Velocity of Propagation of Electrostatic Force

Abstract

In making the statement quoted, I had fully taken into account all such considerations as those referred to in Prof. Leahy's letter. The rigidity of the solid absolutely prevents any phenomenon, analogous to the attractions by rubbed amber or lodestone, from being exhibited in an elastic solid. No such barrier exists if the elastic medium be fluid; and § § 733–740 of article¹ xli. of my “Electrostatics and Magnetism” contain conclusions of hydrokinetic theory regarding mutual forces between movable tubes or rings with cyclic motion of an incompressible liquid through them, showing magnitudes identical with, but directions exactly opposite to, those of the forces in electro-magnetic analogues consisting of movable conductors conveying electric currents. The remainder of that article contains remarks on Guthrie's interesting paper² “On Approach caused by Vibration,” and “On the Attractions and Repulsions due to Vibration, observed by Guthrie and Shellbach,” from which the following (§ 744), being an extract from a report, in the North British Daily Mail, of an address by myself to the Philosophical Society of Glasgow on December 15, 1870, may possibly be read with interest in connection with Prof. Leahy's letter:—