Barrel—A circular box which confines the mainspring of a watch or clock.
Barrel Arbor—The axis of the barrel around which the mainspring is coiled.
Barrel Hollow—A sink cut either into the top plate or the pillar plate of a watch to allow the barrel freedom.
Barrel Hook—A bent pin in the barrel to which the mainspring is attached.
Barrel Ratchet—A wheel on the barrel arbor which is prevented by a dog from turning backward while the mainspring is being wound and which becomes the base against whose resistance the train is driven.
Bartlett, P. S.—One of the early watchmakers of America. Connected with the Waltham factory at first and later with the Elgin Company. It is said that he first proposed the formation of the company at Elgin. His name became familiar as a household word throughout the country from being inscribed upon a full-plate model which attained widespread success.
Beat—The strike or blow of the escape wheel upon the pallet or locking device.
Beat Pins—The pins at the ends of the pallets in a gravity escapement which give impulse to the pendulum.
Beckett, Sir Edmund—See [Denison], Edmund Beckett.
Berosus—A Chaldean historian who lived at the time of Alexander the Great, about 200 B. C., and was a priest of Belus at Babylon. Said to have been the inventor of the hollow sun-dial. He was the great astronomer of his age.