Breguet, Abraham-Louis

SUBJECT AREA: Horology

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When Breguet was 11 years old his father died and his mother married a Swiss watchmaker who had Paris connections. His stepfather introduced him to horology and this led to an apprenticeship in Paris, during which he also attended evening classes in mathematics at the Collège Mazarin. In 1775 he married and set up a workshop in Paris, initially in collaboration with Xavier Gide. There he established a reputation among the aristocracy for elegant and innovative timepieces which included a perpétuelle, or self-winding watch, which he developed from the ideas of Perrelet. He also enjoyed the patronage of Marie Antoinette and Louis XVI. During the French Revolution his life was in danger and in 1793 he fled to Neuchâtel. The two years he spent there comprised what was intellectually one of his most productive periods and provided many of the ideas that he was able to exploit after he had returned to Paris in 1795. By the time of his death he had become the most prestigious watchmaker in Europe: he supplied timepieces to Napoleon and, after the fall of the Empire, to Louis XVIII, as well as to most of the crowned heads of Europe.

Breguet divided his contributions to horology into three categories: improvements in appearance and functionality; improvements in durability; and improvements in timekeeping. His pendule sympathique was in the first category and consisted of a clock which during the night set a watch to time, regulated it and wound it. His parachute, a spring-loaded bearing, made a significant contribution to the durability of a watch by preventing damage to its movement if it was dropped. Among the many improvements that Breguet made to timekeeping, two important ones were the introduction of the overcoil balance spring and the tourbillon. By bending the outside end of the balance spring over the top of the coils Breguet was able to make the oscillations of the balance isochronous, thus achieving for the flat spring what Arnold had already accomplished for the cylindrical balance spring. The timekeeping of a balance is also dependent on its position, and the tourbillon was an attempt to average-out positional errors by placing the balance wheel and the escapement in a cage that rotated once every minute. This principle was revived in a simplified form in the karussel at the end of the nineteenth century.

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See also: INDEX BY SUBJECT AREA

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al-Jazari, Ibn al-Razzaz

Arnold, John

Bain, Alexander

Barlow, Edward

Breguet, Abraham-Louis

Burgi, Jost

Cady, Walter Guyton

Ctesibius of Alexandria

Dondi, Giovanni

Essen, Louis

Graham, George

Grimthorpe, Edmund Beckett, Baron

Guillaume, Charles-Edouard

Harrison, John

Harwood, John

Hetzel, Max

Hipp, Matthäus

Hooke, Robert

Huygens, Christiaan

Leonardo da Vinci

Le Roy, Pierre

Leschot, Georges Auguste

Lioret, Henri Jules

Marrison, Warren Alvin

Mudge, Thomas

Richard of Wallingford, Abbot

Riefler, Sigmund

Shortt, William Hamilton

Sinclair, Sir Clive Maries

Su Song

Tompion, Thomas

Warren, Henry Ellis

Yi-Xing

Zhang Sixun

SUBJECT AREA: Horology

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Graham's father died soon after his birth, so he was raised by his brother. In 1688 he was apprenticed to the London clockmaker Henry Aske, and in 1695 he gained his freedom. He was employed as a journeyman by Tompion in 1696 and later married his niece. In 1711 he formed a partnership with Tompion and effectively ran the business in Tompion's declining years; he took over the business after Tompion died in 1713. In addition to his horological interests he also made scientific instruments, specializing in those for astronomical use. As a person, he was well respected and appears to have lived up to the epithet "Honest George Graham". He befriended John Harrison when he first went to London and lent him money to further his researches at a time when they might have conflicted with his own interests.

The two common forms of escapement in use in Graham's time, the anchor escapement for clocks and the verge escapement for watches, shared the same weakness: they interfered severely with the free oscillation of the pendulum and the balance, and thus adversely affected the timekeeping. Tompion's two frictional rest escapements, the dead-beat for clocks and the horizontal for watches, had provided a partial solution by eliminating recoil (the momentary reversal of the motion of the timepiece), but they had not been successful in practice. Around 1720 Graham produced his own much improved version of the dead-beat escapement which became a standard feature of regulator clocks, at least in Britain, until its supremacy was challenged at the end of the nineteenth century by the superior accuracy of the Riefler clock. Another feature of the regulator clock owed to Graham was the mercury compensation pendulum, which he invented in 1722 and published four years later. The bob of this pendulum contained mercury, the surface of which rose or fell with changes in temperature, compensating for the concomitant variation in the length of the pendulum rod. Graham devised his mercury pendulum after he had failed to achieve compensation by means of the difference in expansion between various metals. He then turned his attention to improving Tompion's horizontal escapement, and by 1725 the cylinder escapement existed in what was virtually its final form. From the following year he fitted this escapement to all his watches, and it was also used extensively by London makers for their precision watches. It proved to be somewhat lacking in durability, but this problem was overcome later in the century by using a ruby cylinder, notably by Abraham Louis Breguet. It was revived, in a cheaper form, by the Swiss and the French in the nineteenth century and was produced in vast quantities.

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See also: Barlow, Edward; Guillaume, Charles-Edouard

SUBJECT AREA: Horology

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John Harwood served an apprenticeship as a watch repairer in Bolton, and after service in the First World War he obtained a post with a firm of jewellers in Douglas, Isle of Man. He became interested in the self-winding wrist watch, not because of the convenience of not having to wind it, but because of its potential to keep the mainspring fully wound and to exclude dust and moisture from the watch movement. His experience at the bench had taught him that these were the most common factors to affect adversely the reliability of watches. Completely unaware of previous work in this area, in 1922 he started experimenting and two years later he had produced a serviceable model for which he was granted a patent in 1924. The watch operated on the pedometer principle, the mainspring being wound by a pivoted weight that oscillated in the watch case as a result of the motion of the arm. The hands of his watch were set by rotating the bezel surrounding the dial, dispensing with the usual winding/hand-setting stem which allowed dust and moisture to enter the watch case. He took the watch to Switzerland, but he was unable to persuade the watchmaking firms to produce it until he had secured independent finance to cover the cost of tooling. The Harwood Self-Winding Watch Company Ltd was set up in 1928 to market the watches, but although several thousand were produced the company became a victim of the slump and closed down in 1932. The first practical self-winding watch also operated on the pedometer principle and is attributed to Abraham-Louis Perrellet (1770). The method was refined by Breguet in France and by Recordon, who patented the device in England, but it proved troublesome and went out of fashion. There was a brief revival of interest in self-winding watches towards the end of the nineteenth century, but they never achieved great popularity until after the Second World War, when they used either self-winding mechanisms similar to that devised by Harwood or weights which rotated in the case.

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