how does the fourth one function?
Works under the rack and snail striking mechanism
Striking clock
This describes how the rack and snail striking mechanism works. 
who invented the first mechanical clock in 1300 Catholic monks which of the earliest civilizations used timekeeping devices? Hunter-gatherers, Prehistoric Europe, Mesoamericans, etc why did the monks invent the clock? To regulate daily prayer- and work-schedules strictly and to ensure accuracy can you give me examples of timekeeping devices? Astronomical bodies, sticks and bones to track the phases of the moon or the seasons, Stone circles, sexagesimal timekeeping, and vigesimal counting system name some of the innovations during the medieval period Clock, wristwatches, Clock of the Long Now, mechanical clock, and pendulum clock did ancient egypt use timekeeping devices? Yes, Shadow clocks and Sundials what about greece? They used water clocks, or clepsydrae, and water-based alarm clock name some of the innovations during the pre-modern period Mechanical clocks and pendulum clock is it possible to keep track of time underwater? Yes, by Marine chronometers how did the persians keep track of time? By using water clocks what device did the chinese invent to keep track of time? Outflow and inflow clepsydra is there an industry now that deals specifically with time keeping devices? Yes, clock and watch-making industry who invented the wristwatch? UNANSWERABLE what are the different types of clocks? Sundial, hourglass, water clocks, striking clock, watches, pendulum clock, and electric clock how does the first one work? It uses the Sun's altitude or azimuth (or both) to show the time. who invented the second one? Its origin is unclear
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Striking clock [SEP] How it works
This describes how the rack and snail striking mechanism works. The labels refer to the drawing above. The release lever "(L)" holds the rack "(M)" up when the clock is not striking. On the shaft of the minute hand (not shown), which rotates once per hour, there is a projection. As the change of the hour approaches, this projection slowly lifts the release lever, allowing the rack to fall until its point rests on the snail "(N)". The amount the rack can fall, and thus the number of strikes, is determined by the position of the snail. Exactly on the hour the striking train "(G, H, K)" is released and begins to turn.