Longitude Season has started…

There has already been plenty of longitude on this blog, The H Word and the Longitude Project blog, so apologies that there is more to come. This has all been leading up to 2014, the tercentenary of the first Longitude Act, and the start of Longitude Season at Royal Museums Greenwich. It seems like a good idea to put in one place where we’ve been and some of what’s happening this year.

The Board of Longitude Project logo.
The Board of Longitude Project logo.

First came the Board of Longitude Project. A five year, AHRC-funded research collaboration between the National Maritime Museum and the Department of History and Philosophy of Science at the University of Cambridge. The team is/was: Principal Investigator Simon Schaffer, Co-Investigators Richard Dunn (Senior Curator and Head of Science and Technology at NMM) and me; two postdocs (Alexi Baker and Nicky Reeves) and three PhD students (Katy Barrett, Eoin Phillps and Sophie Waring). Very shortly joining us as engagement officer is Katherine McAlpine.

Then came the brilliant digitisation project, a JISC-funded digitisation of the Board of Longitude archive, together with related papers from Cambridge University Library and the NMM. Because of its association with the research project and the Museum, this came with lots of add-ons beyond the scanning and listing, and you can read more on the site and at my Guardian post here.

This year is about delivery and public engagement: four exhibitions, two books and a conference (although there’ll be more scholarly books, collections and articles to come out of the project in following years).


Already open at the Royal Observatory is Longitude Punk’d, which is a steampunk intervention (invasion?) into the courtyard and Flamsteed House that plays with existing spaces and displays, the themes of travel and longitude and with art/science, fact/fiction, real/fabricated. You can read more about it in this post by curator Heloise Finch-Boyer. It is inventive, playful and very funny, but can also confuse and is not necessarily to everyone’s taste. As a response to the problem of denuding the existing galleries in order to put on the main longitude exhibition (see below), it is really brilliant. Once the two exhibitions exist together I hope everyone will be happy! Hashtag is #LongitudePunk’d

Also at the Observatory is a small image and text display, Start to Satellites, about the development of satellite navigation, which takes the story of navigation well beyond the 18th and 19th one about longitude.

Next up will be the main event: Ships, Clocks & Stars: the Quest for Longitude, opening to the public on 11 July. It is an object-rich, historical telling of the story, supported by AV and interactives, with Richard Dunn as the lead curator, me (though my involvement has somewhat diminished since I left the museum) and an NMM team involving Kris Martin, Claire Warrior and Matt Lawrence. I hope it will be fab, and you will hear more anon! Hashtag is #ShipsClocksStars

Last to open will be Art and Science of Exploration, a rehang in The Queen’s House that focuses on the art surrounding the voyages of James Cook. It will be the first opportunity to have Stubbs’s kangaroo and dingo properly on show, alongside paintings by Hodges and Webber. In many ways it will be a natural extension of the main exhibition, which features a section on Cook’s voyages, a key testing ground for new longitude techniques. Hashtag is #ArtSciEx

There will be lots of events on during the run of the exhibitions, so keen an eye on the website. The hashtag for the season as a whole is #WhereOnEarth.


The official book accompanying the exhibition has been written by Richard Dunn and me, and is published by Collins. Called Finding Longitude, it is already available on Amazon for pre-order. It’s available on Kindle and a paperback edition will be sold in the exhibition shop (with luck the hardback trade edition will also make it to paperback?). This follows the same narrative as the exhibition, taking the story well beyond Sobel’s John Harrison focus, and is beautifully illustrated with historical painting and objects. It is out on 19 June.

Out in the autumn is a collection of essays on Nevil Maskelyne, published by Hale Books, called Maskelyne: Astronomer Royal. I have edited it and there are chapters and sections by me, plus chapters by Jim Bennett, Mary Croarken, Nicky Reeves, Rory McEvoy, Alexi Baker, Caitlin Homes and Amy Miller, largely coming out of the symposium we held back in 2011. This should also be well-illustrated with images from the NMM’s collections and, although not in any way replacing Derek’s Howse’s biography of Maskelyne, adds some interesting different angles.


