Thomas Utting Silver and Tortoiseshell Pair Cased Watch

• 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.
• 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.
• Barrel (in a Clock) - In a clock or watch, the barrel is a cylindrical component that stores the energy from the mainspring. As the mainspring is wound, it stores energy in the barrel. As the clock or watch runs, the energy is gradually released from the barrel, turning the clock's gears and keeping the time.
  
  The barrel is typically located near the centre of the movement (the mechanism that powers the clock) and is connected to the center wheel, which drives the rest of the gears. The barrel typically has teeth on its outer surface that mesh with the gears in the movement, allowing it to transmit energy to the rest of the clock. Some barrels are designed to be wound by hand, while others are automatically wound by the motion of the wearer's arm.
• Foliate - Decorated with leaves or leaf-like forms.
• 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.
• 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.

This item has been included into following indexes:

• clocks, material or decoration - tortoiseshell cased 105
• pocket watches, case type
  • pair cased 156
  • silver case 865
• pocket watches, period - Georgian 258