Electron loading in electrostatic generator accelerator tubes due to the passage of pulses of current of millisecond duration has been investigated. The characteristics of pulse discharge conduction are described and a theory of its origin proposed. This theory envisages an exchange of positive and negative ions of hydrogen between the electrodes in a regenerative reaction, the source of the ions being a chemi-sorbed layer of hydro-carbon on the electrode surfaces. Measurements of the secondary emission coefficients and other experimental evidence appear to be consistent with such a hypothesis. Methods of suppression of this pulse discharge conduction are discussed.