The Figure of the Earth Voyages of Discovery

300 years ago, a group of men found themselves thousands of miles from home, fighting for their lives.

They had travelled halfway around the world, across unknown lands into hostile territory.

But these were no hardened adventurers.

They were bookish academics on one of the most important scientific expeditions ever.

Its outcome would fundamentally change the way we see our world.

But their mission would become an eight-year epic of obsession, betrayal and murder.

History is littered with explorers

who are driven by a desire for wealth and glory.

But the men on this expedition were different.

They were scientists,

and this was the first scientific expedition ever.

The ambitious mission was launched in 1735

to discover a fundamental truth about our planet...

..the true shape of the Earth.

I'm not short of ambition myself.

I've climbed on Everest,

and run countless expeditions in polar regions.

But even by my standards,

this French mission was an amazingly ambitious project.

And I've always had modern equipment and modern back-up and support.

These scientists didn't know what they were getting into.

Their three-year plan

involved sailing 10,000 kilometres from France to the equator...

scaling the Andes and crossing dense rainforest.

It was a bold plan to begin with

but it would turn out to be much more daunting than they could have imagined.

They'd be plagued by disease and death.

Instead of taking three years, it would take them nine.

But, for all that, they would make a series of chance discoveries that would have a profound impact.

From maps and medicinal cures,

to rubber goods and the metric system.

This is the story of their incredible journey,

carefully pieced together from their own journals.

"We sailed from La Rochelle in the month of May 1735,

"provided with passports from His Catholic Majesty Philip V,

"for the purpose of taking measurements next to the equator."

C'est tres bien, quand meme. C'est un des meilleurs de Paris.

Si on continue comme ca on va etre en retard.

Merci bien, Monsieur.

A team of men loaded their ship, the Portefait, with state-of-the-art scientific instruments.

And leading the expedition were some of France's greatest brains.

Pierre Bouguer, aged 37.

A mathematician who had been a child prodigy, and was made a Royal Professor at just 16 years of age.

Charles-Marie de la Condamine.

Aged 34.

A wannabe adventurer with four years' experience in the military.

And Louis Godin.

Ambitious mathematician and astronomer.

At 31, he was the youngest of the three,

but he'd appointed himself leader

on the grounds he'd suggested the expedition in the first place.

With their delicate scientific instruments and elegant attire,

these men were the very antithesis of rugged explorers.

Merci. ..Ne touche pas!

Je pense que c'est vivant! Oui!

Ca vient d'un des meilleurs fabricants en Paris.

Bien sur, bien sur!

Voila, Monsieur. Ah, Monsieur!

Vous etes prets? Oui, oui. Tres bien.

Messieurs, on est pret a partir.

The team had barely travelled beyond the boulevards of Paris,

and now they were heading off to the other side of the world.

The mission the French scientists were charged with was a huge one.

Nothing less than to measure the shape of the entire Earth.

For centuries, people thought the Earth was a sphere, a perfect ball floating in space.

One unusual measurement would change that notion.

When Louis XIV, the King of France, wanted a new map of his country,

he got the famous Italian astronomer Cassini to do the job.

Cassini noticed something really odd. Up in the north of the country

a degree of latitude was a different length

than a degree of latitude in the south of the country.

So this suggested something really shocking - that the Earth wasn't a perfect sphere at all.

So, Cassini's measurements led him to believe that the Earth was kind of egg-shaped.

And, suddenly, everyone came up with their version of the shape of the Earth.

Amongst them was Isaac Newton, whose theories of gravity suggested to him

that the Earth was much flatter, kind of grapefruit-shaped.

It had become the burning issue of the day.

This was the age of the Enlightenment,

an era which was fanatical about knowledge,

and knowing the shape of our planet was critical.

The row between Cassini and Newton had become so fierce that this group of men were sent out to settle it.

And that would take nothing less than a practical measurement of the curvature of the Earth.

This expedition was completely unprecedented.

It represented the very pinnacle of the Enlightenment, the new age of experimental science.

Scientists themselves called it "the greatest expedition that world had ever seen".

Fired by academic fervour, they headed off to the equator in Peru - now Ecuador.

For the three chief scientists, this was their opportunity to shine.

