Inventors

"The Astreonomical Elements of the Motions in a Parabolick Orb of all the Comets that have been hitherto duly obferv'd. ...This Table needs little Explication, since 'tis plain enough from the Titles, what the Numbers mean. Only it maybe observ'd, that the Perihelium Distances, are estimated in such Parts, as the Middle Distance of the Earth from the Sun, contains 100000."

"These necessary Things premis'd, let it be propos'd to compute the apparent Place of any one of the mention'd Comets, for any Given Time."

"5. From these Things given (by the very same Rules that we find the Planets Places, from the Suns Place and Distance given) we may obtain the Apparent or Geocentrick Place of the Comet, together with the Apparent Latitude. And this it may be worth while to illustrate by an Example or two."

"Wherefore (following the Steps of so Great a Man) I have attempted to bring the same Method to Arithmetical Calculation; and that with desired Success. For, having collected all the Observations of Comets I could, I fram'd this Table, the Result of a prodigious deal of Calculation, which, tho' but small in Bulk, will be no unacceptable Present to Astronomers. For these Numbers are capable of Representing all that has been yet observ'd about the Motion of Comets, by the Help only of the following General Table; in the making of which I spar'd no Labour, that it might come forth perfect, as a Thing consecrated to Posterity, and to last as long as Astronomy it self."

"After this manner... the Astronomical Reader may examine these Numbers, which I have calculated, with all imaginable Care, from the Observations I have met with. And I have not thought fit to make them publick before they have been duly examin'd, and made as accurate as 'twas possible, by the Study of many Years. I have publish'd this Specimen of Cometical Astronomy, as a Prodromus of a designed future Work, left, happening to die, these Papers might be lost, which every Man is not capable to retrieve, by reason of the great Difficulty of the Calculation."

"By comparing together the Accounts of the Motions of these Comets, 'tis apparent, their Orbits are dispos'd in no manner of Order; nor can they, as the Planets are, be comprehended within a Zodiack, but move indifferently every Way, as well Retrograde as Direct; from whence it is clear, they are not carry'd about or mov'd in 'Vortices'. Moreover, the Distances in their Perihelium's are sometimes greater, sometimes less; which makes me suspect, there may be a far greater Number of them, which moving in Regions more remote from the Sun, become very obscure; and wanting Tails, pass by us unseen."

"Not long after, that Great Geometrician, the Illustrious Newton, writing his Mathematical Principles of Natural Philosophy, demonstrated not only that what Kepler had found, did necessarily obtain in the Planetary System; but also, that all the Phænomena of Comets wou'd naturally follow from the same Principles; which he abundantly illustrated by the Example of the aforesaid Comet of the Year 1680, shewing, at the same time, a Method of Delineating the Orbits of Comets Geometrically; wherein he (not without the highest Admiration of all Men) solv'd a Problem, whose Intricacy render'd it worthy of himself. This Comet he prov'd to move round the Sun in a Parabolical Orb, and to describe Area's (taken at the Center of the Sun) proportional to the Times."

"At length, came that prodigious Comet of the Year 1680, which descending (as it were) from an infinite Distance Perpendicularly towards the Sun, arose from him again with as great a Velocity. This Comet, (which was Seen for Four Months continually) by the very remarkable and peculiar Curvity of its Orbit (above all others) gave the fittest Occasion for investigating the Theory of the Motion. And the Royal Observatories at Paris and Greenwich having been for some time founded, and committed to the Care of most excellent Astronomers, the apparent Motion of this Comet was most accurately (perhaps as far as Humane Skill cou'd go) observ'd by Mrs. Cassini and Flamsteed."

"Next, Hevelius (a Noble Emulator of Ticho Brahe) following in Keplers Steps, embraced the same Hypothesis of the Rectilinear Motion of Comets, himself accurately observing many of them. Yet, he complain'd, that his Calculations did not perfectly agree to the Matter of Fact in the Heavens: And was aware, that the Path of a Comet was bent into a Curve Line towards the Sun."

"But Seneca the Philosopher, having consider'd the Phænomena of Two remarkable Comets of his Time, made no Scruple to place them amongst the Cœlestial Bodies; believing them to be Stars of equal Duration with the World, tho' he owns their Motions to be govern'd by Laws not as then known or found out. And at last (which was no untrue or vain Prediction) he foretells, that there should be Ages sometime hereafter, to whom Time and Diligence shou'd unfold all these Mysteries, and who shou'd wonder that the Ancients cou'd be ignorant of them, after some lucky Interpreter of Nature had shewn, in what Parts of the Heavens the Comets wander'd, and how great they were."

