Empire-style Mantel Clock by C.F. Petit, Paris

• Movement - The technical name for the workings of a clock or watch, and does not include the dial or case.
• Empire Style - The Empire style was a version of neo-classicism popular from 1800 to 1830, coinciding with the rule of Napoleon I from 1840-15. In England the style corrosponds with the Regency style and in the United States to the Federal style.
  
  The style is inspired by classical Rome and Greece, as reflected in the decorative motifs in the the design such as paterae, guilloches, acanthus and swags, and pieces are lavishly decorated with applied gilded decoration.
• 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, mantle & shelf, material or style - gilt metal / ormolu 547
• clocks, mantle & shelf, period or origin - French 761
• clocks, type - portico 191