History of timekeeping devices

1423: 2248: 882: 582: 354: 2045: 7958: 1178: 1649: 370: 1018: 1740:, were leaders in case design and ornamental clocks. Le Roy belonged to the fifth generation of a family of clockmakers, and was described by his contemporaries as "the most skillful clockmaker in France, possibly in Europe". He invented a special repeating mechanism which improved the precision of clocks and watches, a face that could be opened to view the inside clockwork, and made or supervised over 3,500 watches during his career of almost five decades, which ended with his death in 1759. The competition and scientific rivalry resulting from his discoveries further encouraged researchers to seek new methods of measuring time more accurately. 2056: 253: 891: 1551: 1367: 1237: 1560: 2228: 1569: 2239: 2386: 1879:, and the use of two different metals to reduce the problem of expansion caused by temperature variation. He travelled to London to seek assistance from the Board of Longitude in making a sea clock. He was sent to visit Graham, who assisted Harrison by arranging to finance his work to build a clock. After 30 years, his device, now named "H1" was built and in 1736 it was tested at sea. Harrison then went on to design and make two other sea clocks, "H2" (completed in around 1739) and "H3", both of which were ready by 1755. 1744: 827: 30: 7952: 1267:. A verge, or vertical shaft, is forced to rotate by a weight-driven crown wheel, but is stopped from rotating freely by a foliot. The foliot, which cannot vibrate freely, swings back and forth, which allows a wheel to rotate one tooth at a time. Although the verge and foliot was an advancement on previous timekeepers, it was impossible to avoid fluctuations in the beat caused by changes in the applied forces—the earliest mechanical clocks were regularly reset using a sundial. 694: 1860: 1895: 2219: 868:(66 ft) has been estimated. The gradual introduction of metal disks, most likely beginning during the Song dynasty, allowed craftsmen to more easily create seals of different sizes, design and decorate them more aesthetically, and vary the paths of the grooves, to allow for the changing length of the days in the year. As smaller seals became available, incense seal clocks grew in popularity and were often given as gifts. 2025:, limited their practical use elsewhere. In 1932, a quartz clock able to measure small weekly variations in the rotation rate of the Earth was developed. Their inherent physical and chemical stability and accuracy has resulted in the subsequent proliferation, and since the 1940s they have formed the basis for precision measurements of time and frequency worldwide. 783:

with a system of four weights, counterweights, and strings regulated by a system of floats in a water container with siphons that regulate the automatic continuation of the clock. The principles of this type of clock are described by the mathematician and physicist Hero, who says that some of them work with a chain that turns a gear in the mechanism.

2119:, from around half an hour to within a few minutes per day. Some dispute remains as to whether the balance spring was first invented by Huygens or by Hooke; both scientists claimed to have come up with the idea of the balance spring first. Huygens' design for the balance spring is the type used in virtually all watches up to the present day. 2691:

Giovanni de Dondi's work has been replicated based on the designs. His clock was a seven-faced construction with 107 moving parts, showing the positions of the Sun, Moon, and five planets, as well as religious feast days. His clock has inspired several modern replicas, including some in London's

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Harmonically-driven clocks depend on some form of deformation from an equilibrium position; the resulting oscillations have a maximum amplitude when they receive energy at a frequency close to their natural undamped frequency. The main examples of such harmonic oscillators used to keep time are: the

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of £20,000, equivalent to millions of pounds today, for anyone who could determine the longitude to within 50 kilometres (31 mi) at a latitude just north of the equator. The position of a ship at sea could be determined to within 100 kilometres (62 mi) if a navigator could refer to a clock

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to operate a knocker that continuously struck a bell. The weight-driven clock was probably a Western European invention, as a picture of a clock shows a weight pulling an axle around, its motion slowed by a system of holes that slowly released water. In 1271, the English astronomer Robertus Anglicus

1089:

From the 15th century onwards, hourglasses were used in a wide range of applications at sea, in churches, in industry, and in cooking; they were the first dependable, reusable, reasonably accurate, and easily constructed time-measurement devices. The hourglass took on symbolic meanings, such as

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And Isaiah said, This sign shalt thou have of the Lord, that the Lord will do the thing that he hath spoken: shall the shadow go forward ten degrees, or go back ten degrees? And Hezekiah answered, It is a light thing for the shadow to go down ten degrees: nay, but let the shadow return backward ten

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enabled the use of longer, heavier pendulums with slower beats that had less variation, as they more closely resembled simple harmonic motion, required less power, and caused less friction and wear. The first known anchor escapement clock was built by the English clockmaker William Clement in 1671

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in 1656. Early versions erred by less than one minute per day, and later ones only by 10 seconds, very accurate for their time. Dials that showed minutes and seconds became common after the increase in accuracy made possible by the pendulum clock. Brahe used clocks with minutes and seconds to

782:

during the 3rd century BC. Archimedes created his astronomical clock, which was also a cuckoo clock with birds singing and moving every hour. It is the first carillon clock as it plays music simultaneously with a person blinking his eyes, surprised by the singing birds. The Archimedes clock works

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that expands faster than glass. More accurate versions of this innovation contained the mercury in thinner iron jars to make them more responsive. This type of temperature compensating pendulum was improved still further when the mercury was contained within the rod itself, which allowed the two

1160:

Judaism, Christianity and Islam all had times set aside for prayer, although Christians alone were expected to attend prayers at specific hours of the day and night—what the historian Jo Ellen Barnett describes as "a rigid adherence to repetitive prayers said many times a day". The bell-striking

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Nec est hoc possibile, quod aliquod horologium sequatur omnino iudicium astronomie secundum veritatem. Conantur tamen artifices horologiorum facere circulum unum qui omnino moveatur secundum motum circuli equinoctialis, sed non possunt omnino complere opus eorum, quod, si possent facere, esset

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Incense seal clocks had a disk etched with one or more grooves, into which incense was placed. The length of the trail of incense, directly related to the size of the seal, was the primary factor in determining how long the clock would last; to burn 12 hours an incense path of around 20 metres

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in 1271 shows that medieval craftsmen were attempting to design a purely mechanical clock (i.e. only driven by gravity) during this period. Such clocks were a synthesis of earlier ideas derived from European and Islamic science, such as gearing systems, weight drives, and striking mechanisms.

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A problem with most clepsydrae was the variation in the flow of water due to the change in fluid pressure, which was addressed from 100 BC when the clock's water container was given a conical shape. They became more sophisticated when innovations such as gongs and moving mechanisms were

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observe stellar positions. The pendulum clock outperformed all other kinds of mechanical timekeepers to such an extent that these were usually refitted with a pendulum—a task that could be done without difficulty—so that few verge escapement devices have survived in their original form.

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meant that soldiers needed to protect the glass of their watches, and a guard in the form of a hinged cage was sometimes used. The guard was designed to allow the numerals to be read easily, but it obscured the hands—a problem that was solved after the introduction of shatter-resistant

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All timekeepers before the 13th century relied upon methods that used something that moved continuously. No early method of keeping time changed at a steady rate. Devices and methods for keeping time have improved continuously through a long series of new inventions and ideas.

1294:, written in the early part of the 14th century. It may be the first known literary description of a mechanical clock. There are references to house clocks from 1314 onwards; by 1325 the development of the mechanical clock can be assumed to have occurred. 1886:, has described H4 as "probably the most remarkable timekeeper ever made". After the completion of its sea trials during the winter of 1761–1762 it was found that it was three times more accurate than was needed for Harrison to be awarded the Longitude prize. 1639:

made major contributions to the development of pendulum clocks in the 17th and 18th centuries, having had an "unusually keen appreciation of the importance of precision". In measuring an accurate one-second pendulum, for example, the Italian astronomer Father

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Nor is it possible for any clock to follow the judgment of astronomy with complete accuracy. Yet clockmakers are trying to make a wheel which will make one complete revolution for every one of the equinoctial circle, but they cannot quite perfect their work.

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was one of the first clockmakers to recognise the potential of the balance spring and use it successfully in his pocket watches; the improved accuracy enabled watches to perform as well as they are generally used today, as a second hand to be added to the

1305:

1273 (reference to a payment for a mechanical clock dated to this year) is the earliest such large clock known. The clock has not survived. The first clock known to strike regularly on the hour, a clock with a verge and foliot mechanism, is recorded in

1081:

used 18 hourglasses on each ship during his circumnavigation of the globe in 1522. Though used in China, the hourglass's history there is unknown, but does not seem to have been used before the mid-16th century, as the hourglass implies the use of

774:, were unrivalled in their sophistication until the mid-14th century. Liquid-driven mechanisms (using heavy floats and a constant-head system) were developed that enabled water clocks to work at a slower rate. Some have argued that the first known 1534:. Harmonic oscillators can be used as accurate timekeepers as the period of oscillation does not depend on the amplitude of the motion—and so it always takes the same time to complete one oscillation. The period of a harmonic oscillator is completely 1434:

in the Middle Ages struck the time. Early clock dials showed hours; a clock with a minutes dial is mentioned in a 1475 manuscript. During the 16th century, timekeepers became more refined and sophisticated, so that by 1577 the Danish astronomer

1049:. His so-called "scribe" candle clock was invented to mark the passing of 14 hours of equal length: a precisely engineered mechanism caused a candle of specific dimensions to be slowly pushed upwards, which caused an indicator to move along a scale. 616: BC) Egyptian court official named Amenemhet, who is identified as its inventor. It is assumed that the object described on the inscription is a bowl with markings to indicate the time. The oldest surviving water clock was found in the tomb of 2169:(1899–1902), watches had been recognised as a valuable tool. Early models were essentially standard pocket watches fitted to a leather strap, but, by the early 20th century, manufacturers began producing purpose-built wristwatches. In 1904, 1349:

During the 14th century, striking clocks appeared with increasing frequency in public spaces, first in Italy, slightly later in France and England—between 1371 and 1380, public clocks were introduced in over 70 European cites.

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frame, held together with metal dowels and pegs. Two large stones supply the power, and cause ropes to unwind from wooden barrels. The barrels drive the main wheel (regulated by the escapement), and the striking mechanism and air

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persuaded nine fellow Jesuits "to count nearly 87,000 oscillations in a single day". They served a crucial role in spreading and testing the scientific ideas of the period, and collaborated with Huygens and his contemporaries.

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in 1656, was so much more accurate than other kinds of mechanical timekeepers that few verge and foliot mechanisms have survived. Other innovations in timekeeping during this period include inventions for striking clocks, the

1874:

had used his carpentry skills to construct a wooden eight-day clock. His clocks had innovations that included the use of wooden parts to remove the need for additional lubrication (and cleaning), rollers to reduce friction,

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Still, there were unexpected astronomical challenges; this clock gave the incorrect time for a century. This mistake was noticed only in 164 BC, when the Roman censor came to check and adjusted for the appropriate latitude.

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1360, which was said to have varied by up to two hours a day. For the next 300 years, all the improvements in timekeeping were essentially developments based on the principles of de Vick's clock. Between 1348 and 1364,

581: 1937:, first used electricity to sustain the motion of a pendulum clock, and so can be credited with the invention of the electric clock. On January 11, 1841, Bain and the chronometer maker John Barwise took out a 1505:, and discovered that this was only dependent on its length. Galileo never constructed a clock based on his discovery, but prior to his death he dictated instructions for building a pendulum clock to his son, 863:

used could be straight or spiralled; the spiralled ones were intended for long periods of use, and often hung from the roofs of homes and temples. Some clocks were designed to drop weights at even intervals.

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are the most accurate timekeeping devices in practical use today. Accurate to within a few seconds over many thousands of years, they are used to calibrate other clocks and timekeeping instruments. The U.S.

642:, and at the latest by the 1st millennium BC. Around 550 AD, Yin Kui (殷蘷) was the first in China to write of the overflow or constant-level tank in his book "Lou ke fa (漏刻法)". Around 610, two 1358:, built in 1392, is unique in that it still has its original medieval face. Above the clock are figures which hit the bells, and a set of jousting knights who revolve around a track every 15 minutes. 1387:

in guns— allowed small clocks to be built for the first time. The need for an escapement mechanism that steadily controlled the release of the stored energy, led to the development of two devices, the

1680:, which provided an accurate method for setting clocks. The equation of time was engraved on sundials so that clocks could be set using the Sun. In 1720, Joseph Williamson claimed to have invented a 1201:

made between 1226 and 1234 that shows a clock being slowed by water acting on a wheel. The illustration seems to show that weight-driven clocks were invented in western Europe. A treatise written by

1466:. The clock would be set to the local time of a starting point whose longitude was known, and the longitude of any other place could be determined by comparing its local time with the clock time. 1056:

was one of the few reliable methods of measuring time at sea, and it has been speculated that it was used on board ships as far back as the 11th century, when it would have complemented the

423:. It measured the passage of time by the shadow cast by its crossbar, and was oriented eastward in the mornings, and turned around at noon, so it could cast its shadow in the opposite direction. 2282:

Fob watches were starting to be replaced at the turn of the 20th century. The Swiss, who were neutral throughout World War I, produced wristwatches for both sides of the conflict. The

1949:, whom Bain met in London to discuss his ideas for an electric clock, produced his own version of the clock in November 1840, but Bain won a legal battle to establish himself as the inventor. 478:

with the invention of a hemispherical sundial hollowed out of stone; the path of the shadow was divided into 12 parts to mark the time. Greek sundials evolved to become highly sophisticated—

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The first pendulum clocks used a verge escapement, which required wide swings of about 100° and so had short, light pendulums. The swing was reduced to around 6° after the invention of the

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has speculated that incense clocks were invented in India. As incense burns evenly and without a flame, the clocks were safe for indoor use. To mark different hours, differently scented

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Any inherent errors in early pendulum clocks were smaller than other errors caused by factors such as temperature variation. In 1729 the Yorkshire carpenter and self-taught clockmaker

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in the 1930s. Prior to the advent of its military use, the wristwatch was typically only worn by women, but during World War I they became symbols of masculinity and bravado.

1422: 2021:. The following decades saw the development of quartz clocks as precision time measurement devices in laboratory settings—the bulky and delicate counting electronics, built with 1189:

The first innovations to improve on the accuracy of the hourglass and the water clock occurred in the 10th century, when attempts were made to slow their rate of flow using

1676:(the difference between the apparent solar time and the time given by a clock), publishing his results in 1665. The relationship enabled astronomers to use the stars to measure 2713:, which was replaced by a replica verge in 1956. It has no dial, as its purpose was to strike a bell. The wheels and gears are mounted in a 1.2 metres (3 ft 11 in) 2363:

and plastic parts enabled companies to reduce their work force. By the 1970s, many of those firms that maintained more complicated metalworking techniques had gone bankrupt.

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bell. His alarm was a timer that used a form of escapement to ring a small bell. This mechanism was the forerunner of the escapement device found in the mechanical clock.

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horologium verax valde et valeret plus quam astrolabium quantum ad horas capiendas vel aliud instrumentum astronomie, si quis hoc sciret facere secundum modum antedictum.

7619:. Corpus of mediaeval scientific texts sponsored jointly by the Mediaeval Academy of America and the University of Chicago; v. 2. Chicago: University of Chicago Press. 2489:

of the Cs atom. The caesium atomic clock maintained by NIST is accurate to 30 billionths of a second per year. Atomic clocks have employed other elements, such as

2153:, who devoted their careers to constructing high-quality chronometers and so-called 'deck watches', smaller versions of the chronometer that could be kept in a pocket. 505:. This sundial offered the innovation of the hours of the “horologium” throughout the day where before the Romans simply split the day into early morning and forenoon ( 7856: 2130:, a development that occurred during the 1690s. The concentric minute hand was an earlier invention, but a mechanism was devised by Quare that enabled the hands to be 2497:

vapor, offering greater stability (in the case of hydrogen clocks) and smaller size, lower power consumption, and thus lower cost (in the case of rubidium clocks).

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in 1919; his achievement removed much of the damping associated with mechanical devices and maximised the stability of the vibration's frequency. The first quartz

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in Athens once had a water clock, and a wind vane, as well as the nine vertical sundials still visible on the outside. In Greek tradition, clepsydrae were used in

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and aid navigation; most Aboriginal cultures had seasons that were well-defined and determined by natural changes throughout the year, including celestial events.