"Yet almost all the Astronomers differ'd from this Opinion of Seneca; neither did Seneca himself think fit to set down those Phænomena of the Motion, by which he was enabled to maintain his Opinion: Nor the Times of those Appearances, which might be of use to Posterity, in order to the Determining these Things. And indeed, upon the Turning over very many Histories of Comets, I find nothing at all that can be of Service in this Affair, before, A.D. 1337, at which time ', a Constantinopolitan Historian and Astronomer, did pretty accurately describe the Path of a Comet amongst the Fix'd Stars, but was too laxe as to the Account of the Time; so that this most doubtful and uncertain Comet, only deserves to be inserted in our Catalogue, for the sake of its appearing near 400 Years ago."

"[I]n the Year 1472, which being the swiftest of all, and nearest to the Earth, was observ'd by Regiomantanus. This Comet (fo frightful upon the Account both of the Magnitude of its Body,and the Tail) mov'd Forty Degrees of a great Circle in the Heavens, in the Space of one Day, and was the first, of which any proper Observations are come down to us."

"But all those that consider'd Comets, until the Time of Ticho Brahe (that great Restorer of Astronomy) believ'd them to be below the Moon, and so took but little Notice of them, reckoning them no other than Vapours."

"Wherefore, if, according to what we have already said, it should return again about the year 1758, candid posterity will not refuse to acknowledge that this was first discovered by an Englishman."

"But in the Year 1577, (Ticho seriously pursuing the Study of the Stars, and having gotten large Instruments for the Performing Cœlestial Mensurations, with far greater Care and Certainty, than the Ancients cou'd ever hope for) there appear'd a very remarkable Comet; to the Observation of which, Ticho vigorously applied himself; and found by many just and faithful Trials, that it had not a Diurnal Parallax that was at all perceptible: And consequently was not only no Aireal Vapour, but also much higher than the Moon; nay, might be plac'd amongst the Planets for any thing that appear'd to the Contrary; the cavilling Opposition made by some of the School-men in the mean time, being to no Purpose."

"Next to Ticho, came the Sagacious Kepler. He having the Advantage of Tichos Labours and Observations, found out the true Physical System of the World, and vastly improv'd the Astronomical Science. For he demonstrated that all the Planets perform their Revolutions in Elliptick Orbits, whose 'Plains pass thro' the Center of the Sun, observing this Law, That the Area's (of the Elliptick Sectors, taken at the Center of the Sun, which he proved to be in the common Focus of these Ellipses) are always proportional to the Times, in which the correspendent Elliptical Arches are describ'd. He discover'd also, That the Distances of the Planets from the Sun are in the Ratio [3:2] of the Periodical Times, or (which is all one) That the Cubes of the Distances are as the Squares of the Times. This great Astronomer had the Opportunity of observing Two Comets, one of which was a very remarkable one. And from the Observations of these (which afforded sufficient Indications of an Annual Parallax) he concluded, That the Comets mov'd freely thro' the Planetary Orbs, with a Motion not much different from a Rectilinear one; but of what Kind, he cou'd not then precisely determine."

"So that 'tis to the Greeks themselves as the Inventors (and especially to the Great Hipparchus) that we owe this Astronomy, which is now improv'd to such a Heigth. But yet, amongst these, the Opinion of Aristotle (who wou'd have Comets to be nothing else, but Sublunary Vapours, or Airy Meteors) prevailed so far, that this most difficult Part of the Astronomical Science lay altogether neglected; for no Body thought it worth while to take Notice of, or write about, the Wandring uncertain Motions of what they esteemed Vapours floating in the Æther; whence it came to pass, that nothing certain, concerning the Motion of Comets, can be found transmitted from them to us."

"Anno Domini 1666 the great conflagration of London happened, and then he was chosen one of the two surveyors of the citie of London; by which he hath gott a great estate. He built Bedlam, the Physitians' College, Montague-house, the Piller on Fish-street-hill, and Theatre there; and he is much made use of in designing buildings."

"As he is of prodigious inventive head, so is a person of great vertue and goodnes. Now when I have sayd his inventive faculty is so great, you cannot imagine his memory to be excellent, for they are like two bucketts, as one goes up, the other goes downe. He is certainly the greatest mechanick this day in the world. His head lies much more to Geometry then to Arithmetique."

