(Explosion)
MAN: "Now the substance of cinnbar is such that the more it is heated,
the more exqisite are its sblimatibns
Cinnabar will become mercry
and passing throgh a series of other sblimatibns it is again trned into cinnabar
and ths it enables man to enjoy eternal life"
This is the classical experiment with which alchemists in the Middle Ages
inspired awe in those who watched them, all the way from China to Spain.
They took the red dye, cinnabar, which is a sulphide of mercury,
and heated it.
The heat drives off the sulphur and leaves behind
an exquisite pearl of the mysterious silver liquid metal, mercury,
to astonish and strike awe into the patron.
It's not an experiment of any importance in itself, although it happens that sulphur and mercury
are the two elements of which the alchemists thought the universe is composed.
But it does show one important thing:
That fire has always been regarded, not as the destroying element,
but as the transforming element.
That's been the magic of fire.
I remember Aldous Huxley talking to me through a long evening,
his white hands held into the fire saying,
"This is what transforms. These are the legends that show it.
Above all, the legend of the phoenix that is reborn in the fire
and lives over and over again in generation after generation."
Fire is the image of youth and blood,
the symbolic colour in the ruby and cinnabar.
And when Prometheus in Greek mythology brought fire to man, he gave him life.
In a more practical way, fire has been known to early man for about 400,000 years, we think.
It's certainly found in the caves of Peking man.
Every culture since then has used fire.
And used it to make the simple transformations of everyday life.
To cook, to dry and harden wood, to heat and split stones.
But of course, the great transformation that helped to make civilisation goes deeper.
Physics is the knife that cuts into the grain of nature.
Fire, the flaming sword, is the knife that cuts below the visible structure into the stone.
That is, the extraction of metals from their ores,
which we now know was begun 7,500 years ago, about the year 5500 BC
in Persia and Afghanistan.
At that time, men put the green stone malachite into the fire in earnest,
and from it flowed the red metal copper.
They recognised copper because it's sometimes found in raw lumps on the surface,
and in that form, it had been hammered and worked for over 2,000 years already.
The New World too, worked copper and smelted it by the birth of Christ,
but it stopped there.
Only the Old World went on to make metal the backbone of civilised life.
Suddenly, the range of man 's control is increased immensely.
He has at his command, a material which can be moulded, drawn, hammered, cast,
which can be made into a tool, an ornament, a vessel,
and which can be thrown back into the fire and reshaped.
It has only one shortcoming.
Copper is a soft metal.
As soon as it's put under strain, a copper wire, for instance, it visibly begins to yield.
That's because copper, like every metal, is made up of layers of crystal.
And it's the crystal layers which slide over one another until finally they part.
When the copper wire necks, it's not so much that it fails in tension,
as that it fails by internal slipping.
Of course, the coppersmith did not think like that.
He was faced with a robust problem, which is that copper will not take an edge.
For a short time, the ascent of man stood poised at the next step,
to make a hard metal with a cutting edge.
If that seems a large claim for a technical advance,
that's because, as a discovery, the next step is so paradoxical and beautiful.
When, to copper, you add an even softer metal, tin, you make an alloy which is harder than iron.
You make bronze.
The point is that almost any pure material is weak.
What tin does is to add to the pure material a kind of atomic grit,
points of a different roughness which stick in the crystal lattice and stop it from sliding.
That discovery reached its finest expression in China.
It had come to China almost certainly from the Middle East,
where bronze was discovered about 3800 BC.
The high period of bronze in China
is also the beginning of Chinese civilisation as we think of it.
The Shang dynasty, before 1500 BC.
The Shang dynasty is a time when ceramics are also developed
and writing becomes fixed.
It's the calligraphy, both on the ceramics and the bronze, which is so startling.
The Chinese made the mould out of strips shaped round a ceramic core.
And because the strips are still found, we know how the process worked.
The proportions of copper and tin that the Chinese used are fairly exact.
Bronze can be made from almost any proportion,
between, say, 5% and 20% of tin.
But the best Shang bronzes are held at 15% of tin,
and there the sharpness of the casting is perfect.
At that proportion, bronze is almost three times as hard as copper.
This is a ritual vessel in which drink is offered to the gods.
The Shang bronzes are ceremonial, divine objects.
They express for China a monumental worship,
which in Europe at that same moment, was building Stonehenge.
Bronze becomes, from this time onwards, a material for all purposes.