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were being used in China by the 6th century. In the medieval period, Islamic water clocks were unrivalled in their sophistication until the mid-14th century. The

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Pogo, A (1935). "Gemma Frisius, His Method of Determining Differences of Longitude by Transporting Timepieces (1530), and His Treatise on Triangulation (1533)".

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were first used in China around the 6th century, mainly for religious purposes, but also for social gatherings or by scholars. Due to their frequent use of

17: 2196:, or 'wristlets' were practical, as they freed up one hand that would normally be used to operate a pocket watch, and became standard equipment. The demands of 1856:

published in 1714. Huygens built the first sea clock, designed to remain horizontal aboard a moving ship, but that stopped working if the ship moved suddenly.

1477:

described a weight-driven clock with a verge-and-foliot escapement, a striking train of gears, an alarm, and a representation of the Moon's phases in his book

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as they moved across the sky. Devices and methods for keeping time have gradually improved through a series of new inventions, starting with measuring time by

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The History of Science and Technology: A Browser's Guide to the Great Discoveries, Inventions, and the People Who Made Them, From the Dawn of Time to Today

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being one of the few people recorded as having a way to measure time during the day, which was divided into seven parts using the position of the Sun.

3282: 881: 1447:, made in 1524. By 1500, the use of the foliot in clocks had begun to decline. The oldest surviving spring-driven clock is a device made by Bohemian 1045: 528:; an alternative theory proposes that a Damascus sundial measuring in polar time can be dated to 1372. European treatises on sundial design appeared 124:

In medieval Europe, purely mechanical clocks were developed after the invention of the bell-striking alarm, used to signal the correct time to ring

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degrees. And Isaiah the prophet cried unto the Lord: and he brought the shadow ten degrees backward, by which it had gone down in the dial of Ahaz.

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was a synthesis of earlier ideas from European and Islamic science. Mechanical clocks were a major breakthrough, one notably designed and built by

1326: 133: 1354:, dating from about 1386, is one of the oldest working clocks in the world, and may be the oldest; it still has most of its original parts. The 5813: 5656: 3290: 2420: 7738: 521:, sundials were developed during the 13th century with scales that showed equal hours. The first based on polar time appeared in Germany 2404: 1497:

is thought to have first realized that the pendulum could be used as an accurate timekeeper after watching the motion of suspended lamps at

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Error factors in early pendulum clocks included temperature variation, a problem tackled during the 18th century by the English clockmakers

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von Lieven, Alexandra (2016). "The Movement of Time. News from the "Clockmaker" Amenemhet". In Landgráfová, Renata; Mynářová, Jana (eds.).

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had made an inventory in 1572 of the watches she acquired, all of which were considered to be part of her jewellery collection. The first

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device was built in 1948 at NIST. Although less accurate than existing quartz clocks, it served to prove the concept of an atomic clock.

1777:, connected so as to maintain the overall length of the pendulum when it is heated or cooled by its surroundings. In 1781 the clockmaker 326: 2477:(SI) standardized its unit of time, the second, on the properties of caesium. The SI defined the second as 9,192,631,770 cycles of the 2100:

were inaccurate, as their size precluded them from having sufficiently well-made moving parts. Unornamented watches began to appear in

802:(1203). A sophisticated water-powered astronomical clock was described by Al-Jazari in his treatise on machines, written in 1206. This 1802:

that expands very little, largely eliminated the need for earlier inventions designed to compensate for the variation in temperature.

1628:. The anchor escapement originated with Hooke, although it has been argued that it was invented by Clement, or the English clockmaker 353: 3874: 1318:

had been replaced by one with an escapement. The foliot was first illustrated by Dondi in 1364, and mentioned by the court historian

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and gives the Moon's age; within a zodiacal scale are two concentric rings that show the relative positions of the Sun and the Moon.

244:, which can be accurate to a few billionths of a second per year and are used to calibrate other clocks and timekeeping instruments. 2111:(or hairspring). Invented separately in 1675 by Huygens and Hooke, it enabled the oscillations of the balance wheel to have a fixed 1990:, an electrical driven pendulum clock designed in 1921, was the first clock to be a more accurate timekeeper than the Earth itself. 206:

to anyone who could discover a way to determine longitude, Harrison built a succession of accurate timepieces, introducing the term

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Time's Pendulum: From Sundials to Atomic Clocks, the Fascinating History of Timekeeping and How Our Discoveries Changed the World

2575: 2550: 968: 3686: 2044: 225:, became popular after World War I, in variations including non-magnetic, battery-driven, and solar powered, with quartz, 5694: 1997:

was invented in 1912. An electrical oscillator was first used to sustain the motion of a tuning fork by the British physicist

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by al‐Farisi is the earliest surviving machine with its gears still intact. Openings on the back of the astrolabe depict the

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The most famous example of a timekeeping device during the medieval period was a clock designed and built by the clockmaker

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The Book of Knowledge of Ingenious Mechanical Devices (Kitab fi Ma'rifat al-Hiyal al-Handasiyya) by ibn al-Razzaz al-Jazari

1298: 143:, which established basic clock design for the next 300 years. Minor developments were added, such as the invention of the 6411: 4327: 2321:, an example being a Patek Philippe ref. 1518, introduced in 1941, possibly the most complicated wristwatch ever made in 2298:, first introduced with limited success in the 18th century, was reintroduced in the 1920s by the English watchmaker 150:

The next major improvement in clock building, from the 17th century, was the discovery that clocks could be controlled by

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candle being a means of determining time at night. Similar candles were used in Japan until the early 10th century.

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Mechanics of Pre-Industrial Technology: An Introduction to the Mechanics of Ancient and Traditional Material Culture

210:. The electric clock, invented in 1840, was used to control the most accurate pendulum clocks until the 1940s, when 7680: 2461: 1689: 2317:

The first battery-driven watches were developed in the 1950s. High quality watches were produced by firms such as

1967:

indefinitely, and was probably the first to use the invention as a method for accurately measuring frequency. The

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addressed the problem of the water in clepsydrae freezing in cold weather when he replaced the water with liquid

670:, dividing the power into unit impulses so that motion of the planets and stars could be duplicated. In 976, the 497:

The Romans inherited the sundial from the Greeks. The first sundial in Rome arrived in 264 BC, looted from

6844: 2762: 1453: 627: 1417–1379 BC). There are no recognised examples in existence of outflowing water clocks from ancient 8536: 6062: 1930:. He experimented with ways of regulating the electricity and his improved devices proved to be more reliable. 1530:

position—such as a pendulum or an extended spring—acts to return the object to that position, and causes it to

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in the 17th century, and was installed in London's Science Museum in 1884, where it continues to operate.

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was able to obtain the first of four clocks that measured in seconds, and in Nuremberg, the German clockmaker

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as an aid to navigation. The earliest unambiguous evidence of the use an hourglass appears in the painting

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An Egyptian method of determining the time during the night, used from at least 600 BC, was a type of

1829:, in which four ships were wrecked as a result of navigational mistakes, the British government offered a 8239: 8219: 8165: 8050: 7886: 7300: 2018: 606: 397: 7151: 6575: 5928: 5862: 5700:. Time and Frequency Division, National Institute of Standards and Technology. p. 5. Archived from 3661: 2107:

Dials that showed minutes and seconds became common after the increase in accuracy made possible by the

1010:(r. 871–889), who used six candles marked at intervals of one inch (25 mm), each made from 12 716:

both referred to water clocks that were used to enforce time limits or measure the passing of time. The

369: 7906: 7891: 7829: 7808: 2742: 2544: 2435: 1998: 1778: 1665: 1648: 1641: 1315: 195: 6666: 6381: 6284: 6051:"The Scent of Time. A Study of the Use of Fire and Incense for Time Measurement in Oriental Countries" 6021: 2302:. After he went bankrupt in 1929, restrictions on automatic watches were lifted and companies such as 8060: 7871: 6783: 6028: 5961: 2924: 2299: 2135: 1934: 1899: 1351: 1241: 7485: 6895:

Rich and Great: Studies in Honour of Anthony J. Spalinger on the Occasion of his 70th Feast of Thoth

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that lost or gained less than about six seconds per day. Proposals were examined by a newly created

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Large mechanical clocks were built that were mounted in towers so as to ring the bell directly. The

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wrote of his contemporaries that they were in the process of developing a form of mechanical clock.

288: 7735: 6759: 6434:; Parry, J. V. L. (1955). "An Atomic Standard of Frequency and Time Interval: A Cæsium Resonator". 2482: 2328:

The manual winding Speedmaster Professional or "Moonwatch" was worn during the first United States

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in 1336. By 1341, clocks driven by weights were familiar enough to be able to be adapted for grain

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or the force of gravity. The earliest depiction of a clock powered by a hanging weight is from the

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The idea of using atomic transitions to measure time was first suggested by the British scientist

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was about 11 feet (3.4 m) high. In 1235, a water-powered clock that "announced the appointed

8320: 8098: 8000: 7916: 7911: 7675: 7246: 7023: 7021:; Hall, R.G.; Essen, L.; Parry, J.V.L. (1958). "Frequency of Cesium in Terms of Ephemeris Time". 5630: 5523: 2905: 2693: 2329: 1993:

A succession of innovations and discoveries led to the invention of the modern quartz timer. The

1538:

on the physical characteristics of the oscillating system and not the starting conditions or the

1487:), written around 1565. Jesuit missionaries brought the first European clocks to China as gifts. 1372: 992: 795: 638:, perhaps from Mesopotamia, occurred as far back as the 2nd millennium BC, during the 7540: 3566: 2750: 2093: 2055: 1994: 1926:

but the disadvantage of its electrical properties varying according to the air temperature and

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Studies in Medieval Islamic Technology From Philo to Al-Jazari – from Alexandria to Diyar Bakr

5596: 4293: 1415:, who produced the earliest known drawings of a pendulum in 1493–1494, illustrated a fusee in 8473: 6963: 6661: 5864:

The Measure of All Things: The Seven-Year Odyssey and Hidden Error that Transformed the World

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that can be precisely controlled, properties that allow them to have a remarkable degree of

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timekeeping mechanism for the Salisbury Cathedral clock is lost, having been converted to a

1550: 1017: 8541: 8300: 8214: 8040: 7901: 7326: 7032: 6471: 6443: 5892:"A Schedule of Boundaries: An Exploration, Launched from the Water-Clock, of Athenian Time" 3182: 2608:, noted that the sundial is not a timekeeping device, as it could only "at best keep local 2325:, which fetched a world record price in 2016 when it was sold at auction for $ 11,136,642. 2283: 1923: 1814: 1715: 1403:. There is a fusee in the earliest surviving spring-driven clock, a chamber clock made for 890: 755: 547: 184: 50: 6597: 971:

constructed a variety of highly accurate astronomical clocks for use in their mosques and

303:

civilizations left no recorded history, little is known of their timekeeping methods. The

8: 8510: 8305: 8160: 8025: 7977: 7229:

Nelson, A. A. (1993). "The Moon Watch: a history of the Omega Speedmaster Professional".

7214:. Science and Civilization in China. Vol. 4. Cambridge: Cambridge University Press. 6413:

The Space of Time: a sensualist interpretation of time in Augustine, Confessions X to XII

5574:"Stainless Steel Patek Philippe Ref. 1518 Sells For Over $ 11,000,000 At Phillips Geneva" 5121: 2779: 2349: 2162: 2139: 1711: 1604: 1091: 1067: 1022: 937:

with geared mechanisms were made in Persia. Examples include those built by the polymath

490:

to derive the position of the Sun from data such as the hour of day and the geographical

401: 307:

calender monument is currently considered to be the oldest lunisolar calendar yet found.

268: 180: 151: 58: 54: 7846: 7330: 7036: 6447: 3176:"Architecture in the Service of Science: The Astronomical Observatories of Jai Singh II" 2932: 8485: 8259: 8183: 8113: 7706: 7573: 7423: 7350: 7316: 7288: 7280: 7193: 7092: 7080: 6827: 6819: 6692: 6570: 6459: 6227: 6206: 6149: 6092: 5911: 4493: 2746: 2511: 2423:(NIST)) changed the way it based the time standard of the United States from quartz to 2265: 2034: 2002: 1946: 1864: 1848: 1835: 1657: 1612: 1586: 1366: 1255:

1275 was one of the most important inventions in both the history of the clock and the

1150: 1078: 787: 741: 698: 667: 651: 175: 46: 3033: 794:

in Damascus was constructed by Muhammad al-Sa'ati, and was later described by his son

558:. The time was determined by observing particular stars as they crossed the meridian. 147:

in the early 15th century, which allowed small clocks to be built for the first time.

8333: 8198: 8015: 7713: 7687: 7661: 7642: 7620: 7610: 7592: 7577: 7565: 7527: 7517: 7492: 7480: 7466: 7445: 7427: 7415: 7392: 7385: 7369: 7354: 7342: 7292: 7272: 7215: 7185: 7158: 7111: 7084: 7048: 7018: 6999: 6989: 6948: 6929: 6899: 6878: 6861: 6851: 6831: 6811: 6769: 6741: 6720: 6699: 6673: 6647: 6623: 6582: 6556: 6535: 6513: 6481: 6417: 6398: 6388: 6365: 6341: 6315: 6290: 6269: 6248: 6210: 6198: 6159: 6135: 6125: 6111: 6084: 6032: 6005: 5984: 5965: 5935: 5873: 5846: 4828: 4497: 3416: 2728: 2526: 2370: 1806: 1770: 1755: 1737: 1620: 1607:

was the most productive era in timekeeping. The first invention of this type was the

1412: 1202: 1194: 1074: 1014:

of wax, and made to be 12 centimetres (4.7 in) high and of a uniform thickness.

1007: 849: 763: 679: 655: 569:

built in 1727 by Jai Singh II includes the Vrihat Samrat Yantra, 88 feet (27 m) tall

404:

in 2013. Obelisks could indicate whether it was morning or afternoon, as well as the

155: 7736:

Relativity Science Calculator – Philosophic Question: are clocks and time separable?

7096: 6334: 6107:

The Trail of Time: Shih-chien Ti Tsu-chi: Time Measurement with Incense in East Asia

2340:

mission and was the first watch worn by an astronaut walking on the Moon during the

1919: 1391:(which although invented in the 15th century can be documented no earlier than 121:, invented in Europe, was one of the few reliable methods of measuring time at sea. 8478: 8224: 8203: 8155: 8118: 7931: 7632: 7555: 7334: 7264: 7138: 7134: 7076: 7040: 6803: 6755: 6619: 6495: 6463: 6451: 6190: 6174: 6079: 6074: 6066: 5903: 5701: 4485: 2944: 2706: 2560: 2449: 2261: 2116: 1960: 1786: 1719: 1673: 1396: 1284: 1245: 1224: 1003: 717: 129: 34: 5934:. Translated by Keynes, Simon; Lapidge, Michael. London; New York: Penguin Books. 5767: 5718: 3744: 1813:, with a day divided into 10 hours of 100 minutes each. A clock in the 1810: 8209: 8188: 8020: 7992: 7757: 7742: 7655: 7636: 7586: 7511: 7460: 7439: 7363: 7242: 7209: 7105: 7060: 6983: 6942: 6735: 6714: 6641: 6550: 6507: 6503: 6475: 6359: 6309: 6263: 6153: 6129: 6105: 5999: 2605: 2516: 2356: 2322: 2295: 2257: 2150: 2014: 1956: 1942: 1907: 1830: 1695:

Other innovations in timekeeping during this period include the invention of the

1685: 1594: 1494: 1404: 1311: 1275: 1133: 456: 409: 405: 338: 203: 163: 4590: 4578: 3453:

see Hero's books: Pneumatica (Πνευματικά), Automata, Mechanica, Metrica, Dioptra

2632: – 184 BC) shows that sundials were familiar to the Romans: 2227: 1732:

were the early centres of clockmaking in France, and French clockmakers such as

1279: 975:, such as the astrolabic clock by Ibn al-Shatir in the early 14th century. 834:; time was measured by means of powdered incense burnt along a pre-measured path 438:

during the 8th century BC, is recorded as being healed by the prophet

325:

understood the movement of objects in the sky well, and used their knowledge to

8505: 8264: 8254: 8193: 8150: 7982: 7972: 7941: 7841: 7813: 7606: 7435: 7408:

Antiquarian Horology and the Proceedings of the Antiquarian Horological Society

7205: 6794: 6527: 6499: 6355: 6305: 6131:

Over the Edge of the World: Magellan's Terrifying Circumnavigation of the Globe

5887: 5442: 3099:

Daily Life in Ancient Rome: The People and the City at the Height of the Empire

2758: 2754: 2674: 2565: 2521: 2466: 2318: 2197: 2174: 2122: 2108: 2084: 2080: 2068: 2006: 1911: 1843: 1681: 1653: 1608: 1589:

in 1656. His invention increased the accuracy of clocks more than sixty-fold; (

1582: 1568: 1559: 1506: 1498: 1470: 1431: 1319: 1137: 1111: 838: 791: 749: 635: 475: 171: 106: 7747: 7646: 7044: 4450: 2438:

that there was a practical method for measuring time in this way. A prototype

2142:, is credited with the design of the first jewel bearings in watches in 1704. 1236: 1132:. The origin of the word is not known for certain; it may be a borrowing from 778:

clock was rather invented by the great mathematician, physicist, and engineer

8530: 8392: 8343: 8328: 8274: 8045: 7881: 7876: 7792: 7624: 7569: 7531: 7507: 7419: 7406:

Ronalds, Beverley F. (2015). "Remembering the first battery-operated clock".

