VOL. LIX.j PHILOSOPHICAL TRANSACTIONS. 66l 



It is probable, that some hitherto unknown property of electricity is con- 

 cerned in this phenomenon. This power has undoubtedly a great share in the 

 descent of rain, which hardly ever happens, if the air and electrical apparatus be 

 sufficiently dry, without manifest signs of electricity in the air. Hence it is, 

 that in Lima, where there is no rain, they never have any lightning or thunder; 

 and that, as M. Tournefort was assured, it never rains in the Levant but in 

 winter, and that this is the only season in which any thunder is heard. If this 

 appearance therefore could be accounted for, it would probably help us to some 

 more satisfactory causes of the suspension of the clouds, and of the descent 

 of rain, 



; cd iyH'.hii! 

 XLVIII. Of an Eclipse of the Moon, observed at Hawhhill, near Edinburgh. 



By James Lind, M. D. p. 363. 



Eclipse of the moon, Dec. 13, 17^9, at Hawkhill. 



Sidereal time. Mean time. 



ist contact of darkness Q*" 59™ 19^ = iQ^ 30™ 51* 



Moon's limb broken 10 7 50 = 16 39 21 



Copernicus, central 10 30 32 = 17 1 59 



Middle of eclipse 11 32 37 = 18 3 54 



Moon's limb completed 12 57 24 = 19 28 27 



2d contact of darkness 12 59 24 = 19 30 27 



End of smoky appearance 13 5 25 = I9 38 27 



Since Dr. L. wrote last, he had taken another meridian observation for the 

 latitude, and made it 55° 57' 30" n. 



Remarks by the Astronomer Royal. — ^The beginning of the eclipse was ob- 

 served at the Royal Observatory at lO*" 20™ 29', and the bisection of Copernicus 

 at lO*" 43™ 23' sidereal time; which, compared with the correspondent observa- 

 tions above, give 12™ 39' and 12"" 51' of time, for the difference of meridians 

 of Hawkhill and Greenwich. Nevil Mashelyne. 



XL IX. Of Two Aurorce Boreales observed at Oxford. By the Rev. John 



Swinlon, B. D., F. R. S. p. 367. 



Mr. S. casting his eye towards the northern part of the hemisphere, on 

 Sunday, Feb. 26, 1769, about 8'' 30™ p. m. discovered there a pretty bright 

 aurora borealis of the common kind. For a short time, there was a very quick 

 succession of lucid columns, and corruscations ; which seemed smaller than they 

 usually are in such meteors, that appear often enough here. But what princi- 

 pally engaged his attention, was the gradual approach of the aurora towards the 

 south, insomuch that though it was at first most apparently an aurora borealis, 



