THE ASCENT OF MAN

 JACOB BROWNOWSKI

MACDONALD FUTURA PUBLISHERS                        1973

PART IV

 

Chapter 4: The Hidden Structure

• Fire has been known to man for about 400,000 years. The coppersmith 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.
• It is only in the last 50 years that we have come to understand that the special properties of alloys derive from their atomic structure. And yet by luck or by experiment, the ancient smelters found that when you add to copper an even softer metal, tin, you make an alloy which is harder and more durable than either – bronze.
• Almost any pure material is weak; impurities make it stronger. As copper comes of age in its alloy, bronze, so iron comes of age in its alloy, steel.
• Within five hundred years, by 1000 BC, steel is being made in India, and the exquisite properties of different kinds of steel come to be known.
• As late as two hundred years ago, the steel industry of Sheffield was still small and backward, and the Quaker Benjamin Huntsman, wanting to make a precision watch-spring, had to turn metallurgist and discover how to make the steel for it himself.
• I will take an Oriental example also of the techniques that produce the special properties of steel. They reach their climax, for me, in the making of the Japanese sword, which has been going on in one way or another since AD 800.
• The making of the sword, like all ancient metallurgy, is surrounded with ritual, and that is for a clear reason.
• When you have no written language, when you have nothing that can be called a chemical formula, then you must have a precise ceremonial which fixes the sequence of operations so that they are exact and memorable.
• So there is 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 was making this sword holds the title of a ‘Living Cultural Monument’, formally awarded to the leading masters of ancient arts by the Japanese government.
• His name is Getsu. And in a formal sense, he is the direct descendant in his craft of the sword-maker Masamune, who perfected the process in the 13^th century – to repel the Mongols.
• Or so tradition has it; certainly the Mongols at that time repeatedly tried to invade Japan from China, under the command of the grandson of Genghis Khan, the famous Kublai Khan.
• The process of making the sword reflects the delicate control of carbon and of heat treatment by which a steel object is made to fit its function perfectly. The sword that Getsu makes requires him to double the billet fifteen times.
• This means that the number of layers of steel will be 2 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 is as if he 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 is heated and plunged into water it will cool at different rates. The temperature of the steel for this final moment has to be judged precisely, and in a civilization in which that is not done by measurement, ‘it is the practice to watch the sword being 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 shapes and sizes are produced by 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 fused in the finished sword.
• But the test of the sword, the test of a technical practice, the test of scientific theory, is ‘Does it work?’ Can it cut the human body in the formal ways that ritual lays down?
• The traditional cuts are mapped as carefully as the cuts of beef on a diagram in a cookery book: ‘Cut number two – the O-jo-dan.’ The body is simulated by packed straw, nowadays. But in the past a new sword was tested more literally, by using it to execute a prisoner.
• The sword is the weapon of the Samurai. By it they survived endless civil wars that divided Japan from the 12^th century on. Everything about them is fine metalwork: the flexible armour made of steel strips, the horse trappings, the stirrups.
• 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.
• Our understanding of how the material world is put together from its elements derives from two sources. One, that I have traced, is the development of techniques for making and alloying useful metals.
• The other is alchemy, and it has a different character. It is small in scale, is not directed to daily uses, and contains a substantial body of speculative theory.
• For reason which are oblique but not accidental, alchemy was much occupied with another metal, gold, which is virtually useless.
• Yet gold has so fascinated human societies that I should be perverse if I did not try to isolate the properties that gave it is symbolic power.
• Gold is the universal prize in all countries, in all cultures, in all ages. A representative collection of gold artifacts reads like a chronicle of civilizations.
• The Spaniards plundered Peru for its gold, which the Inca aristocracy had collected as we might collect stamps, with 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 …
• It is easy to see that the man who made a gold artefact was not just a technician, but an artist. But it is equally important, and not so easy to recognize, 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.
• The gold, with its impurities or dross, is put in the vessel and melts. The dross leaves the gold and is absorbed into the walls of the vessel: so that all at once there is a visible separation between, as it were, the dross of this world and the hidden purity of the gold in the flame.
