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Finding Longitude

Page 11

by National Maritime Museum


  Fig. 17 – Concluding page from the record of H5’s Kew Observatory trial, by Stephen Demainbray, 1772 (detail)

  {King’s College London}

  William Harrison, however, continued to have the ear of the King, as suggested by a 1773 letter in which he claimed ‘to lay before His Majesty every Tuesday everything which I have done, and I do not write one word or take one step without acquainting him with it’.23 It was thus presumably through the King’s influence that they approached the Prime Minister, Lord North and the Secretary to the Treasury, John Robinson. The Harrisons’ petitions asked for ‘bare justice’. Their long-standing paranoia about Maskelyne remained, and they raised objections to the role that he would play in further tests as he had ‘every Tie of Interest’ and ‘stands pledged to crush the Invention’.24

  A petition was presented to Parliament on 2 April 1773, again blaming the Commissioners and asking for the second £10,000. Meanwhile, William Harrison was asked by the Board of Longitude why he and his father would not make another timekeeper, or consider submitting H5 to trial under ‘two or more persons (to whom you have no objection)’. The Board minutes note his reply as: ‘Loss of time, Expense attending it, Uncertainty of reward afterwards and I think I can employ my time better’.25 The breakdown in relations was complete.

  Harrison’s petition was debated on 27 April. When Lord North outlined the Board’s concerns, the Whig leader, Edmund Burke, replied with a rousing defence of this ‘most ingenious and able mechanic’, who had, ‘according to the verdict of the whole mechanical world, done more than ever was expected’.26 Harrison was, however, advised that the Board had acted legally and so he substituted a new petition that simply called for generosity and assistance. Lord North reported that the King supported this petition and, on 1 July 1773, an Act awarded Harrison a sum not exceeding £8750 for his decades of dedication, ‘as a further Reward & Encouragement over & above the Sum already received by him’.27 This decision took the total amount of money that Harrison had received from government above £20,000 but it also ensured that this payment was less than the £10,000 potentially offered under the 1765 Act.

  Fig. 18 – Medallion portrait of John Harrison by James Tassie, c.1776

  {National Maritime Museum, Greenwich, London}

  Doubt therefore remains, and opinions are divided, over whether it can be said that Harrison had finally won the large reward offered under the 1714 Act. Harrison could stress that, if you added all large and small rewards, he had received at least £20,000 and so the large reward had been paid. However, on other occasions, he also argued that much of this money had been for expenses and that he should still be given the additional £1250 allowed under the 1765 Act. It seems clear that Parliament did not want to be seen to be overruling the decisions of the Board or the legally enshrined conditions of the 1765 Act and, to be sure, £8750 was a very large sum for an expression of the nation’s gratitude for Harrison’s work.

  Many have argued that Harrison should have received £20,000 fair and square after the Barbados trial and before the passing of the game-changing 1765 Act. The Board had chosen to worry about whether or not that trial had shown that Harrison possessed a practicable and useful method that would benefit the public. The question remains: were the Commissioners acting unfairly, being over-conscientious or doing their public duty? Was the ‘Harrison method’ that was on trial simply a single timekeeper that proved capable of doing the job, or was it the means of making a successful marine timekeeper? If the latter, success could only be proved by making more of them.

  The Board of Longitude had, as much as possible, extracted information from Harrison and stepped away from his ongoing complaints. However justified Harrison may have been in his interpretation of the 1714 Act, the Commissioners were concerned about the accountability of their actions and were at the end of their collective tether in dealing with him. Different expectations about the need for openness played their part, although it appears that there were problems communicating with Harrison that did not arise with other clockmakers. Harrison had difficulty expressing himself and his son is widely regarded as having been an unpleasant individual. Their increasing suspicion, together with the Commissioners’ sense that they could now get better results by looking elsewhere, led to the end of a long relationship. Nevertheless, Harrison died a wealthy man on 24 March 1776 (Fig. 18).

  Fig. 19 – Printed lunar-distance form, published by Robert Bishop, 1768

  {National Maritime Museum, Greenwich, London}

  As the Nautical Almanac and timekeepers became, to a greater or lesser extent, more widely available, there was increasing interest in facilitating their use. Getting the new techniques on board at least a few ships, to be used and demonstrated by individuals trained in astronomy and mathematics, was an important initiative. There were also ongoing attempts to develop simplified astronomical and calculating methods, with Maskelyne soliciting and assessing ideas on behalf of the Board of Longitude. One approach was to provide printed forms that guided the user through the calculations and required significantly less mathematical ability (Fig. 19). There was also a recommendation from the Board in 1768 that Masters of Navy ships be required to attend the Royal Naval Academy at Portsmouth or selected London teachers for free instruction in how to use the Almanac and Hadley’s quadrant. It was suggested that their future postings should depend on being able to produce a certificate of attendance.

