The
ancient Greek philosopher
Plato (428–348 BCE) was said to possess a large
water clock with an unspecified alarm signal similar to the sound of a
water organ; he used it at night, possibly for signaling the beginning of his lectures at dawn (
Athenaeus 4.174c). The
Hellenistic engineer and inventor
Ctesibius (
fl. 285–222 BCE) fitted his clepsydras with dial and pointer for indicating the time, and added elaborate "alarm systems, which could be made to drop pebbles on a gong, or blow trumpets (by forcing bell-jars down into water and taking the compressed air through a beating reed) at pre-set times" (
Vitruv 11.11). The
late Roman statesman
Cassiodorus (c. 485–585) advocated in his rulebook for monastic life the water clock as a useful alarm for the "soldiers of Christ" (Cassiod. Inst. 30.4 f.). In China, a striking clock was devised by the
Buddhist monk and inventor
Yi Xing (683–727). The Chinese engineers
Zhang Sixun and
Su Song integrated striking clock mechanisms in astronomical clocks in the 10th and 11th centuries, respectively. A striking clock outside of China was the water-powered clock tower near the
Umayyad Mosque in
Damascus,
Syria, which struck once every hour. It is the subject of a book,
On the Construction of Clocks and their Use (1203), by
Riḍwān ibn al-Sāʿātī, the son of clockmaker. In 1235, an early monumental water-powered alarm clock that "announced the appointed
hours of prayer and the time both by day and by night" was completed in the entrance hall of the
Mustansiriya Madrasah in
Baghdad. 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. User-settable mechanical alarm clocks date back at least to 15th-century Europe. These early alarm clocks had a ring of holes in the clock dial and were set by placing a pin in the appropriate hole. The first American alarm clock was created in 1787 by
Levi Hutchins in
Concord, New Hampshire. This device he made only for himself, however, and it only rang at 4 am, to wake him for his job. The French inventor Antoine Redier was the first to patent an adjustable mechanical alarm clock, in 1847. Alarm clocks, like almost all other consumer goods in the United States, ceased production in the spring of 1942, as the factories which made them were converted over to war work during
World War II, but they were one of the first consumer items to resume manufacture for civilian use, in November 1944. By that time, a critical shortage of alarm clocks had developed due to older clocks wearing out or breaking down. Workers were late for, or missed completely, their scheduled shifts in jobs critical to the war effort. The price of these "emergency" clocks was, however, still strictly regulated by the Office of Price Administration. == Alarms in technology ==