Meter ological Obscrvalions . 



26i 



and the aurora, conlinued through the night, Tlie day ioUowuig was 

 j-ainy, attended with vivid lightning and heavy thunder. 



The next appearance of the aurora borealis which I shall notice, 

 occured on the evening of the 9th of March. There was nothing 

 unusual in the appearance of 

 the aurora on that evening ex- 

 cept the form of the arch, and 

 that was such as I never before 

 witnessed, nor am I able to ex- 

 plain the cause. There was 

 no moon at the time — the sky 

 was clear — and the stars bril- 

 liant. The wind had blown 

 from the south during the day, 

 but the evening was unusually 

 calm. The thermometer stood 

 at 26°. Early on that evening, 

 streams of light shot up in the 

 north as usual, but were princi- 

 pally confined near the horizon. 

 At half past 8 o'clock a bright 

 arch was formed which rose to 

 the height of about 40°. It 

 was well defined, and extend- 

 ed to the horizon on the east 

 and west. This arch exhibited 

 the appearance of segments or 

 sections of circles, of different 

 diameters, all of which were 

 perfectly united. This appear- 

 ance continued about fifteen 

 minutes, when the arch became 

 broken into sections, and grad- 

 ually disappeared. The fol- 

 lowing diagram which I made 



at the time, will afford a tolera- 

 ble idea of the form of the 

 arch during its continuance. 



In conclusion I would re- 

 mark, that so far as I have ob- 

 served, the aurora borealis gen- 

 erally occurs in cahn weather, 

 and in summer it is almost uni- 

 versally the precursor of thun- 

 dev storms, and in winter, ot 

 snow and boisterous weather. 



Faycftcvilic Vl. May 2'L i83i. 



