The Temperature Scales of Columbium, Thorium, Rhodium and Molybdenum at 0.667μ

To establish temperature scales for columbium, thorium, rhodium and molybdenum spectral emissivities were measured for these metals at λ=0.667μ. The Mendenhall V wedge was used for columbium and rolled cylinders were used for the other metals. Rolled cylinders were more satisfactory for measuring emissivities than specimens in other forms. Rigorous heat treatment was found necessary for accurate results. Emissivities for all four metals were constant with temperatures. Results are: Emissivity λ=0.667μ Temperature range covered Columbium 0.374 1300°-2200°K Thorium .380 1300°-1700° Rhodium .242 1300°-2000° Molybdenum .382 1300°-2100°