Adams, J. C.—A promoter instrumental in organizing the Elgin, Illinois, Cornell, and Peoria Watch Companies, and the Adams & Perry Manufacturing Company. He invented and patented the "Adams System" of time records in use on most of the railroads in the West. He last appeared in prominent connection with the watch and clock business as the organizer of the Swiss horological exhibit at the World's Columbian Exposition.
Addenda—Tips of the teeth of a wheel beyond the pitch circle. Sometimes of circular outline; sometimes ogive—that is, of a shape patterned after the pointed arch. The addendum is also known as the "face" of the tooth.
Adjustment—The manipulation of the balance with its spring and staff to secure the most accurate time-keeping possible. Three adjustments are usually made, viz.: for isochronism, temperature and position. Much of the difference in value and cost of watches depends on this operation.
Adjustment to Isochronism—Strictly speaking this would cover all adjustment; but it is technically understood to mean an adjustment of the balance spring so that the time of vibration through the long and short arcs of the balance is the same.
Adjustment to Positions—The manipulation of the balance and its spring so that a watch keeps time in different positions. Good watches are usually adjusted to five positions. They are pendant up; III up; IX up; dial up; and dial down.
Adjustment to Temperature or Compensation—The adjustment of the balance and spring so that the time-keeping qualities are affected as little as possible by changes in temperature. See [Compensation].
Ahaz—King of Judea, 742-727 B. C. See [Dial of Ahaz].
Alarm—Sometimes spelled "alarum." A mechanism attached to a clock whereby at any desired time a bell is struck rapidly by a hammer.
Aluminum-Bronze—An alloy of aluminum and pure copper, usually in the proportion of 10 parts of the former and 90 of the latter. It is considerably lighter than brass and highly resistant to wear.
Anaximander—Greek astronomer to whom the Greeks ascribed the invention of the sun-dial in the sixth century B. C.