The Dream Pool Essays (or Dream Torrent Essays) was an extensive book written by the Chinese polymath and statesman Shen Kuo (1031–1095), published in 1088 during the Song dynasty (960–1279). Shen compiled this encyclopedic work while living in forced retirement from government office, naming the book after his private estate near modern Zhenjiang, Jiangsu province. The Dream Pool Essays was heavily reorganized in reprint editions by later Chinese authors from the late 11th to 17th centuries. In modern times it has been translated from Chinese into several languages. These include English, German, French, and Japanese translations.
The Dream Pool Essays covers a range of topics including discoveries and advancements in traditional Chinese medicine, mathematics, astronomy, science and technology, optics, architecture and civil engineering, metallurgy, and early archaeology. Observations of the natural world included those of wildlife, meteorology, hypotheses advancing early ideas in geomorphology and climate change based on findings of petrification and natural erosion, and strange recorded phenomena such as the description of an unidentified flying object. In addition to establishing the theory of true north in magnetic declination towards the North Pole,Sivin (1995), III, 22. Shen was also the first to record the use of a compass for navigation,Mohn (2003), 1. the first to describe the invention of movable type printing by contemporary artisan Bi Sheng,Bowman (2000), 105. and the first in China to describe a drydock for repairing boats out of water.Needham (1986), Volume 4, Part 3, 660.
History Shen Kuo was a renowned government official and military general during the Northern Song period of China. However, he was impeached from office by chancellor Cai Que (蔡確; 1036–1093), who wrongly held him responsible for a Song Chinese military defeat by the Tangut-led Western Xia dynasty in 1081 during the Song–Xia wars.Sivin (1995), III, 9. When Shen compiled and published The Dream Pool Essays (Meng Xi Bi Tan, 《梦溪笔谈》) in 1088, he was living in retirement and relative isolation on his lavish garden estate near modern-day Zhenjiang, Jiangsu province. He titled the book after the name he gave to his private estate, the "Dream Brook". In English a full literal translation of the title is Brush Talks from a Dream Brook, and Shen Kuo is quoted as saying:in his biography in the Dictionary of Scientific Biography (New York 1970–1990)
As the historian Chen Dengyuan points out, much of Shen Kuo's written work was probably purged under the leadership of minister Cai Jing (1046–1126).Sivin, III, 44. For example, only six of Shen's books remain, and four of these have been significantly altered since the time they were penned by the author.Sivin, III, 44–45. The Dream Pool Essays was first quoted in a Chinese written work of 1095 AD, showing that even towards the end of Shen's life his final book was becoming widely printed. The book was originally 30 chapters long, yet an unknown Chinese author's edition of 1166 AD edited and reorganized the work into 26 chapters.Sivin, III, 45. There is one surviving copy of this 1166 edition now in Japan, while a Chinese reprint was produced in 1305. In 1631 another edition was printed, but it was heavily reorganized into three broad chapters.
In modern times, Zhang Jiaju's biographical work Shen Kuo (1962) contains selected translations of the Dream Pool Essays from Middle Chinese into modern Vernacular Chinese. The Dream Pool Essays has also been translated from Chinese into various foreign languages. Various volumes of Joseph Needham's Science and Civilization in China series published since 1954 contain a large amount of selected English translations of the Dream Pool Essays. The Brush Talks from Dream Brook is the first complete English translation, presented in two volumes by translators Wang Hong and Zhao Zheng, and published in 2008 by the Sichuan People's Publishing House, China. A Japanese translation of the 1166 Chinese edition was prepared by the History of Science Seminar, Institute for Research in Humanities (Jimbun Kagaku Kenkyusho) for Kyoto University, and printed by the author Umehara Kaoru in his 3-volume edition of Bokei hitsudan (1978–1981).Sivin (1995), III, 49. Quoted excerpts from the Dream Pool Essays in French were printed in the written works of J. Brenier in 1989 and J. F. Billeter in 1993. A complete German translation is offered in Shen Kuo: Pinselunterhaltungen am Traumbach. Das Gesamte Wissen des Alten China, translated and edited by Konrad Herrmann, and published in 1997 by Diederichs Verlag Munich (Gelbe Reihe Magnum, vol. I).
Content The text addressed scientific knowledge in areas including physics, astrology, mathematics, and medicine; it contended that there was no contradiction between technology and Confucian precepts.
Geological theory
With Shen's writings on fossils, geomorphology, and shifting geographical climates, he states in the following passages:
In the Zhi-ping reign period [1064–67 AD] a man of Zezhou was digging a well in his garden, and unearthed something shaped like a squirming serpent, or dragon. He was so frightened by it that he dared not touch it, but after some time, seeing that it did not move, he examined it and found it to be stone. The ignorant country people smashed it, but Zheng Boshun, who was magistrate of Jincheng at the time, got hold of a large piece of it on which scale-like markings were to be seen exactly like those on a living creature. Thus a serpent or some kind of marine snake (chhen) had certainly been turned to stone, as happens with the 'stone-crabs'.Needham, Volume 3, 618.Chan, 15.
