The surface tension of mercury and the adsorption of some hydrocarbons on mercury.

The surface tension of mercury is within 0.2% of 485.4 dynes cm-1 at 25°C. and 487.3 dynes em-1at 16.5°C. These values are in agreement with the most reliable work to date (Kemball (3) ). It is not necessary , as all workers have insisted, to \clean\" the glass vessel in which the surface tension is measured. The normal saturated aliphatic hydrocarbons give almost the same lowering of the surface tension at the same relative pressures of vapour i.e. the decrease In vapour pressure on ascending the hydrocarbon series is approximately balanced by an increase in the intensity of adsorption. The results are analysed on the basis of two surface equations of state the Volmer equation (a two dimensional analogue of Van der Waalls equation with the repulsive term predominating) and the Virial - equation in two dimensions with the correction term related to the forces between the molecules. From these two viewpoints the hydrocarbon molecules appear to be relatively curled up on the surface with their electron envelopes highly distorted."