Difference between revisions of "Zhang Heng" - New World Encyclopedia

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'''Zhang Heng''' ({{zh-tspw|t=張衡|s=张衡|p=Zhāng Héng|w=Chang Heng}}) (CE 78–139) was a [[China|Chinese]] [[polymath]], being a [[Chinese astronomy|astronomer]], [[Chinese mathematics|mathematician]], [[List of Chinese inventions|inventor]], [[Chinese geography|geographer]], [[History of cartography#China|cartographer]], [[Chinese art|artist]], [[Chinese poetry|poet]], [[Government of the Han Dynasty|statesman]], and [[Chinese literature|literary scholar]]. He was from [[Nanyang, Henan|Nanyang]], [[Henan]], and lived during the [[Eastern Han Dynasty]] (CE 25–220).  
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'''Zhang Heng''' ({{zh-tspw|t=張衡|s=张衡|p=Zhāng Héng|w=Chang Heng}}) (CE 78–139) was a [[China|Chinese]] [[polymath]], being a [[Chinese astronomy|astronomer]], [[Chinese mathematics|mathematician]], [[List of Chinese inventions|inventor]], [[Chinese geography|geographer]], [[History of cartography#China|cartographer]], [[Chinese art|artist]], [[Chinese poetry|poet]], [[Government of the Han Dynasty|statesman]], and [[Chinese literature|literary scholar]]. He was from [[Nanyang, Henan|Nanyang]], [[Henan]], and lived during the [[Eastern Han Dynasty]] (25 – 220 C.E.).  
  
Zhang made numerous contributions which gave lasting influences on the development of intellectual, technological, and literary traditions of China. To list some, Zhang was the first person to invent a seismometer. The device was able to determine the cardinal direction of earthquakes. Zhang Heng is also the first person to have applied hydraulic motive power to rotate an armillary sphere, an astronomical instrument representing the celestial sphere.
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Zhang made numerous contributions which gave lasting influences on the development of intellectual, technological, and literary traditions of China. Among his many accomplishments, Zhang is credited with inventing a [[seismometer]]. His device was able to determine the cardinal direction of earthquakes. Zhang Heng is also the first person to have applied [[hydraulic motive power]] to rotate an [[armillary sphere]], an astronomical instrument representing the celestial sphere.  
 
 
As an astronomer, Zhang catalogued 2,500 stars, and recognized 124 constellations, which exceeds the works by [[Hipparchus]] (c. 190-c.120 B.C.E.) or [[Ptolemy]] (CE 83-161) who cataloged over 1,000. Zhang also invented the [[odometer]], often referenced as [[Archimedes]] (c. 287 ®C 212 B.C.E.) As a cartographer, Zhang was the first to make a mathematical grid reference.
 
 
 
Zhang was one of the best known writers in literature and poetry in the Eastern Han Dynasty. He wrote [[science fiction]], [[cosmology|cosmological]], [[ethnography|ethnographic]] literature, and started a new poetic style. He was also counted as one of six best artists in the Eastern Han. In his poem, Zhang often expressed his [[morality|moral]] criticism against decadent, lavish life style of politicians of his time.
 
 
 
==Overview==
 
 
 
Zhang Heng was educated in the capital cities of [[Luoyang]] and [[Chang'an]], and began his career as a minor civil servant in Nanyang. Eventually, he became Chief Astronomer, Prefect of the Majors for Official Carriages, and then Palace Attendant at the imperial court. His uncompromising stances on certain historical and calendrical issues led to Zhang being considered a controversial figure, which prevented him from becoming an official court historian. His political rivalry with the palace [[eunuch]]s during the reign of [[Emperor Shun of Han|Emperor Shun]] (r. 125®C144) led to his decision to retire from the central court to serve as an administrator of Hejian, in [[Hebei]]. He returned home to Nanyang for a short time, before being recalled to serve in the capital once more in 138. He died there a year later, in 139.
 
