6l4 PHILOSOPHICAL TRANSACTIONS. [aNNO I762. 



nomena, he cannot determine ; to him it has seemed most natural that the rays 

 Hinder the foregoing circumstances, first become obstructed, and many of them 

 wholly absorbed, the rest proceeding with a retarded motion, are thereby first 

 more reflected, and then less refracted through the humours of the eye; and 

 lastly, the image on the retina becomes hereby enlarged. In other words, cer- 

 tain accidents making the rays more divergent than they otherwise would be, at 

 their entrance into the eye, seem to Mr. D. to be the cause of these and other 

 like appearances. 



LXXIIl. Extract of a Letter from Mr. John Bar tram, of Philadelphia, to 

 Benjamin Franklin, LL. D., F. R. S., relating to a Remarkable Aurora Bo- 

 realis. Dated Philadelphia, Nov. 12, 1757- p. 474. 



Here is a visible aurora borealis; at 7 o'clock it was about 2 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 

 45 degrees elevation, which soon disappeared, and the light descended by degrees 

 under the pole, and by 10 o'clock was nearly extinct. 



Extract of the Answer to the above Letter. Dated London, Jan. 11, 1758. 

 I thank you for your account of the Aurora. A very considerable one ap- 

 peared here the same evening, being Saturday, Nov. 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. 



'JLXXIV. Observations on Noxious Animals in England. By the Rev. Richard 

 ! Forster, M. A., Rector of Shefford in Bucks, p. 475. 



^ ^'^is paper proves what is now perfectly well known, viz, that the slow- worm 

 is an innoxious animal, and its bite attended with no ill consequences. 



The author relates 2 cases, both of which happened under his own inspection, 

 and which were productive of no other mischief than that of momentary alarm. 



LXXV. On the Extraordinary Agitation of the Sea* at Barbadoes, March 3 1 , 

 1761 ; and an Epidemical Disorder in that Island. By Mr. A. Mason, p. 477- 

 There was here a very extraordinary motion of the sea, March 3 1 , not unlike 

 that remarked here on the dreadful day of calamity which happened at Lisbon ; 

 with this difference, the last was not so sudden as the former in the flux and 

 reflux : which sufliciently shows, that the shock must have been greater that oc- 

 casioned it, as most likely they proceeded from the same cause, viz. that of an 

 -•.If! ''n 



* See another account of this agitation at p. 6OI, of this volume. 



