-
1 Huygens, Christiaan
SUBJECT AREA: Horology[br]b. 14 April 1629 The Hague, the Netherlandsd. 8 June 1695 The Hague, the Netherlands[br]Dutch scientist who was responsible for two of the greatest advances in horology: the successful application of both the pendulum to the clock and the balance spring to the watch.[br]Huygens was born into a cultured and privileged class. His father, Constantijn, was a poet and statesman who had wide interests. Constantijn exerted a strong influence on his son, who was educated at home until he reached the age of 16. Christiaan studied law and mathematics at Ley den University from 1645 to 1647, and continued his studies at the Collegium Arausiacum in Breda until 1649. He then lived at The Hague, where he had the means to devote his time entirely to study. In 1666 he became a Member of the Académie des Sciences in Paris and settled there until his return to The Hague in 1681. He also had a close relationship with the Royal Society and visited London on three occasions, meeting Newton on his last visit in 1689. Huygens had a wide range of interests and made significant contributions in mathematics, astronomy, optics and mechanics. He also made technical advances in optical instruments and horology.Despite the efforts of Burgi there had been no significant improvement in the performance of ordinary clocks and watches from their inception to Huygens's time, as they were controlled by foliots or balances which had no natural period of oscillation. The pendulum appeared to offer a means of improvement as it had a natural period of oscillation that was almost independent of amplitude. Galileo Galilei had already pioneered the use of a freely suspended pendulum for timing events, but it was by no means obvious how it could be kept swinging and used to control a clock. Towards the end of his life Galileo described such a. mechanism to his son Vincenzio, who constructed a model after his father's death, although it was not completed when he himself died in 1642. This model appears to have been copied in Italy, but it had little influence on horology, partly because of the circumstances in which it was produced and possibly also because it differed radically from clocks of that period. The crucial event occurred on Christmas Day 1656 when Huygens, quite independently, succeeded in adapting an existing spring-driven table clock so that it was not only controlled by a pendulum but also kept it swinging. In the following year he was granted a privilege or patent for this clock, and several were made by the clockmaker Salomon Coster of The Hague. The use of the pendulum produced a dramatic improvement in timekeeping, reducing the daily error from minutes to seconds, but Huygens was aware that the pendulum was not truly isochronous. This error was magnified by the use of the existing verge escapement, which made the pendulum swing through a large arc. He overcame this defect very elegantly by fitting cheeks at the pendulum suspension point, progressively reducing the effective length of the pendulum as the amplitude increased. Initially the cheeks were shaped empirically, but he was later able to show that they should have a cycloidal shape. The cheeks were not adopted universally because they introduced other defects, and the problem was eventually solved more prosaically by way of new escapements which reduced the swing of the pendulum. Huygens's clocks had another innovatory feature: maintaining power, which kept the clock going while it was being wound.Pendulums could not be used for portable timepieces, which continued to use balances despite their deficiencies. Robert Hooke was probably the first to apply a spring to the balance, but his efforts were not successful. From his work on the pendulum Huygens was well aware of the conditions necessary for isochronism in a vibrating system, and in January 1675, with a flash of inspiration, he realized that this could be achieved by controlling the oscillations of the balance with a spiral spring, an arrangement that is still used in mechanical watches. The first model was made for Huygens in Paris by the clockmaker Isaac Thuret, who attempted to appropriate the invention and patent it himself. Huygens had for many years been trying unsuccessfully to adapt the pendulum clock for use at sea (in order to determine longitude), and he hoped that a balance-spring timekeeper might be better suited for this purpose. However, he was disillusioned as its timekeeping proved to be much more susceptible to changes in temperature than that of the pendulum clock.[br]Principal Honours and DistinctionsFRS 1663. Member of the Académie Royale des Sciences 1666.BibliographyFor his complete works, see Oeuvres complètes de Christian Huygens, 1888–1950, 22 vols, The Hague.1658, Horologium, The Hague; repub., 1970, trans. E.L.Edwardes, AntiquarianHorology 7:35–55 (describes the pendulum clock).1673, Horologium Oscillatorium, Paris; repub., 1986, The Pendulum Clock or Demonstrations Concerning the Motion ofPendula as Applied to Clocks, trans.R.J.Blackwell, Ames.The balance spring watch was first described in Journal des Sçavans 25 February 1675, and translated in Philosophical Transactions of the Royal Society (1675) 4:272–3.Further ReadingH.J.M.Bos, 1972, Dictionary of Scientific Biography, ed. C.C.Gillispie, Vol. 6, New York, pp. 597–613 (for a fuller account of his life and scientific work, but note the incorrect date of his death).R.Plomp, 1979, Spring-Driven Dutch Pendulum Clocks, 1657–1710, Schiedam (describes Huygens's application of the pendulum to the clock).S.A.Bedini, 1991, The Pulse of Time, Florence (describes Galileo's contribution of the pendulum to the clock).J.H.Leopold, 1982, "L"Invention par Christiaan Huygens du ressort spiral réglant pour les montres', Huygens et la France, Paris, pp. 154–7 (describes the application of the balance spring to the watch).A.R.Hall, 1978, "Horology and criticism", Studia Copernica 16:261–81 (discusses Hooke's contribution).DV -
2 Tompion, Thomas