Bouguer might recover some of the faded glory of his youth,

while La Condamine and the ambitious Godin might make their reputations.

And, for this, they were prepared to give three years of their lives.

But, soon after setting sail, they were about to make their first big mistake.

After five weeks at sea, the group stopped off at Santo Domingo in the Caribbean.

This was the perfect place to test their instruments

and wait for the letters of permission

to be exchanged back and forth between the French diplomats and the Spanish, who ruled Peru.

They had some time on their hands -

time to enjoy the relaxed surroundings.

This French colony would have seemed to them a paradise,

filled with exotic and beautiful people.

As soon as Godin, the expedition's self-appointed leader,

set foot on land, he set his heart on a local woman, named Gousan.

As one of the crew wrote in a letter at the time...

"Love is taking up all his time.

"I hope that his wife doesn't hear of her Adonis's infidelity.

"She will perhaps take revenge.

"It is very annoying that honest people are at the mercy of a young beard without experience."

Even back in the 18th century,

Godin knew exactly who - or rather what - were a girl's best friend.

But this gift was to bring nothing but trouble.

Unfortunately, Godin hadn't used his own money to buy the diamond.

As leader of the group, he had control of the expedition coffers.

And it was this, the expedition's money, that Godin had squandered.

He'd spent a whopping 1,000 ecus, which is about ?23,000 today!

So this extravagance had just put the whole expedition under threat.

To lose so much money at this early stage was a disaster.

The remainder was barely enough to get to Peru.

Failure at this stage would mean returning home to face humiliation and the end of their careers.

The other scientists, La Condamine and Bouguer,

were furious about Godin's extravagance with their money.

Seniergue, the expedition surgeon, described the escalating tension in a letter home.

"Mr Godin has not been speaking to Mr de la Condamine and Mr Bouguer for some time now.

"They fight like cats and dogs, and attack each other's observations."

Merci.

"It is not possible that they will remain together for the rest of this trip."

What should have been a close-knit team,

gearing up for a challenging expedition,

became a bickering band of rivals.

And they hadn't even reached Peru yet.

Now they had to go right through to the heart of Peru to reach the equator.

And that whole area, particularly round the Amazon, was completely uncharted.

Few Europeans had been there.

It was a monumental task for any group.

But, for men who were not only desperately short of money

but not even speaking to each other, it seemed impossible.

Finally, on March 10th 1736, they reached Peru.

But they couldn't proceed without more money.

And so they headed to the area's capital, Quito,

hoping they might borrow funds from the Spanish authorities there.

To reach Quito, the expedition had to go inland,

across hundreds of kilometres of uncharted land,

and handle some very unfamiliar terrain.

One ticket, please. Una billet, por favor.

Hola!

People use these every day for work.

It's the normal form of transport across these whopping great gorges.

They wouldn't have seen anything like this in the comfortable boulevards of Paris.

I mean, this would have been totally unfamiliar terrain for them.

250ft-deep gorges,

huge waterfalls,

and they believed - quite rightly because they had no other knowledge -

that all this unfamiliar terrain and hidden in these trees were monsters.

Headless monsters, one-eyed cannibals, all kinds of terrible things.

Whatever creatures they imagined, real dangers lurked in these forests.

From bears and snakes to more insidious killers...

insects carrying deadly diseases.

On top of these threats, now the French scientists unwittingly made their journey even more difficult.

They hadn't been speaking to each other for ages.

And now they decided they'd just had enough, and they were just going to travel separately.

All the way to Quito. Seems a crazy thing to do.

It's certainly breaking one of the golden rules of travel.

Godin commandeered the equipment and the guides, with Bouguer following shortly behind,

leaving La Condamine to cross through one of the world's most hostile environments alone.

And I'm following in his footsteps.

La Condamine canoed up the coast, and then up here - the Esmeraldas River - so he could get inland.

And he had a real genuine interest for exploring.

And this would have been a complete treasure trove for him.

Round every bend in this river there would've been something new. He'd be bursting to understand it.

It wasn't long before his curiosity led him to the first significant discovery of the expedition.

As La Condamine made his way through the jungle, he came across a group

of local Quechua Indians, and they were collecting sap from the trees.

