Graham invents the mercury pendulum In 1721, George Graham invented the mercury pendulum – a temperature-compensated pendulum designed to overcome the limiting effects of temperature fluctuation on pendulums. Graham’s mercury pendulum was so named because it had a bob that also functioned as a container for the liquid metal mercury. The gridiron pendulum that John Harrison invented in 1726 was also a temperature compensated pendulum designed to solve the same problem. Image Credit: Mercury pendulum from the eight-day duration mahogany longcase regulator by George Graham, London, c.1750, known as 'Graham No. 3'. ID: ZBA0709. National Maritime Museum, Greenwich, London, CC BY-NC-ND 3.0, https://www.rmg.co.uk/collections/objects/rmgc-object-203202
