As a petition put to Parliament in Harrison’s name back in 1762 had suggested, a ‘discovery’ of the watch should be made ‘in such manner as that other workmen may be able to Execute the same so that it may in a short time become serviceable to this Kingdom and to all who use the Sea’.9 Yet Harrison still hoped that he could be paid the full £20,000 and retain a monopoly on future manufacture. He told the Board that they could either give him £800 to make two more watches that would let him claim the second £10,000, or they could advance it and allow him to set up a factory and employ and train other workmen. The Board refused both options.
The disclosure of the mechanism of Harrison’s fourth longitude timekeeper, H4 (Fig. 9 and Chapter 3, Fig. 17), was to be witnessed by a reappointed Commission for the Discovery of Mr Harrison’s Watch, overseen by Maskelyne. These were experts whom the Admiralty could trust and individuals who might understand and reproduce the mechanism: mathematicians John Mitchell and William Ludlam; instrument maker John Bird; and watchmakers Thomas Mudge, William Matthews and Larcum Kendall. The ‘full discovery’ was to include explanation of the tools used, details of the methods of tempering the metals, and spoken, written and drawn descriptions of the mechanism. The Commissioners were aware of their responsibility to follow the description well enough to be able to report and, perhaps, make such a watch themselves.
Fig. 10 – Drawings from The Principles of Mr. Harrison’s Timekeeper (London, 1767)
{National Maritime Museum, Greenwich, London}
Fig. 11 – Marine timekeeper K1, by Larcum Kendall, 1769
{National Maritime Museum, Greenwich, London, Ministry of Defence Art Collection}
The disclosure took place in August 1765 at Harrison’s house and workshop in Red Lion Square. After six days of explanation and demonstration, the Commissioners declared themselves satisfied. Interestingly, though, four of the six – Ludlam, Mitchell, Kendall and Bird – would later express doubts over the adequacy of the explanation or the practicality of the watch. Ludlam suggested in print that the methods were not readily transferable, that the disclosure was incomplete, that Harrison had made adjustments by trial and error rather than by following a method, and that the watch’s temperature adjustment was inadequate.
Harrison handed his timekeepers over to the Admiralty, much against his will but as a long-standing condition of the rewards he had received so far. They would be taken to Greenwich for further trials – the beginning of the Observatory’s enduring role as a place for trialling, storing and checking marine timekeepers. In 1766, H4 was subjected to a ten-month trial against the Observatory’s astronomical regulator. The watch was wound daily, usually by Maskelyne, sometimes by his assistant, but always in the presence of an officer of Greenwich Hospital, where the key for one of the two locks on the box was kept.
Fig. 12 – Marine timekeepers, by John Arnold, c.1771
{The Royal Society}
It did not perform well over this period as a whole, with its rate (the amount of time it gained or lost each day) appearing erratic. The trial appeared to show that, statistically, H4 was likely, but not certain, to perform successfully over the course of a six-week voyage. It also suggested that the corrections made to compensate for its rate would have to be frequently adjusted over the course of a longer voyage, especially in cold weather, making the watch less generally practical. Maskelyne found that it ‘cannot be depended upon’ to keep the longitude within a degree on a voyage to the West Indies, nor to keep it within half a degree for more than a fortnight, and it could be much worse if conditions were unfavourable. Nevertheless, he concluded that it would be ‘a useful and valuable invention’ that, used ‘in conjunction’ with lunars to check whether and by how much its rate changed over the course of the voyage, ‘may be of considerable advantage to navigation’.10
Fig. 13 – Horloge marine no. 8, by Ferdinand Berthoud, 1767
{Musée des arts et métiers - CNAM, Paris / Photo: S. Pelly}
Harrison attacked Maskelyne’s integrity in the conduct of the trial, his care of the timekeepers and his claims for lunar distances, accusing him of being ‘deeply interested’ in the lunar scheme. The clockmaker emphasized that, if the rate of the watch was regularly recalculated and compensated for, any six-week period of the trial, save those in extreme cold or where the watch had not been kept horizontal, would yield a result that was within the limits of the 1714 Act. Maskelyne did not disagree but this did not answer the greater question of whether the watch had solved the problem more generally: could it be used on longer voyages and in extreme conditions? Could another be made?
