Liquid helium films. I. The thickness of the film

The thickness (d) of the helium II film and its variation with height (H) and temperature were measured by a dynamic method involving the oscillations of a meniscus in a capillary. The variation with height could be represented only approximately by the equation d = k/H$^{n}$, as the effective value of n was greater at smaller values of H. The mean value of n over a range of heights from 0$\cdot $5 to 5 cm. was 0$\cdot $14, which is appreciably smaller than the values predicted by the theories so far advanced to explain the formation of the film. The order of magnitude of k was 2 $\times $ 10$^{-6}$ cm., but it varied slightly with the nature of the surface or some other experimental factor.