Cox's timepiece is a clock developed, in the 1760s, by James Cox (with the help of John Joseph Merlin). Cox was quite open about his machine's operation (unlike many other perpetual motion inventors). The device is powered from changes in atmospheric pressure via a mercury barometer. The clock still exists today but was deactivated at the time of the clock's relocation.^[1] A wall clock A (from the Latin cloca, bell) is an instrument for measuring time, usually for measuring time of intervals less than a day--as opposed to a calendar. ... Events and Trends King George III ascends the British throne in 1760. ... James Cox can refere to one of several different individuals in history. ... This article or section should include material from Parallel Path See also Perpetuum mobile as a musical term Perpetual motion machines (the Latin term perpetuum mobile is not uncommon) are a class of hypothetical machines which would produce useful energy in a way science cannot explain (yet). ... An inventor is a person who creates new inventions, typically technical devices such as mechanical, electrical or software devices or methods. ... diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure above any area in the Earths atmosphere caused by the weight of air. ... General Name, Symbol, Number mercury, Hg, 80 Chemical series transition metals Group, Period, Block 12, 6, d Appearance silvery white Atomic mass 200. ... Schematic drawing of a simple mercury barometer with vertical mercury column and reservoir at base Table of Pneumaticks, 1728 Cyclopaedia A barometer is an instrument used to measure atmospheric pressure. ...

The clock is similar to other mechanical clocks, except it does not need winding. The change of pressure in the Earth's atmosphere causes sufficient movement of the winding mechanism. This keeps the mainspring coiled inside the barrel. The clock is designed to enable the timepiece to run indefinitely and overwinding is prevented by a safety mechanism. The prime mover, encased in a finely detailed clock body, is a Fortin mercury barometer. The barometer contained 68 kilograms (150 pounds) of mercury. The Cox timepiece resides in the Victoria and Albert Museum of Great Britain.^[2] Layers of Atmosphere (NOAA) Air redirects here. ... Mainspring (U.S.A. motor spring): In a watch, long strip of hardened and blued steel or of a specially alloyed steel, between 2oo & 3oo millimeters in length and 0. ... For the philosophical/theological concept of a prime mover (that is, a self-existent being that is the ultimate cause or mover of all things), see cosmological argument. ... The international prototype, made of platinum-iridium, which is kept at the BIPM under conditions specified by the 1st CGPM in 1889. ... The pound is the name of a number of units of mass, all in the range of 300 to 600 grams. ... The Cromwell Road entrance to the Victoria and Albert Museum The Victoria and Albert Museum viewed from Thurloe Square The main interior courtyard of the Victoria and Albert Museum in 2004. ...

Related to this is Cornelis Drebbel's device of 1610 (though it is unknown if Cox knew of it). It was a machine that told the time, date, and season. The gold machine was mounted in a globe on pillars and was powered by changes in air pressure (a sealed glass tub with liquid varied in volume through atmospheric pressure changes, rewinding constantly). Cornelius Jacobszoon Drebbel (Alkmaar, 1572 - London, November 7, 1633) was a Dutch inventor. ...

See also

• History of perpetual motion machines

The history of perpetual motion machines (also known as the history of free energy and history of over unity machines) dates as far back as the 8th century, and probably further. ...

References

1. ^ Ord-Hume, Arthur W. J. G. (1977). Perpetual Motion: The History of an Obsession. New York: St. Martin's Press. ISBN 031260131X.
2. ^ Bruton, Eric (1979). The History of Clocks and Watches. New York: Rizzoli International Publications. ISBN 0847802612.

External articles

• Lienhard, John H., "No. 527: Cox's Perpetual-Motion Machine". The Engines of Our Ingenuity, 1997.