Out of the Shadow of a Giant

by John Gribbin

  ‘Is. Newton’

  There are, though, grounds for suspicion about just how friendly Newton was being. The sentence ‘If I have seen farther, it is by standing on the shoulders of giants’ is at first sight a repetition of a classical example of false modesty dating back at least to first-century Rome. Newton was well aware of Hooke’s small physical stature, and at the very least it was tactless to include the words; at worst, some historians have argued, it was a deliberate insult, implying ‘I have no need to steal ideas from a little runt like you’. And it is certainly not genuine modesty! Intentional or not, it is highly likely that Hooke, who was sensitive about his size, would have taken it as an insult.

  After this exchange, Newton went back into his shell, and Hooke was busy with architectural work. But around this time two aspects of Hooke’s life came into conjunction, when his architectural work brought him into contact with a young man who would become a friend for life, and would be instrumental in elevating Newton to the status of a giant in whose shadow they lived.

  In March 1675, Charles II appointed John Flamsteed as his ‘astronomical observator’, a term soon replaced by the title Astronomer Royal, which we shall use throughout. This wasn’t just a result of the King’s rather dilettante interest in science, but related to the importance of navigation: the Astronomer Royal’s main task, at first, was to carry out a survey of the northern skies, mapping the positions of the stars using telescopic sights, to improve upon the survey made by Tycho Brake in the sixteenth century using open sights. At first Flamsteed was an ‘observator’ without an observatory, but something was already being done about that.

  Hooke was closely involved in all this. He was in correspondence with Hevelius about the relative merits of open sights and telescopic sights, and he had developed the best astronomical surveying instruments in England, possibly in the world. It was the success of Hooke’s instruments that persuaded Charles that it would be worth the expense of building an observatory, and in September 1674 Hooke and Sir Jonas More (or Moore), who was Surveyor-General of the Ordnance and a good friend of Hooke, were sent to assess the suitability of a former theological college in Chelsea as a home for the observatory. Moore offered to contribute £250 to the cost if the project went ahead. When Flamsteed heard about the project, he began lobbying for the job of running the observatory, buttering up Moore in a series of letters. At first, these included criticism of Hooke (whom Flamsteed saw as a rival for the post) for his secrecy, but when he realised the relationship between Hooke and Moore was friendly, he changed his tune. Flamsteed sent Hooke the present of a firkin of ale, and wrote to Moore ‘for the futur my opinion of him shall be much more charitable.’ The lobbying worked, and it was largely on Moore’s recommendation, with the acquiescence of Hooke, that Flamsteed became the first Astronomer Royal.

  Within a week of Flamsteed’s appointment, at the end of March 1675 he received a letter from an eighteen-year-old Oxford undergraduate, Edmond Halley, describing some of his own observations, which disagreed with published tables of data, and asking Flamsteed’s advice. It turned out that Halley was right and the tables were wrong; by the summer, Halley was acting as Flamsteed’s unpaid assistant on visits to London. But those visits did not involve the old theological college in Chelsea.

  A committee that included Hooke and Wren decided that the best site for the observatory would be at Greenwich, and that it should be an independent institution, not under the auspices of the Royal Society. On 22 June, the Royal Warrant, which established the Royal Greenwich Observatory, was issued. It begins:

  Whereas, in order to the finding out of the longitude of places for perfecting navigation and astronomy, we have resolved to build a small observatory within our park at Greenwich, upon the highest ground, at or near the place where the castle stood, with lodging rooms for our astronomical observator and assistant, Our Will and Pleasure is that according to such plot and design as shall be given you by our trusty and well-beloved Sir Christopher Wren, Knight, our surveyor-general of the place and site of the said observatory, you cause the same to be built and finished with all convenient speed.