7346: 7276: 7189: 7052: 6933: 6815: 6402: 6329: 6202: 6088: 6046: 5949: 5869: 2570: 2555: 2411: 2178: 2072: 1976: 1968: 1915: 1871: 1766: 1751: 1743: 1733: 1677: 1463: 1440: 1290: 860: 831: 663: 647: 639: 620: 261: 191: 114: 110: 84: 7088: 7003: 6865: 5930:

Alfred the Great: Asser's Life of King Alfred and other contemporary sources

2238: 459:

period describes the lengths of shadows at different times of the year. The

8490: 8377: 8372: 8367: 8354: 8093: 7064: 6839: 5794: 4832: 2909: 2601: 2486: 2424: 2400: 2385: 2287: 2193: 2010: 1980: 1785:

pendulum by using a bob made from a glass jar of mercury—a liquid metal at

1707: 1629: 1443:

was paid for making what is thought to have been the earliest example of a

1419: 1500, a quarter of a century after the coiled spring first appeared. 1083: 999: 988: 984: 803: 671: 518: 487: 382: 334: 330: 304: 241: 211: 62: 7365:

Eastern Magnificence and European Ingenuity: Clocks of Late Imperial China

6914: 5907: 1458:

in 1525. The first person to suggest travelling with a clock to determine

8500: 8495: 8140: 8123: 8055: 8035: 7921: 7803: 7338: 6765: 6637: 6477:

Of Time, Passion, and Knowledge: Reflections on the Strategy of Existence

6431: 6265:

Orrery: A Story of Mechanical Solar Systems, Clocks, and English Nobility

5983:(7th ed.). London: Eyre & Spottiswoode; E. & F.N. Spon Ltd. 4536: 2457: 2453: 2431: 2397: 2389: 2360: 2269: 2185: 2097: 2022: 1964: 1700: 1436: 1095: 1011: 972: 962: 810:

and the time both by day and by night" stood in the entrance hall of the

807: 725: 687: 675: 643: 628: 602: 590: 452: 310: 226: 94: 80: 66: 7605: 7197: 7173: 6231: 6219: 4031: 2290:

watch, and the design of watches during the 1920s was influenced by the

826: 654:), created the first balance clepsydra, with standard positions for the 128:

bells. The weight-driven mechanical clock controlled by the action of a

8515: 8468: 8452: 8338: 8244: 8065: 7926: 7896: 7834: 7560: 7174:"Miraculous Syllogisms: Clocks, Faith and Reason in Paradiso 10 and 24" 6915:"NIST Primary Frequency Standards and the Realization of the SI Second" 6552:

Manufacturing Time: Global Competition in the Watch Industry, 1795-2000

6178: 6096: 6050: 4290:"Oldest Working Clock, Frequently Asked Questions, Salisbury Cathedral" 2933:"Astronomical Time versus Social Time: A Case Study from Ancient Egypt" 2609: 2580: 2539: 2464:

in London. It was calibrated by the use of the astronomical time scale

2366: 2311: 2202: 2127: 1790:

metals to be thermally coupled more tightly. In 1895, the invention of

1526:, in which the restoring force acting on an object moved away from its 1388: 1384: 1380: 1214: 846: 842: 779: 767: 759: 713: 709: 539: 427: 280: 257: 234: 230: 218: 144: 98: 29: 7284: 7250: 6913:

Lombardi, Michael A.; Heavner, Thomas P.; Jefferts, Steven R. (2007).

6823: 6788: 6194: 5915: 5891: 5737: 4566: 4419: 4380: 4378: 3353: 2948: 1213:

illustrated a device that was the step towards the development of the

1101: 8412: 8249: 8133: 8108: 8088: 8005: 7957: 7951: 7936: 7701: 6768:(1st (reprinted) ed.). Dordrecht: D. Reidel Publishing Company. 6455: 4265: 2906:"One of world's oldest sun dial dug up in Kings' Valley, Upper Egypt" 2775: 2478: 2341: 2189: 2112: 1953: 1839: 1747: 1539: 1531: 1459: 1343: 1166: 1053: 1040: 934: 912: 771: 740:

included. There is strong evidence that the 1st century BC

682:. A water-powered astronomical clock tower was built by the polymath 586: 555: 460: 314: 284: 167: 166:

had investigated the regular swing of the pendulum, discovering that

118: 102: 38: 6893: 6070: 5325: 1986:

The most accurate pendulum clocks were controlled electrically. The

1383:

in the early 15th century—a device first used in locks and for

214:

became the basis for the precise measurement of time and frequency.

41:, nowadays often used symbolically to represent the concept of time. 8447: 8427: 8269: 8175: 8075: 7866: 7861: 7321: 7268: 6807: 6694:

Wings of Madness: Alberto Santos-Dumont and the Invention of Flight

5262: 4489: 4431: 4375: 4363: 4127: 3003: 3001: 2710: 2494: 2490: 2434:

in 1879, although it was only in the 1930s with the development of

2337: 2291: 2166: 2131: 2115:. The invention resulted in a great advance in the accuracy of the 1927: 1882:

Harrison made two watches, "H4" and "H5". Eric Bruton, in his book

1853: 1522:

The first accurate timekeepers depended on the phenomenon known as

1502: 1491: 1400: 1271: 1264: 1190: 853: 693: 686:

in 1088, which featured the first known endless power-transmitting

491: 464: 431: 420: 318: 300: 296: 222: 221:, which had been recognised as a valuable military tool during the 159: 125: 70: 7231:

Bulletin of the National Association of Watch and Clock Collectors

6179:"Changing Times: The Mechanical Clock In Late Medieval Literature" 5695:"Time and frequency measurement at NIST: The first 100 years" 4241: 4178: 2218: 381:

The first devices used for measuring the position of the Sun were

8442: 8432: 8362: 8234: 8145: 8010: 3977: 3413:

The Antikythera Mechanism, the first mechanical cosmos (in Greek)

2622: 2439: 1838:. Among the many people who attempted to claim the prize was the 1057: 958: 815: 683: 659: 617: 570: 551: 543: 498: 486:, written in the 2nd century AD, used an early form of 479: 386: 358: 292: 240:

The most accurate timekeeping devices in practical use today are

76: 7541:"The First Electric Clock: Alexander Bain's gold contact system" 7305:"Dawes Review 5: Australian Aboriginal Astronomy and Navigation" 6494: 5766:. National Institute of Standards and Technology. Archived from 4596: 4584: 4554: 2998: 1859: 1270:

At around the same time as the invention of the escapement, the

1127: 1121: 1115: 1043:

described four different designs for a candle clock in his book

8437: 8387: 8382: 7211:

Physics and Physical Technology, Part 2: Mechanical Engineering

5527: 5151: 3224: 2307: 1972: 1938: 1799: 1636: 1181:

Water clock (representing a clock at the royal court in Paris,

954: 733: 573:. It can tell local time to an accuracy of about two seconds. 566: 502: 439: 7125:

Meskens, Ad (1992). "Michiel Coignet's Nautical Instruction".

4713: 4602: 4308: 8417: 8229: 8128: 8083: 7638:

The Comedies of Plautus, Translated Into Familiar Blank Verse

6846:

Revolution in Time: Clocks and the Making of the Modern World

5923: 3831: 2442: 2374: 2345: 2303: 1894: 1795: 1791: 1729: 1725: 1479:

The Brightest Stars for the Construction of Mechanical Clocks

1444: 1307: 1141: 950: 745: 721: 435: 279:, to determine time. According to the historian Eric Bruton, 6740:. San Rafael, California: Morgan & Claypool Publishers. 6512:(Advanced ed.). Cambridge: Cambridge University Press. 5226: 4846: 4614: 4516: 4353: 4351: 4349: 3965: 3893: 3564: 3341: 2661: Shrunk up with hunger, creep along the streets. 1773:, which used at least three metals of different lengths and 8422: 8407: 8397: 7851: 7788: 6873:

Lankford, John (1997). "Time and Timekeeping Instruments".

6361:

Sky and Ocean Joined: The U.S. Naval Observatory, 1830–2000

5363: 5180: 5178: 4397: 4395: 4393: 4231: 4229: 3929: 3704: 3641: 3605: 3365: 3063: 2714: 2377:, were introduced to the market in the early 21st century. 2333: 2181:

to design a watch that could be useful during his flights.

2092:

The first wristwatches were made in the 16th century.

1782: 1399:, which first originated from medieval weapons such as the 1162: 775: 729: 276: 7857:

International Earth Rotation and Reference Systems Service

6985:

The Quantum Beat: The Physical Principles of Atomic Clocks

6898:. Prague: Charles University in Prague. pp. 207–231. 5782: 5274: 4982: 4761: 4662: 4054: 4052: 3783: 3546: 3524: 3522: 3260: 3236: 73:. Oscillating timekeepers are used in modern timepieces. 8402: 7516:(4th ed.). Hillside, New Jersey: Enslow Publishers. 7462:

The Golden Peaches of Samarkand: A Study of T'ang Exotics

5375: 5291: 5289: 5090: 4346: 4214: 4079: 3917: 3629: 3534: 3212: 3200: 2876: 2874: 2657: The town's so full of these confounded dials, 762:

described a water clock that employed both segmental and

373:

Vrihat Samrat Yantra, 88 feet (27 m) tall sundial at the

272: 229:

and plastic parts all introduced. Since the early 2010s,

6668:

A History of Engineering in Classical and Medieval Times

6218:

Brown, David; Fermor, John; Walker, Christopher (1999).

5611: 5238: 5214: 5202: 5190: 5175: 5163: 5139: 5102: 5078: 5066: 4994: 4947: 4945: 4906: 4691: 4689: 4638: 4390: 4226: 4103: 3941: 3483: 3317: 2808: 998:

The invention of the candle clock was attributed by the

7017: 6912: 5800: 5743: 5411: 5054: 5042: 5006: 4870: 4858: 4701: 4650: 4504: 4144: 4142: 4049: 3989: 3716: 3593: 3519: 2861: 2859: 2832: 2637: How to distinguish hours! Confound him too, 2145:

Other notable 18th-century English horologists include

1484:

Al-Kawākib al-durriyya fī wadh' al-bankāmat al-dawriyya

6850:. Cambridge, Massachusetts: Harvard University Press. 5541: 5399: 5313: 5301: 5286: 5250: 4809: 4785: 4674: 4407: 4253: 4190: 4115: 4069: 4067: 4032:

Thorndike, de Sacro Bosco & Robertus Anglicus 1949

3843: 3807: 3394: 3392: 3305: 3248: 3141: 3051: 2986: 2871: 2820: 1149:('bell'). 7th century Irish and 9th century 907:

11th century description of a geared astrolabe; (

7368:. Ann Arbor, Michigan: University of Michigan Press. 7309:

Publications of the Astronomical Society of Australia

6598:"Origin and Evolution of the Anchor Clock Escapement" 6480:. Princeton, New Jersey: Princeton University Press. 5553: 5504: 5492: 5480: 5468: 5387: 5030: 5018: 4942: 4930: 4918: 4894: 4797: 4773: 4749: 4737: 4725: 4686: 4626: 4202: 4166: 4154: 4091: 4013: 3795: 3567:"Visualizing Video Streams using Sand Glass Metaphor" 3507: 3105: 2974: 5978: 5674: 5456: 5331: 5268: 4882: 4572: 4437: 4425: 4384: 4369: 4247: 4184: 4139: 4133: 4037: 4001: 3983: 3953: 3905: 3855: 3819: 3759: 3617: 3581: 3329: 2962: 2856: 2649: This dial told me when 'twas proper time 2645: My belly was my sun-dial: one more sure, 2396:) and Jack Parry standing next to the world's first 1714:

that chimes the number of hours or minutes, and the

1501:. In 1582, he investigated the regular swing of the 1482: 1251:

The invention of the verge and foliot escapement in

7591:. Cambridge; New York: Cambridge University Press. 7241: 6964:"An astronomical inscription on the Berlin merkhet" 5816:. National Research Council Canada. January 9, 2020 4064: 3771: 3471: 3459: 3389: 3359: 3129: 3117: 3075: 3013: 2844: 2796: 1102:

