Longitude in Lisbon

Cross-posted from the Longitude Project Blog.

I have just returned from a visit to Lisbon, where I had been invited to speak about the Longitude Act and project at the Seminário Nacional de Historia da Matemática. An added bonus of the visit was that an exhibition marking the tercentenary of the first Longitude Act had just opened at the Museu da Marinha.

It was a small display on the first floor that succeeding in getting across many of the key points about the Act, the various contenders for rewards and the Portuguese context. There were three cases of books, tables and charts, two of navigational instruments and a series of wall text and graphic panels.

The first panel was welcome reading, pointing out a long history, several valid areas of research and the development of two of these – the chronometer and lunar distances – as workable solutions in the second half of the 18th century. Although John Harrison was mentioned in the panel dealing with the development of timekeepers, the exhibition did not present either him or chronometers as the most significant part of the story.


Other panels were devoted to the navigational methods used before the Act, magnetic variation, Jupiter’s satellites, lunar distances, chronometers and the Portuguese context. The last of these included the role of Jupiter’s satellites in settling longitudes on land, especially those that had been contested by Spain and Portugal.

IMG_0147Objects included an altaziumth compass (to measure magnetic variation), a telescope (linking to Jupiter’s satellites, but not a type that could have been used for this tricky observation) a box chronometer and several instruments for astronomical observation.

Included among the printed material were books on navigation, ephemerides and almanacs. Among them were an 18th-century edition of the Nautical Almanac, a French account of testing timekeepers at sea, and several Portuguese ephemerides, including those based on the observations of the observatory at Coimbra University.

Two early charts on display also made use of a Portuguese prime meridian, and theIMG_0152 19th-century almanacs clearly played on a sense of history – a reminder of Portugal’s stellar role in maritime navigation in the past – and a claim to a central position in the globe, marking the division of the two hemispheres and the old and new worlds.

I got a good sense of the importance of Portugal’s maritime past to the nation during my visit to Lisbon. The conference was held at the Escola Naval where naval history and, by extension, the histories of navigation, mathematics and astronomy, were very evident. While Greenwich and other maritime location in Britain tend to celebrate the 18th-century Navy above all, many sites in Lisbon have (mostly 20th-century) paintings, mosaics and statues to the heroic navigators of the 15th and 16th centuries.

I was fascinated to learn about the myth-making surrounding the Sagres “School of Navigation“, supposedly founded by Henry the Navigator, and also the extent to which the regime of the 20th-century dictatorship had consciously developed and celebrated this heroic maritime and imperial history – to the benefit of institutions like the Naval School, observatory, museum and planetarium.


Being a guest at the naval base, and visiting the naval museum (still directed by a uniformed naval officer, who was kind enough to guide me around), was a truly memorable experience. I particularly enjoyed being entertained over lunch in the officers’ dining room with stories of the school, and having to teach and learn lunar navigation techniques.

The saying in the Portuguese Navy is that “the moon lies”, emphasising all the many things that can go wrong with instruments, observations and calculations, especially when officers are less and less used to performing them. However, the tables and sextants are still there as back up, not least because of concern about the ease with which GPS signals can be blocked or (more dangerously) tampered with.

Best of all, I was told a story of a ship’s commander, making for a large island but hampered by very poor weather and the loss of one navigation system after another. Left with just radar and dead reckoning, for a moment the moon appeared and he took his chance to take observations. Making his calculations, he couldn’t believe the result: “the moon lies”, he said to himself. But, continuing on his course, the island still didn’t appear and, eventually, he decided to go back to the lunar observation and try his luck – radar soon picked up the target destination.

It sounded like the tale of an old salty sea dog but, later that day, I met the man himself. He was in youthful middle age. The moon sometimes lies but, it turns out, sometimes, even now, she can still be pretty helpful.


On this day: the role of anniversaries

Newspapers, magazines, blogs and Twitter are awash with anniversaries. Today’s Birthdays, On this Day in History, #OTD and so on greet me every morning. I know a handful of famous people or events that share my birthday, and I am usually aware of forthcoming anniversaries for the people or institutions that I study. It cannot have escaped your attention that this year sees a Dickens anniversary and a royal jubilee. But why should it be in any way meaningful?