Harrison was, in the meantime, making a second watch but continued to complain about his treatment and about having to work under the new Act. His viewpoint was irreconcilable with that of the Commissioners. Ultimately he bypassed the Board and turned to Parliament and George III. The Board of Longitude also looked elsewhere. This did not mean they were prejudiced against or disbelieving of timekeepers as a viable means of finding longitude. Their investment in Harrison had been huge and they were not interested in letting it prove a dead end.
Making more timekeepers
As Maskelyne informed his brother in 1766, shortly after the arrival of H4 at the Observatory,
The board of longitude are also desirous to encourage the making of watches after Mr. Harrison’s method. They have engaged a person to make one. I have had the drawings engraved here under my eye, & shall publish them in a short space of time.11
The person engaged was Larcum Kendall (1719–1790), whom William Ludlam believed was ‘more likely to make such a Watch than any body of the Trade that he knows of’.12 Kendall had been apprenticed to John Jefferys and may have helped make some parts of H4, as well as having been present at its disclosure. He proposed to make a replica in two years for £450. It would be as identical as possible, ‘But I will not be answerable for its keeping time’.13 This proviso was inserted on Ludlam’s private suggestion that he make no guarantees that it would perform as Harrison’s had: ‘it might be good fortune in that case, & the thing never happen again’.14
The Commissioners did not, however, wish to rely only on Harrison and Kendall. Early on, Kendall had been instructed to let not only the Harrisons see H4, if required, but also any other ‘ingenious persons’ who expressed an interest.15 Another essential means of disseminating Harrison’s ideas was the publication of his drawings and descriptions in the 1767 Principles of Mr. Harrison’s Timekeeper (Fig. 10), edited by Maskelyne. Five hundred copies were printed, with translations into French and Danish appearing with astonishing speed. It was hoped that this would spark imitation and innovation in the design of timekeepers. The Board, therefore, continued to offer rewards for improved timekeepers, as well as other methods.
Fig. 14 – The balance assembly of Pierre Le Roy’s montre marine (marine watch) in Le Tellier, Journal du Voyage de M. le Marquis de Courtanvaux (Paris, 1768). The assembly incorporated temperature compensation with two adjustable balance springs below
{National Maritime Museum, Greenwich, London}
Kendall completed his copy of Harrison’s watch, today known as K1 (Fig. 11), and presented it to the Board on 13 January 1770. It was pronounced a faithful copy and Kendall was given both the £450 and a further reward of £50. He was asked to take on the task of instructing other workmen to make the necessary parts for further copies. On 26 May 1770, however, he demurred. There were ‘so many difficultys’ in the undertaking, he said, ‘I am well assured in my own mind; I shall not be able to do the publick any service’.16
What the Board wanted, Kendall understood, was a means by which ‘a Watch might in a short time be made for a reasonable price’. His view was that ‘it would be many years (if ever) before a watch of the same kind, with that of Mr Harrisons; could be afforded for Two hundred Pounds’. He explained that making more replicas would:
never answer [the Board’s ends] so effectually; as to make the watch become of publick utility. for unles
s a reduction; of the expensive parts of the Watch can be effected; & some method contrived, to facilitate the adjusting; the watch would still come to so high a price; as to put it far out of the reach of purchase for general use.17
Fig. 15 – Marine timekeeper, by William Snellen, c.1775, and probably influenced by Harrison’s work
{National Maritime Museum, Greenwich, London}
Kendall told the Board that, instead of producing another copy, changes to Harrison’s design might allow him to make a watch that was just as good but less than half the price. This watch, K2 (see Chapter 5, Fig. 14), was delivered two years later. He explained his simplifications, adjustments and improvements, and claimed ‘my Watch is reduced to much greater simplicity than Mr Harrison’s and may be much easier adjusted; therefore may be made at a less expence’.18 Kendall expressed confidence in its performance but also indicated that he had come up with an even simpler design. The Board agreed to let him try, and K3 was delivered for £100 in 1774 (see Chapter 5, Fig. 17).
