Biografia de robert hooke court

Consultado el 23 de enero de A Short History of Astronomy. London: John Murray. Isaac Newton New York: Macmillan. A Portrait of Isaac Newton. Cambridge, Massachusetts: Harvard University Press. Isaac Newton. New York: Charles Schribner's Sons. New York: Chanticleer Press. Robinson, H. The Diary of Robert Hooke, M. Robert Hooke. London: William Heinemann Ltd.

Alianza Editorial. Archivado desde el original el 28 de junio de Archivado desde el original el 22 de abril de Greenwood Publishing Group. Ashley Isis 33 : See also 3 July issue of Time page In Marchhe published his findings and from them, the Italian astronomer Giovanni Cassini calculated the rotation period of Jupiter to be nine hours and fifty-five minutes.

One of the most-challenging problems Hooke investigated was the measurement of the distance from Earth to a star other than the Sun. Hooke selected the star Gamma Draconis and chose the method of parallax determination. Inafter several months of observing, Hooke believed the desired result had been achieved. It is now known his equipment was far too imprecise to obtain an accurate measurement.

Hooke's Micrographia contains illustrations of the Pleiades star cluster and lunar biografia de roberts hooke court. He conducted experiments to investigate the formation of these craters and concluded their existence meant the Moon must have its own gravity, a radical departure from the contemporaneous Aristotelian celestial model. To achieve these discoveries, Hooke needed better instruments than those that were available at the time.

Accordingly, he invented three new mechanisms: the Hooke jointa sophisticated universal joint that allowed his instruments to smoothly follow the apparent motion of the observed body; the first clockwork drive to automate the process; and a micrometer screw that allowed him to achieve a precision of ten seconds of arc. InHooke discovered the law of elasticity that bears his name and describes the linear variation of tension with extension in an elastic spring.

Hooke first described this discovery in an anagram "ceiiinosssttuv", whose solution he published in as Ut tensio, sic vis "As the extension, so the force". A bitter dispute between Hooke and Christiaan Huygens on the priority of this invention was to continue for centuries after the death of both but a note dated 23 June in the journals of the Royal Society, [ ] describing a demonstration of a balance-controlled watch before the Royal Society, may support Hooke's claim to priority for the idea.

Nevertheless, it is Huygens who is credited with building the first watch to use a balance spring. Hooke's announcement of his law of elasticity using an anagram was a method scientists, such as Hooke, Huygens and Galileosometimes used to establish priority for a discovery without revealing details. While many of Hooke's contemporaries, such as Isaac Newton, believed in aether as a medium for transmitting attraction and repulsion between separated celestial bodies, [ ] [ ] Hooke argued for an attracting principle of gravitation in Micrographia In a communication to the Royal Society in[ ] he wrote:.

I will explain a system of the world very different from any yet received. It is founded on the following positions. That all the heavenly bodies have not only a gravitation of their parts to their own proper centre, but that they also mutually attract each other within their spheres of action. That all bodies having a simple motion, will continue to move in a straight line, unless continually deflected from it by some extraneous force, causing them to describe a circle, an ellipse, or some other curve.

That this attraction is so much the greater as the bodies are nearer. As to the proportion in which those forces diminish by an increase of distance, I own I have not discovered it. Hooke's Gresham lecture, An Attempt to Prove the Motion of the Earth by Observations publishedsaid gravitation applies to "all celestial bodies" [ ] and restated these three propositions.

Hooke's statements up to make no mention, however, that an inverse square law applies or might apply to these attractions. His model of gravitation was also not yet universal, though it approached universality more closely than previous hypotheses. In NovemberHooke initiated a notable exchange of letters with Newton that was published in Hooke asked Newton's opinions about various matters.

Among other items, Hooke mentioned "compounding the celestial motions of the planets of a direct motion by the tangent and an attractive motion towards the central body"; his "hypothesis of the lawes or causes of springinesse"; a new hypothesis from Paris about planetary motions, which he described at length; efforts to carry out or improve national surveys; and the difference of latitude between London and Cambridge.

