Lewis.] V04 [April 21, 



swift, tremulous waves of light. At the same time a mass of fine red 

 color appeared in the north-west, and Hashed alternately bright and dark, 

 as though a red cloud illuminated by heat lightning. This mass of red 

 color moved rapidly westward and was preceded by remarkable flashes of 

 red. At 11.25 the aurora had risen nearly to the zenith, and was of great 

 brilliancy. Numerous narrow streamers, covering the entire northern 

 half of the sky, were flashing bright and dark with great rapidity, while 

 fine crimson patches appeared independently in several portions of the sky. 



At 11.30, or a few minutes later, the whole aurora from all sides moved 

 with a bound toward the zenith. Streamers shot up from north, east and 

 west with rapid, tremulous motions, reaching higher and higher with each 

 pulsation, until, after apparently several ineffectual attempts, they all con- 

 verged at a point nearly on the meridian nineteen degrees south of the 

 zenith to form a corona of great beauty. Tliis corona, which at first was 

 unsteady and continually broken into detached segments, had become, at 

 11.40 P. M., a constant feature. Streamers now radiated from it in every 

 direction, south as well as north. The whole sky seemed in motion ex- 

 cept this one point. Rapid waves traveled along the narrow streamers from 

 the horizon nearly up to the corona, while great nebulous masses and broad 

 bands of crimson light flashed out in different portions of the sky. These 

 masses of red light, particularly noticeable in the north-west, had no defi- 

 nite form, and showed no undulating pulsations like those of the thread- 

 like streamers, but either hung steadily in the sky for some minutes, or 

 else were illuminated with flashes like lightning. The impression was 

 given that these red portions of the aurora were distinct phenomena, dis- 

 connected from the greenish-white streamers, and, perhaps, at a greater 

 distance from the earth. 



The centre of the corona appeared to be some 12 degrees east of Arc- 

 turus. At 11.50, the centre of the corona was estimated to have the posi- 

 tion R. A. 204°, Dec. 21= 30'. 



At midnight the corona, a perfect star of light, had become wonderfully 

 beautiful. The brilliancy of the whole aurora was concentrated at this 

 point, the horizon being comparatively dark. Remarkable coruscations 

 of light surrounded the corona, and these were often curved so as to ap- 

 proach in form a hyperbola of large eccentricity, whose transverse a.xis 

 passed through the centre of the corona. The streamers between the 

 corona and the northern horizon now united into remarkable concentric 

 hyperbolic curves of great brilliancy, whose vertices were stationary near 

 the corona, and Avhose tremulous arms, made up of many streamers, 

 reached to the northern horizon. This form recalled the drawings made 

 of the coma of certain comets, and suggests interesting analogies. 



Still more closely did these curves of light resemble those assumed by 

 iron filings in the vicinity of a magnet, and it is probable that they were 

 identical. 



The centre of the corona was now at R. A. 207° Dec. 21° 30'. 



