A New Determination of the Melting Point of Palladium

The melting point of palladium was determined by measuring with an optical P3^rometer the ratio of brightness of the red light (X= 0.6528m) emitted by black bodies at the melting points of palladium and gold, respectively. The crucible method was shown to be more reliable than the wire method. Especial attention was given to the purity of the metals. The result obtained by the crucible method, when substituted in Wien's or Planck's equation, gives the melting point of palladium as 1,556.6° C. with an uncertainty of 1°. In the computations C3 was taken as 1.432 cm deg. and the melting point of gold as 1,063° C. The average of the present result, and those of six previous determinations, is 1,553° ±0.7°. Estimating the uncertainty in C2 as 0.002 and in the melting point of gold as 0.5°, it is concluded that the uncertainty in the value of the melting point of palladium on the centigrade thermodynamic scale is approximately 2°.