|[Photo from 01ny.cn]|
In AD 31, Nanyang's prefect, Du Shi, invented an air-blower to solve the problem of manpower in smelting iron. Driven by steam trundling a wheel, the blower sends air into an iron-making furnace. It needs less manpower but brings great efficiency. The machine, invented 1,100 years before the European ones, is the first waterpower air-blower in the world.