Hannah Salisbury undertook a research internship at the National Maritime Museum in 2011 and has sent us this post based on her work, which revealed the story behind an unusual-looking compass now in the NMM collections:

By the 1790s, after decades of development, finding longitude at sea by using timekeepers or the lunar distance method was finally beginning to seem a practical reality. Yet these methods still had their problems, and there was scope for alternative suggestions.

In 1793 a man named Ralph Walker (1749-1824) appeared before the Board of Longitude with a compass of his own invention, which he promised would solve all of their longitude-based problems (and others besides). It was a grand claim for his instrument and method.

This was Walker’s first foray into designing navigational instruments. The son of a Scottish farmer, Walker went to sea in 1768 aged 19, and quickly became master of the merchant vessels on which he was sailing, trading to the West Indies, the Baltic and America. In 1783 he settled as a planter in Jamaica with his Irish wife Jane; making use of slave labour, they most probably grew sugar or coffee. It was also in Jamaica that Walker built a prototype of his compass, mostly out of wood.

The Governor of Jamaica was so impressed with the compass that he procured Walker a passage to London on the Providence under Captain William Bligh, to enable Walker to present his invention to the Admiralty and the Board of Longitude. Leaving Jane and their seven children behind, Walker arrived in London in August 1793. It would be six or seven years before he saw them again.

To carry out Walker’s method for finding longitude, a mariner would use the sundial attachment on the compass to align the instrument to the true north-south plane. Comparing this reading with the direction in which the compass needle was pointing gave the magnetic variation. This could, in theory, be used to discover the longitude, by finding where supposed ‘magnetic meridians’ intersected with the observed latitude. Walker believed that his method was simpler than lunar distances, cheaper than chronometers, and deserving of a substantial reward from the Longitude Commisioners.

Initial reactions may well have given Walker cause for hope. The results of trials were generally favourable; Admiral Macbride was so impressed with the compass that he ordered one to be made for his own use. However, the compass did not win glowing reviews all round. Nevil Maskelyne was particularly damning in his judgement, writing that the compass was neither particularly innovative nor useful.

Reporting to the Board on 6 December 1794, Maskelyne criticised both the compass and the theory behind it. The compass relied on the sun to work; on a dull day, it would be useless, and even on too bright a day its functioning would be compromised. Problems were also likely to be caused by the presence of iron on board ships, and Maskelyne thought that Walker’s innovation of placing the compass needle on its side was likely to cause it to warp. Lastly, in the ‘present improved state of navigation’, Maskelyne did not consider that the idea of finding longitude through magnetic variation had anything to offer.

Nevertheless, the Board did meet with Walker several times between 1793 and 1796, and sent his compass for repeated trials. Unfortunately for Walker, his longitude solution was indeed doomed to failure. He had oversimplified the laws of terrestrial magnetism, and in any case the presence of iron on ships would always be a problem for taking compass readings.

Although the compass was not considered a viable longitude solution, it was seen as an improvement on other compasses then available, and this seems to be the light in which the Board saw it. Eventually, in June 1795, after repeated pleas for justice from Walker, the Board awarded him £200. The compasses proved popular with naval men, and were still in use in the 1850s. Nevertheless, only four are traceable today, one of which is held by the NMM.

Although Walker would remain interested in the fate of his compasses, his main life’s work was actually as an engineer. He began this new career in 1795, his first work being the West India Docks – a quite remarkable achievement given that the docks were the largest construction of their kind in the world, and that Walker apparently had no engineering experience whatsoever. Over the remaining 27 years of his life, Walker worked on several other dock schemes, as well as harbour improvements, canals and the East London Water Works, and launched the career of his nephew James Walker (1781-1862), who went on to become one of the best-known civil engineers of his day.

Walker was a clever and determined man, who took a great risk leaving his family in Jamaica while he took a chance on winning a longitude prize. Although he was not as successful in this as he had hoped, it led him to London and new work furthering Britain’s commercial and maritime interests through dock construction.

Today is the 277^th anniversary of the death of John Arbuthnot, Tory physician and Augustan satirist. He might not seem an obvious subject for a post on this blog, but he is, in fact, a perfect example of the ways in which the longitude problem linked in and out of all different areas of eighteenth-century society.

