Swiss Marble and Brass Perpetual Calendar Mantle Clock

• Movement - The technical name for the workings of a clock or watch, and does not include the dial or case.
• 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.
• Brocot Escapement - The Brocot escapement was invented by the French clockmaker Achille Brocot in 1828. It is a type of escapement, which is a mechanism in a timepiece that controls the movement of the gears and regulates the timekeeping accuracy.
  
  The Brocot escapement is a variation of the detent escapement and it is used in pendulum and spring-driven clocks. It uses a pair of pallets that engage and lock the escape wheel, allowing the clock's power to be transferred to the balance wheel. The escapement also allows the clock's gears to advance in small, precise increments, which helps to improve the clock's timekeeping accuracy. The Brocot escapement was widely used in 19th century for both domestic and public clocks, also it was widely used in marine chronometers.
  
  The Brocot escapement is known for its high accuracy and stability
• 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.
• Foliate - Decorated with leaves or leaf-like forms.
• Bevel / Chamfer - In furniture making, a chamfered corner refers to a technique used to create a smooth, angled edge on the corner of a piece of furniture. This is typically done by cutting away a small portion of the corner at an angle, typically 45 degrees, creating a diagonal edge, rather than a sharp 90-degree angle. This technique can be used on various parts of a piece of furniture such as table legs, drawer fronts, or door frames. Chamfering can add visual interest to a piece and can help to soften the overall look of a piece of furniture. It is often used in conjunction with other techniques, such as rounding edges or using contrasting wood species to create a more elegant, sophisticated look. Chamfering is a simple way to add a touch of elegance to a piece of furniture and it is a common technique used by furniture makers.
• Matted - For decorative purposes the centre exposed brass area of a dial clock was often matted. this practice, dating from the second half of the 17th century was produced by hammering the brass with a single or multi-pointed punch, by rolling the brass or by etching the brass with acid.
  
  The process creates a fine granulated surface in which the light is refracted in different directions and so was more pleasing to the eye than the flat brass surface.

This item has been included into following indexes:

• clocks, mantle & shelf, material or style - gilt metal / ormolu 547