The invisible tracks that have shaped the world

Summary

History Extra Podcast: "The Invisible Tracks That Have Shaped the World"

Release Date: November 21, 2024

---

Introduction

In this episode of the History Extra Podcast, host Eleanor Evans engages in a compelling conversation with Dr. Sara Caputo, an affiliated lecturer at Cambridge University. They delve into Caputo's insightful book, Tracks on the Ocean: A History of Trailblazing Maps and Maritime Travel. The discussion explores how the seemingly invisible lines drawn on maps have profoundly influenced global history through power, conquest, and exploration.

---

The Concept of Tracks on Maps

Dr. Sara Caputo introduces the central theme of her book: the "tracks"—the lines on maps that represent voyages and movements across the world's oceans. She explains:

"The tracks I'm talking about are these imaginary lines that we leave behind on our maps when we think about ourselves in the world... but in reality end up leaving on the world, too, by sheer repetition and force of conviction."
— Sara Caputo [02:47]

Caputo challenges the taken-for-granted notion of representing journeys as lines on maps, highlighting that historically, travel was described verbally rather than graphically. She references the hodological vision—an immersive, path-based understanding of movement prevalent in the ancient Mediterranean and Middle Ages.

---

Historical Evolution of Map Tracks

The conversation traces the evolution of mapping journeys from individual verbal descriptions to the graphical tracks familiar today. Caputo notes:

"In the ancient world... people didn't use tracks... they were describing where you've been in a more embedded type of vision."
— Sara Caputo [04:04]

She identifies the 16th century as a pivotal period when Iberian navigators began charting their oceanic voyages with tracks, possibly influenced by East Asian mapping traditions. The advent of astronomical navigation made it feasible to plot more accurate tracks, transforming individual journeys into symbolic representations of exploration and imperial ambition.

---

Tracks and Empire Building

Caputo elaborates on how tracks became tools for empire-building and propaganda. By drawing lines across oceans, explorers could symbolically claim territories and assert dominance. She explains:

"By drawing a line, you can claim a stretch of the sea that is supposedly unclaimed... it becomes a really powerful tool of imperial propaganda."
— Sara Caputo [11:33]

This practice not only served legal and political purposes but also shaped public perception and national narratives. Caputo cites the debate between Hugo Grotius and John Selden over the freedom of the sea, illustrating how map tracks influenced international maritime laws and territorial claims.

---

Public Fascination with Tracks

The episode highlights the public's fascination with navigational tracks, using the example of James Cook. Caputo recounts an anecdote where Cook drew a track of his voyage on a book at a social gathering, which became a treasured artifact due to its symbolic significance:

"A track drawn by Cook's own hand had this power over the 18th-century public... like keeping up with celebrities today."
— Sara Caputo [17:18]

She emphasizes how tracks simplified complex voyages into easily understandable visuals, making them accessible and captivating to the general populace. This accessibility transformed tracks into symbols of adventure and national pride.

---

Tracks as Highways and Their Environmental Impact

Moving into the 19th century, Caputo discusses the transition of tracks from individual voyages to solidified maritime highways with the advent of steam liners. These repeating routes became the backbone of global trade and migration, reinforcing imperial connections. She observes:

"With increasing transport facilitated by these liner companies... the steamship companies give away blank charts of a world where a passenger can draw their track as they go along."
— Sara Caputo [25:39]

Furthermore, Caputo touches on the environmental consequences of these maritime tracks. She explains how ship tracks—linear pollution created by vessel emissions—have become a literal manifestation of human impact on the oceans:

"Today the term ship track actually refers to a type of cloud that is created by human activities... It's a form of linear pollution that is left behind by vessels."
— Sara Caputo [25:49]

This duality underscores how tracks, once symbolic, have tangible effects on the natural world.

