Jo Ritale: Yuma. And good evening everyone. My name is Jo Ritale, Assistant Director General of Collections here at the National Library, and it is my pleasure to welcome you tonight to this event. Before we begin, I would like to ask you to please ensure your mobile phones are turned off or are on silent. Thank you. To start, I would like to acknowledge and pay my respects to the traditional owners and custodians of this land and through them to all Australian Aboriginal and Torres Strait Islander peoples. The Library sits on the beautiful lands of the Ngunnawal and Ngambri peoples who know the terrain of this region intimately and we're the original mapmakers and place finders. I thank them for the care they have taken to look after this place for millennia and how they continue to do so for our programme This evening, we are pleased to host cartgraphic historian Chet Van Duzer as he discusses early modern maps and the methods used by Mapmakers to indicate certainty and uncertainty about the accuracy of their maps.

Today with Google Maps in the palm of our hand, able to pinpoint our exact location, zoom in and out, and get instant directions, it is easy to forget the complexity of making a map, especially when as Chet will discuss, you didn't actually know what was there with no way to find out unless you went on a grand adventure. Despite the lack of modern technology, you will see that early photographers produced incredible maps that were detailed, useful, and beautiful. The Library has an extensive collection of over 1 million maps from the late 15th century to today. I encourage you all to make use of this incredible resource for educational reasons or just for the sheer enjoyment of looking at these incredible objects. Chet is a historian of cartography and a board member of the Lazarus project at the University of Rochester, which brings multi-spectral imaging, a technology for recovering information from damaged manuscripts and maps to cultural institutions around the world. He has published several books on maps, my favourite being Sea monsters on Mediaeval and Renaissance maps with his current project focusing on self portraits by cartographers that appear on maps, the original selfie perhaps, and the historical cartography of the Indian Ocean. Clearly he knows his field. So without further ado, please join me in welcoming Chet to the stage.

Chet Van Duzer: Well thank you very much Jo for that generous introduction. It is a pleasure to be here this evening. I thank the National Library for the invitation and I hope my subject is an engaging one, the question of how exactly early modern cartographers dealt with the unknown. As we'll see, they had a variety of strategies for doing so. I'll begin by mentioning that the inherent plausibility of maps tends to make us ignore issues involving cartographers uncertainty, and I'll give us a few quotes about this inherent plausibility of maps. So Henry Wagner wrote, there is nothing that has such an error of verisimilitude as a map. And J Paul Goode in his world atlas wrote a well drawn map, creates an aura of truth and exactness. And Matthew Edney has said that every member of a modern developed society has been taught what to expect of a map. The map is accurate, is truthful, does not contain errors. So we tend to accept what we see in a map and as we'll see some cartographers are very content not to address. Questions of uncertainty are content to rely upon this inherent possibility of maps, this inherent aura of verisimilitude. Other cartographers do address the issue head on and we'll look at cases of both.

So here we have a manuscript world map made in about 1530, which has this very large dramatic southern continent and it's depicted with total confidence and if we zoom in we can see that it has the same imagery for topography and the same density of place names as the other continents. So it's presented as having the same reality value as everything else in the map. So here there's no indication of any uncertainty at all to accept that the level of detail in this southern continent indicates that we should accept it with the same faith as the other parts of the map.

So as I said, many cartographers are content to take of this prima facia aura of truth, but others acknowledge the weakness of some of their sources and the question arises as to which maps convey more authority. Those that do not mention problems with their sources or those that address those issues head on, those that acknowledge the problems and try to move beyond them. So recognition of the problems involved with the unknown and uncertainty in maps go back to classical antiquity. So Plutarch in his parallel lives writes j"Just as in maps, dear Sossius Senecio, the historians when they reach the limits of their knowledge compressed the unknown regions into the outermost parts of the charts and add explanatory notes such as 'beyond here are waterless deserts full of wild beasts' or 'a dark and muddy swamp', or 'Scythian cold' or 'a frozen sea'. So too, in composing the parallel lives, when I have passed through the time that can be reasonably grasped and supported by historical evidence, it is fitting to say about what lies beyond beyond here lie marvels and tragedies, the domain of poets and mythmakers where nothing trustworthy or clear remains." So very, very few maps survive from classical antiquity. And this description tells us a great deal about these maps that don't survive the fact that the cartographers were confronting problems of uncertainty. And they had these stock phrases for dealing with the unknown.

