In the present Part an attempt is made to determine the nature of the dissociative action which accompanies the passage of a current through a barium-strontium-oxide matrix at 1 020°K. Two identical oxide systems operating at a common temperature and passing the same quantity of electricity but at different rates might be expected to suffer the same mass of oxide dissociation. Experiment shows, however, that such is not necessarily the case and that dissociation mass is determined by rate of application of electricity rather than by the total quantity of electricity.The products of dissociation are shown to be in ionic form, and experimental arrangements are made for the separate collection of the ions in chemical form on a relatively massive scale.A working hypothesis is offered in explanation of the experimental observations.