The Mengqi bitan 夢溪筆談 "Brush discussions of the Dream Creek", modern reading Mengxi bitan, is a large collection of essays of the so-called "brush notes" genre (biji 筆記) written by the Song period 宋 (960-1279) scholar Shen Kua 沈括 (1031－1094). The book is 26 juan "scrolls" long and is enriched by an appendix (Bu bitan 補筆談) of 2 juan (in some editions 3 juan) and a sequel (Xu bitan 續筆談) of 1 juan.
Shen Kua, courtesy name Shen Cunzhong 沈存中, came from Qiantang 錢塘 near modern Hangzhou 杭州, Zhejiang, and was in 1054 appointed assistant magistrate (zhupu 主簿) in Shuyang 沭陽. Nine years later he gradutated in the metropolitan examination and was appointed editorial assistant (bianjiao 編校) in the Institute for the Glorification of Literature (Zhaowenguan 昭文館). Later one he became an academician in the Hanlin Academy (Hanlin xueshi 翰林學士), then probationary State Finance Commissioner (quan sansi shi 權三司使) and finally prefect (zhizhou 知州) of Yanzhou 延州. In 1082, when the Tanguts of the Western Xia empire 西夏 (1038-1227) invaded Yongle 永樂 he was ordered to protect the city wall and was made vice military training commissioner (tuanlian fushi 團練副使) of Junzhou 均州. In later years he occupied the posts of Vice Minister of the Court of Imperial Entertainments (guanglushi shaoqing 光祿寺少卿), magistrate of the Southern Capital (si Nanjing 司南京) and then prefect of Runzhou 潤州 (modern Zhenjiang 鎮江, Jiangsu), where he stayed for the rest of his life. Shi Mu's 視穆 Fangyu shenglan 方輿勝覽 narrates the story of how Shen Kua once dreamt of a small mountain that was covered with flowers like brocade, a place he liked very much. Years later Shen bought a beautiful tract of land near Zhenjiang and when he visited his land he saw that it was just the place he had once dreamt of. He therefore called his estate "Dream Creek" (mengxi 夢溪). In this spot he often received guests from which he learnt a lot of interesting and sometimes miraculous things, and decided to write them down. Shen Kua has written 22 books with a length of 155 juan, but except the Mengqi bitan, only part of the collection Changxing ji 長興集 has survived.
The Mengqi bitan covers a very wide range of themes, from politics and economy to culture, military matters, science and technology, agriculture, astonomy, calendar, physics, mathematics, chemistry, biology, geography, literature, history, archeology, medicine, hydraulic engineering and architecture. The Mengqi bitan is divided into seventeen chapters that talk about stories, disputes, music, the sky, human affairs, state offices, power, literature, the arts, certain skills, objects and tools, supernatural matters, and so on. The Bu bitan is divided into eleven chapters, and the Xu bitan is not divided in chapters. The whole text includes more than 600 different stories, in which Shen Kua provides a very critical analysis to the topics he talks about. The chapters about science and technology that make out a third of the book have since long attracted the interest of Chinese and Western scholars. They include valuable information otherwise not found in this convenient and concise way. Shen Kua describes how the cloth manufacturer Bi Sheng 畢升 invented printing with moveable types made of clay. This is the only literary source for this event. Shen Kua speaks of the dyke constructions by Gao Chao 高超 at the Longmen Pass 龍門 of the Yellow River. He Mentions the system of ready-made construction elements (caifenzhi 材分制) that is mentioned in the architect Yu Hao's 喻皓 book Mujing 木經; a sighting device in ancient crossbows; and a Tangutan method of hardening metals by cooling down.
He explains the military weakness of the Song garrisons in the northwest, and the development of the court ritual over time.