The plastic of its age.
The delight of these Chinese works, vessels for wine and food, in part playful,
in part divine,
is that they form an art that grows spontaneously out of its own technical skill.
The scientific content of these classical techniques is clear cut.
With the discovery that fire will smelt metals,
comes in time the discovery that it will fuse them together to make an alloy with new properties.
That's as true of iron as of copper.
Iron is, of course, a much later discovery.
The first positive evidence is probably a piece of a tool
that's been stuck in one of the pyramids, and that gives us a date of around 2500 BC.
But the wide use of iron is really initiated by the Hittites round the Black Sea around 1500 BC,
just the time of the process of casting bronze in China, the time of Stonehenge.
And as copper comes of age in its alloy bronze, so iron comes of age in its alloy steel.
Within 500 years, by 1000 BC, steel is being made in India.
And the exquisite properties of different kinds of steel come to be known.
They reach their climax, for me, in the making of the Japanese sword,
which has been going on in one way or another since perhaps 800 AD.
The making of the sword, like all ancient metallurgy, is surrounded with ritual
and that's for a clear-cut reason.
When you have no written language, when you have no symbolism,
when you have nothing that can be called a chemical formula,
then you must have a precise ceremony
which fixes the sequence of operations so that they are exact and memorable.
So, there's a kind of laying on of hands, an apostolic succession,
by which one generation blesses and gives to the next the materials,
blesses the fire, and blesses the sword-maker.
The man who is making this sword holds the title of a Living Cultural Monument.
His name is Getsu,
and in a formal sense, he's a direct descendant in his craft of the sword-maker Masamune,
who perfected the process in the 13th century to repel the Mongols.
Iron is a later discovery than copper because at every stage it needs more heat.
The melting point of iron is about 1,500 degrees centigrade.
Steel is a material infinitely more sensitive than bronze.
In it, iron is alloyed with a tiny percentage of carbon.
Less than 1%, usually.
The process of making the sword
reflects the exquisite control of carbon and of heat treatment
by which a steel object is made to fit its function perfectly.
Even the steel billet is not simple
because a sword must combine two different, and incompatible, properties of materials.
A sword must be flexible and yet it must be hard.
Those are not properties which can be built into the same material, unless it consists of layers.
The steel billet is cut and then doubled over, so as to make a multitude of inner surfaces.
The sword that Getsu makes requires him to double the billet 15 times.
That means that the number of layers of steel will be two to the power of 15,
which is well over 30,000 layers.
Each layer must be bound to the next, which has a different property.
It's as if we were trying to combine the flexibility of rubber with the hardness of glass.
And the sword, essentially, is an immense sandwich of these two properties.
At the last stage, the sword is prepared by being covered with clay to different thicknesses,
so that when it's heated and plunged into the water,
it will cool at different rates.
The temperature of the steel for this final moment has to be judged precisely.
And in a civilisation in which that's not done by measurement, there is naturally a ritual formula.
The sword is to be heated until it glows to the colour of the morning sun.
The climax, not so much of drama as of chemistry, is the quenching,
which hardens the sword and fixes the different properties within it.
Different crystal sizes are produced by the different rates of cooling.
Large smooth crystals, at the flexible core of the sword,
and small jagged crystals at the cutting edge.
The two properties of rubber and glass are finally combined in the finished sword.
They reveal themselves in the surface appearance of the sword,
a sheen of shot silk by which the Japanese set high store.
But the test of a sword,
the test of a technical practice that has some scientific theory, is "Does it work?"
Can it cut the human body in the formal ways that ritual lays down.
Cut number two, the O-jo-dan.
The body is simulated by packed straw - nowadays.
The sword is the weapon of the samurai.
By the sword, they survived the endless civil wars
that divided Japan from the 12th century on.
Everything about them is fine metalwork.
The flexible armour made of steel strips, the horse trappings, the stirrup.
And yet the samurai did not know how to make any of these things themselves.
Like the horsemen in other cultures, they lived by force
and depended, even for their weapons,
on the skill of villagers whom they alternately protected and robbed.
In the long run, the samurai became a set of paid mercenaries
who sold their services for gold.
Gold is the universal prize in all countries, in all cultures, in all ages.
MAN: Gold rosary, 16th century, English.
