No. Ill] LIEUTENANT HOOD ON THE AURORA. 595 



atmosphere with clouds, so that the Aurora was not visible. Perhaps, after 

 all, the Aurora of the 27th of April was nearer to the earth than any other 

 which we saw. 



On the 11th of March, at lOh. p. m., a body of Aurora rose N.N.W., and 

 after a mass of it had passed to E. b.S., the remainder broke away, in 

 portions consisting each of several beams, which crossed about 40° of the sky 

 with great rapidity. We repeatedly heard a hissing noise, like that of a 

 musket-bullet passing through the air, and which seemed to proceed from the 

 Aurora ; but Mr. Wentzel assured us that this noise was occasioned by severe 

 cold, succeeding mild weather, and acting upon the surface of the snow, 

 previously melted in the sun's rays. The temperature of the air was then 



35°, and on the two preceding days, it had been above zero. The 

 next morning, it was — 42°, and we frequently heard a similar noise. Mr. 

 Hearne's description of the noise of the Aurora agrees exactly with Mr 

 Wentzel's, and with that of every other person who has heard it. It would 

 be an absurd degree of scepticism to doubt the fact any longer ; for our 

 observations have rather increased than diminished the probability of it. 



We were informed by the natives, that the Aurora indicated, by peculiar 

 appearances, the state of the atmosphere which was to follow on the ensuing 

 day. For instance, when it is bright, and the motion rapid, it will be 

 succeeded by a strong wind ; but when attenuated and expanded over the 

 sky, by mild and cloudy weather. A careful examination of the meteorological 

 journal does not furnish sufficient foundation for these conclusions. But, 

 although the influence of the Aurora upon the weather has been deemed 

 insignificant, it is by no means improbable that the latter considerably affects 

 the former. To suppose that a luminous body, floating in the air, and some- 

 times situated near the clouds, is within the bounds of the ordinary atmo. 

 spherical changes, and may announce those changes by assuming a form which 

 must be in some measure determined by the circumambient pressure, is not, 

 I should think, inconsistent with any philosophical principles. If we had 

 not, unfortunately, lost the only instrument calculated for the purpose, we 

 might at least have ascertained what relation the weight of the air bears to 

 this interesting meteor. 



In the month of January, one of Kater's azimuth compasses was fixed on a 

 shelf within the house, near a parchment window, which admitted the air 



4 F 



