176 Aurora Borealis. 
Those species to which an asterisk is prefixed are new. I have 
been surprised at the great number of these, and others may suppose 
me deceived. But I apprehend that I have fallen short of the num- 
ber of distinct species, rather than exceeded it. Numerous speci 
mens of most of these species are in my collection, which J shall ever 
be happy to exhibit; and for a reasonable return, I am ready to fur- 
nish plaster casts and moulds of my best specimens, colored like the 
rock, with a few of the specimens in the rocks. 
1 have given the above summary, chiefly because I have had fre- 
quent enquiries on the subject from scientific gentlemen, and because 
it may be a Jong time before I shall be prepared to give an account 
in detail. 
3. Observations on the Aurora Borealis of January 25th, 1837; by 
Dewxison Otmstep, Professor of Natural Philosophy and Astron- 
omy in Yale College. 
The 17th of November, 1835, the 22d of April, 1836, and the 
25th of January, 1837, have severally been rendered memorable for 
the occurrence of the Aurora Borealis, in forms and colors more 
magnificent and splendid, than any others witnessed by the present 
generation. The first of these has been already noticed in this 
Journal. (See vol. xxrx. p. 388.) It was distinguished for exbib- 
iting, on a grand scale, nearly all the varieties of the anrora ever 
observed in our climate, including the bank of auroral vapor inthe 
North—the streamers—the arches—the corona formed around the 
magnetic pole of the Dipping Needle—and the undulations or Merry 
Dancers ; while the whole were set off by that peculiar display of 
crimson light, which usually attends the most remarkable displays of 
the aurora. The second, that of April 22d, was distinguished above 
all others which I have witnessed for the auroral waves. They be- 
gan to be observed before the end of twilight, and continued nearly 
all night, following each other with astonishing celerity. My friend 
Mr. Twining and myself, formed each a separate judgment of the 
velocity, and agreed in the opinion that the time occupied by a wave 
in ascending through 45 degrees, was about half a second,—a swifter 
motion than either had ever observed in nature before. ‘The display 
of these undulations from half past 11, and onward, was striking 
beyond conception. Their course was generally upward towards the 
pole of the dipping needle. The evening of the Sth of May, also, 
