The enthalpy of liquid mercury was measured from 0° to 450° C by the " drop" method .These and other precise published data were used to calculate a number of the rmodynamic properties of liquid and gaseous mercury at the vapor pressures from the triple point , -38.88°, to + 500° C. The entropy calculated from data on the vapor and liq uid was compared with that derived from published low-temperature heat-capacity data for the solid .The calculated values of vapor pressure, also using data on the vapo r and liquid, were fo und to agree over a wide temperature range with certain published experimental values when independently derived gas-imperfection and published temperature-scal e corrections were applied.

Using an improved ice calorimeter and furnace, t he e nthalpy changes of two samples of pure sodium have been accurately meas ured by a drop m ethod at a number of temperatures between 0° and 900° C. Equations are derived to fit t he data, and values of enthalpy and entropy, based on zero values at 0° C, as well as the heat capacity are tabulated for both the solid and liquid. Sources of significant experime ntal error are examined critically, and some theoretical implications of t he results are discussed qualitatively.

Precise mcasurements of the heat capacity of so lid and liquid n-heptane from 20 0 to 523 0 K arc described. An adiabatic calorimeter, with which were determined also the triple point and the heat of fusion, was used from 20 0 to 370 0 I\:, whereas a drop method was used with a Bunsen icc calorimeter from 273 0 to 523 0 K. These two series of heat-capacity measurements and three other se ries of independent values show a maximum difference of approximately 0.25 percent in the range 50 0 to 370 0 K. Besides the heat capacity, tIl(' enthalpy, entropy, and Gibbs free enerp:y of the solid and liquid at saturation pressures from 0 0 to 520 0 K are derived and tabulated. The same properties of the ideal gas from 298 0 to 470 0 K also arc derived by making use of publishcd precise measurements of gaseous heat capacity, heat of vaporization, and the normal boiling point. Interconsistency in the values of t he various thermal properties is shown by the fact that the vapor pressures calculated from these values ap:rce with those precisely measured by other investigators bet\\"een 200 0 and 372 0 K to \\'ithin ± 0.1 percent.

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