Orrery

The orrery was named for Charles Boyle, the fourth Earl of Orrery, who commissioned clockmaker John Rowley to build a mechanical model of the solar system around 1713. The device used gears and clockwork to show the relative motions of the planets and moons. George Graham had built the prototype. Rowley improved it and dedicated the improved version to the Earl. The Earl's name stuck. Graham's and Rowley's did not.

Mechanical models of the heavens are far older than the word. The Antikythera mechanism, a Greek bronze device found in a shipwreck off the Greek island of Antikythera, dates to approximately 100 BCE and used gears to predict eclipses and planetary positions. It was a hand-cranked orrery built two thousand years before the word existed. When it was recovered in 1901, no one immediately understood what it was.

Orreries became fashionable in the eighteenth century as demonstrations of the Newtonian solar system. Wealthy collectors commissioned elaborate versions with ivory planets and brass gears. Scientific instrument makers like Benjamin Martin and James Ferguson built orreries for public lectures. The devices served the same purpose as a modern planetarium show: making the abstract motions of the solar system visible and mechanical.

The word 'orrery' is unusual because it names a scientific instrument after a patron rather than an inventor or a principle. Telescopes, barometers, and thermometers are named for what they do. The orrery is named for who paid for it. This pattern — the patron's name outlasting the maker's — was common in the eighteenth century. The Earl of Orrery's title came from the town of Orrery in County Cork, Ireland. An Irish town named a device that models the solar system.