Throughout most of history, the passage of time was registered by familiar regularities such as day and night and the phases of the moon, or more accurately by the apparent motions of certain stars. The second was defined by the ancient Babylonians to be 1/84,600 of a day. Modern calendars are still based on astronomical time using the Gregorian calendar, introduced in 1582, in which the year is defined as 365.2425 days.
Until the scientific revolution and the ages of exploration and industrialization that followed, most people had no need for accurate clocks. Farmers and fishermen measured time in relation to familiar processes in the cycle of work and domestic chores. Labor took place in the natural period from dawn to dusk. The sundial was widely used to tell time during the day. The great advance in the accuracy of household clocks came about in the mid-seventeenth century with the application of the pendulum, which had been introduced into scientific experiments by Galileo in 1602. English clock- and watchmaking became dominant in 1680 and remained so until competition from the French and Swiss caught up about a century later.
In 1759 John Harrison produced a clock that could keep exact Greenwich Mean Time (the mean solar time of the meridian of the Royal Observatory in Greenwich, England, used as the prime basis of standard time) at sea, enabling mariners to determine their longitude on the globe and making accurate marine navigation possible for the first time. Today the primary time standard is provided by a Cesium Fountain atomic clock at the National Institute for Standards and Technology laboratory in Boulder, Colorado, which will not gain or lose a second in more than 60 million years.
With the rise of science, the second has undergone several redefinitions to make it more useful in the laboratory. The most recent change occurred in 1967, when the second was redefined by international agreement as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine energy levels of the ground state of the Cesium133 atom at rest at absolute zero. The minute remains 60 seconds, the hour remains 60 minutes, and the day remains 24 hours, following ancient traditions. The day is still taken to be 84,600 seconds, as in ancient Babylonia. Modern calendars need to be corrected occasionally to keep them in harmony with the seasons because of the lack of complete synchronization between atomic time and the motions of astronomical bodies.
Nothing seems so ubiquitous—so absolute and universal—as time. Yet, in his 1905 “special theory of relativity” Albert Einstein showed that the times measured on clocks are different for clocks that are moving with respect to one another—an effect called “time dilation.” This called into question some of the deepest intuitions of time. No moment in time can be labeled a universal “present.” There is no past or future that applies to every point in space. Two events separated in space can never be judged to be objectively simultaneous. The whole notion of cause and effect has to be carefully rethought.
Unless one is making highly precise measurements with atomic clocks, time dilation is important only when the relative speeds of clocks are near the speed of light, so there are not noticeable effects in everyday life. However, Einstein’s theory has been confirmed by a century of experiments involving high-energy particles that move near the speed of light, as well as low-speed measurements with atomic clocks. Although it is not necessary to take into account the relativity of time in the social sphere, it is important not to draw universal, philosophical, or metaphysical conclusions based on notions related to time that are inferred from normal human experience.
Philosophers and theologians have introduced alternate “metaphysical times” more along the lines of common experience, but these have no connection with scientific observations. Scientific models uniformly assume that time is, by definition, what is measured on a clock and that time is relative.
SEE ALSO Capitalism; Industrialization; Industry; Modernization; Productivity; Revolutions, Scientific; Science; Thompson, Edward P.; Work; Work Day
Davies, Paul. 1995. About Time: Einstein’s Unfinished Revolution. New York: Simon and Schuster.
Sobel, Dava. 1995. Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time. New York: Walker.
Stenger, Victor J. 2000. Timeless Reality: Symmetry, Simplicity, and Multiple Universes. Amherst, NY: Prometheus Books.
Stenger, Victor J. 2006. The Comprehensible Cosmos: Where Do the Laws of Physics Come From? Amherst, NY: Prometheus Books.
Thompson, E. P. 1967. Time, Work-Discipline, and Industrial Capitalism. Past and Present 38 (December): 56-97.
Victor J. Stenger
Clock and Watch Industry
CLOCK AND WATCH INDUSTRY
CLOCK AND WATCH INDUSTRY. The history of American clock-and watchmaking is a microcosm of the early history of American manufacturing. It includes the story of a tremendously talented line of artisans and of the training that passed from one to the other. Their ingenuity led to the spread of the "American system" of production—a forerunner of mass production. Finally, large-scale production of clocks and watches depended on the development of an elaborate system of distribution, through which the clocks and watches produced in such large quantities were distributed to urban and rural Americans.
