Ε½
. Measurements of isochoric heat capacities C for pure water and
as a function of temperature along the different isochores and on the coexistence curves are reported. The measurements cover the range in temperature from 299 K to 536 K at Ε½ . xKNO s 0.0017969. For pure water, measurements have been performed in the 3 . y3
. y3 temperature range 321 K to 576 K at densities from 712 kg m to 990 kg m . The Ε½ experiments were performed at six isochores: 793.85, 816.22, 883.96, 932.70, 978.20, and . y3 . Ε½ . Ε½ 1002.40 kg m for H O q KNO , and seven isochores: 712.66, 799.22, 864.83, 916.31, 2 3
. 938.79, 956.76, and 989.58 for pure water. The measurements were taken in a hightemperature and high-pressure adiabatic nearly constant-volume calorimeter. Uncertainties of the isochoric heat capacity measurements are estimated to be less than 1.5 per cent. Oneand two-phase heat capacities, temperatures, and densities at saturation were obtained by the method using quasi-static thermograms. The isochoric heat capacities C are described
with an equation of state originally proposed for NaCl by Pitzer and co-workers, and the deviations in fit are "2 per cent or less.