572. How does the equilibrium of electricity become disturbed?
By changes in the condition of matter. As electricity resides in all substances, and is, perhaps, an essential ingredient in their condition, so every change in the state of matter—whether from heat to cold, or from cold to heat; from a state of rest to that of motion; from the solid to the liquid, or the æriform condition, or vice versa; or whether substances combine chemically and produce new compounds—in every change the electrical equilibrium is disturbed; and, in proportion to the degree of disturbance, is the force exerted by electricity to resume its balance in the scale of nature.
573. How does electricity seek to regain equilibrium?
By passing through substances that are favourable to its diffusion; therefore they are called conducting or non-conducting bodies, according as they favour or oppose the transmission of the electrical current.
574. What substances are conductors of electricity?
Metals, charcoal, animal fluids, water, vegetable bodies, animal bodies, flame, smoke, vapour, &c.
575. What substances are non-conductors?
Rust, oils, phosphorous, lime, chalk, caoutchouc, gutta percha, camphor, marble, porcelain, dry gases and air, feathers, hair, wool, silk, glass, transparent stones, vitrefactions, wax, amber, &c. These bodies are also called insulators. Some of these substances, as chalk, feathers, hair, wool, silk, &c., though non-conductors when dry, become conductors when wetted.
Insulating—preventing from escaping.
576. Why are amber and wax classed among the non-conductors, when they have been pointed out as electrics, and used to illustrate electrical force?