Shen Kuo
From Wikipedia, the free encyclopedia
| Shen Kuo 沈括 |
|
 Shen Kuo, a Chinese scientist famous for his concepts of true north and land formation, among others.
|
|
| Born | 1031 Qiantang |
|---|---|
| Died | 1095 Runzhou |
| Residence | Hangzhou, Xiamen, Kaifeng, Zhenjiang |
| Fields | Geology, Astronomy, Archaeology, Mathematics, Pharmacology, Magnetics, Optics, Hydraulics, Metaphysics, Meteorology, Climatology, Geography, Cartography, Botany, Zoology, Architecture, Agriculture, Economics, Military strategy, Ethnography, Music, Divination |
| Institutions | Hanlin Academy |
| Known for | Geomorphology, Climate change, Paleoclimatology, Atmospheric refraction, True north, Retrogradation, Camera obscura, Raised-relief map, fixing the position of the pole star, correcting lunar and solar errors |
| Religious stance | Daoism, Buddhism, Chinese folk religion |
- This is a Chinese name; the family name is Shen.
Shen Kuo or Shen Kua (Chinese: 沈括; pinyin: Shěn Kuò; Wade-Giles: Shen K'uo) (1031–1095), style name Cunzhong and pseudonym Mengqi (now usually given as Mengxi) Weng,[1] was a polymathic Chinese scientist and statesman of the Song Dynasty (960–1279). Excelling in many fields of study and statecraft, he was a mathematician, astronomer, meteorologist, geologist, zoologist, botanist, pharmacologist, agronomist, archaeologist, ethnographer, cartographer, encyclopedist, general, diplomat, hydraulic engineer, inventor, academy chancellor, finance minister, governmental state inspector, poet, and musician. He was the head official for the Bureau of Astronomy in the Song court, as well as an Assistant Minister of Imperial Hospitality.[2] At court his political allegiance was to the Reformist faction known as the New Policies Group, headed by Chancellor Wang Anshi (1021–1086).
In his Dream Pool Essays (夢溪筆談; Mengxi Bitan) of 1088, Shen was the first to describe the magnetic needle compass, which would be used for navigation (first described in Europe by Alexander Neckam in 1187).[3][4] Shen discovered the concept of true north in terms of magnetic declination towards the north pole,[4] with experimentation of suspended magnetic needles and "the improved meridian determined by Shen’s [astronomical] measurement of the distance between the polestar and true north".[5] This was the decisive step in human history to make compasses more useful for navigation, and may have been a concept unknown in Europe for another four hundred years (evidence of German sundials made circa 1450 show markings similar to Chinese geomancer compasses in regards to declination).[6][7]
Alongside his colleague Wei Pu, Shen accurately mapped the orbital paths of the moon and the planets, in an intensive five-year project that rivaled the later work of the Danish astronomer Tycho Brahe (1546–1601).[8] To aid his work in astronomy, Shen Kuo made improved designs of the armillary sphere, gnomon, sighting tube, and invented a new type of inflow water clock. Shen Kuo devised a geological hypothesis for land formation (geomorphology), based upon findings of inland marine fossils, knowledge of soil erosion, and the deposition of silt.[9] He also proposed a hypothesis of gradual climate change, after observing ancient petrified bamboos that were preserved underground in a dry northern habitat that would not support bamboo growth in his time. He was the first literary figure in China to mention the use of the drydock to repair boats suspended out of water, and also wrote of the effectiveness of the relatively new invention of the canal pound lock. Although Ibn al-Haytham (965–1039) was the first to describe camera obscura, Shen was the first in China to do so, several decades later. Shen wrote extensively about movable type printing invented by Bi Sheng (990–1051), and because of his written works the legacy of Bi Sheng and the modern understanding of the earliest movable type has been handed down to later generations.[10] Following an old tradition in China, Shen created a raised-relief map while inspecting borderlands. His description of an ancient crossbow mechanism which he himself unearthed proved to be a Jacob's staff, a surveying tool which wasn't known in Europe until described by Levi ben Gerson in 1321.
Shen Kuo wrote several other books besides the Dream Pool Essays, yet much of the writing in his other books has not survived. Some of Shen's poetry was preserved in posthumous written works. Although much of his focus was on technical and scientific issues, he had an interest in divination and the supernatural, the latter including his vivid description of unidentified flying objects from eyewitness testimony. He also wrote commentary on ancient Daoist and Confucian texts.
