596 
ASTRONOMY: W. H. WRIGHT 
SOME PROBABLE IDENTITIES IN WAVE-LENGTH IN NEBULAR 
AND STELLAR SPECTRA* 
By W. H. Wright 
LICK OBSERVATORY. UNIVERSITY OF CALIFORNIA 
Presented to the Academy. October 22, 1 9 1 5 
Coincidence between the bright nebular Hnes and Hnes in the spectra 
of the stars and terrestial sources are usually regarded as limited to the 
radiations of hydrogen, helium, the line at wave-length 4686A, and the 
related series of ^ Pup pis lines. There are other correspondences to 
which attention should be drawn. There is in the nebulae a very faint 
line close to H5 which became pronounced enough in the spectrum of 
Nova Geminorum no. 2 to modify very perceptibly the form of the H5 
band. In fact it was first suspected in the nova from this circumstance, 
and afterward found, with prolonged exposure, in a number of nebulae. 
Its wave-length is uncertain on account of its faintness and the over- 
powering strength of the H5 line which, with the low dispersion used, 
is very close. The mean of five measures gives 4097. 6A. The wave- 
length of the dark line in e Orionis is, according to R. H. Curtiss,i4097.5A. 
This stellar line has been the subject of m^uch discussion in studies of 
spectral classification. It has its maximum, according to Miss Cannon, 
in Class Oe stars. It has been assigned by various observers to as many 
elements, but the best case seems to have been made out by Lockyer, 
Baxendall and Butler who identify it with a line of abnormal behavior 
in the spectrum of nitrogen. ^ Whatever its chemical source its strength 
in Class 0 stars argues for its common origin in these and in the nebulae. 
A Une which plays an equally, or perhaps more, important part in 
stars a little further along in their development is 4267. 30A. This is 
universally ascribed to carbon, and the wave-length quoted is Hart- 
mann's laboratory determination made with a highly rarefied tube 
containing a gaseous hydrocarbon compound. A faint nebular line 
has been photographed in this vicinity by several observers, but only 
rough determinations of its position have been published. The mean 
of five of my measures places it at 4267. 28A. The line is very faint and 
this value may be in error, say 0.2 of an angstrom. The South Kensing- 
ton observers have found^ the carbon line 4267.30 to be accompanied 
by a doublet in position 4647.53, 4650.92. If this doublet were in 
the nebulae it would not be resolved on these plates but would be repre- 
sented by an apparently single line of slightly greater wave-length than 
* See note on previous title, p. 590. 
