  We compare the lateral retention forces on sessile drops (which are drops
that are placed on top of a solid surface), pendant drops (which are drops that
are placed on the underside of the surface), and inverted sessile drops (which
are drops that are first placed on top and then on the underside of the surface
by flipping the surface). We have found experimentally that the retention force
on a truly pendant drop is always smaller than that on a sessile drop. However,
the retention force on an inverted sessile drop is comparable to, and usually
larger than, that on a sessile drop. Thus, the retention force on a drop
depends not only on whether it is placed on top or on bottom of a surface, but
also on the history of drop deposition, since such history affects the width,
the shape and the contact angles of the drop.
