726 
APPENDIX. 
over the margin of the ice. As the heavy clouds reached this spot they were gradually con- 
densed the effect of which was precisely similar to that which sometimes occurs about the 
summits of high mountains, against which the clouds are successively driven, without any 
being seen to depart, and without any apparent increase. 
This remarkable disturbance of the equilibrium of the atmosphere being admitted, 
I would here merely suggest whether, under certain dispositions of the atmosphere, elec- 
tricity might not be induced and communicated to the surrounding region, so as to occasion 
the Aurora Borealis, and to account for its appearance in the before-mentioned directions in 
preference to others. 
I am not aware what would be the effect of the meeting of two atmospheres, one influ 
enced by a large body of ice, the other by an e.xtensive continent, such as that of America, 
and particularly when the circumstances might be modified by large frozen lakes. But it 
appears from Captain Franklin’s observations at Great Bear Lake, that the Aurora arose in 
almost all quarters of the horizon, and more frequently illuminated his zenith than the Auroras 
appear to have done either of those at the before-mentioned places. 
Our observations were too limited to justify any remark on the observation of Captain 
Franklin, that the appearance of the Aurora occurs more frequently in the last quarters 
of the moon than in others. 
