A slightly ionized gas was formed in the wake of a detonation wave in a shock tube by seeding with a potassium salt. Wire electrodes were placed with axes normal to the shock‐tube axis and separated by a variable distance along the tube axis. The heating of each electrode was measured by determining the rate of change of electrical resistance of the electrode. Electrode heating in excess of that due to aerodynamic heat transfer was only observable in the range of 102to 103A/cm2and was found to be proportional to the current. The excess heating rate divided by the total current was measured to be 4.9 V for the anode and 3.2 V for the cathode. By varying the spacing of the electrodes, it was found that the gas resistance could be accounted for by the geometric effects alone in combination with the gas conductivity as measured by Basu for this mixture.