Out of the Shadow of a Giant

by John Gribbin

  sociable, obliging, enthusiastic, and, in terms of the organisation of his efforts, an inveterate optimist. Generous to a fault, he tried valiantly to give adequate attention and time to each of the projects he undertook.

  The only two people Hooke ever fell out with, in each case with good reason, were Newton and Oldenburg, although naturally he had scientific disagreements, as opposed to personal feuds, with others; these included, as we shall see, the astronomer Johannes Hevelius.

  Some days Hooke had to give his Gresham or Cutlerian lectures, and, although these were often poorly attended, the need to prepare them had the happy consequence for us that written records survive of his thoughts on diverse subjects. When the Royal met (at first on Wednesdays, later Thursdays), he had to carry out demonstrations, and after the meetings he would usually be among a group of Fellows who adjourned to a coffee house to burn the midnight oil with philosophical discussions. Even then he would not be finished. Especially after 1674, when he had a turret built on to his rooms at the College, Hooke would stay up until the small hours, and sometimes all night, making astronomical observations. Waller tells us that Hooke was frequently ‘continuing his Studies all Night, and taking a short Nap in the Day’.

  How was it possible for one man to do all this? Partly because Hooke was, as we have said, a chronic insomniac and workaholic. But also because he dosed himself with a fearsome quantity, and even more fearsome quality, of medication for real or imagined illnesses, and drank copious amounts of coffee.

  Lucinda McCray Beier has described Hooke as ‘the great medicine-taker of seventeenth-century England’.fn5 His diary seldom describes any specific ailment, simply remarking that he is ill. But he does mention giddiness, headaches, dizziness and palpitations (all of which, as Jardine has commented, ‘may have been side-effects of the preparations he was consuming’fn6) and seems to have suffered from noises in the head, presumably tinnitus, which he obscured by singing while he worked. He seems to have regarded his bodily ills as something of an opportunity for scientific studies of the value of various ‘cures’, but also took medicines not to treat existing symptoms but in the hope of preventing symptoms that he imagined might otherwise be felt. Even though he actually suffered no major illness during the period when he kept the diary, he would take emetics and purgatives to cleanse his body, sometimes with the result (for example, on 4 September 1672) that he was ‘disordered somewhat by physic’. He would drink Dulwich water, a popular ‘health’ drink from a spring at that location, by the pint, and on occasion tried ‘syrup of poppies’ to help him sleep, resulting in sweaty nights filled with ‘wild, frightful dreams’. For a time, he tried a preparation containing iron and mercury to see what effect it had. He tried tobacco to see if it had medicinal properties, and noted the effects of coffee, chocolate, tea and wine on his body. A not untypical entry reports on 16 February 1673, after using ‘Andrews cordial’, that this:

  brought much slime out of the guts and made me cheerful. Eat dinner with good stomach and pannado at night but drinking posset upon it put me into a feverish sweat which made me sleep very unquiet and much disturbed in my head and stomach. Taking sneezing tobacco about 3 in the morn clear my head much and made me cheerful afterwards. I slept about 2 hours, but my head was disturbed when I waked.

  And on 1 August 1675:

  Took volatile Spirit of Wormwood which made me very sick and disturbed me all the night and purged me in the morning. Drank small beer and spirit of Sal-amoniack. I purged 5 or 6 times very easily upon Sunday morning. This is certainly a great Discovery in Physick. I hope that this will dissolve that viscous slime that hath soe much tormented me in my stomach and guts.

  Hooke, indeed, took so much medication that it was news when he did not. On 3 August 1673, the diary records ‘took no physick’. Beier emphases that there was nothing unusual about the kinds of ‘physick’ that Hooke took, only a few of which we have mentioned here; his contemporaries swallowed much the same preparations. But ‘few people took as much physic as often as did Hooke’. Although he was happy to take medical advice from friends, strangers and supposed wise women, he also consulted the best physicians in London more often than most of his contemporaries. This may have been partly because of the circles he moved in, which gave him access to the medical elite, but it may also reflect his scientific interest in medicine and its effect on the human body, especially his body. Having tried everything, he was certainly well placed to pass on medicinal advice to others, which he happily did.

