COINCIDENCE OF SUN SPOTS AND AURORAL DISPLAYS. 19 



phenomena, and we shall be impatient until Prof. C. A. Young makes a report of 

 his observations with the diffraction spectroscope, scarcely daring to think even of 

 a possibility of clouds hanging over Princeton, N. J. We watched the sun the 

 entire day, and when it disappeared in the west, wished the day might be longer, 

 but night brought still other wonders in the heavens. 



At 9 P. M., while viewing Wells' comet, it waned and disappeared. Look- 

 ing out to learn the cause, its o5scuration was found to come from the rising arc 

 of an aurora. The advancing phenomenon presented a yellowish-green arc of a 

 circle, whose altitude was eighteen degrees — nearly half way to Polaris — and 

 whose ends rested on the eastern and western horizon. The thickness of the 

 light was five degrees, clear sky showing the stars in Cassiopeia, being between it 

 and the horizon. ■ The center of the auroral arc did not appear to be on a line 

 below the pole star, so we proceeded to measure its displacement with the decli- 

 nation circle on the telescopic axis. The eastern termination of the arc was only 

 fifteen degrees north of the equator, while the western was twenty-five degrees, 

 the center, therefore, being ten degrees east of the pole of the heavens. For 

 nearly an hour the apparition developed no sign of coming grandeur, but at lo 

 P. M., three pillars of crimson light shot up to an altitude of forty degrees from 

 the western extremity of the arc, a few yellowish streamers ascending in the east. 

 These outbursts seemed to be a preconcerted signal with the celestial pyrotech- 

 nists, for within two minutes the whole arch flashed and trembled, and then, 

 expanded, ascending eight degrees. A halt was made, which lasted, however, 

 not more than one minute, when two flashes in rapid succession were seen 

 throughout the widened arc now twenty degrees broad. A mighty upheaval fol- 

 lowed, the apex of the band at once rose to Polaris, filling the northern heavens 

 with supernal light brilliant enough to read by ; but the terminal points on the 

 horizon, east and west, did not draw nearer the earth's equator. The altitude of 

 the pole at this place is forty-one degrees, and as there was open sky under the 

 band ten degrees wide the belt was thirty degrees broad. The great aurora 

 reserved its forces a few moments and then discharged simultaneously hundreds 

 of columns of scarlet, violet, and light yellow flames, instantly converging at the 

 zenith. 



This display waned only to make way for another more magnificent ; and so 

 the whole night passed, outbursts succeeding in rapid movement. From mid- 

 night to I A. M. the phenomena was at its heighth, the whole northern heavens 

 from the horizon to the equator being striped and banded with varying streamers. 

 Flashes were incessant. A wave of hght would appear in the northern horizon, 

 and instantly rush to the zenith, producing curvature in the straight columns, 

 which at once resumed their original position when the wave subsided, only to be 

 wrought again within a few seconds. The whole northern hemisphere quaked 

 with the rapidity of lightning without cessation during the hour succeeding mid- 

 night, each outburst of energy impelled light-emitting matter directly to the zenith, 

 when it was no longer subject to upheaval, but floated slowly south. Much of 

 this actually descended as far as Scorpio, thirty degrees south of the equator, so 