---

Transition in Map Representation

The discussion concludes with an exploration of how map aesthetics evolved alongside the technological advancements in navigation. Early maps often featured sea monsters and elaborate illustrations, reflecting the fears and myths surrounding the unknown oceans. Caputo notes:

"In early modern maps, we start by having all of these drawings of monsters... they just say, we've been here, let's plonk this ship in the middle of this sea."
— Sara Caputo [28:36]

As mapping technology advanced, the focus shifted to scientific accuracy, stripping away decorative elements to present a more objective view of the world. However, Caputo cautions that tracks continue to impart narratives and perspectives, just in a more refined language.

---

Conclusion

Eleanor Evans wraps up the episode by summarizing the profound influence of maritime tracks on historical narratives, imperial ambitions, and environmental landscapes. She encourages listeners to explore further by reading Tracks on the Ocean and other related episodes focusing on land borders and their historical significance.

"People have been drawing lines on maps as long as there have been maps to draw on... If you're curious how land borders have shaped the course of history, then be sure to check out our episode with John Elledge."
— Wendy [29:56]

---

Key Takeaways

1. Tracks as Symbols: The representation of voyages as lines on maps emerged in the 16th century, transforming verbal descriptions into symbolic visuals that facilitated imperial claims and public engagement.

2. Empire and Propaganda: Tracks served as tools for asserting dominance over unexplored territories, influencing international maritime laws, and shaping national narratives.

3. Public Engagement: Simplified visual tracks made complex voyages accessible and captivating, fueling public fascination and national pride.

4. Technological Influence: The advent of steam liners and advanced navigation solidified tracks into consistent maritime highways, reinforcing global trade and migration patterns.

5. Environmental Impact: Modern ship tracks represent the tangible environmental footprint of human maritime activities, highlighting the ongoing relationship between navigation and ecological change.

6. Evolution of Maps: From embellished early maps to scientifically accurate representations, the evolution of mapping reflects broader shifts in perception, technology, and societal priorities.

---

Further Exploration

For those intrigued by the themes discussed, Tracks on the Ocean by Sara Caputo offers an in-depth exploration of maritime maps and their historical significance. Additionally, the History Extra Podcast features an episode with John Elledge that examines how land borders have influenced historical events, providing a comprehensive understanding of geographical demarcations in shaping human history.

---

This episode was produced by Daniel Kramer Arden.

Transcript

[Wendy]

This is Wendy from Science Versus. This month our friends at Ford are the presenting sponsor of Science Versus. If you're curious to learn more about things like electric vehicles, Science Versus is a great lesson. We dive into topics like how beavers are helping the fight against climate change, what the greenest way to die is, and what a 100% renewable future looks like and more. Listen to Science Versus on Spotify, brought to you by Ford.

[Ryan Reynolds]

Ryan Reynolds here for I guess my hundredth mint commercial. No, no, no, no, no, no, don't. No, no, no. I mean, honestly, when I started this I thought I'd only have to do like four of these. I mean it's unlimited to Premium Wireless for $15 a month. How are there still people paying two or three times that much? I'm sorry, I shouldn't be victim blaming. Here, give it a [e-mail] save whenever you're ready. $45 upfront payment equivalent to $15 per month new customers on first taxes and fees extra speed slower above 40 gigabytes cd tails this episode is brought to you by United Airlines. When you want to make the most of your vacation, book with United. They're an airline that cares about your travels as much as you do. United is transforming the flying experience with Bluetooth connectivity, screens, power at every seat, and bigger overhead bins to help fit everyone's bag. And with their app, you can skip the bag check line, get live updates and more. Change the way you fly. Book your next trip today at united.com want to shop Walmart Black Friday deals first Walmart plus members get early access to our hottest deals. Join now and get 50% off a one year annual membership. Shop Black Friday deals first with Walmart Plus. See [e-mail].

[Wendy]

Welcome to the History Extra Podcast. Fascinating historical conversations from the makers of BBC History Magazine. Each ocean voyage through history has laid down a track that tells a story. These invisible pathways across the seas can reveal how the world has been shaped by power, conquest and exploration. Dr. Sara Caputo explores how lines on a map can have consequences in the real world in her new book Tracks on the Ocean and Eleanor Evans spoke to her to find out more.

