SPECTRA OF SOME OF THE BRIGHTER STARS. 
715 
Professor Pickering’s Table of Bright Lines. 
Planetary nebulae. 
Bright-line stars. 
Type I. 
Bright-line stars. 
Type II. 
Brig’ht-line stars. 
Type III. 
501 
486 
486 
486 
470 
469 
469 
462 
464 
464 
, , 
454 
455 
455 
» • 
451 
451 
447 
447 
443 
434 
434 
434 
434 
420 
420 
421 
410 
410 
410 
412 
, * 
406 
406 
407 
• • 
402 
402 
397 
398 
397 
• • 
395 
395 
388 
389 
389 
The main point of difference is that the chief nebular line near X 5006 is not 
seen in the spectrum of bright-line stars, and this no doubt is due to the relative 
absence of feeble collisions as condensation goes on. The brightening of this line in 
the spectra of Nova Cygni and Nova Aurigm, as the stars faded away, is sufficient 
evidence that it is associated with low teinperature, and hence it is not surprising 
to find that it is absent from the spectra of the bright-line stars, which on this 
hypothesis are hotter than the nebulae, since they are more cojjdensed, 
I have stated that we should expect— 
(a.) The carbon flutings, and 
(6.) The continuous spectrum to be brighter than in nebuhe, while 
(c.) The hydi’Ogen lines are fainter. 
(a.) I may add, by way of reminder, that in my previous discussion of these 
bodies * I showed that there was evidence of a very considerable amount 
of carbon radiation in the visible region of the spectrum. Subsequent 
work at Kensington and Westgate, and an examination of Professor 
Pickering’s photographs have strengthened this view. The photogra])hs 
show a band which agrees very closely in position with the band of 
carbon commencing at X 4736, but which under certain conditions has its 
brightest part at X 468.t A full discussion of this question will form 
the subject of a future communication. 
* ‘Roy. Soc. Proc.,’ vol. 44, pp. 33-43. 
t Ibid., p. 38. 
4 Y 2 
