  The density and velocity fields as extracted from the Abell/ACO clusters are
compared to the corresponding fields recovered by the POTENT method from the
Mark~III peculiar velocities of galaxies. In order to minimize non-linear
effects and to deal with ill-sampled regions we smooth both fields using a
Gaussian window with radii ranging between $12 - 20\hmpc$. The density and
velocity fields within $70\hmpc$ exhibit similarities, qualitatively consistent
with gravitational instability theory and a linear biasing relation between
clusters and mass. The random and systematic errors are evaluated with the help
of mock catalogs. Quantitative comparisons within a volume containing
$\sim\!12$ independent samples yield
$\betac\equiv\Omega^{0.6}/b_c=0.22\pm0.08$, where $b_c$ is the cluster biasing
parameter at $15\hmpc$. If $b_c \sim 4.5$, as indicated by the cluster
correlation function, our result is consistent with $\Omega \sim 1$.
