Experiments are described which supply evidence on the manner of electrical conduction through the oxide cathode coating. In the first experiment, I–V characteristics were obtained using special diodes with embedded probes. Contrary to the Loosjes‐Vink theory, the characteristics for temperatures above 700°K are generally linear at high positive and negative potentials but curved at lower potentials. Other experiments would appear to confirm the presence of space change in the pores of the coating at temperatures above 700°K, and so support the Loosjes‐Vink theory for higher‐temperature conductivity. A modified conduction theory is put forward, and it is shown to fit in with all the known facts.