One simple option for dealing with the unknown and the uncertain is to omit it. So here we have a world map from Claudius Ptolemy geography, which was made according to his first projection. So he developed three projections for making a world map. This is his first projection. And just to orient ourselves a little bit, here's Europe, Africa, Asia, and the Indian Ocean. So this is the world according to his first production and he's not showing us the whole surface of the world, but with this projection we don't think about that so much I think. But he also developed his third projection, which we see here, and this is from the same manuscript in the National Library of France. So here he has placed the known part of the world on a sphere. So we have Europe, Asian, Africa, the three known parts of the world, and he's put it on a sphere with blank space indicating the unknown regions. So here he's very candidly admitting what he doesn't know and graphically depicting what he doesn't know. So this is a very forthright method for dealing with uncertainty.

Another way, another method for dealing with uncertainty is through visual signs. So the French cartographer, Pierre Descelier in his world map of 1550 developed a distinctive style for indicating unknown coasts that is he distinguished visually between coasts that he was confident about and coasts that he was not confident about. So here is his world map of 1550. It's one of the most spectacular world maps to survive from the Renaissance. And here I've indicated in green the coasts that were known, and here I indicate in red the coasts that were not known that are speculative. And these coasts, there's a logic to them. So the hypothetical southern continent, the coast is indicated as unknown. Northern Asia and northern North America are also indicated as unknown and also the coast of western South America, which we'll look at first. So if we zoom in, we can see this distinct style for indicating coasts that are known versus coasts that are unknown.

If the coast is known, it's dense with place names. If it's unknown, it's something very different. We'll zoom in on it here. So the unknown coast is a series of unnamed promontory separated by unnamed rivers, indicated by the letter R . For Descelier, what this means is this is an unknown coast. I'm not confident about this. He doesn't explain that on his map, but it's really the only possible interpretation. So he's being very forthright in declaring that he's less confident about these coasts and he uses this same distinctive style for other unknown coasts on the map. So if we look at the northern coast of North America, we see again these sort of uniform pro separated by unnamed promontory separated by unnamed rivers, and he uses the same style for his hypothetical southern continent. Again, these scalloped promontory with separated by rivers. So again, this is a very forthright way to deal with unknown coastlines. He indicates a coast, but he also indicates that he's not confident about it.

There are other ways that cartographers have dealt with uncertainty and one of those ways was to cover unknown territory with a cartoucheoon, so to hide conceal territory about which the cartographer was uncertain. And we can see that method used in Johannes Ruysch's world map of 1507, which we see here. It has an extensive programme of cartoucheus with descriptive texts and we'll focus on these two which are on the western coast of the new world. And Ruysch has placed these two cartoucheus precisely over the unknown coasts of North America. So rather than developing as Pierre Descelier did a distinctive style for indicating a less than complete confidence about a coastline, he just covers the coast with a cartouche on so he doesn't have to even attempt to draw a coastline.

We can see something similar on Gerard Mercator's world map of 1569. If we've heard the name of one cartographer, it's probably Gerard Mercator, he's famous for the Mercator projection. Just to orient ourselves a little bit as the contrast is not great on this image, here's Africa, south America and North America and we can see that here's the coast. We can see that a huge multi-part cartouche occupies much of the interior of North America. So that's one way in which he's using this cartouche conceal ignorance. He doesn't have to depict anything in the interior because he is covering it with this cartouche, but this cartouche has that same function in another way. So at the top of this cartouche, we have personifications of peace, justice and peity. One of the most important geographical and cartographic questions of the late 15th and particularly the 16th century was whether there was a northwest passage, whether it was possible to sail from the Atlantic around North America to the north to reach the Pacific and thus Asia and Mercator shows open water to the west and open water to the east. But right where we would hope for that answer to the question, do these bodies of water join? We have this large cartouche. So he's using the cartouche to avoid having to give an answer to that question.

Another case where a cartographer uses a cartouches to conceal ignorance and then within that cartouche maps uncertainty. So it's sort of uncertainty within uncertainty. This is Abraham Ortelius's Geograph of sacra. So holy geography first printed in 1598. This copies from 1612. So here we have the Nile and where we might hope to see the source of the Nile, we instead have this large cartouche. So he's using this cartouche to hide that uncertainty about the source of the Nile. And within that cartouche there's a map. And if we zoom in at the top of the map, he says he reproduces a sign, which is a sort of bullseye, a circle with a dot in it he says, this sign indicates the location of Ophir from the Bible and within the map he gives four possible locations for Ophir. So within his cartouche that hides uncertainty about the source of the Nile. He indicates uncertainty about the location of Ophir.

