No. III.] 



Dr. RICHARDSON ON THE AURORA. 



601 



scarcely visible to the naked eye, and were most readily detected by their 

 melting upon the skin. The same phenomenon, of an almost imperceptible 

 snow falling from a clear sky, had been before observed in a bright sun, 

 which rendered visible a great number of icy spiculse floating in the air. 



1820, December 1st. During the day, the sky kept tolerably clear, a slight 

 appearance only of the stratus being visible near the horizon ; but a snow, 

 whose particles were so minute as to be discerned only in the sunshine, fell 

 at intervals during the forenoon. At noon, the snow was more apparent, and 

 a bow was produced in the neighbourhood of the sun's place in the heavens. 

 At 8h. p.m. Wind E.N.E., light, with a very clear sky. 



The Aurora commenced by a beam shooting up from the northern horizon ; 

 afterwards masses of light appeared in various parts of the sky, particularly 

 in the eastern quarter ; and at length an arch was formed from S.E. to N.W. 

 The centre of the arch, when it was first formed, lay to the northward of the 

 zenith, but afterwards passed gradually to the southward. When about 60° 

 above the southern horizon, it assumed the falcate appearance, described on the 

 24th November, the pointed tails directed towards the north. The falci-form 

 processes sometimes separated laterally, so as to appear like parallel beams 

 crossing the line of direction of the arch obliquely. Their altitude was not 

 altered at the moment of their separation. At times the general arch was 

 dispersed, and a number of small arches formed, whose ends occasionally 

 rolled inwards upon themselves in form of a scroll. The whole body of the 

 light ultimately descended below the southern horizon and disappeared ; not a 

 cloud was visible during the evening. 



December 2nd. Wind in the morning, N. E. , inclining to snow. Ther. — 1 4° 

 at 9h. p.m., - 6°, wind N.N. W. Hazy weather, no stars visible. A faint arch 

 of the Aurora from N.W. to S.S.E. 



December 3d, 1820. 



Hour. Temp. Wind. 



A.M. 9 -0 N.N.W. Fresh Hazy weather. 

 Noon +6 do. do. Small snow. 



P.M. 4 +5 do. do. Cloudy. No mist rising from the rapid. 

 9 4-4 do. do. do. 



Snow during the night. No Aurora observed. 



4 H 