  One of the effects of all this physic taking, Jardine suggests, was that it ‘excites the mental faculties, producing a clarity which is conducive to slightly fevered intellectual activity of the kind Hooke needed in order to cope with his chronic burden of overwork and the competing demands of clients and employers.’ He operated, she says, ‘under the permanent influence of stimulants’. If so, it may explain his physical decline in later years. But it could also explain how he achieved so much in so many areas, the theme to which we shall now return.

  One of the first significant post-Fire experiments that Hooke was involved in resulted from criticism of his suggestion that breathing supplies the body with the same substance as ‘that which is fixt in Salt-peter’, and is essential for life. In a demonstration to the Royal on 10 October 1667, Hooke and a colleague, the leading anatomist Dr Richard Lower, made small holes in the lung wall of a dog so that its lungs could be kept permanently inflated, with air pumped in from a bellows through one hole and out through the other. The dog ‘lay still as before, his eyes being all the time very quick, & his heart beating very regularly’. This established that the supposed pumping action of the lungs was not important in itself, but was simply the way the body took in fresh air and expelled stale air. In further experiments a little later, stale air from the lungs was recycled until the dog seemed near to death, but the animal recovered when allowed to breathe normally.

  Lower developed these ideas in further studies, which formed the core of his influential book De Corde (On the Heart), published in 1669, where he gave Hooke due credit. But this was the last time Hooke was involved in vivisection, having made a key contribution to the development of an understanding of the way the heart and lungs contribute to the workings of the body.

  Apart from his relative squeamishness discouraging him from further work of this kind, Hooke was busy on other things. His work on pendulums and timekeeping devices never stopped, and we have a detailed description of one contribution thanks to a visitor from Florence, Lorenzo Magalotti, who was at the Royal in February 1668 and reported:

  We also saw a pocket watch with a new pendulum invention. You might call it with a bridle, the time being regulated by a little spring of tempered wire, which at one end is attached to the balance-wheel, and at the other to the body of the watch. This works in such a way that if the movements of the balance-wheel are unequal, and if some irregularity of the toothed movement tends to increase the inequality, the wire keeps it in check, obliging it always to make the same journey. They say that if you keep it hung up, the invention works well and that it corrects the errors of the movement as well as a pendulum, but that if you carry it in your pocket the temper of the wire changes in accordance with the temperature of the body, and getting softer, allows the balance-wheel to turn with more freedom.fn7

  There are two noteworthy things about this description of Hooke’s invention. First, because it is affected by temperature, it does not solve the longitude problem. And, curiously, no record of this demonstration survives in the official Royal Society records, which at the time were the responsibility of Henry Oldenburg, whom Hooke suspected, on the basis of very persuasive evidence, of being in cahoots with Christiaan Huygens in an attempt to get patent rights for the Dutchman’s chronometer. Indeed, as ‘Espinasse has pointed out, this was not the first time that Oldenburg ‘omitted to record the demonstrations’ of Hooke’s timekeepers. Coincidence?

  One seemingly minor aspect of Hooke’s activities in
the late 1660s is sometimes overlooked, but shows great insight. He tried mixing gold and lead to see if they would combine to form a substance denser than either of them. This was not the work of an old-school alchemist, but was based on the idea that there might be gaps between the particles of each element into which particles of the other substance might penetrate, filling in the gaps. This wasn’t quite the concept of atoms, but it came mighty close.

