Original subtitles

Electricity is one of nature's greatest forces.

we'd harnessed it to light and power our modern world.

Hundreds of years of scientific discoveries

and inventions brought us here.

But it would take the eccentric genius of one man

to unlock the full potential of electrical power.

In the winter of 1943,

Nikola Tesla looked out

across the Manhattan skyline

for the very last time.

Tesla had been born into a world powered by steam and lit by gas.

But before his eyes, he saw a new world.

A world transformed,

a world powered by electricity.

His world.

Frail, lonely

and still mourning the death of one of his beloved pigeons,

this extraordinary and eccentric genius

knew that his life's work was done and he laid back on his bed to die.

It would be three days before anyone found his body.

Just over 200 years ago, early scientists

discovered electricity could be much more than simply a static charge.

It could be made to flow in a continuous current.

But they were about to discover something profound.

That electricity is connected to magnetism.

Harnessing the link between magnetism and electricity

would completely transform the world

and allow us to generate seemingly limitless

amounts of electrical power.

This is the story of how scientists and engineers

unlocked the nature of electricity

and then used it in an extraordinary century of innovation and invention.

But not before one of the most shocking

engineering rivalries in history was finally laid to rest.

Our story begins in London,

at the beginning of the 19th century,

with a young man who would further our understanding of electricity

as much as any other.

On 29th of February, 1812,

a 20-year-old self-educated bookbinder called Michael Faraday

came here to the Royal institution of Great Britain.

He was surrounded by the great and the good of the academic world.

And he was about to listen

to one of the greatest scientific minds of the age.

Faraday, the son of a blacksmith, had finished his formal education

when he was just 12 years old.

He would never get to university.

But he wasn't finished with learning,

as he was fascinated by science.

Faraday worked long and hard during the day, binding books.

But in the evenings, he'd read whatever scientific literature

he could lay his hands on.

He loved learning new things about the world

and he had this constant desire, this passion,

to understand why things were they way they were.

Reading scientific papers was one thing.

But to really satisfy his craving for knowledge,

Faraday was desperate to see the experiments themselves.

And he eventually got his chance

when he was given a ticket to attend one of the last lectures

of England's greatest chemist of the time, Sir Humphry Davy.

It was to change young Faraday's life forever.

After watching Davy, awe inspired and full of ideas,

Faraday knew what he wanted to do with his life.

He was determined to dedicate himself to furthering science.

And that's just what he did.

Within a year, Davy had appointed him

as an assistant at the Royal institution.

With Davy as his patron and, well, his boss,

Faraday studied all manner of chemistry.

But what would inspire his greatest breakthroughs...

were the invisible forces of electricity and magnetism.

In 1820, both were being studied by a Danish scientist,

Hans Christian Oersted,

who'd made an extraordinary discovery.

He passed an electric current through a copper rod

and brought it close to a magnetic compass needle

and saw that it made the needle rotate.

To Oersted, it was remarkable.

He'd shown, for the first time,

an electric current can create a magnetic force.

He'd bound electricity and magnetism together.

Today we call it electro-magnetism.

And it's one of the fundamental forces of nature.

Oersted's discovery sparks off a whole new

aspect of inventive activity

around and about the fields of electricity.

You can almost see electrical experimenters vying,

competing with each other,

to find new links between electricity and the other powers of nature.

At the Royal institution,

Faraday set about recreating Oersted's work,

which would mark his first steps to fame and fortune.

And through his rigorous research,

he concluded that there must be a flow of forces

acting between the wire and the compass needle.

The device he designed to demonstrate it

would change the course of history.

Faraday created a circuit using a battery like this,

a pair of wires and a mercury bath.

Now, the circuit carries on through these copper posts,

and this wire hangs freely, it dangles into the mercury.

Now, because mercury is such a good conductor,

it completes the circuit.

When the current runs through the circuit...

..it generates a circular magnetic force-field around the wire.

Now, this interacts with the magnetism from a permanent magnet

that Faraday had placed in the middle of the mercury.

Together they forced the wire to move.

Faraday had proved that this invisible force really does exist

and he could see its effect - circular motion.

