Joseph Foster Silver Verge Striking Watch, London, c. 1700

• Circa - A Latin term meaning 'about', often used in the antique trade to give an approximate date for the piece, usually considered to be five years on either side of the circa year. Thus, circa 1900 means the piece was made about 1900, probably between 1895 and 1905. The expression is sometimes abbreviated to c.1900.
• Bezel - On a clock or watch, the bezel is the metal frame into which the watch or clock glass is fitted. In clocks, the bezel may include a hinge and a flange, in effect a door to the face of the clock. In jewellery the bezel is a band of metal with a projecting lip that holds the gemstone in its setting.
• Movement - The technical name for the workings of a clock or watch, and does not include the dial or case.
• Verge Escapement - A verge escapement is an early mechanical escapement used in clocks and other timekeeping devices. It is an early form of the escapement mechanism, which is used to regulate the movement of the hands of a clock or watch. The verge escapement consists of a vertical shaft called the verge, which is mounted on the clock's main plate. Attached to the verge are two pallets, which engage with the teeth of the escape wheel. As the escape wheel turns, the pallets alternately lock and release it, allowing the movement of the clock to be regulated. The verge escapement was widely used in early mechanical clocks, but it was eventually replaced by the more accurate and reliable anchor escapement.
• Chapter Ring - A separate metal plate on the face of a clock, on which the numerals for the hours and sometimes parts of the hours, are displayed, usually wheel shaped and sitting on top of the dial plate. The chapter ring is often a feature of the clock and can be silvered or enamelled to stand as a contrast to its background. The hours are usually shown in Roman numerals, although in the late 19th and earlt 20th century, Arabic numerals became fashionable.
• Fusee - The fusee movement was used in clocks and pocket watches from the mid 17th century. The fusee is a cone shaped drum within the works that is linked to the barrel of the spring, usually by a length of chain.
  
  As the mainspring loses its tension over time, the cone shaped barrel compensates for this by increasing the tension, by pulling the mainspring tighter, thus ensuring the time remains constant.
  
  Use of the fusee in clocks was superseded by the "going barrel" in the mid 19th century and for pocket watches at the beginning of the 19th century.
  
  The fusee continued to be used in marine chronometers until the 1970s.
• Foliate - Decorated with leaves or leaf-like forms.

This item has been included into following indexes:

• pocket watches, case type
  • open face, silver case 514
  • pair cased 143
  • silver case 816