It was a strange pliable substance,

the like of which La Condamine had never seen before.

"When fresh, by means of moulds, it takes any shape given to it at pleasure.

"It is impervious to rain but its most remarkable property is its elasticity.

"Of it are made infrangible bottles, boots

"and hollow balls, which can be flattened at will,

"but which, when the pressure that flattens them is removed,

"assume again their pristine form."

La Condamine had chanced across rubber.

Montserrat Rios is an ethno-botanist, studying how the local Quechua people use rubber.

Arturo? Quechua Indian? Wow.

Arturo Grefar is an expert rubber tapper.

The way to collect the rubber is that you have to cut a V on the trunk.

So the rubber is right up in between the bark and the tree itself?

Yes. OK.

So the local people were doing this

when La Condamine came through?

Yes, this is a very old practice, since pre-Hispanic.

And it's the same practice now...? It's the same practice now for thousands of years. OK.

Arturo, can I have a go?

Thanks very much. OK, stand back.

That's a bit rough...

And another one?

Another one, like this.

Blimey, it looks a bit untidy. Well...

It's not as good as yours!

So Arturo, once you've collected the rubber, what do you do with it then?

He collect the rubber and then he make balls, rubber balls. Right.

So, hang on. Oh, I've got the idea. OK, it picks it up.

It kind of picks it up.

It's a long process, though. You just keep doing that?

Yes, it's a long process.

It takes flipping ages.

Arturo, what do you do with the rubber you collect?

I love it. La Condamine came through here and discovered something that revolutionised Europe in many ways.

It was a tremendous discovery for us 300 years ago.

And yet, Arturo and his people, it's completely routine.

La Condamine immediately recognised the potential of this extraordinary new material.

He sent back the first specimens of rubber seeds and wrote a meticulous paper.

That prompted the rubber boom of the Victorian era,

creating millionaires and shaping empires.

So, thanks to La Condamine sending back the rubber samples and writing his papers,

he kick-started the rubber industry as we know it today.

So we've got him to thank for rubber tyres, windscreen wipers,

inflatable rubber boats, washing-up gloves, condoms...

I wonder if they were originally called La Condamines!

Things seemed to be looking up for La Condamine.

He'd discovered rubber, and he was now on his way to Quito to join the rest of his expedition.

But the reality was a bit different.

He was lost in this rainforest.

Even worse, his two guides had just taken off.

So now he was alone...

..except for the company of jaguars,

pumas,

tarantulas

and poisonous snakes.

And this is what he was up against -

a solid wall of rainforest.

It's really hard work to get through, even with a sharp machete like my one.

La Condamine just had an axe, and he had no jungle experience whatsoever.

And neither do I.

And everything seems to be so intent on biting or poisoning

or scaring the pants off me.

He would have recognised things like bananas, thank heaven, and they were the things that kept him alive.

Everything else, just like me, seems so alien.

It gives me the willies!

I'm not joking!

After a few days, La Condamine developed a raging fever.

And it could have been any one of countless fatal diseases.

Chances were

he would die here alone.

While La Condamine was lost in the jungle...

..the rest of the expedition had safely arrived in the city of Quito.

And, with the expedition virtually penniless,

Godin tried to address the money problems that HE had created.

He met with the local Spanish governor, El Sado,

and he asked him for the money the expedition so desperately needed.

But El Sado flatly refused.

It was a blow, as the most powerful and wealthy man

in the area - Dionisio El Sado - was their only hope.

Now the French scientists were stuck.

They had no choice but to wait for La Condamine

and hope that his higher social status would help them persuade El Sado.

After eight days of terrible sickness and surviving only on bananas,

La Condamine's luck finally turned when his fever broke.

He spotted a mountain peak and decided to follow it.

"Having reached the highest point of the edge, I was seized by a sense of wonder,

"mixed with admiration, at the appearance of a large valley.

"The city of Quito, far off,

"was at the end of this beautiful view."

Unbelievably, La Condamine had survived.

With Quito in sight, he was saved.

As he entered the city, all hopes of saving the mission rested on him.

But, instead of going off to see El Sado

and making the essential request for the money on which the whole expedition depended,

La Condamine hid himself away in his rooms,

and wouldn't come out.

