George III Mahogany Balloon Clock by Francis Perigal

• Boxwood - Boxwood is a hard, yellow coloured, close grained timber. In the 19th century it was often used for inlays, especially stringing, because of its contrasting colour to the darker timbers of the carcase. Stringing is the inlay of a narrow strip of veneer of a lighter colour, such as boxwood along or close to the edges of an object that has been veneered in a darker timber such as mahogany.
  
  Because of its fine grain and resistnce to splitting or chipping it has also been used for treen, turnings, carvings and other small wooden items, such as chess pieces.
• 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.
• George Iii - George III (1738 - 1820) was King of Great Britain and Ireland from 1760 to 1820.
• Movement - The technical name for the workings of a clock or watch, and does not include the dial or case.
• 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.
• Pagoda Top - A shape based loosely on that of a Chinese pagoda, that is, pyramidal with sloped sides and a top cap. However there are many variations on the basic shape from a relatively flat pagoda to a tall pagoda with almost parallel concave sides to a true pagoda shape. As found on a pagoda, the pagoda top is often surmounted by a fancy finial. The pagoda top is most frequently found on the hoods of 18th century long case clocks, and on bracket clocks, and sometimes on Chinese Chippendale style furniture.
• 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.
• 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.
• Bob Pendulum - A bob pendulum consists of a brass or steel rod with a disc shaped metal weight at the end. The most common use of a bob pendulum is in a grandfather clock where it oscillates to keep the time. The length of the rod and the weight of the bob are the key parameters for determining the period of oscillation, and the timekeeping of the clock can be accelerated or slowed by altering the height of the bob.
• Mahogany - Mahogany is a dense, close grained red-coloured timber from the West Indies and Central America. It was first imported into Europe in the the early 18th century and its use continued through the 19th century. It was popular for furniture making because of its strength, the wide boards available, the distinctive grain on some boards, termed flame mahogany and the rich warm colour of the timber when it was polished.. The "flame" was produced where a limb grew out from the trunk of the tree, and this timber was usually sliced into veneers for feature panels on doors, backs and cornices.
  
  Some terms used to describe mahogany relate to the country from which it originally came, such as "Cuban" mahogany, "Honduras" mahogany etc. However unless the wood has been tested the names assigned are more a selling feature, rather than a true indication of the timber's origin.
• 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.

This item has been included into following indexes:

• clocks, mantle & shelf, material or style - mahogany 73