There is, of course, a meaningful history attached to the celebration of anniversaries, and one that has been studied by a number of historians. Looking at which, why and how famous individuals have been remembered for centenaries, bicentenaries and tercentenaries can tell us a great deal about how people view their own time, and how they make sense of their heritage, their nation, their discipline or their institutions. It is a product of that age of invented traditions, the 19th century. One of the scene-setters was the Shakespearian tercentenary in 1864, for which an ambitious programme of events was organised. By the early 20th-century such celebrations abounded: Shakespeare again in 1916, James Watt in 1919, Newton in 1927, Faraday in 1931, and many, many more. Many of the themes are touched on in this fascinating article on the Watt and Faraday celebrations, by Christine Macleod and Jennifer Tann (£).

Because of my sense of the fact that such celebrations tend to say more about us than they help develop a real understanding of the past, I’ve been pretty sceptical about anniversaries. This tendency was probably not helped by the fact that for three or four years it was my job to create a list of forthcoming anniversaries for the newsletter of the British Society for the History of Science (back issues here: there’s plenty more interesting stuff in there than these lists!). I was told by my elders and betters that it was a tradition and much appreciated by our members. In an era before Wikipedia, it probably was, but in my innocence I did not understand why.

Since entering the ‘real world’ of grant applications, large organisations and media relations, my eyes have been opened. While I still can’t quite understand why dates separated by a year, a decade, a century or whatever should be so readily accepted as having significance, I now understand why historians go along with it readily enough.

An anniversary seems to be the only way that history can be accepted as news, barring a really dramatic archival or archaeological discovery. Journalists, editors and readers are, it seems, more prepared to accept a story on an event/book/exhibition if it is connected to an anniversary – and, therefore, somehow carrying its own logic and relevance. Thus, publishers, directors and funders are more likely to be convinced that your idea is worth a punt. It also, of course, carries a natural deadline that helps to focus efforts, gain momentum and generate collective endeavour. A general sense that something must be done to celebrate this or draw attention to that can coalesce much more easily around a forthcoming anniversary.

It would seem that I have now become the anniversary’s greatest fan. Today I was delighted to see the marking of the 250th anniversary of Tobias Mayer’s death with a great post over at The Renaissance Mathematicus. I pointed readers of the Longitude Project blog toward it, especially since the bicentenary Nevil Maskelyne’s death last year was an excuse for a number of posts creating a more rounded portrait of the erstwhile ‘longitude villain’. The anniversary made it sensible to have a symposium devoted to the man, and also got him into New Scientist.

Of course, the whole Longitude Project, and the NMM’s forthcoming exhibition on longitude are also knowingly linked to the 2014 tercentenary of the first Longitude Act. I am now beginning to think that it would be worthwhile to start planning for the 350th anniversary of the Royal Observatory (OK, it’s not until 2025, but in the scheme of things, in a busy life, that’s not really so far off, if we’re to pull of a significant redisplay as well as suitable events). These institutional beginnings do, at least, carry a little more weight than birth and death anniversaries, that mark the two events in a life that the hero has least control over, but why should “founded 300 years ago” mean any more than “founded 298 years ago”?

Are we letting the cart lead the horse, in research terms? Should we be working harder to sell what we really think is significant instead of going for the easy option? Are anniversaries a harmless means of raising awareness, or can they obscure the importance of history: accounts, stories and interpretations which are for everyday, or perhaps for some unplanned particular day, and not just once every century. Did the huge Darwin bicentenary of 2010 achieve much, beyond sating everyone’s thirst for talks and TV programmes about the man? Have we, in short, made ourselves slaves to the anniversary?

An auspicious day to found an Observatory

The Royal Observatory has several possible birthdays. I have, for example, seen it given as 4 March or 22 June 1675. The first is the date of Charles II’s Royal Warrant that ordered the Board of Ordnance to pay for “the support and Maintenance” of John Flamsteed, appointed “our astronomical observator” and charged

to apply himself with the most exact care and diligence to the rectifying the tables of the motions of the heavens, and the places of the fixed stars, so as to find our the so much-desired longitude of places for the perfecting the art of navigation.

The second date is that on another Royal Warrant, this time authorising the construction of the “small observatory within our park at Greenwich, upon the highest ground, at or near the place where the castle stood”.Read More »