Everyone waited for La Condamine to announce himself.

But, day after day, nothing.

El Sado grew increasingly incensed.

Why did this foreigner not announce himself?

Was he too arrogant, too superior?

The whole mission, even their ability to get home, was hanging on a thread.

"Given that I had only taken with me my instruments, a hunting outfit and a hammock,

"I found myself incapable of appearing in public in any decent fashion when I arrived in Quito.

"And, although our companions had used 17 mules to carry cargo, as well as persons,

"it had not been possible in my absence to find a place for a single one of my trunks.

"Not even for my bed."

It was a full week before La Condamine was able to see El Sado.

In this very room La Condamine finally got to meet El Sado.

El Sado demanded to know why he hadn't been to see him before.

La Condamine answered, he couldn't possibly meet a man of such stature and importance dressed in rags.

Very cleverly, he turned a moment of gross insult into flattery.

"I completely satisfied the president on all counts.

"And since this first conversation, I am able to count on his family's friendship and trust."

Well, up to a point.

In fact, El Sado didn't give him a single penny.

He did allow La Condamine one concession -

the dubious honour of opening up a shop in Quito, where he could sell his belongings.

It was all a bit humiliating for La Condamine,

but he did manage to sell enough to get by for a few weeks.

What had seemed to La Condamine like a victory left them hardly any better off.

18 months into their expedition, 10,000 kilometres from home, and almost completely broke,

and they hadn't even made one scientific measurement yet.

It seemed as if their hopes of scientific glory were in tatters.

And things were about to get much worse.

Having exhausted all options for raising money in Quito,

they were forced to start their measurements with what meagre funds they had.

So, they headed off into the wilderness towards the equator.

Within days, Couplet, the youngest member of the team, collapsed.

The expedition surgeon, Seniergue, suspected malaria and administered

the most popular treatment of the time - bleeding and purging.

When this didn't work, the poor lad was treated to a local cure.

"A lemon stuffed with gunpowder and guinea pepper

"is insinuated into the anus, and changed two or three times a day...

"..until the patient is judged to be out of danger."

Despite - or even because of - these treatments, young Couplet died two days later.

It was a harsh reminder of the ever-present threat

of disease and death that hung over them all in this alien land.

What's more, Godin, Bouguer and La Condamine were now a man down,

with all their work still ahead of them.

The men were upset by Couplet's death, but it didn't knock 'em off track.

Partly because they were such determined men, and partly because

early death was a pretty familiar occurrence in those days.

Life had to go on.

But before the expedition could continue, they had to sort out their desperate money problems.

So La Condamine came up with a remarkable plan.

Despite his earlier problems in the rainforest, he volunteered to go across to Lima to raise some funds.

And that would be a whopping distance of 2,000 kilometres.

'Unbelievably, La Condamine was about to set off alone again.

'His determination was either foolhardy or incredibly brave.'

Looking around, I can see it's mostly fields.

It's all cultivated.

And it looks relatively gentle.

But in La Condamine's time, this was all rainforest,

and it would have been even harder to get round.

It's hard enough now.

On this second trek across country, he made another significant discovery.

He saw people harvesting a natural chemical - quinine - from the bark of cinchona trees.

And he was intrigued.

In the 18th century, malaria was still endemic in Europe.

Quinine was known as a treatment there,

but it was surrounded in mystery, because sometimes it worked and sometimes it didn't.

'Botanist Pablo Lozano took me to a cinchona tree to explain why.'

OK. Well done!

You have a red bark, and there is another two kinds of bark.

A yellow and a white one. OK.

Same cinchona tree... but different bark.

Another species of cinchona. Different species. OK.

So now, if I was to take...

a little bit of this, this would protect me from malaria, right? Yes.

It's bitter.

You're lucky, because this is the red bark.

It has the highest content of quinine.

In the 18th century, there was a confusion of the species.

Here in Peru, the locals knew that, of the three distinct species of cinchona,

only this one, with red bark, was effective against malaria.

But in Europe, they didn't know this.

So the Peruvians and merchants made a good trade, sending any old bark to unsuspecting Europeans.

So La Condamine came through and picked up that

out of the three types, one of them was better than the rest?

