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XXII. — Observations on a Green Sun and Associated Phenomena. By Professor 



C. Michie Smith. (Plate XL VII.) 



(Read July 7, 1884.) 



The appearance of a green or blue sun, though not unknown, is of sufficiently 

 rare occurrence to make a full investigation of all the phenomena connected 

 with it highly desirable. I have therefore tried to obtain as accurate and 

 complete information as possible concerning the appearance of a green sun in 

 India during several days in September 1883. 



The general features of the phenomena were well seen in Madras, and will 

 probably be best described by my notes taken at the time. On September 9th 

 the sun before setting assumed a peculiar silvery appearance, and its brightness 

 was so much decreased that for about half an hour before sunset it could be 

 observed with the naked eye. This was observed, I believe, though to a less 

 extent, on the two days preceding, but I did not myself see it on these days. 

 On September 10th, from 5.0 to 5.30 p.m., the sun could easily be looked at 

 with the naked eye, yet the limbs were sharply defined. At 5.30 the sun 

 entered a low bank of clouds, and did not fully reappear again, but a narrow 

 strip seen through a rift in the cloud at 5.43 was coloured a bright pea green. 

 Round Madras this colour had been seen in the morning, but in Madras itself 

 clouds concealed the sun till it had risen to a considerable altitude. Of the 

 morning of the 11th I have no record, but in the evening the green colour was 

 very brilliant, and was visible for more than half an hour, being preceded, as on 

 the former night, by the silvery white appearance of the sun's disc. On this 

 evening a large sunspot about one foot long was so conspicuous an object that 

 it attracted the attention of even the most casual observers. 



September 12th, at 12.35 a.m., the moon, which was near the horizon, appeared 

 a pale green. Bright stars near the horizon showed the same tint. From 5.15 

 to 5.30 the clouds to the east were coloured reddish-brown. At 5.55 the sun 

 rose with a yellowish-green colour, but was almost instantly lost in clouds. It 

 reappeared at 6.4, and was then of a bright green colour ; this colour rapidly got 

 fainter, but was quite perceptible till 7 o'clock. In the afternoon, the phenomena 

 of the previous nights were repeated, and the horizon being free from clouds, 

 the actual sunset was observed. The entry in my notes is — "6.3, the sunset 

 as a greenish-yellow ball, cumulus, stratus, and nimbus clouds near the horizon, 

 but moon fairly clear. Some blue sky, but hazy." The change from green to 

 greenish-yellow was evidently due to the great increase in the strength of the 



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