C 474 ] 
L XX III . ExtraB of a Letter from Mr . J ohn 
Bartram, of Philadelphia, to Benjamin 
Franklin, LL. D. F. R . S. relating to a 
remarkable Aurora Borealis . 
Philadelphia, Nov. 12, 1 757. 
Read Feb. 25, T TERE is a viiible Aurora borealis; 
at feven o’clock, it was about two 
hours high, to the northward pretty bright, Soon 
after daylight difappeared, it was much more eaft, 
where it was redder, with fome faint ftreamers, whofe 
points reached near forty-five degrees elevation, which 
fioon difappeared, and the light defcended, by degrees, 
under the pole, and by ten o’clock was near extindh 
I fhould be very glad to know, whether (and how) 
it appeared this night with you, which may aflift in 
fome philofophical enquiries. I have not obferved 
any, this fall, before. Yefterday, the weather was cool 
and clear, and the wind pretty firong at north ; and, 
1 believe this the coldefi; evening we have had this fall, 
though this week we had ice as thick as a dollar. 
Extract of the Anfwer to the abcrve Letter. 
London,. Jan. i r, 1758. 
f Thank you for your account of the Aurora. A very 
^ confiderable one appeared here the fame evening, 
being Saturday, November 1,2. I did not fee it, but 
have heard of it from feverai. If it was the lame, that 
you faw, it muff have been very high, or very exten- 
five, as the two places are 1000 leagues afunder. 
LX XIV. 04 - 
