  We offer a brief description of the bulk-motion Comptonization (BMC) model
for accretion onto black holes, illustrated by its application to observational
data for LMC X-1, and Nova Muscae 1991. We then extract some physical
parameters of these systems from observables (within the context of the BMC
model}, drawing from results on GRO J1655-40, for which we presented extensive
analysis previously. We derive estimates of the mass, (16 +/- 1) solar masses
and mass accretion rate in the disk in Eddington units around 2 for LMC X-1,
and (24 +/- 1)d_{5.5} and the disk mass acretion rate around 3 for Nova Muscae
1991 [where d_{5.5} stands for the distance in 5.5 kpc units]. Differences
between these estimates and previous estimates based on dynamical studies are
discussed. It is further shown that the disk inner radius increases with the
high-to-low state transition in Nova Muscae 1991. Specifically, our analysis
suggests that the inner-disk radius increases to 17 Scwarzschild radii as the
transition to the low-hard state occurs.