 
 
Zhang applied his extensive knowledge of mechanics and gears in several of his inventions. He invented the world's first [[Hydraulics|water-powered]] [[armillary sphere]], to represent astronomical observation;<ref name="needham volume 4 30"/> improved the inflow [[water clock]] by adding another tank;<ref name="needham volume 4 part 2 479 footnote e">Needham Volume 4, Part 2, 479 footnote e.</ref> and invented the world's first [[seismometer]], which discerned the [[cardinal direction]] of an [[earthquake]] {{convert|500|km|mi|abbr=on}} away.<ref name="needham volume 4 30">Needham, Volume 4, 30.</ref><ref name="wright 66">Wright, 66.</ref><ref name="huang 64">Huang, 64.</ref> Furthermore, he improved previous Chinese calculations of the formula for [[pi]]. In addition to documenting about 2,500 stars in his extensive [[star catalogue]], Zhang also posited theories about the [[Moon]] and its relationship to the [[Sun]]; specifically, he discussed the Moon's sphericity, its illumination by reflecting sunlight on one side and remaining dark on the other, and the nature of [[Solar eclipse|solar]] and [[lunar eclipse|lunar]] [[eclipse]]s. His ''[[Fu (poetry)|fu]]'' (rhapsody) and ''[[Shi (poetry)|shi]]'' poetry were renowned and commented on by later Chinese writers. Zhang received many posthumous honors for his scholarship and ingenuity, and is considered a [[polymath]] by some scholars. Some modern scholars have also compared his work in astronomy to that of [[Ptolemy]] (CE&nbsp;86–161).
 
  
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As an astronomer, Zhang cataloged 2500 stars, and recognized 124 distinct constellations, exceeding [[Hipparchus]] (c. 190 - c.120 B.C.E.) or [[Ptolemy]] (83-161 C.E.) who cataloged more than 1000. Zhang also invented the first [[odometer]], often referenced as [[Archimedes]] (c. 287 - 212 B.C.E.). As a [[Cartography|cartographer]], Zhang was the first to make a mathematical grid reference.
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Zhang was one of the best known writers in literature and [[poetry]] in the [[Eastern Han Dynasty]]. He wrote [[science fiction]], [[cosmology|cosmological]], [[ethnography|ethnographic]] literature, and started a new poetic style. He was also numbered as one of six best artists in the Eastern Han. In his poetry Zhang often expressed his [[morality|moral]] criticism against decadent, lavish life styles of politicians of his time.
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{{ChineseText}}
 
