The freezing point of zinc as a primary point of the International Temperature Scale

The technique is described of achieving the highest accuracy of measurement with platinum-resistance thermometers at the freezing point of zinc and the boiling point of sulphur. The two points are compared in a series of measurements and it is found that the zinc point is some three or four times more reproducible than the sulphur point. It is concluded that the substitution of the zinc point for the sulphur point as a primary fixed point of the International Temperature Scale would lead to a greater precision in the definition of the scale. The value of the freezing point of zinc is found to be 419∙5055 ± 0∙002°C.