Image: Salisbury Cathedral 2012 12

Description: Detail of Salisbury cathedral clock at Salisbury Cathedral, UK. Built sometime around 1386, this is one of the oldest mechanical clocks in the world. This picture shows the verge escapement (crown shaped vertical wheel) which drove the foliot, (horizontal bar with hanging weights at top) to oscillate back and forth, to keep time for the clock. The invention of the verge and foliot sometime in the late 1200s was the crucial technological advance which led to the development of mechanical clocks. Unfortunately due to the improved accuracy of the pendulum, invented in 1657, almost all clocks from the medieval era were modified to replace the foliot by a pendulum. This clock was found with a pendulum, the foliot seen at top is a modern imitation restored in 1956.
Title: Salisbury Cathedral 2012 12
Credit: Own work
Author: Photograph by Mike Peel (www.mikepeel.net).
Permission: CC-BY-SA-4.0. Please attribute as per the author line above.
Usage Terms: Creative Commons Attribution-Share Alike 4.0
License: CC BY-SA 4.0
License Link: https://creativecommons.org/licenses/by-sa/4.0
Attribution Required?: Yes