At the dawn of the 19th century,
in a cellar in Mayfair,
the most famous scientist of the time, Humphry Davy,
built an extraordinary piece of electrical equipment.
Four metres wide, twice as long
and containing stinking stacks of acid and metal,
it had been created to pump out more electricity
than had ever been possible before.
It was in fact the biggest battery
the world had ever seen.
With it, Davy was about to propel us
into a new age.
That moment would take place at a lecture at the Royal Institution,
in front of hundreds of London's great and good.
Filled with anticipation, they packed the seats,
hoping to witness a new and exciting electrical wonder.
But what they would see that night would be something truly unique.
Something they would remember for the rest of their lives.
Using just two simple carbon rods,
Humphry Davy was about to unleash the true potential of electricity.
Electricity is one of nature's most awesome phenomena,
and the most powerful manifestation of it we ever see
is lightning.
This is the story of how we first dreamed of controlling
this primal force of nature,
and how we would ultimately become its master.
It's a 300-year tale
of dazzling leaps of imagination and extraordinary experiments.
Tens of thousands of volts passed across his body
and through the end of a lamp that he was holding.
It's a story of a maverick geniuses
who used electricity to light our cities,
to communicate across the seas and through the air,
to create modern industry and to give us the digital revolution.
But in this film, we'll tell the story of the very first scientists
who started to unlock the mysteries of electricity.
It's as though there's something alive in there.
They studied its curious link to life,
built strange and powerful instruments to create it
and even tamed lightning itself.
It was these men who truly laid the foundations of the modern world.
And it all started with a spark.
Imagine our world without electricity.
It would be dark,
cold and quiet.
In many ways, it would be like the beginning of the 18th century,
where our story begins.
This is the Royal Society in London.
In the early 1700s, after years in the wilderness,
Isaac Newton finally took control of it
after the death of his arch-enemy, Robert Hooke.
Newton brought in his own people to the key jobs,
to help shore up his new position.
The new head of demonstrations there was 35-year-old Francis Hauksbee.
Notes from the Royal Society in 1705
reveal how hard Hauksbee tried
to stamp his personality on its weekly meetings,
producing ever more spectacular experiments to impress his masters.
In November, he came up with this -
a rotating glass sphere.
He was able to remove the air from inside it using a new machine -
the air pump.
On his machine, a handle allowed him to spin the sphere.
One by one, the candles in the room were put out
and Francis placed his hand against the sphere.
The audience were about to see something amazing.
'Inside the glass sphere,
'a strange ethereal light began to form,
'dancing around his hand.
'A light no-one had ever seen before.'
That's fantastic.
You see a beautiful blue glow, it's just marking out
the shape of my hands, but then going right round the ball.
It's as though there's something alive in there.
It's difficult to really understand
why this dancing blue light meant so much,
but we have to bear in mind that at the time,
natural phenomena like this were seen to be the work of the Almighty.
This was still a period when, even in Isaac Newton's theory,
God was constantly intervening in the conduct of the world.
It made sense for a lot of people
to interpret natural phenomena as acts of God.
So when a mere mortal meddled with God's work,
it was almost beyond rational comprehension.
Hauksbee never realised the full significance of his experiment.
He lost interest in his glowing sphere
and spent the last few years of his life
building ever more spectacular experiments
for Isaac Newton to test his other theories.
He never realised that he had unwittingly started
an electrical revolution.
Before Hauksbee, electricity had been merely a curiosity.
The ancient Greeks rubbed amber, which they called electron,
to get small shocks.
Even Queen Elizabeth I marvelled
at static electricity's power to lift feathers.
But now Hauksbee's machine
could make electricity at the turn of a handle,
and you could see it.
Perhaps even more importantly, his invention coincided
with the birth of a new movement sweeping across Europe
called the Enlightenment.
Enlightened intellectuals used reason to question the world
and their legacy was radical politics,
iconoclastic art
and natural philosophy, or science.
But ironically, Hauksbee's new machine
wasn't immediately embraced by most of these intellectuals.
But instead, by conjurers and street magicians.
Those with an interest in electricity
called themselves electricians.
One story tells of a dinner party attended by an Austrian Count.
The electrician had placed some feathers on the table
and then charged up a glass rod with a silk handkerchief.
He then astonished the guests by lifting up the feathers
with the rod.
