Hooke, Robert

SUBJECT AREA: Horology, Mechanical, pneumatic and hydraulic engineering

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Son of Revd John Hooke, minister of the parish, he was a sickly child who was subject to headaches which prevented protracted study. He devoted his time while alone to making mechanical models including a wooden clock. On the death of his father in October 1648 he was left £100 and went to London, where he became a pupil of Sir Peter Lely and then went to Westminster School under Dr Busby. There he learned the classical languages, some Hebrew and oriental languages while mastering six books of Euclid in one week. In 1653 he entered Christ Church College, Oxford, where he graduated MA in 1663, after studying chemistry and astronomy. In 1662 he was appointed Curator of Experiments to the Royal Society and was elected a Fellow in 1663. In 1665 his appointment was made permanent and he was given apartments in Gresham College, where he lived until his death in 1703. He was an indefatigable experimenter, perhaps best known for the invention of the universal joint named after him. The properties of the atmosphere greatly engaged him and he devised many forms of the barometer. He was the first to apply the spiral spring to the regulation of the balance wheel of the watch in an attempt to measure longitude at sea, but he did not publish his results until after Huygens's reinvention of the device in 1675. Several of his "new watches" were made by Thomas Tompion, one of which was presented to King Charles II. He is said to have invented, among other devices, thirty different ways of flying, the first practical system of telegraphy, an odometer, a hearing aid, an arithmetical machine and a marine barometer. Hooke was a small man, somewhat deformed, with long, lank hair, who went about stooped and moved very quickly. He was of a melancholy and mistrustful disposition, ill-tempered and sharp-tongued. He slept little, often working all night and taking a nap during the day. John Aubrey, his near-contemporary, wrote of Hooke, "He is certainly the greatest Mechanick this day in the World." He is said to have been the first to establish the true principle of the arch. His eyesight failed and he was blind for the last year of his life. He is best known for his Micrographia, or some Physiological Descriptions of Minute Bodies, first published in 1665. After the Great Fire of London, he exhibited a model for the rebuilding of the City. This was not accepted, but it did result in Hooke's appointment as one of two City Surveyors. This proved a lucrative post and through it Hooke amassed a fortune of some thousands of pounds, which was found intact after his death some thirty years later. It had never been opened in the interim period. Among the buildings he designed were the new Bethlehem (Bedlam) Hospital, the College of Physicians and Montague House.

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Hooke, Robert Hooke.

n. Robert Hooke (1635-1703) Engels filosoof en wetenschapper beroemd om zijn studie over elasticiteit

◙ n. רוברט הוק (1635-1703), פילוסוף ומדען אנגלי הידוע בשל מחקריו על הגמישות

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◙ תושימגה לע וירקחמ לשב עודיה ילגנא ןעדמו ףוסוליפ,(3071-5361) קוה טרבור◄

Robert Hooke.

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Adamson, Daniel

Alden, George I.

Archimedes of Syracuse

Ashley, Howard Matravers

Banu Musa ibn Shakir

Bilgram, Hugo

Bodmer, Johann Georg

Bollée, Ernest-Sylvain

Bond, George Meade

Booth, Hubert Cecil

Bramah, Joseph

Brown, Joseph Rogers

Brunel, Isambard Kingdom

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Holtzapffel, Charles

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Roberts, Richard

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Wilson, Robert

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al-Jazari, Ibn al-Razzaz

Arnold, John

Bain, Alexander

Barlow, Edward

Breguet, Abraham-Louis

Burgi, Jost

Cady, Walter Guyton

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Grimthorpe, Edmund Beckett, Baron

Guillaume, Charles-Edouard

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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

Robert Hooke

Robert Hooke

SUBJECT AREA: Horology

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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.

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SUBJECT AREA: Horology

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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.

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SUBJECT AREA: Architecture and building

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Born into a High Church and Royalist family, the young Wren early showed outstanding intellectual ability and at Oxford in 1654 was described as "that miracle of a youth". Educated at Westminster School, he went up to Oxford, where he graduated at the age of 19 and obtained his master's degree two years later. From this time onwards his interests were in science, primarily astronomy but also physics, engineering and meteorology. While still at college he developed theories about and experimentally solved some fifty varied problems. At the age of 25 Wren was appointed to the Chair of Astronomy at Gresham College in London, but he soon returned to Oxford as Savilian Professor of Astronomy there. At the same time he became one of the founder members of the Society of Experimental Philosophy at Oxford, which was awarded its Royal Charter soon after the Restoration of 1660; Wren, together with such men as Isaac Newton, Robert Hooke, John Evelyn and Robert Boyle, then found himself a member of the Royal Society.

