38 Dr. and .Mrs. Hugging. On Wolf and [Dec. 11, 



is, to about \ 4698. His curve gives the brightness of the maximum 

 over that of the first line as about 7 to 6, whereas the normal relative 

 intensity of these two lines is in the inverse direction and as about 

 2 to 4 (Watts, 'Index of Spectra,' p. 30). 



A similar change from the normal relation of brightness of the 

 flatings within the band, even if removed to X 468, does not seem to 

 us to bring the star band sufficiently into accordance in character and 

 position with those of the band of the hydrocarbon flame to justify 

 us in attributing the blue band in the star to carbon. Though we 

 traced the band a little further towards the red, than the position of 

 the beginning of the band given by Vogel's measures, yet it is very 

 faint, and without any increase in brightness at the place of the second 

 fluting of the carbon band, beyond which we were unable to see it. 



According to Hasselberg's curve, the second bright fluting, where 

 in our instruments the star band ends, still retains a brightness of 

 about 11/12 of that of the maximum, and the first line, at the position 

 of which no brightening of the feeble continuous spectrum of the 

 star could be detected, a brightness of about 6/7 of that of the 

 maximum. That the flutings of the band were not obscured by the 

 absorption band at this part of the spectrum appears clear from the 

 circumstance that we could trace the faint continuous spectrum up to 

 the bright band. 



Vogel's and our observations agree in making the band run on 

 some distance beyond the visible termination of the blue band of the 

 Bnnsen flame. Piazzi Smyth, under some conditions, observed a 

 large number of faint " linelets " beyond the " 5th leader " of the band, 

 where its visibility usually ends ; and in the brilliant light of the arc 

 the band can be traced further in the blue. The extension of the 

 band under such circumstances does not seem to us to affect our 

 present argument ; for in the very feeble light of the star we may 

 Bnrely take it that the carbon band, if present, could not be seen to 

 extend further than its usual visible limit in a Bunsen flame, namely, 

 about X 468. 



Perhaps it should be stated in connexion with the circumstance 

 that we saw the band extend a little further towards the red than 

 Vogel did, that at the time of our observations the hydrogen line at 

 F was not visible in our instruments, whereas it was bright at the 

 time when Vogel observed the star. In the spectrum of a similar 

 star, D.M. +37 3821, in which the hydrogen line at F at the time 

 was bright, the blue band was seen by us to stop near the place given 

 by Vogel in his measures of the star No. 4001. 



Not only is there no coincidence, so far as Vogel and we have 

 observed, of the position of the band in the star with that of the blue 



* ' Mem. de 1'Acad. Imp. dee Sciences de St. Petersbourg,' TO!. 22, No. 2, 1880, 

 p. 82. 



