  The nonsymmetric gravitational theory predicts an acceleration law that
modifies the Newtonian law of attraction between particles. For weak fields a
fit to the flat rotation curves of galaxies is obtained in terms of the mass
(mass-to-light ratio M/L) of galaxies. The fits assume that the galaxies are
not dominated by exotic dark matter. The equations of motion for test particles
reduce for weak gravitational fields to the GR equations of motion and the
predictions for the solar system and the binary pulsar PSR 1913+16 agree with
the observations. The gravitational lensing of clusters of galaxies can be
explained without exotic dark matter.
