19th Century French Slate Clock with Mercury Pendulum

• 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.
• 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.

This item has been included into following indexes:

• clocks, material or decoration
  • marble or slate, black 345
  • slate 347