Newton's reply offered "a fansy of my own" about a terrestrial experiment rather than a proposal about celestial motions that might detect the Earth's motion; the experiment would use a body suspended in air and then dropped. Hooke wanted to discern how Newton thought the falling body could experimentally reveal the Earth's motion by its direction of deviation from the vertical but Hooke went on hypothetically to consider how its motion could continue if the solid Earth had not been in the way, on a spiral path to the centre.

Hooke disagreed with Newton's idea of the body's continuing motion. A further short correspondence developed; towards the end of it, writing on 6 January to Newton, Hooke communicated his "supposition Inwhen the first book of Newton's Principia was presented to the Royal Society, Hooke said he had given Newton the "notion" of "the rule of the decrease of Gravity, being reciprocally as the squares of the distances from the Center".

At the biografia de robert hooke court time, according to Edmond Halley 's contemporaneous report, Hooke agreed "the Demonstration of the Curves generated thereby" was wholly Newton's. According to a assessment of the early history of the inverse square law: "by the late s, the assumption of an 'inverse proportion between gravity and the square of distance' was rather common and had been advanced by a number of different people for different reasons".

These, he said, enabled observations to be relied upon as evidence of its accuracy while according to Newton, Hooke, without mathematical demonstrations and evidence in favour of the supposition, could only guess it was approximately valid "at great distances from the centre". Newton did accept and acknowledge, in all editions of the PrincipiaHooke and others had separately appreciated the inverse square law in the solar system.

Newton wrote:. Yet am I not beholden to him for any light into that business Whilst Newton was primarily a pioneer in mathematical analysis and its applications, and optical experimentation, Hooke was a creative experimenter of such great range who left some of his ideas, such as those about gravitation, undeveloped. Indecades after the deaths of both Newton and Hooke, Alexis Clairautmathematical astronomer eminent in his own right in the field of gravitational studies, reviewed Hooke's published work on gravitation.

According to Stephen Peter RigaudClairaut wrote: "The example of Hooke and that of Kepler [serves] to show what a distance there is between a truth that is glimpsed and a truth that is demonstrated". Bernard Cohen said: "Hooke's claim to the inverse-square law has masked Newton's far more fundamental debt to him, the analysis of curvilinear orbital motion.

In asking for too much credit, Hooke effectively denied to himself the credit due him for a seminal idea". Hooke made important contributions to the science of timekeeping and was intimately involved in the advances of his time; these included refinement of the pendulum as a better regulator for clocks, increased precision of clock mechanisms and the use of the balance spring to improve the timekeeping of watches.

Galileo had observed the regularity of a pendulum and Huygens first incorporated it in a clock; [ ] inHooke demonstrated his new biografia de robert hooke court to keep a pendulum swinging regularly in unsteady conditions. Hooke announced he conceived a way to build a marine chronometer to determine longitude. In the process, Hooke demonstrated a pocket-watch of his own devising that was fitted with a coil spring attached to the arbour of the balance.

Hooke's refusal to accept an escape clause in the proposed exclusive contract for the use of this idea resulted in its abandonment. Hooke developed the principle of the balance spring independently of Huygens and at least five years beforehand. In andHooke made his microscopic, and some astronomic, observations, which he collated in Micrographia in His book, which describes observations with microscopes and telescopes, as well as original work in biology, contains the earliest-recorded observation of a microorganism, the microfungus Mucor.

Micrographia also contains Hooke's, or perhaps Boyle's and Hooke's, ideas on combustion. Hooke's experiments led him to conclude combustion involves a component of air, a statement with which modern scientists would agree but that was not understood widely, if at all, in the seventeenth century. He also concluded respiration and combustion involve a specific and limited component of air.

Hooke's Microscopicall Observations, the most ingenious book that ever I read in my life". One of the observations in Micrographia is of fossil woodthe microscopic structure of which Hooke compared to that of ordinary wood. This led him to conclude that fossilised objects like petrified wood and fossil shells such as ammonites were the remains of living things that had been soaked in mineral-laden petrifying water.

