Developments on magnetic and acoustic mines at the Admiralty Mining Establishment

The paper gives an outline of the basic principles and the development of British magnetic and acoustic mines. It opens with a brief history of mining prior to 1939 and thereafter describes the method of detecting ships and countering the effects of explosions and sweeps. It traces the development of mine circuits from the simple single-contact circuit to the combined dual detection circuits and gives details of the mines and components. The use of the magnetic mehtod of detection as a trigger device for heavy battery-consumption electronic circuits is given, and the paper closes with a brief comparison of British and German mining.