  We study the motions of small solids, ranging from micron-sized dust grains
to meter-sized objects, in the vicinity of local pressure enhancements of a
gaseous nebula. Integrating numerically, we show that as a result of the
combined effect of gas drag and pressure gradients, solids tend to accumulate
at the locations where the pressure of the gas maximizes. The rate of migration
of solids varies with their sizes and densities and also with the physical
properties of the gas. The results of our numerical simulations indicate that
such migrations are most rapid for meter-sized objects. The applicability of
the results to the enhancement of the collision and coagulation of solids and
also to the growth-rate of planetesimals is discussed.