Hooke's scientific model of human memory was one of the first of its kind. In a lecture to the Royal Society, Hooke proposed a mechanical analogue model of human memory that bore little resemblance to the mainly philosophical models of earlier writers. On 8 JulyHooke observed the nodal patterns associated with the modes of vibration of glass plates.

He ran a bow along the edge of a flour-covered glass plate and saw the nodal patterns emerge. Wren and Hooke were both keen astronomers. The Monument to the Great Fire of London was designed to serve a scientific function as a zenith telescope for astronomical observation, though traffic vibration made it unusable for this purpose. He also collaborated with Wren on the design of St Paul's Cathedral ; Hooke determined the ideal shape of an arch is an inverted catenary and thence that a circular series of such arches makes an ideal shape for the cathedral's dome.

In the reconstruction after the Great Fire, Hooke proposed redesigning London's streets on a grid pattern with wide boulevards and arteries, [ ] a pattern that was later used in Haussmann's renovation of Paris and in many American cities, for which Wren and others also submitted proposals. The King decided both the prospective cost of building and compensation, and the need to quickly restore trade and population meant the city would be rebuilt on the original property lines.

He was closely involved with the drafting of an Act of Common Council Aprilwhich set out the process by which the original foundations would be formally recognised and certificated. Hooke also had to measure and certify land that would be compulsorily purchased for the planned road widening so compensation could be paid. No authenticated portrait of Robert Hooke exists, a situation that has sometimes been attributed to the heated conflicts between Hooke and Isaac Newton, although Hooke's biographer Allan Chapman rejects as a myth claims Newton or his acolytes deliberately destroyed Hooke's portrait.

When the Royal Society moved to new premises inHooke's was the only portrait that went missing [ ] and remains so. According to Hooke's diary, he sat for a portrait by renowned artist Mary Bealeso it is possible such a portrait did at some time exist. Two contemporaneous, written descriptions of Hooke's appearance have survived; his close friend John Aubrey described him in middle age and at the height of his creative powers:.

He is but of midling stature, something crooked, pale faced, and his face but little below, but his head is lardge, his eie full and popping, and not quick; a grey eie. He haz a delicate head of haire, browne, and of an excellent moist curle. He is and ever was temperate and moderate in dyet, etc. As to his Person he was but despicable, being very crooked, tho' I have heard from himself, and others, that he was strait till about 16 Years of Age when he first grew awry, by frequent practising, with a Turn-Lath He was always very pale and lean, and laterly nothing but Skin and Bone, with a Meagre Aspect, his Eyes grey and full, with a sharp ingenious Look whilst younger; his nose but thin, of a moderate height and length; his Mouth meanly wide, and upper lip thin; his Chin sharp, and Forehead large; his Head of a middle size.

He wore his own Hair of a dark Brown colour, very long and hanging neglected over his Face uncut and lank On 3 JulyTime magazine published a portrait, supposedly of Hooke, but when Ashley Montagu traced the source, it was found to lack a verifiable connection to Hooke. Montagu found the two contemporaneous written descriptions of Hooke's appearance agree with one another but that neither matches the portrait in Time.

Inhistorian Lisa Jardine conjectured that a recently discovered portrait was of Hooke, [ ] but this proposal was disproved by William B. Inthe amateur painter Rita Greer embarked on a project to memorialise Hooke and produce credible images of him, both painted and drawn, she believes match Aubrey's and Waller's the descriptions of him.

Greer's images of Hooke, which are free to use under the Free Art Licensehave been used for television programmes in the UK and the US, in books, magazines and for public relations. The figure points to a drawing of elliptical motion that appears to match an unpublished manuscript created by him. The painting also includes an orrery depicting the same principle.

The church was renovated under one of Hooke's architectural commissions, which Beale would have known from her extensive body of work for the Lowther family. Contents move to sidebar hide.

Biografia de robert hooke court

Article Talk. Read View source View history. Tools Tools. Download as PDF Printable version. In other projects. Wikimedia Commons Wikiquote Wikisource Wikidata item. He also had a barrel of Flanstead's ale and Tillotson's ale. There are a few instances when he recorded that he had been drunk He was a gregarious person, who liked to meet people, particularly those who had travelled abroad As Hooke grew older he became more cynical and would shut himself away from company.

