34 Dr. and Mrs. Huggins. On the Bright [June 8, 



The probable analogy between the Nova and the remarkable 

 variable star ft Lyrae, in the spectrum of which also we have to do 

 apparently with bright and dark lines of the same substances, though 

 not in all cases identical with those of the Nova, in motion re- 

 latively to each other, which we ventured to point out in our former 

 communication on the Nova,* has been recently greatly strengthened 

 by the photographic observations of ft Lyrae at different stages of 

 its periodic variations by Dr. Belopolsky at the Observatory of 

 Pulkova. 



In some of his photographs, especially in one taken shortly after 

 the star's second maximum, bright lines come out near the positions 

 of the bright groups of the Nova which are now under discussion. 

 As the scale of Dr. Belopolsky's photographs is much smaller than 

 that of our diagram, we felt some hesitation in attempting any 

 identification of his lines with those of the Nova. At our request, 

 Dr. Belopolsky has been so kind as to put into our diagram the 

 two brightest of the lines of ft Lyrae, as they appeared shortly after 

 a second maximum, which fall within the brightest group of the Nova, 

 and which, indeed, may be identical with two of the lines in the Nova. 

 It may, however, be thought that the lines of ft Lyrae suggest that 

 they are independent bright lines rather than members of a group 

 such as that of the Nova. 



Whatever may ultimately be found to be the truth, there can be 

 no question as to the probable high significance of the remarkable 

 analogy which exists between the changes which take place in 

 ft Lyr and those which have been observed in Nova Aurigae. 



The two other spectra in the diagram represent respectively the 

 position and character of the two nebular lines, and the position of 

 the bright double or multiple band which was so brilliant in this 

 region of the Nova in the beginning of last year. 



2. "Bright Group near the Position of the Second Nebular Line. 



Not anticipating that our opportunities of observing were to be so 

 soon cut off, we gave our attention chiefly to the brighter group, in- 

 tending, after we had completed our observations and measures of 

 it, to attack seriously the second group. 



However, on nearly all the nights we observed we gave some 

 attention to this group, which, from being fainter, is more difficult 

 to resolve, though on the clearer nights it was fairly well seen with 

 the grating. 



Generally, the group may be described as of the same order as the 

 brighter one, consisting of bright lines and possibly of some absorp- 

 tion lines upon a feebly illuminated background. 



* ' Koy. Soc. Proc.,' vol. 51, p. 494. 



