726 ON PHOTOGRAPHIC SPECTRA OF SOAIE OF THE BRIGHTER STARS. 
Giioup V.—Line absorption predominant, with decreasing’ temperature. 
Suh-group a.—The lines of hydrogen are still broad, and the line of calcium 
at X 4226 is clearly visible. The grouping of lines about G, which is 
so characteristic of the solar spectrum, is not visible. E.g., 
)8 Arietis, 
Sub-group /S.—All the solar lines are now clearly visible, but the hydrogen 
lines are broader than in the solar spectrum. The grouping at G 
is only partially developed. E.g., Procyon. 
Suh-group y .—The spectra very closely resemble the solar spectrum, the 
characteristic grouping of lines about G being fully developed. 
Carbon absorption commencing in the ultra-violet. E.g., Capella. 
Group VI.*—Carbon absorption predominant. 
Sub-division into Species. 
As more photographs become available for detailed examination, it will be possible 
to sub-divide the various sub-groups into species. Thus, in the case of the bright- 
line stars. Professor Pickering, agreeing with me in classifying the bright-line stars 
with the nebulse, has already divided the former into three types. In consequence, 
however, of there being less than 200 stars included in the present discussion, I have 
not thought it desirable to attempt the further sub-division in the present communi¬ 
cation. It is clear already that the species of Group II. given in my former commu¬ 
nication will hold good. 
In concluding this communication, I am anxious to express my obligations to those 
who have assisted me in the different branches of this inquiry. 
The chief labour entailed in taking the photographs has been borne by Messrs. 
Fowler, Baxandall, and Shackleton. It is impossible to overrate the zeal and 
the patience they have shown in the almost hopeless observing conditions of the last 
two years. Repeated visits to the observatory on the same night have often been 
made. Some of the photographs obtained at Westgate-on-Sea were taken by Mr. W. 
J. S. Lockyer. Mr. Fowler and Mr. Baxandall are chiefly responsible for the 
determination of wave-lengths, Mr. Fowler having also largely aided in the final 
discussion of the photographs. Messrs. Gregory and Fournier have assisted from 
time to time, and the photographic enlargements have been made by Sergeant 
Kearney and Corporal Haslam. 
* No photograplis of the spectra of stars of this group have yet been photographed at Kensington. 
So far as they are yet known, they are all below the fifth magnitude, and the investigation of their 
spectra is therefore almost impossible with the present means. With the instrument D the spectrum of 
152 Schj. could not be photographed with an hour’s exposure. 