[Eleanor Evans]

Sarah, thank you so much for joining me on the History Extra Podcast to talk about your new book Tracks on the Ocean.

[Sara Caputo]

Thank you. It's my pleasure to be here.

[Eleanor Evans]

Could you introduce for our listeners then this concept of the tracks that you're talking about and bring them into this idea that you've written about in this book? How can we understand that Tracks are laid on water.

[Sara Caputo]

So the book is about the journey tracks that we leave on the world. So this idea that we imagine our movement across the world as a line. And my question was, where does this idea come from? Because we take it for granted, right? When we open any map app or Google that, our trip, our movement is represented as a line on the world. But in reality, this is not a natural way of imagining our movement across the world. And I think looking at the past really helps to put this idea in context. Where does it come from? How did it begin? And that was my guiding question for the book. So the tracks I'm talking about are these imaginary lines that we leave behind on our maps when we think about ourselves in the world, but in reality end up leaving on the world, too, by sheer repetition and force of conviction, because ideas are really powerful, and they can have a strong impact on the world and on the environment.

[Eleanor Evans]

So these tracks and their legacy, as you say, there's a moment when they come about, and I'm sure we'll get to that in a moment. But before you see these tracks emerging, before they start to become more commonplace, what were some of the other ways that people understood travel and space before these tracks began to appear?

[Sara Caputo]

So that is very interesting because it's not necessarily just a neat before and after. These are tools that we still have and we still use for moving in the world. It's just about which ones are more prevalent before or after. So in the ancient world, as far as we know, people didn't use tracks. We haven't got any maps or charts that show an individual journey as a line from the ancient Mediterranean and then up into the Middle Ages. The way in which they described and represented their journeys was verbal. So there would be descriptions of the different stages of a journey that were either textual lists or, we imagine, potentially passed down orally. And you can see how this is very different from looking down on the world as a flat surface and imagining your line across it. It's a more embedded type of vision. And classicists have spoken of what they call hodological vision. And hodos in Greek means path. This is a path, but the path in the sense of a path that you walk, you're immersed in the world. So when you are describing where you've been or where you're going, you're not drawing a line. You're saying, oh, you go straight in that direction for two days, and then you'll see a mountain on the right, and then you keep going. And then there's a Little valley. And so you imagine the world and you inhabit it, and the world is central to your description of where you've been. Whereas drawing a line, you're actually, in a way, enforcing your own story onto the world. You're marking the world rather than following its structures. And you can see I was talking about the before and after. In reality, we still use this kind of embedded vision. It's only that we use it for places we're familiar with. If I have to go to the shops from my house, I don't need a track because I know this place. And if I had to tell a family member how to get to the shop, I wouldn't necessarily draw a track. I would just say, well, you keep going down the road, and then there's a little pink church, you turn right, and then there's a bakery. You go past the bakery. So you see, that kind of way of living in the world hasn't disappeared. It's just that with global expansion, you can't possibly know every single place that well or take the time to understand it well and live in it in that kind of way. And so the track and as an abstraction, becomes a really, really important tool in a way, assisting these imperial enterprises, particularly across vast expanses like the oceans, where really, unless you know them very well, you can't see a path at all. And you have to find another reference system. So my theory is that the sea was really central and that maritime exploration in particular was really central. The first tracks, like individual journey tracks, that I have found appear in the early 16th century, right at the time when Iberian navigators were going out into the ocean and going south of Africa and then into the Indian Ocean. And I suspect they might have been influenced by some mapping traditions in East Asia, where they did represent tracks on water. But they weren't individual tracks. They were more like routes, roads. So there was this convention of drawing lines of water, which didn't necessarily exist in the West. The individual lines then, are very much connected with the idea of astronomical navigation at sea. On land, you don't really need to draw a journey because there is a path. So people had been able to get by with that kind of descriptive, embedded, directional structure type of travel that we were talking about. And they had been able to get by with it even when navigation was coastal, because there are always landmarks in sight. And so you can tell other navigators, you keep going for two days, there's that promontory, you keep going, and then there's those shallows, and then you'll See a steeple in the distance, etc. What you can't do is use that kind of method when you're out at sea, and when you're out at sea for days and days and days on end, the kind of length of navigation that you would expect if you're venturing out into these still unknown oceans. And at that point, then astronomical navigation becomes a very useful tool. And astronomical navigation increasingly gets tied up with charts and with the cartographical representation. So when the cartographical representation takes over, that's when the track really also has a field day, basically. And we do have charts for the Mediterranean in the Middle Ages, I should add, the Portulan charts, and potentially navigators pricked their route on them, but there's no surviving evidence of that practice. Whereas these blazing lines of oceanic explorers from the 16th century immediately become a convention that is used for representing imperial voyages.