"'Twas Mr Robert Hooke that invented the Pendulum Watches, so much more usefull than the other watches."

"Anno Domini 1662 Mr. Robert Boyle recommended Mr. Robert Hooke to be Curator of the Experiments of the Royall Society, wherin he did an admirable good worke to the Common-wealth of Learning, in recommending the fittest person in the world to them. Anno 1664 he was chosen Geometry Professour at Gresham College."

"All his Errors and Blemishes were more than made amends for, by the Greatness and Extent of his natural and acquired Parts, and more than common, if not wonderful Sagacity, in diving into the most hidden secrets of Nature, and in contriving proper Methods of forcing her to confess the Truth. ...There needs no other Proof for this than the great number of Experiments he made, with the Contrivances for them, amounting to some hundreds; his new and useful Instruments and Inventions, which were numerous, his admirable Facility and Clearness, in explaining the Phænomena of Nature, and demonstrating his Assertions; his happy Talent in adapting Theories to the Phænomena observ'd, and contriving easy and plain, not pompous and amusing, Experiments to back and prove those Theories; proceeding from Observations to Theories, and from Theories to farther trials, which he often asserted to be the most proper method to succeed in the interpretation of Nature. For these, his happy Qualifications, he was much respected by the most learned Philosophers both at home and abroad: And as with all his Failures, he may be reckon'd among the great Men of the last Age, so had he been free from them, possibly, he might have stood in the Front. But humanum est errare."

"When he went to Mr Busby's, the schoolemaster of Westminster, at whose howse he was; and he made very much of him. ...There he learnd to play 20 lessons on the organ. He there in one weeke's time made himselfe master of the first Vl bookes of Euclid, to the admiration of Mr. Busby... who introduced him. At schoole here he was very mechanicall, and (amongst other things) he invented thirty severall wayes of flying, which I have not only heard him say, but Dr. Wilkins (at Wadham College at that time) who gave him his Mathematical Magique which did him a great kindnes. He was never a King's Scholar, and I have heard Sir Richard Knight (who was his school-fellow) say that he seldome sawe him in the schoole."

"He always exprest a great Veneration for the eternal and immense Cause of all Beings, as may be seen in very many Passages in his Writings, and seldom receiv'd any remarkable Benefit from God without thankfully ackowledging the Mercy; never made any considerable discovery in Nature, invented any useful Contrivance, or found out any difficult Problem, without setting down his Acknowledgement to the Omnipotent Providence, as many places in his Diary testify, frequently in these or the like words, abbreviated thus, DOMGM. and was a frequent studier of the Holy Scripture in the Originals: If he was particular in some Matters, let us leave him to the searcher of Hearts."

"Anno Domini 1658... he was sent to Christ Church in Oxford, where he had a chorister's place (in those dayes when the church musique was putt downe), which was a pretty good maintenance. He was there assistant to Dr. Thomas Willis in his chymistry; who afterwards recommended him to the honble Robert Boyle, esqre, to be usefull to him in his chymicall operations. Mr Hooke then read to him (R.B. esqre) Euclid's Elements, and made him understand Des Cartes' Philosophy."

"He hath invented an engine for the speedie working of division, etc., or for the speedie and immediate finding out the divisor."

"Thence with Creed to Gresham College, where I had been by Mr. Povy the last week proposed to be admitted a member; and was this day admitted... But it is a most acceptable thing to hear their discourse, and see their experiments; which were this day upon the nature of fire... Above all, Mr. Boyle to-day was at the meeting, and above him Mr. Hooke, who is the most, and promises the least, of any man in the world that ever I saw."

"November the 29th 1693, Dr Hook read a Discourse concerning Microscopes, their Uses and Advantages in discovering the Textures and Motions of Bodies, as well animate as inanimate; observing, that all Examinations by Fire, or Chymical Menstruums, destroyed or altered the compounding Particles, or mix'd them with, and confounded them with heterogeneous Parts of the Fire, or Menstruum, made Use of; whereas the Microscope discovers them in their natural State and Actions. Observing farther, that the Motions of the Viscera and of the Fluids, in the small Vessels, are, by that Instrument, to be seen, by their different Colours and Refractions, through the transparent Skins and Bodies of many Insects: Natural History, hitherto, being for the most Part only conversant about the outward Shape and Colour of Plants, Animals, and the like; but the Microscope would afford a very large Field of Enquiries and Observations not yet much cultivated, which he recommends as one of the most proper Ways of discovering the true Texture and Mechanism of Bodies."

