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The most accurate experimental pendulum clock ever made [22] [23] may be the Littlemore Clock built by Edward T. Hall in the 1990s [24] (donated in 2003 to the National Watch and Clock Museum, Columbia, Pennsylvania, USA). The largest pendulum clocks, exceeding 30 m (98 ft), were built in Geneva (1972) and Gdańsk (2016). [25] [26]
The most accurate pendulum clocks were controlled electrically. [166] The Shortt–Synchronome clock, an electrical driven pendulum clock designed in 1921, was the first clock to be a more accurate timekeeper than the Earth itself. [167] A succession of innovations and discoveries led to the invention of the modern quartz timer.
In 1657 Ahasuerus's son John Fromanteel began studying pendulum clocks, invented by Christiaan Huygens (1656). [1] Before the invention of the pendulum clock, timepieces were accurate to only within ten to fifteen minutes a day.
c. 3500 BC - Egyptian obelisks are among the earliest shadow clocks. [1] c. 1500 BC - The oldest of all known sundials, dating back to the 19th Dynasty. [2] c. 500 BC - A shadow clock is developed similar in shape to a bent T-square. [3] 3rd century BC - Berossos invents the hemispherical sundial. [4] 270 BCE - Ctesibius builds a water clock.
In a verge pendulum clock (see picture) which appeared after the pendulum was invented in 1656, the escapement was turned 90° so the verge rod was horizontal, while the escape wheel's axis was vertical, located under the verge rod. In the first pendulum clocks the pendulum was attached to the end of the verge rod instead of the balance wheel ...
Other clocks were exhibitions of craftsmanship and skill, incorporating astronomical indicators and musical movements. The cross-beat escapement was invented in 1584 by Jost Bürgi, who also developed the remontoire. Bürgi's clocks were a great improvement in accuracy as they were correct to within a minute a day.
Pendulum clocks were used as time standards until World War 2, although the French Time Service continued using them in their official time standard ensemble until 1954. [70] Pendulum gravimeters were superseded by "free fall" gravimeters in the 1950s, [71] but pendulum instruments continued to be used into the 1970s.
Cuckoo clock, a so-called Jagdstück ("hunt piece"), Black Forest, c. 1900, Deutsches Uhrenmuseum, Inv. 2006-013. A cuckoo clock is a type of clock, typically pendulum driven, that strikes the hours with a sound like a common cuckoo call and has an automated cuckoo bird that moves with each note.