The use of the iron core renders it possible to produce a high inductive effect with a low resistance coil.
Each coil is attached to a shaft by a bell crank arrangement, and to these shafts there is secured a system of levers similar to that at the transmitter carrying the receiving pencil at the junction.
The coil is encased with firebricks and brickwork, and the smoke from the fire is carried, off by a flue in the ordinary s " way.
In the ordinary methods, a differentially wound receiving instrument was used, one coil being connected with the cable Company and the various Atlantic cables, are worked duplex on method of duplexing a cable was described by Lord Muirhead's plan.
Ance coil of some 2000 turns of insulated copper wire, enclosed in a laminated iron circuit, and connected at intervals to a number of terminals so that equal increments of inductance may be obtained.