Editing Clock (section)

===Astronomical===

[[File:Abbot Richard Wallingford.jpg|thumb|right|[[Richard of Wallingford]] pointing to a clock, his gift to [[St Albans Abbey]]]]

[[File:Clock machine 16th century-Convent of Christ,Tomar, Portugal.jpg|thumb|16th-century clock machine [[Convent of Christ]], [[Tomar]], Portugal]]

An elaborate water clock, the 'Cosmic Engine', was invented by [[Su Song]], a Chinese [[polymath]], designed and constructed in China in 1092. This great astronomical hydromechanical clock tower was about ten metres high (about 30 feet) and was indirectly powered by a rotating wheel with falling water and [[Mercury (element)|liquid mercury]], which turned an [[armillary sphere]] capable of calculating complex astronomical problems.

In Europe, there were the clocks constructed by [[Richard of Wallingford]] in [[St Albans|Albans]] by 1336, and by Giovanni [[Giovanni Dondi dell'Orologio|de Dondi]] in [[Padua, Italy|Padua]] from 1348 to 1364. They no longer exist, but detailed descriptions of their design and construction survive,<ref name="north">North, John. God's Clockmaker: Richard of Wallingford and the Invention of Time. London: Hambledon and London (2005).</ref><ref name="king">King, Henry "Geared to the Stars: the evolution of planetariums, orreries, and astronomical clocks", University of Toronto Press, 1978</ref> and modern reproductions have been made.<ref name="king" /> They illustrate how quickly the theory of the mechanical clock had been translated into practical constructions, and also that one of the many impulses to their development had been the desire of astronomers to investigate celestial phenomena.

The Astrarium of Giovanni Dondi dell'Orologio was a complex astronomical clock built between 1348 and 1364 in [[Padua]], Italy, by the doctor and clock-maker [[Giovanni Dondi dell'Orologio]]. The Astrarium had seven faces and 107 moving gears; it showed the positions of the Sun, the Moon and the five planets then known, as well as religious feast days. The astrarium stood about 1 metre high, and consisted of a seven-sided brass or iron framework resting on 7 decorative paw-shaped feet. The lower section provided a 24-hour dial and a large calendar drum, showing the fixed feasts of the church, the movable feasts, and the position in the zodiac of the Moon's ascending node. The upper section contained 7 dials, each about 30&nbsp;cm in diameter, showing the positional data for the [[Primum Mobile]], Venus, Mercury, the Moon, Saturn, Jupiter, and Mars. Directly above the 24-hour dial is the dial of the [[Primum Mobile]], so called because it reproduces the diurnal motion of the stars and the annual motion of the Sun against the background of stars. Each of the 'planetary' dials used complex clockwork to produce reasonably accurate models of the planets' motion. These agreed reasonably well both with Ptolemaic theory and with observations.<ref>{{Cite web |title=Giovanni Dondi's Astrarium, 1364 {{!}} cabinet |url=https://www.cabinet.ox.ac.uk/giovanni-dondis-astrarium-1364-0 |access-date=2022-06-05 |website=www.cabinet.ox.ac.uk |archive-date=November 20, 2021 |archive-url=https://web.archive.org/web/20211120141134/https://www.cabinet.ox.ac.uk/giovanni-dondis-astrarium-1364-0 |url-status=live }}</ref><ref>{{Cite news |last=Abrams |first=Melanie |date=2018-02-16 |title='The Beauty of Time' |language=en-US |work=The New York Times |url=https://www.nytimes.com/2018/02/16/style/watches-clocks-mbandf-breuget.html |access-date=2022-06-05 |issn=0362-4331 |archive-date=June 4, 2022 |archive-url=https://web.archive.org/web/20220604212633/https://www.nytimes.com/2018/02/16/style/watches-clocks-mbandf-breuget.html |url-status=live }}</ref>

Wallingford's clock had a large astrolabe-type dial, showing the Sun, the Moon's age, phase, and node, a star map, and possibly the planets. In addition, it had a [[Rota Fortunae|wheel of fortune]] and an indicator of the state of the tide at [[London Bridge]]. Bells rang every hour, the number of strokes indicating the time.<ref name="north"/> Dondi's clock was a seven-sided construction, 1 metre high, with dials showing the time of day, including minutes, the motions of all the known planets, an automatic calendar of fixed and [[Moveable feast|movable feast]]s, and an eclipse prediction hand rotating once every 18 years.<ref name="king"/> It is not known how accurate or reliable these clocks would have been. They were probably adjusted manually every day to compensate for errors caused by wear and imprecise manufacture. Water clocks are sometimes still used, and can be examined in places such as ancient castles and museums. The [[Salisbury Cathedral clock]], built in 1386, is considered to be the world's oldest surviving mechanical clock that strikes the hours.<ref>Singer, Charles, et al. ''Oxford History of Technology: volume II, from the Renaissance to the Industrial Revolution'' (OUP 1957) pp. 650–651</ref>