Density
Density is the relationship "mass per unit volume" of a substance. The most commonly derived reading from density is specific gravity, which, though dependent on temperature and reference material, can be loosely defined as the measured density divided by the density of water. Various concentrations can be calculated from the density and specific gravity.
The MacFarlane group have an Anton Parr DMA5000 series density meter. This instrument allows measurements in the temperature range of 10-90oC.
The density machine can be booked online. Book here.