French Onyx Mantle Clock with Gilt Brass Accents

• Movement - The technical name for the workings of a clock or watch, and does not include the dial or case.
• 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.
• Finial - An architectural decoration, found on the upper parts of of an object. On furniture they are usually found on pediments, canopies and shelf supports. On smaller ceramic or silver items, such as spoons, they may decorate the top of the item itself, or the lid or cover where they provide a useful handle for removal.
  
  Finials have a variety of shapes and forms. They may be urn-shaped, baluster shaped round or spiral, but usually taper into an upper point. Many real life shapes may also be used as finials, such as pineapples, berries, pinecones, buds, lotus and acorns. Sometimes animals such as a lion are depicted, or fish and dolphins.
• Onyx - Onyx is a form of agate, used from antiquity and popular again in the 1920s and 30s. European onyx is generally green, but can be many other colours, and can contain bands of black and/or white.
  
  This multicoloured stone is widely used for table tops, lamp bases and in jewellery. Some types of onyx are also used for cameos of which the upper white layer is cut away to reveal the colour beneath.

This item has been included into following indexes:

• clocks, material or decoration
  • marble or slate 430
  • onyx 30