Gold serpent brooch 400 BC Greek
Triple gold crown of Abna 17th centry Abyssinian
Gold snake bracelet
FRANCIS BACON: "Gold hath these natures,
greatness of weight closeness of parts fixatibn
pliantness or softness immnity from rst color or tinctre of yellow
If a man can make a metal that hath all these properties
let men dispte whether it be gold or no"
MAN: rital vessels of Achaemenid gold 6th centry BC Persian
Drinking bowl of Malik gold 8th centry BC Persian BII's heads
KO-HUNG: "Yellow gold if melted a hndred times
will not be spoiled nor will it rot ntil the end of the world"
MAN: Pre-inca. Peruvian, 9th century.
BRONOWSKl: The touch of Midas.
Gold for greed.
Gold for splendour.
Gold for adornment.
Gold for reverence.
Gold for power.
Sacrificial gold.
Life-giving gold.
Gold for tenderness.
Barbaric gold.
Voluptuous gold.
MAN:
MAN: Benvenuto Cellini, 16th century...
CELLINl: "When I set this work before the king
he gasped in amazement and cold not take his eyes off it
He cried in astonishment
'T his is 100 times more heavenly than I wold ever have thoght What a marvel the man is"
BRONOWSKl: It's easy to see that the man who made a gold artefact
was not just a technician, but an artist.
But it's equally important and not so easy to recognise that the man who assayed gold
was also more than a technician.
To him, gold was an element of science.
Having a technique is useful, but like every skill,
what brings it to life is its place in a general scheme of nature.
A theory.
Men who tested and refined gold made visible a theory of nature.
A theory in which gold was unique and yet might be made from other elements.
That's why so much of antiquity spent its time and ingenuity in devising tests for pure gold.
This is a precise test by cupellation.
A bone-ash vessel, or cupel, is heated in the furnace
and brought up to a temperature much higher than pure gold requires.
The gold with its impurities, or dross, is put in the vessel and melts.
Gold has quite a low melting point,
just over 1,000 degrees centigrade, almost the same as copper.
What happens now is that the dross leaves the gold and is absorbed into the walls of the vessel,
so that all at once there's a visible separation between, as it were,
the dross of this world and the hidden purity of the gold in the flame.
The dream of the alchemists, to make synthetic gold,
has in the end to be tested by the reality of this pearl of gold that survives the assay.
The first written reference we have to alchemy is just over 2,000 years old
and it comes from China.
It tells how to make gold, and to use it to prolong life.
That's an extraordinary conjunction to us.
To us, gold is precious because it's scarce.
But to the alchemists all over the world, gold was precious because it was incorruptible.
No acid or alkali known to those times would attack it.
That indeed is how the emperor's goldsmiths assayed, or as they would have said, parted, it.
At a time when life was thought to be brutal, short, dirty,
to the alchemists, gold represented the one eternal spark of life in the human body.
And their search to transmute base metals into gold and to find the elixir of life
are one and the same endeavour.
There lies, therefore, in their work, a profound theory.
One which derives in the first place, of course, from Greek ideas about earth, fire, air and water,
but which, by the Middle Ages, has taken on a new and very important form.
To the alchemists then, there was a sympathy
between the microcosm of the human body and the macrocosm of nature.
A volcano on a grand scale was like a boil.
A tempest and rainstorm was like a fit of weeping.
Under these superficial analogies,
and every scientific theory is an analogy,
lay the deeper principle, which is that the universe and the body
are made of the same materials, or principles, or elements.
To the alchemists, there were two such principles.
One was mercury, which stood for everything which is dense and permanent.
The other was sulphur,
which stood for everything which is inflammable and impermanent.
All material bodies, including the human body were made from these two principles
and could be remade from them.
For instance, they believed that all metals grow inside the earth from mercury and sulphur,
the way the bones grow inside an embryo from the egg.
And they really meant that analogy.
It still remains, in the symbol of medicine now.
We still use for the female the alchemical sign for copper,
that is what is soft, Venus.
And we use for the male the alchemical sign for iron,
that is what is hard, Mars.
That seems a terribly childish theory today.
But our chemistry will seem childish 500 years from now.
A theory, in its day, helps to solve the problems of the day.
And the medical problems had been hamstrung until about 1500,
by the belief of the ancients that all cures must come either from plants or from animals,
a kind of vitalism.
Now the alchemists introduced minerals into medicine.
Salt, for example.
And, a very characteristic cure for a disease which raged round Europe in 1500
and had not been known before.