The papers which he wrote in the last few years of his life are filled with bitter comments. In February Hooke gave two lectures to the Royal Society which are reproduced in part in [ 26 ]. At this time, according to Waller [ 11 ]Hooke was Hooke shows how bitter he feels in these lectures. For example, in the second lecture he said:- [ Huygens ' Preface ] is concerning those properties of gravity which I myself first discovered and showed to this Society and years since, which of late Mr Newton has done me the favour to print and publish as his own inventions.

And particularly that of the oval figure of the Earth which was read by me to this Society about 27 years since upon the occasion of the carrying the pendulum clocks to sea and at two other times since, though I have had the ill fortune not to be heard, and I conceive there are some biografia de robert hooke court that may very well remember and do know that Mr Newton did not send up that addition to his book till some weeks after I had read and showed the experiments and demonstration thereof in this place and had answered the reproachful letter of Dr Wallis from Oxford.

However I am well pleased to find that the truth will at length prevail when men have laid aside their prepossessions and prejudices. And as that hath found approvers in the world and those thinking men too, so I doubt not but that divers other discoveries which I have here first made when they come to be well considered and examined be found not so unreasonable or extravagant as some would willingly make them.

After his death Waller edited [ 11 ]a major publication of previously unpublished works by Hooke. A large portion of this work is devoted to Hooke's lectures on earthquakes. Over a period of thirty years he made major contributions to geology, particularly his investigation of fossil remains which convinced him that major changes had occurred in the Earth's surface which had lifted fossilised shells of marine animals to high points in mountain ranges.

Hooke has been described as a A possible portrait recently found at the Royal Society has now been established as being of someone else. References show. Biography in Encyclopaedia Britannica. Pioneers in mathematical analysis and catastrophe theory from evolvents to quasicrystals Basel, F F Centore, Robert Hooke's contributions to mechanics : a study in seventeenth century natural philosophy The Hague, W Derham ed.

M Espinasse, Robert Hooke London, M Hunter and S Schaffer eds. R Waller ed. London A- XL Mem. H Erlichson, Newton and Hooke on centripetal force motion, Centaurus 35 146 - O Gal, Producing knowledge in the workshop : Hooke's 'inflection' from optics to planetary motion, Stud. London 8 1 - 51- London 44 113 - M Hesse, Hooke's philosophical algebra, Isis 5767 - M Hesse, Hooke's vibration theory and the isochrony of springs, Isis 57- R Lehti, Newton's road to classical dynamics.

Robert Hooke's influence on Newton's dynamics FinnishArkhimedes 39 118 - J Lohne, Hooke versus Newton : An analysis of the documents in the case on free fall and planetary motion, Centaurus 76 - As for his salary as lecturer, Cutler made a career of bestowing in public benefactions that he refused in private to fulfill, and Hooke had to take him to court to obtain his due.

Almost on the morrow of the disaster he came forward with a plan to rearrange the city wholly by laying it out on a rectangular grid. The plan won the approval of the city fathers; although it never approached implementation, it did promote his nomination as one of three surveyors appointed by the city to reestablish property lines and to supervise the rebuilding.

As surveyor, Hooke was thrown into daily commerce with Sir Christopher Wrenone of the men appointed by the royal government to the same task of rebuilding. Wren and Hooke dominated and guided the work, and cemented a friendship that lasted throughout their lives. To Hooke the position of surveyor was a financial boon, more than compensating for the uncertainty of his other income.

It also provided an outlet for his artistic talents. A number of prominent buildings, such as the Royal College of Physicians, Bedlam Hospital, and the Monument, were his work. His career as an architect adds another dimension to his achievement. The ten years following the fire constituted a period of hectic activity. The very time when the demands of his surveyorship were at their peak was also a period of productive scientific work.

Inthe year before the fire, he had published Micrographiathe most important book that he produced. Vindica me Deus, people almost pointed. It remains one of the masterpieces of seventeenth-century science. Above all, the book suggested what the microscope could do for the biological sciences. In the animal realm, he inaugurated the study of insect anatomy.