So some cartographers are very candid about distinguishing between certainty and uncertainty. And one of those cartographers is John Smith in his famous map of Virginia first printed in 1612. This copy is from 1624. In the upper right hand corner of the map he writes, signification of these marks to the crosses has been discovered what beyond is by relation meaning by account. And then he shows us this cross. So he's saying that what is as far as these crosses has been actually discovered? What is beyond the crosses is just by account, by report. And here I've indicated the location of these crosses on the map. So he's showing us very precisely to what extent his confident knowledge extends. And then beyond that he's heard something but is uncertain. So this is a very candid indication and a very precise indication of the boundary, the limits of knowledge On this map here we have a beautiful manuscript map of the Ali River in South America, which is in Seville in the Archivo Generale Indias made in 1663 and the river is in Peru and we have these two cartouches in the upper corners that list place names.

The one on the left talks about Tierra descubierta land that has been discovered. The one on the right is about tierra de Noticia or land about which he has reports. So he's distinguishing between two types of place names those from land that he has actually discovered and those from land that he only has reports about. So again, a very forthright distinction between what is certain, what the cartographer is confident about and what he's not confident about. In some cases we can really only appreciate uncertainty by looking at a whole corpus of maps.

And we're going to look at several early maps of South America from the 16th century and see that there's really almost no consistency in depicting the shape of South America. So while when we look at each map, again maps have this aura of veris militude. While we look at each map, we might think, well, the cartographer is confident about the shape of South America, but when we look at several maps together, we can see that South America has almost any shape one might wish and thus we can deduce that really there was almost no certainty about its shape.

So here is the world map by Juan de La Caza from about 1500. Just to orient ourselves a little bit. Here is Africa and here is South America. So it's shape is not very similar to what we now know it to be. Here is Giovanni Contarini's, world map of 1506. Again, here's Africa, here is South America. So it has a very different shape even taking into account the difference in projection between the two maps. Here is Martin Voltimiller's world map of 1507 here is South America. Again, even taking into account the difference in projection, it has a completely different shape.

Francesco Roselli's world map of about 1508. Again, the continent has a completely different shape. Here we have another map by Francesco Roselli, the same cartographer made in about the same year. And South America has a different shape, different not only than all the other maps we've looked at thus far, but also different than Roselli's own map. The modern world map in the 1513 edition of Ptolomy's geography. Again, south America has a different shape. Pietro Coppos world map of 1524. Again, just to orient ourselves a little bit, here's Africa and here is South America. A completely different shape.

Juan Vespucci's world map of 1526. Again, south America has a very distinctive shape. Even taking into account I think we're to understand that the cartographer doesn't want to commit to the western coast of the continent. But even taking that into account, we have this almost perpendicular coast on the East. Sebastian Munster's world map of 1532. Again, almost any shape you can imagine. Jean Rotz's world map of 1542. Here we have the eastern part of the continent as a huge island. Guillame Brouscon's world map of 1543 where we have an enormous peninsula jutting westward. Sebastian Munster's world map of 1550. We saw another map by Sebastian Munster earlier that had a completely different shape for South America.

Here we have a huge gulf in the west and a huge peninsula jutting east. So we just saw another map with a huge peninsula jutting west. Now we have one jutting east. So really almost any shape you can imagine, there's a map of South America that shows it. Having that shape, and again, looking at each one of these maps, this aura of verisimilitude might convince us that the cartographer knew what he was depicting. But looking at all these maps together, we see that that is certainly not the case. And Tony Campbell has referred to another similar case, which is Maps of Japan. He has remarked that "perhaps the early mapping of Japan shows greater variations than that of any other region." So this would be another case where Japan has many, many, many different shapes in early cartography. So another expression way of realising that the cartographers were uncertain about what they were depicting.

Another method that cartographers had for dealing with uncertainty was presenting two options and leaving it to the reader to decide what to do about them. Here we have the title page of the 1513 edition of Ptolemy's Geography, the maps in which were made by Martin Waldseemuller. This edition contains the 27 traditional Ptolemaic maps, which is to say one world map and 26 regional maps and 20 modern maps that are based on an entirely different cartographic tradition that of nautical charts. Both sets of maps contain a world map and more detailed maps of all the other parts of the world. So here we have the tome world map and the modern world map. Again, both in the same edition we have the Ptolemaic map of the British Isles and the modern map of the British Isles. And as we can see they are very, very different.