The big conference for the project, and the exhibition, is Longitudes Examined: Tercentenary Conference on the History of the Board of Longitude and the Determination of Longitude at Sea. The programme is now available online and looks brilliant (I’m not speaking, although will be part of the final discussion panel, so I’m allowed to say that)! 

Barbados or bust: longitude on trial

Cross-posted from The H Word blog, where this post first appeared on 9 September 2013.


Barbados beach scene (perhaps not quite what Nevil Maskelyne experienced in 1763)

On 9 September 1763 a young curate and Fellow of Trinity College, Cambridge, set off for Portsmouth. He was to travel to Barbados on a voyage that would test the accuracy and practicality of three different methods of finding longitude at sea. At stake were potential rewards from the Board of Longitude.

The curate, Nevil Maskelyne, was also an astronomer and mathematician who became Astronomer Royal in 1765. I am currently editing a book of essays centred around Maskelyne, which, like the book I am co-authoring on the history of longitude, is due out next year for the tercentenary of the first Longitude Act. Working toward that anniversary, I spotted this one.

Back in 1763, Maskelyne was instructed to do two things. Firstly, he was to make longitude-determining astronomical observations during the voyage and, secondly, to make observations on land when the ship arrived in order to determine the island’s position, a prerequisite for an effective trial.

The three “methods” under trial in 1763 would be deemed successful if they succeeded in predicting Barbados’s longitude to within a degree or half a degree. They were:

1) A marine chair made by Christopher Irwin that was intended to steady an observer to allow him to measure the positions of Jupiter’s satellites at sea. (Eclipses of Jupiter’s moons were already used as a celestial timekeeper* to determine longitude on land: these were the observations Maskelyne made at Barbados.)

2) The latest version of the lunar tables of Tobias Mayer, which helped predict the position of the Moon and allow it to be used as a timekeeper using the lunar-distance method.

3) The latest mechanical marine timekeeper, and first sea watch, made by John Harrison.

Maskelyne and his assistant, Charles Green, were to make the ship-board observations and calculations necessary for the use of the first two methods. Harrison’s watch, now known as H4, would travel out separately with Harrison’s son William.

All of the methods worked in theory; the sea trial was to establish whether they worked reliably in practice. Only Irwin’s chair was a failure. Remarkably, two plausible methods of finding longitude had, finally, come to fruition at almost exactly the same time:

1757: Mayer sent his theory of the Moon’s motion to the Board of Longitude. It proved capable of making pretty good predictions – an object that had defeated Isaac Newton’s best efforts. Harrison, who had received rewards amounting to £2750 during 1737-1757, abandoned the development of his large marine clocks (H1H2H3) and thew his efforts into his watch.

1761: The potential of Mayer’s tables and the lunar-distance method was demonstrated by Maskelyne and his assistant, Robert Waddington, during a voyage to St Helena, where they had been sent by the Royal Society to observe the transit of Venus. Harrison sent his watch on trial to Jamaica and claimed an excellent result. Unfortunately, the trial was declared void because of uncertainties about the longitude of Jamaica and the watch’s rate, Harrison had to make do with another £1500.

1763: The Barbados trial was the really significant one – Mayer’s tables (via the lunar-distance method) and Harrison’s watch were both officially found to have met the necessary criteria. The Board of Longitude had two methods on their hands… potentially.

The lunar-distance method was complex and time-consuming and could only become useful if enough navigators were trained to undertake the required observations and calculations. Ideally, part of the work needed to be done for them, via the publication of regularly updated predictive and pre-calculated tables.

Harrison’s watch had worked well, but the question was whether another such machine could ever be made. Could one be made by another workshop? Could a marine timekeeper be made that was less costly than the exquisite H4?

In 1765, an Act was passed that divvied up the spoils and aimed to help make these potential methods “practicable and useful”. Harrison would receive £10,000 only if he revealed his method (i.e. the mechanism and the methods and materials involved in the construction of his watch) to other artisans. A further £10,000 would be paid out if more timekeepers could be made and successfully tried.

