Con-duct′or.
1. (Electricity.) A term applied to a body capable of transmitting an electric current. Strictly speaking, all bodies are conductors of electricity, but those of relatively very small conductivity are known as non-conductors; for instance:—
The conductivity of copper being estimated at 40,000,000,
That of water is as 1.
Becquerel's table is as follows:—
| Pure copper wire | 100 |
| Gold | 93.6 |
| Silver | 73.6 |
| Zinc | 28.5 |
| Platinum | 16.4 |
| Iron | 15.5 |
| Lead | 8.3 |
In practice: A prime conductor collects and transmits the frictional electricity of the electrical machine. It was introduced by Bose in 1741.
A lightning-conductor, for conducting the static or tension electricity of the atmosphere harmlessly to the earth. It consists of a wire, rod, or slip of metal from the top of a house, tower, steeple, or mast, to the ground, or, better still, a ground-plate or system of buried iron pipes.
Gray and Wheler, in 1720-1736, made experiments to ascertain the distance through which electric force could be transmitted, using insulated metals.
Gray, in 1729, discovered the properties of electric conductors. “He found that the attraction and repulsion which appear in electric bodies are exhibited also by other bodies in contact with the electric.” —Whewell.
Dr. Watson, in 1747, passed transmitted electricity [610] through 2,800 feet of wire and 8,000 feet of water, using the earth circuit.
Benjamin Franklin, in 1748, performed his experiments on the banks of the Schuylkill, “concluded by a picnic, when spirits were fired by an electric spark sent through the river, and a turkey was killed by the electric shock, and roasted by the electric jack, before a fire kindled by the electrified bottle.” The latter was the Leyden jar, the invention of Muschenbroek and Kleist, three years previous.
Franklin flew his kite in Philadelphia in 1752, and proved the substantial identity of lightning and frictional electricity. He then invented the lightning-rod for the harmless passage of the electricity.
D'Alibard erected a lightning-rod in the same year.
Richmann of St. Petersburg, the following year, in repeating Franklin's experiment, was killed by a stroke of lightning.
Charles Marshall, in 1753, proposed insulated wires, suspended by poles, as electrical conductors for transmitting messages.
Lesarge, in 1774, used twenty-four electrized wires and a pith-ball electrometer as a mode of signaling. Lomond, in 1787, used one wire and a pith-ball.
Reizen, in 1794, had twenty-six line wires and letters in tin-foil which were rendered visible by electricity.
Cavallo, in 1795, had one wire, and talked by sparks. He had an explosion of gas for an alarm.
2. (Surgical.) A grooved staff for directing a penetrating instrument in surgical operations; such as the forceps in extracting balls; lithontriptic instruments, etc.
