A Louis XV Boulle style mantle clock by Raison & Thomas, Raison & Thomas, formerly Franjus, late 19th century the waisted timber clock with an enamel cartouche dial with Roman numerals, the body with scrolls and floral brass inlay to the scarlet veneer ground set within a cast rocaille mount with an openwork vegetal crest, stamped 'Ancne. Mon. Franjus / Raison & Thomas Successeur' to the brass dial, with key and pendulum. Height 20.28 in., width 10.43 in., depth 5.71 in.
- Cartouche - An ornamental panel in the form of of a shield, oval or rectangular scroll with curling edges. It may be carved into the back of a chair or the top of a sideboard, or present on a piece of silver or jewellery, and contain the initials of the original owner, heraldic symbols, or some other inscription, such as the details of a presentation.
In ceramics the term defines the central area of a vase or similar with a decorative border in one of the shapes above, into which a decorative scene or figures have been painted.
- Boulle - Boulle work is the name given to tortoiseshell and metal inlay using brass and sometimes silver, found on furniture and smaller wooden objects. It originated in Italy but was developed by Frenchman Andre Charles Boulle (1642 - 1732) under Louis XIV.
Boulle was appointed Royal Cainet Maker to Louis XIV and designed furniture and clockcases for the monarch.
In preparation, the tortoiseshell and metal were cut together following a design, using a fine fret saw.
In the application of the Boulle, the carcase of piece of furniture was covered with the tortoiseshell which in turn was inlaid with the matched designs in metal, which in turn was elaborately engraved.
The use of Boulle work furniture continued mainly in France until the 19th century.
- 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.
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