532 
ASTRONOMY: R. G. AITKEN 
of double stars of every magnitude class rise to sharper maxima in the 
Milky Way than do the corresponding curves of the stars in general. 
This is most strikingly exhibited in Table II which gives the per- 
centage of double stars in the Milky Way zone, the 20° zone on either 
side of it, the area north of + 30° and that south of — 30° galactic latitude. 
TABLE I 
The Distribution of Double Stars by Magnitude Classes and Zones of Galactic 
Latitude 
ZONE 
MAG. 
TO 6.5 
MAG. 
6,6-7.0 
MAG. 
7.1-7.5 
MAG. 
7.6-8.0 
MAG. 
8.1-8.5 
MAG. 
8.6-9.0 
TOTAL 
I 
19 
13 
14 
29 
40 
84 
199 
II 
43 
28 
50 
68 
114 
193 
496 
Ill 
60 
43 
56 
79 
148 
254 
640 
IV 
96 
54 
81 
132 
232 
401 
996 
V 
121 
88 
133 
249 
376 
653 
1620 
VI 
84 
51 
81 
134 
221 
395 
966 
VII 
28 
23 
18 
54 
90 
154 
367 
VIII 
7 
6 
5 
12 
31 
55 
116 
Total 
458 
306 
438 
757 
1252 
2189 
5400 
Areas of all galactic latitudes were examined in winter, others are as 
in summer; the larger part of the work done with the 12-inch telescope 
lies between +27° and —3° galactic latitude; nearly the entire area 
south of —3°, and also the high northern galactic latitudes, were sur- 
veyed with the 36-inch refractor. The apparent increase in percentage 
in the Milky Way zone is therefore not due to the use of different tele- 
scopes nor to any other peculiarity in the collection of the data, and we 
must conclude that close visual double stars are relatively more numerous 
in the Milky Way than elsewhere in the sky. 
TABLE II 
Percentages of Double Stars 
GALACTIC LATITUDE 
B. D. STARS TO 9.0 
DOUBLE STARS 
PERCENTAGE 
OF DOUBLE STARS 
-f90° to +30° 
26948 
1335 
4.95 
-f-30 to 4-10 
19355 
996 
5.15 
-MO to -10 
26477 
1620 
6.13 
-10 to -30 
17831 
966 
5.13 
-30 to -70 
10368 
483 
4.66 
I have tabulated the double stars in distance classes by steps of 0''.5 
and find that the increased density toward the Milky Way is exhibited 
by stars of every class, though the percentages in Table II are most 
strongly affected by the close pairs because of their greater number. 