The author himself also contributed to scientific progess. He was, for instance, the first scholar creating a concordance for the solar and the lunar calendar (see calendar), the Solar terms calendar (shier qi li 十二氣曆). He established some theories about the origin of of mountains and the course of rivers as a conclusion of his discovery that fossilized shells could be found hundreds of miles away from the coast. Shen Kua’s merits in the field of mathematics are to be found in his development of a method of infinitesimal calculus that he calls xijishu 隙積術 "method of the interstice-volumes" (otherwise known as duojishu 垛積術), and in his advancement of the method to calculate the cord length and the arc length of a circular segment which he calls huiyuanshu 會圓術 "method to meet the round" (earlier known as gutianshu 弧田術). His suggestions were the base for a further solution of these mathematical problems by the Southern Song period 南宋 (1127-1279) scholar Yang Hui 楊輝 and the Yuan period 元 (1279-1368) scholars Zhu Shijie 朱世杰 and Guo Shoujing 郭守敬.
In the field of physics Shen Kua described mirrors in which various zones were cooled down after casting with different velocities, so that optical interference made the material seemingly partially translucent. He also observed and described mirages and light refraction. Shen describes the resonance of zither cords that could be seen in "dancing" pieces of paper attached to the cords. Concerning magnetism Shen Kua is famous for his mentioning several suspension methods for magnetic needles, like the swimming shape, a needle balanced on a fingertip or an the rim of a bowl, or one that is hang up on a silk thread. Shen Kua is credited with the discovery of the magnetic declination (cipianjiao 磁偏角)
The Mengxi bitan is an early source on petrol and salt in China. The author describes how people collected and used petrol in Yanzhou 延州 (modern Yan'an 延安, Shaanxi) and predicts that it would be of great use in later ages (da xing yu shi 大行於世). In the prefecture of Xinzhou 信州 people boiled down the water of "bitter sources" to obtain chalcanthite (danfan 膽礬, CuSO4). Further processed this material can separate into copper, while the sulfate combined with the metal of the cauldron, especially iron. Very famous is Shen Kua's description of the salt production at the lake of Xiechi 解池 in southwestern Shanxi. He divides cooking salt into the the types powdered salt (moyan 末鹽), grained salt (keyan 顆鹽), well salt (jingyan 井鹽) and cliff salt (yanyan 崖鹽). Salt produced in only very few spots was distributed widely in the empire, for which purpose the state issued salt vouchers (yanchao 鹽鈔), of which one was valid 4,800 copper cash. The Mengxi bitan also includes a description of the crystalline phenomenon taiyin xuanjing 太陰玄精 "mysterious essence of the Great Yin", septarium nodular inclusions in stones.
Shen Kua gives insight into Liu Yan's 劉晏 method to balance grain prices during the Tang period 唐 (618-907). This happened by direct purchase of relatively cheap grain in a near district instead of taking the detour by waiting for the central government to announce local prices. In a similar way the early Song politician Fan Zhongyan 范仲淹 was able to bring disaster relief in regions where harvests had failed. The Mengxi bitan is one of the earliest sources on relics of gold currency from the Zhou period state of Chu 楚 that were found in Shouzhou 壽州. Shen Kua describes them as "small golden cakes" (xiao jin bing 小金餅) with the inscription liu zhu 劉主. This might be an error for the words Ying yuan 郢爰 (Ying was the capital of Chu, and yuan a weight unit).
Shen Kua found out that the method to fertilize fields with mud (yutianfa 淤田法) had, although officially introduced during the Song, already been in use during the Tang and even the Han period, and described the method of gathering water behind a dam. He is also one of the first Chinese authors describing the areas where tea was cultivated and how it was brought to the markets. Except Gao Chao's construction works of the Yellow River Shen Kua also mentions how the canal works at the River Bian 汴 between the capital Kaifeng 開封 (modern Kaifeng, Henan) and the former capital Luoyang 洛陽 (modern Luoyang, Henan) were executed and describes the various dams of the Rivers Luo and Bian. He also mentions an old method of strengthening dams by planting trees that served as "deep water pillars" (huangzhu 滉柱). The Fuchan 複閘 sluices of Zhenzhou 真州 (modern Zizheng 儀徵, Jiangsu) are also described.
Modern Chinese scholar hail Shen Kua as a forerunner of "materialist" thought, particularly for his assumption that all objects of the universe were composed—in different densities—of "breath" (qi 氣) as a kind of matter.
The Bu bitan and Xu bitan are quite likely no original texts written by Shen Kua and were added later, so that different editions have different sizes. The Mengqi bitan in the collectanea Baihai 稗海, Xuejin taoyuan 學津討原, Siku quanshu 四庫全書 and Congshu jicheng 叢書集成初編 has 26+2+1 juan. In the Jindai mishu 津逮秘書 the appendix and the sequel are left out. The Sibu congkan xubian 四部叢刊續編 includes the main text and Zhang Yuanji's 張元濟 text-critical annotation. The version in the Shuoku 說庫 and the Gushu congkan 古書叢刊 is 26 juan long, the Bu bitan 3 juan, and the Xu bitan 1 juan. There are several collectanea that include small selections of the Mengqi bitan, like the Wuyishizhai congchao 無一是齋叢鈔, Shuofu 說郛, Jiu xiaoshuo 舊小說 or Baoyantang miji 寶顏堂秘笈.
In 1957 the Zhonghua shuju 中華書局 published an annotated modern version, the Xin jiaozheng Mengqi bitan 新校正夢溪筆談, a year later the Gudian wenxue press 古典文學出版社 followed suit with Hu Daojing's 胡道靜 Mengqi bitan jiaozheng 夢溪筆談校證. The Beijing wenwu press 北京文物出版社 published in 1975 a Yuan period 元 (1279-1368) print, Yuankan Mengqi bitan 元刊夢溪筆談.
There is a partial German translation by Konrad Herrmann (1997), Pinselunterhaltungen am Traumbach: Das gesamte Wissen des Alten China, München: Diederichs. Some few chapters have been translated into English, while others have been investigated as special topics, like in Dawie Fu ([sic, i.e. Fu Dawei 傅大為] 1999), "On Mengxi Bitan’s world of marginalities and 'south-pointing needles': Fragment translation vs. contextual translation", in: De l'un au multiple: Traductions du Chinois vers les langues europénnes, ed. by Viviane Alleton and Michael Lackner. – Paris: Éditions de la maison des sciences de l’homme. - S. 175-202
Fu Zuohua 傅祚華 (1992). "Mengqi bitan 夢溪筆談", in: Zhongguo da baike quanshu 中國大百科全書, Kuangye 礦冶, p. 474.
Li Xueqin 李學勤, Lü Wenyu 呂文鬰 (1996). Siku da cidian 四庫大辭典, vol. 2, p. 1947. Changchun: Jilin daxue chubanshe.
Zhang Yi 張毅 (1994). "Mengqi bitan 夢溪筆談", in: Zhongguo xueshu mingzhu tiyao 中國學術名著提要, Jingji 經濟, p. 166.
Zhou Hanguang 周瀚光 (1996). "Mengqi bitan 夢溪筆談", in: Zhongguo xueshu mingzhu tiyao 中國學術名著提要, Keji 科技, p. 859. Shanghai: Fudan daxue chubanshe.
1. 故事 Gushi Stories
2. 辯證 Bianzheng Discussions
3. 樂律 Yuelü Music
4. 象數 Xiangshu Astronomy and mathematics
5. 人事 Renshi Personalities
6. 官政 Guanzheng Administration
7. 權智 Quanzhi Scholars and inventors
8. 藝文 Yiwen Literature
9. 書畫 Shuhua Calligraphy and painting
10. 技藝 Jiyi Crafts
11. 器用 Qiyong Tools and implements
12. 神奇 Shenqi Supernatural matters
13. 異事 Yishi Strange affairs
14. 謬誤 Miuwu Errors and misbeliefs
15. 譏謔 Jinüe Satire and jokes
16. 雜誌 Zazhi Miscellanea
17. 藥議 Yaoyi Medicine
1. 辯證 Bianzheng Discussions
2. 樂律 Yuelü Music
3. 象數 Xiangshu Astronomy and mathematics
4. 官政 Guanzheng Administration
5. 權智 Quanzhi Scholars and inventors
6. 藝文 Yiwen Literature
7. 器用 Qiyong Tools and implements
8. 雜誌 Zazhi Miscellanea
9. 藥議 Yaoyi Medicine
續筆談 Xu bitan