Contents |
[edit] Life
[edit] Birth and youth
Shen Kuo was born in Qiantang (modern-day Hangzhou) in the year 1031. His father Shen Zhou (沈周; 978–1052) was a somewhat lower-class gentry figure serving in official posts on the provincial level; his mother was from a family of equal status in Suzhou, with her maiden name being Xu (許).[11] Shen Kuo received his initial childhood education from his mother, which was a common practice in China during this period.[11]a[›] She was very educated herself, teaching Kuo and his brother Pi (披) the military doctrines of her own elder brother Xu Tang (許洞; 975–1016).[11] Since Shen was unable to boast of a prominent familial clan history like many of his elite peers born in the north, he was forced to rely on his wit and stern determination to achieve in his studies to enter the challenging and sophisticated life of an exam-drafted state bureaucrat.[11]
From about 1040, Shen's family moved around Sichuan province and finally to the international seaport at Xiamen, where Shen's father accepted minor provincial posts in each new location.[12] Shen Zhou also served several years in the prestigious capital judiciary, the equivalent of a federal supreme court.[11] Shen Kuo took notice of the various towns and rural features of China as his family traveled, while he became interested during his youth in the diverse topography of the land.[12] He also observed the intriguing aspects of his father's engagement in administrative governance and the managerial problems involved; these experiences had a deep impact on him as he later became a government official.[12] Since he often became ill as a child, Shen Kuo also developed a natural curiosity about medicine and pharmaceutics.[12]
Shen Zhou died in the late winter of 1051 (or early 1052), when his son Shen Kuo was 21 years old. Shen Kuo grieved for his father, and following Confucian ethics, remained inactive in a state of mourning for three years until 1054 (or early 1055).[13] As of 1054, Shen began serving in minor local governmental posts. However, his natural abilities to plan, organize, and design were proven early in life; one example is his design and supervision of the hydraulic drainage of an embankment system, which converted some one hundred thousand acres (400 km²) of swampland into prime farmland.[13] Shen Kuo noted that the success of the silt fertilization method relied upon the effective operation of sluice gates of irrigation canals.[14]
[edit] Official career
In 1063 Shen Kuo successfully passed the Imperial examinations, the difficult national-level standard test that every high official was required to pass in order to enter the governmental system.[13] He not only passed the exam, however, but placed into the higher category of the best and brightest students.[13] While serving at Yangzhou, Shen's brilliance and dutiful character caught the attention of Zhang Chu (張蒭; 1015–1080), the Fiscal Intendant of the region. Shen made a lasting impression upon Zhang, who recommended Shen for a court appointment in the financial administration of the central court.[13] Shen would also eventually marry Zhang's daughter, who became his second wife.
In his career as a scholar-official for the central government, Shen Kuo was also an ambassador to the Western Xia Dynasty and Liao Dynasty,[15] a military commander, a director of hydraulic works, and the leading chancellor of the Hanlin Academy.[16] By 1072, Shen was appointed as the head official of the Bureau of Astronomy.[13] With his leadership position in the bureau, Shen was responsible for projects in improving calendrical science,[10] and proposed many reforms to the Chinese calendar alongside the work of his colleague Wei Pu.[8] With his impressive skills and aptitude for matters of economy and finance, Shen was appointed as the Finance Commissioner at the central court.[17]
As written by Li Zhiyi, a man married to Hu Wenrou (granddaughter of Hu Su, a famous minister of the Song Dynasty), Shen Kuo was Li's mentor while Shen served as an official.[18] According to Li's epitaph for his wife, Shen would sometimes relay questions via Li to Hu when he needed clarification for his mathematical work, as Hu Wenrou was esteemed by Shen as a remarkable female mathematician.[18] Shen lamented: "if only she were a man, Wenrou would be my friend."[18]
While employed by the central government, Shen Kuo was also sent out with others to inspect the granary system of the empire, investigating problems of illegal collections, negligence, ineffective disaster relief, and inadequate water-conservancy projects.[19] While Shen was appointed as the regional inspector of Zhejiang in 1073, the Emperor requested that Shen pay a visit to the famous poet Su Shi (1037–1101), then an administrator in Hangzhou.[20] Shen took advantage of this meeting to copy some of Su's poetry, which he presented to the Emperor indicating that it expressed "abusive and hateful" speech against the Song court; these poems were later politicized by Li Ding and Shu Dan in order to level a court case against Su.[20] With his demonstrations of loyalty and ability, Shen Kuo was awarded the honorary title of a State Foundation Viscount by Emperor Shenzong of Song (r. 1067–1085), who placed a great amount of trust in Shen Kuo.[17] He was even made 'companion to the heir apparent' (太子中允; 'Taizi zhongyun').[1]
