: 
Photographic Spectra of Stars. 373 
Art. XLVIIL— On the Photographic Spectra of Stars.* 
THE author presented, in December, 1876, a preliminary 
note on the subject of this paper, together with a diagram o 
the spectrum of Vega coined with that of the sun. 
he author refers to a paper by Dr. William Allen Miller 
and himself in 1864, in which they describe an early attempt 
to oe the spectra of stars. 
ther investigations prevented the author from resuming 
this line of research until 1875, when a more perfect driving 
clock, by Grubb, enabled him to take up this work with greater 
prospect of success. 
The author describes the special apparatus and the methods 
of working which have been em ed. 
In consequence of the very limited amount of light received 
from the stars, it was of great importance not to spread out the 
Spectrum to a greater extent than was necessary for a sufficient 
Separation of the principal lines of the spectrum. The spec- 
ultra-violet. The definition is so good that in photographs of 
the solar spectrum at least seven lines can be counted between 
and K, 
* Abstract of paper by W. Huggins, D.C.L., LL.D., F.R.S., read before the 
Royal Society, eee 18, 1879, with additions by the author.—Naiure, Jan. 22. 
Am. Jour. Sct.—Tuinp Serres, Vou. XIX, No. 113.—May, 1880. 
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