17th Century Harbart Silver Verge Watch with Pique Work

• 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.
• Movement - The technical name for the workings of a clock or watch, and does not include the dial or case.
• Tortoiseshell - Tortoiseshell is a translucent material that comes from the horny carapace of a certain types of turtles, including the hawksbill turtle. It is often therefore mounted on a colour underground - often red - or inlaid with gold or silver thread, as seen in Boulle furniture.
  
  The texture and colour nuances of the material are extremely important. Heated tortoiseshell can easily be formed into various shapes. Like other natural materials, tortoiseshell becomes more beautiful with use. In a time before plastic, tortoiseshell was widely used for small objects such as combs and powder compacts.
  
  In 1973, the trade of tortoiseshell worldwide was banned under CITES (The Convention on International Trade in Endangered Species). Prior to importing or exporting items containing tortoiseshell a CITES permit must be obtained. Tortoiseshell items cannot be traded on Ebay.
  
  "Faux tortoiseshell", another case of man initiating nature, is made from old-style plastics such as celluloid and cellulos and is coloured with red, yellow and brown spots to imitate the genuine article. It is commonly used in glasses frames, musical instruments and costume jewellery.
• 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  Use of the fusee in clocks was superseded by the "going barrel" in the mid 19th century and for pocket watches at the beginning of the 19th century.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.
• Pique Work - A decorative technique used on jewellery and small decorative objects in which designs are created by inlaying small gold or silver studs and stips into tortoiseshell. The art reached its highest point in 17th- and 18th-century France, particularly for the decoration of small tortoiseshell articles such as combs, patch boxes, and snuffboxes.
• Pair Cased - A pair cased watch is one with a double case. The movement is encased, and for additional protection this is fitted into an outer case.

This item has been included into following indexes:

• clocks, material or decoration - tortoiseshell cased 99
• pocket watches, case type
  • open face, silver case 514
  • pair cased 143
  • silver case 816
  • silver, open face 192