This beautiful device was the first to convert electric current

into continuous motion.

Basically, it's the earliest ever electric motor.

But Faraday was about to take this experiment further.

One of the lasting effects

of Faraday's discovery of electromagnetic rotations in 1821,

was that it showed that there was a relationship of some sort

between electricity and magnetism and motion.

Faraday explored this relationship in detail

and set himself an even more difficult challenge.

To use magnetism and motion to make electricity.

Eventually, his obsession,

hard work and determination paid off.

The breakthrough came

on the 17th of October 1831,

when Faraday took a magnet like this and moved it

in and out of a coil of wire.

He was able to detect a tiny electric current in the coil,

moving one way...

..and then the other.

Faraday knew he was onto something.

A few days later,

instead of moving the magnet through the conducting wire coil,

he set up the equivalent experiment

by moving a conducting copper plate through the magnetic field.

He didn't know it at the time,

but as his spinning disk cut through this magnetic field,

billions of negatively charged electrons

were deflected from their original circular course,

and began to drift towards the edge.

A negative charge built up at the outer edge of the disk,

leaving a positive charge at the centre,

and once the disk was connected to wires,

the electrons flowed in a steady stream.

Faraday had generated a continuous flow of electric current.

Unlike a battery,

his current flowed for as long as his copper disk was spun.

He'd created electrical power directly from mechanical power.

Although Faraday's discovery of conduction was extraordinarily important in its own right,

and had profound effects for the understanding of electricity

and technology for the rest of the 19th century,

for Faraday what it did is open up a decade of powerful research,

because it gave him a clue about how he should pursue his research.

While Faraday continued his work,

trying to understand the very nature of electricity,

inventors across Europe were less interested in the science

and more interested in how electricity could make them money.

What's actually quite remarkable, certainly from a contemporary perspective,

is that, by and large,

nobody really seems to care very much what electricity is.

You don't have great theoretical debates

as to whether it's a force, or a fluid, or a principal, or a power.

What they're really interested in is what electricity can do.

Faraday, living in a world of steam power,

was informing the scientific community

about the nature of electricity,

but at the same time another breakthrough

in how we could actually use it had been made.

This would be the first device

that really brought electricity out of the laboratory

and into the hands of ordinary people.

The telegraph.

The key to understanding the telegraph

is understanding a special kind of magnet, an electromagnet.

Basically, a magnet created by an electric current.

The first electromagnets were developed independently

by William Sturgeon in Britain and Joseph Henry in America.

And just as Faraday had discovered that by coiling his wire,

he could increase the current in it produced by the moving magnet,

so Henry and Sturgeon discovered

that by adding more coils in their current carrying wires,

they could make a more concentrated magnetic field.

Basically, the more coils, the more turns, the stronger the magnet.

So if I pass a current through this electromagnet,

you can actually see the effects of the magnetic field.

This is the standard school experiment

of sprinkling iron filings on top of the magnet.

If I give it a tap,

see the iron filings follow the contours of the field.

This allows us to visualise the effects of magnetism.

To make an electromagnet even stronger,

Henry and Sturgeon discovered that they could place

certain kinds of metal inside the electromagnetic coil.

The reason iron is so effective is fascinating

because you can think of it as being made up of lots of tiny magnets,

all pointing in random directions.

At the moment, this is not a magnet.

The tiny magnets inside are aligned similarly to these compass needles.

If you see, they're all pointing in different directions.

But when you apply a magnetic field, they all align together,

they all combine, these magnets,

and cumulatively they add to the strength of the electromagnet.

So what Henry and Sturgeon did,

was place two electromagnetic coils on each arm of their horseshoe,

to create something that was many, many times more powerful.

And we can see the power of this horseshoe electromagnet.

If I turn it on and use something slightly bigger than iron filings,

these small pieces of iron,

look at the strength of the magnetic field, holding them in place.

What's important to remember, of course,

is that this electromagnet only works

all the time there's a current passing through it.

As soon as I turn off the current...

the magnetism disappears.

Early experimenters showed off this power by lifting metal weights.

