A more careful examination of the I-V characteristics of our new incandescent W cell reveals the following plot:

This data was taken using the cell from Run 2...just as it was at the end of Run 2. To help stabilize the cell temperature, the cell was placed into the calorimeter enclosure where it is immersed in water that is well coupled to the calorimeter's heat exchanger, which in turn is thermally regulated at 40° C. This test looks a lot like the first test in that, as the voltage is being increased, the current peaks and then starts falling gradually until incandescence begins at about 120V. There is no sharp decline in current as Mizuno and Ohmori observe (see their plot below). However, when the voltage is reduced, the current does stay fairly constant and the incandescence and spark-filled sheath around the cathode persists until, suddenly, at about 75 volts, all light emission stops and the current jumps back up to ~2 A/cm².

This plot shows M&O's results. Note that their current densities are considerably higher than ours. They mention using a Pt electrode. We are using a Pt anode and W cathode. We are also using a 0.1 M K₂CO₃ solution.

This plot shows how the cell temperature varied during the test described above.