The first precise timekeeping mechanism, whose principles of motion were discovered by Galileo, was the simple pendulum (see below). The accuracy of modern timekeeping has been improved dramatically by the introduction of tiny quartz crystals, whose harmonic oscillations generate electrical signals that may be incorporated into miniaturized circuits…
From the 14th century, some clock towers in Western Europe were also capable of chiming at a fixed time every day; the earliest of these was described by the Florentine writer Dante Alighieri in 1319. The most famous original striking clock tower still standing is possibly the one in St Mark's Clocktower in St Mark's Square, Venice. The St Mark's Clock was assembled in 1493, by the famous clockmaker Gian Carlo Rainieri from Reggio Emilia, where his father Gian Paolo Rainieri had already constructed another famous device in 1481. In 1497, Simone Campanato moulded the great bell (h. 1,56 m., diameter m. 1,27), which was put on the top of the tower where it was alternatively beaten by the Due Mori (Two Moors), two bronze statues (h. 2,60) handling a hammer.
Simple clocks intended mainly for notification were installed in towers, and did not always require faces or hands. They would have announced the canonical hours or intervals between set times of prayer. Canonical hours varied in length as the times of sunrise and sunset shifted. The more sophisticated astronomical clocks would have had moving dials or hands, and would have shown the time in various time systems, including Italian hours, canonical hours, and time as measured by astronomers at the time. Both styles of clock started acquiring extravagant features such as automata.
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