He then went on to charge himself up
using one of Hauksbee's electrical machines.
He gave the guests electric shocks, presumably to squeals of delight.
But for his piece de resistance,
he placed a glass of cognac in the centre of the table,
charged himself up again
and lit it with a spark from the tip of his finger.
There was a trick called the electrical beatification,
in which the victim sits on an insulated chair
and above his head hangs a metal crown
that doesn't quite touch his head.
And then if the crown is electrified,
then you get an electric discharge around the crown
that looks exactly like a halo,
which is why it's called the electric beatification.
As England and the rest of Europe went electricity crazy,
the spectacles grew bigger.
The more curious electricians
started to ask more profound questions,
not only how can we make our shows bigger and better,
but how can we control this amazing power?
And for some, can this incredible electrical fire
do more than just entertain?
One of the first early breakthroughs would never have happened
had it not been for a terrible accident.
This is Charterhouse in the centre of London.
Over the past 400 years, it's been a charitable home
for young orphans and elderly gentleman.
And sometime in the 1720s, it also became home to one Stephen Gray.
Stephen Gray had been a successful silk dyer from Canterbury.
He was used to seeing electric sparks leap from the silk
and they fascinated him.
Unfortunately, a crippling accident ended his career
and left him destitute.
But then he was offered a new life here at Charterhouse
and with it the time to perform his own electrical experiments.
Here at Charterhouse, possibly in this very room, the Great Chamber,
Stephen Gray built a wooden frame
and from the top beam he suspended two swings using silk rope.
He also had a device like this, a Hauksbee machine
for generating static electricity.
Now, with a large audience in attendance,
he got one of the orphan boys who lived here at Charterhouse
to lie across the two swings.
Gray placed some gold leaf in front of him.
He then generated electricity
and charged the boy through a connecting rod.
Gold leaf, even feathers, leapt to the boy's fingers.
Some of the audience claimed they could even see sparks
flying out from his fingertips. Show business indeed.
But to the curious and inquiring mind of Stephen Gray,
this said something else as well -
electricity could move,
from the machine to the boy's body, through to his hands.
But the silk rope stopped it dead.
It meant the mysterious electrical fluid
could flow through some things...
..but not through others.
It led Gray to divide the world into two different kinds of substances.
He called them insulators and conductors.
Insulators held electric charge within them
and wouldn't let it move, like the silk or hair,
glass and resin.
Whereas conductors allowed electricity to flow through them,
like the boy or metals.
It's a distinction which is still crucial even today.
Just think of these electric pylons.
They work on the same principle that Gray deduced
nearly 300 years ago.
The wires are conductors.
The glass and ceramic objects
between the wire and the metal of the pylon are insulators
that stop the electricity leaking from the wires
into the pylon and down to the earth.
They're just like the silk ropes in Gray's experiment.
Back in the 1730s,
Gray's experiment may have astounded all who saw it,
but it had a frustrating drawback.
Try as he might, Gray couldn't contain the electricity he was generating for long.
It leapt from the machine to the boy and was quickly gone.
The next step in our story came
when we learnt how to store electricity.
But that would take place not in Britain,
but across the Channel in mainland Europe.
Across the Channel, electricians were just as busy
as their British counterparts and one centre for electrical research
was here in Leiden, Holland.
And it was here that a professor came up with an invention
that many still regard as the most significant of the 18th century,
one that in some form or another can still be found
in almost every electrical device today.
That professor was Pieter van Musschenbroek.
Unlike Hauksbee and Gray,
Musschenbroek was born into academia.
But ironically enough, his breakthrough
came not because of his rigorous science,
but because of a simple human mistake.
He was trying to find a way to store electrical charge,
ready for his demonstrations. And you can almost hear
his train of thought as he tries to figure this out.
If electricity is a fluid that flows, a bit like water,
then maybe you can store it in the same way that you can store water.
So Musschenbroek went to his laboratory
to try to make a device to store electricity.
Musschenbroek started to think literally.
He took a glass jar and poured in some water.
He then placed inside it a length of conducting wire...
..which was connected at the top to a Hauksbee electric machine.
'Then he put the jar on an insulator to help keep the charge in the jar.'
He then tried to pour the electricity into the jar
produced by the machine via the wire
down through into the water.
'But whatever he tried, the charge just wouldn't stay in the jar.
