Ampère Meter.—An instrument used for measuring strength of current.
Anode.—The positive electrode or pole of a decomposing cell, the wire or plate connected to the copper or other negative element of a battery. In electro-plating, it is usually the soluble pole of the metal to be deposited. (v. Cathode.)
Arc.—The air space in which the electric light forms.
Armature.—The keeper of a magnet: the part which closes the magnetic lines of the field-magnet, or the rotary part.
Battery.—A combination of two or more voltaic cells coupled together.
B. A.—British Association.
Block Station.—A central-station for the supply of continuous buildings.
Board of Trade Unit.—One thousand watt hours equals 10 ampères at 100 volts per hour, or 1·35 HP. working for one hour.
Bobbin.—A coil of wire, or a number of such coils, generally so mounted that they can be rapidly revolved.
Bridge (Wheatstone’s).—An apparatus for measuring resistances by balancing the unknown resistance against one known and capable of adjustment.