At court Shen was a political favorite of the Chancellor Wang Anshi (1021–1086), who was the leader of the political faction of Reformers, also known as the New Policies Group (新法, Xin Fa).[21]b[›] Shen Kuo had a previous history with Wang Anshi, since it was Wang who had composed the funerary epitaph for Shen's father, Zhou.[22] Shen Kuo soon impressed Wang Anshi with his skills and abilities as an administrator and government agent. In 1072, Shen was sent to supervise Wang's program of surveying the building of silt deposits in the Bian Canal outside the capital city. Using an original technique, Shen successfully dredged the canal and demonstrated the formidable value of the silt gathered as a fertilizer.[22] He gained further reputation at court once he was dispatched as an envoy to the Khitan Liao Dynasty in the summer of 1075.[22] The Khitans had made several aggressive negotiations of pushing their borders south, while manipulating several incompetent Chinese ambassadors who conceded to the Liao Kingdom's demands.[22] In a brilliant display of diplomacy, Shen Kuo came to the camp of the Khitan monarch at Mt. Yongan (near modern Pingquan, Hebei), armed with copies of previously archived diplomatic negotiations between the Song and Liao dynasties.[22] Shen Kuo refuted Emperor Daozong's bluffs point for point, while the Song reestablished their rightful border line.[22] In regards to the Lý Dynasty of Đại Việt (in modern northern Vietnam), Shen demonstrated in his Dream Pool Essays that he was familiar with the key players (on the Vietnamese side) in the prelude to the Sino-Vietnamese War of 1075–1077.[23] With his reputable achievements, Shen became a trusted member of Wang Anshi's elite circle of eighteen unofficial core political loyalists to the New Policies Group.[22]
Although much of Wang Anshi's reforms outlined in the New Policies centered around state finance, land tax reform, and the Imperial examinations, there were also military concerns. This included policies of raising militias to lessen the expense of upholding a million soldiers,[24] putting government monopolies on saltpetre and sulphur production and distribution in 1076 (to ensure that gunpowder solutions would not fall into the hands of enemies),[25][26] and aggressive military policy towards China's northern rivals of the Western Xia and Liao dynasties.[27] A few years after Song Dynasty military forces had made victorious territorial gains against the Tanguts of the Western Xia, in 1080 Shen Kuo was entrusted as a military officer in defense of Yanzhou (modern-day Yan'an, Shaanxi province).[28] During the autumn months of 1081, Shen was successful in defending Song Dynasty territory while capturing several fortified towns of the Western Xia.[17] The Emperor Shenzong of Song rewarded Shen with numerous titles for his merit in these battles, and in the sixteen months of Shen's military campaign, he received 273 letters from the Emperor.[17] However, Emperor Shenzong trusted an arrogant military officer who disobeyed the emperor and Shen's proposal for strategic fortifications, instead fortifying what Shen considered useless strategic locations. Furthermore, this officer expelled Shen from his commanding post at the main citadel, so as to deny him any glory in chance of victory.[17] The result of this was nearly catastrophic, as the forces of the arrogant officer were decimated;[17] Xinzhong Yao states that the death toll was 60,000.[1] Nonetheless, Shen was successful in defending his fortifications and the only possible Tangut invasion-route to Yanzhou.[17]
[edit] Impeachment and later life
The new Chancellor Cai Que (蔡確; 1036–1093) held Shen responsible for the disaster and loss of life.[17] Along with abandoning the territory which Shen Kuo had fought for, Cai ousted Shen from his seat of office.[17] Shen's life was now forever changed, as he lost his once reputable career in state governance and the military.[17] Shen was then put under probation in a fixed residence for the next six years. However, as he was isolated from governance, he decided to pick up the quill and dedicate himself to intensive scholarly studies. After completing two geographical atlases for a state-sponsored program, Shen was rewarded by having his sentence of probation lifted, allowing him to live in a place of his choice.[17] Shen was also pardoned by the court for any previous faults or crimes that were claimed against him.[17]
In his more idle years removed from court affairs, Shen Kuo enjoyed pastimes of the Chinese gentry and literati that would indicate his intellectual level and cultural taste to others.[30] As described in his Dream Pool Essays, Shen Kuo enjoyed the company of the "nine guests" (jiuke), a figure of speech for the Chinese zither, Chinese chess, Zen Buddhist meditation, ink (calligraphy and painting), tea drinking, alchemy, chanting poetry, conversation, and drinking wine.[29] These nine activities were an extension to the older so-called Four Arts of the Chinese Scholar.