'Then one day, by accident,
'he forgot to put the jar on the insulator,
'but charged it instead while it was still in his hand.'
Finally, holding the jar with one hand,
he touched the top with the other
and received such a powerful electric shock,
he was almost thrown to the ground.
He writes, "It's a new but terrible experiment
"which I advise you never to try. Nor would I, who've experienced it
"and survived by the grace of God do it again
"for all the kingdom of France."
So I'm going to heed his advice, not touch the top,
and instead see if I can get a spark off of it.
The sheer power of the electricity which flew from the jar
was greater than any seen before.
And even more surprisingly,
the jar could store that electricity for hours, even days.
So in honour of the city where Musschenbroek made his discovery,
they called it the Leiden jar.
And its fame swept across the world.
And very rapidly, from 1745 through the rest of the 1740s,
the news of this - it's called the Leiden jar - goes global.
It spreads from Japan in East Asia
to Philadelphia in eastern America.
It became one of the first quick, globalised, scientific news items.
But although the Leiden jar became a global electrical phenomenon,
no-one had the slightest idea how it worked.
You have a jar of electric fluid,
and it turns out that you get a bigger shock from the jar
if you allow the electric fluid to drain away to the earth.
Why is the shock bigger if the jar's leaking?
Why isn't the shock bigger if you make sure all the electric fluid
stays inside the jar?
That was how mid-18th century electrical philosophers
were faced with this challenge.
Electricity was without doubt a fantastical wonder.
It could shock and spark.
It could now be stored and moved around.
Yet what electricity was, how it worked,
and why it did all these things
was nothing less than a complete mystery.
Within 10 years, a new breakthrough was to come
from an unexpected quarter,
From a man politically and philosophically at war
with the London establishment.
And even more shockingly for the British electrical elite,
that man was merely a colonial.
An American.
This painting of Benjamin Franklin
hangs here at the Royal Society in London.
Franklin was a passionate supporter of American emancipation
and saw the pursuit of rational science,
and particularly electricity,
as a way of rolling back ignorance, false idols
and ultimately his intellectually elitist colonial masters.
And this is mixed with a profoundly egalitarian democratic idea
that Franklin and his allies have,
which is this is a phenomenon open to everyone.
Here's something that the elite doesn't really understand
and we might be able to understand it.
Here's something that the elite can't really control
but we might be able to control.
And here's something above all which is the source of superstition.
And we, rational, egalitarian,
potentially democratic, intellectuals,
we will be able to reason it out,
without appearing to be the slaves of magic or mystery.
So Franklin decided to use the power of reason
to rationally explain what many
considered a magical phenomenon...
Lightning.
THUNDER BOOMS
This is probably one of the most famous scientific images
of the 18th century.
It shows Benjamin Franklin, the heroic scientist,
flying a kite in a storm,
proving that lightning is electrical.
But although Franklin proposed this experiment,
he almost certainly never performed it.
Much more likely is that his most significant experiment
was another one which he proposed but didn't even conduct.
In fact, it didn't even happen in America.
It took place here in a small village north of Paris
called Marly La Ville.
The French adored Franklin, especially his anti-British politics,
and they took it upon themselves to perform
his other lightning experiments without him.
I've come to the very spot where that experiment took place.
In May 1752, George Louis Leclerc,
known across France as the Compte de Buffon,
and his friend Thomas Francois Dalibard,
erected a 40-ft metal pole, more than twice as high as this one,
held in place by three wooden staves,
just outside Dalibard's house here in the Marly La Ville.
The metal pole rested at the bottom inside an empty wine bottle.
Franklin's big idea had been that the long pole
would capture the lightning, pass it down the metal rod
and store it in the wine bottle at the base
which worked as a Leiden jar.
Then, he could confirm what lightning actually was.
All his French followers had to do was wait for a storm.
And then on May 23rd, the heavens opened.
THUNDER
At 12.20, a loud thunderclap was heard
as lightning hit the top of the pole.
An assistant ran to the bottle,
a spark leapt across
between the metal and his finger with a loud crack
and a sulphurous smell, burning his hand.
The spark revealed lightning for what it really was.
It was the same as the electricity made by man.
It is hard to overestimate the significance of this moment.
Nature had been mastered, not only that but the wrath of God itself
had been brought under the control of mankind.
It was a kind of heresy.