==Life of Zhang Heng==
 
==Life of Zhang Heng==
 
===Early life===
 
===Early life===
[[Image:Painted figures on a lacquer basket, Eastern Han Dynasty2.jpg|thumb|right|220px|A 2nd-century [[Lacquerware|lacquer-painted]] scene on a basket box showing famous figures from Chinese history who were paragons of filial piety; Zhang Heng became well-versed at an early age in the [[Five Classics|Chinese classics]] and the philosophy of China's earlier sages.]]
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[[Image:Painted figures on a lacquer basket, Eastern Han Dynasty2.jpg|thumb|right|200px|A second-century [[Lacquerware|lacquer-painted]] scene on a basket box showing famous figures from Chinese history who were paragons of [[filial piety]]; Zhang Heng became well-versed at an early age in the [[Five Classics|Chinese classics]] and the [[philosophy]] of China's earlier sages.]]
Born in the town of Xi'e in Nanyang Commandery (located north of modern [[Nanyang, Henan|Nanyang City]], [[Henan]] province), Zhang Heng came from a distinguished but not very affluent family.<ref name="crespigny 1049"/><ref name="xiao knechtges 397">Xiao and Knechtges, 397.</ref><ref name="yan 127">Yan, 127.</ref> His grandfather, Zhang Kan, had been governor of a commandery, and one of the leaders who supported the restoration of the [[Han Dynasty]] by [[Emperor Guangwu of Han|Emperor Guangwu]] (r.&nbsp;25–57), following the death of the usurper [[Wang Mang]] and his short-lived [[Xin Dynasty]] (CE&nbsp;9–23).<ref name="crespigny 1049">Crespigny, 1049.</ref><ref name="xiao knechtges 398"/><ref name="asiapac 120">Asiapac, 120.</ref><ref name="loewe 1968 105">Loewe (1968), 105.</ref> At age ten, Zhang's father died, leaving him in the care of his mother and grandmother.<ref name="asiapac 120"/> An accomplished writer in his youth, Zhang left home in 95 to pursue his studies at universities in the ancient capitals of [[Chang'an]] and [[Luoyang]].<ref name="crespigny 1049"/> While traveling to Luoyang, Zhang passed by a [[hot spring]] near Mount Li and dedicated one of his earliest [[Fu (poetry)|fu poems]] to it, the ''Wenquan'' (溫泉).<ref name="neinhauser 211">Neinhauser et al., 211.</ref> After studying for some years at Luoyang's Imperial University ([[Taixue]]), he became well-versed in the [[Chinese classic texts|classics]], and befriended notable persons, such as the mathematician and calligrapher [[Cui Yuan (Han Dynasty)|Cui Yuan]] (78–143), the official and philosophical commentator [[Ma Rong]] (79–166), and the philosopher [[Wang Fu (philosopher)|Wang Fu]] (78–163).<ref name="crespigny 1049"/><ref name="yan 127"/> Government authorities offered Zhang appointments to several offices, including a position as one of the [[Three Excellencies]], yet he acted modestly and turned down those positions.<ref name="crespigny 1049"/><ref name="neinhauser 211"/> At age twenty-three, he returned home with the title "Officer of Merit in Nanyang," serving as the master of documents under the administration of Governor Bao De (in office from 103–111).<ref name="crespigny 1049"/><ref name="xiao knechtges 398"/><ref name="yan 127"/> As he was charged with composing inscriptions and dirges for Bao De, he gained experience in writing official documents.<ref name="xiao knechtges 398"/> As Officer of Merit in the commandery, he was also responsible for local appointments to office and recommendations to the capital of nominees for higher office.<ref name="crespigny 1229">Crespigny, 1229.</ref> He spent much of his time composing [[Rhapsody (music)|rhapsodies]] on the capital cities. When Bao De was recalled to the capital in 111, to serve as a minister of finance, Zhang continued his literary work at home in Xi'e.<ref name="crespigny 1049"/><ref name="xiao knechtges 398"/><ref name="neinhauser 211"/> Zhang Heng began his studies in astronomy at the age of thirty, and began publishing his works in [[Chinese astronomy|astronomy]] and [[Chinese mathematics|mathematics]].<ref name="xiao knechtges 398"/>
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Born in the town of Xi'e in Nanyang Commandery (located north of modern [[Nanyang, Henan|Nanyang City]], [[Henan]] province), Zhang Heng came from a distinguished but not very affluent family.<ref name="crespigny 1049"/>Rafe de Crespigny. 2007. ''A Biographical Dictionary of Later Han to the Three Kingdoms (23-220 C.E.)''. (Leiden: Koninklijke Brill. ISBN 9004156054), 1049.</ref><ref name="xiao knechtges 397">Tong Xiao and David Knechtges. 1996. ''Wen Xuan, Or, Selections of Refined Literature.'' (Princeton: Princeton University Press. ISBN 0691021260), 397.</ref><ref name="yan 127">Hong-sen Yan. 2007. ''Reconstruction Designs of Lost Ancient Chinese Machinery.'' (Dordrecht: Springer. ISBN 1402064594), 127.</ref> His grandfather, Zhang Kan, had been governor of a commandery, and one of the leaders who supported the restoration of the [[Han Dynasty]] by [[Emperor Guangwu of Han|Emperor Guangwu]] (r.&nbsp;25–57), following the death of the usurper [[Wang Mang]] and his short-lived [[Xin Dynasty]] (9–23 C.E.).<ref name="crespigny 1049">Crespigny, 1049.</ref><ref name="xiao knechtges 398"/><ref name="asiapac 120">''Asiapac Editorial,'' (2004). ''Origins of Chinese Science and Technology,'' Translated by Yang Liping and Y.N. Han. (Singapore: Asiapac Books Pte. Ltd. ISBN 9812293760), 120.</ref><ref name="loewe 1968 105">Michael Loewe. 1968. ''Everyday Life in Early Imperial China during the Han Period 202 B.C.E.–CE 220.'' (London: B.T. Batsford Ltd.; New York: G.P. Putnam's Sons), 105.</ref> At age ten, Zhang's father died, leaving him in the care of his mother and grandmother.<ref name="asiapac 120"/> An accomplished writer in his youth, Zhang left home in 95 to pursue his studies at universities in the ancient capitals of [[Chang'an]] and [[Luoyang]].<ref name="crespigny 1049"/> While traveling to Luoyang, Zhang passed by a [[hot spring]] near Mount Li and dedicated one of his earliest [[Fu (poetry)|fu poems]] to it, the ''Wenquan'' (溫泉).<ref name="neinhauser 211">William H. Neinhauser, Charles Hartman, Y.W. Ma, and Stephen H. West. 1986. ''The Indiana Companion to Traditional Chinese Literature: Volume 1.'' (Bloomington: Indiana University Press. ISBN 0253329833), 211.</ref> After studying for some years at Luoyang's Imperial University ([[Taixue]]), he became well-versed in the [[Chinese classic texts|classics]], and befriended notable persons, such as the mathematician and calligrapher [[Cui Yuan (Han Dynasty)|Cui Yuan]] (78 – 143), the official and philosophical commentator [[Ma Rong]] (79 – 166), and the philosopher [[Wang Fu (philosopher)|Wang Fu]] (78 – 163).<ref name="crespigny 1049"/><ref name="yan 127"/> Government authorities offered Zhang appointments to several offices, including a position as one of the [[Three Excellencies]], yet he acted modestly and turned down those positions.<ref name="crespigny 1049"/><ref name="neinhauser 211"/> At age 23, he returned home with the title "Officer of Merit in Nanyang," serving as the master of documents under the administration of Governor Bao De (in office from 103–111).<ref name="crespigny 1049"/><ref name="xiao knechtges 398"/><ref name="yan 127"/> As he was charged with composing inscriptions and dirges for Bao De, he gained experience in writing official documents.<ref name="xiao knechtges 398"/> As Officer of Merit in the commandery, he was also responsible for local appointments to office and recommendations to the capital of nominees for higher office.<ref name="crespigny 1229">Crespigny, 1229.</ref> He spent much of his time composing [[Rhapsody (music)|rhapsodies]] on the capital cities. When Bao De was recalled to the capital in the year 111, to serve as a minister of finance, Zhang continued his literary work at home in Xi'e.<ref name="crespigny 1049"/><ref name="xiao knechtges 398"/><ref name="neinhauser 211"/> Zhang Heng began his studies in [[astronomy]] at the age of 30, and began publishing his works in [[Chinese astronomy|astronomy]] and [[Chinese mathematics|mathematics]].<ref name="xiao knechtges 398"/>
  