SUBJECT AREA: Horology[br]baptized 25 July 1639 Ickwell Green, Englandd. 20 November 1713 London, England[br]English clock-and watchmaker of great skill and ingenuity who laid the foundations of his country's pre-eminence in that field.[br]Little is known about Tompion's early life except that he was born into a family of blacksmiths. When he was admitted into the Clockmakers' Company in 1671 he was described as a "Great Clockmaker", which meant a maker of turret clocks, and as these clocks were made of wrought iron they would have required blacksmithing skills. Despite this background, he also rapidly established his reputation as a watchmaker. In 1674 he moved to premises in Water Lane at the sign of "The Dial and Three Crowns", where his business prospered and he remained for the rest of his life. Assisted by journeymen and up to eleven apprentices at any one time, the output from his workshop was prodigious, amounting to over 5,000 watches and 600 clocks. In his lifetime he was famous for his watches, as these figures suggest, but although they are of high quality they do not differ markedly from those produced by other London watchmakers of that period. He is now known more for the limited number of elaborate clocks that he produced, such as the equation clock and the spring-driven clock of a year's duration, which he made for William III. Around 1711 he took into partnership his nephew by marriage, George Graham, who carried on the business after his death.Although Tompion does not seem to have been particularly innovative, he lived at a time when great advances were being made in horology, which his consummate skill as a craftsman enabled him to exploit. In this he was greatly assisted by his association with Robert Hooke, for whom Tompion constructed a watch with a balance spring in 1675; at that time Hooke was trying to establish his priority over Huygens for this invention. Although this particular watch was not successful, it made Tompion aware of the potential of the balance spring and he became the first person in England to apply Huygens's spiral spring to the balance of a watch. Although Thuret had constructed such a watch somewhat earlier in France, the superior quality of Tompion's wheel work, assisted by Hooke's wheel-cutting engine, enabled him to dominate the market. The anchor escapement (which reduced the amplitude of the pendulum's swing) was first applied to clocks around this time and produced further improvements in accuracy which Tompion and other makers were able to utilize. However, the anchor escapement, like the verge escapement, produced recoil (the clock was momentarily driven in reverse). Tompion was involved in attempts to overcome this defect with the introduction of the dead-beat escapement for clocks and the horizontal escapement for watches. Neither was successful, but they were both perfected later by George Graham.[br]Principal Honours and DistinctionsMaster of the Clockmakers' Company 1703.Bibliography1695, with William Houghton and Edward Barlow, British patent no. 344 (for a horizontal escapement).Further ReadingR.W.Symonds, 1951, Thomas Tompion, His Life and Work, London (a comprehensive but now slightly dated account).H.W.Robinson and W.Adams (eds), 1935, The Diary of Robert Hooke (contains many references to Tompion).D.Howse, 1970, The Tompion clocks at Greenwich and the dead-beat escapement', Antiquarian Horology 7:18–34, 114–33.DV
См. также в других словарях:
Balance wheel — in a cheap 1950s alarm clock, the Apollo, by Lux Mfg. Co. showing the balance spring (1) and regulator (2) … Wikipedia
The Young and the Restless minor characters — The following are characters from the American soap opera The Young and the Restless who are notable for their actions or relationships, but who do not warrant their own articles. Contents 1 Current Characters 1.1 Genevieve … Wikipedia
The Gunpowder Plot — The Gunpowder Plot † Catholic Encyclopedia ► The Gunpowder Plot (Oath taken May, 1604, plot discovered November, 1605). Robert Catesby, the originator of the Powder Plot, owned estates at Lapworth and Ashby St. Legers. His ancient and … Catholic encyclopedia
The Natural Economic Order — is the most famous book of Silvio Gesell. PUBLISHED REFERENCES TO GESELL S THEORY John Maynard Keynes: General Theory of Employment, Interest and Money (1936): Gesell s main book is written in cool, scientific language; though it is suffused… … Wikipedia
Mechanical watch — The movement of a Russian watch A mechanical watch is a watch that uses a mechanical mechanism to measure the passage of time, as opposed to modern quartz watches which function electronically. It is driven by a spring (called a mainspring) which … Wikipedia
The Rolling Stones — Rolling Stones redirects here. For other uses, see Rolling Stones (disambiguation). The Rolling Stones Mick Jagger, Keith Richards, Ronnie Wood, Charlie Watts … Wikipedia
The Disasters of War — Plate 3: Lo mismo (The same). A man about to cut off the head of a soldier with an axe.[1] … Wikipedia
History of the Luftwaffe 1933 - 1945 — The German Luftwaffe was one of the strongest, doctrinally advanced, and battle experienced air forces in the world when World War II started in Europe in September 1939. Officially unveiled in 1935, in violation of the Treaty of Versailles, its… … Wikipedia
The Long and Winding Road — Single infobox Name = The Long and Winding Road Artist = The Beatles from Album = Let It Be B side = For You Blue Released = 11 May 1970 (USA) Format = vinyl record (7 ) Recorded = 26 January 1969 Genre = Ballad Length = 3:37 (original album)… … Wikipedia
History of the Song Dynasty — The Song Dynasty (Chinese: ; pinyin: Sòng cháo; 960 1279) of China was a ruling dynasty that controlled China proper and southern China from the middle of the 10th century into the last quarter of the 13th century. The Song Dynasty is considered… … Wikipedia
HISTORICAL SURVEY: THE STATE AND ITS ANTECEDENTS (1880–2006) — Introduction It took the new Jewish nation about 70 years to emerge as the State of Israel. The immediate stimulus that initiated the modern return to Zion was the disappointment, in the last quarter of the 19th century, of the expectation that… … Encyclopedia of Judaism
