Shen Kuo
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Shen Kuo or Shen Kua (Chinese: 沈括; pinyin: Shěn Kuò) (1031 - 1095) was a Chinese scientist, polymath, general, diplomat, and financial officer of the Song Dynasty. He was the inventor of a compass for navigation, and the first to describe the magnetic needle used for navigation. Kuo also discovered the concept of true north in terms of magnetic declination towards the north pole, with “the improved meridian determined by Shen’s measurement of the distance between the polestar and true north”. [1] This was a decisive step in human history to make compasses more useful for navigation.
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[edit] Life and Works
In his busy life and career as a scholar-official for the central government, Shen Kuo was an ambassador to the Xi-Xia Dynasty (and other countries), a military commander, a director of hydraulic works, and the leading chancellor of the Han-Lin Academy.[2]
In the book Meng Xi Bi Tan (梦溪笔谈; Dream Pool Essays) (1088) Shen Kuo made one of the first references in human history to the magnetic compass, the concept of true north, and its use for navigation.[2] In it, he also wrote about minerology, erosion, sedimentation and uplift, mathematics, astronomy, and metereology. The literal translation of Meng Xi Bi Tan (or Meng ch'i pi t'an) is Brush Talks from Dream Brook. The name derives from his property on the outskirts of Jiangsu (Zhenjiang), a place of great beauty which he named "Dream Brook" and where he lived in isolation for the last seven years of his life. In his biography in the Dictionary of Scientific Biography (New York 1970-1990), Shen Kuo is quoted:
- Because I had only my writing brush and ink slab to converse with, I call it Brush Talks.
He formulated a hypothesis for the process of land formation; based on his observation of fossil shells in a geological stratum in a mountain hundreds of miles from the ocean. He inferred that the land was formed by erosion of the mountains and by deposition of silt. Shen Kuo was not only a geologist; his memoirs list "regularities underlying phenomena" in magnetism, astronomy, and engineering.[2] The historian Joseph Needham outlines Shen's twenty-six chapters of this book, labeled as such:[3]
The Humanities:
- Official life and the imperial court (60 paragraphs)
- Academic and examination matters (10 paragraphs)
- Literary and artistic (70 paragraphs)
- Law and police (11 paragraphs)
- Military (25 paragraphs)
- Miscellaneous stories and anecdotes (72 paragraphs)
- Divination, magic, and folklore (22 paragraphs)
The Natural Sciences:
- On the I Ching, Yin and Yang, and 5 elements (7 paragraphs)
- Mathematics (11 paragraphs)
- Astronomy and calendar (19 paragraphs)
- Meteorology (18 paragraphs)
- Geology and mineralogy (17 paragraphs)
- Geography and cartography (15 paragraphs)
- Physics (6 paragraphs)
- Chemistry (3 paragraphs)
- Engineering, metallurgy, and technology (18 paragraphs)
- Irrigation and hydraulic engineering (6 paragraphs)
- Architecture (6 paragraphs)
- Biological sciences, botany, and zoology (52 paragraphs)
- Agricultural arts (6 paragraphs)
- Medicine and pharmaceutics (23 paragraphs)
The Humanistic Sciences:
- Anthropology (6 paragraphs)
- Archeology (21 paragraphs)
- Philology (36 paragraphs)
- Music (44 paragraphs)
(Total number of paragraphs = 584)[3]
Shen Kuo wrote about the Chinese inventor of movable type, Bi Sheng, and because of his works the legacy of Bi Sheng and the modern understanding of early movable type has been handed down to generations after.
He also wrote about Yi Xing (672-717), a Buddhist monk (who applied an early escapement mechanism to a water-powered celestial globe) and his calculation of possible positions on a go board, but without a sign for zero Yi Xing had difficulties expressing the number.
His work has been compared to that of his equally brilliant contemporary Su Song (engineer of a water-powered astronomical clock tower), who wrote the Ben Cao Tu Jing treatise of 1070 (on botany, zoology, minerology, and pharmaceutical medicine).