History of early oscillating devices in timekeepers

65:, to mechanical clocks, and eventually repetitive, 7787: 7708:How the Catholic Church Built Western Civilization 7705: 7679: 7660:. Philadelphia: University of Pennsylvania Press. 7657:Medieval Robots: Mechanism, Magic, Nature, and Art 7484: 7384: 7184:(117). The Johns Hopkins University Press: 59–84. 7150: 6843: 6787: 6691: 6665: 6574: 6387:. Brattleboro, Vermont: The Stephen Greene Press. 6380: 6333: 6240: 6055:Transactions of the American Philosophical Society 6020: 5979:Baillie, G.H.; Clutton, C.; Ilbert, C.A. (1969) . 5953: 5927: 5861: 5845:. Cedar Rapids, Iowa: Knowledge House Publishers. 4965:"Harrison's eight-day wooden clock movement, 1715" 3495: 3377: 2653: But now-a-days, why, even when I have, 2348:produced the world's first quartz wristwatch, the 1140:, and can perhaps be traced to the post-classical 957:astrolabe (which also acts as a calendar) made in 7588:The Lord of Uraniborg: a biography of Tycho Brahe 6303: 6217: 5981:Britten's Old Clocks and Watches and their Makers 4560: 3230: 3007: 2886: 2641: To cut and hack my days so wretchedly 1975:were discovered by the French physicist brothers 1611:, which was designed and built by Dutch polymath 1046:Book of Knowledge of Ingenious Mechanical Devices 991:, written in 520 by You Jianfu, who wrote of the 247: 237:have become the most common timekeeping devices. 8528: 6172: 4271: 3653: 3565:Chang, Edward; Lu, Yung-Hsiang (December 1996). 2774:Quartz resonators can vibrate with very a small 2481:which corresponds to the transition between two 1933:In 1840 the Scottish clock and instrument maker 1902:'s early electromagnetic clocks, from the 1840s 978: 7505: 5631:"Milestones:Electronic Quartz Wristwatch, 1969" 5157: 1805:Between 1794 and 1795, in the aftermath of the 1692:, so that the clock indicated true solar time. 1512: 1217:. Another forerunner of the escapement was the 517:According to the German historian of astronomy 333:were used to mark shorter periods of time; the 7315:(33, E039). Cambridge University Press: 1–39. 6612:Hellemans, Alexander; Bunch, Bryan H. (2004). 6611: 5758: 5756: 5754: 5752: 4320: 3347: 3291:National Institute of Standards and Technology 2421:National Institute of Standards and Technology 1370:Fusee for clocks (Leonardo da Vinci) from his 1278:used clock imagery to depict the souls of the 291:, used for seasonal and annual events such as 170:was only dependent on length, not weight. The 158:had produced the earliest known drawings of a 7773: 7754:of Islamic time-keeping inventions (YouTube). 7616:The Sphere of Sacrobosco and its Commentators 6569: 4522: 4284: 4282: 4280: 3647: 2635:The gods confound the man who first found out 1098:, usually represented as a bearded, old man. 1086:, then an entirely European and Western art. 419: BC that was similar in shape to a bent 348: 4534: 3687:"Inventory no. 48213 – Former Display Label" 3662:"Engineering in Arabic-Islamic Civilisation" 2655:I can't fall to, unless the sun gives leave. 2156: 1809:, the French government mandated the use of 1781:compensated for temperature variation in an 1672:Huygens first used a clock to calculate the 941:in the 11th century and the astronomer 666:regulated the power of the water driving an 550:was created using two merkhets aligned with 317:(base-20) counting system when dealing with 7251:"The Water Clock in the Tower of the Winds" 7065:"The Evolution of the Quartz Crystal Clock" 6509:The Mechanical Universe: Mechanics and Heat 6189:(4). Penn State University Press: 351–375. 5749: 2028: 1218: 1144: 800:On the Construction of Clocks and their Use 766:. Islamic water clocks, which used complex 605:, is from the tomb inscription of an early 442:and asks for a sign that he would recover: 7780: 7766: 7748:Ancient Discoveries Islamic Science Part 4 7712:. Washington, D.C.: Regnery Publications. 7641:. London: T. Becket & P. A. de Hondt. 7387:Mapping Time: The Calendar and its History 6891: 6577:Islamic Technology: an illustrated history 6430: 6282: 5902:(2). Cambridge University Press: 157–168. 5788: 5436: 4957: 4314: 4277: 3666:History of Science and Technology in Islam 3435: 3218: 3206: 2745:circuit; the gravity pendulum; the quartz 1624:for King's College, Cambridge, now in the 1603:The period when clocks were controlled by 1462:, in 1530, was the Dutch instrument maker 601:The oldest description of a clepsydra, or 426:A sundial is referred to in the Bible, in 7559: 7320: 6754: 6581:. Cambridge: Cambridge University Press. 6548: 6416:. Leiden; Boston (Massachusetts): Brill. 6409: 6314:. Cambridge: Cambridge University Press. 6110:. Cambridge: Cambridge University Press. 6078: 5686: 5439:"How World War I Changed Watches Forever" 5432: 5430: 5428: 5426: 5381: 3789: 3659: 3489: 3323: 3096: 2651:To go to dinner, when I had aught to eat— 2456:atom, was built by the English physicist 2177:, asked his friend the French watchmaker 1718:, invented around 1675 by the astronomer 856:(made from different recipes) were used. 821: 389:. The oldest known sundial dates back to 61:processes, such as the flow of liquid in 8311:International Commission on Stratigraphy 7631: 7434: 7382: 7059: 6961: 6872: 6716:Greek and Roman Technology: A Sourcebook 6712: 6595: 6124: 5692: 5351:. Fondation de la Haute Horlogerie. 2019 5232: 5220: 5208: 5196: 5184: 5169: 5145: 5108: 5084: 5072: 4852: 4767: 4707: 4668: 4656: 4644: 4620: 4401: 4235: 4058: 3935: 3867: 3813: 3599: 3558: 3371: 3173: 3147: 3069: 2930: 2880: 2826: 2727:The clock was converted to pendulum-and- 2384: 1893: 1858: 1742: 1647: 1421: 1365: 1235: 1176: 1016: 825: 692: 631:, but written references have survived. 580: 368: 352: 251: 28: 7538: 7479: 7458: 7405: 7204: 7124: 7103: 6686: 6526: 6018: 5711: 5635:Engineering and Technology History Wiki 5571: 5437:Pennington, Cole (September 24, 2019). 5417: 5393: 5345:"Nicolas Fatio de Duillier (1664–1753)" 5096: 5060: 5048: 5012: 4876: 4680: 4510: 4220: 4160: 4109: 4085: 4019: 3899: 3849: 3837: 3801: 3552: 3410: 3311: 3277: 3275: 3266: 3254: 3242: 3111: 2980: 2865: 2647:Truer, and more exact than any of them. 2576:Timeline of time measurement inventions 2551:History of timekeeping devices in Egypt 2009:in 1921, and in October 1927 the first 1906:In 1815, the prolific English inventor 1710:, a London clock-maker, in 1676 of the 412:. A kind of shadow clock was developed 174:, designed and built by Dutch polymath 18:Timeline of time measurement technology 14: 8529: 7653: 7584: 7361: 7299: 7228: 7145: 6838: 6470: 6328: 6238: 6103: 6045: 5617: 5559: 5547: 5510: 5498: 5486: 5474: 5462: 5423: 5405: 5369: 5337: 5319: 5307: 5295: 5280: 5256: 5244: 5036: 5024: 5000: 4988: 4951: 4936: 4924: 4912: 4821: 4815: 4791: 4695: 4632: 4413: 4259: 4208: 4196: 4148: 4097: 4043: 3995: 3923: 3911: 3734: 3635: 3623: 3611: 3587: 3540: 3528: 3513: 2968: 2850: 2814: 2802: 2355:During the 1970s, the introduction of 1039:The 12th century Muslim inventor 7761: 7700: 7686:. New York: Oxford University Press. 7682:Medieval Technology and Social Change 7674: 7391:. New York: Oxford University Press. 7171: 6981: 6940: 6875:History of Astronomy: an Encyclopedia 6733: 6378: 6261: 6148: 5997: 5948: 5922: 5886: 5859: 5840: 5744:Lombardi, Heavner & Jefferts 2007 5572:Touchot, Arthur (November 12, 2016). 4900: 4888: 4864: 4803: 4779: 4755: 4743: 4731: 4719: 4608: 4469: 4357: 4172: 4121: 4007: 3959: 3947: 3861: 3825: 3765: 3710: 3660:Hill, Donald R.; al-Hassan, Ahmad Y. 3335: 3135: 3123: 3092: 3090: 3081: 3057: 3019: 2992: 2892: 2838: 2643:Into small portions—When I was a boy, 2452:based on a certain transition of the 2310:produced the first ever non-magnetic 1820: 1361: 6782: 6660: 6636: 6354: 5764:"The "Atomic Age" of Time Standards" 5680: 5657:"Alarm Clocks from the Black Forest" 4475: 4073: 3971: 3777: 3722: 3501: 3477: 3465: 3398: 3383: 3272: 3031: 2659:The greatest part of its inhabitants 2587: 2306:were able to produce them. In 1930, 2165:(1870–1871), and by the time of the 1706:, the invention by either Barlow or 1314:, and by 1344 the clock in London's 983:One of the earliest references to a 701:in Athens (1st century BC) 202:, after which governments offered a 7110:. Oxford: Oxford University Press. 6340:. Oxford: Oxford University Press. 6004:. Oxford: Oxford University Press. 3679: 3293:Physics Laboratory. August 12, 2009 2931:Gautschy, Rita (January 24, 2018). 2639:Who in this place set up a sundial, 2448:The first accurate atomic clock, a 2013:was described by Joseph Horton and 2005:was built by the American engineer 1817:kept decimal time as late as 1801. 1699:for striking clocks by the English 24: 7465:. University of California Press. 7441:Fire: Servant, Scourge, and Enigma 7081:10.1002/j.1538-7305.1948.tb01343.x 7075:(3). New York: AT&T: 510–588. 5719:"Atomic ticker clocks up 50 years" 5597:"The Patek Philippe 1518 In Steel" 5594: 5332:Baillie, Clutton & Ilbert 1969 5269:Baillie, Clutton & Ilbert 1969 4573:Baillie, Clutton & Ilbert 1969 4438:Baillie, Clutton & Ilbert 1969 4426:Baillie, Clutton & Ilbert 1969 4385:Baillie, Clutton & Ilbert 1969 4370:Baillie, Clutton & Ilbert 1969 4248:Baillie, Clutton & Ilbert 1969 4185:Baillie, Clutton & Ilbert 1969 4134:Baillie, Clutton & Ilbert 1969 3984:Baillie, Clutton & Ilbert 1969 3181:. Jantarmantar.org. Archived from 3087: 1889: 1517: 748:, a practise later adopted by the 25: 8563: 8031:Discrete time and continuous time 7729: 6877:. Hoboken: Taylor & Francis. 6243:The History of Clocks and Watches 3691:History of Science Museum, Oxford 2208: 1884:The History of Clocks and Watches 1697:rack and snail striking mechanism 1373:Treatise of statics and mechanics 925:History of Science Museum, Oxford 385:, which later developed into the 7956: 7950: 7487:Great Ages of Man: Ancient China 7383:Richards, Edward Graham (1999). 6947:. New York: Garland Publishing. 6928:(4). NCSL International: 74–89. 6596:Headrick, Mark V. (April 2002). 6555:. New York: The Guilford Press. 6220:"The Water Clock in Mesopotamia" 5814:"What is a Cesium Atomic Clock?" 5806: 5649: 5623: 5588: 5565: 5516: 5114: 4537:"No. 1005: Another Take on Time" 4528: 4443: 3450: 2768: 2734: 2721: 2699: 2685: 2380: 2246: 2237: 2226: 2217: 2054: 2043: 1945:pendulum. The English scientist 1758:shown in the background (1768), 1567: 1558: 1549: 1299:tower clock of Norwich Cathedral 889: 880: 724:is supposed to have invented an 69:processes, such as the swing of 7256:American Journal of Archaeology 7153:Watches: the ultimate accessory 6713:Humphrey, John William (1998). 6646:. London; New York: Routledge. 6640:(2016) . King, David A. (ed.). 4969:Science Museum Group Collection 3728: 3444: 3429: 3404: 3360:Noble & de Solla Price 1968 3167: 3153: 3025: 3008:Brown, Fermor & Walker 1999 2937:Journal of Skyscape Archaeology 2666: 2615: 2272:; a digital quartz wristwatch ( 2256:Modern wristwatches: a Harwood 1910:produced the forerunner of the 1231: 1172: 943:Muhammad ibn Abi Bakr al‐Farisi 732:balls cascading noisily onto a 576: 472: 3rd century BC 267:Ancient civilizations observed 8104:History of timekeeping devices 7157:. London; New York: Miller's. 7139:10.1080/00253359.1992.10656406 6789:"The Astronomy of the Mamluks" 6364:. Cambridge University Press. 6063:American Philosophical Society 3415:. Athens: Canto Mediterraneo. 3161:"Largest sundial world record" 2594: 1922:, a high voltage battery with 1597:'s portrait of Huygens (1671). 1223:, which used an early kind of 736:platter to wake his students. 248:Continuous timekeeping devices 13: 1: 7513:Amateur Astronomer's Handbook 7491:. New York: Time-Life Books. 