The Ptolemaic map of North Africa and the modern map of North Africa. Again, their shapes are very, very different. So Martin Waldseemuller really presents two parallel cartographic universes and he writes that the second part is of the more modern explorations in 20 plates as a kind of supplement to antiquity now obsolete. But that raises the question if the first part is obsolete, if the Ptolemaic maps are obsolete, why does he include them? And when and how would one use the Ptolemaic maps? And Martin Waldseemuller was really stuck in uncertainty between his respect for Ptolemy on the one hand and his recognition that more recent nautical charts were much more accurate than Ptolemaic maps.

Another very interesting case of the cartographer offering two options and leaving it to the user or the reader to decide which to use is in this doppia or double nautical chart from 1617 by two Italian cartographers, Placido Caloiro and Joan Oliva. So it's called a double chart. It really has three charts within it. First one of the Atlantic coast of Europe and then two of the Mediterranean. So here's the map of the Atlantic coast because it contains within it three maps. It's quite complicated, one has to say. But here is the map of the Atlantic Coast and then these two charts of the Mediterranean and many details are repeated from within these two charts.

So here we have the Strait of Gibraltar. Here we have the Balearic Aric Islands. Here we have the Boot of Italy, Cyprus, and Golgotha. So why are there two charts of the Mediterranean on this chart? Well, there is an important difference between them. So if we draw a line from Cyprus to the Strait of Gibraltar, we see that they, they're at different angles. And what that means is that the top chart is a traditional nautical chart and the bottom chart has been corrected for magnetic declination. So the cartographer is offering both a traditional chart and an updated chart corrected for magnetic declination.

And evidently the cartographer is uncertain which the user will prefer and thus offers both. One of the great challenges in making a map is reconciling different sources and that is a source of uncertainty trying to reconcile different sources and I think this map is a wonderful illustration of that difficulty. So this is Guillaume Delisle's preliminary study for a map of Egypt, Nubia and Abyssinia made in about 1725. And as you can see, the map is very, very dense with the cartographers notes, compiling information from different sources and trying to reconcile them. So here we have the Red Sea here we have the eastern coast of Africa, and then we have what I've marked in blue, a different coastline that Delisle considered but rejected. So he's compiling information from different sources in this map, weighing the different sources against each other and then deciding how to proceed.

We can zoom in, we can see both that the two different coastlines and the density of his notes recording information from the different sources he was consulting. And if we zoom in at the top of the map, he's actually used a colour scheme to distinguish different sources. So the texts in red come from classical sources and the ones in black from more recent sources. So this example gives us an idea of the complexity of trying to weigh different sources against each other and come up with a final product. In some cases cartographers confessed their inability to make a map because of uncertainty. And we have a few examples of this type of map. So this is Didier Robert de Vaugondy's Carte de la Californie, map of California, from 1770. But I would suggest that it's actually not a map of California, it is not a successful mapping of California.

What he does is he reproduces five different maps of California that don't agree with each other and he throws up his hands and says, I don't know what to do, so I'm just reproducing these different versions of the truth. So first he reproduces a copy of a manuscript map by Pecci made in Florence in 1604. Then a map by Nicolas Sanson from 1656 that shows California as an island. So this off repeated myth that California is an island third, a map by Guillaume Delisle from 1700 here California is not an island. Fourth, a map by Eusebio Kino from 1705 who debunked the myth that California was an island.

And finally the fifth is a copy of a Jesuit map from 1767. So some of these maps show California as an island, others do not. He gives us no basis for choosing between them and evidently he was unable to choose between them. So he's really declared his inability to make a map of California because he had no good basis for distinguishing for choosing among these different models. We see something very similar in Alexander Dalrymple's charts of the Malabar coast comparing the various published and manuscript charts from Mangalore to Bombay from 1789. So notice that he says charts plural and he's done exactly the same thing.

He was in London, he's talking about the coast of India and he had in front of him various different maps and he had to admit that he didn't have a good way to choose which was correct. So he reproduces five of those maps. So first the coast, according to the English cartographer, John Thornton from 1703 second the coast according to an old manuscript chart by the English cartographer, Augustine Fitzhugh the coast according to an unidentified Dutch manuscript chart.

