SPECTRA OF SOME OF THE BRIGHTER STARS. 
725 
Group I.—Radiation lines and fintings predominant. 
Sub-group a.* —Nebulm. 
Sub-group y8.—Bright-line stars. 
Group II.—Mixed fluting radiation and absorption predominant. Much con¬ 
tinuous absorption in the violet. 
Sub-group a. —Dark flutings probably extending from the red end to the 
region more refrangible than Gt (X 434). 
Sub-group /3.—Dark flutings extending as far as G. E.g., Mira Ceti. 
Sub-group y. —Stars in which the most refrangible dark fluting is at X 4585. 
E.g., a Herculis. 
Sub-group 8.—Stars in which the most refrangible dark fluting is at X 4763. 
In addition to the flutings there is a large number of dark lines. 
E.g., a Orionis. 
Group III.—Line absorption predominant, with increasing temperature. Less 
continuous absorption at the violet end. 
Sub-group a.— Stars with line spectra resembling those of Group II., Sub¬ 
group 8, but with only a single fluting in the red remaining. E.g., 
a Tauri. 
Sub-group y8.—Continuous absorption in violet less than in Sub=group a. 
The calcium lines are less intense, while lines at XX 4172, 4233, 
and 4177, have their intensity increased. E.g., y Cygni. 
Sub-group y. —Stars with spectra consisting of a relatively small number of 
dark lines. The hydrogen lines are of only moderate breadth, 
and among the additional lines are soine which are seen bright in 
the solar chromosphere. In this sub-group the continuous ab¬ 
sorption in the violet is almost a minimum. E.g., /3 Orionis. 
Group IV.—Simplest line absorption predominant, the hydrogen lines being 
very broad. 
Sub-group a. —The spectra are marked by the presence of fine lines at 
wave-lengths 4024, 4471, 4481, the two latter being of almost 
equal intensity. E.g., ^ Persei. 
Sub-group /3.—Highest temperature. The spectra show additional faint 
lines, and 4471 almost disappears. E.g., a. Andromedse. 
Sub-group) y. —The lines of iron make their appearance, but the line of 
calcium at X 4226 is not yet distinct. E.g., Sirius. 
* The Greek letters have been adopted to avoid confusion with the symbols employed in Vogel’s 
classification. 
t None of the stars of this sub-group have yet been photographed at Kensington, but their existence 
is indicated by the discussion of Donee’s observations, and on the hypothesis, there must be an inter- 
paediate stage between the bright-line stars and stars like Mira Ceti, 
