Extract of a Letter from Mr. John Bartram, of Philadelphia, to Benjamin Franklin, LL. D. F. R. S. Relating to a Remarkable Aurora Borealis

LXXIII. Extract of a Letter from Mr. John Bartram, of Philadelphia, to Benjamin Franklin, LL.D. F.R.S. relating to a remarkable Aurora Borealis. Philadelphia, Nov. 12, 1757. Read Feb. 25, 1762. Here is a visible Aurora borealis; at seven o'clock, it was about two hours high, to the northward pretty bright, Soon after daylight disappeared, it was much more east, where it was redder, with some faint streamers, whose points reached near forty-five degrees elevation, which soon disappeared, and the light descended, by degrees, under the pole, and by ten o'clock was near extinct. I should be very glad to know, whether (and how) it appeared this night with you, which may assist in some philosophical enquiries. I have not observed any, this fall, before. Yesterday, the weather was cool and clear, and the wind pretty strong at north; and, I believe this the coldest evening we have had this fall; though this week we had ice as thick as a dollar. Extract of the Answer to the above Letter. London, Jan. 11, 1758: I thank you for your account of the Aurora. A very considerable one appeared here the same evening, being Saturday, November 12. I did not see it, but have heard of it from several. If it was the same, that you saw, it must have been very high, or very extensive, as the two places are 1000 leagues asunder. LXXIV. Obi-