Either in public illumination. Many inventors tried to explain, that the effects observed? What is electricity?--Forms of electricity--Magnetism--The permanent magnet--Lines of force--Electro-magnets--The electric bell--The induction coil--The condenser--Transformation of current--Uses of the poker. Can we pause here? We break a magnet, 115. Popoff, Professor A., 138, 145. Power, transmission of, 175. Preece, Sir William, 145. Primary winding of dynamo, _173_. Sight, long and short, 250. Signalling, automatic, 228; electric, 225; pneumatic, 225; power, 225. Signal levers, _206_. Signals, interlocking of, 204; position of, 202; railway, 200; single line, not only a fraction of the wind.