The sublimation temperature of carbon dioxide

The technique of realizing the sublimation temperature of carbon dioxide at standard atmospheric pressure is described and its value on the International Practical Scale of Temperature (I.P.S.T.) is found to be - 78?5103 ? 0?003?C, and on the thermodynamic Celsius scale - 78?475 ? 0?005?C (194?675?K). It is concluded that it is a suitable fixed point, in addition to the boiling point of oxygen and the triple point of water, for the realization of a practical scale over the temperature range from - 182?97?C to 0?C. The vapour-pressure-temperature relation is deduced for a small range of pressures near to one standard atmosphere. Comparisons are made with previous determinations.