timekeeping part, and installed parallel to it, on the left side as one faces the clock. Regulator – A device to prevent the striking train from running too fast, and control the speed of striking. If it wasn't present, the striking train when released would run out of control under the force of the spring or weight. In most clocks it is a simple fly fan (or fan fly) (K), a flat piece of sheet metal mounted on the fastest turning gear shaft. When the striking train turns, this beats the air, and the air friction limits the speed of the train. Striking watches and some modern clocks use a centrifugal governor instead. Count mechanism – This is the critical part mentioned above, that releases the striking train at the proper time and counts out the proper number of strikes. It is the only part of the striking mechanism that is attached to the clock's timekeeping works. Virtually all modern clocks use the rack and snail. The snail (N) is usually mounted on the clock's center wheel shaft, which turns once every 12 hours. There is also a release lever (L) which on the hour releases the rack and allows the timing train to turn. Hammer and gong – The hammer lever (F) is actuated by pins or teeth (G) on one of the striking train wheels. As the wheel turns the pin lifts the hammer lever, until the lever slips off the pin, allowing the hammer to drop, hitting the gong (E). Early house clocks used traditional hemispherical shaped bells. Later house clocks used gongs made of long steel tubes or bars, which have a sound more like large church bells. Mantel and other small clocks use thick hardened steel wires, which are coiled into a spiral to save space. Clocks that have more elaborate functions than just striking the hours, such as chiming the quarter hours, or playing tunes, are called "chiming clocks" by clockmakers. The additional functions are usually run by a second complete striking mechanism separate from the (hour) striking train, called the "chiming train". These clocks have three weights or mainsprings, to power the timing train, striking train, and chiming train. 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