Galvanometer

TC232

A Telegraph Lineman's Galvanometer made by the India Rubber, Gutta Percha and Telegraph Works Co at Telegraph Works Silvertown, London.
The Galvanometer was a very sensitive type of sensitive ammeter used for detecting electric current. It is an analogue electromechanical actuator that produces a rotary deflection of the pointer in response to electric current through its coil in a magnetic field.

Galvanometers were the first instruments used to detect and measure electric currents and were used to detect signals from long submarine cables,