16 
ASTRONOMY: KAPTEYN AND ADAMS 
evident that if all of the stars moved accurately in the direction of these 
streams the radial velocity would be zero at those points where the line 
TABLE I 
Average Values of the Radial Velocity p in km. 
|type| 
PROPER MOTIOr 
AUTHOR- 
ITY 
X 60° to 90° 
X 0° 
to 49° 
TOTAL 
X 
pi 
X 
P2 
X 
p 
0 
000" 
to 0.029" 
w+c 
790 
8.9 
(25) 
32° 
13 
6 
(22) 
56° 
10.6 
(54) 
0 
030 
0.069 
c 
71 
8.5 
(9) 
29 
12 
5 
(11) 
48 
10.15 
(22) 
0 
070 
0.149 
c 
78 
12.3 
(17) 
34 
20 
5 
(17) 
53 
14.65 
(38) 
0 
150 
0.249 
c 
72 
11.5 
(22) 
32 
18 
9 
(12) 
58 
14.3 
(40) 
0 
250 
0.499 
c 
74 
16.7 
(24) 
33 
21 
1 
(8) 
62 
16.2 
(38) 
^0.500 
w+c 
73 
18.05 (30) 
43 
34 
9 
(18) 
62 
24 .4 
(48) 
G 
0 
000 
to 0.026 
w+c 
73 
6.9 
(37) 
32 
12 
8 
(32) 
54 
9.6 
(80) 
0 
027 
0.049 
c 
76 
9.6 
(10) 
37 
12 
8 
(13) 
54 
11.8 
(28) 
0 
050 
0.099 
c 
74 
9.5 
(18) 
27 
12 
3 
(7) 
61 
10.3 
(25) 
0 
100 
0.499 
c 
76 
14.95 (13) 
44 
23 
6 
(11) 
60 
19.0 
(28) 
^0.500 
w+c 
76 
22.9 
(51) 
37 
45 
6 
(31) 
60 
32.1 
(91) 
K 
0 
000 
to 0.025 
w+c 
76 
10.9 
(47) 
36 
12 
3 
(39) 
57 
11.7 
(91) 
0 
026 
0.039 
c 
73 
12.15 
(37) 
37 
11 
9 
(24) 
58 
11.7 
(68) 
0 
040 
0.059 
c 
75 
14.9 
(21) 
38 
21 
3 
(21) 
56 
17.9 
(50) 
0 
060 
0.079 
c 
75 
10.7 
(24) 
36 
15 
1 
(16) 
58 
12.3 
(41) 
0 
080 
0.099 
c 
74 
15.7 
(26) 
34 
14 
0 
(10) 
62 
15.2 
(36) 
0 
100 
0.119 
c 
76 
20.7 
(12) 
32 
22 
6 
(15) 
52 
23.4 
(31) 
0 
120 
0.149 
c 
73 
16.5 
(24) 
39 
23 
8 
(10) 
62 
19.0 
(36) 
0 
150 
0.199 
c 
74 
15.6 
(24) 
39 
24 
5 
(10) 
62 
18.2 
(34) 
0 
200 
0.299 
c 
75 
16.5 
(18) 
32 
24 
3 
(13) 
56 
20.4 
(37) 
0 
300 
0.599 
c 
73 
33.3 
(12) 
33 
47 
05 (7) 
58 
38.35 
(19) 
^0.600 
w+c 
74 
23.5 
(25) 
34 
23 
0 
(28) 
53 
22.5 
(58) 
M 
0 
000 
to 0.029 
w+c 
76 
12.9 
(18) 
36 
18 
1 
(15) 
58 
14.4 
(40) 
0 
030 
0.089 
c 
79 
15.0 
(19) 
36 
21 
0 
(11) 
62 
17.0 
(34) 
0 
090 
0.499 
c 
77 
17.9 
(14) 
35 
28 
9 
(7) 
62 
20.7 
(24) 
^0.500 
w 
71 
53.2 
(4) 
71 
53.2 
(4) 
P2/P1 
Obs. 
1.53 
1.47 
1.67 
1 64 
1.26 
1.93 
1.86 
1.33 
1.30 
1.58 
1.99 
1.13 
0.98 
1.43 
1.41 
0.89 
1.09 
1.44 
1.57 
1.47 
1.41 
0.98 
1.40 
1.40 
1.61 
The- 
ory 
1.63 
1.56 
1.58 
1.55 
1.54 
1.39 
1.55 
1.53 
1.63 
1.41 
1.51 
1.52 
1.47 
1.49 
1.50 
1.52 
1.58 
1.43 
1.45 
1.56 
1.52 
1.52 
1.52 
1.55 
1.56 
of sight is at right angles to the stream motion; that is, where X = 90°. 
On the other hand the motion would be altogether radial -at the vertices 
themselves; that is, p should be large for X = 0°. Since the motions of 
the stars do not in general coincide with the stream motion, but only show 
a preference for directions differing but little from it, the contrast in 
the amount of the radial motion at X = 90° and X = 0° will be less marked. 
This amount can, of course, be calculated as soon as we have derived 
complete elements for the two streams from a consideration of the proper 
motions. As it is, different theories give sHghtly different values,^ and 
Eventually these differences may serve to determine the theory to be 
