610 



APPENDIX. 



[No. III. 



sky prevailed ; but in the S. E. and N. W. (true), the clouds were more dense, and 

 presented various depending fringes towards the points of the horizon already 

 mentioned. The magnitudes of the masses, too, in different parts of the sky, 

 diminished so regularly, as they receded from the zenith, as to convey an idea 

 that their long sides were seen in the N.E. and S.W. quarters of the sky, but 

 their ends only in N.W. and S.E. quarters. 



At midnight, several of the cirriform clouds, which were in the neighbourhood 

 of the moon's place, reflected her light strongly, and hence appeared to have a 

 pretty dense structure; but, when they passed before the face of that luminary, 

 they became nearly invisible, producing only a slight halo or bur, but not sen- 

 sibly diminishing the light. 



At 20m. after midnight, the northern quarter of the sky became perfectly 

 clear to the height of 35°, the rest of the heavens being overspread by small 

 fleecy clouds, separated by narrow intervals. The edge of cloud border- 

 ing on the clear sky was well defined, ran east and west, and was made up of 

 the ends of small and rather broad parallel bars, having a direction from north 

 to south : a very common modification of cirrus. The moon was at this time 

 wading through a collection of small clouds, and was surrounded at the 

 distance of 10° by a faint, though distinct, halo. In the S. W., in a clear part 

 of the sky, there existed a small spot of yellowish white light, which for a few 

 seconds gradually increased in brightness, and then sent forth suddenly a lu- 

 minous beam, which crossing a portion of the deep blue sky, passed over the 

 well marked edge of cloud above described, continued its course in front of 

 the clouds, brightly illuminating their faces, and terminated to the southward 

 of the zenith near the moon's place in the heavens. When this beam had at- 

 tained its extreme length, it formed a half-arch concave to the westward. It 

 was scarcely formed, however, before it divided into a number of small parts, 

 which being segments of circles, and rising successively one above the other, 

 formed a kind of tiled arch. It disappeared altogether in three or four mi- 

 nutes, leaving the clouds unaltered in appearance. 



At 12h. 40' the sky had become clear as far as the zenith. The edge of 

 the clouds, which was now overhead, was still composed of parallel bars, di- 

 rected to the north and south. Under these bars, a few streaks or threads of 

 very rare cloud were seen floating, and, at times, emitting a faint orange-co- 

 loured light. The clouds in the southern part of the sky, although they 



