Along with several others, the Salisbury Cathedral clock is claimed to be “the oldest working clock in the world”. The clock is dated from 1386 and was originally housed in a bell tower next to the cathedral itself. The bell tower was demolished in 1790 and the clock moved to the cathedral tower where it continued to operate until 1884. A new clock was contributed to the cathedral by the Wiltshire Army Regiment in 1884 and the old lock was left to gather dust until 1928 when it was “rediscovered” by horologist T. R. Robinson. In 1956 the clock was restored to its original condition and operation with a new verge and foliot (oscillating bar) escapement.
The clock mechanism is housed in a wrought iron frame 1.24 m high by 1.29 m wide. Viewed from the front, to going train (timekeeping) is on the right and the striking train is on the left. Each side is powered by a rotating drum attached through ropes and pulleys to stone weights. The speed of the going train rotation is governed by the verge and foliot escapement while the striking train rotation is controlled by the flywheel or air brake. As the clock only strikes on the hour, the striking train is locked for most of each hour. At the top of each hour a pin on the great wheel of the going train rotates the bar on the back of the clock that unlocks the great wheel of the striking train and allows the count wheel to control the number of strikes for that hour. Each strike is governed by the eight pins on the great wheel of the striking train, e.g. at four o’clock, the great wheel rotates through 180 degrees so that the striking lever is pulled up and released four times resulting in four chimes of the bell in the tower above. When the hour strike is complete, the striking train is once again locked.