  So Wren, or rather, Wren’s firm, was in charge of the design and construction of the observatory. This meant a significant role for Hooke the architect, as well as his input of scientific expertise, and the donation of some of his instruments and designs for others for the observatory. Wren appointed Hooke as site manager, ‘to direct [the] Observatory in Greenwich Park for Sir J More’, who was the King’s representative. There is no detailed record of Hooke’s contribution, but it clearly was substantial: on 28 July 1675 his diary records that he ‘set out’ the observatory (that is, marked the building lines out on the ground) in accordance with the architectural drawings, but we do not know if it was Wren, or Hooke, or both of them together, who made those drawings. Whoever was responsible, the building went up with impressive speed, and the observatory was essentially complete (at a cost of just over £520) by June 1676, when it was used to view an eclipse. The diary also records visits by Hooke to Greenwich in the company of Flamsteed and Halley, although we have no record of the exact date on which Hooke and Halley first met. It would be Halley, not Hooke, who played a major part in the scientific development of the Royal Greenwich Observatory, and who would become the second Astronomer Royal. It is time to fill in the background of this nineteen-year-old prodigy.

  CHAPTER FIVE

  FROM HACKNEY TO THE HIGH SEAS

  According to Samuel Pepys, ‘Mr Hawley – May he not be said to have the most, if not to be the first Englishman (and possibly any other) that had so much, or (it might be said) any competent degree (meeting in them) of the science and practice (both) of navigation. And the inferences to be raised therefrom.’ This passage is doubly revealing. First, thanks to the flexibility of spelling in seventeenth-century England, it shows us how to pronounce Edmond Halley’s surname – for the first syllable to rhyme with ‘trawl’, or ‘crawl’.fn1 Second, it indicates the breadth of Halley’s interests and skills. He is most widely known today as an astronomer, but here Pepys is praising his ability as a navigator, not just an expert in the theory of navigation, but as a practical seafaring explorer. There is much more to Edmond Halley than you might think, if you only know him because of the comet that now bears his name.

  We are particularly grateful to diarists such as Pepys, Hooke and Aubrey for the occasional glimpses they give us into Halley’s life, because he kept no diary himself, and details of his personal life are scarce. We are not even absolutely sure when he was born, although the accepted date is 29 October 1656 (OS). Although Halley himself gave this date, doubts have arisen because although there is no surviving record of his birth, there is a record of the marriage of his parents, Edmond Halley senior and Anne Robinson, just seven weeks earlier than the accepted birth date. One suggestion is that the year of Halley’s birth should be 1657, not 1656; a more likely possibility is that his parents had a civil marriage earlier, at the height of the Protectorate, and a church wedding some time afterwards. This is of no real importance, except that it demonstrates the difficulty of finding out even the basics about Halley’s personal life.

  At least we know something about his father, because Edmond Halley senior was a successful businessman who left his mark in the official records. His businesses involved the manufacture of soap and salting, an essential means of preserving food in those days, and he also owned property in London (that is, within the City itself) that brought in about £1,000 a year in income at the time young Edmond was born. As far as it is possible to make comparisons, that would be well over £100,000 today. As well as the properties that he rented out, Halley senior owned a house in Winchester Street, long since cleared to make way for railway lines running into Broad Street station, and a house at Haggerston, three miles to the north-east of St Paul’s Cathedral. In 1656 this was countryside, part of the borough of Hackney. Edmond junior was born in the country house, but the family moved between the tw
o residences. He had a sister, Katherine, who was born in 1658 and died as an infant, and a brother, Humphrey, whose birth date is not known, but who died in 1684. Anne Halley died in 1672, but the circumstances are not known. Unlike Hooke, Halley was not affected by the turmoil of the Protectorate and the Restoration of Charles II, which took place in 1660, when he was three.

  A rare glimpse of the young Halley comes from Aubrey, who tells us that when the boy was about nine years old he was taught to write and do ‘arithmetique’ by an apprentice of his father. This might have been during the plague year of 1665, when presumably the family stayed in the comparative safety of their country home.

  The following year, the fortunes of the Halley family were hit by the great fire, which destroyed a large part of Edmond senior’s investment portfolio. But he weathered the storm, and when London was rebuilt he was able to charge higher rents for the improved buildings – an early link between Hooke and the Halley family. The salting business also prospered through the expansion of the navy under Charles II (and his able administrator Samuel Pepys), since salt meat was the staple diet in ships.

