We derive an expression for the temporal development of circular holes
formed spontaneously in dewetting liquid films. Our formula is shown
to interpolate between the known limiting cases of perfect sticking (p
urely viscous dissipation) and full slippage of the film on the substr
ate. Good agreement between experiment and theory is found. By fitting
the theroetical curves to the data, we can derive the relative import
ance of slip in the dewetting process.