Franklin's experiment was very important because it showed that
lightning storms produce or are produced by electricity
and that you can bring this electricity down,
that electricity is a force of nature
that's waiting out there to be tapped.
Next, Franklin turned his rational mind to another question.
Why the Leiden jar made the biggest sparks when it was held in the hand?
Why didn't all the electricity just drain away?
In drawing on his experience as a successful businessman,
he saw something no-one else had.
That like money in a bank,
electricity can be in credit, what he called positive,
or debit, negative.
For him, the problem of the Leiden jar is one of accountancy.
Franklin's idea was every body has around an electrical atmosphere.
And there is a natural amount of electric fluid around each body.
If there is too much, we will call it positive.
If there is too little, we will call it negative.
And nature is organised so the positives and negatives
always want to balance out,
like an ideal American economy.
Franklin's insight was that electricity was actually just positive charge
flowing to cancel out negative charge.
And he believed this simple idea
could solve the mystery of the Leiden jar.
As the jar is charged up,
negative electrical charge is poured down the wire and into the water.
If the jar rests on an insulator, a small amount builds up in the water.
But, if instead the jar is held by someone as it is being charged,
positive electric charge
is sucked up through their body from the ground
to the outside of the jar,
trying to cancel out the negative charge inside.
But the positive and negative charges
are stopped from cancelling out
by the glass which acts as an insulator.
Instead, the charge just grows and grows on both sides of the glass.
Then, touching the top of the jar with it the other hand,
completes a circuit allowing the negative charge on the inside
to pass through the hand to the positive on the outside,
finally cancelling it out.
The movement of this charge causes a massive shock and often a spark.
The modern equivalent of the Leiden jar is this - the capacitor.
It is one of the most ubiquitous of electronic components.
It is found everywhere.
There are a number of smaller ones scattered around on this circuit board from a computer.
They help smooth out electrical surges,
protecting sensitive components,
even in the most modern electric circuit.
Solving the mystery of the Leiden jar
and recognising lightning as merely a kind of electricity
were two great successes for Franklin
and the new Enlightenment movement.
But the forces of trade and commerce,
which helped fuel the Enlightenment,
were about to throw up a new
and even more perplexing electrical mystery.
A completely new kind of electricity.
This is the English Channel.
By the 17th and 18th centuries,
a good fraction of the world's wealth flowed up this stretch of water
from all corners of the British Empire
and beyond, on its way to London.
Spices from India, sugar from the Caribbean,
wheat from America, tea from China.
But, of course, it wasn't just commerce.
New plants and animal specimens
from all over the world came flooding into London,
including one that particularly fascinated the electricians.
Called the torpedo fish, it had been the stuff of fishermen's tales.
Its sting, it was said, was capable of knocking a grown man down.
But as the electricians started to investigate the sting,
they realised it felt strangely similar to a shock
from a Leiden jar.
Could its sting actually be an electric shock?
At first, many people dismissed the torpedo fish's shock as occult.
Some said it was probably just the fish biting.
Others that it could not be a shock because, without a spark,
it just wasn't electricity.
But, for most, it was a very strange
and inexplicable new mystery.
It would take one of the oddest
yet most brilliant characters in British science
to begin to unlock the secrets of the torpedo fish.
This is the only picture in existence
of the pathologically shy but exceptional Henry Cavendish.
This one only exists because an artist sketched his coat
as it hung on a peg, then filled in the face from memory.
His family were fantastically rich.
They were the Devonshires
who still own Chatsworth House in Derbyshire.
Henry Cavendish decided to turn his back
on his family's wealth and status
to live in London near his beloved Royal Society
where he could quietly pursue his passion for experimental science.
When he heard about the electric torpedo fish, he was intrigued.
A friend wrote to him...
"On this, my first experience of the effect of the torpedo,
"I exclaimed that this is certainly electricity.
"But how?"
And to work out how a living thing could produce electricity,
he decided to make his own artificial fish.
These are his plans.
Two Leiden jars shaped like the fish which were buried under sand.
When the sand was touched, they discharged, giving a nasty shock.
His model helped convince him that the real torpedo fish was electric.
But it still left him with a nagging problem.
Although both the real fish and Cavendish's artificial one
gave powerful electric shocks,
the real fish never sparked.
Cavendish was perplexed.
How could it be the same kind of electricity
if they didn't both do the same kinds of things?
Cavendish spent the winter of 1773 in his laboratory
trying to come up with an answer.