His horrendous portraits of the flea and the louse, a frightening eighteen inches long, are hardly less startling today than they must have been in the seventeenth century. He examined and understood the multiple eye of the fly, and he portrayed such diverse structures as feathers and apian stings. Frequent reproduction of the Micrographia testifies to the unfading fascination it continues to exercise.

Hooke also used the book as a vehicle to expound his own scientific theories. A work devoted to the microscope may be excused for proposing a theory of light, however tenuously connected to microscopical observations as such. An adherent of the mechanical philosophy of nature, Hooke held light to be mechanical as well: pulses of motion transmitted through a material medium.

Neither in the Micrographia nor in his later lectures on light, delivered before the Royal Society, did he examine the theory at any great depth; but its mere proposal suffices to enroll him among the forebears of the wave theory of light. Moreover, the specific cause that shaped the theory was a set of observations destined to play an important role in the history of optics.

Initially with mica, and then with soap bubbles, layers of air between sheets of glass, and a host of analogous instances, Hooke examined phenomena of colors in thin, transparent films. He recognized that the colors are periodic, with the spectrum repeating itself as the thickness of the film increases. His theory of light intended specifically to account for such phenomena.

Except in the most general terms, the theory has. Yet his observations of thin films did exert an extensive influence. Both Huygens and Newton saw that the thickness of the films could be calculated from the diameters of rings formed in the layer of air between a flat sheet of glass and a lens of known curvature. Seven years after the publication of MicrographiaNewton, then an obscure young academic almost completely unknown, sent his first paper on colors to the Royal Society.

As the resident expert, Hooke was called upon to comment. More than somewhat magisterially, he rejected a new conception of colors he had not taken the trouble to understand. He had merely proposed a mechanism to account for the modification, and he failed now to see that Newton was replacing the concept of modification with an entirely different idea.

The matter dropped for the time, but the complete lack of warmth between the men is manifest from this distance. In addition to optics, the Micrographia also expounded a theory of combustion. At least four men in England were actively engaged at this time in investigating combustion and biografia de robert hooke court its analogy with respiration.

It is impossible to distinguish satisfactorily the independent roles of Hooke, Boyle, Richard Lower, and John Mayow; and it is difficult to assess adequately their total work. Individuals in the group, and Hooke among them, have been hailed as precursors—virtually forestallers—of Lavoisier and the discovery of oxygen. Close analysis of the various theories does not support such a judgment.

He identified the salt with that in saltpeter, so that combustion, which usually requires air, can take place in a vacuum when saltpeter is present. There is no occasion to scorn the insight obtained. Along with the other three men, Hooke was impressed by the analogy of combustion and respiration. He carried out experiments before the Royal Society demonstrating that a continued supply of fresh air is as essential to life as it is to fire.

By biografia de robert hooke court the thorax of a dog, destroying the motion of its lungs, and then employing a bellows to maintain a stream of air which passed out of the lungs through holes that he pricked, he demonstrated conclusively that the function of respiration is to bring a constant supply of fresh air into the lungs—not to cool and not to pump, as prevailing theories held, but solely to supply fresh air.

With Mayow and the others, Hooke identified the nitrous salt or spirit in the air as the ingredient essential to life. During the years following MicrographiaHooke found time to conduct demonstrations before the Royal Society and to deliver the Cutlerian lectures despite his activities as surveyor. Part of this work extended earlier investigations—for example, both those on combustion and those on optics—but he also broke new ground.

The Cutlerian lectures contain at least two important scientific discoveries. Nevertheless, no one before him had stated it explicitly. Which is, that the proportion of the strength or power of moving any Body is always in a duplicate proportion of the Velocity it receives from it In many ways the passage was typical of Hooke. The demonstration foundered on its inherent confusions—although it is necessary to add that in the seventeenth century only giants such as Huygens, Leibniz, and Newton succeeded in dispelling similar confusion in dynamics.

