are a specific type of building which house a turret clock
and have one or more clock faces
on the upper exterior walls. Many clock towers are freestanding structures but they can also adjoin or be located on top of another building. Some other buildings also have clock faces on their exterior but these structures serve other main functions.
Clock towers are a common sight in many parts of the world with some being iconic buildings. One example is the Elizabeth Tower
in London (usually called "Big Ben
", although strictly this name belongs only to the bell inside the tower).
There are many structures
which may have clocks or clock faces attached to them and some structures have had clocks added to an existing structure. According to the Council on Tall Buildings and Urban Habitat
a structure is defined as a building if at least fifty percent of its height is made up of floor plates containing habitable floor area. Structures that do not meet this criterion, are defined as towers
. A clock tower historically fits this definition of a tower and therefore can be defined as any tower specifically built with one or more (often four) clock faces
and that can be either freestanding or part of a church
or municipal building such as a town hall
. Not all clocks on buildings therefore make the building into a clock tower.
The mechanism inside the tower is known as a turret clock
. It often marks the hour (and sometimes segments of an hour) by sounding large bells
, sometimes playing simple musical phrases or tunes. Some clock towers were previously built as Bell towers
and then had clocks added to them. As these structures fulfil the definition of a tower they can be considered to be clock towers.
Presumably the first depiction of a medieval central European clock tower (without the actual turret clock
) in the 13th century by Villard de Honnecourt
, entitled: "cest li masons don orologe
" ("this is the house of a clock")
Although clock towers are today mostly admired for their aesthetics, they once served an important purpose. Before the middle of the twentieth century, most people did not have watches, and prior to the 18th century even home clocks were rare. The first clocks
did not have faces, but were solely striking clocks
, which sounded bells to call the surrounding community to work or to prayer. They were therefore placed in towers so the bells would be audible for a long distance. Clock towers were placed near the centres of towns and were often the tallest structures there. As clock towers became more common, the designers realized that a dial
on the outside of the tower would allow the townspeople to read the time whenever they wanted.
Clock Tower, Mandi
, HP, India
The use of clock towers dates back to the antiquity
. The earliest clock tower was the Tower of the Winds
which featured eight sundials
. In its interior, there was also a water clock
(or clepsydra), driven by water coming down from the Acropolis
In Song China
, an astronomical clock
tower was designed by Su Song
and erected at Kaifeng
in 1088, featuring a liquid escapement
mechanism. In England, a clock was put up in a clock tower, the medieval precursor to Big Ben
, at Westminster
, in 1288;
and in 1292 a clock was put up in Canterbury Cathedral
The oldest surviving turret clock formerly part of a clock tower in Europe is the Salisbury Cathedral clock
, completed in 1306; and another clock put up at St. Albans
, in 1326, 'showed various astronomical phenomena'.
constructed an elaborate clock and described it in his Book of Knowledge of Ingenious Mechanical Devices
in 1206. It was about 3.3 metres (11 feet) high, and had multiple functions alongside timekeeping
. It included a display of the zodiac
and the solar and lunar paths, and a pointer in the shape of the crescent moon
which travelled across the top of a gateway
, moved by a hidden cart
and causing automatic doors to open, each revealing a mannequin
, every hour.
It was possible to re-program the length of day
daily in order to account for the changing lengths of day and night throughout the year, and it also featured five robotic
musicians who automatically play music when moved by levers
operated by a hidden camshaft
attached to a water wheel
. Other components of the castle clock
included a main reservoir
with a float, a float chamber
and flow regulator
, plate and valve
trough, two pulleys
, crescent disc displaying the zodiac, and two falcon automata
dropping balls into vases
Al-Jazari's castle clock is considered to be the earliest programmable analog computer
Line (mains) synchronous tower clocks were introduced in the United States in the 1920s.
in Birmingham, UK - the tallest freestanding clock tower in the world
Taller buildings have had clock faces added to their existing structure such as the Palace of Culture and Science
, with a clock added in 2000. The building has a roof height of 187.68 m (615.7 ft), and an antenna height of 237 m (778 ft). The NTT Docomo Yoyogi Building
, with a clock added in 2002, has a roof height of 240 m (790 ft), and an antenna height of 272 m (892 ft).
The Abraj Al Bait
, a hotel complex in Mecca
constructed in 2012, has the largest and highest clock face on a building in the world, with its Makkah Royal Clock Tower having an occupied height of 494.4 m (1,622 ft), and a tip height of 601 m (1,972 ft).
The tower has four clock faces, two of which are 43 m (141 ft) in diameter, at about 400 m (1,300 ft) high.
- ^ Joseph V. Noble; Derek J. de Solla Price: The Water Clock in the Tower of the Winds, American Journal of Archaeology, Vol. 72, No. 4 (1968), pp. 345-355 (353)
- ^ a b c Clocks, Encyclopædia Britannica 5, 835 (1951).
- ^ Frederick Tupper, Jr., 'Anglo-Saxon Dæg-Mæl', Publications of the Modern Language Association of America, Vol. 10, No. 2 (1895), p. 130, citing Archæologia, v, 416.
- ^ Howard R. Turner (1997), Science in Medieval Islam: An Illustrated Introduction, p. 184. University of Texas Press, ISBN 0-292-78149-0.
- ^ Donald Routledge Hill, "Mechanical Engineering in the Medieval Near East", Scientific American, May 1991, p. 64-69. (cf. Donald Routledge Hill, Mechanical Engineering Archived December 25, 2007, at the Wayback Machine)
- ^ Salim Al-Hassani (13 March 2008). "How it Works: Mechanism of the Castle Clock". FSTC. Archived from the original on 10 August 2009. Retrieved 2008-09-06.
- ^ Ancient Discoveries, Episode 11: Ancient Robots, History, retrieved 6 September 2008
- ^ "UK Parliament - Big Ben". Retrieved 2009-10-27.
- ^ "Joseph Chamberlain Memorial Clock Tower". Skyscraper News. Retrieved 15 April 2014.
- ^ "National Register of Historic Places Inventory - Nomination Form". (archive) National Park Service. page 10. Retrieved November 9, 2017. "The statue was … hoisted to the top of the tower in fourteen sections in 1894."
- ^ ""History of City Hall: 1886-1890". (archive) Retrieved November 9, 2017. "1889: Mayor Fitler moves into completed offices on west side."
- ^ "History of City Hall: 1891-1901". (archive) Retrieved November 9, 2017. "1891: State Supreme Court opens in permanent courtroom."
- ^ "Makkah Royal Clock Tower ". skyscrapercenter.com. Council on Tall Buildings and Urban Habitat. Retrieved May 20, 2018.
- ^ "Dokaae Tower Clock And Crescent"Archived 2012-03-04 at the Wayback Machine. pct.ae. Premier Composite Technologies. Retrieved May 21, 2018.
Last edited on 25 April 2021, at 07:26
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