h. i 



8. 



8. 



vertex ji 

 in bread 

 8. 1 

 Dubhe, 

 and rosi 



AURORA BOREALIS 



GAN TIME. 



CAMBRIDGE. 



Profensor Airy. 

 N. Lat. 52» 13' Long. E. O" 6' 



8 3£' *"' 

 shootim ■ ^'^ — "^^^ ^^^°^^ appeared in the form of a large bright cloud, bounded on 

 northeri "'^'' ^^^^ ^^ ^^^ horizon, and on the upper side by an arch of a small circle 

 fin« alt ^'^'^'■'"S '""'^'i '"'"<"" a great circle). The extremities of the arch were in 



60" alt 



N. E. and W. N. W. or nearly W. The upper boundary was lower than jS 

 ae Majoris by | x distance from a Ursaa Majoris to /J Ursa Majoris. Several 

 111 black clouds were scattered over the aurora-cloud, and above it were several 

 ^ly illuminated, whose light appeared to originate simply in the illumination 



e aurora. 



at theirj 

 was ne; 

 traces < 

 were ve 

 inclinec 

 connect. 



J8. 35— No change, except that the whole appeared to have moved a little to 

 "• ^vest. 



tliruDn^' ^^ — '^^^ *°™ ^""^ brightness of the arch had not sensibly altered ; but a 

 it vanis^ ^'^*^'' *^'°"'^ °" '^® ^^^^ attracted particular attention. The western ex- 

 rose hii^''^ °^ '^'^ '^'""'^ """^ ^^^°'" y ^'^® Majoris, its horizontal length fully three 

 S ofttf'^'^*'^'^'^"" from /3 UrssE Majoris to y Ursee Majoris, its vertical breadth 

 .1 than one-fourth of its length, the eastern end being somewhat broader than 

 ^ western. The aurora-cloud suddenly formed itself into streamers, (or 

 iimers were formed in front of it) some perhaps 30° or 40° high, but lasting in 

 state only for an instant, and two streamers of sensible breadth shot up either 

 jont of the black cloud or through it, so as to illuminate it, near its western 

 uccC^'^'"*'^ in two nearly vertical lines, corresponding to the course of the 

 9^ ^■"^■■>*' "hose upper and lower parts were visible above and below the cloud. 

 10* Z'"'*'''*^'^'^ change in the constitution of the cloud followed immediately ; the 

 • "Item half became curdly, the upper edge of its smaU portions being luminous ; 

 J western half began to disappear ; at 9. 15. no trace of the cloud discoverable. 

 ' 9. 10 — A shooting star from E. to W. very nearly through i Ursa Majoris. 

 I light of the aurora-cloud gradually diminished ; the part which remained 

 ;est was a little E. of N. where some light was still visible at 10. 30. 



lund the dipping-needle to be unaffected by this aurora at Armagh. It was 

 s^ the dark segment was formed at about 12^ h. ; the phenomena ceased 

 aj The greatest intensity of the aurora was in the direction of the magnetic 



m 



B 18th, at 8. 34. a low arch was seen there passing below the feet of U. 

 ^(in the middle) above the horizon ; at 8. 50. the lower edge of the lower 



irfick. 



