564 



APPENDIX. 



[No. III. 



so as to point to 144°. Another beam darted from 257°, and joined the former 

 one. The arch, thus formed, descended gradually against the wind. There 

 was only a slight lateral motion perceptible while it remained across the 

 zenith ; but when it had sunk to about 60° from the horizon, an interior motion 

 rushed from each of the extremities towards the middle, and at the place of 

 contact the greatest commotion was excited, and the prismatic colours were 

 exhibited. The motion of the needle 8' minutes eastward. This arch 

 disappeared at an elevation of 25°. Between Uh. and midnight, sounds 

 were repeatedly heard resembling the hissing of a musket-ball, or the 

 shaking of a thin pliant stick in the air, which were at first supposed 

 to have been occasioned by the motion of the Aurora. Mr. Wentzel, 

 however, who assured us that he had often heard the noise of the Aurora, 

 said these sounds were very dissimilar to that which the Aurora makes, and 

 that he supposed the noise to be occasioned by the cracking of the snow, in 

 consequence of a great decrease in temperature immediately after the two 

 preceding days of mild weather. I was of the same opinion, from the cir- 

 cumstance of a similar noise having been heard after midnight coming from 

 the eastward, in which quarter there was not the least appearance of Aurora, 

 and when only a faint motionless beam was visible to the eastward. This 

 opinion was further confirmed on the following morning, when similar sounds 

 were distinctly heard at the time the sun was shining bright, and there was 

 not any symptom of Aurora. 



12th. At midnight, faint streams from 88° directed towards the zenith. 

 Some patches visible in other parts of the sky. 2i «<: n 



13th. At midnight, a beam shot from 302° across the zenith to 88°. 

 Another extended to the zenith, whose lower extremity bore 290°. A 

 horizontal band from 234° to 257°. The needle since nine moved 1° 25' 

 westward. 



14th. At nine p.m. a faint beam at 99° pointing towards the zenith. At 

 midnight a faint low stream from 76° to 110°. No change in the needle. 



1 5th. At midnight, waving streams from 1 1 0° to 1 44° and from 1 89° to 21 2°, 

 elevated 20° . No change in the needle. 



16th. At 3h. p.m. some clouds appeared about 279°, which bore a strong 

 resemblance to the Aurora, particularly one of the beams, which extended 40' 

 towards the zenith. The needle moved 1 8' westward, between 3h. and 5h. p. m. 



