18th Century English Japanned Longcase Clock by Charles Pingstone

• Date Aperture - A date aperture is a cut out section in the face of a watch or clock, displaying the day of the month.
• 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.
• Spandrel - An architectural term that in horology refers to the triangular ornamental decoration in the corners of of the dial plate. The spandrels are usually of cast brass and may be additonally chased and engraved. On painted dial clocks the spandrels are also usually painted.
• Japanning - Japanning is the early eighteenth century technique used by European craftsmen to imitate the oriental style lacquer work that became popular in England, France, the Netherlands, and Spain in the 17th century.
  
  The lacquer used was based on the lac beetle dissolved in alcohol (as used in French polish) and differed from the Chinese lacquer which was based on tree sap.
  
  Each layer of the lacquer was allowed to dry and then sanded down. It was applied over cream, yellow, green, red, or black grounds. Japanning using gold leaf was also widely used with lacquer work. The technique can be found on bureaux, cabinets, chests, longcase clocks, and chairs.
• Lenticle in a Long Case Clock - A lenticle in a long case clock (also known as grandfather clocks) is a convex lens used usually located as a small circular window on the front door of the clock case, just below the clock face. The lenticle enables the pendulum to be viewed without needing to open the door in the trunk. The lens is convex, meaning that it bulges outward, and is made of glass
• Chapter Ring - A separate metal plate on the face of a clock, on which the numerals for the hours and sometimes parts of the hours, are displayed, usually wheel shaped and sitting on top of the dial plate. The chapter ring is often a feature of the clock and can be silvered or enamelled to stand as a contrast to its background. The hours are usually shown in Roman numerals, although in the late 19th and earlt 20th century, Arabic numerals became fashionable.
• Foliate - Decorated with leaves or leaf-like forms.
• 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.
• Polychrome - Made or finished in many colours. For furniture, it is used to indicated a painted finish.
• Hood - In longcase clocks, the hood is the wooden case that surrounds the works and dial, and includes the glass front, which is usually hinged, so the door can be opened to wind the clock or adjust the time. In 18th and 19th century longcase clocks the hood usually slides forward for removal, allowing access to the works.

This item has been included into following indexes:

• clocks, grandfather / longcase, period or age - 18th century, other 107
• clocks, grandfather / longcase, type - Chinoiserie and lacquer 31