Thermal conductivity of methane in the critical region

A set of very accurate experimental data are presented for the thermal conductivity of methane in the critical region. Some of the values are significantly higher than values from transient hot-wire experiments reported in the literature. The thermal-conductivity data along the critical isochore approach the critical temperature to within 0.021 K which is much closer than achieved by previous investigators. The experimental enhancement of the thermal conductivity of methane in the near vicinity of the critical point is not consistent with the behavior deduced from the mode-coupling theory for the effects of the critical fluctuations on the thermal conductivity if only the experimental uncertainty is considered. However, consistency prevails of one take also into account the uncertainty of the theoretically calculated thermal-conductivity values caused by uncertainties in the cp values of methane close to the critical point.