ROBERT,** a very eminent English mathematician and philosopher, was the son of Mr John Hooke minister of Freshwater, in the Isle of Wight, where he was born in 1635. He very early discovered a genius for mechanics, by making curious toys with great art and dexterity. He was educated under Dr Buthby in Westminster school; where he not only acquired a competent share of Greek and Latin, together with an insight into Hebrew and some other Oriental languages, but also made himself master of a considerable part of Euclid's elements. About the year 1653 he went to Christ-church in Oxford, and in 1655 was introduced to the Philosophical Society there; where, discovering his mechanical genius, he was first employed to assist Dr Willis in his operations in chemistry, and afterwards recommended to the honourable Robert Boyle, whom he served several years in the same capacity. He was also intrusted in astronomy about this time by Dr Seth Ward, Savilian professor of that science; and from henceforward distinguished himself by many noble inventions and improvements of the mechanic kind. He invented several astronomical instruments, for making observations both at sea and land; and was particularly serviceable to Mr Boyle in completing the invention of the air-pump. Sir John Cutler having founded a mechanic school in 1664, he settled an annual stipend on Mr Hooke for life, intrusting the president, council, and fellows, of the Royal Society to direct him with respect to the number and subjects of his lectures; and on the 11th of January, 1664-5, he was elected by that society curator of experiments for life, with an additional salary. In 1666 he produced to the Royal Society a model for rebuilding the city of London destroyed by fire, with which the society was well pleased; but although the lord mayor and aldermen preferred it to that of the city surveyor, it was not carried into execution. It is said, by one part of this model of Mr Hooke's, it was designed to have all the chief streets, as from Leaden-hall to Newgate, and the like, to lie in exact straight lines, and all the other cross streets turning out of them at right angles, with all the churches, public buildings, markets, &c., in proper and convenient places. The rebuilding of the city according to the act of parliament requiring an able person to let out the ground to the proprietors, Mr Hooke was appointed one of the surveyors; in which employment he got most part of his estate, as appeared pretty evident from a large iron chest of money found after his death, locked down with a key in it, and a date of the time, which showed it to have been shut up above 30 years.—Mr Oldenburgh, secretary to the Royal Society, dying in 1677, Mr Hooke was appointed to supply his place, and began to take minutes at the meeting in October, but did not publish the Transactions. In the beginning of the year 1687, his brother's daughter, Mrs Grace Hooke, who had lived with him several years, died; and he was so affected with grief at her death, that he hardly ever recovered it, but was observed from that time to become less active, more melancholy, and even more cynical than ever. Hooke ever. At the same time, a chancery suit in which he was concerned with Sir John Cutler, on account of his salary for reading the Cutlerian lectures, made him very uneasy, and increased his disorder. In 1691, he was employed in forming the plan of the hospital near Hoxton, founded by Robert Ask alderman of London, who appointed Archbishop Tillotson one of his executors; and in December the same year, Hooke was created doctor of physic, by a warrant from that prelate. In June 1696, the chancery suit with Sir John Cutler was determined in his favour, to his inexplicable satisfaction. His joy on that occasion was found in his diary thus expressed; DOMSILGISSA: that is, Deo Optimo, Maximo, fit honor, laus, gloria, in secula seculorum, Amen. "I was born on this day of July 1635, and God hath given me a new birth: may I never forget his mercies to me! while he gives me breath may I praise him!"

In the same year 1696, an order was granted to him for repeating most of his experiments at the expense of the Royal Society, upon a promise of his finishing the accounts, observations, and deductions from them, and of perfecting the description of all the instruments contrived by him; but his increasing ill-health and general decay rendered him unable to perform it. He continued some years in this wasting condition; and thus languishing till he was quite emaciated, he died March 3rd 1702, at his lodgings in Gresham college, and was buried in St Helen's church, Bishopsgate street; his corpse being attended by all the members of the Royal Society then in London.