In the spring, he had a brainwave.
Cavendish's ingenious answer was to point out a subtle distinction
between the amount of electricity and its intensity.
The real fish produced the same kind of electricity.
It is just that it was less intense.
For a physicist like me, this marks a crucial turning point.
But it is the moment when two genuinely innovative scientific ideas first crop up.
What Cavendish refers to as the amount of electricity,
we now call "electric charge".
His intensity is what we call
the potential difference or "voltage".
So the Leiden jar's shock was high-voltage but low charge
whereas the fish was low voltage and high charge.
It's possible to actually measure that.
Hiding at the bottom of this tank under the sand
is the Torpedo marmorata and it's an electric ray.
You can just see its eyes protruding from the sand.
This is a fully grown female
and I am going to try and measure
the electricity it gives off with this bait.
I have a fish connected to a metal rod and hooked up
to an oscilloscope
to see if I can measure the voltage as it catches its prey.
Here goes!
Oh! There's one!
There's another one.
The fish gave a shock of about 240 volts,
the same as mains electricity, but still roughly 10 times less
than the Leiden jar.
That would have given me quite a nasty shock
and I can only try and imagine what it must have been like
for scientists in the 18th century to witness this.
An animal, a fish, producing its own electricity.
Cavendish had shown that the torpedo fish made electricity
but he didn't know if it was the same kind of electricity
as that made from an electrical machine.
Is the electrical shock that a torpedo produces
the same as produced by an electrical machine?
Or are there two kinds?
A kind generated artificially or is there a kind of animal electricity
that only exists in living bodies?
This was a huge debate that divided opinion for several decades.
Out of that bitter debate came a new discovery.
The discovery that electricity needn't be a brief shock or spark.
It could actually be continuous.
And the generation of continuous electricity
would ultimately propel us into our modern age.
But the next step in the story of electricity would come about
because of a fierce personal and professional rivalry
between two Italian academics.
BELL RINGS
This is Bologna University, one of the oldest in Europe.
In the late 18th century,
the city of Bologna was ruled from papal Rome
which meant that the university was powerful
but conservative in its thinking.
It was steeped in traditional Christianity,
one where got ruled earth from heaven
but that the way he ran the world
was hidden from us mere mortals
who were not meant to understand him,
only to serve him.
One of the university's brightest stars
was the anatomist Luigi Aloisio Galvani.
But, in a neighbouring city,
a rival electrician was about to take Galvani to task.
This is Pavia, only 150 miles from Bologna,
but by the end of the 18th century,
worlds apart politically.
It was part of the Austrian empire which put it
at the very heart of the European Enlightenment.
Liberal in its thinking, politically radical
and obsessed with the new science of electricity.
It was also home to Alessandro Volta.
Alessandro Volta couldn't have been more unlike Galvani.
From an old Lombardi family, he was young, arrogant, charismatic,
a real ladies' man,
and he courted controversy.
Unlike Galvani, he liked to show off his experiments
on an international stage to any audience.
Volta's ideas were unfettered by Galvani's religious dogma.
Like Benjamin Franklin and the European Enlightenment,
he believed in rationality -
that scientific truth,
like a Greek god, would cast ignorance to the floor.
Superstition was the enemy. Reason was the future.
Both men were fascinated by electricity.
Both brought their different ways of seeing the world to bear on it.
Galvani had been attracted to the use of electricity
in medical treatments.
For instance, in 1759, here in Bologna,
electricity was used on the muscles of a paralysed man.
One report said,
"It was a fine sight to see the mastoid rotate the head,
"the biceps bend the elbow.
"In short, to see the force and vitality of all the motions
"occurring in every paralysed muscle subjected to the stimulus."
Galvani believed these kinds of examples
revealed that the body worked using animal electricity,
a fluid that flows from the brain,
through the nerves, into the muscles,
where it's turned into motion.
He devised a series of grisly experiments to prove it.
Now, he first prepared a frog.
He writes, "The frog is skinned and disembowelled.
"Only their lower limbs are left joined together,
"containing just the crural nerves."
I've left my frog mostly intact,
but I've exposed the nerves that connect to the frog's legs.
Then he used Hauksbee's electrical machine
to generate electrostatic charge,
that would accumulate and travel along this arm
and out through this copper wire.
Then he connected the charge-carrying wire to the frog
and another to the nerve just above the leg.
