appears to subsist between it and the Formation of Clouds. 41 



distinct. The whole appearances this evening showed in a 

 striking manner the influence of the aurora on the formation 

 and modification of clouds ; the cirrostrati being formed under 

 the eye from a thin, luminous vapour, which if not substantially 

 the aurora, was at least a substratum for its operations. 



" Nov. 22, a.m. A complete deluge of rain ; wind light from 

 E.S.E. and S.E. ; p.m. also very rainy. 8 h p.m. Cloudy, fair, 

 wind S.S.W. 10 h p.m. A remarkably interesting appearance 

 over the whole sky, of cirrostratus masses under a luminous haze. 

 These had a tendency to range W.N.W. to E.S.E., but were 

 chiefly in the form of small tufts of a dark hue, contrasting 

 curiously with the luminosity above them. The luminosity was 

 strongest in W.N.W., where it seemed to be decidedly (?) auroral, 

 but was also very obvious in every other part of the sky, the 

 light being, as I estimated, sufficient to allow of common hand- 

 bill type to be read by it. The light was indeed remarkable, 

 since there was no moonlight, and the sky was quite clouded. 

 The cirrostrati varied much in form in short intervals of time, 

 but seemed to retain nearly the same position. No luminous 

 pulsations similar to those noticed last night and on other occa- 

 sions were observed. 



" Dec. 16, 6* to 8 h p.m. Cirrostrati from S.S.W. to N.N.E. 

 faintly luminous between the dark streaks; hazy aurora in 

 N.N.W., arched, but without streamers. Long dark cirrostrati 

 occasionally shot from S.S.W. across the sky. It would almost 

 seem that the electric or electro-magnetic forces acting in certain 

 lines, separate aqueous vapour from the air which holds it in 

 solution, causing it to become visible and to assume a determi- 

 nate form. Between the radii in S.S.W. the luminosity was 

 sometimes very considerable. The aurora did not approach this 

 point, but its eastern limb extended to the N.N.E. point of ap- 

 parent convergence. 



"Dec. 17, 7 h to ll h p.m. A beautiful auroral display. The 

 greater part of the sky, except a portion in S.E., was at times 

 occupied by sheets and streamers. The corona was frequently 

 very well defined, with a marked contortion of the auroral beams 

 in its vicinity. The streamers were mostly white and yellowish, 

 with occasional patches of crimson and orange. Luminous 

 sheets frequently passed up towards the zenith with great rapid- 

 ity, these movements being apparently connected with the wind, 

 which blew in gusts most frequently whenever the luminous 

 sheets prevailed. The only clouds seen were cirrostrati, which 

 became more numerous and dense towards midnight. 



* 1849. Feb. 19, 8 h 30 m p.m. Aurora in N.N.W.up to about 

 60°, a few reddish streamers. 9 h 15 m . A splendid white zone, 

 2° or 3° broad, extended across the sky from W.S.W. to E.N.E., 



