Thermal Conductivity of Gases. III. Some Values of the Thermal Conductivities of Argon, Helium, and Nitrogen from 0 °C to 75 °C at Pressures of 1 × 105 to 2.5 × 107 Pascals.

Accurate measurements of the thermal conductivities of Ar and He agree with the theoretical value of 2.5 ϕηc _v (η = viscosity, c _v = specific heat capacity at constant volume ϕ is a number slightly greater than 1 depending upon the intermolecular potential). Measurements of the thermal conductivities of N₂ at 9.6 and 75 °C as a function of pressure up to 2.53 × 10⁷ Pa help to appraise the validity of other measurements of the thermal conductivities of dense gases. The excess conductivity of nitrogen (the additional conductivity resulting from pressure) is shown to be a function of only the density of the nitrogen from 0 to 700 °C and pressures up to 1.3 × 10⁸ Pa.