According to Zhu Yu's book Pingzhou Table Talks (萍洲可談; Pingzhou Ketan) of 1119, Shen Kuo had two marriages; the second wife was the daughter of Zhang Chu (張蒭), who came from Huainan. Lady Zhang was said to be overbearing and fierce, often abusive to Shen Kuo, even attempting at one time to pull off his beard. Shen Kuo's children were often upset over this, and prostrated themselves to Lady Zhang to quit this behavior. Despite this, Lady Zhang went as far as to drive out Shen Kuo's son from his first marriage, expelling him from the household. However, after Lady Zhang died, Shen Kuo fell into a deep depression and even attempted to jump into the Yangtze River to drown himself. Although this suicide attempt failed, he would die a year later.[31]
In the 1070s, Shen had purchased a lavish garden estate on the outskirts of modern-day Zhenjiang, Jiangsu province, a place of great beauty which he named "Dream Brook" ("Mengxi") after he visited it for the first time in 1086.[17] Shen Kuo permanently moved to the Dream Brook Estate in 1088, and in that same year he completed his life's written work of the Dream Pool Essays, naming the book after his garden-estate property. This book was Shen's ultimate attempt to comprehend and describe a multitude of various aspects of nature, science, and reality, and all the practical and profound curiosities found in the world. The literal translation of Mengxi Bitan is Dream Brook Brush Talks. For this, Shen Kuo is quoted as saying: "Because I had only my writing brush and ink slab to converse with, I call it Brush Talks."c[›] It was there at his peaceful garden estate that Shen Kuo spent the last several years of his life in leisure, isolation, and illness, until his death in 1095.[17]
[edit] Scholarly achievements
Shen Kuo wrote extensively on a wide range of different subjects. His written work included two geographical atlases, a treatise on music with mathematical harmonics, governmental administration, mathematical astronomy, astronomical instruments, martial defensive tactics and fortifications, painting, tea, medicine, and much poetry.[32] While visiting the iron producing district at Cizhou in 1075, Shen described the "partial decarborization" method of reforging cast iron under a cold blast, which Hartwell, Needham, and Wertime state is the predecessor of the Bessemer process.[33] Shen believed that trees were becoming scarce due to the needs of the iron industry and ink makers using pine soot in the production process, so he suggested for the latter an alternative of petroleum, which he believed was "produced inexhaustibly within the earth".[34][35]g[›] Shen used the soot from the smoke of burned petroleum fuel (shi you or "rock oil" as Shen called it) to invent a new, more durable type of writing ink; the Ming Dynasty pharmacologist Li Shizhen (1518–1593) wrote that Shen's ink was "lustrous like lacquer, and superior to that made from pinewood lamp-black," or the soot from pinewood.[36][37] Shen Kuo described the phenomena of natural predator insects controlling the population of pests, the latter of which had the potential to wreak havoc upon the agricultural base of China.[38] Shen Kuo's scientific writings have received worldwide acclaim by many sinologists such as Joseph Needham and Nathan Sivin. His work has often been compared to that of his equally brilliant Chinese contemporary Su Song (1020–1101), the mechanical genius whose astronomical clock tower incorporated a waterwheel, clepsydra, escapement mechanism, and chain drive to operate the armillary sphere, opening doors, and rotating mannequins beating drums, bells, and holding announcement plaques. Shen Kuo has also been compared to many Western intellectual achievers and polymaths, such as Gottfried Leibniz and Mikhail Lomonosov.[39]
[edit] Raised-relief map
- Further information: History of cartography#China
If the account of Sima Qian (c. 145–86 BC) in his Records of the Grand Historian is proven correct upon the unearthing of Qin Shi Huang's (r. 221–210 BC) tomb, the raised-relief map has existed since the Qin Dynasty (221–206 BC).[41] Robert Temple and Joseph Needham suggest that certain pottery vessels of the Han Dynasty (202 BC – 220 AD) showing artificial mountains as lid decorations may have influenced the raised-relief map.[42] The Han Dynasty general Ma Yuan (14 BC – 49 AD) made a raised-relief map of valleys and mountains in a rice-constructed model of 32 AD.[41][43] Such rice models were expounded on by the Tang Dynasty (618–907) author Jiang Fang in his Essay on the Art of Constructing Mountains with Rice (c. 845 AD).[41] A raised-relief map made of wood representing all the provinces of the empire and put together like a giant 0.93 m2 (10 ft2) jigsaw puzzle was invented by Xie Zhuang (421–466 AD) during the Liu Song Dynasty (420–479).[41]
