Method of the heated filament (incorporating a null section) for use in corrosive media, and determination of the thermal conductivity of sodium vapor

A new version of the heated-filament method of determining thermal conductivities is described; it employs no insulating materials. The currents of the working filament and sheath in the measuring cell are separated by using a null section. Experimental data are presented for the thermal conductivity of sodium vapor in the range $900$–$1100$ degree K.