How did the Chinese transport heavy stones from a quarry west of Beijing in the 15th and 16th centuries? According to historical accounts, stones of more than 300 tonnes were moved 70 km on wooden sleds. After many years of speculation on the details, Jiang Li of the University of Science and Technology in Beijing and colleagues have translated a 500-year-old description of such a transportation and performed a detailed analysis of the engineering. They have confirmed that the key was an artificial ice path. Rather than the more common wood-on-wood sliding or the use of rollers, it turns out that water-lubricated-wood-on-ice sliding works perfectly for the job requirements of heavy loads and low speeds.
展开▼