[edit] Writing Style
[edit] Formal Writing Style
Most of Shen's work was written in empirical, objective fashion. An example of such would be Shen Kuo describing the use of a drydock to repair boats. He wrote (in Wade-Giles):
| “ | At the beginning of the dynasty (c. +965) the two Che provinces (now Chekiang and southern Chiangsu) presented (to the throne) two dragon ships each more than 200 ft. in length. The upper works included several decks with palatial cabins and saloons, containing thrones and couches all ready for imperial tours of inspection. After many years, their hulls decayed and needed repairs, but the work was impossible as long as they were afloat. So in the Hsi-Ning reign period (+1068 to +1077) a palace official Huang Huai-Hsin suggested a plan. A large basin was excavated at the north end of the Chin-ming Lake capable of containing the dragon ships, and in it heavy crosswise beams were laid down upon a foundation of pillars. Then (a breach was made) so that the basin quickly filled with water, after which the ships were towed in above the beams. The (breach now being closed) the water was pumped out by wheels so that the ships rested quite in the air. When the repairs were complete, the water was let in again, so that the ships were afloat once more (and could leave the dock). Finally the beams and pillars were taken away, and the whole basin covered over with a great roof so as to form a hanger in which the ships could be protected from the elements and avoid the damage caused by undue exposure.[4] | ” |
[edit] Informal Writing Style
Although much of Shen's writing can be typified as formal and with empirical, objective format, there is also writing of his that can be informal, relaxed, opinionated, etc., while posing questions to the reader and appealing both to the layman and the intellectual. For example writing in 1080 AD on the subject of painting in artwork, while criticizing the painting style of one Li Cheng, he wrote (in Wade-Giles spelling):
| “ | ...Then there was Li Chheng, who when he depicted pavilions and lodges amidst mountains, storeyed buildings, pagodas and the like, always used to paint the eaves as seen from below. His idea was that 'one should look upwards from underneath, just as a man standing on level ground and looking up at the eaves of a pagoda can see its rafters and its cantilever eave rafters'. This is all wrong. In general the proper way of painting a landscape is to see the small from the viewpoint of the large (i ta kuan hsiao), just as one looks at artificial mountains in gardens (as one walks about). If one applies (Li's method) to the painting of real mountains, looking up at them from below, one can only see one profile at a time, and not the wealth of their multitudinous slopes and profiles, to say nothing of all that is going on in the valleys and gorges, and in the lanes and courtyards with their dwellings and houses. If we stand to the east of a mountain its western parts would be on the vanishing boundary of far-off distance, and vice-versa. Surely this could not be called a successful painting? Mr. Li did not understand the principle of 'seeing the small from the viewpoint of the large'. He was certainly marvelous at diminishing accurately heights and distances, but should one attach such importance to the angles and corners of buildings? [5] | ” |
[edit] Shen Kuo's dissertation on the Timberwork Manual
Shen Kuo was one to praise the architectural written work of Yu Hao, who once had a marvelous wooden Chinese pagoda built at the Song capital of Kaifeng (as mentioned in the Song Dynasty article, refer to Architecture section). Below is a passage from one of Shen's books outlining the basics contained in Yu's 10th century work on early Song-era architecture (Wade-Giles spelling):
| “ | Methods of building construction are described in the Timberwork Manual, which, some say, was written by Yu Hao. (According to that book), buildings have three basic units of proportion (fen), what is above the cross-beams follows the Upperwork Unit, what is above the ground floor follows the Middlework Unit, and everything below that (platforms, foundations, paving, etc.) follows the Lowerwork Unit. The length of the cross-beams will naturally govern the lengths of the uppermost cross-beams as well as the rafters, etc. Thus for a (main) cross-beam of (8 ft.) length, an uppermost cross-beam of (3.5 ft.) length will be needed. (The proportions are maintained) in larger and smaller halls. This (2/28) is the Upperwork Unit. Similarly, the dimensions of the foundations must match the dimensions of the columns to be used, as also those of the (side-) rafters, etc. For example, a column (11 ft.) high will need a platform (4.5 ft.) high. So also for all the other components, corbelled brackets (kung), projecting rafters (tshui), other rafters (chueh), all have their fixed proportions. All these follow the Middlework Unit (2/24). Now below of ramps (and steps) there are three kinds, steep, easy-going, and intermediate. In places these gradients are based upon a unit derived from the imperial litters. Steep ramps (chun tao) are ramps for ascending which the leading and trailing bearers have to extend their arms fully down and up respectively (ratio 3/35). Easy-going ramps (man tao) are those for which the leaders use elbow length and the trailers shoulder height (ratio 1/38); intermediate ones (phing tao) are negotiated by the leaders with downstretched arms and trailers at shoulder height (ratio 2/18). These are the Lowerwork Units. The book (of Yu Hao) had three chapters. But builders (thu mu chih kung) in recent years have become much more precise and skillful (yen shan) than formerly. Thus for some time past the old Timberwork Manual has fallen out of use. But (unfortunately) there is hardly anybody capable of writing a new one. To do that would be a masterpiece in itself![6] | ” |
[edit] Notes
[edit] References
- Needham, Joseph (1986). Science and Civilization in China: Volume 1. Taipei: Caves Books, Ltd.
- Needham, Joseph (1986). Science and Civilization in China: Volume 4, Part 3. Taipei: Caves Books, Ltd.
- Sivin, Nathan (1995). Science in Ancient China. Brookfield, Vermont: VARIORUM, Ashgate Publishing.
