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watch,small, portable timepiece usually designed to be worn on the person. Other kinds of timepieces are generally referred to as clocksclock,
instrument for measuring and indicating time. Predecessors of the clock were the sundial, the hourglass, and the clepsydra. See also watch. The Evolution of Mechanical Clocks
..... Click the link for more information. . At one time it was generally believed that the first watches were made in Nuremburg, Germany, c.1500. However, there is now evidence that watches may have appeared at an earlier date in Italy. Early watches were ornate, very heavy, and made in a variety of shapes, e.g., pears, skulls, and crosses; the faces were protected by metal latticework. Watch parts were made by hand until c.1850, when machine methods were introduced by watch manufacturers in the United States. The introduction of machine-made parts not only cut manufacturing costs but increased precision and facilitated repairs. To insure the accuracy of a watch over a long period, bearings made of jewels (usually synthetic sapphires or rubies) are utilized at points subject to heavy wear. The mechanical watch contains a mainspring to drive the watch's mechanism. Part of the mechanism includes a hairspring and an oscillating balance wheel to control the rate at which the mechanism moves. The mainspring is wound by the wearer when he turns a knob outside the watch's casing. The automatic, or self-winding, watch has a mainspring that is wound by an oscillating weight, contained in the watch, that is set into motion by the movements of the wearer. The stopwatch can be stopped or started at will by pressing a tiny button on its edge and is used for timing such events as races. The electric watch, which was introduced by the Hamilton Watch Company in 1957, also uses a hairspring and a balance wheel to regulate the rate at which its mechanism moves, but it has no mainspring. In recent years sophisticated electronic watches have been developed. One type uses the vibrations of an electrically driven tuning fork to determine the rate at which a small motor drives the hands. In another type a crystal oscillator provides a signal that regulates this motion. In the most common type a quartz crystal oscillator is joined to digital counting and digital display circuits, thus eliminating all moving parts. See liquid crystalliquid crystal,
liquid whose component particles, atoms or molecules, tend to arrange themselves with a degree of order far exceeding that found in ordinary liquids and approaching that of solid crystals.
..... Click the link for more information. . Quartz watches with digital displays now account for nearly half of all watch production, since they are inexpensive to produce but are accurate to within several seconds per month. Electric and electronic watches are powered by tiny long-lasting batteries. See chronometerchronometer
, instrument for keeping highly accurate time, used especially in navigation. Before the advent of radio time signals it was the only device that provided the time accurately enough for a ship at sea to determine its longitude.
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See C. Clutton and G. Daniels, Watches: A Complete History (3d ed. 1979); J. Zagoory and H. Chan, A Time to Watch: The Wrist Watch as Art (1985); E. Bruton, History of Clocks and Watches (1989).
Basic type of duty on ships and vessels, for the purpose of maintaining their combat readiness (in the navy) and navigational safety. The watch on naval ships is divided into general ship’s watch (combat watch, bridge watch at sea, and anchor watch) and special (for example, engine-crew watch). The distribution of personnel in shifts is provided for in special rosters. The term “watch” is also used to designate the interval of time during which one shift of a 24-hour detail stands watch; its duration is not more than six hours. The most difficult watch is considered to be the first night watch from 0:01 to 4:00 hours, which is called the dogwatch in all the navies of the world.
(2) Obsolete term used to designate half of the crew of a ship (vessel). Up until the 19th century a ship’s crew was divided into two watches; the first watch was located (hung its hammocks) in the right-hand portion of the ship’s hull and the second watch, in the left portion.