By the 1770s, the Commissioners were thoroughly focused on Kendall’s simplifications and the work of another maker, John Arnold (1736–1799). Although Arnold first came before the Board in 1770, it appears that Maskelyne had already singled him out as a talented workman who might be put to good use, for he had sent him a copy of The Principles of Mr. Harrison’s Timekeeper. At the same meeting at which Kendall said he could make a watch for £200, Arnold had shown his own timekeeper, claiming that with further work it might be made for just sixty guineas (£63). The Board was impressed enough to advance him £500 to continue with his work.
Arnold was clearly influenced by the published description of H4 in Principles, and certain details were copied directly from its engravings. He had also taken up hints from elsewhere, including Maskelyne’s report that Harrison thought his timekeeper would be better placed in a wooden box than a silver case. Arnold’s early marine timekeepers therefore look more humble than H4 or K1, although they included precision work (Fig. 12). They also contained a new type of detached escapement, known as a detent escapement – an idea probably borrowed from France – which was effective in reducing interference between wheels and balance, which Harrison himself had said was desirable. From 1771, after tests at the Royal Observatory, Maskelyne instigated plans to have these watches tested on James Cook’s second Pacific voyage, alongside K1.
The desire of the Commissioners to publish and share information contrasted sharply with Harrison’s instinct to protect his methods. When the explanation of his watch had first been mooted in 1763, members of the Board had even invited the French to send nominated experts to join the witnesses. The mathematician Charles-Étienne Camus and the clockmaker Ferdinand Berthoud (1727–1807) were selected and arrived in London. Since this planned disclosure did not take place, they attempted to get information directly from Harrison, making contact through the French astronomer Jérôme Lalande, who was then resident in London.
Harrison refused, both in 1763 and again when Berthoud returned to London in 1766. Industrial espionage, including attempts to transfer the secrets of the London instrument trade overseas, was a feature of the period, and artisans jealously guarded their secrets and access to their workshops. However, Harrison’s clocks were not a typical case of intellectual property. Berthoud was, therefore, able to get a description of the watch directly from Thomas Mudge when they met at the house of Count Bruhl, who also acted as interpreter. Harrison complained but Mudge explained that he considered this openness to be desirable: ‘I thought it my duty to do it, and that it was the Intention of the Board I should do so’.19 He had also shared the information with ten to twelve English workmen.
Berthoud’s personal qualities stood in marked contrast to Harrison’s and were, it would seem, distinctly more amenable to and in accord with the mores of the Paris and London scientific academies. Berthoud, Camus and Lalande were all elected as fellows of the Royal Society in 1764, and it is notable that Berthoud’s election certificate, as well as mentioning that he had been chosen to witness the much negotiated ‘discovery’ of H4, stresses the fact that he had published several books describing his work on marine timekeepers, had willingly shown his clock to the Académie des Sciences and had deposited it with their Secretariat.
Fig. 16 – Marine timekeeper H5, by John Harrison, completed 1770
{The Trustees of the Clockmakers’ Museum}
Berthoud did not gain sufficient information to make watches like Harrison’s, despite his conversation with Mudge and possession of Principles. It is possible that the tight-knit clockmaking circles of London shared an understanding of Harrison’s work and skills that the clockmakers of Paris could not. Certainly Harrison’s descriptions were no help. The clockmaker Charles-Pierre d’Evreux de Fleurieu reported that ‘he had veiled his works so as to let them be seen without that it is possible to copy them’.20 It is likely, though, that Berthoud would not have followed Harrison’s path even if he could. The quality and accuracy of his marine timekeepers has sometimes been questioned but his focus, during a long and successful career, was on producing a good number of sufficient timekeepers rather than a small number of exquisite ones (Fig. 13).
