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Saturday, 10 May 2014

Clock

The Egyptians invented the water-clock around 1500 BC. The device, called a clepsydra, consisted of a pot with a hole in the bottom. As it always took the same time to empty the vessel, people could easily tell the hour of day and night by merely watching the water's level in the bowl.

As the new clock spread all over the Mediterranean world, the design gradually improved. A floater was put on the water, now gathered in a vessel beneath, and linked to a gear which moved a pointer that turned in a circle. Behind this "hand" was placed a dial marked off all around and at regular intervals with the old sundial's figures from 1 to 12.

The hour glass was invented about the year 250 BC, replacing water with pure, dry sand. The quantity passing through a narrow neck between two bulbs determined the time.

It is not known for what purpose the hour glass was first devised. Some assert that the Roman army first introduced it to measure "watches" in the night.

A monk at Chartres, skilled in glass-blowing, is credited with having created the hour glass' final shape in the 8th century AD

During the Middle Ages, the hour glass was used to time tournaments and helped housewives in boiling their eggs. Congregations were said to restrict the time of their parson's sermon by placing a sand clock conspicuously on the pulpit.

The earliest known mechanical clock was built in China in 725.

The time on the earliest clocks could be heard and not seen, as instead of clock faces, they marked the passing of time with bells. Indeed the word "clock" comes from the Latin clocca (bell).

It was in Norwich, England, in 1273 that we read of the first mechanical clock in Europe.

The earliest mechanical clock was driven by falling weights attached to gear trains. Because it was regulated by friction, it was extremely inaccurate, by as much as two hours a day.

It is now believed that the earliest mechanized time-keepers were invented specifically to help people in saying their prayers.

The first known public clock appeared on the Viscount of Milan's palace in 1335.

Around the same time Richard of Wallingford mounted a huge device on the church at St Albans that could not only tell you what hour and minute it was, but also the state of tides at London Bridge.

During his student days Galileo Galilei's observation of a swinging lamp in Pisa Cathedral led him to discover the uniformity of the Pendulum. The Italian's work enabled his friend, the Dutch Scientist, Christiaan Huygens, to construct the first pendulum clock in 1656.

Christiaan Huygens' invention of the pendulum clock allowed everyone from traders to farmers and military commanders to know precisely what the time was.

Until 1670 clocks had short pendulums and were hung on the wall. Then William Clements invented the longer pendulum and the grandfather clock came into being.

There was only one pointer, the hour hand, on the first clocks made in the fourteenth century. The minute and seconds hands were added in the sixteenth and seventeenth centuries.

Sundial cannons were used by European royalty in the 18th century. The device incorporated a cannon with a fuse that was lit by an overhanging lens, concentrating the rays of the sun, and causing the cannon to fire at noon, signifying the time for their midday meal.

Simon Willard (1753-1848) established his clock factory in Roxbury, Massachusetts about 1778. He would turn out over 5,000 timepieces by the time he retired in 1839.

Willard patented the "Willard Patent Timepiece" (1802), still familiar as the banjo wall clock, and an alarm clock (1819).

The name grandfather clock was adopted after the song “Grandfather's Clock, ” written in 1876 by Henry Clay Work, became popular.

      Dresden Clock
                                                           
In 1929 a clock driven by a quartz crystal oscillator was developed as a scientific time-measuring device.

Daniel Biasone, founding owner of the National Basketball League's Syracuse Nationals, invented the 24-second shot clock in 1954.

London's Big Ben is the biggest four-faced, chiming clock in the world.

Putting Big Ben’s hands forwards or back in spring or autumn, plus a maintenance check, takes 16 hours. On the same weekend, 2,000 other clocks in the Palace of Westminster must be changed.

The Tower of Independence clock on the back of a U.S. $100 dollar bill shows the time as 4:10.

In almost all commercial and print advertisements, clocks and watches read 10:10

In Pulp Fiction all the clocks on the wall in the pawn shop are set to 4:20. The significance of the time 4:20 is that it is slang for smoking marijuana.

A clock's hands overlap 11 times in 12 hours, or 22 times in one day.


Modern clocks are actually more consistent than Earth's orbit around the Sun, which can vary by several milliseconds a year.

Clocks run clockwise because that's the way shadows move on sundials in the northern hemisphere.

Sources Europress Family Encyclopedia 1999, Compton's Interactive Encyclopedia © 1998 The Learning Company, Inc,  The Independent 

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