People have measured time with shadows, dripping water, swinging pendulums and vibrating atoms, and they have argued about it the whole way. These stories visit a faceless medieval clock, a sundial on Mars, a year that lasted 445 days and a Swedish February 30. You will meet a carpenter who solved longitude, a woman who sold the time around London and an insect collector who wanted the clocks changed, plus two islands where yesterday and tomorrow sit 2.4 miles apart.
Every tile in a Clocks and Timekeeping game carries one of these. Open one to read it now, or leave them for the board to hand you.
Timepieces
nine stories
1A record-holding clock with no face
On the tile: Salisbury1386
Salisbury Cathedral's medieval clock has no face at all. It was built only to strike the hours, driven by falling weights that must be wound up once a day. The cathedral calls it the world's oldest working mechanical clock, dating it to 1386, but the record comes with a twist. Rival claims exist for clocks in Beauvais, France, and elsewhere, and at a 1993 symposium roughly a third of the experts present voted that this clock was much younger than the 1386 document it is linked to. It was restored to working order in 1956.
The story goes that after Master Hanuš built Prague's Old Town astronomical clock, the city councilmen had him blinded so he could never build a finer one elsewhere, and that he took revenge by stopping the clock. The legend was retold by the Czech writer Alois Jirásek. What is actually known is gentler: the clock was built in 1410 by Mikuláš of Kadaň, and Hanuš of Růže perfected its mechanism late in the 15th century. The clock really did stop in 1865, until the Prague watchmaker Ludvík Hainz repaired it.
Tall pendulum clocks in wooden cases were once simply tall case or eight-day clocks. Their cozier name came from a hit song. In 1876 Henry Clay Work, the American songwriter behind "Marching Through Georgia," published "Grandfather's Clock," in which a clock bought on the morning of the grandfather's birth is too big for the shelf and stands on the floor for ninety years. The song was enormously popular, and by some loathed. Furniture dealers borrowed its title, the shorter "grandfather clock" was in use by 1894, and it is now the usual name for the whole style.
According to a tradition first written down in the late 1800s, an officer of Marie Antoinette's guard asked Abraham-Louis Breguet around 1783 for a watch with every complication then known, with no limit on time or cost. The queen was executed in 1793 and never saw it. Breguet himself died four years before watch No. 160 was finished, in 1827, under his son Antoine-Louis. In 1983 it was stolen from the L.A. Mayer Museum in Jerusalem. It resurfaced in 2007, 24 years after the theft.
While reviewing instruments for a planned Mars lander, Bill Nye, the Science Guy, noticed that a camera's color-calibration target looked like a sundial. Colleagues were skeptical at first, he recalled, but the idea stuck. In 2004 the rovers Spirit and Opportunity carried what Cornell University called the first interplanetary sundials, each about 3 inches square. They bear the motto "Two Worlds, One Sun" and the name Mars in 17 languages. Because Nye and astronomer Woody Sullivan are baseball fans, weight-saving holes underneath are shaped like home plate.
Inside a mountain in West Texas, the Long Now Foundation has been assembling a clock designed to keep time for the next 10,000 years. Its shaft is 500 feet tall and 12 feet wide. Sunlight entering the top heats a chamber of air, and that motion helps wind the clock; visitors can also wind it by turning a huge capstan. Its chime generator, designed with help from musician Brian Eno, can ring more than 3.5 million different sequences, one for every day the clock is visited. The foundation even writes years with five digits, as in 02018.
In the law courts of ancient Athens, speeches ran on water. A klepsydra, a name built from Greek words for thief and water, was a vessel that drained through a small opening, and it measured how long the prosecutor and the defendant were each allowed to speak. When the water ran out, so did the speaker's time. A fragmentary klepsydra from the late fifth century BC is marked to hold two choes, about 6.4 liters of water, which took about six minutes to drain away.
In 2013 a University of Basel team clearing the entrance to a tomb in Egypt's Valley of the Kings found a flattened piece of limestone with a black semicircle drawn on it. The half circle is divided into twelve sections of about 15 degrees, and a dent in the middle held a wooden or metal peg to cast a shadow. It lay among stone huts that housed the men building the royal tombs in the 13th century BC, and it may have measured their working hours. The team called it one of the oldest Egyptian sundials ever found.
