SHORTER ARTICLES AND DISCUSSION. 



87 



SHOETER ARTICLES AND DISCUSSION. 



THE AURORA BORE ALT S OF 

 AUGUST 21. 



To THE Editor: I have been much 

 interested in the account given by Dr. 

 A. F. A. King of the unusual aurora 

 observed by him on the twenty-first of 

 August at York Harbor, Maine (Pop- 

 ular Science Monthly, Vol. LXIII., 

 pp. 563-4), because I also observed it 

 the same evening from a point near 

 Baddeck, Cape Breton Island, Nova 

 Scotia. 



My attention was called to the dis- 

 play about 8:45 p.m., Halifax time 

 (this would be about 7:45 p.m. by east- 

 ern standard time, which I presume 

 is the time used by Dr. King). There 

 was then nothing unusual about the 

 aurora. 



I went out of doors especially for the 

 purpose of ascertaining whether any 

 auroral arch was visible extending 

 from east to west across the zenith; 

 for I observed such a phenomenon here 

 two or three years ago (but without 

 the comet-like appendages described by 

 Dr. King) and have been on the look- 

 out since for its reappearance. Cer- 

 tainly no such arch was visible here at 

 8:45 P.M. on August 21, and the whole 

 display seemed then to be on the wane. 

 Shortly after 9:00 p.m. only a diffused 

 glow remained in the northern sky 

 above a bank of auroral cloud. 



During the course of the night I ob- 

 served the aurora occasionally to see 

 if there was any change, but noticed 

 nothing unusual until 12:45. The 

 arch might have appeared between 

 9:00 p.m. and 12:45 without my no- 

 ticing it, as intervals of at least an 

 hour separated my observations. I can 

 say positively that it did not appear 

 between 12:45 and 2:30 a.m., as I was 

 out of doors continuously watching the 



sky during that time. From 9 : 00 p.m. 

 till after midnight I noticed nothing 

 more than the usual faint glow in the 

 north; but happening to glance out 

 of the window at 12:45 I was startled 

 by the tremendous activity then dis- 

 played. The maximvuu was reached 

 about 1:00 a.m., and by 2:00 A.M. the 

 display was practically over. At 2:30 

 A.M., I returned indoors and made a 

 record of my observations, from which 

 I quote the following extract : 



. . . Looking out about 12:45 (a 

 quarter to one a. m., Saturday) great 

 activity was manifest. The whole 

 northern sky was ablaze, pulsations 

 of light streamed upwards from the 

 horizon as though light phosphor- 

 escent clouds were being blown along 

 by a hurricane. Upon going out I 

 found that faint auroral clouds cov- 

 ered the whole sky even to the south. 

 Faint pulsations of light in the south 

 appeared to be streaming north while 

 the northern streamers streamed 

 south. 



Observing attentively, there seemed 

 to be a luminous streaming upwards 

 from the horizon all around, conver- 

 ging — not at the zenith — but at a point 

 of the sky which I should think would 

 be opposite the sun. I was power- 

 fully impressed by the idea that these 

 were parallel rays directed away from 

 the sun, rendered convergent by per- 

 spective. 



At the point opposite the sun a con- 

 siderable space — roughly circular in 

 outline — seemed to be generally free 

 from luminous cloud effects, except 

 when a suffused glow would come and 

 cover the space — a momentary glow 

 without stream effect. Towards the 

 circular space the stream effects were 

 centrally directed all round, being 

 most marked in the northern and 

 northwestern sky, where the stream 

 effects were vivid — luminous pulsa- 

 tions like light smoke driven by a 

 hurricane. The stream effects were 

 much less marked in the western, 

 southern and eastern sky. Light 

 glows would appear, but only by at- 



