He II Film Profile and Relative Importance of Height and Surface Pressure

The thickness $d$ of the He II film at 1.40°K vs height $h$ to 40 cm has been measured by an optical method. Results agree better with an expression of the form $d=k{h}^{-\frac{1}{3}}$ than with $d=k{h}^{-\frac{1}{2}}$ or $h={\left(\frac{a}{d}\right)}^3+{\left(\frac{b}{d}\right)}^2$. Evidence was obtained suggesting that the contour of the film cannot be accounted for by considering it to be an adsorbed film subjected to a varying pressure. The pressure would decrease with height due to gravitational effects in a vertical gas column.