The Encyclopedia Americana (1920)/Dielectric

DIELECTRIC, a name applied by Faraday to any medium through or across which electrostatic induction can take place. (See ../Induction, Electrostatic). Solids, liquids and gases possess this property of transmission, though in differing degrees, and their dielectric value, or specific inductive capacity, is measured by the ratio of the capacity of a condenser in which each may form the insulator, to the capacity of the same condenser with a vacuum as insulator.