Yes, he spent three days talking with the local people,

and he identified the real species - the red bark.

I think that's fantastic that, in just three days, he'd discovered this fantastically important thing.

La Condamine wrote up what he'd learnt from the locals,

with meticulous drawings, and sent it back to France.

For the first time, doctors were able to use quinine reliably,

and for the next 200 years, it became the only effective treatment for malaria,

saving millions of lives.

Had La Condamine made his great discovery just a few weeks earlier,

then young Couplet might have been saved from dying of malaria.

La Condamine continued onto Lima, on his quest to get money for the impoverished expedition.

Out of the whole French team, it's La Condamine I have the most affinity to,

cos he really wanted to be an explorer.

And I think that he had a genuine love

of that feeling of adventure and new places...that I have.

But he had a real sense of adventure,

a certain flair. There was a lovely spark within him.

'La Condamine's daring paid off once again when he got to Lima.

'He secured a generous loan of 12,000 pesos -

'the equivalent of ?230,000 today.

'He returned triumphant to greet Bouguer and Godin.

'At last, they had sufficient funds, and they could begin their measurements.

'Finally, after 18 months, after illness,

'a death and the loss of their funds,

'they had reached the equator - their destination.'

I'm here at the equator.

If I jump here, I'm in the northern hemisphere.

If I jump here, this is the southern hemisphere.

The equator was their reason for travelling to Peru.

It was the very heart of their plan to measure the curvature of the Earth.

Their mission was to come here to the equator and measure the degree of latitude,

and compare that to a measurement

that was already known north up in France.

And by looking at the difference between the two,

they could determine the true shape of the Earth.

'It sounds simple on paper.'

Beautiful!

But this plan would require climbing some of the world's largest mountains.

The Andes formed a crucial part of the measurements.

The first stage of measuring a degree of latitude

was to measure a long line, hundreds of miles long, across the equator.

And in this rugged terrain, it's not the kind of thing you can do with a tape measure.

'Instead, they would calculate the length of the line mathematically,

'using the heights of the Andes for sightings.'

So the plan was to use triangulation,

which is straightforward trigonometry.

Here's the equator,

and they needed to measure a line right down the length of the Andes, hundreds of miles long.

And they would climb... three peaks

and put markers on top of them

that could be clearly seen from the other mountains.

Then they would measure these angles.

And because they knew all the angles,

they could easily calculate the distance between the mountains.

So they'd climb more mountains and measure more angles,

and continue this chain of triangles, down the whole length of the Andes.

And, that way, they could accurately measure a line hundreds of miles long.

They would then take star sightings at each end of the line

to find how many degrees of latitude this long line corresponded to.

And, from this, they could calculate the length on the ground

of a single degree of latitude, to reveal the shape of the Earth.

ARGUING IN FRENCH

While utterly committed to this scientific plan, their arguments continued.

And so, they split up - again.

Godin went his own way,

while the more diligent Bouguer and La Condamine went another.

And so these two groups set about climbing the Andes, mountain by mountain.

Their first ascent proved to be a really tough opener.

This is Pichincha, and it's a massive high volcano.

It's almost 4,800 metres high.

They had no idea of the scale of this thing.

They didn't know what they were letting themselves in for,

which I think's probably a good thing.

Maybe if they had known, they wouldn't have come.

'They struggled up towards the peak,

'where they planned to plant a marker for their first sight line.'

As they got higher, the conditions just got worse and worse.

As they got near the top...

..they just couldn't see anything - just like us now!

But still, they kept on going.

As they climbed higher,

they started to feel really odd.

They got ill,

started to get headaches, they were nauseous and generally very, very weak indeed.

"We found ourselves, at first, considerably incommoded by the rarefactions of the air.

"Particularly those among us who had delicate lungs."

What they didn't know was they were suffering from altitude sickness,

and those effects are working on me right now.

But I'm an experienced climber, so I know what to expect,

and because I'm aware of that, I could make plans.

I could put oxygen in place,

I could have an altitude acclimatisation plan, and climb slowly.

They knew none of these things, and just kept pushing on through

the very dangerous effects of altitude sickness, which we now know can kill you.

They finally made it here, to the summit,

and conditions would have been pretty much like this.

