240 
ASTRONOMY: ADAMS AND JOY 
4. The velocity of the centroid of these stars is remarkably high. Thus 
even if we omit total velocities greater than 300 km. we find a value for the 
centroid of 74 km. This motion is almost wholly in the galactic plane. 
5. The effect of stream motion among these stars is very marked. The 
axes for which the sum of the squares of the projected velocities is a maximum 
and a minimum have longitudes of 141° and 61°, respectively, and latitudes 
of +9° and —49°. The projections of these axes upon the galactic plane are 
• \ 
• 
• \ 
• \ 
1 1 1 "1 , • \ 
■+200 
■+ 100 
-500 -400 ■ -300 -200 , / 
• • /Sv 
• r \ 
• 
• 
• 
• 
• 
• 
\. +100 +200 +300 
• \. 
• 
^100 
• 
• 
■-200 
-300 
-400 
• 
-55o 
FIG. 1. PROTECTION ON GALACTIC PLANE OF APICES OF MOTION OF 37 STARS OF HIGH 
RADL\L VELOCITY 
The vectors drawn from the origin represent the projected velocities in km per sec. 
The axes of the ellipse of intersection of the velocity-ellipsoid with the galactic plane are 
indicated by the two arrow-headed lines. 
indicated in the figure. The mean square dispersion along the major axis 
is over twice that along the minor axis. The value for the major axis is 
in close agreement with that found by Stromberg from a discussion of the 
radial velocities of 260 dwarf stars, and with that of Raymond from 559 stars 
of large proper motion. All of these investigations indicate that the galactic 
longitude of the principal vertex for the stars of high velocity is considerably 
less than that for stars in general. 
