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Clocks and Watches, devices used to measure or indicate the passage of time. A clock, which is larger than a watch, is usually intended to be kept in one place; a watch is designed to be carried or worn. Both types of timepieces require a source of power and a means of transmitting and controlling it, as well as indicators to register the lapse of time units. In a clock, the source of power may be produced by weight, a mainspring, or an electric current . Except in electric or electronic clocks, periodic adjustments, such as lifting the weight or tightening the spring, are needed. The motive force generated by the power source in a mechanical clock is transmitted by a gear train and regulated by a pendulum or a balance wheel. In such a clock, the time may be reported audibly by the striking of a gong or chime and is registered visually by the rotation of wheels bearing numerals or by the position of hands on a dial. In electric or electronic clocks, time may be shown by a display of numbers. A mechanical watch uses a coiled spring as its power source. As in spring-powered clocks, the watch conserves energy by means of a gear train, with a balance wheel regulating the motive force. In self-winding watches, the mainspring is tightened automatically by means of a weight on a rotor that responds to the arm movements of the wearer. In the electric clocks used in homes today, a small motor runs in unison with the power-station generator, which is regulated to deliver an alternating current of precisely 60 cycles per second. Electric currents may also be used to keep the movements of several “slave” clocks synchronized with the pendulum in a master clock. The quartz-crystal clock developed in 1929 for precision timekeeping employs a ring of quartz that is connected to an electrical circuit and made to oscillate between 10,000 and 100,000 hertz (cycles per second). The high-frequency oscillation is converted to an alternating current, reduced to a frequency more convenient for time measurement, and thus made to drive the motor of a synchronous clock or a digital display. The maximum error of the most accurate quartz-crystal clocks is plus or minus one second in ten years. The electric or electronic watch is powered by a small battery that functions for about one year without replacement. The battery may drive the balance wheel of an otherwise mechanical clock, or it may be used to drive the oscillations of either a small tuning fork or a quartz crystal. Carefully constructed mechanical timepieces known as chronometers are precision devices used by navigators in the determination of their longitude at sea and by astronomers and jewelers for calibrating measuring devices. The first successful chronometer was constructed in 1761 by English horologist John Harrison. These portable instruments are mounted on a box on gimbals so as to maintain the delicate movements in a level position. The modern wrist chronometer is a precision watch regulated in different positions and at various temperatures and certified by testing bureaus in Switzerland. Another precision timekeeper is the chronograph, which not only provides accurate time but also registers elapsed time in fractions of a second. Various forms of chronographs exist, including the telemeter, which measures the distance of an object from the observer; the tachometer, which measures speed of rotation; the pulsometer, which determines pulse rate; and the production counter, which indicates the number of products made in a given time. The timer, or stopwatch, a form of chronograph used in athletic contests, shows elapsed time without providing the time of day. The most precise timekeeping devices are atomic clocks. Their uses include measuring the rotation of the earth, which may vary by 4 to 5 milliseconds per day, and aiding navigational systems such as the global positioning system in computing distances. Atomic clocks are tuned to the frequency of the electromagnetic waves that are emitted or absorbed when certain atoms or molecules make the transition between two closely spaced, or hyperfine, energy states. Because the frequency of these waves is unaffected by external forces, the corresponding period of the waves can be used as a standard to define time intervals. The cesium-atom clock is used to define the second, the basic unit of time of the International System of Units. In this clock, cesium-133 atoms in one hyperfine energy state are subjected to microwave radiation that is near the resonant frequency of the transition to another hyperfine energy state. The microwave frequency is adjusted, and when the correct frequency is reached, many atoms make the transition to the new energy state. The frequency of the microwave radiation is then used to determine the period of the microwave, or the time interval between wave crests. The second is defined as the duration of 9,192,631,770 periods of radiation. The hydrogen clock and the ammonia clock rely on the maser principle. In a hydrogen clock, a focused magnetic field selects hydrogen atoms in a specific hyperfine energy state. These atoms are forced to change to a lower energy state. When many atoms make the transition, they begin to oscillate between the two states, emitting energy in the form of an electromagnetic wave. The period of this emitted wave is used to measure time. The hydrogen clock is very stable for several hours at a time. Throughout history, time has been measured by the movement of the earth relative to the sun and stars. The earliest type of timekeeper, dating from as far back as 3500 bc, was the shadow clock, or gnomon, a vertical stick or obelisk that casts a shadow. An Egyptian shadow clock of the 8th century bc is still in existence. The first hemispherical sundial was described about the 3rd century bc by Chaldean astronomer Berossus. In 1650, before the introduction of the pendulum clock, a clock could be found in a Boston, Massachusetts, church tower. The first public clock in New York City was built in 1716 for the City Hall at Nassau and Wall streets, and a clock was installed in Independence Hall in Philadelphia, Pennsylvania, by 1753. Mass production of clocks with interchangeable parts began in the United States after the American Revolution (1775-1783). Because of the scarcity of metals, well-seasoned wood was used for the movements. In the early 1800s, Simon Willard of Roxbury, Massachusetts, patented the popular banjo clock, and Eli Terry of Connecticut evolved a shelf clock called the pillar-and-scroll clock, which required winding only once a day. About the same time in Plymouth Hollow (now Thomaston), Connecticut, Seth Thomas founded the Seth Thomas Clock Company, which was, in the mid-20th century, one of the largest clock factories in the world. Watches were not produced in significant volume in the United States until about 1800, when Thomas Harland of Norwich, Connecticut, established a factory with a capacity of 200 units a year. In 1836 the Pitkin brothers of East Hartford, Connecticut, produced the first American-designed watch and the first containing a machine-made part. Despite a reputation for accuracy and durability, the manufacture of this watch was discontinued as a result of the depression of 1837, which temporarily crippled American industry. Restoration is an important part of the business. Care and thought is essential in sympathetic restoration. High quality work is time consuming and it is therefore necessary to make an appointment to visit the shop for either sales or restoration. Early 19th Century Lancaster Pinion Cutter Typical of the traditional type of tools used during our sympathetic restoration process. Clocks are more than just a livelihood to us. Special,attractive and genuine pieces require experience and a discerning eye to collect and I hope the pictures convey the merit of pieces displayed. To be sure of receiving the best of our time and attention please call and make an appointment. For over 20 years, I have been working as a specialist restorer. My experience with antique clocks began with a five year apprenticeship and has continued with work on pieces by respected makers, thus gaining vaulable familiarity with various styles and mechanisms for work than can include major rebuilding or delicate but sympathetic restoration A selection of carefully chosen stock is always available to view by appointment. Barometers as well as timepieces which range from late 17th Century through to early 19th Century longcase, bracket and lantern clocks are usually offered. Although English clocks form the major part of the selection, French decorative pieces with high quality cases and movements are also bought and sold as are the occasional sun dial or interesting scientific instrument.
antique clocks grandfather clocks lantern clocks antique clock restoration sundials antique barometers french decorative clocks interior design clocks longcase clocks
lantern clocks