and had 

 occasionally a slow motion, as if it were folding and unfolding again and again. The moon at 

 this time shone with a bright light, and illuminated several layers of cloud (cirro-stratus) in the 

 N. E., every other part of the sky being unclouded. 



At 2h. a. m., a large homogeneous sheet of rare light was spread over 20° on each side of the 

 zenith, and near the horizon there were many layers of cirro-stratus, some of them pretty dense, 

 so as to obscure the moon when they passed over its face. The Rapid was quite inaudible at 

 this time."— Ibid., p. 618. 



December 27, 1820. Temp. —45°. 



"At llh. p. m., the sky clear, the moon not yet risen, but many stars visible. A beam of light, 

 about 8° broad, rose from 10° above the horizon in the S. E. by S., and, gradually becoming 

 fainter upwards, disappeared a little south of the zenith. After continuing stationary for some 

 time, it sent forth a beam of light from its southeast end, which extended 11° more to the north- 

 ward, whilst its fainter end was at the same instant prolonged so as to form a complete arch, 

 terminating in the N. W. by W. horizon. A little haze was visible at this time in the southern 

 horizon. 



At midnight, the Aurora formed a somewhat interrupted circle round the sky, about 15° high, 

 which sent down, from its N. W. by W. and S. E. points, several pointed processes which nearly 

 touched the horizon. Some large flexuous streaks, and masses of light traversing the zenith, 

 connected the northern with the southern part of the circle; and there were also a few detached 

 irregular masses of light in other parts of the sky. The best-defined part of the circle was in 

 the N. E. quarter, and here a quick lateral motion to and fro was produced, as if by its separa- 

 tion into perpendicular bars. It was about 8° broad at this place. During the continuance of 

 this phenomenon, many beams of light rose perpendicularly from the upper margin of the circle, 

 but, before they reached the zenith, their extremities were bent from their course so as to make 

 various curves sideways, or even to appear as if rolled up upon themselves. 



When the Aurora had exhibited itself in this form for a considerable space of time, the whole 

 mass of light suddenly appeared in motion, and, sweeping round on each side, was gathered 

 together to the southward of the zenith. Immediately thereafter, a large portion of it was seen 

 in the S. E., assuming an exact resemblance to a curtain suspended in a circular form in the air, 

 and hanging perpendicularly to the earth's surface. The lower edge of this curtain was very 

 luminous, and had a waving motion ; and the illusion was further heightened by the momentary 

 appearance of perpendicular dark lines or breaks in the light, in rapid succession round the 

 circle, exactly as the waving of a curtain would cause the dark shades of its folds to move along 

 it. This beautiful curtain of light was about 40° high, of a pale yellowish color, and sent forth 

 on the one side a process which approached the S. E. by E. point of the horizon, and on the 

 other was connected with a long regular arch, terminating in the N. W. horizon, similarly con- 

 structed, and having the same waving motion with the curtain itself. All this time the sky was 

 perfectly clear, except in the southern quarter, which, to the height of 4° or 5°, was occupied 

 by dark clouds, apparently intermediate between stratus and cin-o-stratus. 



Half an hour after its first appearance, this curtain-formed Aurora was resolved into a number of 

 detached irregular portions, which sometimes increased rapidly in every direction until they met 

 with other masses, either before existing or appearing at the instant, and formed an uniform sheet 

 of light which covered the whole-sky. The formation of this great sheet of light was so rapid, 



