Finding Longitude
Page 12
The timekeepers were very much at the experimental stage and their performance reflected this. Arnold’s did not do well, perhaps not helped when Bayly forgot to wind one of them. Two stopped during the voyage and the rate of the third increased throughout. By contrast, Kendall’s watch performed superbly, Cook coming to see it as his ‘trusty friend’ and ‘never-failing guide’.9 By the time they reached the Cape of Good Hope on the passage home in 1775, he was a convert. He wrote to the Secretary of the Admiralty that, ‘Mr. Kendalls Watch has exceeded the expectations of its most Zealous advocate and by being now and then corrected by lunar observations has been our faithful guide through all the vicissitudes of climates.’10
Kendall’s timekeeper was no longer on trial. Setting sail for St Helena, Cook put his trust in clockwork rather than opting for the usual practice of latitude sailing. ‘Depending on the goodness of Mr. Kendalls Watch’, he wrote, ‘I resolved to try to make the island by a direct course, it did not deceive us and we made it accordingly on the 15th of May at Day-break’.11 Cook’s words were plain, but confirmed that an otherwise routine leg of the voyage had established the efficacy of a second method for determining longitude at sea.
Fig. 7 – ‘View of Maitavie [Matavai] Bay’, by William Hodges, 1776. The Resolution and Adventure are shown at anchor and a large tent that Cook erected to house his coopers, the guard and sick members of his crew can be seen on Point Venus
{National Maritime Museum, Greenwich, London, Ministry of Defence Art Collection}
Fig. 8 – ‘Part of the Southern Hemisphere shewing the Resolution’s Track through the Pacific and Southern Ocean’, by Joseph Gilbert, c.1775
{UK Hydrographic Office / Photo: National Maritime Museum, Greenwich, London}
Putting longitude to work
Cook’s voyages did not just test the new longitude methods but also began to apply them to navigation and surveying. After all, as Anson highlighted, what use was position-fixing without good charts? The Admiralty’s instructions were explicit on this front. If the Southern Continent was found during the second voyage, Cook was to observe ‘the true situation thereof both in Latitude & Longitude’ and make surveys and charts of any places that might be ‘useful either to Navigation or Commerce’. If there was no large land mass, he was to chart any newly discovered islands.12
Surveying and charting involved almost everyone on board. Directed by the officers, the crews manned the boats engaged in surveying the coasts, carrying out depth sounding and other tasks. The specialists also had their roles. The artists produced visual records of the places visited, either sketched on the spot (Fig. 6) or produced after their return (Fig. 7), and taught the officers to draw better coastal profiles for their charts (Fig. 8). The astronomers were to ‘Settle the position of head Lands, Islands & Harbours in Latitude and Longitude by the cœlestial Observations and also set down what Longitude the Watches give.’13 The new methods came into their own, therefore, for establishing accurate locations that defined the fixed points on which to pin surveys using more traditional techniques and instruments. Thus, on the third voyage, Cook noted that the Aleutian Islands in the northern Pacific were now free of the errors found in Russian charts,
as the most of the islands were seen by us, consequently their latitude and longitude pretty exactly determined, particularly the harbour of Samgoonoodha in Oon[a]laska which must be looked upon as a fixed point.14
His certainty came from having used thirty-four sets of lunar observations to establish its position.
Fixing geographical locations accurately was a lengthy process, since the best observations could only be made when there was time to erect an observatory for the larger clocks and telescopes (Fig. 9). The stability of land did, though, mean that the astronomers could carry out observations that were impossible at sea, including observations of Jupiter’s satellites in order to fix longitudes. It was also an opportunity to check the watches against the observatory instruments. However, being able to fix longitude from a ship meant that the large instruments, though more accurate, were not the only means of fixing positions with some certainty. As Lieutenant James King noted during the third voyage,
Fig. 9 – Draft list of the instruments to be supplied to the astronomers on Cook’s third voyage, by Nevil Maskelyne, dated 22 May 1776
{Science Museum / Science & Society Picture Library}
on the coast of America and Asia greater care was taken to find the difference between Longitudes by Lunar obsns & by T.K. [timekeeper], these comparisons were made at Sandwich Sound, to the N of Cape Newenham & in Norton Sound, from whence I should suppose the ... Lunar observations on these coasts to be nearly the true situation of the ship in Longitude.15
In addition, lunar-distance and timekeeper methods were used both to check and supplement each other. During the second voyage, Cook found that they ‘did not differ from each other two miles’.16 On the third voyage, the longitude of Ship Cove in Nootka Sound was settled by 134 sets of lunars, ninety of them taken at the temporary observatory (Fig. 10), the remainder taken from the ship and corrected to the same position with the help of the timekeepers. The new, portable techniques could also fix the positions of places that would otherwise remain unknown: ‘Even the situation of such islands as we past without touching at are by means of Mr Kendalls Watch determined with almost equal accuracy’, Cook wrote in November 1774.17
Yet there was a hierarchy: astronomical determinations were considered more certain than those from mechanical timekeepers alone. In the later parts of the third voyage, the astronomical observations took on particular importance as the timekeepers began to cause concern. By 1779, K1’s performance was ‘so irregular that I fear very little dependence is to be put upon it’.18 Finally it stopped and, though restarted, worked poorly for the rest of the voyage. The ships relied instead on Kendall’s third timekeeper, K3, although it never performed as well as K1.
Fig. 10 – ‘Resolution and Discovery in Ship Cove, Nootka Sound’, by John Webber, 1778. Just to the right of the centre can be seen the astronomers’ observing tents
{National Maritime Museum, Greenwich, London}
Astronomical methods were not perfect, though. Cook realized on the second voyage that, during the first, his and Green’s observations had placed much of the South Island of New Zealand (Fig. 11) too far east. Likewise, on the third voyage, Lieutenant King worried about ‘the extream errors in different peoples observing with different sextants’, which might undermine confidence in the lunar-distance method.19 He explained that the errors came from lack of practice and the swapping of sextants (Fig. 12) between the young officers.
King’s concerns highlighted another important role for the voyages: training officers in longitude techniques. This had a longer-term legacy that was crucial for embedding astronomical and timekeeper methods within naval practice. From the second voyage onwards, the astronomers were to ‘teach such of the Officers on board the sloop as may desire it the use of the Astronomical Instruments & the Method of finding the Longitude at sea from the Lunar Observations.’20 Cook was optimistic about this: ‘any man with proper applycation and a little practice’ could learn the techniques if enough instruments and astronomical tables were supplied.21 King agreed, although the abilities of these two mathematically adept officers probably blinded them to the difficulties others had with the calculations for lunar-distance and local time. This is borne out by an anecdote from 1781, when King was commanding a convoy to the West Indies. According to his first lieutenant, he chose to use lunars to make a direct course to Barbados, to the consternation of the ships being escorted:
Fig. 11 – Chart of New Zealand, by James Cook, 1772. On the second voyage, Cook discovered errors in some of the longitudes determined during the first
{National Maritime Museum, Greenwich, London}
Fig. 12 – Sextant, by Ramsden, London, c.1772, used on Cook’s third voyage
{National Maritime Museum, Greenwich, London}
Nothing could exceed the surprise and terror of the masters of the merchant ships who, used only to the old jogtrot of their ancestors, were soon bewildered and lost all kind of tolerable accuracy in their reckoning. But when they found that the skill of the circumnavigators had brought them exactly to the desired point, nothing could exceed their admiration and astonishment.22
Cook, King and others showed that astronomical methods and timekeepers could be successfully deployed for navigation and surveying, and that the skills required could be passed on, but there was still some way to go before the methods would be commonplace.
In Cook’s wake
James Cook’s death during a skirmish at Kealakekua Bay in Hawaii on 14 February 1779 added to an already heroic reputation. To the leaders of later voyages, he became the archetypal explorer, although as Georg Forster, naturalist on the second voyage, wrote, ‘there are no large discoveries left to make because now the globe is known from one end to the other.’23 Nonetheless, the three voyages established the template for future expeditions by the inclusion of specialist astronomers, naturalists and artists. Later voyages also sought to exploit the discoveries Cook’s expeditions had made of valuable products such as timber, flax, whales, seals and sea otters (Fig. 13), as well as new trading goods. Yet while the promise of lucrative trade drove many of the voyages, state-sponsored expeditions continued to lead the way in the development, testing and application of the new longitude methods at sea and on land.
Fig. 13 – ‘A Sea Otter’, by John Webber, artist on Cook’s third voyage
{National Maritime Museum, Greenwich, London}
The expense and rarity of the new instruments, particularly marine timekeepers, meant that they were available only to vessels that were well supported by the state or to individuals with cash to spare. As a result, specific instruments might serve several different voyages during their working life. Kendall’s first marine timekeeper (K1), for instance, stayed in service beyond Cook’s second and third voyages. Although it had stopped after Cook’s death, Kendall was able to repair it and in 1786 the watch was passed to Captain Arthur Philip, sent out in the Sirius in command of the First Fleet to establish a colony in Australia. This was a very different type of voyage to Cook’s but its status was high. The timekeeper was nearly lost when the Sirius was wrecked on Norfolk Island in March 1790 but, luckily, it was safely taken off before the ship sank. After returning to England, K1 was sent with John Jervis to the West Indies at the start of the French Revolutionary War, where it was presumably involved in operations, before being returned and withdrawn from service in 1802.
Kendall’s second marine timekeeper, K2 (Fig. 14), had an even more turbulent history. Its first major naval expedition was on the Racehorse, commanded by Captain Constantine Phipps in a voyage towards the North Pole in 1773. Its most infamous years, however, came after it joined the Bounty in 1787. As Lieutenant William Bligh (1754–1817) later noted:
Fig. 14 – Marine timekeeper K2, by Larcum Kendall, London, 1771
{National Maritime Museum, Greenwich, London}
Fig. 15 – A branch of the breadfruit tree, from John Hawkesworth, An Account of the Voyages Undertaken ... in the Southern Hemisphere (London, 1773)
{National Maritime Museum, Greenwich, London}
The Object of all former voyages to the South Seas, undertaken by command of the present majesty, has been the advancement of science, and the increase of knowledge. This voyage may be reckoned the first, the intention of which has been to derive benefit from these distant discoveries.24
The aim of the voyage was to transplant breadfruit (Fig. 15) from Tahiti to the West Indies as food for the slaves forced to work the plantations there. This would benefit the plantation owners and thus Britain’s expanding trade and imperial aspirations, and it was heavily promoted by Joseph Banks, a man of considerable influence after becoming President of the Royal Society in 1779. Banks understood the plant’s potential from his time with Cook in Tahiti, where it grew in abundance. By 1787, he had convinced the government to support the expedition and then oversaw its planning, including the choice of ship and its conversion to accommodate breadfruit plants, as well as the selection of Bligh, a fine navigator who had sailed with Cook, as commander. Although the expedition was not primarily scientific, its status and Banks’s sponsorship persuaded the Board of Longitude to lend Kendall’s second timekeeper, a few other instruments and copies of the Nautical Almanac.
The voyage has since become notorious because of the events that culminated on 28 April 1789 with Fletcher Christian leading a mutiny and setting Bligh and eighteen others adrift in the ship’s launch (Fig. 16). The mutineers recognized the value of K2 and other navigational paraphernalia. As the men being cast adrift collected supplies, Bligh recalled,
Fig. 16 – ‘The Mutineers turning Lt Bligh and part of the officers and crew adrift’, by Robert Dodd, 1790
{National Maritime Museum, Greenwich, London}
Mr. Samuel [the Clerk] ... got a quadrant [octant] and compass into the boat; but was forbidden, on pain of death, to touch either map, ephemeris, book of astronomical observations, sextant, time-keeper, or any of my surveys or drawings.25
Bligh nevertheless managed to guide the twenty-three foot launch more than 3500 nautical miles to the Dutch settlement on Timor. Although he had neither charts nor timekeeper, he did have a sextant by Jesse Ramsden, an octant, a compass, a log line made from what was to hand in the launch and two navigation books, Hamilton Moore’s Practical Navigator and Dunthorne and Maskelyne’s Tables Requisite. This was enough for latitude observations and dead reckoning, although Bligh played up his navigational skills by later omitting to mention that he had the sextant and Hamilton Moore’s book. Nonetheless, the boat’s successful arrival in Timor was testament to the value of older techniques when deployed by a skilled navigator. Equally impressive was Bligh’s ability to maintain the crew’s morale and eke out their meagre rations.