Shen's largest atlas included twenty three maps of China and foreign regions that were drawn at a uniform scale of 1:900,000.[5] Shen also created a three dimensional raised-relief map using sawdust, wood, beeswax, and wheat paste.[5][44][45] Zhu Xi (1130–1200) was inspired by the raised-relief map of Huang Shang and so made his own portable map made of wood and clay which could be folded up from eight hinged pieces.[46][45] Later, Ibn Battuta (1304–1377) described a raised-relief map while visiting Gibraltar, while European raised-relief maps started with a Paul Dox who made one to represent Kufstein, Austria, in 1510.[47][48] The Englishman John Evelyn (1620–1706), in his 1665 paper featured in the Philosophical Transactions of the Royal Society, wrote that the raised-relief map was something new from France.[47]
[edit] Pharmacology
- Further information: Traditional Chinese medicine
For pharmacology, Shen wrote of the difficulties of adequate diagnosis and therapy, as well as the proper selection, preparation, and administration of drugs.[49] He held great concern for detail and philological accuracy in identification, use and cultivation of different types of medicinal herbs, such as in which months medicinal plants should be gathered, their exact ripening times, which parts should be used for therapy; for domesticated herbs he wrote about planting times, fertilization, and other matters of horticulture.[50] In the realms of botany, zoology, and mineralogy, Shen Kuo documented and systematically described hundreds of different plants, agricultural crops, rare vegetation, animals, and minerals found in China.[51][52][53][54] For example, Shen noted that the mineral orpiment was used to quickly erase writing errors on paper.[55]
[edit] Engineering
The writing of Shen Kuo is the only source for the date when the drydock was first used in China.[56] Shen Kuo wrote that during the Xi-Ning reign (1068–1077), the court official Huang Huaixin devised a plan for repairing 60 m (200 ft) long palatial boats that were a century old; essentially, Huang Huaixin devised the first Chinese drydock for suspending boats out of water.[56] These boats were then placed in a roof-covered dock warehouse to protect them from weathering.[56] Shen also wrote about the effectiveness of the new invention (i.e. by the 10th century engineer Qiao Weiyo) of the pound lock to replace the old flash lock design used in canals.[57] He wrote that it saved the work of five hundred annual labors, annual costs of up to 1,250,000 strings of cash, and increased the size limit of boats accommodated from 21 tons/21000 kg to 113 tons/115000 kg.[57]
If it were not for Shen Kuo's analysis and quoting in his Dream Pool Essays of the writings of the architect Yu Hao (fl. 970), the latter's work would have been lost to history.[58]d[›] Yu designed a famous wooden pagoda that burned down in 1044 and was replaced in 1049 by a brick pagoda (the 'Iron Pagoda') of similar height, but not of his design. From Shen's quotation—or perhaps Shen's own paraphrasing of Yu Hao's Timberwork Manual (木經; Mujing)—shows that already in the 10th century there was a graded system of building unit proportions, a system which Shen states had become more precise in his time but stating no one could possibly reproduce such a sound work.[59][60] However, he did not anticipate the more complex and matured system of unit proportions embodied in the extensive written work by scholar-official Li Jie (1065–1110), the Treatise on Architectural Methods (營造法式; Yingzao Fashi) of 1103.[61][60] Klaas Ruitenbeek states that the version of the Timberwork Manual quoted by Shen is most likely Shen's summarization of Yu's work or a corrupted passage of the original by Yu Hao, as Shen writes: "According to some, the work was written by Yu Hao."[59]
[edit] Anatomy
The Chinese had long taken an interest in examining the human body. For example, in 16 AD the Xin Dynasty usurper Wang Mang called for the dissection of an executed man, to examine his arteries and viscera in order to discover cures for illnesses.[62] Shen also took interest in human anatomy, dispelling the long-held Chinese theory that the throat contained three valves, writing, "When liquid and solid are imbibed together, how can it be that in one's mouth they sort themselves into two throat channels?"[50] Shen maintained that the larynx was the beginning of a system that distributed vital qi from the air throughout the body, and that the esophagus was a simple tube that dropped food into the stomach.[63] Following Shen's reasoning and correcting the findings of the dissection of executed bandits in 1045, an early 12th century Chinese account of a bodily dissection finally supported Shen's belief in two throat valves, not three.[64] Also, the later Song Dynasty judge and early forensic expert Song Ci (1186–1249) would promote the use of autopsy in order to solve homicide cases, as written in his Collected Cases of Injustice Rectified.[65]
