Ebonised Bentley & Beck Royal Exchange Bracket Clock

• Anchor Escapement - An anchor escapement is a type of mechanical escapement used in clocks and watches. It is a refinement of the older verge escapement, which was used in early mechanical timekeeping devices. The anchor escapement is characterised by the use of an anchor-shaped pallet that rocks back and forth, alternately locking and releasing the escape wheel. This action allows the movement of the watch or clock to be regulated, producing the characteristic tick-tock sound that is associated with mechanical timekeeping devices. The anchor escapement is generally more accurate and reliable than the verge escapement, and it is still used in many modern clocks and watches today.
• George Iii - George III (1738 - 1820) was King of Great Britain and Ireland from 1760 to 1820.
• Back Plate - On many types of clocks, the movement operates between two plates, usually made of brass, one at the back, and the other at the front, which forms a mount for the dial.
  
  On English bracket, mantle and table clocks the backplate was often visible through a glass door or panel from the late 17th century, and could be profusely engraved with scrolling decorations, flowers, foliage, birds, and figures. The engraving could also include the maker?s name.
  
  The amount of engraving reduced and became simpler as the 18th century progressed, and by 1800, had been reduced to a border, often with the maker's name in the centre. By the early 1800s all decoration had ceased, and only the maker's name was added, and by the Victorian era, most bracket, mantle and table clocks had no engraving.
• 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.
• Movement - The technical name for the workings of a clock or watch, and does not include the dial or case.
• Fusee - The fusee movement was used in clocks and pocket watches from the mid 17th century. The fusee is a cone shaped drum within the works that is linked to the barrel of the spring, usually by a length of chain.
  
  As the mainspring loses its tension over time, the cone shaped barrel compensates for this by increasing the tension, by pulling the mainspring tighter, thus ensuring the time remains constant.
  
  Use of the fusee in clocks was superseded by the "going barrel" in the mid 19th century and for pocket watches at the beginning of the 19th century.
  
  The fusee continued to be used in marine chronometers until the 1970s.

This item has been included into following indexes:

• clocks, type - bracket 328