Tobias Mayer had died in 1762, but £3000 was paid to his widow in return for his papers. £300 went to the mathematician Leonhard Euler as a reward for his equations, which had greatly enhanced the accuracy of Mayer’s tables. A further £5000 was held out as a reward for the future improvement of the tables and, perhaps most significantly, the Board committed to the regular publishing of a Nautical Almanac, to be overseen by the brand new Astronomer Royal, Nevil Maskelyne.

The Barbados trial was not a competition or a race for a prize, although Christopher Irwin certainly found his marine chair out of the running. Rather, it confirmed two promising methods that required further investment. The Board of Longitude committed to this, seeing that they were not mutually exclusive. The lunar-distance method could be made available more quickly and was the only means of checking the performance of a ship-board timekeeper.

While Harrison’s paranoid belief that Maskelyne was prejudiced against him and his watch has become the dominant version of this story, it is not backed by the evidence. As Astronomer Royal and Commissioner of Longitude from 1765-1811, Maskelyne was to aid the development of both of the methods that his 1763 voyage had helped to prove.

* The difference in longitude of two places is equal to the difference in their local times.

Navigating 18th-century science: Board of Longitude archive digitised

Cross-posted from The H Word blog.

Today [18 July 2013] the complete archive of the Board of Longitude is being launched online, with stories of innovation, exploration and endeavour – and much more than just John Harrison

Design for a marine chair

Design for a marine chair submitted to the Board of Longitude. Source: Cambridge University Library


Today Lord Rees will be launching the digitised archive of the Board of Longitude at Cambridge University Library. Stuffed full of the correspondence and work of those who preceded him as Astronomer Royal, it also contains letters and papers of artisans, inventors, expeditionary astronomers and maritime explorers.

For those not familiar with the story of the 18th-century search for a means to determine longitude at sea, this video, gives an introduction to the project and the story.

The digitisation project is a collaboration between CUL and the National Maritime Museum, funded by JISC, and is closely allied to an AHRC-funded project on the history of the Board of Longitude that brings together researchers from the NMM and History and Philosophy of Science department in Cambridge.

This association has meant that as well as digitising 48,596 pages from the archives and libraries at Cambridge and NMM, the content is supported by links to relevant object records at the Museum, summaries of all and transcriptions of some of the files and essays on key figures, places, institutions, objects and events.

Written by the project researchers, there is enough text there for a couple of PhDs (at least) and a really useful resource for users of the site. I was the laggard who has only contributed one essay so far, on Astronomer Royal Nevil Maskelyne. He was, though, an extremely significant figure both for the longitude story and in this project, which also includes selections from Maskelyne’s archive from the Royal Observatory and his personal papers held now at the NMM.

While historical researchers will undoubtedly find many ways to start digging into the archive, for those newer to the game there are, on top of the summaries and essays, resources for schools and some selected stories lifted from the archive. The content can take the reader to the observatory at Greenwich, meetings at the Admiralty, artisan workshops of London and the South Seas.

William Wales' map of Easter Island, from Cook's Second Voyage

William Wales’ map of Easter Island, from Cook’s Second Voyage. Source: Cambridge University Library

Key Stage 2 pupils will, we hope, learn about Captain Cook’s voyagesand Key Stage 3 will be able to think about inventors and enterprise.

For those who feel they are familiar with the story of longitude, having read about John Harrison and his sea clocks in Dava Sobel’s Longitude, they will find there is much more to explore. As my NMM colleague, Richard Dunn says,

The archive places the familiar story of Harrison in its richer context. He was a crucial figure but the story is much broader. It takes in the development of astronomy, exploration and technological innovation and creativity during the period of the Industrial Revolution, the work of the first government body devoted to scientific matters, and public reactions to a challenge many considered hopeless.

