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to D on the less refrangible side, and, in order to make assurance 
double sure, he passed the light from a candle through the spectroscope, 
and saw the bright sodium lines very near to the cross. 
Subsequently, Mr. Christie, of the Greenwich Observatory, had 
announced his own observation of the partial covering up of the red 
end of the spectrum by absorption bands, and the distribution of 
similar ones over other parts of the continuous spectrum, but that he 
could not fix their position. D’Arrest and Huggins had also seen 
them. Mr. Lockyer remarked that the blue rays were absent. So 
the testimony of different astronomers respecting absorption bands in 
the spectrum of the nucleus amply confirmed what he observed under 
greater difficulties. 
There were but few records as to the colour of the light of comets, 
Lockyer observed that the nucleus and head of their late visitor were 
orange-yellow. With different telescopes, he had noticed that the 
nucleus was a brilliant white, very slightly tinted with yellow, and the 
coma very delicately tinted with bluish-green. It appeared to him 
that the spectroscope was the best umpire in such matters, And it 
was well-attested that the brightest band of the spectrum of the coma 
was the green one, while the brightest part of the continuous spectrum 
of the nucleus was between the yellow and the green, from which one 
would infer a whitish light just tinted with yellow ; and, as the rays on 
the red side of D were absorbed, they should not expect the light of 
the combined rays remaining to be orange. 
There yet remained unanswered a question of great interest. 
Was the light of comets their own light, or was it reflected from 
another source? The first part was answered in the affirmative by 
the spectroscope, for, in respect of the band spectrum, doubtless its 
source must be in the comet itself But as to the continuous spectrum 
the reply had yet to come. The polariscope, in the hands of Messrs. 
Huggins, Christie, Ranyard, and others, gave an unanimous verdict 
that a part of the comet’s light was reflected light. Huggins had 
estimated its proportion at one-sixth. But reflected from what? In 
connection with this question, Mr. Hind’s recent remark was of great 
value. He had said that the impossibility of seeing the late comet by 
day, even in the most powerful telescopes, had afforded additional 
evidence that proximity to the earth is not so important a condition 
for visibility of a comet in the daytime as close approach to the sun, 
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