The Needham Question

What do these things have in common? Fireworks, wood-block 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 the Middle Ages, maintained a cultural and technological sophistication that made foreign dignitaries flock to its imperial courts for trade and favour. 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.