7069:Bell System Technical Journal 6605:IEEE Control Systems Magazine 6532:Pietro et Ambrogio Lorenzetti 5956:Skywatchers of Ancient Mexico 5832: 5126:American Institute of Physics 4561:Cotterell & Kamminga 1990 4329: 3231:Cotterell & Kamminga 1990 2626: 2475:International System of Units 2286:influenced the design of the 2273: 2161:Watches were worn during the 2101: 2067:An illustration of a Huygens 1827:Scilly naval disaster of 1707 1661: 1426:The so-called 'Henlein Watch' 1416: 1408: 1392: 1330: 1302: 1252: 1182: 1032: 979:Candle clocks and hourglasses 946: 916: 871: 624: 610: 529: 522: 413: 400:), and was discovered in the 390: 200:Scilly naval disaster of 1707 137: 87: 7654:Truitt, Elly Rachel (2015). 7609:; de Sacro Bosco, Johannes; 6155:Eight Eurocentric Historians 4272:Bradbury & Collette 2009 3741:International Watch Magazine 2789: 2462:National Physical Laboratory 2417:National Bureau of Standards 2405:National Physical Laboratory 2188:, wristwatches were used by 1682:clock that showed solar time 1513:Era of precision timekeeping 1336:Giovanni Dondi dell'Orologio 7: 8051:Gravitational time dilation 7887:Barycentric Coordinate Time 7104:Matthys, Robert J. (2004). 6379:Dolan, Winthrop W. (1975). 6027:(1st ed.). San Diego: 6001:Seven Tales of the Pendulum 5158:Sidgwick & Muirden 1980 3097:Carcopino, Jérôme. (1940). 2500: 2094:Elizabeth I of England 2019:Bell Telephone Laboratories 1941:describing a clock with an 1918:clock. It was powered with 1870:In 1715, at the age of 22, 1652:Detail from the face of an 1483: 1259:. It was the first type of 1063:Allegory of Good Government 1028:Allegory of Good Government 658:. In 721 the mathematician 595:Oriental Institute, Chicago 321:to produce a 360-day year. 283:is likely to have been the 260:in southern England on the 10: 8568: 7907:Geocentric Coordinate Time 7892:Barycentric Dynamical Time 7830:Coordinated Universal Time 7585:Thoren, Victor E. (1990). 7362:Pagani, Catherine (2001). 6988:. New York, NY: Springer. 6573:; Hill, Donald R. (1986). 6224:Archiv für Orientforschung 6019:Barnett, Jo Ellen (1999). 5998:Baker, Gregory L. (2011). 5843:Miracle of Islamic Science 3411:Moussas, Xenophon (2018). 3348:Hellemans & Bunch 2004 2545:Coordinated Universal Time 2032: 1971:properties of crystalline 1846:, who first used the term 1666:Metropolitan Museum of Art 1642:Giovanni Battista Riccioli 933:Sophisticated timekeeping 349:Shadow clocks and sundials 162:in 1493–1494, and in 1582 8461: 8352: 8319: 8293: 8174: 8074: 8061:Time-translation symmetry 7991: 7965: 7948: 7872:International Atomic Time 7822: 7799: 7741:November 9, 2019, at the 7172:Moevs, Christian (1999). 7045:10.1103/PhysRevLett.1.105 6971:Asian and African Studies 6941:Macey, Samuel L. (1994). 6549:Glasmeier, Amy K (2000). 6534:. New York: Scala Books. 6410:van Dusen, David (2014). 6283:Colchester, L.S. (1987). 6247:. London: Little, Brown. 6029:Harcourt Trade Publishers 5962:University of Texas Press 4523:al-Hassan & Hill 1986 4334:. Science Museum (London) 3648:al-Hassan & Hill 1986 3101:. Yale. pp. 145–146. 2264:watch (1950s); astronaut 2157:Military use of the watch 2136:Nicolas Fatio de Duillier 1963:can be used to vibrate a 1352:Salisbury Cathedral clock 1242:Salisbury Cathedral clock 7459:Schafer, Edward (1963). 7247:de Solla Price, Derek J. 7107:Accurate Clock Pendulums 6982:Major, Fouad G. (1998). 6962:Magdolen, Dušan (2001). 4722:, pp. 100–101, 103. 4328:"Wells Cathedral clock, 3974:, pp. 223, 242–243. 2284:introduction of the tank 2192:officers. The so-called 2029:Development of the watch 1988:Shortt–Synchronome clock 1877:a new kind of escapement 1288:, the third part of the 1066:, by the Italian artist 662:and government official 634:The introduction of the 363:Rijksmuseum van Oudheden 289:astronomical observatory 8321:Astronomical chronology 8294:Archaeology and geology 8001:Absolute space and time 7917:IERS Reference Meridian 7912:International Date Line 7823:International standards 7506:Sidgwick, Benson John; 7024:Physical Review Letters 6498:; Olenick, Richard P.; 6289:. London: Unwin Hyman. 6173:Bradbury, Nancy Mason; 6104:Bedini, Silvio (1994). 6080:2027/mdp.39076006361401 5693:Sullivan, D.B. (2001). 3436:Dasypodius, K. (1580). 2694:Smithsonian Institution 2692:Science Museum and the 1316:Old St Paul's Cathedral 1128: 1122: 1116: 919:1221 by the astronomer 770:and included arrays of 377:in Jaipur Built in 1727 97:(or equally acceptable 37:. It is related to the 8552:History of timekeeping 8547:History of measurement 7539:Thomson, A.G. (1972). 7444:. Dover Publications. 6662:Hill, Donald Routledge 6268:. New York: Springer. 5789:Essen & Parry 1955 5707:on September 27, 2011. 3735:Flamer, Keith (2006). 2678: 2408: 1995:vacuum tube oscillator 1903: 1867: 1762: 1760:Science Museum, London 1669: 1626:Science Museum, London 1427: 1376: 1248: 1219: 1199:illuminated manuscript 1186: 1145: 1036: 835: 822:Chinese incense clocks 702: 598: 449: 378: 366: 323:Aboriginal Australians 264: 156:Leonardo da Vinci 42: 8537:History of technology 8280:Weekday determination 8166:Sundial markup schema 6239:Bruton, Eric (2000). 5801:Markowitz et al. 1958 5661:Deutsches Uhrenmuseum 4597:Frautschi et al. 2008 4585:Frautschi et al. 2008 4541:University of Houston 3902:, pp. 33–34, 37. 3614:, pp. 52, 55–56. 3569:. Stanford University 3451:Hero, of Alexandria. 3034:"Ptolemy on Sundials" 3032:Hart, Graham (1999). 2535:Clock synchronization 2507:Dimensional metrology 2485:energy levels of the 2388: 2171:Alberto Santos-Dumont 1897: 1862: 1746: 1651: 1425: 1379:The invention of the 1369: 1356:Wells Cathedral clock 1257:history of technology 1239: 1211:Villard de Honnecourt 1180: 1020: 845:characters, American 829: 812:Mustansiriya Madrasah 696: 646:inventors, Geng Xun ( 584: 474:) is credited by the 444: 396: BC (during the 372: 356: 313:modified their usual 255: 51:ancient civilizations 32: 8301:Chronological dating 8041:Theory of relativity 7902:Daylight saving time 7676:White, Lynn Townsend 7339:10.1017/pasa.2016.25 7127:The Mariner's Mirror 6944:Encyclopedia of Time 6734:Hüwel, Lutz (2018). 6496:Frautschi, Steven C. 6383:A Choice of Sundials 6262:Buick, Tony (2013). 6175:Collette, Carolyn P. 6134:. New York: Morrow. 5372:, pp. 172, 185. 4274:, pp. 353, 356. 4034:, pp. 180, 230. 2743:electrical resonance 2600:The inventor of the 1952:In 1857, the French 1815:Palais des Tuileries 1775:expansion properties 1690:differential gearing 1605:harmonic oscillators 1209:In 1250, the artist 1165:on duty to toll the 796:Ridwan ibn al-Sa'ati 756:Ibn Khalaf al-Muradi 636:water clock to China 357:An Ancient Egyptian 256:The Sun rising over 152:harmonic oscillators 8511:Time value of money 8306:Geologic time scale 8161:History of sundials 8026:Cosmological decade 7978:Greenwich Mean Time 7809:Orders of magnitude 7331:2016PASA...33...39N 7061:Marrison, Warren A. 7037:1958PhRvL...1..105M 6571:al-Hassan, Ahmad Y. 6504:Goodstein, David L. 6448:1955Natur.176..280E 6158:. Guildford Press. 6150:Blaut, James Morris 6061:(5). Philadelphia: 5908:10.1093/gr/43.2.157 5860:Alder, Ken (2002). 5803:, pp. 105–107. 5637:. December 31, 2015 5283:, pp. 124–125. 5235:, pp. 531–532. 4991:, pp. 147–148. 4855:, pp. 518–519. 4623:, pp. 515–516. 4455:Jacob Zech Original 4360:, pp. 126–128. 4317:, pp. 116–120. 3950:, pp. 120–121. 3938:, pp. 813–814. 3926:, pp. 145–146. 3725:, pp. 545–546. 3638:, pp. 104–106. 3555:, pp. 160–161. 3543:, pp. 103–104. 3374:, pp. 518–519. 3362:, pp. 345–347. 3287:A Walk Through Time 3269:, pp. 469–471. 3245:, pp. 479–480. 3188:on February 5, 2009 3072:, pp. 368–369. 2841:, pp. 158–159. 2817:, pp. 235–237. 2780:frequency stability 2268:in 1966, wearing a 2163:Franco-Prussian War 2140:natural philosopher 1924:extremely long life 1798:made from iron and 1716:deadbeat escapement 1157:as meaning 'bell'. 1094:, opportunity, and 1068:Ambrogio Lorenzetti 593:, 285–246 BC ( 402:Valley of the Kings 327:construct calendars 269:astronomical bodies 185:deadbeat escapement 101:) and later by the 83:were first used in 55:astronomical bodies 49:dates back to when 47:timekeeping devices 8486:Mental chronometry 8114:Marine chronometer 7966:Obsolete standards 7561:10.1007/BF03215167 7481:Schafer, Edward H. 7295:– via JSTOR. 7200:– via JSTOR. 6834:– via JSTOR. 6737:Of Clocks and Time 6698:. Hyperion Press. 6304:Cotterell, Brian; 6234:– via JSTOR. 6226:. 46/47: 130–148. 6183:The Chaucer Review 6126:Bergreen, Laurence 5918:– via JSTOR. 5841:Ajram, K. (1992). 5595:Clymer, Benjamin. 5349:Famous Watchmakers 4535:John H. Lienhard. 4088:, pp. 64, 79. 2747:crystal oscillator 2512:Forensic metrology 2436:magnetic resonance 2409: 2371:wearable computers 2344:mission. In 1969, 2266:Thomas P. Stafford 2035:History of watches 2003:crystal oscillator 1947:Charles Wheatstone 1904: 1868: 1836:Board of Longitude 1821:Marine chronometer 1763: 1670: 1658:Ferdinand Berthoud 1613:Christiaan Huygens 1587:Christiaan Huygens 1428: 1377: 1362:Later developments 1342:, built a complex 1249: 1220:horologia nocturna 1187: 1161:alarms warned the 1110:first appeared in 1079:Ferdinand Magellan 1037: 969:Muslim astronomers 836: 788:Jayrun Water Clock 742:Tower of the Winds 707:Greek philosophers 703: 699:Tower of the Winds 668:astronomical clock 621:Amenhotep III 599: 379: 367: 265: 176:Christiaan Huygens 134:Henry de Vick 43: 8524: 8523: 8334:Nuclear timescale 8016:Continuous signal 7752:History Repeating 7719:978-14815-6-390-1 7693:978-01950-0-266-9 7667:978-08122-2-357-6 7633:Thornton, Bonnell 7611:Robertus Anglicus 7598:978-05213-5-158-4 7498:978-0-900658-10-5 7472:978-0-520-05462-2 7451:978-0-486-42261-9 7398:978-01928-6-205-1 7375:978-04721-1-208-1 7221:978-05216-5-270-4 7164:978-18453-3-476-5 7117:978-01915-1-368-8 6995:978-0-387-98301-1 6954:978-0-8153-0615-3 6905:978-80730-8-668-8 6884:978-0-8153-0322-0 6775:978-90277-0-329-3 6756:al-Jazari, Ismail 6747:978-16817-4-096-6 6726:978-04150-6-136-0 6705:978-0-7868-8571-8 6679:978-0-415-15291-4 6653:978-08607-8-606-1 6629:978-06182-2-123-3 6588:978-0-521-42239-0 6562:978-15723-0-589-2 6541:978-09357-4-880-2 6519:978-11396-4-290-3 6487:978-0-691-02437-0 6423:978-90042-6-686-5 6371:978-0-521-81599-4 6347:978-01982-0-171-7 6336:Europe: A History 6321:978-05213-4-194-3 6296:978-00444-0-012-7 6275:978-14614-7-042-7 6254:978-05173-7-744-4 6195:10.1353/cr.0.0027 6165:978-1-57230-591-5 6141:978-0-06-621173-2 6117:978-0-521-37482-8 6047:Bedini, Silvio A. 6038:978-01560-0-649-1 6011:978-01995-8-951-7 5990:9-780-41327-3-901 5971:978-02927-0-502-9 5960:. Austin, Texas: 5941:978-01404-4-409-4 5896:Greece & Rome 5879:978-03168-5-989-9 5852:978-0-911119-43-5 5770:on April 12, 2008 5620:, pp. 33–38. 5247:, pp. 56–57. 5099:, pp. 65–66. 5003:, pp. 90–93. 4915:, pp. 86–87. 4867:, pp. 79–80. 4770:, pp. 24–25. 4671:, pp. 44–45. 4575:, pp. 67–68. 4428:, pp. 20–22. 4223:, pp. 64–65. 4124:, pp. 59–60. 4112:, pp. 87–88. 3998:, pp. 67–68. 3792:, pp. 83–92. 3737:"History of Time" 3531:, pp. 55–56. 3422:978-618-83695-0-4 3060:, pp. 37–38. 2995:, pp. 31–32. 2949:10.1558/jsa.34687 2763:vertical pendulum 2729:anchor escapement 2588:Explanatory notes 2527:Quantum metrology 1807:French Revolution 1771:gridiron pendulum 1756:gridiron pendulum 1413:Leonardo da Vinci 1203:Robertus Anglicus 1195:Bible of St Louis 1153:sources recorded 1106:The English word 939:Abū Rayhān Bīrūnī 850:Edward H. Schafer 786:The 12th-century 764:epicyclic gearing 656:steelyard balance 650:) and Yuwen Kai ( 511:ante merididiem). 