118 AURORA BOREALIS, 



larly in the spring and autumn, and when it is considered that the 

 Aurora cannot be visible unless the atmosphere is clear on both 

 sides of the pole in the direction of the sun, it will appear probable 

 that it does not often happen ; and in summer of course the Aurora 

 cannot be seen in latitudes where the sun is then above the horizon 

 below the pole, but I have often observed an appearance in the sky 

 resembling the pencil rays of an aurora, with the exception that 

 the illumination of the clouds was overpowered by the light of the 

 day ; and as the sun was then always in opposition to the north- 

 ward, I can have no doubt but that this phenomenon was an aurora, 

 caused by the rays of the sun reflected from the circumpolar moun- 

 tains of ice to the clouds: and I may add, that this appearance has 

 been noticed by several navigators of the Polar Regions. 



The noise of the Aurora, described by some as resembling a silken 

 flag exposed to a fresh breeze, and by others as that of a rushing 

 noise like fireworks playing off*, was never heard or observed, on any 

 of the recent Arctic voyages, and it may be concluded that such 

 a noise does not take place in these regions : if, however, it is insisted 

 upon to be the fact in more southern latitudes, it may probably 

 be occasioned by the combination of the Aurora with electric 

 matter, which is not found in the north. 



Since this paper was read at that excellent institution, the 

 British Association for the advancement of Science, I have had 

 the satisfaction of learning that several of its most distinguished 

 members had made observations corroborative of my theory ; 

 among which I may mention those of W. L. AVharton, Esq., of 

 Drybuni, Durham, who has kindly transmitted to me the copy 



