Determination of the Thermodynamic Temperatures of the Freezing Points of Silver and Gold by Near-Infrared Pyrometry

The thermodynamic temperatures of the freezing points of silver and gold have been measured relative to the aluminium point with a photoelectric pyrometer of effective wavelength about 974 nm. The values obtained are 1234.927 K ± 0.018 K and 1337.330 K ± 0.022 K respectively. These results are based on the value of -64.3 mK for T-T 68 at 730 K, recommended by the working group IV of the CCT in Dec. 1988 to take into account the most recent results of the gas thermometry of Edsinger and Schooley. The overall uncertainties are given at 68.3% confidence limits.