Arbuthnot was a well-respected mathematician and society physician in the reign of Queen Anne; a member of the Royal Society, an intimate of the Tory ministry of Robert Harley and Henry St. John Bolingbroke, and resident at Court until the ministry’s fall and the death of Anne in 1714; the year, of course, that the longitude act was passed. In 1701, he published the influential Essay on the Usefulness of Mathematical Learning, in which, among many other points, he argued for the importance of mathematics in astronomy and navigation. The former included the use of Jupiter’s satellites to find longitude, and the latter the recent important voyages by Edmund Halley on HMS Paramore to establish magnetic variation as a means of measuring longitude. Arbuthnot commented of Halley’s voyages that ‘those who sent him have, by this Mission secured to themselves more true Honour and lasting Fame, than by Actions, that at first View appear more Magnificent.’[1] This, his respected position in Court and government, and his Fellowship Royal Society, led to Arbuthnot’s appointment in 1705 to the committee set up to oversee the publication of the star charts made by the Astronomer Royal John Flamsteed, the Historia Coelestis, which eventually appeared in 1712. The arguments between Flamsteed and Newton over this publication are well known, as is the bitter outcome, in much of which Arbuthnot served as the go-between, placating Flamsteed and checking some of the charts and calculations himself.

Alongside these roles, Arbuthnot was also a popular and accomplished satirist. He met the Tory pamphleteer and novelist Jonathan Swift in 1710-11, commencing a deep and life-long friendship between the two. By 1713 they had formed the famous ‘Scriblerus Club’ with other satirists Alexander Pope and John Gay, along with essayist Thomas Parnell, and the Lord Treasurer Robert Harley, by now elevated to the peerage as Earl of Oxford. This group spawned the formative texts of the age including Swift’s Gulliver’s Travels, Pope’s Dunciad and their combined work The Memoirs of Martin Scriblerus. It is clear that Arbuthnot was the ‘science man’ of the group contributing the natural philosophical jokes and satires. The role of Martin Scriblerus was a perfect foil for these friends, allowing them both to write their own satires on contemporary literature and life, and to claim others’ works which they thought ridiculous as products of Martin’s pen. It was in this context that Arbuthnot first satirised longitude as an impossible scheme, soon after the 1714 Act. He wrote to Swift regarding Whiston and Ditton’s project for using bomb vessels, that ‘Whetstone has at last publish’d his project of the longitude, the most ridiculous thing that ever was thought on; but a pox on him, he has spoild one of my papers of Scriblerus, which was a proposal to this purpose, not very unlike his,’[2] and Swift clearly took great glee in replying that ‘It was a malicious Satyr of yours upon Whiston, that what you intended as a Ridicule, should be any way struck upon him for a Reality.’[3] Accordingly, Whiston and Ditton’s project went on to feature as one of Martin’s absurd projects in the Memoirs.[4]

It seems probable, however, that Arbuthnot also entered the longitude debate more directly. In 2008, Pat Rogers suggested that a pamphlet long thought genuinely to come from the pen of its named author Jeremy Thacker, The Longitudes examin’d, was in fact a satire on the over-inflated longitude projects then proliferating in pamphlet form thanks to the Act, and that it was written, in fact, by Arbuthnot.[5] The pamphlet proposed a scheme for keeping time accurately at sea by placing a clock in a vacuum. Jonathan Betts and Andrew King pointed out in reply to Rogers that the scheme did make some technically complicated and important improvements to contemporary ideas on clock making.[6] Yet, it is also heavily satirical in tone. Thacker opened by addressing his competitors in ‘A Short Epistle to the Longitudinarians’ in which he criticised their schemes and their writing style in exactly the manner which Swift had critiqued hack literature in A Tale of A Tub in 1704, and Pope would later in The Dunciad in 1728. Thacker commented how ‘without Animadversions upon the Attempts of others, I could not swell this to a Six-penny Book, unless I had embellish’d the Recommendation of my new Device with fine Metaphors, and clever Comparisons … I might indeed, with the Printer’s good Management, have made four Pages of the Commissioners Names in Capitals, and then have humbly submitted my Essay.’[7] The whole pamphlet is then made up of digressions and over-inflated statements, taking pages to get to the invention itself. It ends with the comment that ‘I am satisfy’d that my Reader begins to think that the Phonometers, Pyrometers, Selenometers, Heliometers, Barometers, and all the Meters are not worthy to be compar’d with my Chronometer.’[8] Interestingly, he makes one of the first uses of the word chronometer. I think that Arbuthnot probably created ‘Thacker’ in partnership with another author (as the Scriblerians did with other more specialist satires), possibly the clockmaker William Derham who was also an FRS, shared many views with Arbuthnot, and also started to use the term chronometer at this time. But, that is a subject for another blog post.