Cold and no visibility at all.

As they struggled to plant the markers at the peak, they were blighted by even worse conditions.

"We experienced extreme cold.

"There, looking at each other, our clothes, eyebrows and eyelashes covered in icicles,

"we provided each other with a singular spectacle."

After surviving 23 days, and the most appalling conditions on the summit,

they gave up, and came down here about halfway.

It wasn't such a good position,

but they could make their measurements and survive.

It had taken them about four months to get one measurement.

And they had 25 mountains left.

'But driven by their scientific obsession, turning back was unthinkable.'

Another day, another volcano.

This is Cotopaxi, the world's highest active volcano.

I've climbed this thing six times, and it's often like this.

You can wait weeks for a decent weather window to get up.

'As the conditions became more and more punishing,

'it became clear that their mission would take far longer than they'd anticipated.

'And yet, still they refused to give up.'

They spent days or even months waiting for the weather to improve

so they could continue with their measurements.

So they'd plenty of time to think.

And during that time, La Condamine came up with a great idea.

But it was the last idea you would think of on top of a mountain.

'It was an idea that would transform both science and everyday life,

'and still impacts on us today.

'It was the foundation of the metric system.

'Larrie Ferreiro, a historian of science,

'considers this one of La Condamine's most important contributions.'

There he is! How are you? All right, thank you. What a fantastic market!

It was a problem for many years.

Villages, towns, cities, countries, didn't have standard measurements

that allowed traders to go from one area to another and sell the same goods in different places.

The inch was based on the thumb.

That's my inch, from this joint to there.

OK, so mine's bigger! Yes.

We'd sell yours but buy mine! Yes.

The yard was another one. The yard was ostensibly from the nose to the end of the hand.

This is how you'd measure cloth. And this was a yard. OK.

Let's have a little comparison then. Let's line up our noses up here.

Yours is longer. Yes.

If I was buying, I would want to be doing the measuring - not you. Yeah!

What else was there? Well, the foot. Now, the foot was based on somebody's foot. Probably a king's foot.

You have larger feet. I've got big feet,

cos I'm small, but stable. OK. LAUGHTER

'La Condamine, who worked constantly with weights and measures, saw that something had to be done.'

What La Condamine had come up with was an idea that went beyond

just the borders of cities and countries, but spanned the entire globe.

Can you take a measurement based on the globe itself,

and make a standard out of it and use that across the world?

And he was the person who came up and fully developed an idea of a universal measurement.

'This revolutionary idea was the basis for the metric system.

'And, in 1793, the metre was defined

'as one ten millionth of the distance from the North Pole to the equator.

'La Condamine developed this idea over the many, many months

'that the group struggled up and down the Andes, making their measurements.'

After two years in the mountains, they had completed their triangulation -

measuring a line hundreds of kilometres long down through the Andes.

And although they'd never really pulled together as a team,

as scientists, they were second to none.

And even though they'd learnt the hard way, they'd finally become masters of the hostile environment.

With the ground measurements in place, they just had some star sights left to do.

So it seemed the end was in sight.

But with this group, nothing was easy!

'At the end of their triangulated line through the mountains was a town called Cuenca.

'And they came here to carry out their star sightings.'

And it was here that fate took a remarkable turn.

I can barely believe what happened next.

'The group were invited to a bull fight,

'which, after years in the mountains, was a welcome spot of recreation.'

I think I'm gonna... barely be able to watch it.

But back then, it was a fantastic social occasion. Everybody came.

The whole village would have turned out for this.

Godin, La Condamine and Bouguer take their seats, up here.

And, as they look down, they can hardly believe their eyes,

because here's Seniergue, the expedition's surgeon,

and on his arm he's got Manuela - a beautiful local girl -

and he makes a big fuss of bringing her in.

The crowd couldn't believe their eyes.

And they were angry, because here's a French guy with a local girl,

who they knew was previously engaged to a local guy.

So, not only were they angry at Seniergue, but the whole French expedition.

Immediately, Seniergue just plays to the crowd.

And these three up here can just feel the crowd getting angry.

Because Seniergue had flaunted this relationship, it just enraged the crowd.

And the crowd turned into an angry mob.

