THE AURORA BOREALIS. 713 



On Feb. 18 an Aurora is described as '*of a pale yellow, at 

 " other times white, excepting to the southward, in which direc- 

 " tion a dull red tinge was now and then perceptible." 



The fresh gale which blew at the time from the N.N.E. 

 appeared to have no effect on the Aurora, which streamed directly 

 to windward, and this with great velocity. 



2. Observations of Aurora. By Sir John Franklin. 



Observations were made in Sir John Franklin's Expeditions for 

 magnetic declination and the daily changes of declination, and for 

 the dip. 



Sir John Franklin sums up the results of his experiences of the 

 Aurora in the following general conclusions : — 



1. Brilliant and active coruscations of the Aurora Borealis 

 cause a deflection of the needle almost invariably 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 un- 

 affected by its appearance. 



2. 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 generally 

 perceptible about the coruscations, though the other part of the 

 sky may be free from haze or cloud. 



4. The nearest end of the needle is drawn towards the point 

 from whence the motion of the Aurora proceeds, and that its 

 deflections are greatest when the motion is most rapid ; the 

 effect being the same whether the motion flows along a low arch 

 or one that crosses the zenith. 



5. That a low state of temperature seems favourable for the 

 production of brilliant and active coruscations ; it being seldom 

 that we witnessed any that were much agitated, or that the pris- 

 matic tints were very apparent when the temperature was above 

 zero. 



6. The Aurora was registered at Bear Lake 343 times without 

 any sound having been heard to attend its motions. 



7. The gold-leaf electrometer was never affected by any ap- 

 pearance of the Aurora. 



8. On four occasions the coruscations of the Aurora were seen 

 very distinctly before the daylight had disappeared, and .we often 

 perceived the clouds in the day-time disposed in streams and 

 arches such as the Aurora assumes. 



A brilliant Aurora was seen by Dr. Richardson on April 23, 

 while Lieut. Kendall, who was watching at the time, by agree- 

 ment, at a distance of 20 miles off, did not see any coruscation. 



[In his observations of the two kinds of Aurora, Sir John Frank- 

 lin agrees with M. Angstrom, who finds by the spectroscope that 

 the Aurorse are of two kinds. 