[Eleanor Evans]

So these lines, these journey tracks, become a visual representation, as you say, a graphic device to show where people have voyaged, where people have gone. You already touched on it that they evolve in terms of their accuracy. I wonder if perhaps we could pick up on a track's evolution over a certain period.

[Sara Caputo]

So the interesting thing is that tracks, by their nature, once they're drawn, they don't evolve because they're a story that has been told in a certain way. And so more than evolution within a single track, what we see is evolution in the types of tracks that get drawn. In the early 16th century, the track of the first circumnavigation of a world by Magellan and Juan Elcano in 1519-22 gets drawn as this blazing trail across the world. But the reality is that because Magellan and Elcano didn't have a clear idea of where they were at any given point, because the navigational techniques to pinpoint that hadn't really evolved yet. That track is entirely symbolic. It's not meant to be accurate. It's representing this image of the voyage. And in fact, in different maps, it looks completely different. There are lots and lots of different varieties. Fast forward to the 18th century and the voyages, for example, of James Cook. James Cook was trying to pay a lot of attention to pinpointing exactly where he was, because his expeditions had the charting of the oceans as an important component of the objectives that were set out. And so he tried to pinpoint his position accurately. And so what we have is an actual daily record of where the ship was at any given point. And so those tracks are a lot more accurate. And then they get reproduced more accurately, again in inverted commerce, because there is a solid base there. So in maps of Koch's journeys across the world in all languages, if you compare the tracks, they actually look almost exactly the same. And this is the change. Now, what I'm saying here is that there is more of an attention to accuracy. I'm not saying that these tracks ever are completely accurate. As scientists know very well, perfect accuracy is impossible. They're still relying on measurements, and measurements can be more or less precise, but they can never really, really reproduce reality to the millimeter.

[Eleanor Evans]

So you've written in your book that the most obvious narrative that Trax told was one of empire building. I wonder if we can explore this idea a little bit more.

[Sara Caputo]

There is a symbolic dimension to this, the idea of appropriation of occupation. By drawing a line, you can claim a stretch of the sea that is supposedly unclaimed, that has supposedly never been crossed before. So it's a type of priority claim that goes hand in hand with the notion of discovery, right? And then this kind of way of thinking acquires legal dimensions. And in fact, in the 17th century, there's this big, really famous debate between Hugo Grotius on the one hand and John Selden and others on the other. This debate about the freedom of a sea. Can the oceans be partitioned and apportioned to different countries, just like territory on land? And Grotius says no. He says it's completely ridiculous that just by drawing a line across the water, you claim that now all that stretch of water is yours. Whereas the people who defend the idea of a closed sea and the idea that you can actually claim water just as you can claim land will say, well, there are ways of marking water. And so this idea of marking water with your own personal claim to it has these super important dimensions, both like culturally and in terms of mindset and kind of acquisitive mindset, and legally, because that transfers into the language that states use to discuss their claim over certain territories.

[Ryan Reynolds]

This episode is brought to you by Atlassian. Atlassian makes the team collaboration software that powers enterprise businesses around the world, including over 80% of the Fortune 500. With Atlassian's AI powered software like Jira, Confluence and Loom, you'll have more time to do the work that matters. In fact, Atlassian customers experience a 25% reduction in project duration per year. Unleash the potential of your [e-mail] Atlassian the holidays are here at the Home Depot, so let's get to decorating. Find your perfect tree in our huge assortment of shapes, sizes and styles. Like the easy to assemble Jackson Noble fir with pre lit branches perfect for styling with all your favorite ornaments. Or the flock starry light Frasier fir with over 1900 pre lit memory wire branches that keep their shape. So it's ready right out of the box. Ooh, find the perfect tree now at the Home Depot. Okay, I have to tell you, I.

