New Scientist
Image: namealus
Fifteenth-century Chinese engineers didn’t so much reinvent the wheel as dispense with it altogether – opting to drag heavy stones for building the Forbidden City along a slippery artificial ice road instead of wheeling them.
That, at least, is the upshot of the latest analysis of a 17th-century Chinese text. Such a method would be 10 times as efficient as dragging the rocks along non-icy ground – suggesting that Chinese engineers had a more sophisticated understanding of friction than their Western counterparts at that time.
The Forbidden City, in what is now Beijing, housed China’s emperors for almost 500 years. Several of the massive stones incorporated into its design were extracted from the Dashiwo quarry. That is 70 kilometres away – and the stones weigh in excess of 100 tonnes.
Previous attempts to explain how such heavy stones made the long journey assumed sturdy wheeled vehicles were used. This is partly because large wheeled vehicles have been used in China for 2000 years, and partly because there are no images from China of colossal stones being dragged along the ground by teams of men. However, this was somewhat puzzling as even the biggest wheeled vehicles of the time could support no more than 95 tonnes. Read more on newscientist.com…
