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XII. On the Spectra of some of the Fixed Stars. By William Huggins, F.R.A.S . , 
and W. A. Miller, M.D., LL.D ., Treas. & V.P.B.S . , Professor of Chemistry , 
King's College , London. 
Received April 28, — Read May 26, 1864. 
§ I. Introduction. 
1. The recent discovery by Kirchhoff of the connexion between the dark lines of 
the solar spectrum and the bright lines of terrestrial flames, so remarkable for the wide 
range of its application, has placed in the hands of the experimentalist a method of 
analysis which is not rendered less certain by the distance of the objects the light of 
which is to be subjected to examination. The great success of this method of analysis 
as applied by Kirchhoff to the determination of the nature of some of the constituents 
of the sun, rendered it obvious that it would be an investigation of the highest interest, in 
its relations to our knowledge of the general plan and structure of the visible universe, to 
endeavour to apply this new method of analysis to the light which reaches the earth from 
the fixed stars. Hitherto the knowledge possessed by man of these immensely distant 
bodies has been almost confined to the fact that some of them, which observation shows 
to be united in systems, are composed of matter subjected to the same laws of gravita- 
tion as those which rule the members of the solar system. To this may be added the 
high probability that they must be self-luminous bodies analogous to our sun, and pro- 
bably in some cases even transcending it in brilliancy. Were they not self-luminous, it 
would be impossible for their light to reach us from the enormous distances at which, 
the absence of sensible parallax in the case of most of them shows, they must be placed 
from our system. 
The investigation of the nature of the fixed stars by a prismatic analysis of the light 
which comes to us from them, however, is surrounded with no ordinary difficulties. The 
light of the bright stars, even when concentrated by an object-glass or speculum, is 
found to become feeble when subjected to the large amount of dispersion which is 
necessary to give certainty and value to the comparison of the dark lines of the stellar 
spectra with the bright lines of terrestrial matter. Another difficulty, greater because 
it is in its effect upon observation more injurious, and is altogether beyond the control 
of the experimentalist, presents itself in the ever-changing want of homogeneity of the 
earth’s atmosphere, through which the stellar light has to pass. This source of difficulty 
presses very heavily upon observers who have to work in a climate so unfavourable in 
this respect as our own. On any but the finest nights the numerous and closely approxi- 
mated fine lines of the stellar spectra are seen so fitfully that no observations of value 