[Eleanor Evans]

Was just looking on ebay where I.

[Ryan Reynolds]

Go for all kinds of things I love. And there it was, that hologram trading card. One of the rarest, the last one I needed for my set. Shiny like the designer handbag of my dreams. One of a kind. Ebay had it. And now everyone's asking, ooh, where'd you get your windshield wipers? Ebay has all the parts that fit my car. No more annoying, just beautiful. Whatever you love, find it on eBay. EBay.

[Eleanor Evans]

Things people love at the moment we've talked about tracks as lines on a map, but you write in your book about the idea that there are tangible tracks also left on places that western navigators visit, which obviously are very tied up in this notion of empire building. Could we go into some of those examples?

[Sara Caputo]

It's quite interesting how celebrity and exposure more generally also make you accountable. The more you are visible, the more exactly what you've done comes into the limelight. Right, so this is a bit what happens with these tracks, even at the time, and then subsequently from a historical point of view, if you want to use them to investigate what exactly these navigators did and how their journeys worked. So at the time, for example, there was a lot of debate between the British and the French as to who exactly had introduced venereal diseases in Tahiti. And they tried to blame each other, except there was exact record of who had been there first, because all of these journals about describing the voyages had been extensively publicized. Right? So it was very difficult to deny that someone had arrived first, because that's exactly what they were trying to do, claim that they'd been there first. And I'll give you another example. And this is more directly related to the graphical representation of the track. When Matthew Flinders maps the coastline of Australia in the early 19th century, there's this voyage that he embarks on that is often described as this moment of high imperial endeavor. And the reality is that Flinders did what he could, but, like, his vessel was very leaky and really in a poor condition at the time when it left Britain, let alone by the time it got to the other side of the world. And the track actually captures that. So the Funny thing is that in these maps that celebrate the imperial consolidation of the appropriation of Australia effectively, there's this line that goes all around Australia, defining it for the British public. But if you actually measure that line, it shows you how slow this vessel was and how much it was struggling even with the best winds. So there's this paradox that these stories get soaked up by the track, and then the track can end up telling unintended tales, effectively to the extent that it mirrors what happened.

[Eleanor Evans]

So what you're giving us is a lot of historical context about how these tracks can tell stories and can give us more information than just a line on a map. You've talked about the idea of these explorers laying claim to their own tracks, cutting tracks across the globe, and how these tracks come to be associated with individuals, and especially in that visual, graphical way. Can you give us an example of when this has happened?

[Sara Caputo]

There's a really good example of this power that tracks have to tell a story, even to people who are not experts. And that involves James Cook again. So it's the winter of 1772, and he's just come back from his first voyage around the world, and shortly due to set out on his second voyage around the world. And he's at a soiree in the house of Charles Burney, who is really famous London musician and intellectual. And there's a copy of this book that is an account of the voyage of his French rival, Bougainville, another navigator, who's just circumnavigated the world as well, on a table there in Bernie's house. And Cook picks it up and starts talking about how this man hadn't been very friendly to another English navigator. There's a lot of gossip going on, and Bernie asks Cook to draw these stories on the map inside the book. And so Cook takes out a pencil and starts drawing a track there. And then now I have been trying to find this book. Burney's collections went to the British Museum and therefore should be in the British Library. A few years ago, I went to the British Library, called up every single copy they had of that book, which is many, and I was frantically opening them all and checking the map at the start, and then nothing. I couldn't find it. But it's there somewhere. So somewhere there is this book with Cook's track. And the reason why it's there is that Bernie was so enthralled by the way in which Cook had drawn it on the spot, like, in so scientific a manner, I'm quoting what he Said he used the term scientific, that he kept it, he fixed it with skimmed milk and then he just kept it as his treasure. So that really, I think, encapsulates the way in which these tracks were tokens of celebrity. In a way. A track drawn by Cook's own hand had this power over the 18th century public, which is the same as, like, keeping up with celebrities today, I suppose.

