Thermal Conductivity of Liquid Helium. I

Direct measurements have been made of the thermal conductivity of liquid helium over the temperature range from its normal boiling point at 4.2°K to a temperature within a few hundredths of a degree of the $\lambda$-point. The results show that the thermal conductivity decreases linearly with temperature from a value of 6.5×${10}^{-5\mathrm{}}$ cal/deg cm sec at 4.2°K to about 4.5×${10}^{-5\mathrm{}}$ cal/deg cm sec close to the $\lambda$-point. No large deviation from linearity can be detected in the heat conductivity until about 0.2 degree from the transition temperature of 2.18°K.