Berthoud was one of two clockmakers working on marine timekeepers with support from the French king, government and Académie. The other, his senior, was Pierre Le Roy (1717–1785), who, over time, succeeded in producing timekeepers incorporating three elements that horologists consider essential to the later development of the chronometer: a detached escapement, temperature-compensated balance and isochronous balance spring (that is, one that transmitted its driving force at absolutely regular intervals) (Fig. 14). However, his clock designs managed to be both too large and insufficiently robust for practical use, contrasting with Berthoud’s focus on utility. While the success of Harrison’s watch had depended on a high-energy balance that produced long, fast oscillations, Le Roy’s clocks had a large balance, with short, slow oscillations, and even his petites rondes– small timekeepers within gimballed boxes, produced from about 1771 – had, like most watches, a low-energy balance that was too easily disturbed by motion.
Neither Le Roy’s nor Berthoud’s timepieces owed much to Harrison’s designs. Just as the French had shown the way with the publication of astronomical tables for navigation, they had a long record of research and investment in the timekeeper method. Le Roy and Berthoud had begun their research in the 1750s, were trialling timekeepers in the 1760s and received rewards in the 1770s, expending significant energies along the way on battling each other over who had invented what and who was the more deserving of patronage, titles and commissions. Le Roy seems to have been the more difficult character, although he is credited for the originality of his work. Berthoud managed his negotiations better and was always ready to share and publish his ideas. Equally, he borrowed from others, but his focus on strength, usability, simplicity of manufacture and ease of repair were arguably more important. He was able to produce seventy timekeepers, many of which were used on voyages of exploration.
Knowledge of British and French work in marine timekeepers circulated widely in European maritime spheres. Harrison’s Principles may, for example, have influenced a watch made by the Dordrecht instrument maker William Snellen in the 1770s (Fig. 15). This watch contains elements reminiscent of Harrison’s work, although its construction is very different. In many countries, however, attempts to manufacture marine timekeepers did not take off until the late eighteenth or nineteenth century and even then sometimes unsuccessfully. The British makers had made a head start and, for some time yet, those wishing to purchase instruments of the highest quality would largely look to London.
The end of the Harrison affair
Although he had spoken of working on timekeepers in the plural, John Harrison, now in his late seventies, succeeded in making only one more marine watch, known as H5 (Fig. 16). Taking a new initiative, the Harrisons made contact with Stephen Demainbray (1710–1782), astronomer at George III�
�s private observatory at Kew, and requested a trial there. Demainbray raised the issue with the King in January 1772, and William Harrison was invited to Windsor. Long after the event, John Harrison’s grandson, also called John Harrison, reported that George III had then exclaimed, ‘these people have been cruelly treated’ and, ‘By God, Harrison, I will see you righted!’21
The meeting led to a trial of H5 at the Kew Observatory from May to July 1772. As with the sea and Greenwich trials of H4, the watch was placed in a box with more than one lock, to prevent tampering. In this case it was Demainbray, William Harrison and the King who were to be present for the comparisons with the regulator clock at noon each day. After a false start, which has rather unconvincingly been attributed to placing it too close to some lodestones, the watch performed impressively. The recorded daily rate of variation over the whole ten weeks, which saw fairly constant temperatures, has been averaged out at less than a third of a second per day (Fig. 17).
With one last crack at the Board of Longitude, Harrison sent a communication that was discussed at their meeting of 28 November 1772. This covered much old ground but added the new results for H5, showing ‘(as he alledges) it went very considerably within the ... nearest Limits prescribed’ by the 1714 Act.22 He hoped thereby to receive the remainder of the large reward. The Board called in William Harrison and stated that they saw no reason to change the agreed approach, which required an official trial. At this same meeting they took up Kendall’s offer to construct his third watch and heard that John Arnold was keen to have two more of his timekeepers tested. K1 and three Arnold timekeepers were concurrently undergoing the most rigorous of tests on board Captain Cook’s ships Resolution and Adventure.
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