287:equivalent of an 16:(Redirected from 8559: 8225:Dominical letter 8156:Equation of time 8119:Marine sandglass 7960: 7954: 7932:Terrestrial Time 7789:Time measurement 7782: 7775: 7768: 7759: 7758: 7723: 7711: 7697: 7685: 7671: 7650: 7628: 7602: 7581: 7563: 7545: 7535: 7502: 7490: 7476: 7455: 7431: 7402: 7390: 7379: 7358: 7324: 7296: 7243:Noble, Joseph V. 7238: 7225: 7201: 7168: 7156: 7142: 7121: 7100: 7056: 7014: 7012: 7010: 6978: 6968: 6958: 6937: 6919: 6909: 6888: 6869: 6849: 6840:Landes, David S. 6835: 6791: 6779: 6764:. Translated by 6751: 6730: 6709: 6697: 6683: 6671: 6657: 6633: 6620:Houghton Mifflin 6608: 6602: 6592: 6580: 6566: 6545: 6523: 6491: 6467: 6456:10.1038/176280a0 6427: 6406: 6386: 6375: 6351: 6339: 6325: 6300: 6279: 6258: 6246: 6235: 6214: 6169: 6145: 6121: 6100: 6082: 6042: 6026: 6015: 5994: 5975: 5959: 5945: 5933: 5919: 5883: 5867: 5856: 5826: 5825: 5823: 5821: 5810: 5804: 5798: 5792: 5786: 5780: 5779: 5777: 5775: 5760: 5747: 5741: 5735: 5734: 5732: 5730: 5715: 5709: 5708: 5706: 5699: 5690: 5684: 5678: 5672: 5671: 5669: 5667: 5653: 5647: 5646: 5644: 5642: 5627: 5621: 5615: 5609: 5608: 5606: 5604: 5592: 5586: 5585: 5583: 5581: 5569: 5563: 5557: 5551: 5545: 5539: 5538: 5536: 5534: 5520: 5514: 5508: 5502: 5496: 5490: 5484: 5478: 5472: 5466: 5460: 5454: 5453: 5451: 5449: 5434: 5421: 5415: 5409: 5403: 5397: 5391: 5385: 5379: 5373: 5367: 5361: 5360: 5358: 5356: 5341: 5335: 5329: 5323: 5317: 5311: 5305: 5299: 5293: 5284: 5278: 5272: 5266: 5260: 5254: 5248: 5242: 5236: 5230: 5224: 5218: 5212: 5206: 5200: 5194: 5188: 5182: 5173: 5167: 5161: 5155: 5149: 5143: 5137: 5136: 5134: 5132: 5118: 5112: 5106: 5100: 5094: 5088: 5082: 5076: 5070: 5064: 5058: 5052: 5046: 5040: 5034: 5028: 5022: 5016: 5010: 5004: 4998: 4992: 4986: 4980: 4979: 4977: 4975: 4961: 4955: 4949: 4940: 4934: 4928: 4922: 4916: 4910: 4904: 4898: 4892: 4886: 4880: 4874: 4868: 4862: 4856: 4850: 4844: 4843: 4841: 4839: 4825: 4819: 4813: 4807: 4801: 4795: 4789: 4783: 4777: 4771: 4765: 4759: 4753: 4747: 4741: 4735: 4729: 4723: 4717: 4711: 4705: 4699: 4693: 4684: 4678: 4672: 4666: 4660: 4654: 4648: 4642: 4636: 4630: 4624: 4618: 4612: 4606: 4600: 4594: 4588: 4582: 4576: 4570: 4564: 4558: 4552: 4551: 4549: 4547: 4532: 4526: 4520: 4514: 4508: 4502: 4501: 4473: 4467: 4466: 4464: 4462: 4447: 4441: 4435: 4429: 4423: 4417: 4411: 4405: 4399: 4388: 4382: 4373: 4367: 4361: 4355: 4344: 4343: 4341: 4339: 4331: 4324: 4318: 4312: 4306: 4305: 4303: 4301: 4296:on June 15, 2009 4292:. Archived from 4286: 4275: 4269: 4263: 4257: 4251: 4245: 4239: 4233: 4224: 4218: 4212: 4206: 4200: 4194: 4188: 4182: 4176: 4170: 4164: 4158: 4152: 4146: 4137: 4131: 4125: 4119: 4113: 4107: 4101: 4095: 4089: 4083: 4077: 4071: 4062: 4056: 4047: 4041: 4035: 4029: 4023: 4017: 4011: 4005: 3999: 3993: 3987: 3981: 3975: 3969: 3963: 3957: 3951: 3945: 3939: 3933: 3927: 3921: 3915: 3909: 3903: 3897: 3891: 3890: 3888: 3886: 3871: 3865: 3859: 3853: 3847: 3841: 3835: 3829: 3823: 3817: 3811: 3805: 3799: 3793: 3787: 3781: 3775: 3769: 3763: 3757: 3756: 3754: 3752: 3747:on July 16, 2011 3743:. Archived from 3732: 3726: 3720: 3714: 3708: 3702: 3701: 3699: 3697: 3683: 3677: 3676: 3674: 3672: 3657: 3651: 3645: 3639: 3633: 3627: 3621: 3615: 3609: 3603: 3597: 3591: 3585: 3579: 3578: 3576: 3574: 3562: 3556: 3550: 3544: 3538: 3532: 3526: 3517: 3511: 3505: 3499: 3493: 3487: 3481: 3475: 3469: 3463: 3457: 3456: 3448: 3442: 3441: 3438:Heron mechanicus 3433: 3427: 3426: 3408: 3402: 3396: 3387: 3381: 3375: 3369: 3363: 3357: 3351: 3345: 3339: 3333: 3327: 3321: 3315: 3309: 3303: 3302: 3300: 3298: 3279: 3270: 3264: 3258: 3252: 3246: 3240: 3234: 3228: 3222: 3216: 3210: 3204: 3198: 3197: 3195: 3193: 3187: 3180: 3171: 3165: 3164: 3157: 3151: 3145: 3139: 3136:& Dolan 1975 3133: 3127: 3124:& Dolan 1975 3121: 3115: 3109: 3103: 3102: 3094: 3085: 3079: 3073: 3067: 3061: 3055: 3049: 3048: 3046: 3044: 3038:Starry Messenger 3029: 3023: 3017: 3011: 3005: 2996: 2990: 2984: 2978: 2972: 2966: 2960: 2959: 2957: 2955: 2928: 2922: 2921: 2919: 2917: 2912:. March 14, 2013 2902: 2896: 2890: 2884: 2878: 2869: 2863: 2854: 2848: 2842: 2836: 2830: 2824: 2818: 2812: 2806: 2800: 2783: 2772: 2766: 2738: 2732: 2725: 2719: 2707:verge and foliot 2703: 2697: 2689: 2683: 2670: 2664: 2631: 2628: 2619: 2613: 2598: 2561:Seconds pendulum 2450:caesium standard 2275: 2262:Rolex Submariner 2250: 2241: 2230: 2221: 2117:mechanical watch 2103: 2058: 2047: 1961:electric current 1787:room temperature 1736:, clockmaker of 1720:Richard Towneley 1684:, fitted with a 1674:equation of time 1663: 1621:anchor mechanism 1571: 1562: 1553: 1486: 1457: 1430:Clock towers in 1418: 1410: 1394: 1332: 1304: 1254: 1246:verge and foliot 1240:A detail of the 1222: 1184: 1148: 1131: 1125: 1119: 1034: 1004:Alfred the Great 948: 918: 893: 884: 626: 615: 612: 546:. A north–south 534: 531: 527: 524: 473: 470: 418: 415: 410:winter solstices 395: 392: 198:. Following the 142: 139: 130:verge and foliot 92: 89: 35:marine sandglass 21: 8567: 8566: 8562: 8561: 8560: 8558: 8557: 8556: 8527: 8526: 8525: 8520: 8457: 8348: 8315: 8289: 8170: 8070: 8021:Coordinate time 7993:Time in physics 7987: 7961: 7955: 7946: 7818: 7795: 7786: 7743:Wayback Machine 7732: 7727: 7726: 7720: 7694: 7668: 7607:Thorndike, Lynn 7599: 7543: 7524: 7499: 7473: 7452: 7436:Rossotti, Hazel 7399: 7376: 7222: 7206:Needham, Joseph 7165: 7118: 7008: 7006: 6996: 6966: 6955: 6917: 6906: 6885: 6858: 6776: 6766:Hill, Donald R. 6748: 6727: 6706: 6680: 6654: 6638:Hill, Donald R. 6630: 6600: 6589: 6563: 6542: 6528:Frugoni, Chiara 6520: 6500:Apostol, Tom M. 6488: 6424: 6395: 6372: 6348: 6322: 6306:Kamminga, Johan 6297: 6286:Wells Cathedral 6276: 6255: 6166: 6142: 6118: 6071:10.2307/1005923 6039: 6012: 5991: 5972: 5942: 5888:Allen, Danielle 5880: 5853: 5835: 5830: 5829: 5819: 5817: 5812: 5811: 5807: 5799: 5795: 5787: 5783: 5773: 5771: 5762: 5761: 5750: 5742: 5738: 5728: 5726: 5717: 5716: 5712: 5704: 5697: 5691: 5687: 5679: 5675: 5665: 5663: 5655: 5654: 5650: 5640: 5638: 5629: 5628: 5624: 5616: 5612: 5602: 5600: 5593: 5589: 5579: 5577: 5570: 5566: 5558: 5554: 5546: 5542: 5532: 5530: 5524:"Non-magnetism" 5522: 5521: 5517: 5509: 5505: 5497: 5493: 5485: 5481: 5473: 5469: 5461: 5457: 5447: 5445: 5435: 5424: 5416: 5412: 5404: 5400: 5392: 5388: 5380: 5376: 5368: 5364: 5354: 5352: 5343: 5342: 5338: 5330: 5326: 5318: 5314: 5306: 5302: 5294: 5287: 5279: 5275: 5267: 5263: 5255: 5251: 5243: 5239: 5231: 5227: 5219: 5215: 5207: 5203: 5195: 5191: 5183: 5176: 5168: 5164: 5156: 5152: 5144: 5140: 5130: 5128: 5120: 5119: 5115: 5107: 5103: 5095: 5091: 5083: 5079: 5071: 5067: 5059: 5055: 5047: 5043: 5035: 5031: 5023: 5019: 5011: 5007: 4999: 4995: 4987: 4983: 4973: 4971: 4963: 4962: 4958: 4950: 4943: 4935: 4931: 4923: 4919: 4911: 4907: 4899: 4895: 4887: 4883: 4879:, pp. 7–8. 4875: 4871: 4863: 4859: 4851: 4847: 4837: 4835: 4829:"Julien Le Roy" 4827: 4826: 4822: 4814: 4810: 4802: 4798: 4790: 4786: 4778: 4774: 4766: 4762: 4754: 4750: 4742: 4738: 4730: 4726: 4718: 4714: 4706: 4702: 4694: 4687: 4679: 4675: 4667: 4663: 4655: 4651: 4643: 4639: 4631: 4627: 4619: 4615: 4611:, section 2–17. 4607: 4603: 4595: 4591: 4583: 4579: 4571: 4567: 4559: 4555: 4545: 4543: 4533: 4529: 4521: 4517: 4509: 4505: 4474: 4470: 4460: 4458: 4449: 4448: 4444: 4436: 4432: 4424: 4420: 4412: 4408: 4400: 4391: 4383: 4376: 4368: 4364: 4356: 4347: 4337: 4335: 4326: 4325: 4321: 4315:Colchester 1987 4313: 4309: 4299: 4297: 4288: 4287: 4278: 4270: 4266: 4258: 4254: 4246: 4242: 4234: 4227: 4219: 4215: 4207: 4203: 4195: 4191: 4183: 4179: 4171: 4167: 4159: 4155: 4147: 4140: 4136:, pp. 5–6. 4132: 4128: 4120: 4116: 4108: 4104: 4096: 4092: 4084: 4080: 4072: 4065: 4057: 4050: 4042: 4038: 4030: 4026: 4018: 4014: 4006: 4002: 3994: 3990: 3982: 3978: 3970: 3966: 3958: 3954: 3946: 3942: 3934: 3930: 3922: 3918: 3910: 3906: 3898: 3894: 3884: 3882: 3873: 3872: 3868: 3860: 3856: 3848: 3844: 3836: 3832: 3824: 3820: 3812: 3808: 3800: 3796: 3788: 3784: 3776: 3772: 3764: 3760: 3750: 3748: 3733: 3729: 3721: 3717: 3709: 3705: 3695: 3693: 3685: 3684: 3680: 3670: 3668: 3658: 3654: 3646: 3642: 3634: 3630: 3622: 3618: 3610: 3606: 3598: 3594: 3586: 3582: 3572: 3570: 3563: 3559: 3551: 3547: 3539: 3535: 3527: 3520: 3512: 3508: 3500: 3496: 3488: 3484: 3476: 3472: 3464: 3460: 3449: 3445: 3434: 3430: 3423: 3409: 3405: 3397: 3390: 3382: 3378: 3370: 3366: 3358: 3354: 3346: 3342: 3334: 3330: 3322: 3318: 3310: 3306: 3296: 3294: 3281: 3280: 3273: 3265: 3261: 3253: 3249: 3241: 3237: 3229: 3225: 3219:von Lieven 2016 3217: 3213: 3207:von Lieven 2016 3205: 3201: 3191: 3189: 3185: 3178: 3172: 3168: 3159: 3158: 3154: 3146: 3142: 3134: 3130: 3122: 3118: 3110: 3106: 3095: 3088: 3080: 3076: 3068: 3064: 3056: 3052: 3042: 3040: 3030: 3026: 3018: 3014: 3006: 2999: 2991: 2987: 2979: 2975: 2967: 2963: 2953: 2951: 2929: 2925: 2915: 2913: 2904: 2903: 2899: 2891: 2887: 2879: 2872: 2864: 2857: 2849: 2845: 2837: 2833: 2825: 2821: 2813: 2809: 2801: 2797: 2792: 2787: 2786: 2773: 2769: 2739: 2735: 2726: 2722: 2704: 2700: 2690: 2686: 2671: 2667: 2663: 2660: 2658: 2656: 2654: 2652: 2650: 2648: 2646: 2644: 2642: 2640: 2638: 2636: 2629: 2620: 2616: 2606:Warren Marrison 2599: 2595: 2590: 2585: 2517:Smart Metrology 2503: 2460:in 1955 at the 2383: 2373:in the form of 2357:digital watches 2323:stainless steel 2296:automatic watch 2280: 2279: 2278: 2277: 2258:automatic watch 2253: 2252: 2251: 2243: 2242: 2233: 2232: 2231: 2223: 2222: 2211: 2159: 2151:Thomas Earnshaw 2090: 2089: 2088: 2087: 2061: 2060: 2059: 2050: 2049: 2048: 2037: 2031: 2015:Warren Marrison 1957:Jules Lissajous 1943:electromagnetic 1908:Francis Ronalds 1892: 1890:Electric clocks 1823: 1712:repeating clock 1601: 1600: 1599: 1598: 1579:left and center 1574: 1573: 1572: 1564: 1563: 1555: 1554: 1524:harmonic motion 1520: 1518:Pendulum clocks 1515: 1495:Galileo Galilei 1451: 1405:Philip the Good 1364: 1276:Dante Alighieri 1234: 1225:verge mechanism 1175: 1104: 1090:that of death, 981: 931: 930: 929: 928: 896: 895: 894: 886: 885: 874: 824: 808:hours of prayer 613: 579: 532: 525: 471: 457:late Babylonian 416: 393: 351: 339:South Australia 250: 181:repeating clock 164:Galileo Galilei 140: 90: 53:first observed 45:The history of 23: 22: 15: 12: 11: 5: 8565: 8555: 8554: 8549: 8544: 8539: 8522: 8521: 8519: 8518: 8513: 8508: 8506:Time metrology 8503: 8498: 8493: 8488: 8483: 8482: 8481: 8471: 8465: 8463: 8462:Related topics 8459: 8458: 8456: 8455: 8450: 8445: 8440: 8435: 8430: 8425: 8420: 8415: 8410: 8405: 8400: 8395: 8390: 8385: 8380: 8375: 8370: 8365: 8359: 8357: 8350: 8349: 8347: 8346: 8341: 8336: 8331: 8325: 8323: 8317: 8316: 8314: 8313: 8308: 8303: 8297: 8295: 8291: 8290: 8288: 8287: 8282: 8277: 8272: 8267: 8262: 8257: 8252: 8247: 8242: 8237: 8232: 8227: 8222: 8217: 8212: 8207: 8201: 8196: 8191: 8186: 8180: 8178: 8172: 8171: 8169: 8168: 8163: 8158: 8153: 8151:Dialing scales 8148: 8143: 8138: 8137: 8136: 8126: 8121: 8116: 8111: 8106: 8101: 8096: 8091: 8086: 8080: 8078: 8072: 8071: 8069: 8068: 8063: 8058: 8053: 8048: 8043: 8038: 8033: 8028: 8023: 8018: 8013: 8008: 8003: 7997: 7995: 7989: 7988: 7986: 7985: 7983:Prime meridian 7980: 7975: 7973:Ephemeris time 7969: 7967: 7963: 7962: 7949: 7947: 7945: 7944: 7942:180th meridian 7939: 7934: 7929: 7924: 7919: 7914: 7909: 7904: 7899: 7894: 7889: 7884: 7879: 7874: 7869: 7864: 7859: 7854: 7849: 7844: 7839: 7838: 7837: 7826: 7824: 7820: 7819: 7817: 7816: 7811: 7806: 7800: 7797: 7796: 7785: 7784: 7777: 7770: 7762: 7756: 7755: 7745: 7731: 7730:External links 7728: 7725: 7724: 7718: 7698: 7692: 7672: 7666: 7651: 7629: 7603: 7597: 7582: 7536: 7522: 7508:Muirden, James 7503: 7497: 7477: 7471: 7456: 7450: 7432: 7414:(2): 244–248. 7403: 7397: 7380: 7374: 7359: 7297: 7269:10.2307/503828 7263:(4): 345–355. 7239: 7226: 7220: 7202: 7169: 7163: 7147:Miller, Judith 7143: 7133:(3): 257–276. 7122: 7116: 7101: 7057: 7031:(3): 105–107. 7015: 6994: 6979: 6959: 6953: 6938: 6910: 6904: 6889: 6883: 6870: 6856: 6836: 6808:10.1086/353360 6802:(4): 531–555. 6784:King, David A. 6780: 6774: 6752: 6746: 6731: 6725: 6710: 6704: 6684: 6678: 6658: 6652: 6634: 6628: 6609: 6593: 6587: 6567: 6561: 6546: 6540: 6524: 6518: 6492: 6486: 6472:Fraser, Julius 6468: 6428: 6422: 6407: 6393: 6376: 6370: 6352: 6346: 6330:Davies, Norman 6326: 6320: 6301: 6295: 6280: 6274: 6259: 6253: 6236: 6215: 6170: 6164: 6146: 6140: 6122: 6116: 6101: 6043: 6037: 6016: 6010: 5995: 5989: 5976: 5970: 5950:Aveni, Anthony 5946: 5940: 5920: 5884: 5878: 5857: 5851: 5837: 5836: 5834: 5831: 5828: 5827: 5805: 5793: 5791:, p. 280. 