The Mass of M31 as Determined from the Motions of its Globular Clusters

An application of the virial theorem to van den Bergh's velocity measurements for the globular clusters results in a mass for M31 which is consistent with that derived by Rubin and Ford from the rotation curve. It is shown that there is a correlation between the clusters' velocity dispersion and their metallicity in the sense that metal-poor clusters have a larger velocity dispersion than metal-rich ones. Subject headings: abundances, stellar - galaxies, individual - globular clusters - stellar dynamics