  Very little is known about Halley’s early education. He attended St Paul’s School, but we are not sure when he started there. We do know that he was made School Captain in 1671, a year before Thomas Gale became headmaster, or High Master as he was officially titled. Gale, a distinguished scholar who had previously been in charge of Greek studies in Oxford, would play an important part in Halley’s later career. He was an expert mathematician, and must have stimulated Halley’s efforts in that direction, before the young man, encouraged by Gale, went up to Oxford in 1673, the year he was seventeen. If we are to believe Halley’s contemporary Anthony Wood,fn2 he arrived in Oxford with a glowing reputation:

  He not only excelled in every branch of classical learning, but was particularly taken notice of for the extraordinary advances he made at the same time in the Mathematicks. In so much, that he seems not only to have acquired almost a masterly skill in both plane and spherical Trigonometry, but to be well acquainted with the science of Navigation, and to have made great progress in Astronomy before he was removed to Oxford.

  This should perhaps be taken with a pinch of salt, since it was written long after the event, when Halley was already famous. But it is certainly true that Halley arrived in Oxford not just with a reputation as an astronomer but also armed with astronomical telescopes and other equipment that would have been the envy of just about any professional astronomer of the day. His own later account, in the introduction to his Catalogue of Southern Stars, says that ‘from my tenderest youth I gave myself over to the consideration of astronomy’, while the study of science gave ‘so much pleasure as is impossible to explain to anyone who has not experienced it.’ And ‘I soon realized that it is not from books one should try to advance this Art [astronomy], but that one ought to have recourse to instruments for measuring …’ He was lucky to have a father able and willing to provide him with the finest astronomical instruments, and clearly would not be the kind of dilettante Oxford undergraduate who enjoyed the high life, rarely attended lectures, and left without a degree. Although, as it happens, he did leave without a degree.

  Halley entered Queen’s College on 24 July 1673 as a commoner. This was, as the name suggests, the most common kind of undergraduate. ‘Upper commoners’ were the sons of nobility or wealthy gentlemen, and rarely took degrees. Commoners were the sons of gentlemen of a slightly lower status, and about half of them took their degrees with a view to becoming ordained. There were also subsizars (like Isaac Newton in Cambridge, and as Hooke had been, at least on paper) who earned their place by acting as servants for the wealthy students. Halley must have studied Latin and Greek, as well as mathematics, and on his own initiative he observed the heavens with his instruments, which included a telescope twenty-four feet long and a large quadrant. He learned geometry from John Wallis, one of the ablest mathematicians of the time and a founder member of the Royal Society, and astronomy from Edward Bernard, a former student of Wallis. Bernard had learned Arabic in order to study the Islamic texts that had preserved the astronomical knowledge of the Ancient Greeks, and Halley picked up enough for him to be able to study the Arabic texts himself.

  While he was in Oxford, and also when at the Winchester Street house during vacations, Halley had been making astronomical observations in the company of Charles Bouchar, a slightly older student. Bouchar had been corresponding with the astronomer John Flamsteed, but left for Jamaica on family business early in 1675. So on 10 March that year Halley picked up the correspondence, writing to Flamsteed to explain why Bouchar had not replied to Flamsteed’s latest letter, and describing his own observations. This was just a week after Flamsteed had been appointed as the first Astronomer Royal by Charles II. The most important content of the letter was that Halley had found that the positions of Jupiter and Saturn that he had observed differed significantly from the predicted positions published in tables based on calculations of their orbits. He asked if Flamsteed had ‘observed anything of the like nature’ and requested that, if so, ‘I beg you would communicate it’.

