SPECTRA OF SOME OF THE BRIGHTER STARS. 
705 
Carbon. 
a Herculis. 
5164-8 
5165 
5128-5 
5136 
5098-.3 
5107 
It will be seen that the coincidences are not very exact for the secondary maxima, 
hut the question is complicated by the fact that several dark lines appear in the same 
region, and the secondary maxima may therefore he masked. 
Further ^photographs will be taken with special reference to this region, special 
exposures being required, as the 2 :)hotographic plates in use are very slow for this ' 
part of the spectrum, and the instrument has to be specially focussed. 
Other regions of the spectrum have also been examined for bright flutings, more 
particularly with reference to the flutings of carbon. From a photograph of the 
spectrum of Mira Ceti taken by Professor Pickering, there is strong evidence of the 
existence of the carbon group, commencing at wave-length 4215‘6, but there are no 
decided indications of it in a Orionis. In the latter spectrum the dark lines are much 
more numerous than in Mira, and hence the bright fluting, if present, may be masked. 
It seems more likely, however, that the increased temperature, indicated by the 
greater number of lines in a Orionis, is the true explanation of the disappearance of 
the fluting, only the most persistent one—that at A 5165—remaining. There are 
no certain indications of the bright fluting of carbon commencing at X 4736 (see 
Plate 28). 
Sequence of Sqoectra of these Stars. 
Plate 26 shows the spectra of a Herculis, /3 Pegasi, a Orionis, and /3 Andromedse, 
arranged in the order of differences. This order has been chiefly determined by the 
flutings near X 4763 and X 4585, which gradually thin out in passing from a Herculis 
to /3 Andromedae. It will be seen also that the lines of calcium and some other lines 
thin out in the same order. 
Including the stars of which the spectra have not been rejiroduced, they have been 
arranged as follows, those bracketed together being indistinguishable from each other. 
■< 
' (3 Andromedae. 
a Ceti. 
V Bootis. 
a Orionis. 
Pegasi. 
a Scorpii. 
p Persei. 
4 X 
MDCCCXCIII.—A. 