 
===Official career===
 
===Official career===
In 112, Zhang was summoned to the court of [[Emperor An of Han]] (r.&nbsp;106®C125), who had heard of Zhang's expertise in mathematics.<ref name="xiao knechtges 398"/> When he was nominated to serve at the capital, Zhang was escorted by carriage°™a symbol of his official status°™to Luoyang, where he became a court gentleman working for the [[Three Excellencies|Imperial Secretariat]].<ref name="crespigny 1049"/><ref name="xiao knechtges 398"/> He was promoted to Chief Astronomer for the Han court under Emperor An, serving his first term from 115®C120 and his second under the succeeding emperor from 126®C132.<ref name="xiao knechtges 398"/> As Chief Astronomer, Zhang was a subordinate of the Minister of Ceremonies, ranked just below the Three Excellencies.<ref name="crespigny 1222">Crespigny, 1222.</ref> In addition to recording heavenly observations and portents, preparing the calendar, and reporting which days were auspicious or not, Zhang was also in charge of an advanced literacy test for all candidates of the Imperial Secretariat and [[Censorate]] (who were expected to know at least 9,000 [[Chinese characters]] and all major writing styles).<ref name="crespigny 1222"/><ref>Bielenstein, 9 & 19.</ref> Under Emperor An, Zhang also served as Prefect of the Majors for Official Carriages under the Ministry of Guards, in charge of the reception of memorials (containing policy and administrative suggestions) submitted to the throne as well as nominees for official appointments.<ref name="crespigny 1049 1223">Crespigny, 1049 & 1223.</ref><ref name="yan 128"/>
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In 112, Zhang was summoned to the court of [[Emperor An of Han]] (r.106 c. 125), who had heard of Zhang's expertise in [[mathematics]].<ref name="xiao knechtges 398"/> When he was nominated to serve at the capital, Zhang was escorted by carriage (a symbol of his official status) to Luoyang, where he became a court gentleman working for the [[Three Excellencies|Imperial Secretariat]].<ref name="crespigny 1049"/><ref name="xiao knechtges 398"/> He was promoted to Chief Astronomer for the Han court under Emperor An, serving his first term from 115 c. 120 and his second under the succeeding emperor from 126 - 132.<ref name="xiao knechtges 398"/> As Chief Astronomer, Zhang was a subordinate of the Minister of Ceremonies, ranked just below the Three Excellencies.<ref name="crespigny 1222">Crespigny, 1222.</ref> In addition to recording heavenly observations and portents, preparing the [[calendar]], and reporting which days were auspicious or not, Zhang was also in charge of an advanced literacy test for all candidates of the Imperial Secretariat and [[Censorate]] (who were expected to know at least 9000 [[Chinese characters]] and all major writing styles).<ref name="crespigny 1222"/><ref>Hans Bielenstein. 1980. ''The Bureaucracy of Han Times.'' (Cambridge: Cambridge University Press. ISBN 0521225108), 9 & 19.</ref> Under Emperor An, Zhang also served as Prefect of the Majors for Official Carriages under the Ministry of Guards, in charge of the reception of memorials (containing policy and administrative suggestions) submitted to the throne as well as nominees for official appointments.<ref name="crespigny 1049 1223">Crespigny, 1049 & 1223.</ref>
  