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[1] John Arbuthnot, An Essay on the Usefulness of Mathematical Learning, p.49
[2] The Correspondence of Dr John Arbuthnot (ed.) Angus Ross (Munich, 2006); Arbuthnot to Jonathan Swift, London (17 July 1714) pp.191-2
[3] Ibid., Jonathan Swift to Arbuthnot, Letcombe (25 Jul 1714) pp.195
[4] Memoirs of the Extraordinary Life, Works and Discoveries of Martinus Scriblerus (ed.) Charles Kirby-Miller (Oxford, 1988), p.167
[5] Pat Rogers, ‘Longitude forged: How an eighteenth-century hoax has taken in Dava Sobel and other historians,’ in Times Literary Supplement (12 November 2008)
[6] Jonathan Betts and Andrew King, ‘Jeremy Thacker: Longitude imposter? in Times Literary Supplement Letters (18 March 2009)
[7] Jeremy Thacker, The Longitudes Examin’d (London, 1714), p.11
[8] Ibid., p.23

Today is the 250th anniversary of the death of Tobias Mayer, the man who was posthumously rewarded for his important work on lunar theory by the Board of Longitude (or, more accurately, his wife was paid to hand over Mayer’s work). The long story of his dealings with the Board, particularly as a foreigner, will have to wait for another post, but given the attention we gave to Maskelyne on his anniversary last year, it seems right to mark Mayer today. Fortunately, over at Renaissance Mathematicius, Thony Christie has done our work for us. So please do go and read his post: How far the moon?

In response to my post on The Life and Opinions of Tristram Shandy, Gentleman, Patrick Wildgust, Curator of Shandy Hall, has alerted me to an interesting film by Thomas Newton.

Shot in and around Coxwold, where Sterne lived while writing Tristram Shandy, it takes its inspiration from a passage from the book to explore the perception of time. Patrick says that it was ‘an attempt to show layers of time using both Sterne’s experimental approach to the subject and the practical task of keeping it accurate in Coxwold’.

Incidentally, the latest exhibition at Shandy Hall, Precious Cargo, has a maritime theme.

See what you think, and thanks for sharing this, Patrick.

I have recently been working on a small display at the Royal Observatory (opening next month) called Measuring the Universe. Despite being small-scale the topic is – in every sense – vast. The Observatory’s Public Astronomer, Marek Kukula, and I are trying to cover the history of measurements of the scale of the solar system, the distance to the nearest stars, the space between galaxies and to the Cosmic Microwave Background. This takes us from the Earth to the edge of the known universe, and from Greeks to researchers today.

I have been focusing on the story of measuring the Astronomical Unit, that is the distance between the Earth and the Sun, and mainly on the use of the rare astronomical phenomenon of the transit of Venus to measure solar parallax. In 1761, 1769, 1874 and 1882 there were a huge number of observations made, across the world, motivated by the hope of establishing a scale for the workings of the Newtonian solar system, thereby improving astronomical theory and predictions, but also by a range of practical, geographical, national and imperial interests. A useful list of historic transit observations can be found here.

There are three good reasons for turning over half of the exhibition to this story: 1) there is a transit of Venus happening this June, probably the last opportunity to see it in any of our lifetimes 2) the Royal Observatory and its staff were much involved in the effort of organising expeditions, observing transits and reducing the data to produce results and 3) transit observations required overseas expeditions, as measuring solar parallax required observations from different latitudes, which involved maritime navigation, exploration and a host of themes of interest to the ROG, the NMM and me, as curator and a member of the Longitude project team.

Distilling down a story that includes Edmond Halley, Nevil Maskelyne, James Cook, George Airy and a host of the ROG’s assistants – to indicate just a few on the British side – has been challenging, to say the least! The main mission is to convey an idea of the method, the amount of organisation and effort required, the international nature of the enterprise, and the wide interest that it evoked, well beyond the scientific world. With the international story, I have tried to show that the co-operation that took place with regard to promoting expeditions and collating results was probably less significant than the national rivalries, the dangers of travelling during the war, and the selection of locations for observing that related directly to imperial and trading interests.

