San Francisco

IT is a cruel and poignant certainty that the children who died in the wreckage of their school during the earthquake this week in Dujiangyan, China, knew all too well that their country once led the world in the knowledge of the planet’s seismicity.

They would have been taught, and proudly, that almost 2,000 years ago an astronomer named Chang Heng invented the world’s first seismoscope. It was a bizarrely imagined creation, with its centerpiece a large bronze vessel surrounded by eight dragons, each holding a sphere in its mouth.

A complex system of internal levers ensured that if an earthquake ever disturbed the vessel, a ball would drop from a dragon’s care into the mouth of a bronze frog positioned underneath. By observing which dragon had dropped its ball, Chang Heng could ascertain the location of the quake. And always, as the emperor for whom Chang Heng fashioned the device noted, the earthquakes came from the mountains in the west, where Dujiangyan lies.

As we watch with mounting melancholy the devastation from Sichuan, a question lingers, and troublingly. Why, if the Chinese had come to know so much about earthquakes so early on in their immensely long history, were they never able to minimize the effects of the world’s contortions — to at least the degree that America has? Why did they leave the West to become leaders in the field, and leave themselves to become mired, time and again, in the kind of tragic events that we are witnessing this week?

The question applies to very much more than the science of earthquakes. In almost every area of technology the Chinese were once supreme, without competition. The stirrup, so hugely important in peace and war, was invented by the Chinese. Printing, gunpowder, the use of the compass — the three inventions that Francis Bacon once said defined the modern world — are all thought to have been first made in China. So too, many think, were vaccination, toilet paper, segmental arch bridges, iron chains and perhaps chess — the list seems endless.

And yet, in the 16th century China’s innovative energies inexplicably withered away, and modern science became the virtual monopoly of the West. There had been any number of Chinese Euclids and Archimedes but there was never to be a Chinese Newton or Galileo. The realm fell steadily behind, century by century; it became impoverished, backward and prey to the caprices of nature.

There is a peculiar paradox in the Sichuan disaster. Dujiangyan is known across the nation as the site of one of China’s greatest ancient wonders. In 256 B.C. an engineer named Li Bing, concerned about the catastrophic annual flooding of the Min River, completed a huge water diversion and irrigation scheme. It involved cutting a long trench through a granite mountainside — achieved by the patient process of burning grass bonfires on top of the rocks and pouring cold water until the granite cracked. It took decades, but Li Bing’s 2,300-year-old project still stands less than a mile from the town’s ruined school, and it still works.

And yet, did the Chinese continue with their early expertise in flood prevention? Just as with Chang Heng’s seismic mastery, Li Bing’s expertise counted for nothing; year upon year, thousands of Chinese die in immense inundations in the great rivers that course across the country; some 400 dams sustained damage in this week’s quake.

Historians have long debated why the Chinese so signally failed to exploit their early promise. Lack of internal competition, some suggest. Others blame the long-held central ambition of every young Chinese man to become a Confucian mandarin, a bureaucrat, rather than an engineer or scientist.

Not a few others, however — admirers of China and optimists in the main — say that in the long sweep of Chinese history, a mere 400 or 500 dark, non-scientific years are a mere blip, a hiccup, and that China’s innovative energies are now roaring back, with the universities and scientific institutions brimming as they did back in the golden ages of the great dynasties.

That had better be the case. China, in its headlong attempts to modernize, has often demonstrated a dismayingly cavalier attitude toward the well-being of its people: skyscrapers are built with little attention to safety standards and are invariably far from earthquake-resistant; huge dams — not least the monstrosity that has so ruined the Three Gorges of the Yangtze — are erected in a slapdash fashion; subways, like the system burrowing through the waterlogged alluvium beneath Shanghai, are built with incautious haste; freeway tunnels are bored through earthquake fault zones.

If the country does not occasionally stand back and pause for breath, then its future — at least so far as nature’s occasional moments of seismic madness are concerned — will continue to be marked by calamity. Until this week Dujiangyan was a place of which China could be proud; today its wreckage stands as a tragic monument to a culture that turned its back on its remarkable and glittering history.