The first clockmaker of record in America was Thomas Nash, an early settler of New Haven in 1638. Throughout the seventeenth century, eight-day striking clocks with brass movements, similar to those made in England, were produced by craft methods in several towns and villages in Connecticut. The wooden clock was not made in America until the eighteenth century, although it was known to exist in Europe in the seventeenth century, probably originating in Germany or Holland. By 1745 Benjamin Cheney of East Hartford was producing wooden clocks, and there is some evidence that these clocks were being made as early as 1715 near New Haven. Cheney was not the only maker of wooden clocks during the second half of the eighteenth century, but he was the most successful. Benjamin Willard, founder of the Willard Clock dynasty of Massachusetts, was apprenticed to Cheney.
The main line of descent of the American clock industry derives from Thomas Hatland, who emigrated from England in 1773 and opened a shop in Norwich, Connecticut. A clock-and watchmaker employing traditional craft methods, he was the first prominent European in that trade to settle in Connecticut. Hatland trained a substantial number of talented clockmakers, the most famous of whom was Daniel Burnap, who established his own business in East Windsor about 1780. Together Hat-land and Burnap were the forerunners of the modern, industrial era of clockmaking. This distinction derives from the fact that Eli Terry, the first to systematize clock production on a basis similar to that of interchangeable parts manufacture, was apprenticed to Daniel Burnap in 1786. It was most probably under Burnap's tutelage that Terry, who is recognized as the outstanding Connecticut clockmaker of the nineteenth century as well as the originator of clockmaking by machinery, was introduced to the concept of volume production as opposed to the customary practice of production to order.
Leaving Burnap's shop, Terry commenced business at Plymouth, Connecticut, in 1794. Shortly after 1800 he began to produce wooden clocks in quantity and in 1808 contracted with the Porter brothers of Waterbury for the production of 4,000 wooden clock movements at $4 each. Production in such quantities was unheard of up to that time, and the contract price contrasted sharply with the more usual $25 average price for movements. About 1814 Terry designed and manufactured the thirty-hour wooden shelf clock, hundreds of thousands of which were produced until his retirement in 1833.
Seth Thomas and Chauncey Jerome, both of whom worked for Eli Terry, greatly elaborated the system of factory production and carried the clock industry into its distinctly modern phase. Jerome worked for Terry for a year or two after 1816. Then he engaged in itinerant clockmaking and moved to Bristol in 1821. In 1825 Jerome designed the bronze looking-glass clock, which was an instant commercial success. Even though Joseph Ives of Bristol must be given credit for the pioneer development of the cheap American brass clock, which evolved from his work around 1815, it was Chauncey Jerome who, in 1838, developed the commercial possibilities of the thirty-hour rolled-brass movement. By 1842 Jerome was exporting brass clocks in large quantities to England. By 1855 almost all common clocks in America were brass, the four largest firms producing 400,000 rolled-brass movements in that year. Virtually every major firm in existence at the end of the nineteenth century could trace its descent from these early Connecticut-based establishments.
Watchmaking helped establish and carry forward a new standard of accuracy in American metalworking. Until World War I, nearly all watches produced in the United States were pocket watches, and for much of this time they were luxury goods. Although watches were probably made in America before the Revolution, the earliest production of watches in some volume is accorded to Thomas Haftand of Norwich, Connecticut. Between 1809 and 1817 Luther Goddard of Shrewsbury, Massachusetts, produced about 500 movements. Goddard learned the art of clockmaking from his cousin Simon Willard, son of Benjamin Willard; and thus this line of mechanical influence can be traced from Benjamin Cheney. Between 1836 and 1841 James and Henry Pitkin of East Hartford, Connecticut, made perhaps 800 movements, using the most elaborate tools known in America up to that time. Shortly before 1850 Aaron Dennison and Edward Howard made plans to manufacture watches on a volume basis, using a system of interchangeable parts, some of the parts being held to an accuracy of 1/10,000 of an inch. Dennison had learned clockmaking in Maine and watchmaking in Boston. Howard had been apprenticed to Aaron Willard Jr. for five years commencing in 1829—again in the Cheney line of descent. Other men who contributed prominently to the watchmaking industry throughout the balance of the nineteenth century were Ambrose Webster, Charles Mosley, Edward Marsh, and Charles Vander Woerd.