They surged forward around Seniergue, and began to stone him.

And our three guys - La Condamine, Bouguer and Godin -

they almost responded, they almost went to help him, just like a proper team.

But they didn't. They saved their own skins instead.

But as they fled the bull ring, the crowd followed them.

Soon, the mob were hard on their heels, brandishing knives and swords.

Now, on the brink of completing their mission, they were in fear for their lives.

CRIES OF PAIN

'As Bouguer lay bleeding, it looked as if the expedition was over.'

Luckily, Bouguer's wound wasn't fatal,

but Seniergue had been stoned and stabbed many times.

And he endured a long and painful death, lasting four days.

'It was now October 1739, and the scientists had been away from France for over four years.

'But despite the hostile atmosphere in Cuenca, the team still refused to abandon their scientific quest,

'and they remained here to take their star sightings.

'Larrie Ferreiro took me to the very church where they did this final stage of their measurements.'

So why would they have come here to this church?

They used it as an observatory for some of their sightings.

If I was gonna make star sightings, I'd be outside using me sextant.

The sextant is what we would use today, but it really wasn't perfected at that time.

Instead, they used an instrument known as a zenith sector,

which resembled this drain pipe that I happen to have here.

OK, how does it work? Let me show you how it works.

Have a lie down. All right.

OK. Tell me what you see. Well, a small patch of ceiling,

but I presume they would be seeing a small patch of the sky.

And that's exactly what they'd be looking for - a small patch of sky vertically above them.

They would wait for a particular star to cross through that patch

and determine when it was right above them. That way, they could discover their latitude.

Now, the next step was probably the hardest.

They had to do this at each end of the base line.

Bouguer went north and La Condamine stayed here in the south.

Each one had to make the same set of observations on the same star

on the same night to get the arc of latitude they required.

'This would tell them how many degrees of latitude

'their line down through the Andes corresponded to.'

'And from that, they could calculate the length of a single degree of latitude.'

How long did all these measurements take?

Well, each set of observations could take weeks or even months to make.

Ultimately, it took them years - three years, in fact.

So it took them three years to do what I could do

or we could do right now with my GPS in a few days?

That's right. Or even a few seconds.

But after these three long years, the sightings were complete.

The trip, which was supposed to take three years, had now taken eight,

and cost the lives of two men.

They had endured stifling rainforests and freezing conditions,

incessant arguing and murder attempts.

All in the pursuit of science.

All to find just one number.

Finally, they had a result.

It was just one number, but it was an incredibly important number.

110.61 kilometres, which was the length of one degree of latitude at the equator.

And crucially, compared to one degree of latitude in France,

it was shorter, which meant that the Earth was kind of grapefruit-shaped -

fat in the middle and flatter on the poles -

which was exactly as Sir Isaac Newton had predicted.

All that hard work and tenacity and attention to detail

from Godin, La Condamine and Bouguer had paid off.

The result was a revelation that would change navigation and map-making forever.

But perhaps their greatest legacy was from the chance discoveries they made along the way.

They kick-started the rubber industry,

giving us many things we take for granted today, like water-proofing and car tyres.

They gave us quinine, a chemical that has saved millions of people from malaria.

And they gave us the basis of the standardised metric system.

What is a metre? What does a kilo of apples weigh?

What's more, they provided support for the theories of Isaac Newton,

whose work would change the course of science entirely.

But most of all, this seemingly shambolic group of men

had revealed one of the most fundamental of all things -

the true shape of our planet.

'Yet, for the French team, there were no celebrations.

'At the end of their epic mission, there was only enough money left to send one of them home.'

Bonne chance. A Paris! Oui.

'Bouguer jumped at the chance to return to a hero's welcome.'

Bonne chance. Au revoir.

'La Condamine headed into the Amazon in search of more adventures.

'While Godin, bitter and isolated, never returned to Europe.'

It was a modest and subdued end

for these most unlikely heroes of science.

Subtitles by Red Bee Media Ltd - 2006

E-mail: [email protected]

Utopia - the better place.

Somewhere between fiction and reality.

The idea has exerted

such a hold over us, but why?

Join me, Richard Clay,

as I venture across hundreds of years of art,

literature and philosophy.