Henry even made one big enough to lift a tonne-and-a-half of metal.

Impressive but not world-changing.

But place that magnet much further away, at the end of a wire,

and suddenly you can make something happen at your command.

In an instant.

This ability to control a magnet at a distance,

is one of the most useful things we've ever discovered.

If electricity can be made visible

a long way away from the original source of power,

then you've got a source of instantaneous communication.

By the middle of the 1840s,

Samuel Morse had developed a messaging system,

based on how long an electrical circuit was switched on or off.

A long pulse of current for a dash, a short burst for a dot.

This allowed messages to be sent and received by using a simple code.

Contemporary early Victorian commentators

reflect on the fact that electricity

and the telegraph is literally making their world a smaller place.

You very often get a sort of rhetoric throughout the 19th century,

when people are talking about the telegraph,

about how more communication, more understanding,

will render war obsolete,

because we'll all understand each other better.

I mean, retrospectively, it seems...hopelessly utopian.

By the 1850s,

Europe and America were criss-crossed

with land-based telegraph wires,

but the dream of instant global communication

was frustratingly out of reach.

This was because there was still no cable

capable of carrying messages

between two of the greatest powers on earth -

Britain and America.

Many experts were convinced

that a working Atlantic cable was impossible.

But those who disagreed knew that if they could solve this problem,

it could make them serious money.

And in the 1850s, American businessmen and British engineers

joined forces to prove this could be done.

Attempt after attempt ended in disaster.

The heavy cables kept snapping in heavy seas and storms.

Finally, on 29th July 1858,

two parts of a cable were spliced together in mid-Atlantic.

You see, a single cable was simply too big to be carried by one ship.

Then one end was taken to Newfoundland,

and the other end to south-west Ireland.

Six days later, the first direct link

between the two most powerful nations in the world was in place.

The project was hailed a huge success

and a formal message of congratulations

was sent from Queen Victoria to President Buchanan.

But before the celebrations were over,

things started to go very wrong.

This is Chief Engineer Bright's original notebook.

You can see here Queen Victoria's original message.

Now, it's only 98 words long, but it took 16 hours to transmit.

The telegraph operators on the other side found it very hard

to decipher the message.

The electrical signals they were receiving

were blurred and distorted

and they kept asking for words to be repeated over and over again.

So you can see here,

"Repeat after sending. Waiting to receive, no signals."

Clearly, transmitting across the Atlantic

wasn't going to be as straightforward as people had hoped.

Over the next few days, several hundred messages were exchanged,

but those arriving in Newfoundland

became almost impossible to decipher,

just a jumbled mess of dots and dashes.

There was a serious problem with the cable and it was getting worse.

Well, the 1858 cable was never fully repaired,

and the end finally came when British engineer Wildman Whitehouse

mistakenly believed that by increasing the signal voltage

he could force the messages through to Newfoundland.

The cable simply stopped working altogether.

At the time, increasing the voltage

by using more powerful batteries made sense.

Most experts believed electric current

flowed through a cable, like a fluid in a pipe.

Increasing the voltage was the equivalent

of increasing the pressure in the system -

forcing the current through to the other end.

But the telegraph was actually carrying pulses,

or ripples of currents along the cable,

not a continuous stream.

And over long distances,

these pulses were becoming distorted,

making it difficult to tell what was a short dot

and which was a longer dash.

By studying the effectiveness of underwater cabling,

scientists were beginning to understand

that electric current didn't always flow like water,

but was also creating invisible electromagnetic waves, or ripples.

And it's this breakthrough that would lead to a new branch

of research into the electromagnetic spectrum,

and solve the problems of the Atlantic telegraph.

In effect, the Transatlantic Cable

was a giant, ambitious, hugely expensive experiment.

The failure of science to keep pace with technology had been exposed.

And a new, more theoretical and, for me, much more exciting approach

to understanding electricity began to unfold.

Armed with this new understanding of how electric pulses

actually moved along the cable, improvements were made

to its composition, design, and how it was laid.

It would take another eight years of scientists and engineers

working together before a working cable was finally put in place.