Watches in advertisements usually show about ten past ten, and a persistent rumor says the pose honors the moment Abraham Lincoln or John F. Kennedy was shot. Neither fits. Lincoln was shot at about 10:13 p.m. and died at about 7:22 the next morning, and Kennedy was shot at 12:30 p.m. The real reason is design: the hands frame a maker's logo below the 12 instead of drooping into a frown. The rumor is old. A book from 1934 was already dismissing a version about jewelers' dummy clocks set to 8:18.
By Julius Caesar's time, Rome's calendar had drifted badly out of step with the seasons. Its ordinary year was only 355 days, and extra days had to be inserted now and then to keep it on track. Advised by the Alexandrian astronomer Sosigenes, Caesar fixed it by brute force. In 46 BC he inserted 90 extra days, including two brand-new months totaling 67 days between November and December. That 445-day stretch became known as the last year of confusion, and his new solar calendar took over after it.
A popular story says Emperor Augustus wanted his month to be as long as July, so he took a day from February to give August 31 days. It is not true. The tale may have been invented by the 13th-century scholar Johannes de Sacrobosco. Julius Caesar's reform had already given the month, then called Sextilis, 31 days. Augustus did fix a real problem: priests had been adding leap days every three years instead of every four. Sextilis was renamed for him in 8 BC because it was the month in which he had first become consul, taken Egypt and ended the civil wars.
Our year numbers come from a sixth-century monk in Rome, Dionysius Exiguus, whose surname means the Little. While extending a table of Easter dates, he counted years from the birth of Christ instead of from the reign of Diocletian, a persecutor of Christians he did not want remembered. The idea spread slowly; Charlemagne is said to have been the first ruler to use it officially. There is no year zero, since 1 BC is followed by AD 1. And many historians now think Jesus was born between 6 and 4 BC.
By the 1500s the old Julian calendar had drifted about ten days, pushing the spring equinox away from March 21. So Pope Gregory XIII ordered that in 1582, October 4 would be followed directly by October 15. The Spanish mystic Teresa of Ávila died at Alba de Tormes on October 4, 1582, the very night the change took effect. The following day was reckoned as October 15. When she was canonized in 1622, her feast day was fixed on October 15.
Sweden decided to move to the Gregorian calendar gradually, by leaving out leap days one at a time. It skipped the leap day in 1700, but then, by error, kept the leap days of 1704 and 1708. That left the country one day ahead of the old Julian calendar and ten days behind the new one. King Charles XII ordered a return to the Julian calendar, so in 1712 February got an extra day, February 30, making a 367-day year. Sweden finally switched in 1753, when February 17 was followed by March 1.
When Britain changed calendars in 1752, September 2 was followed by September 14. A popular story says angry crowds rioted, demanding "Give us our eleven days." Historians have found little evidence of it. Most accounts rest on two sources: a satirical magazine and William Hogarth's painting An Election Entertainment. In the painting, a banner reading "Give us our Eleven Days" has been captured from a Tory crowd, but the scene lampoons a notoriously corrupt 1754 Oxfordshire election, not a calendar riot.
7Washington's two birthdays, and a holiday on neither
On the tile: Washington1732
George Washington was born in Virginia on February 11, 1731, by the Julian calendar then used in Britain's colonies. In 1752 Britain and its colonies adopted the Gregorian calendar, which dropped 11 days and moved New Year's Day from March 25 to January 1. That shifted his birthday to February 22, 1732. His birthday was long celebrated on February 22, but a 1968 law moved the federal holiday to the third Monday in February. That Monday can never fall later than February 21, so the holiday never lands on his actual birthday.
In October 1793, revolutionary France created a calendar that counted years from the founding of the Republic on September 22, 1792. Its 12 months each held three ten-day weeks called décades, and five or six extra days ended the year. The poet Fabre d'Églantine named the months for the seasons, such as Brumaire for fog and Thermidor for heat, and almost every day was named for a plant, animal, mineral or farm tool. The Republic even tried decimal time, with ten-hour days. Napoleon abolished the calendar, and the old one returned on January 1, 1806.
In 1929 the Soviet Union abolished the shared day off to keep factories running every day. Under the continuous week, workers were split into five groups, each marked by a color or symbol such as a wheat sheaf, a red star or a hammer and sickle, and each group rested on a different day. One calendar told readers to remember their color to know their rest day. People color-coded friends in address books by day off, and workers grumbled that they never saw their families. A six-day week followed in 1931, and the seven-day week returned in 1940.