  The Admiralty acted but it turned out ‘that great difficulties attend the obliging the old Masters of the Navy to perfect themselves in the use of those Almanacs’. They did not take kindly to the idea of compulsory land-based training and only fourteen Masters seem to have undertaken it in the two years following the Board’s suggestion. The Board recommended instead that the Admiralty ‘give such directions as they shall see fit for dispensing with such part of their said orders as related to the old masters and confining the same in future entirely to such new ones only as shall be henceforward appointed’.28

  Despite Harrison’s accusations, the Commissioners do not seem to have expended more energy on promoting astronomical rather than timekeeper methods, although it was understood that the former were more readily available and an essential complement to the early use of timekeepers. They spent large amounts of time and money on making, simplifying and trialling timekeepers. If they were not yet doing more to facilitate their use on board ships, that was because they were still very rare and expensive items.

  Even with the efforts of key Commissioners of Longitude, and the involvement of King and Parliament, it is worth recalling how little impact the debates and decisions of the 1760s and 1770s had on the wider public. Little had yet changed in maritime practice. William Emerson, an eccentric mathematician and inventor who published on navigation, wrote in 1770 that as far as most were concerned the longitude was:

  still a secret, and likely to continue so. For tho’ many thousand pounds have been paid for the pretended discovery thereof; I doubt we shall still remain just as wise as we were before the discovery; except the ill success of it happens to teach us so much wit, as to take better care of our money for the future.29

  CHAPTER 5

  WORKING AT SEA

  We steered for St Helena in a straight line, trusting to our Watch and Lunar Observations.

  John Elliott recalls the Resolution’s homeward track on Cook’s second voyage, 17751

  The Board of Longitude’s work to support the lunar-distance and timekeeper methods was only a part of the story. It was also essential to show that the new techniques could be deployed in any ocean. This meant further trials, training sailors and making better charts. Marine timekeepers remained rare and expensive; it took decades to establish their reliability and for seafarers to trust them. Establishing the use of astronomical techniques, which required mathematical ability and application, was even more of a challenge.

  One arena in which the new methods were trialled was during voyages of exploration. From the 1760s
, the Royal Navy sent out a few special expeditions, most famously those of Captain James Cook (1728–79). These well-funded ventures were a testing ground for the new timekeepers and an opportunity for training mariners. The same was true of expeditions mounted by France, Spain, Russia and other seagoing powers, all international competitors with an equal interest in exploration and economic exploitation. In true Enlightenment spirit, these voyages gathered thousands of artefacts (Fig. 1) and reams of data, including geographical information from the new longitude techniques.

  Fig. 1 – ‘Various articles at Nootka Sound’, by John Webber, showing items collected from the coast of what is now Vancouver Island on the north-west coast of North America during Cook’s third voyage (1776–80)

  {National Maritime Museum, Greenwich, London}

  Proof in the Pacific: the Cook voyages

  Between 1768 and 1779, James Cook (Fig. 2) led three ambitious circumnavigations that would have a lasting impact on European visions of the Pacific. On the first (1768–71), he commanded the Endeavour, which was sent to Tahiti to make observations of a transit of Venus, with additional secret orders to search for a Southern Continent. The second (1772–75), with the Resolution and the Adventure, was to prove whether or not the supposed Southern Continent really existed, while on his third expedition (1776–80), which returned after Cook’s death, the Resolution and the Discovery were to look for a Pacific opening of the long-sought North-West Passage. The voyages were central to the longitude story, since they allowed new instruments and techniques to be tested and applied to navigation and surveying.

  Other than occasional privateering ventures, Britain had shown little interest in the Pacific until the outbreak of war with Spain in 1740, when George Anson was sent there with a small squadron, of which only his Centurion completed the full voyage (see Chapter 3, Figs 9–11). With the publication of Anson’s narrative of his four-year circumnavigation in 1748, the challenges of navigating in unfamiliar waters became clear to all. Importantly, Anson’s account stressed the need for proper surveys to produce accurate charts and prevent future voyages falling victim to the same problems.

  Fig. 2 – Captain James Cook, by Nathaniel Dance, 1775–76. His right hand is pointing at the east coast of Australia on his own chart of the Southern Ocean

  {National Maritime Museum, Greenwich, London, Greenwich Hospital Collection}

  Fig. 3 – ‘Chart of the Island of Otaheite [Tahiti]’ by James Cook, 1769. He established his base for observing the transit of Venus at Point Venus

  {National Maritime Museum, Greenwich, London}

  Anson’s foray was followed up after the end of the Seven Years War with Royal Naval expeditions by the Dolphin in 1764–66 and again in 1766–68, accompanied by the Swallow. On the second of these voyages, the Dolphin discovered Tahiti (Fig. 3), and so determined where Cook’s first expedition would go. This voyage was also one of the first occasions on which a British seaman made a reasonably accurate longitude determination in the Pacific, for the ship’s purser (coincidentally named John Harrison) had the British Mariner’s Guide, an octant and the skills to establish Tahiti’s position. The commander of the ship, Samuel Wallis, said it was done by ‘taking the Distance of the Sun from the Moon and working it according to Dr Masculine’s Method which we did not understand’.2 John Harrison was clearly an unusual purser.