And on Friday 27th July 1866,

a message was sent from Ireland to Newfoundland.

Clear and crisp.

"A treaty of peace has been signed between Austria and Prussia."

At last, the dream of instant transatlantic communication

had become a reality.

The success of the 1866 cable makes the world a smaller place.

Yet again.

The change from a world where it took days or weeks or months

for information to travel,

to a world in which information took seconds or minutes to travel -

it is far more profound

than almost anything that's taken place during my lifetime.

The invention of the telegraph changed ordinary people's lives.

But it would be the breakthroughs

in how we used continuously flowing electric current

that would have an even greater impact.

Because inventors were developing a new way of using electricity.

To make something every person in the world would want -

electric light.

Until the 19th century,

we only knew of one way to make our own light - burn things.

And by the middle of the 19th century,

we'd perfected a very effective way of lighting our homes -

using gas.

A typical British home in the 1860s would have been lit like this -

highly-flammable gas

would have been pumped directly into people's houses

through a network of pipes.

But these gas lamps were too dull for large outdoor areas.

So railway stations and streets began to be lit

from a more powerful source - electric arc lights.

The first arc lights were demonstrated

by Michael Faraday's mentor, Sir Humphry Davy,

at the Royal institution as early as 1808,

and they worked by passing a continuous spark of electricity

across two carbon rods.

But their intense white glow was just too bright for people's homes.

For an electric light to compete with gas,

it would need to be subdivided into many smaller,

less powerful and more gentle lamps.

Whoever succeeded in bringing electric light

to every home in the land was guaranteed fame and fortune.

And by the early 1880s, the most famous, most prodigious,

most fiercely competitive inventor in the world

had taken on the challenge.

The American, Thomas Alva Edison.

For Edison, invention was a passion,

it's what he loved doing. He loved being in the laboratory.

The first thing that drove that passion is that

it was a lot of fun for Edison. That was the thing that he found

most exciting, is that this was something he did well,

and it allowed all of his creativity to come to the fore.

Edison is Mr Electrical Invention.

He's the man they trust.

He's the man that they think can do anything.

He's also the man who has his carefully cultivated connections

with entrepreneurs, with people that are willing to put their cash

where Edison's mouth is, so to speak,

and back him in this sort of venture.

For Edison, the money was probably the least important reason.

For Edison, the money was important for one reason -

to allow him to do the next project.

Edison had assembled a group of young and talented engineers

at a cutting-edge laboratory in New Jersey,

26 miles from Manhattan.

Menlo Park would become

the world's first research and development facility,

allowing Edison's team to invent on an industrial scale.

They worked incredible hours, you know,

one of them talked about how he hardly ever saw his children

cos he was in the lab all the time.

But they knew they were in the midst of something really important.

That if Edison succeeded,

if they succeeded with Edison, their futures were secure.

Edison's dream was to bring electric light to every home in the land,

and with his team of engineers behind him,

and the vision of an electric future ahead, he launched his campaign.

The race to bring electric light to the world was to play out

in the great cities of the time - New York, Paris, London.

Edison's Menlo Park team set about developing

a totally different form of electric lamp -

the incandescent light bulb.

In fact, Edison's light bulb design wasn't all that new. Or unique.

French, Russian, Belgian and British inventors

had been perfecting similar bulbs for over 40 years.

And one of them, an Englishman, Joseph Swan,

had been developing his own version of an incandescent lamp.

Both Swan and Edison's light bulbs

worked by passing an electric current through a filament.

Now, a filament is a material in which the electric current

flows through with more difficulty than it does

through the copper wire in the rest of the circuit.

And it relies on the idea of resistance.

Inside this jar, I have a filament made out of ordinary pencil lead,

and we can see what happens as I pass a current through it.

Down at the atomic scale,

the atoms in the filament impede the flow of electricity.

So it takes more energy to force it through,

and this energy is deposited in the filament as heat.

Now, as it heats up, its resistance goes up,

which again raises its temperature, until it glows white-hot.

Now, one of the first materials

Edison used for his filaments was platinum.