Let's see what happens.
Ooh! And the frogs leg twitches, just as it makes contact.
There we go!
For Galvani, what was going on there was that there's a strange,
special kind of entity in the animal muscle,
which he calls animal electricity.
It's not like any other electricity. It's intrinsic to living beings.
But for Volta, animal electricity smacked of superstition and magic.
It had no place in rational and enlightened science.
Volta saw the experiment completely differently to Galvani.
He believed it revealed something totally new.
For him, the legs weren't jumping as a result
of the release of animal electricity from within them,
but because of the artificial electricity from outside.
The legs were merely the indicator.
They were only twitching because of the electricity from the Hauksbee machine.
Back in Bologna, Galvani reacted furiously to Volta's ideas.
He believed Volta had crossed a fundamental line -
from electrical experiments into God's realm,
and that was tantamount to heresy.
To have a kind of spirit like electricity,
to have that produced artificially
and to say that spirit, that living force,
that agency was the same as something produced by God,
that God had put into a living human body or a frog's body,
that seemed sacrilegious to them,
because it was eliminating this boundary
between God's realm of the divine
and the mundane realm of the material.
Spurred on by his religious indignation,
Galvani announced a new series of experimental results,
which would prove Volta was wrong.
During one of his experiments, he hung his frogs on an iron wire
and saw something totally unexpected.
If he connected copper wire to the wire the frog was hanging from,
and then touched the other end of the copper to the nerve...
..it seemed to him he could make the frog's legs twitch
without any electricity at all.
Galvani came to the conclusion that it must have been
something inside the frogs, even if dead,
that continued for a while after death
to produce some kind of electricity.
And the metal wires were somehow releasing that electricity.
Over the next months,
Galvani's experiments focused on isolating this animal electricity
using combinations of frog and metal,
Leiden jars and electrical machines.
For Galvani, these experiments were proof the electricity
was originating within the frog itself.
The frog's muscles were Leiden jars, storing up the electrical fluid
and then releasing it in a burst.
On 30th October, 1786, he published his findings in a book,
Animali Electricitate - Of Animal Electricity.
Galvani was so confident of his ideas,
he even sent a copy of his book to Volta.
But Volta just couldn't stomach Galvani's idea of animal electricity.
He thought the electricity just had to come from somewhere else.
But where?
In the 1790s, here at the University of Pavia,
almost certainly in this lecture theatre, which still bears his name,
Volta began his search for the new source of electricity.
His suspicions focused on the metals
that Galvani had used to make his frog's legs twitch.
His curiosity had been piqued by an odd phenomenon he come across -
how combinations of metals tasted.
He found that if he took two different metal coins
and placed them on the tip of his tongue,
and then placed a silver spoon on top of both...
..he got a kind of tingling sensation,
rather like the tingling you'd get from the discharge of a Leiden jar.
Volta concluded he could taste the electricity
and it must be coming from the contact between the different metals in the coins and spoon.
His theory flew in the face of Galvani's.
The frog's leg twitched, not because of its own animal electricity,
but because it was reacting to the electricity from the metals.
But the electricity his coins generated was incredibly weak.
How could he make it stronger?
Then an idea came to him as he revisited the scientific papers
from the great British scientist, Henry Cavendish,
and in particular, his famous work on the electric torpedo fish.
He went back and took a closer look at the torpedo fish
and in particular, the repeating pattern of chambers in its back.
He wondered whether it was this repeating pattern
that held the key to its powerful electric shock.
Perhaps each chamber was like his coins and spoon,
each generating a tiny amount of electricity.
And, perhaps, the fish's powerful shock
results from the pattern of chambers repeating over and over again.
With growing confidence in his new ideas, Volta decided to fight back
by building his own artificial version of the torpedo fish.
So, he copied the torpedo fish by repeating its pattern,
but using metal.
Here's what he did - he took a copper metal plate
and then placed above it a piece of card soaked in dilute acid.
Then above that, he took another metal and placed it on top.
What he had here was exactly the same thing as Galvani's two wires.
But now Volta repeated the process.
What he was doing here was building a pile of metal.
In fact, his invention became known as the pile.
But it's what it could do that was the really incredible revelation.
Volta tried his pile out on himself by getting two wires
and attaching them to each end of the pile
and bringing the other ends to touch his tongue.
