On the sparking potentials of discharge tubes containing carefully purified electrodes

The present paper describes the results obtained in a continuation of some earlier work carried out on the electrode surface phenomena of discharge tubes in their relation to the sparking potential function. The discharge tubes used previously contained a filling-gas of neon-helium mixture, and the electrodes were of nickel or iron. It was found that there was an increase of the sparking potential with “ flashing ” or discharge. This increase was termed “polarisation.” In certain cases relatively large polarisations were observed. Polarisation could be reduced or eliminated in many cases by passing a discharge in the reverse direction through a polarised tube,or by resting it for a few hours.