A, OC. Twining—Aurora of Feb. 4th, 1872. 277 
Brackett of Bowdoin College. He obtained two lines in the 
white aurora, one of which was wanting in the red. Prof. Geo. 
F. Barker, of Yale University, has obligingly furnished the fol- 
lowing observations of his own: 
‘The aurora was observed with the spectroscope about 8 
p. M. Three bands were then plainly visible, two of them 
quite sharply defined. The least refrangible of these was the 
well-known red line, first observed by Zéllner. On measure- 
ment, it gave a wave-length of 623 millionths of a millimeter. 
The second in order was the bright line of wave-length 557, as 
given by Angstrém. The third was a nebulous band slightly 
more refrangible. Mr. C. S. Hastings informs me that at seven 
o'clock he was able to detect five lines in the auroral spectrum. 
Beside the three above mentioned, there were two others more 
refrangible. These were, however, too feeble for measurement. 
The white auroral cloud which lay for a time beneath the 
western end of the fiery red tract, and the white streamers 
which shot up from the north, afforded a similar spectrum, but 
without the red line.” 
zenith, and appeared at ‘the Pleiades and in Orion. 
= ee first formed by rays converging to Aldebaran ; and, 
at 74", a luminous cloud-zone, normal to the meridian, moved 