With its relatively high melting point,

platinum could be heated

to a white-hot temperature without melting.

It could also be stretched into thin strands, and the thinner the strand,

the more resistance it offered to the current passing through it.

But platinum was expensive and didn't offer enough resistance.

The race was on to find a better alternative

and the solution came when the Menlo Park team

switched to a method Swan was also developing,

using a vacuum to stop cheaper carbon filaments

from burning up too quickly.

Edison and Swan tested all kinds of different materials

for their filaments -

everything from raw silk and parchment to cork.

Edison even tested his engineers' beard hair.

Eventually, he settled on bamboo fibre,

while Swan used a treated cotton thread.

Edison and Swan's light bulb designs were very similar.

Eventually they came to an agreement and went into partnership

to sell light bulbs in the UK.

Today, many people still believe that Edison alone

invented the light bulb, whilst Swan has become a footnote in history.

But his incandescent bulb was only part of Edison's strategy.

He'd also invented an entire electrical system of sockets,

cables, and meters to go with it.

And, being a brilliant businessman,

he'd developed a ground-breaking new way of distributing electricity.

Edison knew that the key to making money from his system

was to generate the electricity in a central station,

and then sell it to as many customers as possible.

It seems obvious to us now, but until then,

anyone who wanted to use electricity

had to have their own noisy generator to make it.

Edison's ambition was huge -

he wanted to light the fastest-growing

and most exciting city in the world.

New York.

In the summer of 1882, Edison stood in a unique position,

at the centre of 19th century science and invention.

He'd patented a cutting-edge incandescent light bulb,

he'd amassed an unprecedented knowledge of electrical engineering.

And above all,

he'd cultivated a reputation among the American public

of being such a genius inventor,

that journalists hung on his every word,

and the financial muscle of Wall Street

was quick to throw itself behind his new ideas.

His vision, to electrify Manhattan,

and then, of course, the rest of the world,

was seemingly within his grasp.

Because Edison and his team

were about to launch their most expensive and risky project yet -

America's first power station,

generating continuous direct current.

Just before 3pm on the 4th September 1882, Thomas Edison,

surrounded by a gaggle of bankers, dignitaries and reporters,

entered JP Morgan's building, right behind me,

flicked one of the Edison-patented switches,

and 100 of his incandescent bulbs began to glow.

Turning to a nearby journalist, he said,

"I have accomplished all that I've promised."

Half a mile away on Pearl Street, Edison's new power station,

costing half a million dollars and four years of hard work,

had sprung into life.

The current surged through buried cables,

stretching out in each direction.

Of course it might seem obvious to us now,

but in New York back in the early 1880s,

the idea of burying electric cables underground

seemed like an unnecessary expense.

This street would have been criss-crossed

with hundreds of cables, used for telegraphs,

telephones and arc street lighting.

Looking up, you'd have seen a tangled mass of black spaghetti

blocking out the light.

Edison knew this dangerous situation had to change,

and for him to make as much money as he could,

electricity needed rebranding. It had to be considered safe.

So Edison is arguing both for the greater safety

of his DC low voltage system, and for underground lines.

He can argue that he has a much safer system

than electric arc light for streets,

or gas lighting for indoor lighting.

He doesn't have to worry about fires, or electrocution,

that all of this is much safer

because of the system he's created with this underground system.

Burying every cable was not only very expensive

but was a logistical nightmare,

because this was one of the busiest square miles in the world.

Edison chose this area for a reason.

Wall Street.

Rich, important, influential.

Because for Edison's system to make money,

all these wealthy customers

had to be within a mile of his power station.

And this was because Edison calculated

the thickest cable he could afford

would only carry an adequate amount of his continuous direct current

to customers within this range.

This was a huge leap forward

because, for the first time,

dozens of customers could be supplied by just one power station.

But there was a big problem.

Edison's network could never be economical in lighting

America's new suburbs.

They just didn't have the concentration of customers

needed to make building these expensive power stations worthwhile.

Had we stuck with Edison's way

of generating and distributing electricity,

the world would be a very different place.

We'd have to have power stations scattered around

no more than a mile apart, even in the centres of our towns and cities.