5781: 5748: 5736: 5725:. June 2, 2005 5710: 5685: 5683:, p. 484. 5673: 5648: 5622: 5610: 5587: 5564: 5552: 5550:, p. 137. 5540: 5515: 5503: 5491: 5479: 5467: 5455: 5443:Bloomberg News 5422: 5420:, p. 141. 5410: 5408:, p. 183. 5398: 5386: 5384:, p. 141. 5382:Glasmeier 2000 5374: 5362: 5336: 5334:, p. 280. 5324: 5322:, p. 129. 5312: 5310:, p. 219. 5300: 5298:, p. 128. 5285: 5273: 5261: 5259:, p. 114. 5249: 5237: 5225: 5223:, p. 564. 5213: 5211:, p. 533. 5201: 5199:, p. 538. 5189: 5187:, p. 527. 5174: 5172:, p. 526. 5162: 5160:, p. 478. 5150: 5148:, p. 523. 5138: 5122:"Pierre Curie" 5113: 5111:, p. 524. 5101: 5089: 5087:, p. 583. 5077: 5075:, p. 522. 5065: 5063:, p. 224. 5053: 5051:, p. 112. 5041: 5029: 5017: 5015:, p. 111. 5005: 4993: 4981: 4956: 4941: 4929: 4917: 4905: 4903:, p. 150. 4893: 4881: 4869: 4857: 4845: 4820: 4818:, p. 435. 4808: 4806:, p. 126. 4796: 4794:, p. 220. 4784: 4782:, p. 125. 4772: 4760: 4758:, p. 159. 4748: 4746:, p. 100. 4736: 4734:, p. 103. 4724: 4712: 4700: 4685: 4673: 4661: 4649: 4647:, p. 518. 4637: 4625: 4613: 4601: 4599:, p. 309. 4589: 4587:, p. 297. 4577: 4565: 4553: 4527: 4515: 4513:, p. 259. 4503: 4490:10.1086/346920 4484:(2): 469–506. 4468: 4442: 4430: 4418: 4416:, p. 123. 4406: 4404:, p. 529. 4389: 4374: 4362: 4345: 4319: 4307: 4276: 4264: 4262:, p. 434. 4252: 4240: 4238:, p. 515. 4225: 4213: 4201: 4199:, p. 244. 4189: 4177: 4175:, p. 134. 4165: 4153: 4138: 4126: 4114: 4102: 4100:, p. 248. 4090: 4078: 4076:, p. 243. 4063: 4061:, p. 514. 4048: 4036: 4024: 4012: 4010:, p. 120. 4000: 3988: 3976: 3964: 3962:, p. 122. 3952: 3940: 3928: 3916: 3904: 3892: 3866: 3864:, p. 209. 3854: 3852:, p. 570. 3842: 3830: 3828:, p. 186. 3818: 3806: 3794: 3790:al-Jazari 1974 3782: 3780:, p. 238. 3770: 3768:, p. 108. 3758: 3727: 3715: 3703: 3678: 3652: 3640: 3628: 3616: 3604: 3602:, p. 157. 3592: 3580: 3557: 3545: 3533: 3518: 3516:, p. 209. 3506: 3494: 3492:, p. 241. 3490:al-Jazari 1974 3482: 3480:, p. 203. 3470: 3468:, p. 234. 3458: 3443: 3428: 3421: 3403: 3401:, p. 242. 3388: 3376: 3364: 3352: 3340: 3338:, p. 157. 3328: 3326:, p. 257. 3324:van Dusen 2014 3316: 3314:, p. 411. 3304: 3283:"Early Clocks" 3271: 3259: 3257:, p. 128. 3247: 3235: 3223: 3221:, p. 218. 3211: 3209:, p. 207. 3199: 3174:Barry Perlus. 3166: 3152: 3140: 3128: 3116: 3104: 3086: 3074: 3062: 3050: 3024: 3012: 3010:, p. 130. 2997: 2985: 2973: 2961: 2943:(2): 217–223. 2923: 2897: 2885: 2883:, p. 510. 2870: 2855: 2843: 2831: 2829:, p. 130. 2819: 2807: 2794: 2793: 2791: 2788: 2785: 2784: 2767: 2759:torsion spring 2755:balance spring 2733: 2720: 2698: 2684: 2665: 2633: 2614: 2592: 2591: 2589: 2586: 2584: 2583: 2578: 2573: 2568: 2566:Time metrology 2563: 2558: 2553: 2548: 2542: 2537: 2531: 2530: 2529: 2524: 2522:Time metrology 2519: 2514: 2509: 2502: 2499: 2467:ephemeris time 2427:in the 1960s. 2382: 2379: 2369:, essentially 2319:Patek Philippe 2255: 2254: 2245: 2244: 2236: 2235: 2234: 2225: 2224: 2216: 2215: 2214: 2213: 2212: 2210: 2209:Modern watches 2207: 2198:trench warfare 2158: 2155: 2123:Thomas Tompion 2109:balance spring 2085:Thomas Tompion 2081:balance spring 2071:attached to a 2069:balance spring 2063: 2062: 2053: 2052: 2051: 2042: 2041: 2040: 2039: 2038: 2033:Main article: 2030: 2027: 2007:Walter G. Cady 1999:William Eccles 1959:showed how an 1935:Alexander Bain 1912:electric clock 1900:Alexander Bain 1891: 1888: 1863:Harrison's H4 1844:Jeremy Thacker 1822: 1819: 1654:equation clock 1609:pendulum clock 1585:, invented by 1583:pendulum clock 1576: 1575: 1566: 1565: 1557: 1556: 1548: 1547: 1546: 1545: 1544: 1519: 1516: 1514: 1511: 1499:Pisa Cathedral 1432:Western Europe 1395:1535) and the 1363: 1360: 1320:Jean Froissart 1244:, showing the 1233: 1230: 1174: 1171: 1112:Middle English 1103: 1100: 1021:A detail from 980: 977: 898: 897: 888: 887: 879: 878: 877: 876: 875: 873: 870: 861:incense sticks 839:Incense clocks 823: 820: 792:Umayyad Mosque 750:Ancient Romans 578: 575: 350: 347: 249: 246: 172:pendulum clock 115:Incense clocks 9: 6: 4: 3: 2: 8564: 8553: 8550: 8548: 8545: 8543: 8540: 8538: 8535: 8534: 8532: 8517: 8514: 8512: 8509: 8507: 8504: 8502: 8499: 8497: 8494: 8492: 8489: 8487: 8484: 8480: 8477: 8476: 8475: 8472: 8470: 8467: 8466: 8464: 8460: 8454: 8451: 8449: 8446: 8444: 8441: 8439: 8436: 8434: 8431: 8429: 8426: 8424: 8421: 8419: 8416: 8414: 8411: 8409: 8406: 8404: 8401: 8399: 8396: 8394: 8391: 8389: 8386: 8384: 8381: 8379: 8376: 8374: 8371: 8369: 8366: 8364: 8361: 8360: 8358: 8356: 8355:units of time 8351: 8345: 8344:Sidereal time 8342: 8340: 8337: 8335: 8332: 8330: 8329:Galactic year 8327: 8326: 8324: 8322: 8318: 8312: 8309: 8307: 8304: 8302: 8299: 8298: 8296: 8292: 8286: 8285:Weekday names 8283: 8281: 8278: 8276: 8275:Tropical year 8273: 8271: 8268: 8266: 8263: 8261: 8258: 8256: 8253: 8251: 8248: 8246: 8243: 8241: 8240:Intercalation 8238: 8236: 8233: 8231: 8228: 8226: 8223: 8221: 8218: 8216: 8213: 8211: 8208: 8206:(lunar Hijri) 8205: 8202: 8200: 8197: 8195: 8192: 8190: 8187: 8185: 8182: 8181: 8179: 8177: 8173: 8167: 8164: 8162: 8159: 8157: 8154: 8152: 8149: 8147: 8144: 8142: 8139: 8135: 8132: 8131: 8130: 8127: 8125: 8122: 8120: 8117: 8115: 8112: 8110: 8107: 8105: 8102: 8100: 8097: 8095: 8092: 8090: 8087: 8085: 8082: 8081: 8079: 8077: 8073: 8067: 8064: 8062: 8059: 8057: 8054: 8052: 8049: 8047: 8046:Time dilation 8044: 8042: 8039: 8037: 8034: 8032: 8029: 8027: 8024: 8022: 8019: 8017: 8014: 8012: 8009: 8007: 8004: 8002: 7999: 7998: 7996: 7994: 7990: 7984: 7981: 7979: 7976: 7974: 7971: 7970: 7968: 7964: 7959: 7953: 7943: 7940: 7938: 7935: 7933: 7930: 7928: 7925: 7923: 7920: 7918: 7915: 7913: 7910: 7908: 7905: 7903: 7900: 7898: 7895: 7893: 7890: 7888: 7885: 7883: 7882:24-hour clock 7880: 7878: 7877:12-hour clock 7875: 7873: 7870: 7868: 7865: 7863: 7860: 7858: 7855: 7853: 7850: 7848: 7845: 7843: 7840: 7836: 7833: 7832: 7831: 7828: 7827: 7825: 7821: 7815: 7812: 7810: 7807: 7805: 7802: 7801: 7798: 7794: 7790: 7783: 7778: 7776: 7771: 7769: 7764: 7763: 7760: 7753: 7749: 7746: 7744: 7740: 7737: 7734: 7733: 7721: 7715: 7710: 7709: 7703: 7702:Woods, Thomas 7699: 7695: 7689: 7684: 7683: 7677: 7673: 7669: 7663: 7659: 7658: 7652: 7648: 7644: 7640: 7639: 7634: 7630: 7626: 7622: 7618: 7617: 7612: 7608: 7604: 7600: 7594: 7590: 7589: 7583: 7579: 7575: 7571: 7567: 7562: 7557: 7553: 7549: 7548:Gold Bulletin 7542: 7537: 7533: 7529: 7525: 7523:9780894900495 7519: 7515: 7514: 7509: 7504: 7500: 7494: 7489: 7488: 7482: 7478: 7474: 7468: 7464: 7463: 7457: 7453: 7447: 7443: 7442: 7437: 7433: 7429: 7425: 7421: 7417: 7413: 7409: 7404: 7400: 7394: 7389: 7388: 7381: 7377: 7371: 7367: 7366: 7360: 7356: 7352: 7348: 7344: 7340: 7336: 7332: 7328: 7323: 7318: 7314: 7310: 7306: 7302: 7298: 7294: 7290: 7286: 7282: 7278: 7274: 7270: 7266: 7262: 7258: 7257: 7252: 7248: 7244: 7240: 7237:(282): 33–38. 7236: 7232: 7227: 7223: 7217: 7213: 7212: 7207: 7203: 7199: 7195: 7191: 7187: 7183: 7179: 7178:Dante Studies 7175: 7170: 7166: 7160: 7155: 7154: 7148: 7144: 7140: 7136: 7132: 7128: 7123: 7119: 7113: 7109: 7108: 7102: 7098: 7094: 7090: 7086: 7082: 7078: 7074: 7070: 7066: 7062: 7058: 7054: 7050: 7046: 7042: 7038: 7034: 7030: 7026: 7025: 7020: 7019:Markowitz, W. 7016: 7005: 7001: 6997: 6991: 6987: 6986: 6980: 6976: 6972: 6965: 6960: 6956: 6950: 6946: 6945: 6939: 6935: 6931: 6927: 6923: 6916: 6911: 6907: 6901: 6897: 6896: 6890: 6886: 6880: 6876: 6871: 6867: 6863: 6859: 6857:9780674768024 6853: 6848: 6847: 6841: 6837: 6833: 6829: 6825: 6821: 6817: 6813: 6809: 6805: 6801: 6797: 6796: 6790: 6785: 6781: 6777: 6771: 6767: 6763: 6762: 6757: 6753: 6749: 6743: 6739: 6738: 6732: 6728: 6722: 6719:. Routledge. 6718: 6717: 6711: 6707: 6701: 6696: 6695: 6689: 6688:Hoffman, Paul 6685: 6681: 6675: 6672:. Routledge. 6670: 6669: 6663: 6659: 6655: 6649: 6645: 6644: 6639: 6635: 6631: 6625: 6621: 6617: 6616: 6610: 6606: 6599: 6594: 6590: 6584: 6579: 6578: 6572: 6568: 6564: 6558: 6554: 6553: 6547: 6543: 6537: 6533: 6529: 6525: 6521: 6515: 6511: 6510: 6505: 6501: 6497: 6493: 6489: 6483: 6479: 6478: 6473: 6469: 6465: 6461: 6457: 6453: 6449: 6445: 6442:(4476): 280. 6441: 6437: 6433: 6429: 6425: 6419: 6415: 6414: 6408: 6404: 6400: 6396: 6394:9780828902106 6390: 6385: 6384: 6377: 6373: 6367: 6363: 6362: 6357: 6356:Dick, Stephen 6353: 6349: 6343: 6338: 6337: 6331: 6327: 6323: 6317: 6313: 6312: 6307: 6302: 6298: 6292: 6288: 6287: 6281: 6277: 6271: 6267: 6266: 6260: 6256: 6250: 6245: 6244: 6237: 6233: 6229: 6225: 6221: 6216: 6212: 6208: 6204: 6200: 6196: 6192: 6188: 6184: 6180: 6176: 6171: 6167: 6161: 6157: 6156: 6151: 6147: 6143: 6137: 6133: 6132: 6127: 6123: 6119: 6113: 6109: 6108: 6102: 6098: 6094: 6090: 6086: 6081: 6076: 6072: 6068: 6064: 6060: 6056: 6052: 6048: 6044: 6040: 6034: 6030: 6025: 6024: 6017: 6013: 6007: 6003: 6002: 5996: 5992: 5986: 5982: 5977: 5973: 5967: 5963: 5958: 5957: 5951: 5947: 5943: 5937: 5932: 5931: 5925: 5921: 5917: 5913: 5909: 5905: 5901: 5897: 5893: 5889: 5885: 5881: 5875: 5871: 5870:Little, Brown 5866: 5865: 5858: 5854: 5848: 5844: 5839: 5838: 5815: 5809: 5802: 5797: 5790: 5785: 5769: 5765: 5759: 5757: 5755: 5753: 5746:, p. 74. 5745: 5740: 5724: 5720: 5714: 5703: 5696: 5689: 5682: 5677: 5662: 5658: 5652: 5636: 5632: 5626: 5619: 5614: 5598: 5591: 5575: 5568: 5562:, p. 13. 5561: 5556: 5549: 5544: 5529: 5525: 5519: 5513:, p. 51. 5512: 5507: 5501:, p. 39. 5500: 5495: 5489:, p. 30. 5488: 5483: 5477:, p. 26. 5476: 5471: 5464: 5459: 5444: 5440: 5433: 5431: 5429: 5427: 5419: 5414: 5407: 5402: 5395: 5390: 5383: 5378: 5371: 5366: 5350: 5346: 5340: 5333: 5328: 5321: 5316: 5309: 5304: 5297: 5292: 5290: 5282: 5277: 5271:, p. 39. 5270: 5265: 5258: 5253: 5246: 5241: 5234: 5233:Marrison 1948 5229: 5222: 5221:Marrison 1948 5217: 5210: 5209:Marrison 1948 5205: 5198: 5197:Marrison 1948 5193: 5186: 5185:Marrison 1948 5181: 5179: 5171: 5170:Marrison 1948 5166: 5159: 5154: 5147: 5146:Marrison 1948 5142: 5127: 5123: 5117: 5110: 5109:Marrison 1948 5105: 5098: 5093: 5086: 5085:Marrison 1948 5081: 5074: 5073:Marrison 1948 5069: 5062: 5057: 5050: 5045: 5039:, p. 94. 5038: 5033: 5027:, p. 93. 5026: 5021: 5014: 5009: 5002: 4997: 4990: 4985: 4970: 4966: 4960: 4954:, p. 90. 4953: 4948: 4946: 4939:, p. 87. 4938: 4933: 4927:, p. 89. 4926: 4921: 4914: 4909: 4902: 4897: 4891:, p. 82. 4890: 4885: 4878: 4873: 4866: 4861: 4854: 4853:Marrison 1948 4849: 4834: 4830: 4824: 4817: 4812: 4805: 4800: 4793: 4788: 4781: 4776: 4769: 4768:Richards 1999 4764: 4757: 4752: 4745: 4740: 4733: 4728: 4721: 4716: 4710:, p. 41. 4709: 4708:Headrick 2002 4704: 4698:, p. 70. 4697: 4692: 4690: 4683:, p. 90. 4682: 4677: 4670: 4669:Headrick 2002 4665: 4659:, p. 44. 4658: 4657:Headrick 2002 4653: 4646: 4645:Marrison 1948 4641: 4635:, p. 72. 4634: 4629: 4622: 4621:Marrison 1948 4617: 4610: 4605: 4598: 4593: 4586: 4581: 4574: 4569: 4563:, p. 20. 4562: 4557: 4542: 4538: 4531: 4525:, p. 59. 4524: 4519: 4512: 4507: 4499: 4495: 4491: 4487: 4483: 4479: 4472: 4456: 4452: 4446: 4440:, p. 15. 4439: 4434: 4427: 4422: 4415: 4410: 4403: 4402:Lankford 1997 4398: 4396: 4394: 4387:, p. 19. 4386: 4381: 4379: 4372:, p. 66. 4371: 4366: 4359: 4354: 4352: 4350: 4333: 4323: 4316: 4311: 4295: 4291: 4285: 4283: 4281: 4273: 4268: 4261: 4256: 4249: 4244: 4237: 4236:Marrison 1948 4232: 4230: 4222: 4217: 4211:, p. 35. 4210: 4205: 4198: 4193: 4186: 4181: 4174: 4169: 4163:, p. 75. 4162: 4157: 4151:, p. 53. 4150: 4145: 4143: 4135: 4130: 4123: 4118: 4111: 4106: 4099: 4094: 4087: 4082: 4075: 4070: 4068: 4060: 4059:Marrison 1948 4055: 4053: 4046:, p. 49. 4045: 4040: 4033: 4028: 4022:, p. 67. 4021: 4016: 4009: 4004: 3997: 3992: 3985: 3980: 3973: 3968: 3961: 3956: 3949: 3944: 3937: 3936:Marrison 1948 3932: 3925: 3920: 3914:, p. 67. 3913: 3908: 3901: 3896: 3880: 3876: 3870: 3863: 3858: 3851: 3846: 3840:, figure 995. 3839: 3834: 3827: 3822: 3816:, p. 53. 