72 
ASTRONOMY: C. D. PERRINE 
average ju of the entire 28 stars is but 0".037, or omitting the largest two, is 
but 0".030. The criterion of proper motion, therefore, indicates that these 
stars are at the same general distance as the class B stars. 
The stars of table 2 also show a decided preference for the galaxy, half of 
them being within 15° and three-quarters of them within 40° of the galactic 
plane. This is significant when it is considered that the principal stars of 
these pairs belong almost entirely to the middle and later types of spectra. 
TABLE 1 
Fainter Component op Later Type 
MA GN ITUDE 
A 
SPECTRAL CLASS 
BRIGHTER 
s 
COMPONENT 
MA GNIT UD K 
Brighter 
Fainter 
5.6 
0.9 
A 6 
G 5 
0.143 
„ 
23.7 
5.2 
2.6 
F 5 
G 
.295 
49.4 
6.0 
0.7 
Ac 
A 2 
25 
16.6 
3.0 
3.3 
B 6 
A 0 
52 
117.3 
4.9 
0.6 
B 8 
A 0 
82 
7.8 
1.3 
6.3 
B 8 
G 
.247 
176.7 
5.3 
1.8 
T? 
-T 0 
rv 
.289 
288.1 
5.4 
1.4 
A 0 p 
A 3 
29 
145.3 
0.3 
1.4 
Go 
K 6 
3.67 
21.9 
2.9 
2.2 
A 2 
F 5 
.131 
231.0 . 
4.5 
2.2 
F 0 
K 0 
.169 
108.3 
4.3 
2.2 
B 3 
A 
34 
41.3 
4.9 
2.7 
A 2 
F 
65 
88.8 
6.0 
0.6 
B 8 
A 
38 
21.7 
5.8 
0.8 
B 3 
A 
22 
35.7 
4.6 
1.9 
A 3 
G? 
.230 
6.9 
5.8 
0.7 
B 3 
B 5 
18 
22.4 
3.6 
2.5 
A 5 
K 0 
.107 
337.1 
4.8 
2.7 
B 6 
A 
10 
22.8 
Var.3.4 
4.4 
B 2 
B 3 
8 
46.0 
'6.7 
0.9 
Bo 
B 9 
13 
183.4 
] 
6.8 
0.8 
B 5 
B 9 
13 
136*1 
] 
6.7 
0.1 
Bo 
B 5 
13 
236.3 
6.8 
1.0 
B 5 
B 9 
13 
192.4 
4.2 
1.7 
B 9 
A 0 
.121 
26.9 
4.8 
4.8 
Ap 
K 
.138 
222.8 
Further evidence is found in 19 of the Harvard stars which have com- 
posite spectra and in 62 stars of Campbell's Catalog of Spectroscopic Binaries, 2 
in which the spectra of both components have been observed or strongly 
suspected. 
For both spectra to appear on a photograph, the difference in brightness 
of the components of close binary stars will usually be small. On account 
of the tendency for components of nearly the same brightness to have similar 
2 Lick. Obs. Bull, Berkeley, 6, 1910, (46). 