[edit] Mathematics and optics
- Further information: Chinese mathematics
In the broad field of mathematics, Shen Kuo mastered many practical mathematical problems, including many complex formulas for geometry,[66] 'packing' equations for calculus,[67] and chords and arcs problems employing trigonometry.[68] Shen addressed problems of writing out very large numbers, as large as 1043.[69] Shen's "technique of small increments" laid the foundation in Chinese mathematics for packing problems involving equal difference series.[69] Sal Restivo writes that Shen used summation of higher series to ascertain the number of kegs which could be piled in layers in a space shaped like the frustum of a rectangular pyramid.[70] In his formula "technique of intersecting circles", he created an approximation of the arc of a circle s given the diameter d, sagita v, and length of the chord c subtending the arc, the length of which he approximated as s = c + 2v2/d.[69] Restivo writes that Shen's work in the lengths of arcs of circles provided the basis for spherical trigonometry developed in the 13th century by Guo Shoujing (1231–1316).[70] He also simplified the counting rods technique by outlining short cuts in algorithm procedures used on the counting board, an idea expanded on by the mathematician Yang Hui (1238–1298).[71] Victor J. Katz asserts that Shen's method of "dividing by 9, increase by 1; dividing by 8, increase by 2," was a direct forerunner to the rhyme scheme method of repeated addition "9, 1, bottom add 1; 9, 2, bottom add 2".[72]
Shen wrote extensively about what he had learned while working for the state treasury, including mathematical problems posed by computing land tax, estimating requirements, currency issues, metrology, and so forth.[73] Shen once computed the amount of terrain space required for battle formations in military strategy,[74] and also computed the longest possible military campaign given the limits of human carriers who would bring their own food and food for other soldiers.[75] Shen wrote about the earlier Yi Xing (672–717), a Buddhist monk who applied an early escapement mechanism to a water-powered celestial globe.[76] By using mathematical permutations, Shen described Yi Xing's calculation of possible positions on a go board game. Shen calculated the total number for this using up to five rows and twenty five game pieces, which yielded the number 847,288,609,443.[77][78]
Shen Kuo experimented with the pinhole camera and burning mirror as the ancient Chinese Mohists had done in the 4th century BC. Although the Iraqi Muslim scientist Ibn al-Haytham (965–1039) was the first to experiment with camera obscura, Shen Kuo was the first to apply geometrical and quantitative attributes to the camera obscura, just several decades after Ibn al-Haytham's death.[79] Using a fitting metaphor, Shen compared optical image inversion to an oarlock and waisted drum.[80] He also discussed focal points and noted that the image in a concave mirror is inverted.[81] Shen, who never asserted that he was the first to experiment with camera obscura, hints in his writing that camera obscura was dealt with in the Miscellaneous Morsels from Youyang written by Duan Chengshi (d. 863) during the Tang Dynasty (618–907), in regards to the inverted image of a Chinese pagoda by a seashore.[79]
[edit] Magnetic needle compass
- Further information: List of Chinese inventions
Since the time of the engineer and inventor Ma Jun (c. 200–265), the Chinese had used a mechanical device known as the South Pointing Chariot in order to navigate on land (and possibly at sea, as the Song Shu text of c. 500 alludes). This device was especially impressive, since it featured the use of a differential gear, an essential component used in the correct steering and application of equal amount of torque for the wheels of all modern automobiles. In 1044 the Collection of the Most Important Military Techniques (武經總要; Wujing Zongyao) recorded that fish-shaped objects cut from sheet iron, magnetized by thermoremanence (essentially, heating that produced weak magnetic force), and placed in a water-filled bowl enclosed by a box were used for directional pathfinding alongside the South Pointing Chariot.[82][83]
However, it was not until the time of Shen Kuo that the earliest magnetic compasses would be used for navigation. In his written work, Shen Kuo made one of the first references in human history to the magnetic compass-needle, the concept of true north, and its use for navigation at sea.[16][84] He wrote that steel needles were magnetized once they were rubbed with lodestone, and that they were put in floating position or in mountings; he described the suspended compass as the best form to be used, and noted that the magnetic needle of compasses pointed either south or north.[82][85] Shen Kuo asserted that the needle will point south but with a deviation,[85] stating "[the magnetic needles] are always displaced slightly east rather than pointing due south."[82]
Shen Kuo wrote that it was preferable to use the twenty-four-point rose instead of the old eight compass cardinal points — and the former was recorded in use for navigation shortly after Shen's death.[5] The preference of use for the twenty-four-point-rose compass may have arisen from Shen's finding of a more accurate astronomical meridian, determined by his measurement between the polestar and true north;[5] however, it could also have been inspired by geomantic beliefs and practices.[5] The book of the author Zhu Yu, the Pingzhou Table Talks published in 1119 (written from 1111 to 1117), was the first record of use of a compass for seafaring navigation.[84] However, Zhu Yu's book recounts events back to 1086, when Shen Kuo was writing the Dream Pool Essays; this meant that in Shen's time the compass might have already been in navigational use.[86] In any case, Shen Kuo's writing on magnetic compasses has proved invaluable for understanding China's earliest use of the compass for seafaring navigation.
[edit] Archaeology
- Further information: Song Dynasty#Archaeology
Many of Shen Kuo's contemporaries were interested in antiquarian pursuits of collecting old artworks.[88] They were also interested in archaeological pursuits, although for rather different reasons than why Shen Kuo held an interest in archaeology. While Shen's educated Confucian contemporaries were interested in obtaining ancient relics and antiques in order to revive their use in rituals, Shen was more concerned with how items from archeological finds were originally manufactured and what their functionality would have been, based on empirical evidence.[89] Shen Kuo criticized those in his day who reconstructed ancient ritual objects using only their imagination and not the tangible evidence from archeological digs or finds.[89] Shen also disdained the notion of others that these objects were products of the "sages" or the aristocratic class of antiquity, rightfully crediting the items' manufacture and production to the common working people and artisans of previous eras.[89] Fraser and Haber write that Shen Kuo "advocated the use of an interdisciplinary approach to archaeology and practiced such an approach himself through his work in metallurgy, optics, and geometry in the study of ancient measures."[89]
While working in the Bureau of Astronomy, Shen Kuo's interest in archaeology and old relics led him to reconstruct an armillary sphere from existing models as well as from ancient texts that could provide additional information.[89] Shen used ancient mirrors while conducting his optics experiments.[89] He observed ancient weaponry, describing the scaled sight devices on ancient crossbows and the ancients' production of swords with composite blades that had a midrib of wrought iron and low-carbon steel while having two sharp edges of high-carbon steel.[89] Being a knowledgeable musician, Shen also suggested suspending an ancient bell by using a hollow handle.[89] In his assessment of the carved reliefs of the ancient Zhuwei Tomb, Shen stated that the reliefs demonstrate genuine Han Dynasty (202 BC–220 AD) era clothing.[90]
After unearthing an ancient crossbow device from a house's garden in Haichow, Jiangsu, Shen discovered that the cross-wire grid sighting device, marked in graduated measurements on the stock, could be used to calculate the height of a distant mountain in the same way that mathematicians could apply right-angle triangles to measure height.[91] Needham asserts Shen had discovered the survey device known as Jacob's staff, which was not described elsewhere until the Provençal Jewish mathematician Levi ben Gerson (1288–1344) wrote of it in 1321.[92] Shen wrote that while viewing the whole of a mountain, the distance on the instrument was long, but while viewing a small part of the mountainside the distance was short due to the device's cross piece that had to be pushed further away from the observer's eye, with the graduation starting on the further end.[91] He wrote that if one placed an arrow on the device and looked past its end, the degree of the mountain could be measured and thus its height could be calculated.[91]
