The Antikythera mechanism was an arrangement of calibrated differential gears inscribed and configured to produce solar and lunar positions in synchronization with the calendar year. By rotating a shaft protruding from its now-disintegrated wooden case, its owner could read on its front and back dials the progressions of the lunar and synodic months over four-year cycles. He could predict the movement of heavenly bodies regardless of his local government's erratic calendar. From the accumulated inscriptions and the position of the gears and year-ring, Price deduced that the device was linked closely to Geminus of Rhodes, and had been built on...