[Eleanor Evans]

Yes, they sort of did really capture public imagination at a certain point in the 18th, 19th century. How did they become to be such a source of fascination for the public?

[Sara Caputo]

The track really has disadvantage over other types of representation. It's clear and it's really simple and it's really legible. It's very easy to understand. So as these stories of imperial adventure all over the world started to capture the imagination of European publics at home, obviously you couldn't necessarily just give them a logbook with all the numbers, like the coordinates of where these ships had been. They wouldn't have meant much, but the track instead showed people where these ships had been. And so, in a way, it becomes a really powerful tool of imperial propaganda. And increasingly, as these stories, first with Drake in Britain, and then later on in the 18th century, with the wave of exploration of the Pacific in the second half of the 18th century, James Cook obviously is the foremost of these navigators. But similar phenomenon happens in France, for example, with the voyages of Bougainville or La Prouse. And Then into the 19th century, European publics get exposed to more and more of these tracks as print becomes more and more accessible and widespread. And I think we see the culmination in the Victorian period where there's this real explosion of popular, cheap, relatively cheap storytelling via the printing press. And I'll give you a really famous example here, which is the search for John Franklin. So John Franklin was this navigator that went out on an expedition to try and find a Northwest passage, so going from the Atlantic into the Pacific, going above the North American continent. And he set sail in 1845 and is never heard from again. And so three years later, the first expeditions are launched to try and find him and his two ships like Erebus and Terra. And over the following 10, 15 years, lots of other expeditions keep going out and trying to find these ships. And there's a lot of public debate about where Franklin has gone. And this debate is often conducted using maps, with a track of the ships and a track of the searchers. And there's even an enormous globe that gets mounted in Leicester Square at the same time as the Crystal palace exhibition in 1851. This monster globe, as they called it at the time, where you can climb up inside the globe and you'll see the track of Franklin. And then the idea, as it's put in the catalogue, is that any observer can then make up their mind as to what the right direction is to send these search expeditions. So the general public obviously has no understanding of the really, really complicated geography of the Arctic, has no real understanding of naval matters. But like, seeing the track clarifies the situation to them, at least to some extent, and gives them this notion that they are in control of what's happening. And so the track is a really good marketing tool, in a way, for ideas of empire and navigation.

[Eleanor Evans]

As you say, that truncated track gives a real stark evidence of what happened to Franklin and those vessels. You've also written about how over the course of the 19th century, though obviously, Franklin aside, a lot of these, well, beaten tracks, tracks did become more common highways. What's the process of these tracks upon water becoming firmer, if that's the right word to use.

[Sara Caputo]

It's quite an interesting process that really starts from the beginning, because the sea does have paths, even if we don't see them. And so we might be more tempted to claim them as our own discovery because they're not as visible as paths on land. But there are winds and currents to push especially sailing vessels into very specific routes. And these routes start being claimed by European powers as early as well, a few decades after the first voyages, because they are the most efficient known routes to get to imperial territories overseas. And so that is when they start solidifying. But it's not until the 19th century, and in effect, the introduction of steam liners, that these routes really become solid. Because the idea is that a steam liner can always tread and retread the same path, not worrying too much about winds and currents in theory. And therefore there's this idea that there's a reliability to these routes that makes them into highways, effectively channels of conveyance from one continent to the other, and increasingly channels the millions of people can use. I don't want to overemphasize the novelty of globalization. People have always traveled lots and lots of people have always migrated and moved across the oceans, even in the age of sail. But with increasing transport facilitated by these liner companies, and the term itself is interesting, these are steam lines, really. There's a solidification of the transport options. So at that point, they're not individual tracks anymore, but they come from individual tracks. They are there because someone has been through and then they get claimed both by countries and by individuals. So steamship companies are national. And they're very much involved in the imperial endeavors of their respective countries. And individual tourists who travel on these steam tracks draw their own tracks. So the steamship companies give away blank charts of a world where a passenger can draw their track as they go along in a way, pretending to be a navigator in inverted commerce. Like living their own adventure personally. On an apparently really impersonal highway of the oceans. So there's this structure that gets consolidated as more and more people use it.

