1297.  The direct inductive force, which may be conceived to be exerted in lines between the two limiting and charged conducting surfaces, is accompanied by a lateral or transverse force equivalent to a dilatation or repulsion of these representative lines (1224.); or the attractive force which exists amongst the particles of the dielectric in the direction of the induction is accompanied by a repulsive or a diverging force in the transverse direction (1304.).

1298.  Induction appears to consist in a certain polarized state of the particles, into which they are thrown by the electrified body sustaining the action, the particles assuming positive and negative points or parts, which are symmetrically arranged with respect to each other and the inducting surfaces or particles[A].  The state must be a forced one, for it is originated and sustained only by force, and sinks to the normal or quiescent state when that force is removed.  It can be continued only in insulators by the same portion of electricity, because they only can retain this state of the particles (1304).

[A] The theory of induction which I am stating does not pretend to decide whether electricity be a fluid or fluids, or a mere power or condition of recognized matter.  That is a question which I may be induced to consider in the next or following series of these researches.

1299.  The principle of induction is of the utmost generality in electric action.  It constitutes charge in every ordinary case, and probably in every case; it appears to be the cause of all excitement, and to precede every current.  The degree to which the particles are affected in this their forced state, before discharge of one kind or another supervenes, appears to constitute what we call intensity.

1300.  When a Leyden jar is charged, the particles of the glass are forced into this polarized and constrained condition by the electricity of the charging apparatus. Discharge is the return of these particles to their natural state from their state of tension, whenever the two electric forces are allowed to be disposed of in some other direction.

1301.  All charge of conductors is on their surface, because being essentially inductive, it is there only that the medium capable of sustaining the necessary inductive state begins.  If the conductors are hollow and contain air or any other dielectric, still no charge can appear upon that internal surface, because the dielectric there cannot assume the polarized state throughout, in consequence of the opposing actions in different directions.