"The case of the sixth Corrollary obtains in the celestial bodies (as Sir Christopher Wren, Dr. Hooke, and Dr. Halley have severally observed); and therefore in what follows, I intend to treat more at large of those things which relate to centripetal force, decreasing as the squares of the distances from the centres inverse square law]."

"When any body is strained beyond a certain amount and then released, it fails to return completely to its original form and volume or it retains a permanent set. The largest strain of any kind which a body may undergo and still completely recover from when released is called the limit of elasticity for that form of strain, and the corresponding stress is called the limiting stress. The limit of elasticity is... widely different for different substances. Thus, rubber may be greatly extended and yet recover, while the limit for glass and ivory is very small. ... Within the limit of elasticity a simple law, first stated by Hooke in 1676 and known as Hooke's law, holds, namely, "stress is proportional to strain." (Hooke's statement in Latin was "Ut tensio sic vis.") Hooke illustrated his law by various cases of strain, such as the stretching of a spiral spring and of a wire, the bending of a beam, the twisting of a wire, and so on."

"That plants and animals are composed of cells was not revealed until the invention of the microscope, which although very rude in its construction and efficiency as compared with microscopes of today, was beginning to be employed by Robert Hooke (1635-1703) and others in the seventeenth century in the study of plants. Robert Hooke, one of the earliest to study plants with the microscope, examined thin sections of cork, and found the cork to be composed of numerous small compartments which he called cells on account of their rough resemblance to the cells of a honeycomb."

"Being subject to headache which hindered his learning his father laid aside all thought of breeding him a scholar, and finding himself also grow very infirm through age and sickness, wholly neglected his further education, who, being thus left to himself, spent his time in making little mechanical 'Toys, (as he says) in which he was very intent, and for the Tools he had successful; so that there was nothing he saw done by any Mechanick but he endeavoured to imitate, and in some particular could exceed (which are his own words).' His Father, observing by these Indications, his great inclination to Mechanicks, thought to put him Apprentice to some easy Trade (as a Watchmakers or Limners) he shewing most inclination to those or the like Mechanical Performances; for making use of such Tools as he could procure, 'seeing an old Brass Clock taken to pieces, he attempted to imitate it, and made a wooden one that would go: 'Much about the same time he made a small Ship about a Yard long, fitly shaping it, adding its Rigging of Ropes, Pullies, Masts, &c. with a contrivance to make it fire off some small Guns, as it was Sailing cross a Haven of a pretty breadth: He had also a great fancy for drawing, having much about the same Age Coppied several Prints with a Pen, that Mr. Hoskins (Son to the famous Hoskins Cowpers Master) much admired one not instructed could so well imitate them."

"The flexible chain, hanging under the action of applied force, will assume a certain shape, namely the catenary if the chain is subjected only to its own weight, or a if the load is uniformly distributed horizontally. Whatever the load, there will be a corresponding shape, and the structural action in all cases is the same; purely tensile forces are transmitted along the centre line of the chain. As Hooke saw in 1675 with his ut pendet continuum flexile, sic stabit contiguum rigidum inversum, ...a hanging chain may be inverted to give a satisfactory arch to carry the same loads, but working in compression rather than tension. The compressive arch, however, if of vanishingly small thickness, would be in unstable equilibrium, and stability is conferred in practice by making the arch ring of finite depth."

"The next moneth he published another little... pamphlet,—Discourse of a new instrument he haz invented to make more accurate observations in astronomy then ever was yet made, or could be made by any instruments hitherto invented, and this instrument... performes more, and more exact, then all the chargeable apparatus of the noble Tycho Brache or the present Hevelius of Dantzick."

"Historically, the investigations of oscillatory motions was motivated by the desire to improve methods of telling time. ...In the seventeenth century the need to measure small periods of time accurately for the purpose of telling longitude at sea caused scientists to search for increasingly accurate clocks. The search resulted in some major successes that were at least as valuable for the advancement of mathematics and the study of other phenomena of nature, such as light and sound, as they were for the specific problem of measuring time. Scientists naturally concentrated on any physical phenomena that seemed to be periodic or repetitive and might therefore be related to the periodic motion of the planets. Two phenomena recommended themselves for closer investigation, the motion of an object or bob... on a spring, and the motion of a pendulum. The first of those attracted the attention of Robert Hooke... Suppose d is the increase or decrease in the length of the spring resulting from extension or contraction. Hooke found that the restoring force the spring exerts is proportional to d; that is, the force is a constant k, say, times d. This is the meaning of [Ut tensio, sic vis ("as the extension, so the force")]..."

