Hunter, George—Identified with watchmaking in America since about 1860—in the Waltham and Elgin Companies. He was general superintendent of the latter from 1872 to 1903, after which he was made consulting superintendent.
Huyghens, Christian—A celebrated Dutch astronomer and mathematician born at The Hague, April 14, 1629. Although the honor is claimed for Richard Harris in 1641 and for Vincent Galileo in 1649 it seems historically established that Huyghens in 1657 was the first to apply to clocks the theory of the isochronism of the pendulum which the great Galileo had discovered. In 1669 he published his important work, "Horologium Oscillatorium." In 1673 he made the first clock with concentric hour and minute hands. He died in 1695.
Huyghens' Checks—The arc of a swinging pendulum is a segment of a circle. For perfect isochronism it should be a cycloidal segment. To accomplish this Huyghens fixed curved brass pieces called checks for the cord to strike against but he caused thereby a greater error than he remedied. This end was later accomplished by suspending the pendulum by means of a flat steel strip instead of a cord; a device credited to Robert Hooke.
Hypocycloid—A curve generated by any point in the circumference of a circle which is rolled on the inner side of the circumference of a larger fixed circle.
Idler, Idle Wheel, or Intermediate Wheel—A toothed wheel used to connect driver and follower wheels so that both shall rotate in the same direction.
Impulse—The push transmitted to the pallet by the escape wheel.