Thermomolecular Pressure Ratios forHe3andHe4

Abstract
Thermomolecular pressure ratios of He3 have been measured for a tube extending from room temperature to a bulb at 2°K. The results agree within experimental accuracy with He4 ratios calculated from the Weber-Schmidt equation. Detailed calculations from this equation are given. Limitations of the equation due to large deviations from ideal viscosity behavior in the liquid helium range are discussed.