John Harrison was a carpenter by trade who taught himself clockmaking. By the mid-1720s his precision longcase clocks kept time to within one second a month, far better than other clocks of the day. He then spent decades chasing the rewards Britain offered for finding longitude at sea, which required a clock that kept time aboard a rolling ship. His fourth timekeeper, H4, looked like a large pocket watch and ticked five times a second. On its 1761 trial voyage to Jamaica, his son William used it to predict landfall at Madeira earlier than the crew expected.
2The pendulum clock that shrank minutes to seconds
On the tile: Huygens1656
Christiaan Huygens needed precise time for his astronomy, and he was intrigued by Galileo's discovery that a pendulum's swings keep a steady beat. He completed a prototype of his first pendulum clock by the end of 1656, hired a local clockmaker named Salomon Coster to build more, and patented the design on June 16, 1657. The improvement was dramatic. His clocks drifted about fifteen seconds a day, while other timekeepers of the era could be off by fifteen minutes. Pendulum clocks went on to dominate precise timekeeping for centuries.
In 1088 Su Song, an astronomer of China's Song dynasty, built a water-driven astronomical clock tower more than 30 feet tall. At the top an armillary sphere tracked the sun and stars, in the middle a celestial globe showed the sky, and at the bottom sat the timekeeping works, regulated by a mechanism much like the escapement in later clocks. Su Song described its design in a book. The tower was destroyed after the upheaval known as the Jingkang Incident, and later generations could not master its mechanism. Reconstructions came only in recent decades.
The engineer al-Jazari, who died in 1206, described fifty mechanical devices in his Book of Knowledge of Ingenious Mechanical Devices. His elephant clock was especially intricate. Inside the elephant, a bowl with a hole in its bottom slowly sank in a hidden water tank. Every half hour, the bird on the dome whistled, a man dropped a ball into a dragon's mouth, and the driver struck the elephant with his goad. The design combined cultures: an Indian elephant, Chinese dragons, an Egyptian phoenix and figures in Arabian dress.
In 1753, at age 22, Benjamin Banneker, a free African American living on his family's farm outside Baltimore, built a striking clock almost entirely of wood. By one account he had seen only two timepieces, a sundial and a pocket watch. He took a pocket watch apart to study it, used his own observations and calculations to design the clock, and carved its pieces by hand. People traveled to see it. Banneker later helped survey the boundaries of Washington, D.C. The clock was lost when his house burned days after his death in 1806.
6The insect collector who wanted the clocks changed
On the tile: George Hudson1895
George Vernon Hudson worked shifts at the post office in Wellington, New Zealand, and spent his spare hours collecting insects, so he treasured daylight after work. On October 16, 1895, he presented a paper to the Wellington Philosophical Society proposing a two-hour seasonal shift of the clocks. Several members ridiculed it, and one dismissed it as unscientific and impracticable. Hudson made a longer case in 1898. New Zealand tried one hour of summer time in 1927, and his insect collection is considered perhaps the finest private one ever made in the country.
7The railway engineer who sliced the world into hours
On the tile: S. Fleming1884
Sandford Fleming, a Scottish-born engineer who became Canada's foremost railway surveyor, reportedly turned into a champion of time zones after an uncomfortable night stranded in a railway station because of time confusion. He argued for dividing the world into 24 zones, each 15 degrees of longitude and one hour wide, starting at Greenwich. At the 1884 International Prime Meridian Conference in Washington, he was the only delegate to distribute a position paper. Decades earlier, in 1851, he had designed Canada's first postage stamp, which helped make the beaver a Canadian emblem.
Until the end of the 1700s, clocks were made by hand one part at a time, so they were expensive and not widely owned. In 1807 the Connecticut clockmaker Eli Terry agreed to make 4,000 tall case clock movements for Edward and Levi Porter of Waterbury within three years, far beyond any clockmaker's capacity. He redesigned his factory and methods and delivered. The Porter Contract has been called the first successful large-scale production of a complicated mechanism with truly interchangeable parts. His cheaper wooden shelf clocks later became a staple of Yankee peddlers.
In 1955 Louis Essen and J. V. L. Parry at Britain's National Physical Laboratory built a clock that measured time by a change of state in cesium atoms. The Science Museum, which holds it, calls it the first successful atomic clock: accurate to a second in 300 years, about 30 times better than quartz clocks. In 1967 the second itself was redefined using cesium atoms instead of astronomy. Essen also measured the speed of light and challenged parts of Einstein's relativity, and his laboratory says he retired in 1972 after being quietly warned to stop.
