Earth battery

An Earth battery is a pair of electrodes made of two dissimilar metals, such as iron and copper, which are buried in the soil or immersed in the sea. Earth batteries act as water activated batteries and if the plates are sufficiently far apart, they can tap telluric currents. Earth batteries are sometimes referred to as telluric power sources and telluric generators.

One of the earliest examples of an earth battery was built by Alexander Bain in 1841 in order to drive a —a device that transforms the flow or changes in pressure of a fluid into mechanical energy. Bain buried plates of zinc and copper in the ground about one meter apart and used the resulting voltage, of about one volt, to operate a clock. Carl Friedrich Gauss, who had researched Earth's magnetic field, and Carl August von Steinheil, who built one of the first electric clocks and developed the idea of an "Earth return" (or "ground return"), had previously investigated such devices.

Daniel Drawbaugh received U.S. Patent 211,322 for an Earth battery for electric clocks (with several improvements in the art of Earth batteries). Another early patent was obtained by Emil Jahr U.S. Patent 690,151 Method of utilizing electrical Earth currents). In 1875, James C. Bryan received U.S. Patent 160,152 for his Earth Battery. In 1885, George Dieckmann, received US patent U.S. Patent 329,724 for his Electric Earth battery. In 1898, Nathan Stubblefield received U.S. Patent 600,457 for his electrolytic coil battery, which was a combination of an earth battery and a solenoid. (For more information see US patents 155209, 182802, 495582, 728381, 3278335, 3288648, 4153757 and 4457988.) The Earth battery, in general, generated power for early telegraph transmissions and formed part of a tuned circuit that amplified the signalling voltage over long distances.

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