292 
ASTRONOMY: C. D. PERRINE 
the velocity distributions in these two classes may not depart widely 
from Maxwell's law, but that they are different from those in the spectral 
classes F, G, K and M. 
Conclusions. — 1. The radial velocities of the stars of classes B and A 
appear to decrease in general with increasing proper motion. There 
are, however, some inexplained anomalies. 
2. The velocity distributions of classes B~B5 and A differ from the 
distributions found for the F, G, K and M classes by Kapteyn and 
Adams, appearing to be more clearly in accord with Maxwell's law. 
3. The effects of the magnitude- velocity equation are clearly shown 
in the classification of the B and A stars made for this investigation. 
4. There are some indications of a small abrupt change in the velo- 
cities of both classes in the smaller proper motions. There are also 
some indications in the classes F, G and K of such a change but in proper 
motions somewhat larger than in the early classes. 
^Astrophys. 41, 318. 
2 These Proceedings, 1, 14. 
ASYMMETRY IN THE PROPER MOTIONS AND RADIAL 
VELOCITIES OF STARS OF CLASS B AND THEIR 
POSSIBLE RELATION TO A MOTION 
OF ROTATION 
By C. D. Perrine 
OBSERVATORIO NACIONAL ARGENTINO. CORDOBA 
Received by the Academy. April 8, 1916 
In the course of other investigations asymmetry in the proper motions 
of the B stars was suspected. A preliminary investigation has shown a 
systematic difference between the proper motions in the region about 
0^ and that opposite. The results of a comparison of the proper mo- 
tions in these two regions and also with the regions within 40° of the apex 
and the antapex of solar motion are given in the table. The average 
radial velocities of the stars (V2) are also included. 
An examination of the individual values shows a marked consistency 
in all of the regions. These results depend upon Campbell's catalog of 
class B stars in Lick Observatory Bulletin, No. 196. As is well known 
these stars have a marked preference for the Milky Way. 
The minima corresponding to the apices of the solar motion fall at 
and 19^. The two maxima corresponding to the parallactic motion 
of the Sun fall at 2^ and 13|^. These two points are almost exactly at 
right angles to the direction of the Sun's motion. 