The coast according to a chart by the Dutch cartographer Van Keulen, the coast according to the French cartographer Mannevillette from 1745 and then the same cartographers later map of 1775. So he reproduces these six maps and again offers us no rationale for choosing one over the other. And he was unable to find a rationale to choose one over the other. And he addresses this issue in his general collection of nautical publications. He writes, whoever knows anything of making charts from a variety of materials must know that it is impossible to reconcile those materials perfectly indeed, it often happens that they're totally contradictory. Where I find disagreement in particular charts, I have thought the best way was to engrave both when I had nothing to enable me to decide on the merits of either. So he's expressing here textually very clearly what we can see from his map that he had no good basis for deciding among these various different depictions of that coastline. So he just reproduced six of them.

I'll close with a few words about mapping uncertainty about Australia, and first I'll look at Nicolas de Fer's world map of 1694, which we see here. And I'll zoom in just to show the title car and then just to show how conscious the cartographer was of issues about uncertainty, we'll zoom in on part of Africa and just south of the sources of the Nile. He writes, it was thought better to leave this space empty than to fill it with unknown or imaginary details. So rather than depicting something he was not certain about, he's content to leave blank space on the map. And this is something we saw in Claudius Ptolemy earlier, his willingness to leave most of the globe blank and only depict the parts that he was confident about.

Zooming out again, we can see that he uses dark lines to indicate coastlines that he is certain about and lighter lines for coastlines that he's uncertain about. And if we zoom in we can see that he's expressing his uncertainty about the coasts of New Holland, Australia and New Guinea as well. And we can see the contrast between the lighter coastlines and the darker coastlines in the islands of Southeast Asia. And we'll end with Emmanuel Bowen's complete map of the southern continent surveyed by Captain Abel Tasman in 1744.

So we see some uncertainty here in incomplete coastlines, but much more dramatically in this huge hypothetical continent joining New Guinea, Australia, Tasmania, and New Zealand. And we also see uncertainty expressed in an interesting way when we look at the descriptive texts in this part of the map here, for example, we zoom in and read it is also requisite to observe that the country discovered by Ferdinand de Quiros lies according to his description on the east side of this continent, directly opposite to Carpentaria, which if attentively considered will add no small weight to the credit of what has been written about that country and which has been very rashly as well as very unjustly treated by some critical writers as a fiction.

Whereas it appears from this map of actual discoveries that there is a country where Ferdinand de Quiros says he found one. And if so, why may not that country be such a one as he describes? Well, when anyone asks you a question on a map, there's certainly some uncertainty lying behind that question. And the phrasing here is he's trying to persuade us. And of course if he's trying to persuade us, he's not certain and we can see something similar in the second text here.

He says, "if Peru overflows with silver, if all the mountains of Chile are filled with gold and this precious metal and stones much more precious are the product of Brazil, this continent enjoys the benefit of this same position and therefore whoever perfectly discovers and settles it will become infallibly possessed of territories as rich, as fruitful and as capable of improvement as any that have been hither to found out either in the East Indies or the West". And again, if anyone uses the word infallible, they're trying to convince you of something and behind that effort to convince there is uncertainty.

So to conclude, most early modern cartographers do not address uncertainty at all. Preferring not to diminish their maps, prima faci credibility and trustworthiness. Some cartographers do list their sources, but they rarely discuss the relative reliability of those sources leaving us to guess about their criteria. So some cartographers include on their map a list of the sources that they used, and in some cases it's possible to deduce which elements on the map come from which sources, but they typically don't tell us how they made the decision to trust one source over another.

A few cartographers like Pierre Desceliers, John Smith and Nicolas de Fer used signs to distinguish certain from uncertain geography. And in the 18th century when cartographers were more conscious of conflicts among their sources, some in effect declined to make a map instead merely reproducing the conflicting sources among which they had no good evidence to decide. So that sort of failure to actually make a map because of uncertainty is really the ultimate indication of respect for the truth. Thank you very much.

Jo Ritale: Thank you Chet for that fascinating presentation. Now we do have some time for questions, so if you can please wait for the microphone to come to you before asking so that everyone can hear your question. So yes please, if anyone does have a question, put your hand up.

