  In this work we concentrate on an experimental validation of the Lifshitz
theory for van der Waals and Casimir forces in gold-alcohol-glass systems. From
this theory weak dispersive forces are predicted when the dielectric properties
of the intervening medium become comparable to one of the interacting surfaces.
Using inverse colloid probe atomic force microscopy dispersive forces were
measured occasionally and under controlled conditions by addition of salt to
screen the electrostatic double layer force if present. The dispersive force
was found to be attractive, and an order of magnitude weaker than that in air.
Although the theoretical description of the forces becomes less precise for
these systems even with full knowledge of the dielectric properties, we find
still our results in reasonable agreement with Lifshitz theory.
