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Hello, what are these things having common? Fireworks, woodblock printing, canal lock gates, kites, the wheelbarrow, chain suspension bridges and the magnetic compass.

The answer is that they were all invented in China, a country that right through our Middle Ages maintained a cultural and technological sophistication

that made foreign dignitaries flock to its imperial courts for trade and favor. But then, around 1700, the flow of ingenuity began to dry up, and even reverse as Europe bore the fruits of the scientific revolution back across the globe.

Why did modern science develop in Europe when China seemed so much better place to achieve it? This is called a Needham question, after Joseph Needham, the 20th century British synologist who did more perhaps than anyone else to try and explain it.

But did Joseph Needham give a satisfactory answer to the question that bears his name? Why did China's early technological brilliance not lead to the development of modern science and how did momentous inventions like gunpowder and printing enter Chinese society with value ripple and yet revolutionize the warring states of Europe?

We need to discuss Chinese science and the Needham question, a Tim Barrett, professor of East Asian history at SARS, Francis Wood, head of Chinese Collections of the Bridges Library, and Chris Cullen, director of the Needham Research Institute in Cambridge.

Chris Cullen, at the heart of the Needham question, is a series of brilliant inventions.

Let's start with one that's little known, 4th century, the breast strap harness. Why was that so important?

Well, just imagine I wanted you to help me pull load in my garden. If I gave you a rope and said I'd like you to tie this rope around your neck and then pull hard, you might complain and say, that's not going to be a very good way to get the best effort out of me.

However, in the ancient west, that was how on harnessed horses, you put basically a strap around where the effort was taken from their neck, and that meant the heart of the horse pulled the more it choked itself, which is the reason why you can see in ancient Greek and Roman depictions of chariots.

You might have three or four horses there, but all they can pull is a rather light thing. Whereas in China, they had a much more efficient way of getting traction from the animal.

The breast strap harness, which goes more like round the animal's chest, not on its throat, so that some people have said that a hand in a steed chariot around the beginning of the Christian era is like a bus or a van compared to a western chariot, and that meant the Chinese were able to use horses much more efficiently.

That leads on in China to the invention of the horse collar, which is in China from about, say, the 5th century AD for fattener, about 500 AD, and doesn't arrive in the west until the 10th century AD.

And when it does get to the west, this is a momentous change, because it means that instead of applying with slow, plodding oxen, you can use the much faster horse that can do a field quicker, and also can walk quite easily several miles to the field before you do the work.

So you can plow more, you can have peasants who live together in larger settlements and are more productive. So in Europe, this had an immense transformative effect, and formed the foundation of what some have called a medieval economic revolution in Europe.

And that went on and on, but Francis Bacon, let's start with him, in the early 17th century, said that the modern world, a different fundamental primitive ancient world, because of three key inventions, he said to gunpowder, printing, and the magnetic compass, he thought they, or he said their origins are obscure, and in glorious, we will now know they came from China, let's talk about gunpowder.

Can you talk about how the Chinese invented gunpowder?

Gunpowder is of course one of the first great improvements by the human race in the killing of human beings, and rather ironically it was developed in China by people who are searching for the elixir of life, seeking to find out how they could, as they were to put it, subdue potassium nitrate to make it a medicine you could take.

Unfortunately, in subduing it, they discovered a certain mixture, sometime in around the ninth century, of honey, salt, peeta, and sulfur, that when you cook it up, and the water begins to go out of it, and it starts to turn into a sulfurous toffee, starts to go off like a volcano.

And so the Taoist text in which this is found says basically don't try this at home or you'll burn the house down, send your beard and give Taoism a bad name, but by 1044 AD, you find in a Chinese military manual the first really quite good recipe for gunpowder, before the time of the battle of Hastings.

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