the 1st century onwards, chain pumps were widespread throughout the Chinese countryside. Chinese square-pallet chain pumps were used mostly for irrigation, though they found use in public works as well. The infamous Eastern Han court eunuch Zhang Rang (d. A.D. 189) once ordered the engineer Bi Lan (畢嵐) to construct a series of square-pallet chain pumps outside the capital city Luoyang. These chain pumps serviced the palaces and living quarters of the Luoyang; the water lifted by the chain pumps was brought in by a pipe system. Ma Jun, the renowned mechanical engineer of the Three Kingdoms era, also constructed a series of chain pumps for watering the palatial gardens of Emperor Ming of Wei (226–239). During the period of agricultural expansion in Song China (10th-13th centuries CE), the technology of water-rising devices was improved. For some centuries they had been used for moving water for drainage or irrigation purposes. The simplest design, known as the counterbalanced bucket or 'swape' or 'well-sweep' was in common use at that time. A more complicated design, the 'square-pallet chain pump', was introduced several centuries before the growth in Song technology, but had not seen prior use for farming. They became more common around the end of the first millennium AD. From the 13th century onwards, the Chinese also used windmills (acquired from the Middle East) to power square-pallet chain pumps. Yet there were other types of chain pumps besides the square-pallet design. In Song Yingxing's (1587–1666) encyclopedic book the Tiangong Kaiwu (1637), there is description and illustration of a cylinder chain pump, powered by waterwheels and leading water up from the river to an elevated plain of agricultural crops. The contribution of chain pumps to agricultural growth during the Song was extolled by poets such as Li Chuquan (李处权) of the twelfth century. The Song government actively spread the technology, introducing pumping equipment and chain pumps to those areas as yet unfamiliar with the technique. See also Airlift pump Chain drive Rope pump Sakia Waterladder pump Notes References Needham, Joseph (1986). Science and Civilization in China: Volume 4, Physics and Physical Technology, Part 2, Mechanical Engineering. Taipei: Caves Books, Ltd. Needham, Joseph (1986). Science and Civilization in China: Volume 6, Biology and Biological Technology, Part 2, Agriculture. Taipei: Caves Books Ltd. Song, Yingxing, translated with preface by E-Tu Zen Sun and Shiou-Chuan Sun (1966). T'ien-Kung K'ai-Wu: Chinese Technology in the Seventeenth Century. University