"He could... produce delightful drawings. Hooke was justifiably proud of his skills as an artist. It was a talent that he shared with his college friend Christopher Wren—by the late 1650s they had begun making exquisite drawings of insects and other natural phenomena viewed with the high-magnification help of the new microscope."

"From his Youth he had been us'd to a Collegiate, or rather Monastick Life, which might be some reason of his continuing to live so like an Hermit or Cynick too penuriously, when his Circumstances, as to Estate, were very considerable, scarcely affording himself Necessaries. I indeed, as well as others, have heard him declare sometimes that he had a great Project in his Head as to the disposal of the most part of his Estate for the advancement of Natural Knowledge, and to promote the Ends and Designs for which the Royal Society was instituted... But tho he was often solicited by his Friends to put his Designs down in Writing, and make his Will as to the disposal of his Estate to his own liking in the time of his Health; and after when himself, and all thought, his End drew near, yet he could never be prevail'd with to perfect it, still procrastinating it, till at last this great Design prov'd an airy Phantom and vanish'd into nothing. Thus he dy'd at last without any Will and Testament that could be found."

"Hooke merited a larger share of the admiration of posterity than has hitherto been awarded to him..."

"Robert Hooke was the first to announce that the force of the spring is as its angular distance from its position of rest. It seems, indeed, from his posthumous works, edited by Waller.... that Hooke, as early as 1656, had under the form of an anagram, expressed the law Ut pondus sic tensio. I have therefore little doubt that to Hooke we owe the invention of the fusee, one of the most beautiful of the many contrivances required to make a perfect timekeeper."

"The possession of two such men as Newton and Hooke is rarely granted to one generation. They were not equal, however, in their greatness. But, while ample justice has been done to the genius of Newton, the labours of Hooke have been sadly overlooked. Hooke's misfortune lay more in his nearness to one whose greater glory paled his lesser light, than in any dimness in his own effulgence. But his nearness in time to Newton was not the only obstacle to his fame. He wanted method. His brain was too busy and ready to devise more than his hands could execute or his pen describe, and the eager student of his works, while ready to grasp a new fact or full-grown thought, is too often doomed to disappointment by his quaint remark, "But of this by and by." This by and by rarely comes, or if ever, almost always in the wrong place. In a discourse of earthquakes, for instance, we find descriptions of a new telescope, the exact orientation of Westminster as evidencing the variation of the compass, and observations on the setting of the sun-dial in the Privy Gardens at Whitehall."

"Some other Course therefore must be taken to promote the Search of Knowledge. Some other kind of Art for Inquiry than what hath been hitherto made use of, must be discovered; the Intellect is not to he suffer'd to act without its Helps, but is continually to be assisted by some Method or Engine, which shall be as a Guide to regulate its Actions, so as that it shall not be able to act amiss: Of this Engine, no Man except the incomparable Verulam hath had any Thoughts, and he indeed hath promoted it to a very good pitch; but there is yet somewhat more to be added, which he seem'd to want time to compleat. By this, as by that Art of Algebra in Geometry, 'twill be very easy to proceed in any Natural Inquiry, regularly and certainly: And indeed it may not improperly be call'd a Philosophical Algebra, or an Art of directing the Mind in the search after Philosophical Truths, for as 'tis very hard for the most acute Wit to find out any difficult Problem in Geometry. without the help of Algebra to direct and regulate the Acts of the Reason in the Process from the question to the quœsitum, and altogether as easy for the meanest Capacity acting by that Method to compleat and perfect it, so will it be in the inquiry after Natural Knowledge."

