146 
ASTRONOMY: G. STROMBERG 
Proc. N. a. S. 
shown by a study of the velocity-distribution of stars having very high 
speeds. In the diagram in figure 2 are plotted the projections in the xy plane 
of the velocities of stars having space motions larger than 100 km. /sec. 
The effect of the selection of proper motions relative to the sun instead 
of to our adopted origin is then insignificant, and we find that whatever 
the spectral types or the absolute magnitude, if the velocity of the star 
-50O -400 -30O -200 -100 Y +K)0 +200 +300 ^ 400 
*200i 1 1 ] 1 1 1 \ 1 1 1 j 1 1 1 1 1 1 1 1 1 +200 
^ I P C ) km, 
F 5' 
GJSJ 
WIS 
M Dwarf J 
-500 -400 -300 -200 -100 
FIG. 2 
► 100 + 200 +300 
Projections in the galactic plane of the velocities of stars having a speed greater 
than 100 km. per second. 
is great, there is an avoidance of the first quadrant in the xy plane. No 
star of speed higher than 100 km. /sec. is moving in this direction, but a 
large proportion of them are moving toward the third quadrant, a result 
in agreement with that found by Adams and Joy^ for stars of high radial 
velocity. 
1 Mt. Wilson Contr. No. 199, Astroph. J., Chicago, 53, 1921 (13). 
2 London, Man. Not. R. Astron. Soc, 79, 1919 (201). 
3 Mt. Wilson Contr. No. 163, Astroph. J., 49, 1919 (179). 
* Kapteyn, Address before St. Louis Exposition Congress, 1904. 
5 Schwarzschild, Gottingen Nachrichten, 1907, p. 614. A summary of the Theories is 
given in Eddington's, Stellar Movements and the Structure of the Universe, London, 1914. 
^ Hertzsprung, Astron. Nachrichten, 209, 1918. 
