Voyages of Discovery (2006): Season 1, Episode 4 - The Figure of Earth - full transcript

300 years ago, a group
of men found themselves

thousands of miles from
home, fighting for their lives.

They had traveled
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 kilometers
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 traveled
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 fervor, 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 kilometers
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 molds, 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 revolutionized
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 recognized 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 tires, 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 recognized
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 honor 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

kilometers 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 meager 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 kilometers.

'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 learned 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 traveling 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 meters 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
acclimatization 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 meter 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
kilometers 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
learned 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 kilometers, 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 tires.

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

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

What is a meter?
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.