I. Electrostatic Capacity of Glass.—II. In 1877 I had the honour of presenting to the Royal Society the results of some determinations of the specific inductive capacity of glass, the results being obtained with comparatively low electromotive forces and periods of charge and discharge of sensible duration. In 1878 Mr. Gordon presented to the Royal Society results of experiments, some of them upon precisely similar glasses, by a quite different method, with much greater electromotive forces and with very short times of charge and discharge. Mr. Gordon’s results and my own are compared in the following table:- It is quite clear that such enormous differences cannot be due to mere errors of observation; they must arise from a radical defect in one method or the other, or from some property of the material under investigation. I have now repeated my own experiments with greater battery power, and with a new key for effecting the connexions of the condensers, and have obtained substantially the same results as before.