The new scourge, syphilis.
To this day, we don 't know where syphilis came from.
It may have been brought back by the sailors in Columbus's ships.
The cure for it turned out to depend on the use of the most powerful alchemical metal,
mercury.
The man who made that cure work is a landmark from the old alchemy to the new,
on the way to chemistry, iatrochemistry, biochemistry, the chemistry of life.
He worked in Europe in the 16th century.
The place is Basel in Switzerland.
The year is 1527.
There is an instant in the ascent of man
when he steps out of the shadow land of secret and anonymous knowledge
into the new system of open and personal discovery.
The man that I have chosen to symbolise it
was christened Aureolus Philippus Theophrastus Bombastus Von Hohenheim.
Happily, he gave himself the somewhat more compact name of Paracelsus.
He was a Rabelaisian, picaresque, wild character,
drank with students, ran after women, travelled all over the world...
...and until recently, figured in the histories of science as a quack.
But that he was not.
He was a man of divided, but profound, genius.
He was a practical man who understood that the treatment of a patient depends on diagnosis,
he was a brilliant diagnostician,
and on direct application by the doctor himself, he broke with the tradition
by which the physician was a learned academic
who read out of a very old book,
and the poor patient was in the hands of some assistant, who did what he was told.
That's how he came to be brought here.
This is the house, in Basel, of Johann Frobenius,
the great Protestant and humanist printer...
...who in 1527, had a serious leg infection, was about to be amputated,
appealed to his friends in the new movement, who sent him Paracelsus.
Paracelsus threw the academics out of the room
saved the leg and effected a cure which echoed through Europe.
Erasmus wrote to him, saying:
"You have brought back Frobenius, who is half my life, from the underworld."
The focus of that historic time was Basel.
Think of the dates.
Paracelsus was born in 1493.
That was the year after Columbus had discovered America
and opened the New World.
Then came Luther,
exploding the traditions of the Church,
and here in Basel setting town against gown in a new kind of opposition.
Humanism had flourished even before the Reformation.
There was a university with a democratic tradition,
so that although its medical men looked askance at Paracelsus,
the city council could insist that he be allowed to teach.
A great change was blowing up in Europe.
Greater perhaps even than the religious and political upheaval
that Martin Luther had set going.
The symbolic year of destiny was just ahead:
1543.
In that year three books were published that changed the mind of Europe.
The anatomical drawings of Vesalius;
the first translation of the Greek mathematics and physics of Archimedes;
and the book by Nicolaus Copernicus on The Revolution Of The Heavenly Orbs,
which put the sun at the centre of the heaven
and created what is now called the Scientific Revolution.
(Bells ringing)
All that battle between past and future is summarised prophetically in 1527
in a single action outside the minster here at Basel.
Paracelsus publicly threw into the traditional student bonfire
an ancient medical textbook by Avicenna, an Arab follower of Aristotle.
There is something symbolic about that midsummer bonfire
which I will try to conjure into the present.
Fire is the alchemists' element,
by which man is able to cut deeply into the structure of matter.
Then is fire itself a form of matter?
If you believe that,
you have to give it all sorts of impossible properties.
Such as that it is...
lighter than nothing.
200 years after Paracelsus
that is what chemists tried to do in the theory of phlogiston.
But there is no such substance as phlogiston,
just as there is no such principle as the vital principle,
because fire is not material, any more than life is material.
Fire is a process of transformation and change,
by which material elements are rejoined into new combinations.
The nature of chemical processes was only understood
when fire itself came to be understood as a process.
The gesture of Paracelsus had said,
"Science cannot look back to the past.
There never was a golden age."
It took another 250 years to discover the new element oxygen,
which at last explained the nature of fire,
and took chemistry forward out of the Middle Ages.
I'm in the Smithsonian in Washington,
in what remains of Priestley's laboratory.
Of course, I have no business to be here.
This apparatus ought to be in Birmingham, in England,
where Priestley did his most splendid work - the centre of the Industrial Revolution.
Why is it here?
Because a mob drove Priestley out of Birmingham in 1791.
I would like to be able to tell you that the mob that destroyed Priestley's house in Birmingham
shattered the dream of a beautiful, lovable, charming creature.
Alas, I doubt if that would really be true.
I don 't think that Priestley was very lovable.
I suspect that he was a rather difficult, cold, cantankerous,
precise, prim, puritanical man.