[[Image:Cernuschi Museum 20060812 068.jpg|thumb|left|200px|A Western Han [[terra cotta]] cavalier figurine wearing robes and a hat. As Chief Astronomer, Zhang Heng earned a fixed salary and rank of 600&nbsp;bushels of grain (which was mostly commuted to payments in [[Chinese coins|coinage currency]] or bolts of [[silk]]), and so he would have worn a specified type of robe, ridden in a specified type of carriage, and held a unique emblem that marked his status in the official hierarchy.<ref name="crespigny 1050"/><ref>Loewe (1968), 38–39 & 42.</ref>]]
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[[Image:Cernuschi Museum 20060812 068.jpg|thumb|left|200px|A Western Han [[terra cotta]] cavalier figurine wearing robes and a hat. As Chief Astronomer, Zhang Heng earned a fixed salary and rank of 600&nbsp;bushels of [[grain]] (which was mostly commuted to payments in [[Chinese coins|coinage currency]] or bolts of [[silk]]), and so he would have worn a specified type of robe, ridden in a specified type of carriage, and held a unique emblem that marked his status in the official hierarchy.<ref name="crespigny 1050">Crespigny, 1050.</ref><ref>Loewe, 1968, 38–39 & 42.</ref>]]
When the government official Dan Song proposed the [[Chinese calendar]] should be reformed in 123 to adopt certain [[Apocrypha|apocryphal teachings]], Zhang opposed the idea. He considered the teachings to be of questionable stature and believed they could introduce errors.<ref name="crespigny 1049"/> Others shared Zhang's opinion and the calendar was not altered, yet Zhang's proposal that apocryphal writings should be banned was rejected.<ref name="crespigny 1049"/> The officials Liu Zhen and Liu Taotu, members of a committee to compile the dynastic history ''Dongguan Hanji'' (東觀漢記), sought permission from the court to consult Zhang Heng.<ref name="crespigny 1049"/> However, Zhang was barred from assisting the committee due to his controversial views on apocrypha and his objection to the relegation of [[Emperor Gengshi of Han|Emperor Gengshi's]] (r.&nbsp;23–25) role in the restoration of the Han Dynasty as lesser than Emperor Guangwu's.<ref name="crespigny 1049 1050">Crespigny, 1049–1050.</ref><ref name="mansvelt-beck 26">Mansvelt-Beck, 26.</ref> Liu Zhen and Liu Taotu were Zhang's only historian allies at court, and after their deaths Zhang had no further opportunities for promotion to the prestigious post of court historian.<ref name="crespigny 1049 1050"/>
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When the government official Dan Song proposed the [[Chinese calendar]] should be reformed in 123 to adopt certain [[Apocrypha|apocryphal teachings]], Zhang opposed the idea. He considered the teachings to be of questionable stature and believed they could introduce errors.<ref name="crespigny 1049"/> Others shared Zhang's opinion and the [[calendar]] was not altered, yet Zhang's proposal that apocryphal writings should be banned was rejected.<ref name="crespigny 1049"/> The officials Liu Zhen and Liu Taotu, members of a committee to compile the dynastic history ''Dongguan Hanji'' (東觀漢記), sought permission from the court to consult Zhang Heng.<ref name="crespigny 1049"/> However, Zhang was barred from assisting the committee due to his controversial views on apocrypha and his objection to the relegation of [[Emperor Gengshi of Han|Emperor Gengshi's]] (r. 23–25) role in the restoration of the Han Dynasty as lesser than Emperor Guangwu's.<ref name="crespigny 1049 1050">Crespigny, 1049–1050.</ref><ref name="mansvelt-beck 26">B.J. Mansvelt-Beck. 1990. ''The Treatises of Later Han: Their Author, Sources, Contents, and Place in Chinese Historiography.'' (Leiden: E.J. Brill. ISBN 9004088954), 26.</ref> Liu Zhen and Liu Taotu were Zhang's only historian allies at court, and after their deaths Zhang had no further opportunities for promotion to the prestigious post of court historian.<ref name="crespigny 1049 1050"/>
  
