Nikola Tesla Patents
236 the circuit is either the same as that of the source or a harmonic thereof. The receiving circuit proper, diagrammatically shown in fig. 3, comprises a terminal E', conductor C¹, a sensi! tive device A' and a conductor A" leading to the ground, conveniently through a connection to the metal keel B¹ of the vessel. The terminal E' should present a large conducting surface and should be supported as high as practicable on a standard D', which is shown as broken in fig. 2, but such provisions are not always necessary. It is important to insulate very well the donductor C', in whatever manner it be supported: The circuit or path just referred to forms also a part of a local circuit, including a relay magnet a and a battery a', the electro-motive force of which is, as before explained, so determined that the di electric layers in the sensitive device A¹ are subjected to a great strain, normally no appreciable current flowing through the local circuit. But when an electrical disturbance reaches the circuit, the dielectric films are broken down, the resistance of the device A¹ is suddenly and greatly diminished and a current traverses the relay magnet a.. The particular sensitive device employed is shown in general views and in detail in figs. 4, 6, 7 and 8. It consists of a metal cylinder c with insulating heads c', through which passes a central metallic rod c". A small quantity of grains d of conducting material, such as an oxydized metal is placed in the cylinder. (12)
