Measurement of the densities of liquids and gases under pressure using magnetic levitation of a standard sample

A simple method is proposed for measuring the pressure dependence of the density of gases and liquids in a wide temperature range. The method is based on the principle of free suspension of a standard paramagnetic sample in a nonuniform magnetic field, when the magnetic force compensates the weight of the sample, taking account of the hydrostatic support of the medium. As an example of the application of the method, the density of helium gas up to pressure similar to2.5 kbar at temperatures 20.4 and 77.3 K is determined. (C) 2002 American Institute of Physics.