There are so many fascinating stories to which we cannot do justice in the available space. I am hoping to include one of the best – the sad tale of Guillaume Le Gentil – but it is impossible to explore the background fully. This includes the Seven Years’ War and, specifically, the French/British rivalry in the Indian Ocean and desire for access to India and trade routes. This military and geopolitical history does not always get enough attention in the story of longitude. Not only did overseas trade and competition provide a spur to finding a solution, the process of finding one was sometimes impeded by war (for example, when Harrison’s first timekeeper was to be tested, they were unable initially to make the journey to the West Indies required by the 1714 Act), and sometimes , of course, contributed to the extension of imperial interests – as in the voyages of Cook and those who followed.

Because the history of transit observations is wound up with that of Cook (his first voyage was a transit expedition, as well as a testing ground for the new Nautical Almanac and a mission to locate and claim the southern continent), the current interest surrounding the 2012 transit has encouraged some to think about longitude and navigation. I spotted, on The Transit of Venus site blog, a post by Nick Lomb on How Cook navigated to Tahiti. This includes a discussion of the extent to which Cook knew “his position at all times” as a result of having access to the first edition of the Nautical Almanac. This mainly focuses on the point that lunar distances won’t work in cloudy skies, but misses the fact that Cook and Charles Green (the official astronomer, and former ROG assistant) ran out of Nautical Almanac predictions over the course of the voyage and that the length of time it took to calculate position by lunar distance usually meant that the navigator would only know where he had been rather than where he currently was. Precise position for charting and, especially, for locating observers of the transit of Venus would have been carried out by observing transits of Jupiter’s satellites rather than, or as well as, lunar distances.

Readers of this blog might also be interested in the current voyage of the replica of Cook’s ship, HMB Endeavour, owned by the Australian National Maritime Museum. The crew is currently cirumnavigating Australia and will stop at Lord Howe Island (named after Richard Howe, a regular attendee of Board of Longitude meetings in the 1760s, as Treasurer of the Navy, and in the 1780s, as First Lord of the Admiralty) to observe the transit of Venus. Those on board, either for the whole circumnavigation or for the transit of Venus leg, will be learning and using 18th-century sailing and navigation techniques. I am assuming that they have 21st-century backup!

Alexi mentioned in a previous post that one of the interesting questions for our project is the survival, or not, of the sources with which we deal. Alongside that comes the question of the history of our main archive at the Cambridge University Library. Alexi mentioned that we know the volumes were arranged and bound as we now have them by George Airy, then Astronomer Royal, in the 1850s, and how he commented on their potential as a resource.

A recent new addition to our project is a digitisation side-project at the UL, funded by JISC. We will be making the entire 68 volumes of the Board of Longitude archives available online with summaries, commentaries and biographical information, in a similar format to the wonderful new Newton Papers resource. Those of us on the project who are charged with writing the summary for each volume therefore have the enjoyable task of going through each volume and making it clear how its contents fit into the history of the Board, and the stories told of it so far.

While writing my summary of Volume 1 last week, I came across this note, which was clearly accidentally bound in with the papers in the 1850s. It’s a letter from Airy to Edward Stone, who was Chief Assistant at the Royal Observatory in 1865. It’s interesting that Airy was asking Stone to go through the Board records in the 1860s, and trying to join up the correspondence with the minutes. Exactly what we are now trying to do!

As an academic research project we are, of course, interested in making an impact – through museum displays and public programmes, through this blog and other forms of media. It was, therefore, particularly heartening to catch, as it were, one moment of impact almost as it took place.

Thony Christie, author of the Renaissance Mathematicus blog and regular commenter here, flagged up a post on the Science Blogs blog Uncertain Principles, by Chad Orzel, an Assistant Professor in the Department of Physics and Astronomy at Union College in Schenectady, NY. He had put up a post asking how to pronounce ‘Maskelyne’, as he was about to teach a class on the history of timekeeping using Sobel’s Longitude as a text. Thony and I both commented there, highlighting the rather different story we have been touching on in this blog, but thanks for what happened next goes mainly to Thony as my comment got lost in moderation for some time!

A couple of days later, Chad had taken his class and reported back in another post:

This week was all about Dava Sobel’s Longitude, and the making of seaworthy chronometers. I said half-jokingly that the week followed a sort of a course through Union’s curriculum: Monday was on the science of navigation, using the experimental results presented here; Wednesday was about the engineering of clocks, specifically John Harrison’s innovations for his marine clocks; and today was the humanities side of things, presenting the story of Harrison’s attempts to get paid. Those last slides are really sketchy because I spent most of the class having them provide details of the Harrisons’ grievances against the Board of Longitude, as related by Sobel. I then provided a bit of the other side of the story, from the Board of Longitude blog: (Rehabilitating Nevil Maskelyne, Part One: Reassessing the accusations, Part Two: Why lunar distance?, Part Three: Cultural differences, Part Four: The Harrisons’ accusations, and conclusions) and this law review article (PDF) looking at the case in a more balanced way than Sobel’s book.

