In a motor the brushes are set backwards from their normal position, or in a position towards the direction of armature rotation or given a negative lead instead of a positive one, such as is given to dynamo brushes.

The platinum wires passing through the glass of an incandescent lamp-chamber, to effect the connection of the carbon filament with the wires of the circuit.

The tips of pole pieces in a dynamo, which extend in the direction of movement of the armature.

A metal; one of the elements; symbol Pb. Atomic weight, 207; equivalent, 103-1/2; valency, 2. Lead may also be a tetrad, when its equivalent is 51.75. The following data are at 0º C. (32º F.) with compressed metal: Relative Resistance, (Silver = l)     13.05 Specific Resistance,                  19.63   microhms. Resistance of a wire, (a) 1 ft. [...]

This rather crude name is given by Emtage to a law expressing the relation of direction of current in a circuit to the positive direction of the axis of a magnet acted on by such current. It is thus expressed: A right-handed screw placed along the axis of the magnet and turned in the direction [...]

A law of thermo-electricity. The electro-motive force due to a given difference of temperature between the opposite junctions of the metals is equal to the sum of the electro-motive forces produced by fractional differences of temperature, whose sum is equal to the given difference and whose sum exactly fills the given range of temperature.

When force is exercised through space from a point, its intensity varies inversely with the square of the distance. Thus the intensity of light radiated by a luminous point at twice a given distance therefrom is of one-fourth the intensity it had at the distance in question. Gravitation, electric and magnetic attraction and repulsion and [...]

A law of thermo-electricity. The electro-motive force between any two metals is equal to the sum of electro-motive forces between each of the two metals and any intermediate metal in the thermo-electric series, or the electro-motive force between any two metals is equal to the sum of the electromotive forces between all the intermediate ones [...]

The bound charge of static electricity. (See Charge, Bound.)

A receptacle for an incandescent lamp; the lamp being inserted the necessary connections with the two leads are automatically made in most sockets. The lamps may be screwed or simply thrust into the socket and different ones are constructed for different types of lamps. A key for turning the current on and off is often [...]