Louis XVI Style Ormolu Mantle Clock by Constantin Detouche

• Ormolu - Ormolu was popular with French craftsmen in the 18th and 19th century for ornamental fittings for furniture, clocks and other decorative items. True ormolu is gilt bronze, that is bronze that has been coated with gold using a mercury amalgam. Due to the health risks associated with using mercury, this method of creating ormolu was discontinued in France in the 1830s. A substitute was developed consisting of about 75% copper and 25% zinc, however it was inferior to the bronze version. It was often lacquered to prevent it tarnishing.
• 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.
• Emblematic - Serving as a symbol.
• Rustic - Rustic is defined as "of, relating to, or typical of country life or country people", and the items illustrated in this price guide accord with that definition.
  
  But in the 18th and 19th century "rustic furniture" had a narrower definition. It referred to furniture where the framework was carved or moulded to resemble tree trunks and branches, and was usually for outdoor use. Rustic furniture was made in cast iron, wood, terracootta and concrete. Much of the Coalbrookdale company's cast iron furniture was of rustic design.
• 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.
• Acanthus - A stylized leaf motif, one of the primary decorative elements of classical Greek and Roman architecture, derived from the genus of flowering plants in the family Acanthaceae, native to tropical and subtropical regions of the Mediterranean area. It is a common element in classical Greek and Roman design, and is often seen in Corinthian and Composite order columns and used as a decorative element in English, European and Australian furniture, particularly on the curve of a leg, and as decoration for a corbel.

This item has been included into following indexes:

• clocks, mantle & shelf, material or style - gilt metal / ormolu 536
• clocks, mantle & shelf, period or origin - French 737