Simon Schaffer, who leads the research project, adds that

The longitude story is a spectacular example of expert disagreement and public participation. As well as attracting the greatest scientific minds of the day, the board enticed people who belong to one of the most important traditions in British society; the extreme eccentric.

Thus while there may be interest in reading the full story of the Board’s dealings with Harrison, eyes are likely to be caught by what were damned by the archive’s 19th-century compilers as “Impractical schemes”. Some of these are real green ink stuff, with perpetual motion and squaring the circle bound into the seemingly intractable problem of finding longitude.

Scheme for dead reckoning

Proposal for finding longitude by determining the ship’s rate of sailing. Source: Cambridge University Library

However, there are many other schemes that, while they did not come to fruition, were based on sound ideas. These included improvements todead reckoning – the educated estimate of position that was not displaced by chronometers until the 20th century – or ways to steady an observer sufficiently to allow them to use Jupiter’s satellites as a celestial timekeeper (the standard means of determining longitude on land).

In its later life, the Board supported the two successful methods of finding longitude at sea – chronometer and lunar distance – and broadened its remit into other fields. Thus those who explore the digital archive will also land on geomagnetic researchpendulum experiments measuring gravity, the search for the North-West Passage and a young Michael Faraday pulled in to investigate ways to improve optical glass.

And much more besides – go on, dive in!

Did the Longitude Act speed up the solution to the longitude problem?

Cross-posted from The Longitude Project Blog.


I recently did a brief talk for some of the staff at Nesta, including their Centre for Challenge Prizes, on our project and  outcomes of our research. During the discussion, someone asked what is, particularly for them, a very pertinent question: “Did the Longitude Act speed up the arrival of a solution?”.

My answer was something along the lines of “sort of, possibly, probably no…”. It is not the kind of question that we historians are necessarily very good at answering, involving as it does the counter-factual world in which no such Act was ever passed by the British parliament. Still, it’s an interesting idea to play around with.

All the things that first came to my mind were the reasons why it didn’t make the blindest bit of difference. For a start, it was not the only potential reward available for whoever should come up with a viable longitude solution. As well as the earlier Spanish reward system, the Dutch version was still on-going, as were prizes on offer from the French Académie des Sciences. Had there not been the 1714 Act in Britain there might have been another one or initiatives organised through private individuals or institutions like the Royal Society.

Even without these schemes, plausible navigation-related ideas were always a potential means of gaining patronage and, if successful, could lead to honours, rewards, customers and a viable business. While the Longitude Act held out the possibility of a very large reward, it was certainly not the only or – for most people – the most likely way to make new ideas around longitude pay.

The question of “speed” is an interesting one. It is impossible to predict how long new ideas should take to develop, but when we consider that it is two decades before the Commissioners of Longitude met as a group, and another three before serious money was dispensed, it doesn’t sound particularly speedy. The 1714 Act had looked for a “practicable and useful” solution for the public, but there wasn’t anything widely available until a century later.

Something else that disrupts the idea of a prize having a quick and direct impact is the very international and collaborative nature of the potential solutions. The astronomical knowledge and mathematical tools required to make the lunar distance method workable were the product of many minds, in several countries. It was a process that might have been sped up by much larger sums of money being thrown at observatories to employ many more astronomers, but probably not by the possibility of a future prize.

The timekeeping method was also more international and collaborative than is often remembered. While a single clock can seem obviously the work of an individual, it incorporates the skills of many piece-workers and collaborators, knowledge of predecessors and availability of particular materials. These things are specific to time and place, meaning that new technologies only become possible in those circumstances. If the time was ripe for Harrison, so too was it for Ferdinand Berthoud and Pierre Le Roy in Paris and (possibly, or in time) for Thomas MudgeLarcum Kendall and John Arnold in London.

However, it is certainly true that the Longitude Act gained lots of attention and provoked lots of interest. It would also seem that the key players in the story – like John HarrisonJohn Hadley and Tobias Mayer – were, it not directly inspired to look at the problem as a result of the Act, certainly quickly interested in making contact with the Commissioners. Over time, their work was also to become of greater public interest and, therefore, better known as a result of the fame of the Act and all those involved in it.