[Eleanor Evans]

And in terms of the advent of this technology of steam liners, of eventually fuel powered liners, there comes a moment where these tracks do become physically visible.

[Sara Caputo]

Yes. So that is the obvious environmental side of transportation. The consequences of our movement across the world. And when I say our, I mean some of us. Obviously there's a small portion of the world's population that moves a lot. And there's a lot of people who never do. But obviously there are important environmental consequences of steam shipping on the ocean and on the sky. And the funny thing is that today the term ship track actually refers to a type of cloud that is created by human activities. It's a linear cloud. It's not a contrail. It's different from a contrail of airplanes. But it's similar in shape. And it comes from the effect that the sulfates emitted by ship engines have on existing clouds. So it's a form of linear pollution that is left behind by vessels. Not so much in the last few years. Because sulfur emissions in shipping have been cut down by international regulations quite recently. And then scientists are saying that actually that might cause in turn other problems. We are really entangled in this situation where any variable that we change at this point might actually affect global warming. But it's interesting that these lines become real in that sense. And they also become real in terms of the pollution left on the water. So for example, oil spills, when a ship is traveling quite fast, they do take this linear shape as well. And it's quite an interesting phenomenon. Because before the age of steam, apart from the old shipwreck, human travel over the sea wasn't really leaving that many physical marks. But from the 19th century onwards, we have really started transforming the water with our passage across it.

[Eleanor Evans]

So just to simplify where we've got to, we've gone from then the earliest tracks being laid being written on a map speculatively, with not as much information, to an age of navigation where these lines gain more navigational significance. To the advent of Greater technologies where these ships are actually drawing the tracks themselves. Is that a fair representation?

[Sara Caputo]

Yes, yes, it is. I mean, obviously I'm telling a long term story and there are lots of historical specificities at every step and there are other ways in which you could rearrange this story. But that is the trajectory that I see, that is the track that I see that I'm hoping to reconstruct in the book.

[Eleanor Evans]

It's such an interesting idea of how these conceptions of relationship to sea and the roots have changed. And if I can just give in my own favorite example quite early on from your book, where the tracks were surrounded by sort of little illustrations of sea monsters or creatures from the depths.

[Sara Caputo]

Yes, it's very interesting, this transition. So in early modern maps, we start by having all of these drawings of monsters and little ships, even that represent what's going on over the seas. So especially the monsters. There's a lot of debate among historians. They're often taken to represent the fear of the unknown. And the sea, what is it going to do to people who venture out into it, devour these explorers and the ships, in a way serve a similar function to what the imperial track will do later. They just say, we've been here, let's plonk this ship in the middle of this sea. And in a way it kind of signals presence and endeavor. And then at the same time as tracks start being used, we also see another type of way of representing a journey. So ships get drawn in a clear line of direction to mark the journey. And then that was a bit clunky and not as readable as the track. So it doesn't necessarily have much success as a graphical device the way that the track does. But like there's this transition between drawings and tracks. And then we think that our modern maps and charts have done away with all of these decorations and all of these narrative rubbish. They are objective, they represent the world as it is. Yes, but what about the tracks? They're doing the same thing, just in a slightly different language.

[Wendy]

That was Sara Caputo, affiliated lecturer at Cambridge University. Tracts on the Ocean, A history of Trailblazing Maps and Maritime Travel is published by Profile Books and is out now. People have been drawing lines on maps as long as there have been maps to draw on, whether for political, geographical and sometimes completely arbitrary purposes. And this isn't just overseas and oceans. If you're curious how land borders have shaped the course of history, then be sure to check out our episode with John Elledge and you can find the link to that in the episode description of this podcast. Thanks for listening. This podcast was produced by Daniel Kramer Arden.