No. III.] 



LIEUTENANT HOOD ON THE AURORA. 



58.3 



It has, perhaps, been detached by violent motion from a body below the 

 horizon. The second is an arch from north to south. In it the lateral and 

 direct motions are in the same direction. The flashes and beams are, in my 

 opinion, generally inclined in the direction of the dipping needle. Their per- 

 spective must be considered in determining this; for, near the magnetic 

 meridian, they appear perpendicular to the horizon; but when at some distance 

 to the eastward or westward, they decline towards the perpendicular at 

 different angles. 



The coronse, and other wreaths of the Aurora, sometimes approached so 

 near, that the beams appeared under an angle of 10° or 12°. No difference 

 was then distinguishable between them and the flashes before described, 

 except that the time of their existence was shorter. 



The colours, shown by the beams when in rapid motion, were pea-green at 

 the upper extremities, and purple and violet intermixed at the lower. (It 

 will be remembered that these were the three colours which Mr. Morgan 

 produced by introducing an electric spark into an exhausted glass bulb.) 

 On one occasion, the lower colour was orange, which last was, in every 

 instance, the prevailing colour at Cumberland- House. 



On the 8th of March, 1821, at 5h. 30m. p. m., immediately after sunset, 

 an arched Aurora was visible, extending from N.W. to S.E.b. S. This was 

 the earliest period of the day at which we saw it ; for although it might from 

 the shortness of the days in December and January, have been seen at 3 p.m., 

 if present, it seldom appeared before 7 p.m., and was usually most brilliant 

 at midnight. On the 11th of February, the clouds formed a regular arch 

 extending N.N.W. to E. ; and the needle of a compass, fixed in the house, 

 for the purpose of making observations, receded 20° from the magnetic 

 meridian to the westward. I saw these clouds disperse, and afterwards 

 collect in a different form. The disturbance of the compass, is another proof 

 of the presence of the Aurora during the day ; but, on the whole, there is 

 reason to conclude that such is not often the case. On the 13th of November 

 the Aurora was seen, between the clouds and the earth, by Mr. Franklin and 

 Dr. Richardson. On the 13th of March, I saw an Aurora, which was ema- 

 nating in wreaths from the N.W., pass over the lower surface of a stratum of 

 white clouds. The upper edge of the clouds was 80 feet distant from the lower, 

 and its Azimuth, S.35°W. The Aurora passed at the altitude of 70 9 and 



