The radiation of energy from a thoriated tungsten filament and the absorption of the energy radiated from the surrounding bulb have been measured by a method which eliminates difficulties arising from cooling effects of the leads. For a filament at a uniform temperature TF in a bulb at temperature TB the net radiation W in watts cm-2 is the difference between the outgoing radiation WR and the absorbed radiation WA. For values of TF from 225° to 580°K and TB from 77° to 473°K log WR=83.7105-100+5.332 log TF, log WA=83.7105-100+4.462 log TB+0.87 log TF. The resistivity R0 in this same range is given by log R0=91.7123-100+1.23 log TF. The characteristics, current, voltage, resistance, and energy radiated as functions of temperature are tabulated.
IRVING LANGMUIR and J. BRADSHAW TAYLOR, "Radiation and Absorption of Energy by Tungsten Filaments at Low Temperatures," J. Opt. Soc. Am. 25, 321-323 (1935)