Charles X Marquetry Portico Clock

• 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.
• Frieze - An architectural term denoting the flat, shaped or convex horizontal surface of furniture, between the architrave and the cornice, usually found on a cabinet or bookcase, or on desks and tables where it may include drawers, the area between the top and the legs. In ceramics, the term refers to the banding, of usually a repeating pattern, on the rims of plates and vases.
• Engine Turned - Engine turning is a decorative technique used on metal surfaces to create intricate curving or geometric pattern. The process involves cutting a series of lines into the surface of the metal using a rose engine or decoration lathe which rotates the metal as it cuts, allowing the operator to create a repeating pattern that covers the entire surface. The resulting surface has a shimmering, reflective quality that is often described as "engine turned." Where an engine turned item has been enamelled, the term used to describe the decoration is usually guilloche.
  
  Engine turning was originally developed to decorate metal objects such as firearms, scientific instruments, and other metal objects that required precise and elegant design.
• 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.

This item has been included into following indexes:

• clocks, type - portico 193