Du Shi

An illustration of blast furnace bellows operated by waterwheels, from the Nong Shu, by Wang Zhen, 1313 AD, during the Yuan dynasty of China.

Du Shi (, d. 38 ) was a Chinese hydrologist, inventor, mechanical engineer, metallurgist, and politician of the Eastern Han dynasty. Du Shi is credited with being the first to apply hydraulic power (i.e. a waterwheel) to operate bellows (air-blowing device) in metallurgy. His invention was used to operate piston-bellows of the blast furnace and then cupola furnace in order to forge cast iron, which had been known in China since the 6th century BC. He worked as a censorial officer and administrator of several places during the reign of Emperor Guangwu of Han. He also led a brief military campaign in which he eliminated a small bandit army under Yang Yi (d. 26).

Life Early career Although the year of his birth is uncertain, it is known that Du Shi was born in Henei, Henan province. Guangwu was not displeased with this, as he called him into his court to grant him an insignia which justified his actions. When word of the arrival of Du Shi's forces in the region reached Yang Yi, he planned to flee across the Yellow River. Afterwards, Du distinguished himself as a Commandant in Pei and in Runan. In 31 he was appointed as an administrator over Nanyang.

Donald B. Wagner writes that there is no remaining physical evidence of the bellows which Du Shi used, so modern scholars are still unable to determine whether or not they were made of leather or giant wooden fans as described later in the 14th century.

Spread of Use Another Chinese application of a horizontal waterwheel for use in a grain mill, as seen in this Northern Song era (960–1127 AD) painting of an urban river scene. The historical text Sanguo Zhi (Records of the Three Kingdoms) records the use of both human labor and horse-power to operate metallurgic bellows of a blast furnace before water-power was applied. Two decades after this, it is recorded that another design for water-powered bellows was created by Du Yu (222–285). The 5th-century text Shui Jing Zhu mentions the use of rushing river water to power waterwheels, as does the Tang dynasty (618–907) geography text of the Yuanhe Jun Xian Tu Chi, written in 814 AD.

Although Du Shi is the first historical figure to apply water power to metallurgic bellows, the oldest extant Chinese illustration depicting such a device in operation can be seen in a picture of the Nong Shu, printed by 1313 AD during the Yuan dynasty (1271–1368) of China. The text was written by Wang Zhen, who explained the methods used for a water-powered blast-furnace (Wade-Giles spelling):