And it would be extraordinarily expensive to even provide power

for smaller communities.

But someone who held the answers to these problems

was about to enter the story.

Someone who would help create the modern world

and who'd play an integral part in one of the biggest fall-outs

in scientific history.

His name was Nikola Tesla

and he was right under Edison's nose.

Nikola Tesla was a Serbian inventor

who was born in Croatia

and who worked for Edison briefly

after arriving in New York at the age of 28.

European, introverted, a deep thinker,

he was everything Edison wasn't.

Edison and Tesla could not be more different

in the way they handled their self, appearance, and their manners,

and the way that they constructed a public image for themselves.

Edison couldn't care less about the clothes he had on

and if he spilt chemicals on his good Sunday suit,

then he spilt chemicals on his good Sunday suit.

He was, you know, basically, a very kind of slovenly guy.

Tesla, on the other hand,

even as a young man in his mid 20s, is thinking about his appearance,

how he comes across to people.

So he cares about his clothes, his manner.

Indeed, he even cares about how his photograph,

his portraits are taken,

and he always wants to make sure he has a nice, three-quarter profile

so you don't see the fact that he has a bit of a pointy chin.

The life and death of Nikola Tesla

is one of the most fascinating yet tragic stories

of scientific brilliance, cut-throat business,

and shocking public relations stunts.

The American public may have been wowed

by Edison's new direct current power stations,

but Tesla was less impressed.

He had a dream electricity could be transmitted across entire cities.

Or even nations.

And he believed he knew how it could be done -

by using a different type of electric current.

Electrical experts knew that the smaller the current

sent down a cable, the smaller the losses in it through resistance.

And so the longer the cable could be.

Tesla proposed using a method of transmitting electricity

where the currents could be lowered without a fall

in the amount of electrical power at the other end.

It was called alternating current.

Alternating current is exactly that.

It's an electric current that alternates

between moving in one direction,

then the opposite direction, very quickly.

As opposed to a direct current, which moves only in one direction.

Tesla was interested in alternating current because,

like other electrical engineers in the late 1880s,

he realised that as you raise the voltage of any current

that you transmit from point A to point B,

it's going to be more efficient to have a higher voltage.

And since the amount of electric power in a cable is its voltage

multiplied by its current, increasing the voltage,

meant the current in the cables could be reduced,

and so losses due to resistance would be less.

However, you don't want very high voltages

on the order of, say, 20,000 volts coming into your home.

So you need to step down the current

that is being transmitted over distance into your home.

And to do that, you need a converter or transformer.

Alternating current allows you to use a transformer

to make that switch from the high transmission voltage

to the lower voltage you're going to use at consumption.

Perfecting the technology to transmit electricity

hundreds of miles from where it was generated

would mark a huge step towards the modern world.

And a wealthy industrial entrepreneur

was already developing the solution.

His name was George Westinghouse.

Westinghouse believed alternating currents was the future,

but it had a big drawback.

While it was fine for electric light,

unlike direct current,

there was no practical motor that could run on it.

And no-one believed there ever would be.

Apart from Nikola Tesla.

Tesla, as an inventor, liked to say

that the first thing you need to do is not to build something,

but to imagine it, to think it through, to plan it.

And he had what modern-day psychologists would call

an eidetic memory. He could basically

remember everything that he saw

and then visualise it in three dimensions.

And they often say people that have this skill

see it about an arm's length away,

out here, and they see it in three dimensions in that space.

And all the indications are that Tesla had that ability.

This is a Tesla egg.

It's a replica of the one Tesla used

to demonstrate his greatest breakthrough

and one of the most important inventions of all time.

It showed how rotary movement

can be produced directly from an alternating current.

Crucially, one that could be generated thousands of miles away.

This was something that had never been done before.

When Tesla was working on the alternating current motor,

he was thinking big.

He was not just tinkering with one component

of the motor and saying, "Gee, if I can make that a little bit better,

"it will work out." He's actually thinking about

an entire system that involves the generator,

the wires to the motor

and the motor itself. He's a complete maverick,

thinking outside the box,

doing things very differently to his fellow inventors.