"About this time, 1655, having an opportunity of acquainting myself with astronomy by the kindness of Dr. Ward, I apply'd myself to the improving of the pendulum for such observations, and in the year 1656, or 1657, I contriv'd a way to continue the motion of the pendulum, so much commended by Ricciolus in his Almagestum which Dr. Ward had recommended to me to peruse. I made some trials to this end, which I found to succeed to my wish. The success of these made me further think of improving it for finding the longitude; and the method I had made for myself for mechanick inventions, quickly led me to the use of springs, instead of gravity, for the making a body vibrate in any posture. Whereupon I did first in great, and afterwards in smaller modules, satisfy myself of the practicableness of such an invention; and hoping to have made great advantage thereby, I acquainted divers of my freinds, and particularly Mr. Boyle, that I was possessed of such an invention, and crav'd their assistance for improving the use of it to my advantage. Immediately after his majesty's restoration Mr. Boyle was pleased to acquaint the lord Brouncher and Sir with it, who advis'd me to get a patent for the invention, and propounded very probable ways of making considerable advantage by it. To induce them to a belief of my performance, I shewed a pocket watch, accommodated with a spring, apply'd to the arbor of the ballance, to regulate the motion thereof, concealing the way I had for finding the longitude. This was so well approv'd of, that Sir Robert Moray drew me up the form of a patent, the principal part whereof, viz. the description of the watch so regulated, is his own hand writing, which I have yet by me. The discouragement I met with in the management of this affair, made me desist for that time."

"[Following Galileo...] The next great inventor and improver of the science of horology was Hooke. In the year 1658 he invented the balance-spring, an improvement of the first importance in the art of timekeeping. ...Immediately after the invention of the balance-spring by Hooke, it was found that as the watches to which the spring was adapted kept so much more accurate time than those formerly made, it became desirable to divide the hour into more minute portions, and so the motion work was invented and the minute-hand applied."

"Having now retrieved a little more of leasure, both for Delineation and Description, for a further elucidation of what I have said, I shall make it my third Attempt, to explain; First, A Helioscope to look upon the body of the Sun, without any offence to the Observers eye. Secondly, A way of shortening reflective and refractive Telescopes. Thirdly, A way of using a Glass of any length, without moving the Tube. Fourthly, An Instrument for taking the Diameters of the Sun, Moon and Planets, or for taking any other Distances, to five or ten Degrees, to the certainty of a Second. ... Fifthly, An Instrument for describing all manner of Dials, by the tangent projection. Sixthly, The uses thereof; 1. For adjusting the Hand of a Clock, so as to make it move in the shadow of a Dial, whose style is parallel to the Axis: Or, 2. In the Azimuth of any Celestial Body, that is, in the shadow of the upright, or any other way inclining Style, upon any plain. 3. For making a Hand move according to the true æquation of Time. 4. For making all manner of Elliptical Dials, in Mr. Foster's way, &c. 5. For communicating a circular motion in a Curve Line, without any shaking: And for divers other excellent purposes."

"The true Mathematical and Mechanical Form of all manner of Arches for building with the true butment necessary to each of them, a Problem which no Architectonick Writer hath ever yet attempted, much less perform'd. ...Ut pendet continaum flexile, sic stabit contiguum rigidum, which is the Linea Catenaria."

"The Reason of the present Animadversions. ...How far Hevelius has proceeded. That his instruments do not much exceed Ticho. The bigness, Sights and Divisions, not considerably differing. Ticho not ignorant of his new way of Division. ... That so great curiosity as Hevelius strives for is needless without the use of Telescopic Sights, the power of the naked eye being limited. That no one part of an Instrument should be more perfect than another. ... That if Hevelius could have been prevail'd on by the Author to have used Telescopic Sights, his observations might have been 40 times more exact than they are. That Hevelius his Objections against Telescopic sights are of no validity; but the Sights without Telescopes cannot distinguish a less angle then half a Minute. That an Instrument of 3 foot Radius with Telescopes, will do more then one of 3 score foot Radius with common Sights, the eye being unable to distinguish. This is proved by the undiscernableness of spots in the Moon, and by an Experiment with Lines on a paper, by which a Standard is made of the power of the eye. ... A Conclusion of the Animadversions. That the learn'd World is obllig'd to Hevelius for what he hath done, but would have more, if he had used other instruments. That the Animadvertor both contrived some hundreds of Instruments, each of very great accurateness for taking Angles, Levels, &c. and a particular Arithmetical lnstrument for performing all Operations in Arithmetick, with the greatest ease, swiftness and certainty imaginable. That the Reader may be the more certain of this, the Author describes an Instrument for taking Angles in the Heavens..."

