A NOTE ON THE HOT WIRE METHOD FOR MEASURING HEAT CAPACiTY OF GASES AT LOW PRESSURES

Abstract

A hot wire cell has been devised for measuring the specific heat of gases at low preasures, in particular of vapours below their normal boiling point. The method is based on the heat loss from an electrically heated fine wire immersed in the fluid. When the pressures are greater than about 10 torr, the heat loss is proportional to the thermal conductivity of the gas, while at pressures below 1 torr, the heat loss depend, on The specific heat. Thus, in a single experiment the thermal conductivity, the  accommodation coefficient and the specific heat of the gas are determined. Measurements on dry air at O°C and 40°C are reported.