3815: 3814:Bergreen 2003 3810: 3804:, p. 83. 3803: 3798: 3791: 3786: 3779: 3774: 3767: 3762: 3746: 3742: 3738: 3731: 3724: 3719: 3713:, Appendix B. 3712: 3707: 3692: 3688: 3682: 3667: 3663: 3656: 3650:, p. 24. 3649: 3644: 3637: 3632: 3626:, p. 56. 3625: 3620: 3613: 3608: 3601: 3600:Rossotti 2002 3596: 3590:, p. 37. 3589: 3584: 3568: 3561: 3554: 3549: 3542: 3537: 3530: 3525: 3523: 3515: 3510: 3504:, p. 43. 3503: 3498: 3491: 3486: 3479: 3474: 3467: 3462: 3455:. Alexandria. 3454: 3447: 3439: 3432: 3424: 3418: 3414: 3407: 3400: 3395: 3393: 3386:, p. 17. 3385: 3380: 3373: 3372:Humphrey 1998 3368: 3361: 3356: 3350:, p. 65. 3349: 3344: 3337: 3332: 3325: 3320: 3313: 3308: 3292: 3288: 3284: 3278: 3276: 3268: 3263: 3256: 3251: 3244: 3239: 3233:, p. 59. 3232: 3227: 3220: 3215: 3208: 3203: 3184: 3177: 3170: 3162: 3156: 3150:, p. 84. 3149: 3148:Magdolen 2001 3144: 3138:, p. 60. 3137: 3132: 3126:, p. 43. 3125: 3120: 3114:, p. 21. 3113: 3108: 3100: 3093: 3091: 3084:, p. 35. 3083: 3078: 3071: 3070:Thornton 1767 3066: 3059: 3054: 3039: 3035: 3028: 3022:, p. 34. 3021: 3016: 3009: 3004: 3002: 2994: 2989: 2983:, p. 18. 2982: 2977: 2971:, p. 14. 2970: 2965: 2950: 2946: 2942: 2938: 2934: 2927: 2911: 2907: 2901: 2894: 2889: 2882: 2881:Marrison 1948 2877: 2875: 2868:, p. 64. 2867: 2862: 2860: 2853:, p. 27. 2852: 2847: 2840: 2835: 2828: 2827:Richards 1999 2823: 2816: 2811: 2805:, p. 11. 2804: 2799: 2795: 2781: 2777: 2771: 2764: 2760: 2756: 2752: 2748: 2744: 2737: 2730: 2724: 2716: 2712: 2708: 2705:The original 2702: 2695: 2688: 2681: 2676: 2669: 2662: 2624: 2618: 2611: 2607: 2603: 2597: 2593: 2582: 2579: 2577: 2574: 2572: 2571:Time standard 2569: 2567: 2564: 2562: 2559: 2557: 2556:Quartz crisis 2554: 2552: 2549: 2546: 2543: 2541: 2538: 2536: 2533: 2532: 2528: 2525: 2523: 2520: 2518: 2515: 2513: 2510: 2508: 2505: 2504: 2498: 2496: 2492: 2488: 2484: 2483:electron spin 2480: 2476: 2471: 2469: 2468: 2463: 2459: 2455: 2451: 2446: 2444: 2441: 2437: 2433: 2428: 2426: 2425:atomic clocks 2422: 2418: 2413: 2412:Atomic clocks 2406: 2402: 2399: 2395: 2391: 2387: 2381:Atomic clocks 2378: 2376: 2372: 2368: 2364: 2362: 2358: 2353: 2351: 2347: 2343: 2339: 2335: 2331: 2326: 2324: 2320: 2315: 2313: 2309: 2305: 2301: 2297: 2293: 2289: 2285: 2271: 2267: 2263: 2259: 2249: 2240: 2229: 2220: 2206: 2204: 2199: 2195: 2191: 2187: 2182: 2180: 2179:Louis Cartier 2176: 2172: 2168: 2164: 2154: 2152: 2148: 2143: 2141: 2137: 2133: 2129: 2124: 2120: 2118: 2114: 2110: 2105: 2099: 2098:pocketwatches 2095: 2086: 2082: 2078: 2074: 2073:balance wheel 2070: 2066: 2057: 2046: 2036: 2026: 2024: 2020: 2016: 2012: 2008: 2004: 2000: 1996: 1991: 1989: 1984: 1982: 1978: 1974: 1970: 1969:piezoelectric 1966: 1962: 1958: 1955: 1950: 1948: 1944: 1940: 1936: 1931: 1929: 1925: 1921: 1917: 1916:electrostatic 1913: 1909: 1901: 1896: 1887: 1885: 1880: 1878: 1873: 1872:John Harrison 1866: 1861: 1857: 1855: 1851: 1850: 1845: 1841: 1837: 1832: 1828: 1818: 1816: 1812: 1808: 1803: 1801: 1797: 1793: 1788: 1784: 1780: 1779:George Graham 1776: 1772: 1769:invented the 1768: 1767:John Harrison 1761: 1757: 1753: 1752:John Harrison 1749: 1745: 1741: 1739: 1735: 1734:Julien Le Roy 1731: 1727: 1723: 1721: 1717: 1713: 1709: 1705: 1704:Edward Barlow 1702: 1698: 1693: 1691: 1687: 1683: 1679: 1678:sidereal time 1675: 1667: 1659: 1655: 1650: 1646: 1643: 1638: 1633: 1631: 1627: 1622: 1617: 1614: 1610: 1606: 1596: 1592: 1588: 1584: 1580: 1570: 1561: 1552: 1543: 1541: 1537: 1533: 1529: 1525: 1510: 1508: 1504: 1500: 1496: 1493: 1488: 1485: 1480: 1476: 1472: 1467: 1465: 1464:Gemma Frisius 1461: 1455: 1450: 1446: 1442: 1441:Peter Henlein 1438: 1433: 1424: 1420: 1414: 1406: 1402: 1398: 1390: 1386: 1382: 1375: 1374: 1368: 1359: 1357: 1353: 1347: 1346:in Florence. 1345: 1341: 1338:, the son of 1337: 1328: 1327:Henry de Vick 1323: 1321: 1317: 1313: 1309: 1300: 1295: 1293: 1292: 1291:Divine Comedy 1287: 1286: 1281: 1277: 1273: 1268: 1266: 1262: 1258: 1247: 1243: 1238: 1229: 1226: 1221: 1216: 1212: 1207: 1204: 1200: 1196: 1192: 1179: 1170: 1168: 1164: 1158: 1156: 1152: 1147: 1143: 1139: 1135: 1130: 1124: 1118: 1113: 1109: 1099: 1097: 1093: 1087: 1085: 1080: 1076: 1071: 1070:, from 1338. 1069: 1065: 1064: 1059: 1055: 1050: 1048: 1047: 1042: 1030: 1029: 1024: 1019: 1015: 1013: 1009: 1005: 1001: 996: 994: 990: 986: 976: 974: 973:observatories 970: 966: 964: 960: 956: 952: 944: 940: 936: 926: 922: 914: 910: 906: 902: 892: 883: 869: 865: 862: 857: 855: 851: 848: 844: 840: 833: 832:incense 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Retrieved 5116: 5104: 5097:Thomson 1972 5092: 5080: 5068: 5061:Ronalds 2015 5056: 5049:Barnett 1999 5044: 5032: 5020: 5013:Barnett 1999 5008: 4996: 4984: 4974:February 16, 4972:. Retrieved 4968: 4959: 4932: 4920: 4908: 4896: 4884: 4877:Matthys 2004 4872: 4860: 4848: 4836:. Retrieved 4833:Getty Center 4823: 4811: 4799: 4787: 4775: 4763: 4751: 4739: 4727: 4715: 4703: 4681:Barnett 1999 4676: 4664: 4652: 4640: 4628: 4616: 4604: 4592: 4580: 4568: 4556: 4544:. Retrieved 4530: 4518: 4511:Meskens 1992 4506: 4481: 4477: 4471: 4459:. Retrieved 4454: 4445: 4433: 4421: 4409: 4365: 4336:. Retrieved 4322: 4310: 4298:. Retrieved 4294:the original 4267: 4255: 4250:, p. 7. 4243: 4221:Barnett 1999 4216: 4204: 4192: 4187:, p. 5. 4180: 4168: 4161:Barnett 1999 4156: 4129: 4117: 4110:Barnett 1999 4105: 4093: 4086:Barnett 1999 4081: 4039: 4027: 4020:Barnett 1999 4015: 4003: 3991: 3986:, p. 4. 3979: 3967: 3955: 3943: 3931: 3919: 3907: 3900:Barnett 1999 3895: 3883:. Retrieved 3878: 3869: 3857: 3850:Needham 1965 3845: 3838:Needham 1965 3833: 3821: 3809: 3802:Frugoni 1988 3797: 3785: 3773: 3761: 3749:. Retrieved 3745:the original 3740: 3730: 3718: 3706: 3694:. Retrieved 3681: 3669:. Retrieved 3665: 3655: 3643: 3631: 3619: 3607: 3595: 3583: 3571:. Retrieved 3560: 3553:Schafer 1963 3548: 3536: 3509: 3497: 3485: 3473: 3461: 3452: 3446: 3437: 3431: 3412: 3406: 3379: 3367: 3355: 3343: 3331: 3319: 3312:Needham 1965 3307: 3295:. Retrieved 3286: 3267:Needham 1965 3262: 3255:Schafer 1967 3250: 3243:Needham 1965 3238: 3226: 3214: 3202: 3192:November 11, 3190:. Retrieved 3183:the original 3169: 3155: 3143: 3131: 3119: 3112:Barnett 1999 3107: 3098: 3077: 3065: 3053: 3041:. Retrieved 3037: 3027: 3015: 2988: 2981:Barnett 1999 2976: 2964: 2954:November 28, 2952:. Retrieved 2940: 2936: 2926: 2914:. 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New York. 5641:January 28, 5618:Nelson 1993 5560:Miller 2009 5548:Miller 2009 5511:Miller 2009 5499:Miller 2009 5487:Miller 2009 5475:Miller 2009 5463:Miller 2009 5406:Bruton 2000 5370:Landes 1985 5320:Landes 1985 5308:Landes 1985 5296:Landes 1985 5281:Landes 1985 5257:Landes 1985 5245:Bruton 2000 5131:January 28, 5037:Bruton 2000 5025:Bruton 2000 5001:Bruton 2000 4989:Landes 1985 4952:Bruton 2000 4937:Bruton 2000 4925:Bruton 2000 4913:Bruton 2000 4838:January 28, 4816:Davies 1996 4792:Landes 1985 4696:Bruton 2000 4633:Bruton 2000 4414:Thoren 1990 4260:Davies 1996 4209:Bruton 2000 4197:Bruton 2000 4149:Landes 1985 4098:Bruton 2000 4044:Bruton 2000 3996:Landes 1985 3924:Truitt 2015 3912:Landes 1985 3696:January 28, 3636:Bedini 1994 3624:Fraser 1990 3612:Fraser 1990 3588:Bedini 1963 3541:Bedini 1994 3529:Fraser 1990 3514:Pagani 2001 3297:October 13, 2969:Bruton 2000 2851:Norris 2016 2815:Bruton 2000 2803:Bruton 2000 2751:tuning fork 2621:A verse by 2458:Louis Essen 2454:caesium-133 2432:Lord Kelvin 2398:caesium-133 2390:Louis Essen 2361:transistors 2359:made using 2332:as part of 2294:style. The 2270:Speedmaster 2260:(1920s); a 2186:World War I 2173:, an early 2147:John Arnold 1965:tuning fork 1865:chronometer 1849:chronometer 1842:clockmaker 1701:mechanician 1528:equilibrium 1475:Taqi ad-Din 1452: [ 1437:Tycho Brahe 1096:Father Time 905:al-Bīrūnī's 768:gear trains 726:alarm clock 688:chain drive 676:Zhang Sixun 674:astronomer 644:Sui dynasty 629:Mesopotamia 614: 1500 603:water clock 591:water clock 533: 1500 526: 1400 453:clay tablet 394: 1200 231:smartphones 227:transistors 208:chronometer 141: 1360 103:Babylonians 91: 1200 67:oscillatory 8531:Categories 8516:Timekeeper 8469:Chronology 8453:Millennium 8339:Precession 8245:Julian day 8066:T-symmetry 7927:Solar time 7897:Civil time 7750:clip from 7647:1125642326 7322:1607.02215 7301:Norris, R. 6618:. Boston: 5868:. London: 5833:References 5666:August 17, 5603:August 15, 5599:. Hodinkee 5580:August 15, 5576:. Hodinkee 5533:August 15, 4901:Alder 2002 4889:Baker 2011 4865:Baker 2011 4804:Macey 1994 4780:Macey 1994 4756:Buick 2013 4744:Woods 2005 4732:Woods 2005 4720:Woods 2005 4609:Hüwel 2018 4358:White 1964 4173:White 1964 4122:Moevs 1999 4008:White 1964 3960:White 1964 3948:White 1964 3862:Macey 1994 3826:Blaut 2000 3766:Asser 1983 3711:Ajram 1992 3336:Allen 1996 3082:Dolan 1975 3058:Dolan 1975 3020:Dolan 1975 2993:Dolan 1975 2893:Major 1998 2839:Aveni 1980 2761:; and the 2630: 254 2610:solar time 2581:Watchmaker 2540:Clockmaker 2419:(NBS, now 2312:wristwatch 2203:Plexiglass 2138:, a Swiss 2134:together. 1825:After the 1754:—with his 1738:Versailles 1449:Jacob Zech 1389:stackfreed 1385:flintlocks 1381:mainspring 1272:Florentine 1215:escapement 1092:temperance 1077:navigator 1075:Portuguese 1023:Lorenzetti 1006:, king of 935:astrolabes 872:Astrolabes 847:sinologist 843:Devanagari 780:Archimedes 760:Al-Andalus 728:that used 714:Empedocles 710:Anaxagoras 540:plumb-line 461:Babylonian 434:, king of 428:2 Kings 20 417: 500 301:megalithic 281:Stonehenge 258:Stonehenge 219:wristwatch 145:mainspring 59:continuous 8413:Fortnight 8260:Lunisolar 8250:Leap year 8184:Gregorian 8134:stopwatch 8109:Hourglass 8089:Astrarium 8006:Spacetime 7937:Time zone 7814:Metrology 7793:standards 7625:897640056 7578:134442458 7570:0017-1557 7532:610565755 7428:198943520 7420:0003-5785 7355:119304459 7347:1323-3580 7293:193112893 7277:0002-9114 7190:0070-2862 7053:1079-7114 6934:1674-8042 6832:144315162 6816:0021-1753 6432:Essen, L. 6403:471181086 6211:154241097 6203:0009-2002 6089:0065-9746 5926:(1983) . 5729:August 1, 5681:Dick 2002 4546:April 10, 4498:143585356 4451:"History" 4074:Hill 1997 3972:Hill 1997 3778:Hill 1997 3723:King 1983 3502:Hill 2016 3478:Hill 1997 3466:Hill 1997 3399:Hill 1997 3384:Hill 2016 2790:Citations 2776:amplitude 2479:radiation 2407:in London 2342:Apollo 11 2330:spacewalk 2190:artillery 2113:frequency 2083:watch by 2079:an early 1983:in 1880. 1954:physicist 1920:dry piles 1840:Yorkshire 1748:Engraving 1540:amplitude 1536:dependent 1532:oscillate 1473:engineer 1460:longitude 1344:astrarium 1322:in 1369. 1261:regulator 1054:hourglass 1041:Al-Jazari 993:graduated 921:al‐Farisi 913:astrolabe 589:Egyptian 587:limestone 556:pole star 542:called a 455:from the 319:calendars 315:vigesimal 297:solstices 293:equinoxes 285:Stone Age 168:frequency 119:hourglass 71:pendulums 39:hourglass 8474:Duration 8448:Saeculum 8428:Olympiad 8270:Solstice 8199:Holocene 8176:Calendar 8076:Horology 7867:ISO 8601 7862:ISO 31-1 7739:Archived 7704:(2005). 7678:(1964). 7635:(1767). 7613:(1949). 7510:(1980). 7483:(1967). 7438:(2002). 7303:(2016). 7249:(1968). 7208:(1965). 7198:40166538 7149:(2009). 7097:88503681 7089:10999639 7063:(1948). 7009:June 22, 7004:37315254 6866:29148451 6842:(1985). 6786:(1983). 6758:(1974). 6690:(2004). 6664:(1997). 6530:(1988). 6506:(2008). 6474:(1990). 6358:(2002). 6332:(1996). 6308:(1990). 6232:41668444 6177:(2009). 6152:(2000). 6128:(2003). 6065:: 1–51. 6049:(1963). 5952:(1980). 5890:(1996). 5723:BBC News 4461:June 18, 4300:April 4, 3751:April 8, 3573:June 20, 2749:and the 2711:pendulum 2501:See also 2495:rubidium 2491:hydrogen 2338:Gemini 4 2292:Art Deco 2167:Boer War 2132:actuated 1928:humidity 1854:pamphlet 1656:made by 1595:Netscher 1507:Vincenzo 1503:pendulum 1492:polymath 1401:crossbow 1285:Paradiso 1265:horology 1191:friction 1167:monastic 1151:Germanic 987:is in a 949:1221. 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