Salisbury Cathedral Clock - History

History

A clock in Salisbury Cathedral that struck the hours was mentioned in 1306. This was probably one of the precursors of the 1386 clock, one of the many early examples of mechanical water clocks that are mentioned from c. 1280 onwards.

The clock was found in the cathedral in 1928. It had a pendulum, which appeared to have been installed at a later date. The clock was restored in 1956, and a verge escapement and foliot were installed. There were no drawings or documents available, so it is unlikely that the original foliot and verge escapement looked exactly like the one now installed in the clock.

The striking train of the clock is believed to be original.

Like many of these more practical devices, its main purpose was to strike a bell at precise times. It probably did not have a dial. The wheels and gears are mounted in a four-post wrought iron frame. The framework was not held together with nuts and bolts (which had not been invented), but rather with metal wedged tenons.

The escapement was a verge escapement with a foliot, standard for clocks of this age. The power was supplied by two large stone weights. As the weights descend, ropes unwind from the wooden barrels. One barrel drives the going train which is regulated by the escapement, the other drives the striking train whose speed is regulated by the fly (air brake).

Before the weights reach the floor, they have to be wound back up again, a task that explains the presence of two large wheels shaped like steering wheels at either end of the clock.

The clock was a 'single strike' clock that struck only on the hour. It made one strike per hour of the day (e.g. 12 strikes at noon). The left half of the clock (as in the photograph above), is the striking train; the right half is the going train.

At the end of the 17th century, the Salisbury clock, like many others, was modified from verge and foliot to pendulum and anchor operation. This usually made clocks much more accurate, even though trials in the early 1990s by Michael Maltin showed that the clock was running to within two minutes a day if the rope on the barrel was kept in a single layer. As soon as there are two layers, there is more torque applied to the barrel by the weight and the clock will go faster. As a single layer of winding is enough to keep the clock going for 12 hours, it could have been kept exact to within 2 minutes per day if it had been wound twice per day.

In 1790, the old bell tower 'on the ditch of the close of the canons of the said church' mentioned in the deed of 1386 which had housed the clock was demolished, so the clock was moved to the Cathedral's central tower. In 1884, a new clock was installed and the old one was left to the side.