page_title: Science and technology of the Han dynasty
section_title: Uses of the waterwheel and water clock
hierarchical_section_title: Science and technology of the Han dynasty / Mechanical and hydraulic engineering / Uses of the waterwheel and water clock
caption_attribution_description: English: Two illustrations of Chinese hydraulic-powered chain pumps. The top illustration shows a horizontal waterwheel acting upon a horizontal and vertical wheel and axle that rotates a square-pallet chain pump bringing water from a stream up to the irrigation canal. The bottom illustration shows a vertical waterwheel as part of a cylinder-wheel chain pump bringing water up from a river to an irrigation canal of a crop field. These illustrations were printed in the Tiangong Kaiwu encyclopedia of 1637, written by the Ming Dynasty encyclopedist Song Yingxing (1587-1666). They can be found on pages 15 and 18 of E-tu Zen Sun and Shiou-Chuan Sun's English translation of the Tiangong Kaiwu (Pennsylvania University State Press, 1966). This image was taken from http://www.chinawater.net.cn/kjcg/CWSArticle_View.asp?CWSNewsID=17233
context_page_description: The Han dynasty of ancient China, divided between the eras of Western Han, Xin dynasty of Wang Mang, and Eastern Han, witnessed some of the most significant advancements in premodern Chinese science and technology.
  There were great innovations in metallurgy. In addition to Zhou-era China's previous inventions of the blast furnace and cupola furnace to make pig iron and cast iron, respectively, the Han period saw the development of steel and wrought iron by use of the finery forge and puddling process. With the drilling of deep boreholes into the earth, the Chinese used not only derricks to lift brine up to the surface to be boiled into salt, but also set up bamboo-crafted pipeline transport systems which brought natural gas as fuel to the furnaces. Smelting techniques were enhanced with inventions such as the waterwheel-powered bellows; the resulting widespread distribution of iron tools facilitated the growth of agriculture.
context_section_description: By the Han dynasty, the Chinese developed various uses for the waterwheel. An improvement of the simple lever-and-fulcrum tilt hammer device operated by one's foot, the hydraulic-powered trip hammer used for pounding, decorticating, and polishing grain was first mentioned in the Han dictionary Jijiupian of 40 BCE. It was also mentioned in the Regional Speech (Fangyan) dictionary written by Yang Xiong (53 BCE – 18 CE) in 15 BCE, the philosophical Xinlun 新論 written by Huan Tan (43 BCE – 28 CE) in 20 CE, the poetry of Ma Rong (79–166 CE), and the writings of Kong Rong (153–208 CE).
  In his Balanced Discourse (Lunheng), the philosopher Wang Chong (27–100 CE) was the first in China to describe the square-pallet chain pump used to lift water (and other substances). Although some models were operated manually by foot pedals, some chain pumps were powered by a horizontal waterwheel which rotated large toothed gears and a horizontal axis beam. Their primary use was for lifting water into irrigation ditches, but chain pumps were also used in public works programs, such as when Zhang Rang (d. 189) had an engineer build several of them to lift water into pipes that provided the capital Luoyang and its palaces with clean water.
  While acting as administrator of Nanyang in 31 CE, Du Shi (d. 38) invented a water-powered reciprocator which worked the bellows of the blast furnace and cupola furnace in smelting iron; before this invention, intensive manual labor was required to work the bellows.
  Although the astronomical armillary sphere (representing the celestial sphere) had existed in China since the 1st century BCE, the mathematician and court astronomer Zhang Heng (78–139 CE) provided it with motive power by using the constant pressure head of an inflow water clock to rotate a waterwheel that acted on a set of gears. Zhang Heng was also the first to address the problem of the falling pressure head in the inflow water clock (which gradually slowed the timekeeping) by setting up an additional tank between the reservoir and inflow vessel.
caption: Two types of hydraulic-powered chain pumps from an encyclopedia written in 1637 by Song Yingxing
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