Dr Hooke's character, in some respects, was not one of the most amiable. In his person he exhibited but a mean appearance, being short of stature, very crooked, pale, lean, and of a meagre aspect, with lank brown hair, which he wore very long, and hanging over his face. Suitable to his person, his temper was penurious, melancholy, mistrustful; and, though possessed of great philosophical knowledge, he had so much ambition, that he would be thought the only man who could invent or discover; and thus it has been affected by some, that he frequently laid claim to the inventions and discoveries of others, while he boasted of many of his own which he never communicated. On the contrary his admirers have retorted the charge, and have blamed others with claiming the discoveries of this philosopher. Without deciding on this point, which seems at least somewhat doubtful, we shall leave our readers to judge for themselves, after recommending to their perusal the history of the inventions claimed by Dr Hooke at the end of this article, and the note under the article WATCH, both drawn up, we believe, by Professor Robison. In the religious part of his character he was so far exemplary, that he always expressed a great veneration for the Deity; and seldom received any remarkable benefit in life, or made any considerable discovery in nature, or invented any useful contrivance, or found out any difficult problem, without setting down his acknowledgment to God, as many places in his diary plainly show. He frequently studied the sacred writings in the original; for he was acquainted with the ancient languages, as well as with all parts of the mathematics.—He wrote, 1. Lectiones Cutleriae, or Cutlerian Lectures. 2. Micrographia, or Descriptions of minute bodies made by magnifying glasses. 3. A description of heliographs. 4. A description of some mechanical improvements of lamps and water-poles, quarto. 5. Philosophical collections. After his death were published, 6. Posthumous works collected from his papers by Richard Waller secretary to the Royal Society.

Chronological History of Inventions and Discoveries by Dr Hooke.

1656, Barometer, a weather-glass. 1657, A escapement, for maintaining the vibration of a pendulum.—And not long after, the regulating or balance-spring for watches. 1658, The double barrelled air-pump.—The conical pendulum.—His first employment of the conical pendulum was no less ingenious and scientific than it was original. He employed it to represent the mutual gravitation of the planets; a fact which he had most systematically announced. He had shewn, that a force, perfectly analogous to gravity on this earth, operated on the surface of the moon and of Jupiter. Considering the numerous round pits on the surface of the moon, surrounded with a sort of wall, and having a little eminence in the middle, as the production of volcanoes, he inferred, that the ejected matter fell back again to the moon, as such matter falls back again to the earth. He saw Jupiter surrounded with an atmosphere, which accompanied him; and therefore supposed on him, as our air presides on the earth;—He inferred, that it was the same kind of power that maintained the sun and other planets in a round form. He inferred a force to the sun from the circulation round him, and he called it a gravitation; and said that it was not the earth which described the ellipse, but the centre of gravity of the earth and moon. He therefore made a conical pendulum, whose tendency to a vertical position represented the gravitation to the sun, and which was projected at right angles to the vertical plane; and showed experimentally, how the different proportions of the projectile and centripetal tendencies produced various degrees of eccentricity in the orbit. He then added another pendulum, describing a cone round the first, while this described a cone round the vertical line, in order to see what point between them described the ellipse. The results of the experiment were intricate and unsatisfactory; but the thought was ingenious. He candidly acknowledged, that he had not discovered the true law of gravitation which would produce the description of an ellipse round the focus, owing to his want of due mathematical knowledge; and therefore left this investigation to his superiors. Sir Isaac Newton was the happy man who made the discovery, after having entertained the same notions of the forces which connected the bodies of the solar system, before he had any acquaintance with Dr Hooke, or knew of his speculations.

1660, The engine for cutting clock and watch-wheels.—The chief phenomena of capillary attraction.—The freezing of water a fixed temperature. 1663, The method of supplying air to a diving bell.—The number of vibrations made by a musical chord. 1664, His Micrographia was, by the council of the Royal Society, ordered to be printed; but in that work are many just notions respecting respiration, the composition... position of the atmosphere, and the nature of light, which were afterwards attributed as discoveries to Mayow and others, who, though we are far from supposing that they stole their discoveries from Dr Hooke, were certainly anticipated by him.

1666, A quadrant by reflection.

1667, The marine barometer.—The gage for founding unfathomable depths.

1668, The measurement of a degree of the meridian, with a view to determine the figure of the earth, by means of a zenith sector.