Tesla's solution was ingenious.

He fed more than one alternating current into his motor

and timed them so that they followed in sequence with each other.

The first alternating current

energised a coil of wire inside the motor,

creating an electromagnetic field

which attracted the motor's central moving part to it

and then faded.

The second overlapping current fed the next coil,

dragging the moving part around further, before it faded.

And the same for the third coil and the fourth.

The result was a revolving magnetic field,

strong enough to make the motor,

or in this case his egg, spin.

Tesla designed an entire electrical system around this

called polyphase transmission.

This meant a noisy and smelly power station,

generating lots of useful alternating current,

could now be situated away from populated areas.

And for the first time you can build large power stations

wherever you want. On the edge of town,

or a waterfall like Niagara,

and distribute the power over long distances,

and serve all the people

in a major city or metropolitan centre.

Tesla's breakthrough was the last piece of the jigsaw,

but he still had to convince the world

that his solution was better

than the direct current method championed by Edison.

Edison continued to roll out his direct current system,

building power stations across New York state.

But then Tesla met George Westinghouse -

the man who could make his dreams into a reality.

In July 1888, Westinghouse made an offer for Tesla's patents,

which has become part of the mystery and folklore

surrounding the whole Nikola Tesla story,

where it's difficult to separate fact from fiction.

Tesla was paid 75,000 for his alternating current patents

and offered 2.50

for every horse power his motors would generate.

This should have guaranteed him vast wealth

for the rest of his life but that isn't what happened.

It's clear to us now that at the time,

the AC system was a much better method

of transmitting electric power.

And you'd think that with Tesla's breakthroughs,

nothing could stand in the way of the success of AC over DC.

But one man still believed totally

in his direct current inventions,

From the filaments of the bulbs to the switches,

sockets and generators,

and he wasn't about to waste millions of dollars

on changing them.

Edison.

The battle lines were drawn.

Westinghouse and Tesla went toe-to-toe with Edison

for New York's lucrative lighting contracts.

Two completely different systems

battling it out for one ultimate prize -

the chance to light up America and then the world.

It would become known as the War of the Currents.

Both camps tried to undercut each other on cost,

but Edison believed his beloved direct current

was better than alternating current because it was safer.

Touching an Edison cable, with its low voltage,

was painful but relatively harmless.

Whereas alternating current cables

carried a much higher voltage

and touching them could be deadly.

So, what Edison was trying to do

was to again define his DC system as the safe system.

It's better than electric street arc lights,

it's better than gas,

and it's now better than high voltage AC incandescent lighting.

Right? It's the system that's safe.

You adopt the Edison system, you can be sure it's safe.

Edison claimed that AC

was a more dangerous type of current than DC

and he highlighted every accident to Westinghouse's workmen

and every fire caused by short circuits.

It was a potent message because in the 1880s,

many people were still terrified by electricity.

It could shock and even kill in an instant

and the reasons why still weren't fully understood.

For many, the idea of piping this invisible killer into their homes

was utterly ludicrous.

So the weapon used in the War of the Currents was fear.

And a little-known electrical engineer,

Harold P. Brown,

was about to take the fight against AC

to a whole new level.

It was to prove one of the most extreme

and negative publicity campaigns in history.

Brown had devised a unique and theatrical way

of demonstrating the deadly power of AC...

..and he was eager to share it with the world.

So, on a warm summer's evening, in July 1888,

he gathered together 75 of the country's

top electrical engineers and reporters

to witness a spectacle they would never forget.

Brown's plan was extremely macabre.

He'd paid a team of street urchins

to collect together stray dogs roaming Manhattan.

Out on stage, he addressed his audience.

"I have asked you here, gentlemen,

"to witness the experimental application of electricity

"to a number of brutes."

His demonstration involved electrocuting the dogs...

with DC and AC power,

in an attempt to show that AC current killed them more quickly.

And it wasn't just dogs.

Brown went on to make public spectacles of killing a calf

and even a horse.

And he moved from dogs to larger animals for a reason.

