52 



PROF. COPELAND AND DR L. BECKER ON THE 



Dr W. Huggins. Already in the daytime, before the star was visible, a message had 

 been forwarded to Greenwich Observatory. 



The remarkable nature of the star's spectrum once established, Dr Becker imme- 

 diately set about packing the most suitable apparatus to take to Dunecht, where the 

 15-inch refractor is fortunately still in perfect adjustment. Meanwhile I arranged to 

 keep a record of the star's magnitude, and try what could be done with the apparatus at 

 Calton Hill. Owing to the great loss of light in the universal spectroscope of the 24-inch 

 reflector, it soon became evident that only a few of the very brightest lines of the 

 spectrum could be measured therewith, while it was impossible when using it to obtain a 

 good general idea of the spectrum and its possible changes. Eventually I returned to a 

 small instrument of Vogel's pattern, which had proved useful on former occasions. * 

 With it were obtained, on February 9, a set of measures which eventually yielded the 

 following rough approximations to the positions of the principal bright lines in the 

 spectrum of the Nova : — 



Wave-length. 



Relative 

 Brightness. 



Remarks. 



mmm. 



657-1 



645 



594-2 



5621 



534-5 



519-3 



503-2 



495-25 



487-1 



450-8 



10 



2 

 3 

 6 

 10 

 5 

 3 

 4 

 1 



C. 



Edge of black band extending from C. 



Possibly an inaccurate place of D. 



Possibly carbon band or magnesium. 



Bright band near nebular line, but not identical therewith. 



Near nebular line, but also distinct therefrom. 



F. 



Extremely faint ; place very uncertain. 



Eespecting the brightness or "magnitude" of the star there is a telegram from 

 Professor Pickering of Harvard College, Cambridge, Mass., dated February 5 : — " Nova 

 bright on photograph December tenth, faint December first, maximum December twenty, 

 spectrum unique." This is understood to mean that the star could be detected on a 

 photograph taken on December 1, that it was brighter on December 10, and brighter 

 still on December 20. At least, this is the very probable reading offered by Professor 

 Krueger of Kiel. So far as is known, there is no certain record of the star's having 

 been seen or photographed previous to December 1, 1891. A faint star seen by Krueger 

 near to the spot, 1858, March 23, in one of the revisional zones of Argelander's Atlas, 

 has been identified in the heavens near to the Nova. Then we have Dr Anderson's 

 observations, January 23 to January 30 — Nova slightly brighter than x Auriga?, 4 "8 

 magnitude. 



From February 1 to 11 I have a complete set of estimations. These indicate a 



* See Copernicus, vol. ii. p. 105, for a description of this instrument. 



