Napoleon III Boulle Clock with Gilt Bronze and Tortoiseshell Case

• Foliate - Decorated with leaves or leaf-like forms.
• Bronze - An alloy of copper and tin, traditionally in the proportions of about 9 parts of copper to 1 part of tin.
  
  The discovery of bronze in Western Asia in the 4th century enabled people to create metal objects which were superior to those previoulsy possible because of its strength and hardness, and it has been used throughout the world for weapons, coins, tools, statuary and other decorative items.
  
  It is very fluid in a molten state, and its hardness, strength when set, and non-corrosive properties makes it most suitable for casting sculpture.
• Pendulum - The pendulum was discovered around 1602 by Galileo Galilei, and was adopted for time keeping by the Dutch mathematician and natural philosopher, Christiaan Huygens, who excelled in astronomy, physics, and horology.
  
  The pendulum comprises a metal rod usually of brass or steel with a metal disk, known as a bob, at the end. The movement of the pendulum is driven by weights or a spring, and as a pendulum swings in a regular arc, it was found accuracy could be controlled to within a few seconds a week.
  
  Timekeeping can be adjusted by changing the height of the bob on the rod, making the pendulum either swing slower or faster.
  
  The disadvantage of the pendulum was that changes in temperature also changed the length of the pendulum, interfering with the accuracy of the clock, and so in the 18th century two types of mercurial pendulums were invented which countered the movement in the steel rod.
  
  The pendulum was the world's most accurate timekeeping technology until the invention of the quartz clock, regulated by a quartz crystal, in 1927.
• Boulle - Boulle work is the name given to tortoiseshell and metal inlay using brass and sometimes silver, found on furniture and smaller wooden objects. It originated in Italy but was developed by Frenchman Andre Charles Boulle (1642 - 1732) under Louis XIV.
  
  Boulle was appointed Royal Cainet Maker to Louis XIV and designed furniture and clockcases for the monarch.
  
  In preparation, the tortoiseshell and metal were cut together following a design, using a fine fret saw.
  
  In the application of the Boulle, the carcase of piece of furniture was covered with the tortoiseshell which in turn was inlaid with the matched designs in metal, which in turn was elaborately engraved.
  
  The use of Boulle work furniture continued mainly in France until the 19th century.
• 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.

This item has been included into following indexes:

• clocks, mantle & shelf, material or style - gilt metal / ormolu 548
• clocks, mantle & shelf, period or origin - French 762
• clocks, material or decoration
  • Boulle 97
  • tortoiseshell cased 106