RECORD OF AURORAL PHENOMENA. 19 



the same strange phenomenon at Fort Reliance in November, 1833; at which time there were 

 two dark clouds in opposite directions, and the coruscations brilliantly streaming iu a variety of 

 fantastic figures from behind them. The clouds in detached masses remained for some time 

 assuming various forms, while the Aurora nimbly played round and through them until not the 

 slightest vestige of their presence remained. "We had also frequent opportunities of observing 

 the appearances described by Parry, of long horizontal separations of the Aurora, resembling 

 so many dark parallel streaks lying over it; which was evidently the dark indigo sky only, as the 

 stars were plainly visible. 



I have often observed a gray haze, effectually obscuring the sky, suddenly give way to a mass of 

 light that illumined the whole face of the heavens, as if the atmosphere had instantaneously 

 taken fire, leaving the sky, after it vanished, of a dark blue color, and studded with twinkling 

 stars ; while, on the contrary, the same gray mist has been noticed to take place on the sub- 

 sidence of the Aurora, which was especially the case on the 4th of April, 1834. 



There cannot be a doubt but that this* meteor, from the intensity of its light, dims the stars; and 

 from the following fact it is equally certain, that it obscures the shy also in the form of white 

 clouds during the day, when its luminous appearance is eclipsed by the brightness of the sun. 



A mass of while cloud was observed at 10 a. m. of the 28th of October, precisely similar in shape 

 to an Aurora of the previous evening, and situated in the same place, at which time the sun was 

 shining brightly. Captain Back having placed himself in the shade of a fir-tree, imagined that he 

 saw a faint filmy arch of pale white issuing from it; and after watching more attentively, a pale 

 yellow arch was seen shooting from the mass of cloud to the westward, and extending southerly 

 to S. E. by S. at an angle of 30°. Afterwards several detached radial clouds became visible 

 in the same point, which he more than once thought differed much in brightness. 



Clouds were often observed by us in the daytime, in form and disposition very similar to the Aurora, 

 especially on the 25th of last December [1833], when an arch of streaky and filmy clouds exactly 

 resembling its coruscations extended from east to west across the zenith. Captain Parry was 

 also 'struck with the general resemblance to the form of the Aurora assumed by the clouds, iu 

 the polar regions, at particular seasons.' 



It has always been an interesting question with those who attempt to ascribe this beautiful phe- 

 nomenon to electrical causes, whether the Aurora be attended with any sound or noise; and 

 although many accurate observers have paid particular attention to this subject in various parts 

 of the northern hemisphere, yet the point is far from being settled." — King, II, 90-95. 

 " On no occasion, during two winters, was any sound heard to accompany the motions of the Aurora 

 by either Captain Back or myself. Once or twice I thought a sound was audible, but afterwards 

 ascertained it to be the hissing noise produced by the sudden condensation of my breath into 

 icy particles; and Captain Back several times positively declared he heard a whizzing noise 

 during the rapidity of the motion, until he convinced himself it was the faint murmuring only 

 of Anderson's Fall that had deceived him. 



That a change of color is perceptible in the Aurora, is admitted by almost every author who has 

 described its appearance. I believe it, however, to be of rare occurrence; for, during two 

 winters of five months each, notwithstanding scarcely a night passed away without our observing 

 this beautiful phenomenon, Captain Back and I only witnessed it vary from the flame or straw 

 color eight times; five of which it appeared of a red, and the remaining three respectively of an 

 indigo, lake, and orange color. In about the same lapse of time also it was noticed by Parry 

 to vary three times only, of which it appeared twice of a lilac, and once of a green tint. 



Whether the magnetic needle be affected by the appearance of the Aurora or not, still remains in 

 doubt. There are different opinions upon the subject, and the observations taken by Captain 

 Back and myself have not yet been reduced by the Professor who has undertaken to work them." 

 —King, II, 9G. 

 "In my humble opinion, there are not sufficient facts yet collected to justify us in coming to any 

 conclusions, either as to the effect of the Aurora on the magnetic needle, or as to the most favor- 

 able situation for solving that problem. 



According to Captain Back, who witnessed the Aurora at Forts Franklin and Enterprise, that 

 meteor was not only more brilliant, but the streams of light more rapid, at Fort Reliance than 