  Another development in 1668 had more immediate implications, and would eventually involve the other main character in our story, Edmond Halley. In June that year, Oldenburg received a request from Johannes Hevelius, a German based in Danzig and Europe’s leading astronomer of the time. Hevelius, who had been born in 1611, was an astronomer of the old school. He had a superb observatory equipped with the finest quadrants and other ‘open sight’ instruments, and large, but not quite so fine, telescopes. He made his measurements of stellar positions, and (for example) the way a comet moved past the background stars using ‘open sights’, and was convinced that this was more accurate then the use of the telescopic sights attached to such instruments, which Hooke and Wren had pioneered and which Hooke had described in a letter to Hevelius. Nevertheless, he wanted to improve his telescopic observations for other tasks, such as mapping the Moon, and asked Oldenburg to obtain the best telescope he could for him, while also making the contradictory demand that it should not be expensive. Oldenburg passed on the task to Hooke, who found a suitable instrument and sent it off to Danzig. This initiated further correspondence between Hevelius and Hooke, with Hevelius insisting that his open sights method was more accurate than Hooke’s telescopic sights observations. Neither man would give way, and there the matter rested for the time being.

  Hooke also corresponded with a young astronomer in Derby, John Flamsteed, who was eager to know how Hooke was able to grind the lenses for his telescopes, and became increasingly frustrated by Hooke’s reluctance to pass on what he regarded as trade secrets. Flamsteed too features later in our story.

  In November 1668, Hooke demonstrated to the Royal an experiment that he had first carried out in October 1666, but which had received little attention in the aftermath of the Fire. It involved three balls of equal weight suspended as pendulums, initially touching one another. When one ball was pulled to one side and allowed to swing down on the other two, it stopped, the middle ball was seemingly unaffected, and the ball on the other side swung up as if completing the pendulum swing of the first ball. Sounds familiar? It was the prototype of the executive toy now known as Newton’s Cradle. It has nothing to do with Newton, but demonstrates Hooke’s discovery ‘that no motion dies, nor is any motion produced anew’, as the Society records put it. Developing these ideas, Hooke was soon able to show that in order for an impact to double the speed of an object moved by an impact, the force on it had to be quadrupled. While Hooke’s terminology is hard to unravel today, he clearly had some idea of the property we now call momentum. And early in 1671 he was studying the way different sounds made patterns in a shallow dish of flour, which he hoped ‘might much contribute to the explication of the nature of the internal motion in bodies’. Meanwhile, during these years, as we have seen, as well as his work as surveyor and architect, he was developing his ideas about, and lecturing on, earthquakes and their implications.

  In the midst of all this, some claims made by an upstart young Fellow of Trinity College, Cambridge, caused Hooke some irritation, fanned into a more serious dispute by Oldenburg’s malicious interference.

  Isaac Newton’s study of light, stimulated by his reading of Hooke’s Micrographia, had led him to the realisation that the passage of white light through a prism or other glass separates the light into its constituent colours. This explained why the images obtained using refracting telescopes were edged with coloured fringes. Although modern telescopes can get round this problem by using compound lenses made of different materials, so that the effect of one part of the lens cancels out the effect of the other, this requires a technology far more advanced than that of the 1660s. Newton realised that the problem would not arise in a reflecting telescope using a curved mirror, rather than a lens, to concentrate the light. The obvious problem with such a device is that in order to see the image in the mirror the observer would have to look down the tube, blocking out the light coming into the instrument.

  Newton found a simple solution to this problem. He put a small flat mirror near the mouth of the telescope tube, tilted at an angle of 45 degrees, so that the focused reflected light from the main mirror bounced off the flat mirror and out through a hole in the side of the tube. The observer could look in through the side of the telescope to see what was overhead. Although Newton did not know it, the idea was not new. Back in the 1550s the English surveyor Leonard Digges came up with essentially the same design as a spin-off from his work with theodolites, but kept it secret so that he would have an advantage over rival surveyors. As far as we can tell, it was based on what is now known as the Newtonian design. Digges probably also invented a refracting telescope, but that is not certain. Nor was Newton the first person thinking about reflecting telescopes in the mid-seventeenth century. The Scot James Gregory had come up with a different design in 1663. In the Gregorian design, the main concave mirror reflects and focuses light on to a smaller concave mirror in the middle of the tube, from where it goes back down through a hole in the centre of the main mirror to the observer.