Meanwhile, Kendall’s watch remained on the Bounty, although whether it was much used is uncertain. Christian had some navigational knowledge, which presumably helped him choose their final destination of Pitcairn Island. This had been sighted ‘like a great rock rising out of the sea’ by Philip Carteret on the Swallow in the 1760s. Carteret believed that, though tricky, a landing would be possible and noted trees and running water, but his recorded longitude was wrong by three degrees.26 As a result, even Cook was unable to find it. Christian must have realized that the island would make a safe haven from any ships sent after the mutineers. His thinking was sound: they arrived on Pitcairn in 1789 and K2 remained undisturbed until an American whaling captain discovered their refuge in 1806 and purchased it from John Adams, the last Bounty survivor. After passing through several hands and being stolen at least once, the watch arrived back in Britain in the 1840s.
The Board of Longitude supplied instruments to voyages of exploration because they wanted them tested, ideally under the supervision of observers they had employed. Two later voyages show how the Navy’s own navigators also began to adapt to the challenges of deploying the new instruments and techniques at sea. Above all, they demonstrate increasing interest from the Navy in adopting promising longitude methods, in particular from officers who had been introduced to them during their time with Cook.
Fig. 17 – Marine timekeeper K3, by Larcum Kendall, London, completed in 1774, showing the timekeeper, its mechanism and the timekeeper in its box.
{National Maritime Museum, Greenwich, London, Ministry of Defence Art Collection}
Fig. 18 – ‘A Chart showing part of the Coast of N.W. America’, drawn by George Vancouver, published by Robinson and Edwards, 1798
{National Maritime Museum, Greenwich, London}
In 1791, Captain George Vancouver was sent to chart the north-west coast of America, to search for a North-West Passage and to resolve tensions with the Spanish following the recent Nootka Sound Crisis. It was a naval expedition, so it was the Navy Board that supplied the i
nstruments, although these were similar to the equipment typically provided by the Board of Longitude. The Board did, however, supply two timekeepers: Kendall’s third, K3 (Fig. 17), for the Discovery – a new ship of that name – and an Arnold for the Chatham. As a veteran of Cook’s second and third voyages, Vancouver was familiar with longitude-finding techniques and could be trusted with the valuable equipment. Indeed, he was delighted with K3, ‘the excellence of which’, he wrote, ‘had been manifested on board the [old] Discovery during Captain Cook’s last voyage, and which had lately been cleaned and put into order by its very worthy and ingenious maker’.27
Vancouver was an enthusiast for lunar distances too and took advantage of the outward journey to test the equipment to hand. He tried out no less than twelve sextants and found that they ‘agreed exceedingly well together’. Later, having observed ‘many very good lunar distances of the sun and stars on different sides of the moon’, he took their average to be the ‘true longitude’ and so judged the timekeeper’s longitude to be 14´ 25˝ too far east. Again, a hierarchy was clear in the perceptions of the different methods. Vancouver was keen to teach his junior officers as well, anticipating a time ‘when every sea-fearing person capable of using a quadrant, will, on due instruction, be enabled by lunar observations to determine his longitude at sea.’28 As he noted of the Discovery,
on our departure from England, Mr. Whidbey [the ship’s master] and myself could be considered as the only proficients in this branch of science; but now, amongst the officers and gentlemen of the quarter deck, there were several capable of ascertaining their situation in the ocean, with every degree of accuracy necessary for all the important purposes of navigation.29