Audience member 1: Hello. Thanks for that presentation. It's very nice. I'm just wondering if you have any insights into where it may be more a personal choice of the cartographer versus maybe societal political pressures from patrons, for example, maybe there's certain cultures I guess that are more comfortable with uncertainty, that kind of thing, or if there are any kind of pressures to not kind of indicate uncertainty, that kind of thing.

Chet Van Duzer: There was probably more societal pressure about uncertainty in I would say the 17th and 18th centuries, particularly when the titles of maps contain words like exac in Latin, so most exact or most precise. And the repetition of words like that newest, most accurate in map titles certainly indicates that the marketplace valued accuracy and clarity and certainty. So that would be one pressure that I can think of on cartographers to treat their sources carefully and make an effort to weigh them against each other accurately and produce the most carefully weighed map they could.

Audience member 2: Thank you for a great talk. I wonder if 4 or 500 years ago people cared much whether a map was accurate or not. Are we wrong to assume they were pursuing verisimilitude? I suspect they were probably after excitement and interest and the more extravagant the shape, the more interesting it was.

When you come to Dalrymple, I think Dalrymple was covering his backside. He was the cartographer for the English East India company. There were ships sailing all the time along the Malabar coast. He didn't know which was the correct map. So we'll give you everything and it's not my fault if you run a ground. So in effect, precision has become more important than it once was just being interesting and entertaining might've been the way cartographers approached drawing South America 500 years ago.

Chet Van Duzer: Well, people were using nautical charts in the 13th and 14th centuries. And I would say that while with other genres of maps that were not being used for travel, an interest in elaborate decoration and even entertainment as you say, would have a larger place in nautical charts, lives were at stake. So with those maps at least there was an interest in producing something accurate, even if the abilities of the cartographers to do so were limited.

Audience member 3: I concur that it was a wonderful talk and a lot of work obviously done to prepare it. I noticed that it was, and it doesn't surprise me given where we are, et cetera, but that it was very, is there any Asian or maybe Arabic sources that are of either like or dislike that have a point of comparison or difference that is material to what you've done?

Chet Van Duzer: That's a great question. I'm trying to think about. So there are certainly, for example, Islamic geographical texts that talk about accuracy, but I'm not coming up with cases in maps, for example. I don't find anything in Islamic or Chinese cartography that's similar to the Dopia map. There are, for example, the 13th century manuscript, the book of curiosities at Oxford, which is an atlas of Islamic maps. There's a separate map of the Indian ocean and there's a world map and the two don't agree with each other very well at all. But that doesn't seem to have concerned the cartographer making that atlas as far as I recall. I'm trying to think. It's not, the atlas doesn't just consist of maps, it is also text, but I'm not remembering whether there's any discussion of those differences in the text. I don't think so, but I'm not sure.

Audience member 4: It's always interesting to see the different perspectives and how that shifts in time. I noticed you didn't go back as far as the map [unclear], but started in the early modern. Relating to one of the earlier questions, who were the audiences for these maps? So you've talked about nautical charts being used in anger by people actually navigating the seas, and some of these maps were certainly for interest. How do you see the different recipients panning out? What was the proportion or what kinds of maps were bought by what kinds of people?

Chet Van Duzer: It's a good question, a broad question. So it's hard to come up with an entirely satisfactory answer for, but one point worth making is that the makers of nautical charts we're serving two very distinct markets. So there are very plain nautical charts on decorated nautical charts, and that's the type that would actually have been taken to see and used in navigation. They also, the same cartographers made elaborately decorated nautical charts with gold leaf and all the images of sovereigns and sea monsters that one could wish for. And ironically, it's precisely the nautical charts that do have sea monsters depicted on them that would not have been taken to sea and those elaborately decorated charts would not have been taken to sea. So it's two very distinct audiences. I'm trying to think how else I can provide some useful answer to your question. You are more interested in [unclear], is that correct?

Audience member 4: No, I was thinking about this kind reflects the previous, that the same cartographer was producing practical maps and also for a different audience producing decorative maps.

Chet Van Duzer:Yes, that's right. I will take this opportunity to say that there are a few cases where the car tographer does talk about weighing the virtues of different sources. Fra Maro in his spectacular world map made in the middle of the 15th century, it has 3000 long descriptive texts on it. So he had space to go into detail and in some cases he does talk about the advantages of some sources versus others, but at that time very few other cartographers were doing that. I

Audience member 5:Thank you very much for your interesting talk. Do you know the nationality of Ferdinand  de Quiros and did he give a name to the landmass which later became Australia?

