Disturbance of the Needle during an Aurora. 119 



west, a complete view of the north western portion, and from the top 

 of my dwelling a tolerable field of view to the north. 



At ten minutes past ten the light of the aurora was as brilliant as at 

 the observation at ten o'clock, the brightest portion extending from 

 20^ to 30^ east of the north point, and the diffused light extend- 

 ing at least 60° from the north towards the west. The upper limit 

 of the light was a waving line declining rapidly in the eastern por- 

 tion, and more slowly in the western part. The substratum of black 

 clouds (cumulo stratus) from behind which the aurora appeared to 

 emerge, and which at ten o'clock extended about eight degrees above 

 the horizon, had risen, and a number of small and very black clouds 

 (cumulus) appeared, intercepting portions of the light. At fifty min- 

 utes past ten, the waving line, forming the top of the nebulous light, 

 had become more regular, its elevation not being, in any part, more 

 than 12° above the horizon, its extent being about 100°. The floating 

 hill-clouds (cumulus) had elongated, diminishing in number, but in- 

 creasing in size. I supposed the phenomenon to be passing off, when 

 just before twelve o'clock commenced the most brilliant display which 

 I remember to have seen. At twelve, the nebulous light had risen 

 in an irregular line nearly 40° above the horizon ; and to the west- 

 ward of north, apparently emerging from behind the luminous cloud, 

 were diverging beams of light, more brilliant than the body of the au- 

 rora, varying constantly in the degree of brightness, and in extent. 

 The appearance at within a few minutes of the time mentioned, I 

 have attempted to represent in the annexed figure, (Fig. 2, plate I.) 

 When I speak of the beams being diverging, 1 mean, of course, that 

 they appeared to diverge ; the point of divergence was below the hori- 

 zon, but its position I could not, at any time, determine to my satis- 

 faction. The phenomenon resembled, inform, the beams sometimes 

 seen in the eastern part of the sky when the sun is setting, and which 

 appear to proceed from a point below the eastern horizon, except that 

 these beams were of a beautiful light, apparently streaming from be- 

 hind a cloud of light. There was at this time no dark cloud visible 

 to the north. 



Of the beams which I have endeavored to describe, those nearest 

 the north faded first, and new ones sprang up further to the west of 

 north, much exceeding in apparent breadth those seen near the north. 

 Small black cumulus and cumulo stratus were scattered through the 

 cloud of light. At eight minutes past twelve, four beams were visi- 

 ble, the broadest being furthest to the west ; the last beam died away 