In recent years [cca. 1080] there was a landslide on the bank of a large river in Yong-ning Guan near Yanzhou. The bank collapsed, opening a space of several dozens of feet, and under the ground a forest of bamboo shoots was thus revealed. It contained several hundred bamboo with their roots and trunks all complete, and all turned to stone...Now bamboos do not grow in Yanzhou. These were several dozens of feet below the present surface of the ground, and we do not know in what dynasty they could possibly have grown. Perhaps in very ancient times the climate was different so that the place was low, damp, gloomy, and suitable for bamboos. On the Jin-hua Shan in Wuzhou there are stone pine-cones, and stones formed from peach kernels, stone bulrush roots, stone fishes, crabs, and so on, but as these are all (modern) native products of that place, people are not very surprised at them. But these petrified bamboos appeared under the ground so deep, though they are not produced in that place today. This is a very strange thing.Needham, Volume 3, 614.
Astronomy
When the Director of the Astronomical Observatory asked Shen Kuo if the shapes of the Sun and Moon were round like balls or flat like fans, Shen Kuo explained his reasoning for the former:
If they were like balls they would surely obstruct each other when they met. I replied that these celestial bodies were certainly like balls. How do we know this? By the waxing and waning of the moon. The moon itself gives forth no light, but is like a ball of silver; the light is the light of the sun (reflected). When the brightness is first seen, the sun(-light passes almost) alongside, so the side only is illuminated and looks like a crescent. When the sun gradually gets further away, the light shines slanting, and the moon is full, round like a bullet. If half of a sphere is covered with (white) powder and looked at from the side, the covered part will look like a crescent; if looked at from the front, it will appear round. Thus we know that the celestial bodies are spherical.
When the director of the astronomical observatory asked Shen Kuo why eclipses occurred only on an occasional basis while in conjunction and opposition once a day, Shen Kuo wrote:
I answered that the ecliptic and the moon's path are like two rings, lying one over the other, but distant by a small amount. (If this obliquity did not exist), the sun would be eclipsed whenever the two bodies were in conjunction, and the moon would be eclipsed whenever they were exactly in position. But (in fact) though they may occupy the same degree, the two paths are not (always) near (each other), and so naturally the bodies do not (intrude) upon one another.Needham, Volume 3, 415–416.
On the use of the sighting tube to fix the position of the pole star, Shen Kuo wrote:
Before Han times it was believed that the pole star was in the center of the sky, so it was called Jixing (Summit star). Zu Geng(-zhi) found out with the help of the sighting tube that the point in the sky which really does not move was a little more than 1 degree away from the summit star. In the Xining reign-period (1068–1077) I accepted the order of the emperor to take charge of the Bureau of the Calendar. I then tried to find the true pole by means of the tube. On the very first night I noticed that the star which could be seen through the tube moved after a while outside the field of view. I realized, therefore, that the tube was too small, so I increased the size of the tube by stages. After three months' trials I adjusted it so that the star would go round and round within the field of view without disappearing. In this way I found that the pole star was distant from the true pole somewhat more than 3 degrees. We used to make the diagrams of the field, plotting the positions of the star from the time when it entered the field of view, observing after nightfall, at midnight, and early in the morning before dawn. Two hundred of such diagrams showed that the 'pole star' was really a circumpolar star. And this I stated in my detailed report to the emperor.Needham, Volume 3, 262.
Movable type printing
On the methods of Bi Sheng's invention of movable type printing between the years 1041 to 1048 AD, Shen Kuo wrote:
[Bi Sheng] took sticky clay and cut in it characters as thin as the edge of a coin. Each character formed, as it were, a single type. He baked them in the fire to make them hard. He had previously prepared an iron plate and he had covered his plate with a mixture of pine resin, wax, and paper ashes. When he wished to print, he took an iron frame and set it on the iron plate. In this he placed the types, set close together. When the frame was full, the whole made one solid block of type. He then placed it near the fire to warm it. When the paste [at the back] was slightly melted, he took a smooth board and pressed it over the surface, so that the block of type became as even as a whetstone. If one were to print only two or three copies, this method would be neither simple nor easy. But for printing hundreds or thousands of copies, it was marvelously quick. As a rule he kept two forms going. While the impression was being made from the one form, the type was being put in place on the other. When the printing of the one form was finished, the other was then ready. In this way the two forms alternated and the printing was done with great rapidity.Needham, Volume 5, Part 1, 201.
Personal beliefs and philosophy
Of Taoism and the inability of empirical science to explain everything in the world, Shen Kuo wrote: