ASTRONOMY: H. RAYMOND 
489 
In regard to these results the following points seem especially worth 
noting: 
1. All groups show markedly unequal motions in three principal 
directions. In all groups the direction of greatest motion, or axis of 
preference, Hes near the plane of the galaxy not far from its intersection 
with the equator, the axis of avoidance is nearly perpendicular to the 
galaxy. 
Using radial velocities Gyllenberg^ finds much the same axis of pref- 
erence, but the other two axes practically interchanged. So do Edding- 
ton and Hartley® for later types, but their results for early types agree 
better with table 1. Are these differences real, in the sense of being 
typical of what may be expected whenever radial velocities and proper- 
motions are compared? If so, what peculiarity of distribution or of 
motions in space, out of the many that might easily be suggested, lies 
back of it? Here is a subject well worth investigation. 
2. The separation of the poles of preference into two groups corre- 
sponding respectively to ^early' and 4ate' types,^ is confirmed. There 
seems to be some evidence of progression of the same character within 
each of the two groups of types, as if with advance of type the 6-hour 
vertex moved northward. With advance of t3^e there is an increase 
of stellar as compared with solar motion; that in the preferred direction, 
however, increasing less than the other two components. 
3. The apices of solar motion show the division into two groups al- 
ready found by several investigators; A and F having apices in smaller 
R. A. and Decl. than K, M, and X. B seems to resemble the latter 
group. G is anomalous. 
These results agree rather closely with those found by L. Boss by 
Airy's method,^^' and by the writer by Schwarzschild's method,® all 
three being based upon practically the same material. This agreement 
will be found to extend even to details. 
4. The distribution of stars of type B is so peculiar that to weight 
the material according to area covered would have been unfair. The 
integrations which give equations (E) can be made over zones parallel 
to the galaxy, and the resulting relations used to correct each zone for 
perspective separately, the material then being combined with weights 
proportional to the number of stars. The results in the tables were 
thus found ; a check solution by the ordinary method gave for the vertex 
(122°,-36°). 
The vertex of preferential motion is near the antapex of solar motion. 
This may in part be a manifestation of the tendency, noted above, for 
the earlier types to have more southerly vertices. In part it is due to 
