SPECTRA OF SOME OF THE BRIGHTER STARS. 
707 
a close double with the iron line X 4405, being slightly less refrangible. It is a very 
strong line in a photograph of the spectrum of a Tauri taken at Kensington, on 
November 20, 1888, and is seen in the spectra of all the stars resembling a Tauri 
or a Orionis. A photograph taken on September 15,’1892, with the instrument B 
shows the line strongly marked. 
It will be evident from a comparison of the photographs that these stars bear a 
close relationship to those of Sub-division a. The increased brightness of the violet 
end of the continuous spectrum, in conjunction with the fading out of the flutings, 
may be taken as an indication of increased tem^^erature in passing from Sub-division a 
to Sub-division (3. 
VIII.—THE GEN'ERAL SEQUENCE OF THE SPECTRA OP THE STARS NOW 
UNDER DISCUSSION. 
(1.) Sequence of Sub-divisions. 
We have now before us the facts relating to the various spectra which have been 
photographed at Kensington, and the next thing to do is obviously to attempt to 
trace the relationships of the various sub-divisions to which reference has been made. 
Two Series of Spectra. 
One important fact comes out very clearly, namely, that, whether we take the 
varying thicknesses of the hydrogen or of the lines of other substances as the basis for 
the arrangement of the spectra, it is not possible to place all tbe stars in one line of 
temperature. For example, in the stars of Table A, Sub-division a, the hydrogen 
lines are of the same average thickness as in the stars of Table A, Sub-division /3, but 
the remaining lines are almost entirely different; and the two sub-divisions cannot be 
placed in juxtaposition. It is, therefore, necessary to arrange tbe stars in two series. 
This has been done, and the general results of the investigation are shown in Plates 26, 
27, and 29, where the spectra of eighteen typical stars are arranged in order of differ¬ 
ences. The corresponding sub-divisions are as follows :— 
Bcference to Plates 26 and 27. 
Typical stai-s. 
Sub-divisions. 
a Andromedae . 
. Table A, sub-division y 
2 
/S Persei. 
• • y J ? ? ? ? 
1 
^ Orionis. 
•• ?? 5 ) 3 ? ^ 
4 
y Orionis. 
3 
yS Orionis. 
2 
4x2 