1669, The fact of the conservatio virium vivarum, and that in all the productions and extinctions of motion, the accumulated forces were as the squares of the final or initial velocities. This doctrine he announces in all its generality and importance, deducing from it all the consequences which John Bernoulli values himself so highly upon, and which are the chief facts adduced by Leibnitz in support of his doctrine of the forces of bodies in motion. But Hooke was perfectly aware of their entire correspondence with the Cartesian or common doctrine, and was one of the first in applying the celebrated 39th proposition of Newton's Principia to his former positions on this subject, as a mathematical demonstration of them.

1673, That the catenaria was the best form of an arch.

1674, Steam engine on Newcomen's principle.

1679, That the air was the sole source of heat in burning: That combustion is the solution of the inflammable vapour in air; and that in this solution the air gives out its heat and light. That nitre explodes and causes bodies to burn without air, because it consists of this air, accompanied by its heat and light in a condensed or solid state; and air supports flame, because it contains the same ingredients that gunpowder doth, that is, a nitrous spirit: That this air diffuses something in the blood while it is exposed to it in the lungs in a very expanded surface, and when saturated with it, can no longer support life nor flame; but in the act of solution, it produces animal heat: That the arterial and venal blood differ in account of this something being wanting in one of them. In short, the fundamental doctrines of modern chemistry are systematically delivered by Dr Hooke in his Micrographia, published in 1664, and his Lampas, published in 1677.

1680, He first observed the secondary vibrations of elastic bodies, and their connection with harmonic sounds. A glass containing water, and excited by a fiddletick, threw the water into undulations, which were square, hexagonal, octagonal, &c., shewing that it made vibrations subordinate to the total vibration; and that the fundamental sound was accompanied by its octave, its twelfth, &c.

1681, He exhibited musical tones by means of toothed wheels, whirled round and rubbed with a quill, which dropped from tooth to tooth, and produced tones proportioned to the frequency of the cracks or snaps.

1684, He read a paper before the Royal Society, in which he affirms, that some years before that period he had proposed a method of discovering at a distance, not by sound, but by sight. He then proceeds to describe a very accurate and complete telegraph, equal, perhaps, in all respects to those now in use. But some years previous to 1684, Mr. Amontons had not invented his telegraph; so that, though the Marquis of Worcester unquestionably gave the first hint of this invention, Dr Hooke appears to have first brought it to perfection. See Telegraph; and a book, published 1726, entitled Philosophical Experiments and Observations of the late eminent Dr Robert Hooke.

To him also we are indebted for many other discoveries of lesser note; such as the wheel barometer, the universal joint, the manometer, screw divided quadrant, telescopic sights for astronomical instruments, representation of a muscular fibre by a chain of bladders, experiments shewing the inflection of light, and its attraction for solid bodies, the curvilinear path of light through the atmosphere.

Hooke, Nathaniel, author of an esteemed Roman history and other performances. Of this learned gentleman the earliest particulars to be met with are furnished by himself, in the following model but manly address to the earl of Oxford, dated Oct. 7, 1722:

"My Lord, the first time I had the honour to wait Nicholas's upon your lordship since your coming to London, Anecdotes of your lordship had the goodness to ask me, what way &c. of life I was then engaged in? A certain mauvais honneur hindered me at that time from giving a direct answer. The truth is, my lord, I cannot be said present to be in any form of life, but rather to live extempore. The late epidemical distemper seized me, I endeavoured to be rich, imagined for a while that I was, and am in some measure happy to find myself at this instant but just worth nothing. If your lordship, or any of your numerous friends, have need of a servant, with the bare qualifications of being able to read and write, and to be honest, I shall gladly undertake any employments your lordship shall not think me unworthy of. I have been taught, my lord, that neither a man's natural pride, nor his self-love, is an equal judge of what is fit for him; and I shall endeavour to remember, that it is not the short part we act, but the manner of our performance, which gains or loses us the applause of Him who is finally to decide of all human actions. My lord, I am just now employed in translating from the French, a History of the Life of the late archbishop of Cambrai; and I was thinking to beg the honour of your lordship's name to protect a work which will have so much need of it. The original is not yet published. 'Tis written by the author of the Discourse upon Epic Poetry, in the new edition of Telemache. As there are some passages in the book of a particular nature, I dare not solicit your lordship to grant me the favour I have mentioned, till you first have perused it. The whole is short, and pretty fairly transcribed. If your lordship could find a spare hour to look it over, I would wait upon your lordship with it, as it may possibly be no unpleasing entertainment. I should humbly ask your lordship's pardon for so long an address in a season of so much business. But when should I be able to find a time in which your lordship's goodnes is not employed? I am, with perfect respect and duty, my lord, your lordship's most obliged, most faithful, and most obedient humble servant, Nathaniel Hooke." The translation here spoken of was afterwards printed in 1720, 1723. From this period till his death, Mr Hooke enjoyed the confidence and patronage of men not less distinguished by virtue than by titles. In 17... he published a translation... Hooke took the opportunity of publicly testifying his just esteem for a worthy friend, to whom he had been long and much obliged," by telling Mr Pope, that the displaying of his name at the head of those sheets was "like hanging out a splendid sign, to catch the traveller's eye, and entice him to make trial of the entertainment the place affords. But, (he proceeds), when I can write under my sign, that Mr Pope has been here, and was content, who will question the goodness of the house?" The volume is introduced by "Remarks on the History of the Seven Roman Kings, occasioned by Sir Isaac Newton's objections to the supposed 244 years duration of the royal state of Rome." His nervous pen was next employed in digesting "An Account of the conduct of the Dowager-duchess of Marlborough, from her first coming to court to the year 1710, in a Letter from herself to Lord —— in 1742," 8vo. His reward on this occasion was considerable; and the reputation he acquired by the performance much greater. The circumstances of this transaction are thus related by Dr Maty, in his Memoirs of Lord Chesterfield, vol. i. p. 116. "The relict of the great duke of Marlborough, being desirous of submitting to posterity her political conduct, as well as her lord's, applied to the earl of Chesterfield for a proper person to receive her information, and put the memoirs of her life into a proper dress. Mr Hooke was recommended by him for that purpose. He accordingly waited upon the duchess, while she was still in bed, opprest by the infirmities of age. But, knowing who he was, she immediately got herself lifted up, and continued speaking during six hours. She delivered to him, without any notes, her account in the most lively as well as the most connected manner. As she was not tired herself, she would have continued longer the business of this first fitting, had not she perceived that Mr Hooke was quite exhausted, and wanted refreshment as well as rest. So eager was she for the completion of the work, that she insisted upon Mr Hooke's not leaving her house till he had finished it. This was done in a short time; and her Grace was so well pleased with the performance, that she complimented the author with a present of £1000, a sum which far exceeded his expectations. As soon as he was free, and permitted to quit the house of his benefactress, he hastened to the earl, to thank him for his favour, and communicate to him his good fortune. The perturbation of mind he was under, occasioned by the strong sense of his obligation, plainly appeared in his stammering out his acknowledgments: and he, who had succeeded so well as the interpreter of her Grace's sentiments, could scarcely utter his own." The second volume of his Roman history appeared in 1745; when Mr Hooke embraced the fair occasion of congratulating his worthy friend the earl of Marchmont, on "that true glory, the conferring praise of the honest and the wife," which his lordship had so early acquired. To the second volume Mr Hooke added "The Capitoline Marbles, or Concular Calendars, an ancient Monument accidentally discovered at Rome in the year 1545, during the Pontificate of Paul III." In 1738 Mr Hooke published Observations on, I. The Answer of M. P'Abbe de Vertot to the earl of Stanhope's Inquiry concerning the Senate of ancient Rome; dated December 1716. II. A Dissertation upon the Constitution of the Roman Senate, by a Gentleman: published in 1743. III. A Treatise on the Roman Senate, by Dr Conyers Middleton: published in 1747. IV. An Essay on the Roman Senate, by Dr Thomas Chapman: published in 1750;" which he with great propriety inscribed to Mr Speaker Onslow. The third volume of Mr Hooke's Roman History to the end of the Gallic war, was printed under his inspection before his last illness; but did not appear till after his death, which happened in 1764. The fourth and last volume was published in 1771. Mr Hooke left two sons; of whom one is a divine of the church of England; the other, a doctor of the Sorbonne, and professor of astronomy in that illustrious seminary.