Despite this setback in his official career, Zhang was reappointed as Chief Astronomer in 126 after [[Emperor Shun of Han]] (r. 125–144) ascended to the throne.<ref name="crespigny 1050"/><ref name="declercq 65">Declercq, 65.</ref> His intensive astronomical work was rewarded only with the rank and salary of 600&nbsp;bushels, or ''shi'', of grain (mostly commuted to [[Chinese coins|coin cash]] or bolts of [[silk]]).<ref name="crespigny 1050"/><ref name="loewe 1968 42">Loewe (1968). 42.</ref> To place this number in context, in a hierarchy of twenty official ranks, the lowest-paid official earned the rank and salary of 100&nbsp;bushels and the highest-paid official earned 10,000&nbsp;bushels during the Han.<ref name="wang 137">Wang, 137.</ref> The 600-bushel rank was the lowest the emperor could directly appoint to a central government position; any official of lower status was overseen by central or provincial officials of high rank.<ref name="wang 142">Wang, 142 & 145.</ref>
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Despite this setback in his official career, Zhang was reappointed as Chief Astronomer in 126 after [[Emperor Shun of Han]] (r. 125–144) ascended to the throne.<ref name="crespigny 1050"/><ref name="declercq 65">Dominik Declercq. 1998. ''Writings Against the State: Political Rhetorics in Third and Fourth Century China.'' (Leiden: Koninklijke Brill NV.), 65.</ref> His intensive astronomical work was rewarded only with the rank and salary of 600&nbsp;bushels, or ''shi,'' of grain (mostly commuted to [[Chinese coins|coin cash]] or bolts of [[silk]]).<ref name="crespigny 1050"/><ref name="loewe 1968 42">Loewe, 1968, 42.</ref> To place this number in context, in a hierarchy of 20 official ranks, the lowest-paid official earned the rank and salary of 100&nbsp;bushels and the highest-paid official earned 10,000&nbsp;bushels during the Han.<ref name="wang 137">Wang, 137.</ref> The 600-bushel rank was the lowest the emperor could directly appoint to a central government position; any official of lower status was overseen by central or provincial officials of high rank.<ref name="wang 142">Yu-ch'uan Wang, "An Outline of The Central Government of The Former Han Dynasty," ''Harvard Journal of Asiatic Studies'' 12 (1/2) (June 1949): 134–187. 142 & 145. </ref>
  
In 132, Zhang introduced an intricate [[seismometer]] to the court, which he claimed could detect the precise cardinal direction of a distant [[earthquake]].<ref name="minford lau 307">Minford & Lau, 307.</ref> On one occasion his device indicated that an earthquake had occurred in the northwest. As there was no perceivable tremor felt in the capital his political enemies were briefly able to relish the failure of his device,<ref name="minford lau 307"/> until a messenger arrived shortly afterwards to report that an earthquake had occurred about 400&nbsp;km (248&nbsp;mi) to 500&nbsp;km (310&nbsp;mi) northwest of Luoyang in [[Gansu]] province.<ref name="minford lau 307"/><ref name="balchin 26 27">Balchin, 26–27.</ref><ref name="needham volume 3 627">Needham, Volume 3, 627.</ref><ref name="krebs 31"/>
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In 132, Zhang introduced an intricate [[seismometer]] to the court, which he claimed could detect the precise cardinal direction of a distant [[earthquake]].<ref name="minford lau 307">John Minford and Joseph S.M. Lau. 2002. ''Classical Chinese literature: an anthology of translations.'' (New York: Columbia University Press. ISBN 0231096763), 307.</ref> On one occasion his device indicated that an earthquake had occurred in the northwest. As there was no perceivable tremor felt in the capital his political enemies were briefly able to relish the failure of his device,<ref name="minford lau 307"/> until a messenger arrived shortly afterwards to report that an earthquake had occurred about 400&nbsp;km (248&nbsp;mi) to 500&nbsp;km (310&nbsp;mi) northwest of Luoyang in [[Gansu]] province.<ref name="balchin 26 27">Jon Balchin. 2003. ''Science: 100 Scientists Who Changed the World.'' (New York: Enchanted Lion Books. ISBN 1592700179), 26–27. </ref><ref name="needham volume 3 627">Joseph Needham. 1986. ''Science and Civilization in China: Volume 3, Mathematics and the Sciences of the Heavens and the Earth.'' (Taipei: Caves Books, Ltd.), 627.</ref><ref name="krebs 31"/>
  
