Georgian Mahogany Long Case Clock by William Lassel (1760s)

• Date Aperture - A date aperture is a cut out section in the face of a watch or clock, displaying the day of the month.
• 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.
• 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.
• 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.
• Subsidiary Dial - On a clock or watch, a subsidiary dial, also called an auxiliary dial, is a dial that is secondary to the main dial and may show seconds, day of the week or month, or strike silent. A subsidiary dial may be within our outside the main dial, and a clock or watch may have several subsidiary dials.
• Georgian - As an English stylistic period, Georgian is usually taken to cover the period from George I (1714) to the Regency of Prince George (1811-20), although the period from 1800 to 1830 is sometimes designated as the Regency period. During the Georgian period the great English cabinetmakers and designers such as Chippendale, Hepplewhite, Adam Sheraton etc., were all active.
  
  Therefore there isn't a single 'Georgian style' as such and to say something is 'Georgian', usually means it was made between 1714 and 1830. This assumes we discount George V and George VI, both being from the 20th century.
  
  The styles popular at the time of each reign were:
  
  George I (1714-1727) saw out the last years of the Baroque period.
  
  George II (1727-1760) reigned during the Rococo period.
  
  George III (1760-1820) saw the last gasp of the Rococo, all of the early Neo-Classic 'Adam style' and most of the later neo-Classic 'Regency style'.
  
  George IV (Prince Regent 1820-1830)encompassed the last of the 'Regency' style.
  
  William IV's reign (1830-1837) was something of a no man's land (stylistically) and he wasn't a 'George' anyway. He covered the last glimmerings of 'Regency' and the start of the 'Victorian' style.
• Calendar Aperture -
  A calendar aperture on a clock refers to a small window on the clock face that displays the day, month or year or all of these. The aperture is usually located on the clock's dial with the date data recorded on a wheel which is designed to rotate to show the correct date information.
  
  
  Some clocks have a manual adjustment for the date, while others are designed to automatically adjust for the date, including for leap years. The calendar aperture is a useful feature found on clocks from the 16th century, and on many types of clocks, including wall clocks, alarm clocks and wristwatches.
• 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.
• 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.

This item has been included into following indexes:

• clocks, grandfather / longcase, period or age - 18th century, mahogany cased 129