Royal Society. 311 



a few bright lines, which indicate that the light by which it is formed 

 was emitted by matter in the state of luminous gas *. These spectra 

 are represented with considerable approximative accuracy in a diagram 

 which accompanies this paper. 



fcpectrum of Absorption and Spectrum of Bright Lines forming the Compound 

 Spectrum of a New Star near e Coronse Borealis. 



Description of the spectrum of absorption. — In the red a little 

 more refrangible than Fraunhofer's C are two strong dark lines. 

 The interval between these and a line a little less refrangible than D 

 is shaded by a number of fine lines very near each other. A less 

 strongly marked line is seen about the place of solar D. Between 

 D and a portion of the spectrum about the place of b of the solar 

 spectrum, the lines of absorption are numerous, but very thin and 

 faint. A little beyond b commences a series of close groups of strong 

 lines ; these follow each other at small intervals, as far as the spectrum 

 can be traced. 



Description of the gaseous spectrum. — A bright line, much more 

 brilliant than the part of the continuous spectrum upon which it falls, 

 occupies a position which several measures make to be coincident 

 with Fraunhofer's Ff. At rather more than one-fourth of the 

 distance which separates F from G, a second and less brilliant line 

 was seen. Both these lines were narrow and sharply denned. 

 Beyond these lines, and at a distance a little more than one-third 

 of that which separates the second bright line from the strongest 

 bright one, a third bright line was observed. The appearance of 

 this line suggested that it was either double or undefined at the 



* The position of the groups of dark lines shows that the light of the pho- 

 tosphere, after passing through the absorbent atmosphere, is yellow. The light, 

 however, of the green and blue bright lines makes up to some extent for the 

 green and blue rays (of other refrangibilities) which have been stopped by ab- 

 sorption. To the eye, therefore, the star appears nearly white. However, as 

 the star flickers, there may be noticed an occasional preponderance of yellow 

 or blue. Mr. Baxendell, without knowing the results of prismatic analysis, de- 

 scribes the impression he received to be " as if the yellow of the star were seen 

 through an overlying film of a blue tint." 



t On the 17th, the lines of hydrogen, produced by taking the induction-spark 

 through the vapour of water, were compared in the instrument simultaneously 

 with the bright lines of the star. The brightest line coincided with the middle 

 of the expanded line of hydrogen which corresponds to Fraunhofer's F. On 

 account of the faintness of the red end of the spectrum, when the amount of dis- 

 persion necessary for these observations was employed, the exact coincidence of the 

 line in this part of the spectrum with the red line of hydrogen, though extremely 

 probable, was not determined with equal certainty. 



