In ancient China there was Sunshu Ao (6th century BC), Ximen Bao (5th century BC), Du Shi (circa 31

AD), Zhang Heng (78 - 139 AD), and Ma Jun (200 - 265 AD), while medieval China had Su Song (1020 - 1101

AD) and Shen Kuo (10311095). Du Shi employed a waterwheel to power the bellows of a blast

furnace producing cast iron. Zhang Heng was the first to employ hydraulics to provide motive power in rotating

an armillary sphere for astronomical observation.