390 PROFESSOR C. MICHIE SMITH ON OBSERVATIONS ON 



low-sun band close to the horizon, which left the strip of yellow between that 

 band and the rain-band by far the most prominent feature in the spectrum. 



September 13th. — In the early morning there was a good deal of distant light- 

 ning. The sun rose of a bright golden yellow colour; no green was seen. In 

 the afternoon there were slight showers. A most remarkable observation 

 made this morning by Mr Pogson seems very difficult to explain, except by 

 some form of auroral display. I give his notes in full : — 



"September 12, 1883, 17 h m , Madras mean time. — The sky a most 

 remarkably intense reddish-yellow, so unusually bright that I called up my 

 daughter Isis to witness it. A dark cloud bank from about east to south, and 

 the vivid light above uncommonly auroral in appearance; more so than anything 

 I have seen here before. 



"At 17 h 10 m , the red hue considerably diminished, and bright orange 

 yellow the prevailing tint. The light quite bright enough to make notes by. 



" At l7 h 20 m , the dark blue-black stratum now from about north to east, 

 and very near the horizon. Sky tolerably clear to about 20° altitude, but of a 

 rich red tint, with bright yellow clouds above, beginning at about 30° and 

 covering the east of the sky. 



"At 17 h 30 m , all changed within the last four or five minutes, and 

 writing now difficult without a lamp. A thick dark red stratum over the 

 sunrise point, and everywhere else a very greenish-yellow. 



"At 17 h 40 m , the low cloud stratum now sea-green. Light only enough 

 to write by with difficulty. 



" At 17 h 50 m , sun rising a bright yellowish-white, and otherwise nothing 

 extraordinary, all unusual tints having disappeared with the sunrise." 



September 1-lth. — Before sunrise the clouds were blue and grey, with patches 

 of red. Clouds of all sorts, — cirrus, nimbus, stratus, cumulus, and mare's tails. 

 Two bright flashes of lightning about 5.30 a.m. In the evening there was a 

 slight green tinge, and after sunset the sky was golden red till 6.50, while 

 mercury seen through the red haze was twinkling strongly. 



September 15th. — The sun rose golden. In the evening the sunset was very 

 fine ; in the west the colour was golden to orange yellow, in the east it was 

 greenish; red clouds remained till 7.5 ; there were very brilliant red " rayons de 

 crdpuscule." 



From September 15th to September 20th the sunrises and sunsets were very 

 fine, with red and gold for more than half an hour before sunrise and after sunset. 



September 21st. — Sunset normal. 



September 22nd. — The sun rose as a yellow ball, and showed distinct greenish- 

 fellow afterwards. From ten minutes before till sunset, the sun was greenish- 

 yellow, but the sun was much brighter than on the 10th and 11th. 



September 23rd. — The sun rose very green. At 5.37 p.m. the sun appeared 



