It was shown in part I of the present series of researches that a gold or silver surface becomes charged when heated in vacuo or in contact with various gases, and that the charge on the surface depends, in the main, upon the temperature and the nature of the gas, and also to some extent upon the previous history of heating of the surface; but is independent, within wide limits, of the gas pressure. In view of the close bearing which these results undoubtedly heave upon the nature and mechanism of heterogeneous catalysis, the investigation is being extended to an examination of the electrical conditions of a variety of other surfaces. In what follows an account is given of the experimental results obtained with a nickel surface at temperatures up to 850° C. The apparatus previously described and illustrated in Part I was employed in all experiments to be described below, a rolled-up nicked 20 S. W. G. Sheet, 7 cm. by 12 cm., being suspended in the vertical quartz vessel by means of a narrow nickel tape cut from the sheet itself. The sheet had been previously washed with petroleum ether, no attempt having been made to remove the thin oxide film. The surface charge was measured by means of a Lindemann electrometer. The experimental procedure was essentially that followed and described in Part I.