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On the Aurora Borealis. By John Richardson, M. D., 

 F. R. S., F. L. S., M. W. S. Surgeon and Naturalist to the 

 Arctic Land Expedition.'* 



A HE results of the observations of this phenomenon made du- 

 ring the present expedition, coinciding with the remarks on the 

 same subject, given at much length in the Appendix to my for- 

 mer Narrative, I shall here confine myself to the mention of a 

 few brief deductions from a careful examination of our registers 

 at Bear Lake. 



The observations were made without intermission for six suc- 

 cessive months, in the years 1825-6, and again in 1826-7. 



My opinion, recorded in my former Narrative -|-, that the dif- 

 ferent positions of the Aurora have a considerable influence upon 

 the direction of the magnetic needle, has been repeatedly con- 

 firmed during our residence at Bear Lake. It was also remark- 

 ed, that, from whatever point the flow of light, or, in other words, 

 the motion of the aurora proceeded, if that motion was rapid, 

 the nearest end of the needle was drawn towards that point, 

 almost simultaneously with the commencement of the motion. 



A careful review of the daily registers of the appearance of 

 the aurora has led me to form the following general conclu- 

 sions : 1^^, That brilliant and active corruscations of the aurora 

 borealis cause a deflection of the needle almost invariablv, if 

 they appear through a hazy atmosphere, and if the prismatic 

 colours are exhibited in the beams or arches. When, on the 

 contrary, the atmosphere is clear, and the aurora presents a 

 steady dense light, of a yellow colour, and without motion, the 

 needle is often unaffected by its appearance. 



2J, That the aurora is generally most active when it seems to 

 have emerged from a cloud near the earth. 



3(/, When the aurora is very active, a haziness is very gene- 

 rally perceptible about the corruscations, though the other parts 

 of the sky may be free from haze or cloud. 



• The disturbing effects of the Aurora Borealis on the Magnetic Needle 

 having been denied in some late publications, we now lay before our readers, 

 from Franklin and Richardson's interesting work, observations by Dr Richard- 

 son, which prove the powerful effect of the Polar Lights on the Magnetic 

 Needle. f Appendix, p. 561. 



JULY SEPTEMBER 1838. Q 



