Mr. Weng Yongni recently wrote an “Interpretation of the Development History of Ancient Irrigation Projects” (see the second volume of the Theses Celebrating Mr. Cai Yuanpei’s 65 Years Old), saying that large-scale artificial irrigation led to the development of agriculture, which seemed to come from the Warring States Period. Based on his geological experience and field investigation, Mr. Weng believes that: “The experience of ancient irrigation engineering first occurred at the foot of Taihang Mountain in the west of the North China Plain. At the beginning, due to the separation of countries and lack of communication, it was not widely spread. Later, due to political reasons, it was accidentally introduced into Guanzhong 关中 (the Weihe River Basin in Shaanxi), so the effect of irrigation projects became more widely known. Because of the strong political power of Qin, it spread outward, southward into Sichuan and westward to Ningxia. After the two unified dynasties of Qin and Han, it spread more widely.