• The ability of gold to resist what was called decay (what we would call chemical attack) was singular, and therefore both valuable and diagnostic.
• To us gold is precious because it is scarce; but to the alchemists, all over the world, gold was precious because it was incorruptible.
• When life was thought to be (and for most people was) solitary, poor, nasty, brutish, and short, to the alchemists gold represented the one eternal spark in the human body.
• Their search to make gold and to find the elixir of life are one and the same endeavour. Gold is the symbol of immortality. In the thought of the alchemists gold was the expression, the embodiment of incorruptibility, in the physical and in the living world together.
• Alchemy is much more than a set of mechanical tricks or a vague belief in sympathetic magic. It is from the outset a theory of how the world is related to human life.
• To the alchemists there was a sympathy between the microcosm of the human body and the macrocosm of nature.
• Our chemistry will seem childish 500 years from now. Every theory is based on some analogy, and sooner or later the theory fails because the analogy turns out to be false. A theory in its day helps to solve the problems of the day.
• The alchemists freely introduced minerals into medicine. He developed a cure for a disease which raged round Europe in 1500 and had not been known before, the new scourge syphilis. To this day we do not know where syphilis came from.
• The man who made that cure work is a landmark in the change from the old alchemy to the new, on the way towards modern chemistry: iatrochemistry, biochemistry, the chemistry of life. He worked in Europe in the 16^th century. The place was Basel in Switzerland. The year was 1527.
• There is an instant in the ascent of man when he steps out of the shadow land of secret and anonymous knowledge into a new system of open and personal discovery. Paracelsus (1493-1541) was the first man to recognize an industrial disease. He was not a quack but a man of divided but profound genius.
• The symbolic year of destiny was 1543 when three books were published that changed the mind of Europe: the anatomical drawings of Andreas Vesalius; the first translation of the Greek mathematics and physics of Archimedes; and The Revolution of the Heavenly Orbs by Nicholas Copernicus, which put the sun at the center of the heaven and created what is now called the Scientific Revolution.
• All that battle between past and future was summarized prophetically in 1527 when Paracelsus threw into the traditional student bonfire an ancient medical textbook by Avicenna.
• That gesture of Paracelsus had said, ‘Science cannot look back to the past. There never was a Golden Age.’ And from the time of Paracelsus 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.
• The odd thing is that the man who made the discovery, Joseph Priestley, was not studying the nature of fire, but another of the Greek elements, the invisible and omnipresent air.
• Most of what remains of Joseph Priestley’s laboratory is in the Smithsonian Institution in Washington, D.C.
• On the second anniversary of the storming of the Bastille, the loyal citizens burned down what Priestly described as one of the most carefully assembled laboratories in the world.
• He went to America but was not made welcome. Only his intellectual equals appreciated him; when Thomas Jefferson became President, he told Joseph Priestley, ‘Yours is one of the few lives precious to mankind.’
• Priestly also discovered that the green plants breathe out oxygen in sunlight, and so make a basis for the animals who breathe it in.
• The ascent of man is made by people who have two qualities: an immense integrity and at least a little genius. Priestley had both.
• The next 100 years were to show this is crucial; the animals would not have evolved at all if the plants had not made oxygen first. But in the 1700s nobody had thought about that.
• It might seem a dizzy hope that we can march from the primitive processes of the first coppersmiths and the magical speculations of the alchemists to the most powerful idea in modern science: the idea of the atoms. Yet the route, the firewalker’s route, is direct.
• One step remains beyond the notion of chemical elements that Lavoisier quantified, to its expression in atomic terms by the son of a Cumberland hand-loom weaver, John Dalton.
• In the chill damp of Manchester, 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 marvelous discovery in chemistry – in those five years ten new elements were found; and yet Dalton was not interested in any of that.
• 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?
• The weighted quantities of different elements that combine with one another express, by their constancy, an underlying scheme of combination between their atoms.
• This is 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 lesson makes a point about scientific method. Dalton was a man of regular habits. For 57 years he walked out of Manchester every day; he measured the rainfall, the temperature – a singularly monotonous enterprise in this climate.
• 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 is the essence of science: ask an impertinent question, and you are on the way to the pertinent answer.