Introduction
There was a mechanical clock working in Milan by 1335. It is the first for which there is firm evidence although there are suggestions that there were some mechanical clocks in existence before 1300. By 1350, several mechanical clocks were working in Italy. The oldest surviving mechanical clock in Britain and probably anywhere was installed in Salisbury Cathedral in 1386. By 1392 another mechanical clock was installed at Wells Cathedral.
The mechanism for the Well's clock was replaced in 1838. However the original is now in the Science Museum, along with steel bells added in the 1880s.
| The Wells Cathedral clock on display in the Science Museum: It is the second oldest public clock in Britain. � Science Museum/Science & Society Picture Library |
Mechanical clocks brought about a change in the way in which time was measured. Before the 14th century, the system of dividing a period of one day and one night into 24 equal hours was only used by astronomers. For most people, the periods of daylight and darkness were each divided into 12 "temporal hours", which varied in length throughout the year. This is convenient with sundials but the speed of a mechanical clock does not vary in this way. By the end of the 15th century, most people in Europe had switched to the modern system and the design of sundials had changed to use it as well.
