OF THE AURORA BOREALIS. 13 



a great part of the sky. Although the moon was clown, it was still light enough 

 to see the time of night by the watch." 



Such were the appearances at Yale College; but it seems to me desirable to place 

 on record the phenomena of these highest exhibitions of the aurora borealis, as 

 "they were observed at places remote from each other, in order to see how far they 

 preserved their identity, or how far they were altered by a change of place in the 

 spectator. 



At Mount St. Mary's College, at Emmettsburg, Maryland, this aurora was atten- 

 tively observed by Professor M'Caffrey. 1 The phenomenon is seldom seen at all 

 in that latitude (39°), and especially in any of its more splendid forms. About 7 

 o'clock in the evening of the 22d of April, a large part of the northern heavens 

 was covered with a thin vapor-like appearance, white at the base, of a pale red 

 at the upper edges, and of a deeper hue, red and yellow intermixed, about the 

 middle. It spread through an arc of 00° near the horizon, and extended half way 

 up to the zenith. Before 9 o'clock it had disappeared, leaving nothing but a bank 

 of white auroral vapor, stretching along the northern and northeastern horizon. At 

 fifteen minutes after 10, on looking towards the north, I perceived a few well-defined 

 columns, shooting up a short distance, each of them appearing and vanishing 

 momentarily; yet so that, to a careless observer, they might seem to remain per- 

 manently before the view. Gradually the northern streamers increased, both in 

 number and in length, as new ones sprung up east and west of those obscured origi- 

 nally. Stars could be seen dimly shining through them. The color of the corus- 

 cations was of a bluish white near the base; further up, it was of a brighter and 

 more silvery hue. Those nearest the moon, which was then in her first cpjarter, 

 and gave a strong light, assumed, for a short time, a pale green, then a bright orange 

 color ; and one, which shot up to a great length, became particularly remarkable 

 by its redness. The whole scene was still further enlivened by a beautiful play of 

 crimson light gracefully undulating upwards along the streamers. The long rays 

 continued to shoot up higher and higher, until they all converged to a point on or 

 near the meridian, about midway between Arcturus and Beta Leonis. The right 

 ascension was found to be 19-4° 20', and its declination 18° N. At this point, the 

 streamers, which magnificently decorated the whole northern hemisphere, reddening 

 as they converged, formed a superb oval crown of deep crimson light. This crown, 

 which seemed like a lake of blood, extended about 15° east and west, and 10° or 

 12° in the opposite direction. It had such a preternatural aspect, and, viewed in 

 connection with the accompanying phenomena, one of such overpowering sublimity, 

 as to inspire a profound feeling of religious awe. It lasted from five minutes before 

 11 o'clock until five minutes after. Gradually the redness faded away; the corus- 

 cations, which had lately met and mingled in the color of blood, no longer entirely 

 converged; around the focus was left a blank space of very irregular outline; south 

 of it were seen the broken off extremities of the most northern rays; while all the 

 rays near the convergence had a peculiar brushy appearance. At later periods the 



1 Awcr. Join-. Science, XXXI, 85. 