Dennison and Howard's attempts to use interchangeable parts in watch manufacture resulted in the formation of Dennison, Howard, and Davis, the firm that was the predecessor of the American Watch Company, later the Waltham Watch Company. When it was formed in 1850, the Waltham Watch Company was the only firm manufacturing watches in the United States, and it maintained a virtual monopoly on watch production through the 1870s. Although the factory used machinery, it depended on workers' abilities to manipulate and adapt very complicated technology. Owners offered generous wages and benefits, a clean working environment, and promises of promotion to retain and recruit the highly skilled labor force they needed. New watchmaking firms were established in the years just preceding and following the Civil War, and Waltham employees were in high demand by companies in Chicago, Providence, Springfield, Massachussetts, and Springfield, Illinois. All American watchmaking firms can trace their lineage either through the Waltham Watch Company prior to 1885 or through personnel associated with that firm. The watchmaking business expanded in the 1890s, when many firms began marketing cheaper "dollar watches." Just as Eli Terry had made clocks into an affordable item for many Americans, now watches were something that many people could see themselves owning. These watches did not use the jeweled parts that had been part of older and more expensive watches. Rather, a punch press was used to stamp highly standardized and cheaper parts out of sheets of metal. Simultaneously, railroads issued new requirements for the watches worn by their employees. Because reliable time-keeping was so essential to the scheduling and operation of railroads, the watches worn by employees had to be of very high quality; these watches represented the opposite end of the spectrum of "dollar watches." Firms developed ever more sophisticated techniques to produce ever more precise watches. Watches gained an even bigger market when American firms began producing wristwatches. First developed in Switzerland and marketed as women's watches, wristwatches were distributed to soldiers in World War I, and they quickly became popular items for both men and women.
The American watch industry declined considerably in the interwar years, the result of over expansion and the high costs of specialized machinery. Only seven firms survived the 1930s, and the industry continued to contract in subsequent decades. While many Americans continue to wear watches, these are often manufactured overseas.
Gitelman, H. M. "The Labor Force at Waltham Watch during the Civil War Era." Journal of Economic History 25 (June 1965).
Hounshell, David A. From the American System to Mass Production, 1800–1932. Baltimore: Johns Hopkins University Press, 1984.
Jaffee, David. "Peddlers of Progress and the Transformation of the Rural North, 1760–1860." Journal of American History 78 (September 1991).
Murphy, John Joseph. "Entrepreneurship in the Establishment of the American Clock Company." Journal of Economic History 26 (June 1966).
clock, 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
The operation of a clock depends on a stable mechanical oscillator, such as a swinging pendulum or a mass connected to a spring, by means of which the energy stored in a raised weight or coiled spring advances a pointer or other indicating device at a controlled rate. It is not definitely known when the first mechanical clocks were invented. Some authorities attribute the first weight-driven clock to Pacificus, archdeacon of Verona in the 9th cent. Gerbert, a learned monk who became Pope Sylvester II, is often credited with the invention of a mechanical clock, c.996.
Mechanical figures that struck a bell on the hour were installed in St. Paul's Cathedral, London, in 1286; a dial was added to the clock in the 14th cent. Clocks were placed in a clock tower at Westminster Hall, London, in 1288 and in the cathedral at Canterbury in 1292. In France, Rouen was especially noted for the skill of its clockmakers and watchmakers. Probably the early clock closest to the modern ones was that constructed in the 14th cent. for the tower of the palace (later the Palais de Justice) of Charles V of France by the clockmaker Henry de Vick (Vic, Wieck, Wyck) of Württemburg. Until the 17th cent. few mechanical clocks were found outside cathedral towers, monasteries, abbeys, and public squares.
The early clocks driven by hanging weights were bulky and heavy. When the coiled spring came into use (c.1500), it made possible the construction of the smaller and lighter-weight types. By applying Galileo's law of the pendulum, the Dutch scientist Christiaan Huygens invented (1656 or 1657) a pendulum clock, probably the first. Early clocks used in dwellings in the 17th cent. were variously known as lantern clocks, birdcage clocks, and sheep's-head clocks; they were of brass, sometimes ornate, with a gong bell at the top supported by a frame. Before the pendulum was introduced, they were spring-driven or weight-driven; those driven by weights had to be placed on a wall bracket to allow space for the falling weights. These clocks, probably obtained chiefly from England and Holland, were used in the Virginia and New England colonies.
