Thermomagnetic Force in Polyatomic Gases

A force has been observed on a small thin disk which is immersed in a polyatomic gas when a thermal gradient is established and when a magnetic field is applied. This thermomagnetic force is normal to the surface of the disk and is an even function of the magnetic field. Measurements are reported of this force effect as a function of magnetic field and pressure for ${\mathrm{O}}_2$ and NO in the temperature range 30-35°C. These new results are compared to a related thermomagnetic effect on the thermal conductivity of a polyatomic gas (Senftleben-Beenakker effect).