In the 1800s, American railroads ran trains by their own clocks, so different companies could keep different times, a confusing and dangerous arrangement. The railroads adopted a plan by William F. Allen, editor of the Traveler's Official Railway Guide, with five zones: Intercolonial, Eastern, Central, Mountain and Pacific. On November 18, 1883, railroad clocks were reset as standard-time noon arrived in each zone, even clocks that had already passed noon. That is why it was called the Day of Two Noons. Standard time did not become federal law until 1918.
When clocks in Samoa struck midnight on Thursday, December 29, 2011, the country jumped straight to Saturday, December 31. By moving to the west side of the International Date Line, Samoa and neighboring Tokelau joined the same day as Australia and New Zealand, where many Samoans live. Workers scheduled for the vanished Friday got full pay. The jump reversed a switch made in 1892, when American traders persuaded Samoa to line up with the United States, and the islands celebrated the Fourth of July twice.
Benjamin Franklin is often credited with inventing daylight saving time. What he actually wrote, in the Journal de Paris in 1784, was satire. Posing as a man astonished to learn that the sun rises at six in the morning, he urged Parisians to get up earlier and save candles. He proposed taxing window shutters, rationing candles and ringing church bells at sunrise, and, if that failed, he wrote, "let cannon be fired in every street, to wake the sluggards effectually." He never suggested moving the clocks. That came more than a century later.
Since 1968, most of Arizona has stayed on Mountain Standard Time all year. The Navajo Nation, which also covers parts of Utah and New Mexico, observes daylight saving time, so from March to November it runs an hour ahead of the rest of Arizona. Inside the Navajo Nation lies the Hopi Reservation, which does not, and inside that sits a pocket of Navajo land that does. The result is a doughnut of clock changes. In Tuba City, where U.S. 160 marks the border between the reservations, a hotel on the Hopi side keeps a lobby clock for each time zone.
During the 1973 energy crisis, President Richard Nixon signed a law putting the United States on daylight saving time year-round for about two years, starting January 6, 1974. He cited expected winter savings equal to about 150,000 barrels of oil a day. Americans soon soured on dark winter mornings. Support fell from 79 percent in December 1973 to 42 percent by February 1974, and in October 1974 President Gerald Ford signed legislation ending the experiment early.
Atomic clocks tick more steadily than Earth turns, so since 1972 timekeepers have occasionally added a leap second to keep official time in step with the planet. The day's last minute then runs to 23:59:60. Twenty-seven were added through 2016. Because leap seconds can trip up satellite navigation, telecommunications and power grids, in 2022 the General Conference on Weights and Measures decided that by 2035 clocks may drift further from Earth's spin, enough to go at least a century without a jump. Meanwhile, a recent slight speedup in Earth's spin has raised the prospect of a first negative leap second.
Corals lay down a fine growth line each day and a thicker band each year. In the early 1960s, Cornell paleontologist John Wells counted the daily lines between annual bands on fossil corals from the Middle Devonian period and found about 400 per year. The year was about as long as ours, so the days had to be shorter. Earth's spin has been slowing as ocean tides raised by the Moon act as a brake. A 2020 study of a 70-million-year-old rudist clam counted 372 days a year, each about half an hour shorter than ours.
Long before it marked New Year's Eve, a falling ball told sailors the time. In 1833 the Royal Observatory at Greenwich put a time ball on its roof so ships on the Thames could check their clocks. It still rises halfway at 12:55 p.m., reaches the top at 12:58 and drops at exactly 1:00. In New York, a ball atop the Western Union Building dropped daily at noon on a telegraph signal from the Naval Observatory. It may have inspired New York Times publisher Adolph Ochs, who in 1907 replaced his New Year's fireworks with a lighted 700-pound ball lowered in Times Square.
For nearly half a century, Ruth Belville sold Londoners the time. Every Monday she traveled to the Royal Observatory at Greenwich, had tea with the porter and got a certificate that her pocket chronometer, nicknamed Arnold, was accurate. Then she made her rounds of 30 to 40 paying customers, including clock shops, who set their clocks by it. Her father started the service in 1836 and her mother kept it going. Ruth took over in 1892 and kept going despite competition from the Standard Time Company and the spread of telegraph wires, until she retired in 1940, at 85.