It is probably also fair to say that Harrison would not have had the time or money to dedicate so much of his life to the problem without the financial assistance of the Board. I would also argue that investment in the later 18th century in the two methods – through the Nautical Almanac and other publications, trials, further rewards, training and so on – probably did speed up or at least allow their wider adoption. This, however, was only through new Acts and a changing understanding of the Board’s purpose.

All in all, my view is that had the 1714 Act, Harrison, Hadley and Mayer not existed, others would very probably have (and sometimes did) come up with similar solutions to the problems they tackled within somewhere around the same time frame. However, this is not necessarily a conclusion that I would claim for the progress of all reward schemes and challenge prizes. Things would be different should a prize, for example, highlight an issue people were unlikely otherwise to be working on or in a period with a much larger and more professionalised workforce than in the 18th century.

But that is only my view and, like all counter-factuals, probably begs to be shot down. I’d love to know what others think.

Report on Oceanic Enterprise conference

On 25-26 January, several members of the Longitude Project team were in California for our conference at the Huntington Library, Oceanic Enterprise: Location, Longitude, and Maritime Cultures 1770-1830. It was an extremely enjoyable and interesting meeting, which I attempted to summarise in a post over on the Longitude Project blog. (It’s worth clicking on the link to see Simon Werrett’s appropriately themed fantasy conference dinner menu, if not my ramblings.)

More than transitory interest: an instrument of note

Slightly belatedly, here’s a cross-posting of my last post on the Longitude Project blog, which takes a closer look at a significant astronomical relic:

A lesson quickly learned in the world of museum collections and displays – perhaps especially in history of science and technology collections – is that the appeal and aesthetics of an object only rarely match the interest of their story. It has been rightly stated that in many cases when an instrument has made its way into a museum collection, it is probably because it not much used for its ostensible function: it has been admired and collected rather than used, broken and thrown away. [Read more]

Long-distance longitude

Over a year ago I wrote a post ‘Sympathetic vibrations‘ that mentioned a 1688 pamphlet that included (as satire) a means of finding longitude by using a ‘Powder of Sympathy’. The idea was that this could be used to enduce an on-board dog to yelp at a pre-determined time at a known reference point, thus […]

There was no such thing as the Longitude Prize

As a result of the old question “Did Harrison win the Longitude Prize?”, and recent discussions on Twitter, started by Marcus du Sautoy here (he had been filming with the Royal Observatory’s Senior Specialist in Horology, Jonathan Betts, that day) and Tim Hartford (e.g. here), I have attempted to explain the various rewards offered and paid out by the Commissions of Longitude over on the Longitude Project Blog.

[Incidentally, Marcus du Sautoy’s tweet linked above reads:

As well as raising the issue of winning the ‘Longitude Prize’, this also suggests that the sea watch H4 was an improvement on the first of Harrison’s sea clocks, H1, because it was compact and could fit in your pocket. I’m sure, though, that du Sautoy knows very well – and that the TV programme will reflect – the fact that H4 was a radically different approach to the problem rather than just a smaller version of the previous attempts. In addition, it would have performed very poorly if it had been kept in a pocket. In fact, Harrison complained bitterly when Maskelyne tested the going of H4 while it was held at steeper angles then he considered feasible for an object left on a table on board a rolling ship. Later, of course, pocket chronometers were developed.]

Scheming Jack

Some time back, Adrian Teal was good enough to share a great quote with me, and it is high time that I got it up onto this blog. It is nice because it gives us a very different view of John Harrison, the humble carpenter from the provinces who dared to stand up to the scientific elite of the Royal Society and Board of Longitude.

The quote is from a biography of the aritist Thomas Gainsborough by his friend, Captain Philip Thicknesse, and reports the comments of Gainsborough’s brother John, known as ‘Scheming Jack’ because of his wild and somewhat outrageous inventions. [Read more]