Wren's architectural career began with the classical chapel that he built, at the request of his uncle, the Bishop of Ely, for Pembroke College, Cambridge (1663). From this time onwards, until he died at the age of 91, he was fully occupied with a wide and taxing variety of architectural problems which he faced in the execution of all the great building schemes of the day. His scientific background and inventive mind stood him in good stead in solving such difficulties with an often unusual approach and concept. Nowhere was this more apparent than in his rebuilding of fifty-one churches in the City of London after the Great Fire, in the construction of the new St Paul's Cathedral and in the grand layout of the Royal Hospital at Greenwich.

The first instance of Wren's approach to constructional problems was in his building of the Sheldonian Theatre in Oxford (1664–9). He based his design upon that of the Roman Theatre of Marcellus (13–11 BC), which he had studied from drawings in Serlio's book of architecture. Wren's reputation as an architect was greatly enhanced by his solution to the roofing problem here. The original theatre in Rome, like all Roman-theatres, was a circular building open to the sky; this would be unsuitable in the climate of Oxford and Wren wished to cover the English counterpart without using supporting columns, which would have obscured the view of the stage. He solved this difficulty mathematically, with the aid of his colleague Dr Wallis, the Professor of Geometry, by means of a timber-trussed roof supporting a painted ceiling which represented the open sky.

The City of London's churches were rebuilt over a period of nearly fifty years; the first to be completed and reopened was St Mary-at-Hill in 1676, and the last St Michael Cornhill in 1722, when Wren was 89. They had to be rebuilt upon the original medieval sites and they illustrate, perhaps more clearly than any other examples of Wren's work, the fertility of his imagination and his ability to solve the most intractable problems of site, limitation of space and variation in style and material. None of the churches is like any other. Of the varied sites, few are level or possess right-angled corners or parallel sides of equal length, and nearly all were hedged in by other, often larger, buildings. Nowhere is his versatility and inventiveness shown more clearly than in his designs for the steeples. There was no English precedent for a classical steeple, though he did draw upon the Dutch examples of the 1630s, because the London examples had been medieval, therefore Roman Catholic and Gothic, churches. Many of Wren's steeples are, therefore, Gothic steeples in classical dress, but many were of the greatest originality and delicate beauty: for example, St Mary-le-Bow in Cheapside; the "wedding cake" St Bride in Fleet Street; and the temple diminuendo concept of Christ Church in Newgate Street.

In St Paul's Cathedral Wren showed his ingenuity in adapting the incongruous Royal Warrant Design of 1675. Among his gradual and successful amendments were the intriguing upper lighting of his two-storey choir and the supporting of the lantern by a brick cone inserted between the inner and outer dome shells. The layout of the Royal Hospital at Greenwich illustrates Wren's qualities as an overall large-scale planner and designer. His terms of reference insisted upon the incorporation of the earlier existing Queen's House, erected by Inigo Jones, and of John Webb's King Charles II block. The Queen's House, in particular, created a difficult problem as its smaller size rendered it out of scale with the newer structures. Wren's solution was to make it the focal centre of a great vista between the main flanking larger buildings; this was a masterstroke.

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SUBJECT AREA: Horology

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Su Song had a model armillary sphere in his home, which enabled him to study and understand the instrument, but he could not receive an imperial command to make a full-size one before holding an official position. This he attained, and he moved in high official circles in Imperial China; his official appointments included Ambassador, Minister of State and Deputy Imperial Tutor. At the same time he was an outstanding astronomer and calendrical scientist. With the assistance of Han Gonglian, he constructed a water-driven mechanical escapement clock and clocktower in 1088, which he described in detail in his Xin Yi Xian Fa Yao, completed in 1094; this book was noteworthy for illustrations of the armillary sphere and its component parts. The tower included an armillary sphere and celestial globe with clock drive. By applying clockwork to the observational side of the sphere, Su Song anticipated the clockwork drive of the telescope introduced by Robert Hooke six centuries later.

Su Song was also the pharmaceutical naturalist of the Tu Jing Ben Cao of 1061.

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