520 Dr. Moll on the Aurora Borealis. 



east, whilst Lyra and the Swan descended towards the ho- 

 rizon in the N.W. The air was very calm : after some 

 days of thaw the weather had become frosty. The thermo- 

 meter, during the time of the phenomenon, ranging between 

 26 and 24 Fahr. The little breeze there was blew from 

 the S.E. 



From the S.W. to the N.E. a bright arch of whitish light 

 extended itself through the firmament, its width being about 

 10 or 12. This luminous arch passed through the zenith, a 

 little to the northward of the Pleiades. Its light was of a white 

 colour, and uniform throughout. Shortly after, a second 

 similar arch sprang up to the north side of the first. From 

 the S.W. to the N.E. a column of light arose in an oblique 

 direction ; a similar one formed in the zenith ; these three 

 columns joining together, and thus a double arch of unparal- 

 leled beauty illuminated the heavens, whose continual corus- 

 cations formed a most extraordinary spectacle. To the south 

 of this arch, in that part of the sky where Orion then was, 

 and somewhat lower than y and a of that constellation, and 

 near the Eagle and Dolphin, the firmament was of a dark 

 blue ; and Orion, glittering on this dark ground, shone in 

 beautiful contrast with the vivid light of the luminous arch. 

 The appearance of this arch or luminous belt lasted only a 

 few minutes : it began first to fade in that part of the air 

 whence it arose in the beginning. In the N.W. the air was 

 illuminated as if by the crepuscule of a summer's night. 



Being then in the country, I hastened to an open field, 

 where the view of the horizon in the north was not impeded 

 by buildings. There, in the north, that luminous circular 

 arch, which is so frequently mentioned by writers on the Aurora 

 Borealis, was splendidly visible." I would rather call it a seg- 

 ment of a circle, of which the horizon was the chord. The 

 bright star a Lyra was nearly in the middle of this segment, 

 and it extended as far northward as the tail of Ursa Major. 

 Under this luminous arch the sky was somewhat blacker ; but 

 I did not observe under it that dark part which frequently 

 occurs in descriptions of the Aurora Borealis. From out of this 

 luminous arch, as if from its centre, rays of tremulous white 

 light were incessantly springing up in all directions ; of these 