Chet Van Duzer: I am not remembering, I believe he was Spanish, but I'm not remembering what name he gave to the landmass. I'm sorry.

Audience member 6: I'm interested when the academic understanding of maps and the like came into being a field and stuff, and it gets to that whole question of historiography and historicity and stuff and how have you done that and how has that particular field looked at that particularly difficult set of questions?

Chet Van Duzer: So when did the history of cartography become the history of cartography?

Well, it's a very interesting question. The word cartography itself is a later invention than one might think. But there is a, I'm trying to remember, I think it's a 16th century atlas or 15th century atlas that reproduces several nautical charts by earlier cartographers in one volume. And I guess it's not exactly the history of cartography, but it's showing an interest in the history of cartography. It's showing an interest in comparing early charts. So that's the 15th century. And there are historical maps that were made in the 16th century.

So what I mean by historical maps are a cartographer intentionally producing a map that shows an earlier state of knowledge. So there's an Italian cartographer Baptiste Engese who in about 1540 or 1550 made a chart that reflected European knowledge at the very beginning of the 16th century in about 1503 and that, and he made other historical maps as well, and that shows a strong interest in the development of geographical knowledge over time. So he wasn't writing a history of cartography, but he was producing maps that illustrate the development of cartography for you.

Audience member 7:
Thank you. This is a sort of follow up to that. Are you aware, I mean I know it takes enormous amount of capital investment and years and years to make a map. Are you aware of anybody doing a second or third edition of their making an improvement on their first go?

Chet Van Duzer: Yes. I once gave a talk about, so these are not additions, but they're manuscripts. We talk about manuscript maps of Africa with corrections, and these go back to I think the late 15th and 16th century. So we see maps of Africa that were corrected if not immediately, very soon after they were made. And in fact, going back to Framaros mid 15th century world map, if one looks closely at it, he made a number of additions to it. It has all these, I think 3000 descriptive texts and many of the marine cartouches, if you look closely, some of those cartouches are pasted on to the map. So that shows him adding to and revising the map when he made it. So there was this, yes, there were improvements made even in the 15th and 16th century.

Audience member 8: So that would apply. There's a flow of correspondence letters from Mariners to the mapmaker trace.

Chet Van Duzer: That is a very good question. So how was it that Mapmakers received their information? And we have almost zero information on that. There is one nautical chart from 1402 in which there's a long text in which the cartographer talks about receiving new information. But it is surprising and a little disappointing that we don't have more cases like that, more. We have no correspondence where early cartographers say that they received a letter and this letter revealed that the shape of this peninsula is actually different. And I can only think of one early nautical chart that has an annotation on it where the cartographer says, I depict this island as I saw it. And we might hope for more of that, particularly as we know that at least some makers of nautical charts were themselves sailors. But for whatever reason, very, very few annotations like that appear on maps.

Jo Ritale: We got, oh, we've got more questions. Okay, one more question, I think.

Audience member 9: Thanks for that. Just picking up on that last question, response was one of the real challenges for Mapmakers at this time, the imposition of survey technology, including the reliance on things like dead reckoning for estimating longitude. And whenever you've got a first chart of the new coast, he told you something was there, but it was almost certainly wrong in some particulars.

Chet Van Duzer: I'm sorry. You're asking whether, well,

Audience member 9: The extent to which part of the cause of uncertainty was the imprecision of navigational and surveying technology?

Chet Van Duzer: Certainly, yes. The difficulty of determining longitude was a huge problem. And one can see when better methods for determining longitude were developed, maps changed accordingly. And in maps of the Indian Ocean, I think it was in 1684, the French sent a voyage to Siam and one of the missions of the voyage was to determine longitude in specific spots. And they did so successfully and that changed the longitude of those locations by, in some cases 20 degrees. So when accurate methods for determining longitude arrived, they certainly had their effect.

Jo Ritale: Okay, thank you again for that wonderful talk and also thank you to the audience for those really fascinating questions. And I'm sorry that I am cutting you off now. This brings our event tonight to a close, but I hope you all have a new appreciation for our early map makers and I guess the challenges that they had in the work that they did. And I'm sure that no one here will take Google maps for granted again, except maybe if it steers you in the wrong direction. But anyway, thank you and goodnight.