On the Form of the Distribution Law of Stellar Velocities.

Legends for Fig. 2 IV. so Persei. This star is not known to be a variable. The observations are of moderate accuracy, being normal places from one-prism observations by Jordan at Allegheny. It is a star of very complex and erratic behavior. Cannon5 (observations not shown) postulated a secondary of one-half the main period, but it is impossible to satisfy Jordan's data in this manner. V. 62 Cygni.6 Not known to be a variable. The observations are of moderate accuracy, being normal places from one-prism observations by Cannon at Ottawa, with the inclusion of four Lick three-prism values. The observations are grouped almost precisely as would be expected were there a blend effect, but such an effect was searched for without result. Cannon's primary has vn eccentricity of 0.18, and he introduces a secondary of one-third the main period. I cannot satisfy these observations with a single hump, as in the cases given before. It is of interest to see that an entirely different orbit from that of Cannon shows some measure of agreement. More observations are urgently needed on this star, particularly just after maximum velocity of recession, to decide on the character and reality of its deviations. VI. ,B Cephei.7 A Cepheid variable of unusually short period 0d.19 Crump's observations with the Detroit Observatory one-prism are normal places and of rather high accuracy. My curve does not satisfy these places quite so well as does his orbit, which postulates a secondary of one-third the main period, with a semi-amplitude of but 1.25 km. One purpose of this paper will be fulfilled if those possessing instruments of adequate power will accumulate many more observations of the light and velocity curves of the Cepheids; only with such assistance will it ever be possible to solve the many puzzles which they present. 1 Campbell, Astrophys. J., 13, 1900 (90). 2 Curtiss, Lick Obs. Bull.,.3, 1904 (62). 3Plaskett, Publ. Dom. Obs., 2, No. 2, 1915. 4Jordan, Publ. Allegh. Obs., 3, 1913 (31). 5Cannon, J. R. A. S. Canada, 4, 1910 (195). 6 Cannon, Astrophys. J., 47, 1918 (193). 7 Cramp, Pubi. Detroit Obs., 2, 1915 (144). 8 Dncan, Lick Obs. Bull., 5, 1908 (82).