An apparatus for accurate measurement of liquid and vapour densities on the saturation line, up to the critical temperature

The distinguishing feature of the equipment is a magnetically levitated Archimedian bob. The silica bob with the sample is contained in a sealed glass cell which is suspended from an automatic balance. Different types of cell are described for liquid and vapour density measurement. Also included in the equipment is a well-tried liquid density apparatus which employs a magnetically controlled float and from which the levitated-bob method was developed. Results are given for density measurements to near-critical temperatures of samples of propan-2-ol (vapour only) and benzene. The vapour measurements are prejudiced by slowness of equilibration between liquid and vapour at lower temperatures, and by an unidentified factor producing low results. Nevertheless the general self-consistency and reproducibility of the results indicates the effectiveness of the method.