  Halley had also observed a lunar eclipse, this time from Winchester Street, on 1 January 1675. Once again, the timing of this event did not match published predictions, and once again he asks Flamsteed to confirm that he too noticed the discrepancy, And then, with great chutzpah, he says that he ‘thinks fit to signifie’ that he has found errors in some of the positions of stars recorded in the catalogue of Tycho Brahe, the great astronomer who had surveyed the northern skies in the 1590s. He sums up:

  These Sr. as a specimen of my Astronomical endeavours I send you, being ambitious of the honour of being known to you, of which if you shall deem me worthy I shall account my self exceedingly happy in the enjoyment of the acquaintance of so illustrious and deserving a person as yourself.

  He was still only eighteen; Flamsteed himself not quite twenty-nine.

  Flamsteed was suitably impressed with Halley’s ability and enthusiasm, and in the summer of 1675 they made observations together from London, and were often seen chatting together in coffee houses. Flamsteed mentioned Halley in a letter to the German astronomer Johannes Hevelius, and wrote in the Philosophical Transactions that ‘Edmond Halley, a talented young man of Oxford, was present at these observations and assisted carefully with many of them.’ As we have seen, Halley also accompanied Hooke and others on visits to Greenwich to plan the building of the Royal Observatory. Flamsteed moved to Greenwich in July 1675, and began observing from the site in September; Halley was back in Oxford by then, but continued to send Flamsteed his observations. With Flamsteed’s encouragement, he produced three scientific papers in what turned out to be his last year in Oxford as an undergraduate.

  The first was a theoretical paper, which demonstrates Halley’s ability as a mathematician. He devised a geometrical technique to calculate the orbits of the planets using observations from the Earth, which, of course, is itself moving. This is by no means a trivial problem, and the paper helped to establish Halley’s reputation. The second paper Halley was involved in was actually written by Flamsteed, and described their independent observations of dark spots that appeared on the surface of the Sun in July and August 1676. These spots were particularly noteworthy at the time, because sunspots were very rare in the second half of the seventeenth century; we now know that the Sun was in an unusually low state of activity at that time, which may have been linked to the cold of the so-called Little Ice Age that gripped Europe for decades. The third paper compared observations of an occultation of Mars by the Moon (when the Moon passes in front of Mars) made by Halley in Oxford, Hevelius in Danzig, and Flamsteed at Greenwich. In the same year, Halley devised, but did not publish, a technique to predict exactly where the Moon’s shadow will pass over the surface of the Earth during a solar eclipse; Flamsteed later discussed Halley’s idea in his book Doctrine of the Sphere, published in 1681.

  By the autumn of 1676,
Halley had completed three years as an undergraduate. In those days, it was usual (for those actually taking a degree) to spend four years in residence before graduating. But Halley had other ideas, which had been brewing in his mind for some time. One of Flamsteed’s principal tasks as Astronomer Royal was to make a new survey of the heavens, improving on Tycho’s survey not least because, unlike Tycho, he had telescopic sights to work with. This was all well and good, but what about the southern hemisphere? As Halley, and others, appreciated, it was high time for a survey of the southern skies, both out of scientific interest and in order to provide aid to navigation as ships ventured south of the equator. Halley was sure he was the right man for the job, and was too impatient to wait until he graduated to do it. Besides, someone else might pre-empt him if he delayed. After consultation with Flamsteed, he settled on the island of St Helena, the most southerly piece of land then held by the English, as the site for his observations. He was encouraged in this choice by what turned out to be misleading reports that the weather there was good and he would have clear skies for his observations.

  As early as July 1676 Halley wrote to Oldenburg at the Royal, announcing this plan and presumably hoping for some sort of formal endorsement from the Society. He didn’t succeed in getting an official endorsement, but Oldenburg joined Flamsteed in wiring a statement pointing out the value of the project, which Halley was able to use in an approach to the King for permission to go ahead. St Helena was governed by the East India Company, and one of its directors just happened to be Robert Boyle. The company had an original charter from Elizabeth I, reinforced by charters from Charles II, which essentially gave it a free hand to trade in the English interest, especially in India. It ran its affairs like a government, with its own ships and armed forces, governing territories like St Helena. But they were still subjects of the Crown, and had to take notice when they received a letter from the King ‘recommending’: