Zigong Salt History Museum

Address : No .107 Jiefang Road, Zigong, Sichuan, China
The Zigong Salt History Museum is situated in Zigong City, Sichuan Province, in buildings constructed by the salt merchants of Shaanxi. Its buildings utilize China's traditional architectural methods : an 86-meter-long central axis comprises the central hall, with the subsidiary group of buildings going up the slope of a hillside.
The exhibitions of this museum begin with an illustration from a Han Dynasty brick that was excavated in Sichuan. The illustrations on the brick depict the salt industry of the Han period and show in a lively and realistic manner the stages of salt production. Wide-mouthed shallow wells were used for early production a two-story building and four men on the brick show how briny water was brought by conduits to heating units cooked out the water resulted in pure salt.
By the time of the Song dynasty, Chinese craftsmen had invented special tools for digging small-mouth-diameter wells. Not only was the mouth of the well sometimes "as small as a small bowl" but it was dug down very straight into the earth. The tools for allowing this well-tunneling method are recorded in the "Dongpo Forest of Stelae," also exhibited at the Museum.
By the time of the transition period between Ming and Qing dynasties, the depth of these so-called Zhuotong wells reached three hundred Zhang, a Zhang is 3 and 1/3 meters, or around 1, 000 meters. This museum has in its collections a relatively complete set of well-digging tools, that not only could dig deeply but ensured that the well's cavity would be straight. Some modern-day well-digging technologies are a result and a continuation of this historical foundation.
Joseph Needham (1900-1995, Englishman, a world-famous historian of science and technology) listed more than twenty important inventions that had entered Europe from China in his History of Science and Technology in China. The fifteenth of these was the deep-well drilling technology. It is on display and well worth seeing in this unusual museum.