He could actually taste the electricity.
This time, it was more powerful than normal and it was constant.
He'd created the first battery.
The machine was no longer an electrical and mechanical machine,
it was just purely an electrical machine.
So he proved that a machine imitating the fish could work,
that what he called the metal or contact electricity
of different metals could work,
and that he regarded as his final,
winning move in the controversy with Galvani.
What Volta's pile showed was that you could develop all the phenomena
of animal electricity without any animals being present.
So, from the Voltaic point of view, it seemed as if Galvani was wrong,
there's nothing special about the electricity in animals.
It's electricity and it can be completely mimicked
by this artificial pile.
But the biggest surprise for Volta was that the electricity it generated was continuous.
In fact, it poured out like water in a stream.
And just as in a stream, where the measure of the amount of water
flowing is called a current, so the electricity flowing
out of the pile became known as an electrical current.
200 years after Volta,
we finally understand what electricity actually is.
The atoms in metals, like all atoms, have electrically charged
electrons surrounding a nucleus.
But in metals, the atoms share their outer electrons
with each other in a unique way,
which means they can move from one atom to the next.
If those electrons move in the same direction at the same time,
the cumulative effect is a movement of electric charge.
This flow of electrons is what we call an electric current.
Within weeks of Volta publishing details of his pile,
scientists were discovering something incredible about what it could do.
Its effect on ordinary water was completely unexpected.
The constant stream of electric charge into the water
was ripping it up into its constituent parts -
the gases, oxygen and hydrogen.
Electricity was heralding the dawn of a new age.
A new age where electricity ceased being a mere curiosity
and started being genuinely useful.
With constant flowing current electricity,
new chemical elements could be isolated with ease.
And this laid the foundations for chemistry, physics and modern industry.
Volta's pile changed everything.
The pile made Volta an international celebrity,
feted by the powerful and the rich.
In recognition,
a fundamental measure of electricity was named in his honour.
The volt.
But his scientific adversary didn't fare quite so well.
Luigi Aloisio Galvani died on 4th December 1798,
depressed and in poverty.
For me, it's not the invention of the battery
that marked the crucial turning point in the story of electricity,
it's what happened next.
It took place in London's Royal Institution.
It was the moment that marked the end of one era
and the beginning of another.
It was overseen by Humphry Davy,
the first of a new generation of electricians.
Young, confident and fascinated by the possibilities of continuous electrical current.
So, in 1808, he built the world's largest battery.
It filled an entire room underneath the Royal Institution.
It had over 800 individual voltaic piles attached together.
It must have hissed and breathed sulphurous fumes.
In a darkened room, lit by centuries-old technology, candles and oil lamps,
Davy connected his battery to two carbon filaments
and brought the tips together.
The continuous flow of electricity from the battery
through the filaments leapt across the gap,
giving rise to a constant and blindingly bright spark.
Out of the darkness came the light.
Davy's arc light truly symbolises the end of one era
and the beginning of our era.
The era of electricity.
But there's a truly grisly coda to this story.
In 1803, Galvani's nephew, one Giovanni Aldini,
came to London with a terrifying new experiment.
A convicted murderer called George Forster
had just been hanged in Newgate.
When the body was cut down from the gallows,
it was brought directly to the lecture theatre,
where Aldini started his macabre work.
Using a voltaic pile,
he began to apply an electric current to the dead man's body.
Then Aldini put one electrical conductor in the dead man's anus
and the other at the top of his spine.
Forster's limp, dead body sat bolt upright
and his spine arched and twisted.
For a moment, it seemed as though the dead body
had been brought back to life.
It appeared as though electricity might have the power of resurrection.
And this made a profound impact on a young writer called Mary Shelley.
Mary Shelley wrote one of the most powerful and enduring stories ever.
Based partly here on Lake Como,
Frankenstein tells the story of a scientist,
a Galvanist probably based on Aldini,
who brings a monster to life using electricity.
And then, disgusted by his own arrogance, he abandons his creation.
Just like Davy's arc lamp, this book symbolises changing times.
The end of the era of miracles and romance
and the beginning of the era of rationality, industry and science.
And it's that new age we explore in the next programme,
because at the start of the 19th century,
scientists realised electricity was intimately connected
with another of nature's mysterious forces...
magnetism.
And that realisation would completely transform our world.
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
E-mail subtitling@bbc.co.uk