326 Mr. J. Rand Capron on the Auroral 



west quarter of the horizon. The exact direction, however, is 

 (doubtless for the same reasons which affected the time of ap- 

 pearance, time of flight, and size) but rarely given. In some 

 instances qualifying words are used, such as (in my own obser- 

 vation) "nearly." In others, degrees of deviation from the 

 cardinal points are given ; and generally there seems a ten- 

 dency on the part of observers situated northwards to place the 

 rising and setting points southwards, and the reverse with the 

 southern observers; but beyond this the deviation from the E. 

 and W. points respectively, according to the observer's station, 

 is not very regularly indicated. The observers have not stated 

 whether astronomical or magnetic points are recorded; pro- 

 bably in most cases the former are intended. The only 

 instances where precise figures are given are those of the 

 observations at Utrecht and Zonnemaire, in which, after sta- 

 ting the direction of flight in a general way as E. to W. and 

 N. of E. to S. W., both observers agree in fixing upon E. 20° N. 

 to W. 20° S. as the horizontal direction. Having thus ascer- 

 tained as nearly as we may the hour of appearance, time and 

 direction of flight, and size of the beam, its particulars may be 

 summed up as follows: — 



(a) Character, auroral. 



{b) Time of appearance, a little after 6 p.m. 



(c) Time of flight, about 75 seconds. 



(d) Apparent approximate length and breadth, 27° x 3J°. 



(e) Direction of flight, magnetic E. to W. 



We will now gather from the observers some idea of its 

 general appearance to the eye. The descriptions recorded are 

 sometimes peculiar in expression ; but all fairly represent a 

 similar form. Among them are : — " spindle-shaped," " forme 

 defuseau," "torpedo or weaver's- shuttle," "cigar-ship," "len- 

 ticular," and a " comet's-tail," while one observer not inaptly 

 compares it to the well-known fusiform nebula in Andromeda. 

 For descriptive colour, those selected seem to be "white," 

 "pearly white," "greenish white," and "yellow white," it 

 being somewhat significant of the beam's specific character 

 that the last two combined will represent the locus of the prin- 

 cipal aurora line indicated in Prof. Piazzi Smyth's beautiful 

 colour plate in ' Madeira Spectroscopic ' by the tint " citron." 

 The quality of the light is somewhat variously described in 

 such terms as " glowing,' " shining," and " phosphorescent ;" 

 and one observer (obs. 20) compared it to an electric glow in 

 vacuo ; and certainly to me it was not at all unlike the glow 

 of a carbon Greissler tube. The Utrecht observer (obs. 24) 

 speaks of it as " feathery;" but to me and most other English 

 observers the edges were fairly well defined. I thought, how- 



