apacity, Residual

When two insulated conductors are separated by a dielectric, and are discharged disruptively by being connected or nearly connected electrically, on removing the discharger it is found that a slight charge is present after a short interval. This is the residual charge. (See Charge, Residual.) Shaking or jarring the dielectric facilitates the complete discharge. This retaining of a charge is a phenomenon of the dielectric, and as such, is termed residual capacity. It varies greatly in different substances. In quartz it is one-ninth what it is in air. Iceland spar (crystalline calcite) seems to have no residual capacity. The action of shaking and jarring in facilitating a discharge indicates a mechanical stre into which the electrostatic polarization of the conductor has thrown the intervening dielectric.