  Although the free-fall three-body problem have been investigated for more
than one century, however, only four collisionless periodic orbits have been
found. In this paper, we report 234 collisionless periodic orbits of the
free-fall three-body system with some mass ratios, including three known
collisionless periodic orbits. Thus, 231 collisionless free-fall periodic
orbits among them are entirely new. In theory, we can gain periodic orbits of
the free-fall three-body system in arbitrary ratio of mass. Besides, it is
found that, for a given ratio of masses of two bodies, there exists a
generalized Kepler's third law for the periodic three-body system. All of these
would enrich our knowledge and deepen our understanding about the famous
three-body problem as a whole.
