CENTER SECONDS OR SWEEP SECONDS—A long seconds hand moved from the center of a watch dial, as are the minute and hour hands.
CENTER STAFF—The arbor attached to the center wheel which carries the minute hand.
CENTER WHEEL—The wheel in ordinary clocks and watches placed in the center of the frame on whose arbor the minute hand is carried. It is intermediate between the barrel and the third wheel.
CHAMFER—To cut away to a bevel the right angle formed by two adjacent faces as of a jewel or stone. It is also occasionally used to signify channeling or grooving.
CHASING—A form of ornament for metals which is made by punching or pressing from behind to present the pattern in relief instead of by cutting away the material.
CHOPS—In a pendulum clock the blocks, usually of brass, between which the top of the pendulum suspension spring is clipped to prevent its twisting as it swings.
CHRONOGRAPH—In general, a recording clock or watch. Specifically, a watch with a center-seconds hand which may be stopped, started or returned to zero at will by pressing a button. Used for timing races, or measuring other short spaces of time with great exactness.
CHRONOMETER—Any very accurate time-keeper. Usually understood to mean a time-keeper fitted with a spring detent escapement. They usually have a fusee and a cylindrical balance spring.
CHRONOMETER, MARINE—Probably the most exact form of time-keeper, especially for use on shipboard. The driving power is a mainspring acting by a chain on a fusee, and governed by what is known as the Chronometer or Detent Escapement, with, as a rule, the cylindrical balance spring. The movement is mounted on gimbals in an air and water-tight brass case, maintaining the dial constantly in a horizontal position.
CHRONOSCOPE—A clock or watch in which the time is shown by figures presented at openings in the dial.
CHURCH, DUANE H.—Credited with having contributed more to the automatic features of watch machinery than any other man. He was born in Madison County, N. Y., in 1849. At 16 he was apprenticed to a watchmaker of St. Paul, Minn., and after working at the trade for 17 years, he became in 1882 the master watchmaker for the Waltham Watch Company. Besides his invaluable contributions to automatic machinery, he improved the general design of watch movements and invented a form of pendant setting which enables stem-winding movements to be set in cases not especially adapted to them. He died in 1905.