Hidden Buffer

Trade history

The Silk Road was never a single road, nor was silk its only cargo. It was a shifting web of caravan tracks and sea lanes that linked the markets of China to Persia, India, Arabia and the Mediterranean for nearly two thousand years. Paper, gunpowder, printing, sugar and the numeral zero travelled along it, and so did religions, plagues and rumours. Merchants rarely walked the whole distance. Goods passed hand to hand across deserts and mountain passes, each trader adding a margin, so that a bolt of cloth leaving Chang'an might reach Rome at a hundred times its original price.

History of technology

Around 1440 a goldsmith in Mainz named Johannes Gutenberg combined three ordinary things into something extraordinary: movable metal type, oil based ink, and a screw press of the kind used to crush grapes. Before him, a book was copied by hand over months. After him, a workshop could print hundreds of identical copies in a week. Within fifty years Europe held millions of printed books, and ideas that once died in a single monastery library could no longer be contained. Gutenberg himself lost his press to creditors and died with little money, never knowing what he had begun.

Ancient civilisations

Four and a half thousand years ago, the cities of Harappa and Mohenjo daro stood on the plains of the Indus with baked brick houses, covered drains, public wells and streets laid out on a grid. Their people used standardised weights, traded with Mesopotamia, and left behind thousands of small carved seals showing bulls, unicorns and a script of about four hundred signs. That script has never been deciphered. We can measure their bricks and admire their plumbing, yet we still cannot read a single sentence they wrote about themselves.

Twentieth century

The computer that guided Apollo 11 to the lunar surface had less memory than a modern greeting card that plays a tune. When Neil Armstrong took manual control in the final seconds, the machine was flashing alarms because it had been given more work than it could finish. Mission control in Houston recognised the error codes, judged them harmless, and said go. The landing had about twenty five seconds of fuel remaining. Six hundred million people, roughly a fifth of humanity, listened as a man described the powdery grey dust beneath his boots.

Ancient engineering

The Great Wall is not one wall but many, built, abandoned and rebuilt across two thousand years by rival dynasties with different enemies in mind. Much of what tourists photograph today is Ming work of the fifteenth and sixteenth centuries, faced in stone and brick, while earlier stretches were rammed earth that has weathered back into the hills. It was never a sealed barrier. Its real function was to slow raiders, funnel them towards guarded gates, and carry signals of smoke and fire faster than a horse could gallop.