http://farside.ph.utexas.edu/teachin...es/node44.html
"However, in experiments in which a capacitor is submerged in a
dielectric liquid the force per unit area exerted by one plate on
another is observed to decrease... (...) This apparent paradox can be
explained by taking into account the difference in liquid pressure in
the field filled space between the plates and the field free region
outside the capacitor."

The pressure difference will constantly pump water through a small
hole punched in one of the plates, in violation of the second law of
thermodynamics. The hole could be drilled at the level of points 3 and
5 in FIG. 1 below:

http://pages.csam.montclair.edu/~yec...MagnFluids.pdf
"FIG. 1. Two charged condenser plates partly immersed in a dielectric
liquid. (...) FIG. 2. The hydrostatic pressure variation from point 1
to point 5 in Fig. 1."

Pentcho Valev