  Gregory was more of a mathematician than a practical man, so the first telescope using the design was made for him by Richard Reeve, London’s leading instrument maker, in 1664. In spite of Reeve’s skill, the telescope did not prove very satisfactory. Hooke tested it on behalf of the Royal Society, and makes passing mention of reflecting telescopes in Micrographia, but found that he could obtain a sharper image with his reflecting telescopes, even with the irritation of the coloured images, so he gave up any attempt to develop the idea further. Gregory himself left to further his career in Italy.

  Newton’s first telescope was made in 1667 or 1668, shortly after he read Micrographia, but he did not publicise it. This was typical: Newton was a rather odd person, somewhat reclusive, who tended not to bother telling people about his work unless he was prompted to do so.fn8 But by 1671 visitors to Cambridge who had seen the telescope (or possibly a second one made to the same design) had spread news of it as far as London, where the Royal asked to see it. At the end of that year, Newton’s Cambridge colleague Isaac Barrow took the instrument to Gresham College and showed it to the Fellows. They were sufficiently impressed to appoint a committee consisting of Hooke (of course), Wren, Brouncker, Moray and Neile to test it. They found that, although Newton’s telescope was only six inches long, it produced a magnification of thirty-eight times, better than a much larger refractor. On the strength of this, Newton was elected as a Fellow on 11 January 1672, and gave the reflector to the Royal. Newton was twenty-nine, and this was essentially the first time anyone had heard of him; Hooke was thirty-six and established as the greatest scientist in Britain, the ‘go-to man’ of the Royal Society.

  Newton’s arrival on the scene had two effects on Hooke’s scientific life. The first was to revive his interest in reflecting telescopes, no doubt partly in irritation at the adulation Newton had received. In fact, the shine soon went off Newton’s invention – literally. The metal mirror, or speculum, tarnished, and was difficult to keep in shape. By the end of January 1672, Hooke had already started work on what he intended to be a bigger and better reflector, and this continued throughout the year, assisted by one of the London craftsmen, Christopher Cock, but with only limited success. The problems of tarnishing and distortion persisted, even with steel mirrors. And at the same time, Hooke was involved in architectural work, including the College of Physicians, and City work, especially the Fleet Ditch. It wasn’t until March 1673 that the idea Hooke needed was put forward by Gregory in a letter to the Royal. Gregory had the brilliant idea of making the concave speculum out of glass with a mir
rored metal rear surface, so that the shiny metal surface itself would never come into contact with air and would not tarnish. Just under a year later, on 5 February 1674, Hooke presented a telescope based on this idea to the Royal. It was not only the first practical Gregorian telescope, but it was the first practical astronomical reflector, given the problems with Newton’s metal mirror design. And Hooke’s application of Gregory’s idea of a mirrored glass speculum has continued to be used in great astronomical telescopes up to and beyond the Hubble Space Telescope. But by 1674, the other effect of Newton’s emergence from the shadows was beginning to colour Hooke’s scientific life.

  In order to put the feud with Newton in perspective, we need to look first at the mischievous activities of Henry Oldenburg. Like Hooke, Oldenburg had been a member of the Boyle household, having been a tutor to Lady Ranelagh’s son, Richard Jones. He accompanied Richard to Oxford in 1656, and even registered as a student but with no intention of taking a degree. He joined Boyle’s circle of scientific friends in Oxford, but more as an observer and enthusiast than as an active scientist. Although he was not himself a significant scientist, as the first Secretary of the Royal he played a major part in its initial success, and was diligent – sometimes too diligent – about communicating with scientists across Europe. He also founded (in 1665) and published (for its first twelve years) the Philosophical Transactions of the Royal Society, the first scientific journal in the world, which is still going today.