  Cook was sent to Tahiti because it was in the region that Nevil Maskelyne had suggested for observations of the next transit of Venus, due in 1769. From then on, the island became a regular port of call for British vessels and a fixed point at which navigators and astronomers could check their instruments. The Royal Society planned the expedition, with the King’s support, and Maskelyne defined its astronomical purposes and equipment. The choice of Cook as leader was unexpected, but by this time he was an experienced navigator who had shown great skill in conducting surveys and had published solar eclipse observations in the Philosophical Transactions, the Society’s journal. Another notable addition to the Endeavour’s complement was Joseph Banks (1743–1820), who paid his own way as the expedition’s naturalist. In later years, Banks would draw on his experiences with Cook as he became the guiding hand for all British voyages of exploration.

  With the tools and tables developed before the Endeavour sailed in the summer of 1768, the expedition also offered the perfect opportunity to test the lunar-distance method in unknown waters. Astronomical expertise came from Charles Green, appointed by the Royal Society to assist with the observations at Tahiti. Noting as they left England that ‘no person in the ship could either make an observation of the Moon or Calculate one when made’, Green began to put this right.3 Cook himself was using lunars by the time they reached Brazil. As they passed through the waters that had almost defeated Dampier’s and Anson’s ships, the captain had gained confidence in his new-found skills:

  Fig. 4 – Cook’s Resolution in the Marquesas Islands, by William Hodges, 1774

  {National Maritime Museum, Greenwich, London}

  the Longitude of few places in the World are better ascertain’d than that of Strait Le Maire and Cape Horn being determined by several observations of the Sun and Moon, made both by my self and Mr Green the Astronomer.4

  By the end of the voyage, the Nautical Almanac’s value had also become obvious. With only the 1768 and 1769 editions available when the Endeavour sailed, from 1770 Cook and Green had to master the onerous calculations that the Almanac’s tables normally took care of. This extra work aside, Cook was quick to emphasize that

  by [Green’s] Instructions several of the Petty officers can make and Calculate these observations almost as well as himself: it is only by such means that this method of finding the Longitude at Sea can be put into universal practice – a method that we have generally found may be depended upon to within half a degree; which is a degree of accuracy more than Sufficient for all Nautical purposes.5

  This is not to say that Cook depended on the new techniques. Rather, much of the navigation involved traditional methods, notably dead reckoning, and like other commanders before him he recognized the importance of local knowledge. Where possible, he enlisted the help of Polynesians, including Tupaia (c.1725–70), a priest and navigator originally from the island of Ra’iatea (in the western Society Islands). Tupaia joined the Endeavour at Tahiti as a local guide but stayed on board and aided Cook’s negotiations in New Zealand, where the Maori welcomed him as an important religious leader.

  Impressed with the evident success of Polynesian navigation, Cook attempted to learn more from Tupaia, having him draw a chart of the islands around Ra’iatea. Such efforts were part of an ongoing quest to document and understand the peoples they encountered, yet it is clear that Cook never fully understood practices that were not rooted in the coordinates of latitude and longitude, but which relied on a detailed knowledge of environmental features and patterns of change over a huge geographical area. Regrettably, Tupaia was one of those who died of fever later in the voyage.

  Shortly after Cook’s return to England in 1771, plans were afoot for a second voyage in the sloops Resolution (Fig. 4) and Adventure. This time the Board of Longitude was directing the astronomical aspects and appointed William Wales and William Bayly as observers. With new longitude timekeepers now ready, Maskelyne also suggested that the expedition

  Fig. 5 – Captain Cook’s journal on the Resolution, 7 January 1774, showing the longitude determined by lunar distance, timekeeper and dead reckoning (detail)

  {National Maritime Museum, Greenwich, London}

  Fig. 6 – View of Point Venus and Matavai Bay, Tahiti, by William Hodges, 1773, probably sketched from the cabin of the Resolution

  {National Maritime Museum, Greenwich, London, Ministry of Defence Art Collection}

  may be rendered more serviceable to the improvement of Geography & Navigation ... if the ship be furnished with such astronomical Instruments as this Board hath the disposal of or can obtain the use of from the Royal Society and also some of
the Longitude Watches, and, above all, if a proper person could be sent out to make use of those Instruments & teach the Officers on board the ship the method of finding the Longitude ...6

  The ‘Longitude Watches’ were Larcum Kendall’s first marine timekeeper, K1 (Chapter 4, Fig. 11), and three by John Arnold (Chapter 4, Fig. 12), with their testing rigorously controlled much like the tests of H4 and H5. In this case, each watch was enclosed in a box with three locks, with keys held by the commander, first lieutenant and astronomer of the relevant ship, all three of whom were to be present for the daily winding and checking.7 The procedure was generally followed but was not flawless. With Cook and his first lieutenant kept on shore in June 1774, Wales could not open the box and the watch ran down. However, as Cook wrote, ‘This circumstance was of no consequence as Mr Wales had several al[t]itudes of the sun at this place before it went down and also got some after.’8 The watch could be reset from the observations. As well as keeping the watches running, the astronomers had to monitor their performance, checked against dead reckoning, lunar-distance observations and other astronomical observations on land; in other words, they had to compare the results of all available methods for fixing positions (Fig. 5). The Board of Longitude issued instruments including sextants for this work and other equipment for investigations such as magnetic observations (see Fig. 9).

 

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