A regulator clock is a highly accurate timepiece, usually used for making precise measurements in conjunction with astronomical observation. This part is from a clock made by Benjamin Vulliamy (1780-1854) for George III which was used as the principal timekeeper at the King's Observatory in Richmond. Friction rollers act as the bearings of the wheelwork, reducing the need for lubrication. The clock was fitted with the almost frictionles 'grashopper' escapement invented by the pioneer of the chronometer, John Harrison (1693-1776). Harrison's gridiron' pendulum was also incorporated to ensure the clock kept good time, compensating for changes of temperature in the Observatory.
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