It is because they are non-conductors that they have displayed, under excitement, the attractive force shown in respect to the particles of matter which were drawn towards their substances. If a bar of iron were excited, instead of a stick of wax, electricity would be equally developed; but the iron, being a good conductor, would pass the electricity to the hand of the operator as fast as it accumulated, and the equilibrium would be undisturbed.
"Yea, he sent out his arrows, and scattered them; and he shot out lightnings and discomfited them."—Psalm xviii.
577. What is the effect when electricity, in considerable force, seeks its equilibrium, but meets with insulating bodies?
The result is a violent action in which, intense heat and light are developed, and in the evolution of which the electric force becomes expended.
578. What is the cause of electric sparks?
The electric force, passing through a conducting body to find its equilibrium, is checked in its course by an insulator, and emits a spark.
579. What produces the electric light?
Currents of electricity pass towards each other along wires at the ends of which two charcoal points are placed. As long as the charcoal points remain in contact, the electric communication is complete, and no light is emitted, but, when they are drawn apart, intense heat and light are evolved.