But the ascent of man is not made by lovable people.
It's made by people who have two qualities:
An immense integrity
and at least a little genius.
The discovery that he made was that air is not an elementary substance.
That it's composed of several gases,
and that among those, oxygen -
what he called dephlogisticated air -
is the one that is essential to the life of animals.
On 1 st August 1774, he made some oxygen,
and saw, to his astonishment, how brightly a candle burned in it.
In October of that year he went to Paris,
he asked Lavoisier and many others about it,
but it was not until he himself came back
and on the 8th March 1775, put a mouse into oxygen
that he realised how well one breathed in that.
A day or two after, he wrote a delightful letter. He said to Franklin:
"Two mice and I are the only creatures who've had the exquisite pleasure of breathing it."
He also discovered that the plants breathe out oxygen in sunlight.
Of course, that is the basis of the animals who breathe it in.
The next hundred years were to show this was crucial,
that animals would not have evolved at all if the plants hadn 't made the oxygen first.
But, of course, in the 1770s, nobody had thought of that.
The discovery of oxygen was given meaning by the clear revolutionary mind of Lavoisier,
who perished in the French Revolution.
Lavoisier repeated an experiment of Priestley's,
which is almost a caricature of one of the classical experiments of alchemy.
Both men heated the red oxide of mercury using a burning glass -
the burning glass was fashionable just then -
in a vessel in which they could see gas being produced and could collect it.
The gas was oxygen.
That was the qualitative experiment,
but to Lavoisier it was the instant clue
that chemical decomposition could be quantified.
The idea was simple and radical:
Run the experiment in both directions
and measure the quantities exactly.
Burn mercury so that it absorbs oxygen,
and measure the exact quantity of oxygen that is taken up
between the beginning of the burning and the end.
Now turn the process into reverse.
Take the mercuric oxide that has been made,
heat it vigorously and expel the oxygen from it again.
Mercury is left behind, oxygen flows into the vessel,
and the crucial question is: How much?
Exactly the amount that was taken up before.
Suddenly the process is a material one.
Essences, principles, phlogiston have disappeared,
two concrete elements have really been put together and taken apart.
After the fire, the sulphur, the burning mercury,
it was inevitable that the climax of the story
should take place in the chill damp of Manchester.
Here, between 1803 and 1808,
a Quaker schoolmaster called John Dalton
turned the vague knowledge of chemical combination,
brilliantly illuminated as it had been by Lavoisier,
suddenly into the precise modern conception of atomic theory.
It was a time of marvellous discovery in chemistry.
In those five years, ten new elements were found.
And yet, Dalton was not interested in any of that.
He was, to tell the truth, a somewhat colourless man.
He was certainly colour-blind.
He was a man of regular habits,
who walked out every Thursday afternoon to play bowls in the countryside.
And the things he was interested in were the things of the countryside,
the things in Manchester - water, marsh gas, carbon dioxide.
And he asked himself concrete questions about the way they combined by weight.
Why, when water is made of oxygen and hydrogen,
do exactly the same amounts always come together to make a given amount of water?
Why when carbon dioxide is made, why when methane is made,
are there these constancies of weight?
And he suddenly realised that the answer must be
that yes, old-fashioned Greek atomic theory is true,
but the atom is not just an abstraction in a physical sense,
it has a weight which characterises that element or that element.
In 1805, he published for the first time his conception of it.
And it looked like this.
If a given quantity of carbon...
...an atom...
combines to make carbon dioxide, it does so with two atoms of oxygen.
If water is constructed from oxygen and hydrogen,
it will be that molecule of water and that molecule of water.
The weights are right.
Now are the weights right for methane?
Yes - exactly, if you remove those oxygens.
You have the right quantities of hydrogen and carbon to make methane.
It is the exact arithmetic of the atoms
which makes of chemical theory the foundations of modern atomic theory.
That's the first profound lesson that comes out of all this multitude of speculation
about gold and copper and alchemy,
until it reaches its climax in Dalton.
The other is a point about scientific method.
Dalton was a man of regular habits.
Measured the rainfall, the temperature...
a singularly monotonous enterprise in this climate.
Of all that mass of data, nothing whatever came.
But of the one searching, almost childlike, question
about the weights that enter the construction of these simple molecules...
Out of that came modern atomic theory.
That's the essence of science.
Ask an impertinent question,
and you're on the way to the pertinent answer.