[edit] Geology
The ancient Greek Aristotle (384 BC–322 BC) wrote in his Meteorology of how the earth had the potential for physical change, including the belief that all rivers and seas at one time did not exist where they were, and were dry. The Greek writer Xenophanes (570 BC–480 BC) wrote of how inland marine fossils were evidence that massive periodic flooding had wiped out mankind several times in the past, but never wrote of land formation or shifting seashores.[93] Du Yu (222–285) a Chinese Jin Dynasty officer, believed that the land of hills would eventually be leveled into valleys and valleys would gradually rise to form hills.[94] The Daoist alchemist Ge Hong (284–364) wrote of the legendary immortal Ma Gu; in a written dialogue by Ge, Ma Gu described how what was once the Eastern Sea (i.e. East China Sea) had transformed into solid land where mulberry trees grew, and would one day be filled with mountains and dry, dusty lands.[94] The later Persian Muslim scholar Abū Rayhān al-Bīrūnī (973–1048) hypothesized that India was once covered by the Indian Ocean while observing rock formations at the mouths of rivers.[95]
It was Shen Kuo who formulated a hypothesis about the process of land formation (geomorphology) based upon several observations as evidence. This included his observation of fossil shells in a geological stratum of a mountain hundreds of miles from the ocean. He inferred that the land was reshaped and formed by erosion of the mountains, uplift, and the deposition of silt, after observing strange natural erosions of the Taihang Mountains and the Yandang Mountain near Wenzhou.[96] He hypothesized that, with the inundation of silt, the land of the continent must have been formed over an enormous span of time.[97] While visiting the Taihang Mountains in 1074, Shen Kuo noticed strata of bivalve shells and ovoid rocks in a horizontal-running span through a cliff like a large belt.[97] Shen proposed that the cliff was once the location of an ancient seashore that by his time had shifted hundreds of miles east.[97] Shen wrote that in the Zhiping reign period (1064–1067) a man of Zezhou unearthed an object in his garden that looked like a serpent or dragon, and after examining it, concluded the dead animal had apparently turned to "stone".[98][99] The magistrate of Jincheng, Zheng Boshun, examined the creature as well, and noted the same scale-like markings that were seen on other marine animals.[98][99] Shen Kuo likened this to the "stone crabs" found in China.[98][99]
Shen also wrote that since petrified bamboos were found underground in a climatic area where they had never been known to be grown, climates naturally shifted geographically over time.[99][100] Around the year 1080, Shen Kuo noted that a landslide on the bank of a large river near Yanzhou (modern Yan'an) had revealed an open space several dozens of feet under the ground once the bank collapsed.[99][100] This underground space contained hundreds of petrified bamboos still intact with roots and trunks, "all turned to stone" as Shen Kuo wrote.[99][100] Shen Kuo noted that bamboos do not grow in Yanzhou, located in northern China, and he was puzzled during which previous dynasty the bamboos could have grown.[99][100] Considering that damp and gloomy low places provide suitable conditions for the growth of bamboo, Shen deduced that the climate of Yanzhou must have fit that description in very ancient times.[99][100] Although this would have intrigued many of his readers, the study of paleoclimatology in medieval China never developed into an established discipline.
The philosopher Zhu Xi (1130–1200) wrote of this curious natural phenomenon of fossils as well. He was known to have read the works of Shen Kuo.[99] Shen's description of soil erosion and weathering predated that of Georgius Agricola in his book of 1546, De veteribus et novis metallis.[101] Furthermore, Shen's theory of sedimentary deposition predated that of James Hutton, who published his groundbreaking work in 1802 (considered the foundation of modern geology).[101] Historian Joseph Needham likened Shen's account to that of the Scottish scientist Roderick Murchison (1792–1871), who was inspired to become a geologist after observing a providential landslide.
.jpg){kind=link}