Lunqi 論氣

Lunqi 論氣 "A Discussion of Substance" is a book on physics written by the late Ming-period 明 (1368-1644) scholar Song Yingxing 宋應星 (1587-c. 1666), who is better known as the author of the technical book Tiangong kaiwu 天工開物.

The Lunqi is composed of four parts called Xing qi hua 形氣化 "Air-ization of shape", Qisheng 氣聲 "Air and sound", Shui fei sheng huo shuo 水非勝火說 "Water does not vanquish fire", and Shui chen 水塵 "Water and dust". It was printed during the Chongzhen reign-oeriod 崇禎 (1629-1644) and was only rediscovered in the Jiangxi Library (Jiangxi Tushuguan 江西省圖書館) and republished in 1976 by the Renmin Press 人民出版社出 in Shanghai in an edition annotated by Qiu Feng 丘鋒.

The text discusses the nature of matter (qi 氣), its transformation, its sounds, and negates the ancient belief that the Agent water vanquishes fire, and instead proposes the theory of water and dust, water and wind, and coldness and heat. In the eyes of Song Yingxing, the ancient belief in the Five Agents or elements (wuxing 五行) was antiquated and had to be replaced by a more suitable concept of one type of matter that has different shapes and aggregate statuses, and that the ten thousand beings are made of this one substance. In his eyes, things that have no shape, were consisting of air (qi 氣), and what was not air, was solid matter. Between these two aggregate states were fire and water. Air became solid matter by transformation, and the latter could again disaggregate into air particles. Voice, sound and wind were also products of the basic substance by an interchange and echo between air and air. Heat and coldness were a result of various shares of these factors in the substance, like seventy parts to thirty parts.