He wanted to show that the AC form of electricity was so dangerous

it could kill any large mammal, including humans.

Brown's animal experiments had persuaded American politicians

the most humane method of executing condemned criminals

should be with alternating current,

generated by Westinghouse machines.

Edison's lawyers even suggested a new term

to describe being electrocuted in this way...

..to be Westinghoused.

And at precisely 6:32,

on the morning of 6th August 1890,

a 45-year-old man, William Kemmler,

was strapped to a wooden chair

and two soaking wet electrodes

were carefully attached to him.

And as 26 officials and doctors looked on from an adjoining room,

Kemmler said goodbye to the prison chaplain and waited.

The execution of William Kemmler

marked the lowest point in the War of the Currents,

but it wouldn't quite mark the end.

Because Nikola Tesla was about to do something

that had never been seen before.

Something so wondrous and daring

that it would live on for ever in the memories of those who saw it.

Tesla had been developing a method

of generating very high frequency alternating currents

and on May 21st 1891,

at a meeting of top electrical engineers,

he demonstrated it.

In an almost magical display of awesome power and wonder,

and without wearing any safety chain mail or mask,

tens of thousands of volts, produced by a Tesla coil,

passed across his body and through the end of a lamp he was holding.

Tesla's alternating current was at such a high frequency,

that it passed through his body

without causing serious harm or even pain.

His demonstrations showed that if handled correctly,

alternating current at extremely high voltages could be safe.

The War of the Currents had been won,

by Westinghouse and Tesla.

In 1896, the new power station was completed at Niagara Falls,

using Westinghouse AC generators

to produce Tesla's polyphase current.

Finally, huge amounts of power

could be transmitted from the Falls,

to nearby Buffalo and then, a few years later,

the Niagara plant was providing power to New York City itself.

And today, almost all of the electricity generated in the world

is done so using Tesla's system.

But Tesla's story doesn't end in fame and fortune.

Although he went on to make significant contributions

to many other areas of science and invention,

to save George Westinghouse from ruin, after a stock market crash,

he gave up his claim to the royalties

from his polyphase inventions.

Nikola Tesla was a uniquely talented man and we owe him so much.

But he was also hugely complicated,

and sadly, later in life, he became more and more troubled.

He was fixated with the number three,

counting it out loud while he walked,

and he developed strange phobias with germs

and with women wearing pearl jewellery.

In many ways, his brilliant mind simply spun out of control.

As Tesla's life unravelled,

he withdrew from people

and found emotional comfort elsewhere.

He became obsessed with pigeons

and was regularly seen feeding them here in Bryant Park,

in the centre of Manhattan.

He even fell in love with one particularly unusual white bird

and when it died,

he was left heart broken.

As an old man, Tesla was left almost bankrupt and alone,

living as a semi-recluse in this hotel.

His last years were spent here in room 3327 of the New York Hotel,

sad, confused, destitute.

Edison went on to become an American hero

and his company would form part of General Electric,

even today one of the world's biggest multinational corporations.

In January 1943, the story of Nikola Tesla was coming to an end.

But looking out across the Manhattan skyline for the very last time,

he saw a sky lit up with twinkling lights,

and a million lives transformed by his genius.

The ability to generate and transmit electricity,

and the invention of machines to use it,

have changed our world in ways we couldn't possibly have imagined.

We can now generate billions of watts of electricity

every second, every hour, every day.

And whether we do it using coal, gas,

or nuclear fission,

power stations all rely

on the principles discovered and developed by Michael Faraday,

Nikola Tesla,

and all the other early electrical engineers

from an amazing age of invention.

We now take electricity for granted

and have forgotten how magical and mysterious a force it once was.

But there's something we should never forget.

Today, without it, the modern world would collapse around us

and our lives would be very, very different.

In the next episode, we tell of the electrical revelations

that led to a revolution in our understanding

of this amazing force.

To find out more about the story of electricity,

and to put your power knowledge to the test,

try the Open University's interactive energy game.

Go to:

And follow links to the Open University.

Subtitles by Red Bee Media Ltd 2011

E-mail subtitling@bbc.co.uk