Clocks with long cases to conceal the long pendulums and weights came into use after the mid-17th cent.; these were the forerunners of the grandfather clocks. With the development of the craft of cabinetmaking, more attention was concentrated on the clock case. In France the tall cabinet clocks, or grandfather clocks, were often of oak elaborately ornamented with brass and gilt. Those made in England were at first of oak and later of walnut and mahogany; simpler in style, their chief decoration was inlay work.
Electric and Other Clocks
Electric clocks were made in the second half of the 19th cent. but were not used extensively in homes until after c.1930. In an analog clock the hands of an electric clock are driven by a synchronous electric motor supplied with alternating current of a stable frequency. Digital clocks use LCDs (liquid crystal displays) or LEDs (light emitting diodes) to form the numbers indicating the time. The quartz clock, invented c.1929, uses the vibrations of a quartz crystal to drive a synchronous motor at a very precise rate. Some quartz clocks have an error of less than one thousandth of a second per day. The atomic clock, which is based upon the frequency of an atomic or molecular process, is even more precise; a state of the art atomic clock, such as NIST-F2 (which is one of two U.S. time frequency standard clocks), is accurate to one second in 300 million years.
Some Famous Clocks
One of the most famous clocks is in the cathedral of Strasbourg; the clock was first placed in the cathedral in 1352, and in the 16th cent. it was reconstructed. In the 19th cent. a new astronomical clock (so called because it shows the current positions of the sun, moon, and other heavenly bodies in addition to the time of day) similar to the original clock was constructed; its elaborate mechanical devices include the Twelve Apostles, a crowing cock, a revolving celestial globe, and an automatic calendar dial. Among other well-known clocks of the world are the clock known as Big Ben in the tower next to Westminster Bridge in the British Houses of Parliament and the tower clock in the Metropolitan Life Insurance Company building, New York City.
See F. J. Britten, Old Clocks and Watches and Their Makers (1976); D. S. Landes, Revolution in Time: Clocks and the Making of the Modern World (1985); J. E. Barnett, Time's Pendulum: The Quest to Capture Time from Sundials to Atomic Clocks (1998); E. Bruton, Collector's Dictionary of Clocks and Watches (1999); J. Jesperson and J. Fitz-Randolph, From Sundials to Atomic Clocks: Understanding Time and Frequency (2d ed. 1999).
clock1 / kläk/ • n. a mechanical or electrical device for measuring time, indicating hours, minutes, and sometimes seconds, typically by hands on a round dial or by displayed figures. ∎ (the clock) time taken as a factor in an activity, esp. in competitive sports: her life is ruled by the clock. ∎ inf. a measuring device resembling a clock for recording things other than time, such as a speedometer, taximeter, or odometer. ∎ see time clock. • v. [tr.] inf. 1. attain or register (a specified time, distance, or speed): Thomas has clocked up forty years service | [intr.] the book clocks in at 989 pages. ∎ achieve (a victory): he clocked up his first win of the year. ∎ record as attaining a specified time or rate: the tower operators clocked a gust of 185 mph. 2. inf. hit (someone), esp. on the head. PHRASES: around (or round) the clock all day and all night. run out the clock Sports deliberately use as much time as possible in order to preserve one's own team's advantage. stop the clock allow extra time by temporarily ceasing to count the time left before a deadline arrives. watch the clock (of an employee) be overly strict or zealous about not working more than one's required hours.PHRASAL VERBS: clock in (or out) (of an employee) punch in (or out). clock2 • n. dated an ornamental pattern woven or embroidered on the side of a stocking or sock near the ankle.
The clock rate is the frequency, expressed in hertz, at which active transitions of a given clock signal occur. The active transition may be from a low to a high voltage level, or vice versa, but will always be followed after a fixed time by an opposite inactive transition. The clock signal is thus formed as a series of fixed-width pulses having a fixed repetition frequency (see diagram). The pulse width, t1, is often 50% of the pulse repetition period, t2, i.e. t1 = t3. The clock rate is 1/t2 hertz. A clock cycle is considered to be one complete cycle of the clock signal and will always contain one active transition of the clock. For the clock signal illustrated, a clock cycle occurs in t2 seconds.
Because of its constant rate, a clock signal is used to initiate actions within a sequential logic circuit and to synchronize the activities of a number of such circuits. These circuits are said to be clocked. The primary clock rate controls the fastest parts of a computer while slower components are timed by numerous submultiples of the basic frequency.