AUROHA BOREALIS 



]AN TIME. 



CAMBRIDGE. 



Profensor Airy. 



N. Lat 52» 13' Long. E. 0° 6' 



8*. 



8. I 

 vertex jS 

 in bread 



8. 1 



Dubhe, 



and ros< 



a i.n. m. 



"• 8. 25. — The aurora appeared in the form of a large bright cloud, bounded on 

 * °,h'"''°^^^'" ^^'^^ ^y ^^^ horizon, and on the upper side by an arch of a small circle 

 60" alt^ differing much from a great circle). The extremities of the arch were in 

 "N. E. and W. N. W. or nearly W. The upper boundary was lower than /S 

 BB Majoris by | X distance from a. Ursae Majoris to /J Urs£e Majoris. Several 

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

 jtly illuminated, whose light ajipeared to originate simply in the illumination 

 jie aurora. 



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

 Svest. 



fe. 58 — The form and brightness of the arch had not sensibly altered ; but a 

 the upR, jjigp^ c\ouA on its face attracted particular attention. The western ex- 

 it vaniS|^jjy jjf jj^jg pijjyj ,^,j,g J, g | Q ^^, ^ jj^gg, jviajo^js, its horizontal length fully three 

 „ '^ i^s the distance from ^ Ursse Majoris to y Ursse Majoris, its vertical breadth 

 ot °\,m '^^" one-fourth of its length, the eastern end being somewhat broader than 

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

 \mers 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 

 . !ront of the black cloud or through it, so as to illuminate it, near its western 



inc ine^^.j^jjjy -^^ ^^.^ nearly vertical lines, corresponding to the course of the 

 connec y^gr^^^ whose upper and lower parts were visible above and below the cloud. 

 ^' tmarkable change in the constitution of the cloud followed immediately ; the 

 ^"' Item half became curdly, the upper edge of its small portions being luminous ; 

 "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 

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



und the dippiiig-veedle to be unaffected by this aurora at Armagh. It was 

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

 a The greatest mtensity of the aurora was in the direction of the magnetic 



n 



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

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

 ai-ick. 



8-V 

 movemt 



rose 

 S. of 

 at their 

 was nea. 

 traces 

 were ve. 



