A rapid method for measuring the saturated vapor pressure in liquids

A method for rapid determination of the saturated vapor pressure of a liquid phase is described. The method makes use of a capillary sealed at one end and partly filled with a liquid whose saturated vapor pressure is to be determined. Al the open end of the capillary, the liquid is brought in contact with another liquid (both liquids are mutually soluble); the interdiffusion of the two liquids causes the liquid capillary column to change its length. Measuring the change in the liquid column with an optical microscope makes it possible to determine the saturated vapor pressure of the first liquid.