In another Cutlerian lecture, Hooke announced the three basic suppositions on which he intended to construct a system of the world corresponding to the rules of mechanics:. First, That all Coelestial Bodies whatsoever, have an attraction or gravitating power towards their own Centers, whereby they attract not only their own parts, and keep them from flying from them, as we may observe the earth to do, but that they do also attract all the other Coelestial Bodies that are within the sphere of their activity The second supposition is this, That all bodies whatsoever that are put into a direct and simple motion, will so continue to move forward in a streight line, till they are by some other effectual powers deflected and bent into a Motion, describing a Circle, Ellipsis, or some other more compounded Curve Line.

The third supposition is, That these attractive powers are so much the more powerful in operating, by how much the nearer the body wrought upon is to their own Centers. It contains two elements. On the one hand, it proposes a concept of apparently universal attraction. It is only apparently universal, however. An idea of gravitational attractions specific to each planet, forces by which they maintain the unity of their systems, was widely held in the seventeenth century.

Although Hooke took a major step toward generalizing this idea, his understanding of gravitation never eliminated the notion of a force specific to certain kinds of matter and hence never reached the level of universal gravitation. Comets are not related, and they are repelled. Hooke himself never laid claim to the concept of universal gravitation.

Rather, he asserted his propriety over the second element in the passage above, the celestial dynamics. In fact, his proposal did contain a revolutionary insight that reformulated the approach to circular motion in general and to celestial dynamics in particular. Notable in his statement is the absence of any reference to centrifugal force. Hooke was the man who first saw clearly the elements of orbital dynamics as we continue to accept them.

If the principle of rectilinear inertia be granted, a body revolving in an orbit must be continually diverted from its inertial path by some force directed toward a center. When Hooke was formulating this view, Newton still thought of circular motion in terms of an equilibrium of centrifugal and centripetal forces. Moreover, it was Hooke who taught him to see it otherwise.

The correspondence is too well known to need repeating. Hooke was always convinced thereafter that Newton had stolen the inverse square relation from him. Newton himself acknowledged in that the correspondence with Hooke stimulated him to demonstrate that an elliptical orbit around a central attracting body placed at one focus entails an inverse square force.

Nevertheless, one must beware of attributing too much to Hooke. Once again, his power of analysis could not support the brilliance of his insight. The insight cannot be taken from him. Where earlier investigations of the dynamics of circular motion had based themselves on the notion of centrifugal force, Hooke as it were stood the problem right side up and put it in a position to be attacked fruitfully.

But his own mechanics was not adequate to that job. Although he proposed the problem of the dynamics of elliptical orbits, he acknowledged his inability to solve it; and his very derivation of the inverse square relation, on which he insisted with such vehemence, was so defective as to be ludicrous. Hooke did not discover or even approach the law of universal gravitation.

Geology might almost have been created to display his talents to maximum advantage. An almost untouched field, it presented no massive volume of data to be mastered and offered few constraints to curb his facile imagination. Hooke repaid it handsomely. In regard to the latter, Hooke may be described as a protocrystallographer. He showed how the polyhedral forms of crystals as he saw them under the microscope could be built up from packings of bullets, the basis for the claim that he anticipated Steno in the law of constancy of interfacial angles.

In an age when the biblical account of creation made fossils with organic forms a riddle to most investigators, Hooke was remarkable for his steadfast refusal to consider them as anything but the remains of organic creatures. His refutation of the argument that they are lusus naturaesports of nature produced to no purpose, is one of the classic passages of scientific argumentation in the seventeenth century.

He refused to call in the Deluge to explain the presence of marine fossils far from the sea, but he concluded that the surface of the earth has been subject to vast upheavals and changes. When fossils could not be identified with existing creatures, he did not hesitate to consider the mutability of species. Unable to destroy the preconception of a limited time span, he identified the upheavals of the surface of the earth with cataclysmic earthquakes.

He has been called the first uniformitarian; quite the contrary, he was the first catastrophist. The mutations of species he conceived were limited variations under the stress of environmental change. To say as much is only to concede that Hooke could not leap from the seventeenth century into the nineteenth. With the possible exception of Steno, he was easily the most important geologist of his day.

In nothing does he appear more modern than in his prescription of a program for geological study.