"Hooke is amazing in the number, the variety and the ingenuity of his experiments as well as for his extraordinary fertility in hypothesis. He followed Bacon in his attempt to demonstrate that the effects of gravity on a body must diminish as the body was sunk into the bowels of the earth. He sought to discover how far the effects were altered at great heights or in the region of the equator; and he threw light on the problem by observations and experiments on the pendulum. From the globular shapes of the heavenly bodies and the stable conformations of the ridges on the moon he deduced that the moon and the planets had gravity; and by 1666 he saw the motion of a comet (for example) as incurvated by the pull of the sun... and suggested that the motion of the planets might be explicable on the kind of principles that account for the motion of a pendulum. In 1674 he was suggesting that by this route one could arrive at a mechanical system of the planets which would be "the true perfection of astronomy." He pointed out that... account must be taken of the force which all heavenly bodies must be presumed to be exerting on one another."

"The Publisher of Transactions in that of October 1675 indeavours to cover former injuries done me by accumulating new ones, and this with so much passion as with integrity to lay by discretion; otherwise he would not have affirmed, that it was as certain that none of my Watches succeeded, as it was that I had made them several years ago: For how could he be sure of a Negative? Whom I have not acquainted with my Inventions, since l looked on him as one that made a trade of Intelligence. Next whereas he says l made them without publishing them to the world in Print, he prevaricates, and would have it believed that they were not published to the world, though they were publickly read of in Sir John Cutlers Lectures before great numbers at several times, and though they were made and shewn to thousands both English and Foreiners, and writ of to several persons absent, and though they were in the year 1665 in the History of the Royal Society published to the world in Print, because, forsooth, they were not printed in his Transactions. Thirdly, whereas the Publisher of Transactions makes along story of my seeing his Journal De Scavans, and my desiring to transcribe that part of it which concerned this matter, as if l had requested some singular favour thereby, l answer, First, that he knew I designed presently to have printed it with Animadversions, but he endeavoured to prevent me, designing first clancularly to get a Patent of it for himself, and thereby to defraud me. Next, I say, I had a right without his favour to have seen, perused, and copied it, as I was one of the Royal Society, the intelligence he there brings in being the Societies. ... To his upbraiding me with his having published some things of Mine; I answer, he hath so, but not so much with mine as with his own desire, and if he send me what I think worth publishing, l will do as much for him, and repay him in his own coyn. Lastly, Whereas he makes use of We and Us ambiguously, it is desired he would explain whether he means the Royal Society, or the Pluralities of himself. If the former, it is not so, as l can prove by many Witnesses; if the later, I neither know what he is acquainted with, or what has been imparted or explained to him. So not designing to trouble my self any further with him, unless he gives me occasion, I dismiss him with his — Speque metuque Procul hinc procul ito."

"In a... controversy with Hevelius, Hooke prejudiced a good cause by bad manners. Hevelius having ignored his recommendation of telescopic sights, he [Hooke] devoted several Cutlerian lectures to unfriendly comments on that 'curious and pompous book,' the 'Machina Cœlestis.' Hooke's acrid, though just, arguments were collected as 'Animadversions on the First Part of the "Machina Cœlestis"' (1674), in which he inserted descriptions of a 'water-level' and of a mode of giving clockwork motion to a parallactic instrument. There is no doubt of Hooke's priority in the application of a spiral spring to regulate the balance of watches; but here again his peevish temper brought him discredit. The invention, arrived at about 1668, was designed to solve the problem of longitudes, and Boyle and Brouncker endeavoured to secure him a patent, but he declined their terms, and concealed the improvement until Huygens rediscovered it in 1675. He then caused some of his 'new watches' to be constructed by Tompion (one of which was presented to Charles II), and published the principle involved in them of the isochronism of springs in the maxim 'ut tensio, sic vis,' appended in cryptographic form to 'A Description of Helioscopes' (1676). A quarrel with Oldenburg on the subject culminated in Hooke's accusation of him as 'a trafficker in intelligence,' an expression which the Royal Society obliged him to withdraw. It was contained in a postscript to his 'Lampas, or a Description of some Mechanical Improvements of Lamps and Water-poises' (1677)."

"At these meetings, which were about the year 1655, divers experiments were suggested, discoursed, and tried with various successes, though no other account was taken of them but what particular persons perhaps did for the help of their own memories; so that many excellent things have been lost. Some few only by the kindness of the authors have since been made public. Among these may be reckoned the Honourable Mr Boyle's Pneumatic Engine and Experiments, first printed in the year 1660; for in 1658 or 1659 I continued and perfected the air-pump for Mr Boyle, having first seen a contrivance for that purpose made for the same honourable person by Mr Gratorix, which was too gross to perform any great matter."