I’ve been saying repeatedly that this class is about learning how to make arguments, and so introduced the additional material by asking them if they could find holes in Sobel’s argument. They did a pretty good job of picking up on places where she glosses over inconvenient details, so I think it was a useful class.

Good news! And well done to Alexi for her setting-the-record straight series. As Chad commented on the earlier post, “The Board of Longitude blog is a very nice and compact counterpoint” to the suspiciously tidy story told by Sobel.

I find it striking how our understanding of the early Board of Longitude is defined as much by the absence of evidence as by its presence. For example, there is the perennial question: Was the gathering of 30 June 1737 truly the first official communal meeting of the Commissioners to have ever taken place? There are reasons to question whether or not this is true. Sources including the private papers of Nevil Maskelyne show that other formal (and informal) meetings of the Commissioners took place besides those entered into the ‘official’ minute books – although so far none are known to have occurred before 1737.

The existing records of the activities of the Board may have also been shaped and reshaped by the ways in which they were produced and compiled. For example, the minutes were often based upon the notes or later summaries of one meeting attendee – in many cases Maskelyne until his death in 1811. They were also later compiled and in some cases recopied at different times and for different reasons, in the process of which some errors were made. The selection and presentation of the extant Board minutes may have been further shaped by the later Astronomer Royal George Airy, who collected, reorganized and had them bound in 1858.

Eoin found a lovely quote from Airy regarding the end of this enterprise: ‘The Papers of the Board of Longitude are now finally stitched into books. They will probably form one of the most curious collections of the results of scientific enterprise, both normal and abnormal, which exists.’ You can see in the photo below a note written by Airy which is bound alongside the earliest surviving minutes in volume RGO 14/5 (now at Cambridge). How much did Airy’s rearranging and labeling of such documents (for example, as ‘impractical’ schemes) affect historians’ views of the Board? Could Airy or an earlier archivist also have disposed of some of the records which he deemed unimportant to the ‘official’ history of that body, for example from before the ascendance of John Harrison?

Some documents which are vital to understanding the history of the Act of 1714 and of the ‘Board’ have definitely fallen through the cracks. For example, there appears to be no extant copy of the famous petition to Parliament of 25 May 1714 from ‘several Captains of her Majesty’s Ships, Merchants of London, and Commanders of Merchant-men’ which is thought to have truly started the ball rolling towards the establishment of a longitude reward. Without knowing more details about its contents than have survived in the records of the House, there is so much which we can’t discern.

Was the petition truly an unprompted outpouring of concern from the nation’s maritime interests, or was it directly instigated or perhaps even scripted by William Whiston and Humphry Ditton? Whiston and Ditton had started lobbying for a longitude reward by 1713, and there are certainly similarities between the summarized contents of the petition and the contents of these two projectors’ publications. And could the contents of the petition have directly informed a draught Parliamentary bill now in the United States, which would have levied a duty on all shipping in order to provide British vessels with the means of finding the longitude?

If we go back further, even the original events of the early history of ‘the Board’ were marked by an absence of information. As I explain at greater length in an upcoming article, the Act of 1714 did not actually establish a standing body or ‘Board’ – but some percentage of contemporaries did not know this. We have not yet come across evidence that the detailed contents of the Act of 1714 were ever widely publicized, for example through the spread of handbills. Jane Squire, the only female longitude projector known to date, had to ask the Attorney General to read the text of the Act to her in 1731. As a result, it is not just longitude projectors but also the Commissioners themselves who expressed some confusion during the ensuing decades about their legislated nature and about the intended conduct of the longitude contest.

When eight Commissioners met together at the Admiralty on 30 June 1737, it seems to have received limited coverage, which did not necessarily mention the Act of 1714. For example, the London Evening Post simply reported that these ‘Persons of Distinction, view’d a curious Instrument for finding out the Longitude, made by Mr. Harrison’. When Squire wrote to Sir Charles Wager four years later to continue her decade-long campaign to have the Commissioners consider her proposal, she was not aware that the officials had ever met communally.

Photo credits: Cambridge University Library.