 
[[Image:Pottery palace 1.JPG|thumb|200px|[[Chinese ceramics|A pottery]] miniature [[Chinese palaces|of a palace]] made during the Han Dynasty; as a palace attendant, Zhang Heng had personal access to Emperor Shun and the right to escort him]]
 
[[Image:Pottery palace 1.JPG|thumb|200px|[[Chinese ceramics|A pottery]] miniature [[Chinese palaces|of a palace]] made during the Han Dynasty; as a palace attendant, Zhang Heng had personal access to Emperor Shun and the right to escort him]]
A year after Zhang presented his seismometer to the court, officials and candidates were asked to provide comments about a series of recent earthquakes which could be interpreted as signs of displeasure from Heaven.<ref name="crespigny 1050"/> The ancient Chinese viewed natural calamities as cosmological punishments for misdeeds that were perpetrated by the Chinese ruler or his subordinates on earth. In Zhang's memorial discussing the reasons behind these natural disasters, he criticized the new recruitment system of Zuo Xiong which fixed the age of eligible candidates for the title "[[Xiaolian|Filial and Incorrupt]]" at age forty.<ref name="crespigny 1050"/> The new system also transferred the power of the candidates' assessment to the Three Excellencies rather than the Generals of the Household, who by tradition oversaw the affairs of court gentlemen.<ref name="crespigny 1050"/> Although Zhang's memorial was rejected, his status was significantly elevated soon after to Palace Attendant, a position he used to influence the decisions of Emperor Shun.<ref name="crespigny 1050"/><ref name="yan 128"/> With this prestigious new position, Zhang earned a salary of 2,000&nbsp;bushels and had the right to escort the emperor.<ref name="crespigny 1225">Crespigny, 1225.</ref>
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A year after Zhang presented his seismometer to the court, officials and candidates were asked to provide comments about a series of recent [[earthquake]]s which could be interpreted as signs of displeasure from Heaven.<ref name="crespigny 1050">Crespigny, 1050.</ref> The ancient Chinese viewed natural calamities as cosmological punishments for misdeeds that were perpetrated by the Chinese ruler or his subordinates on earth. In Zhang's memorial discussing the reasons behind these natural disasters, he criticized the new recruitment system of Zuo Xiong which fixed the age of eligible candidates for the title "[[Xiaolian|Filial and Incorrupt]]" at age 40.<ref name="crespigny 1050"/> The new system also transferred the power of the candidates' assessment to the Three Excellencies rather than the Generals of the Household, who by tradition oversaw the affairs of court gentlemen.<ref name="crespigny 1050"/> Although Zhang's memorial was rejected, his status was significantly elevated soon after to Palace Attendant, a position he used to influence the decisions of Emperor Shun.<ref name="crespigny 1050"/><ref name="yan 128"/> With this prestigious new position, Zhang earned a salary of 2000&nbsp;bushels and had the right to escort the emperor.<ref name="crespigny 1225">Crespigny, 1225.</ref>
  
As Palace Attendant to Emperor Shun, Zhang Heng attempted to convince him that the court [[eunuch]]s represented a threat to the imperial court. Zhang pointed to specific examples of past court intrigues involving eunuchs, and convinced Shun that he should assume greater authority and limit their influence.<ref name="crespigny 1050"/> The eunuchs attempted to slander Zhang, who responded with a rhapsody called "Contemplating the Cosmos".<ref name="crespigny 1050"/><ref name="neinhauser 211 212"/> [[Rafe de Crespigny]] states that Zhang's rhapsody used imagery similar to [[Qu Yuan]]'s (340–278&nbsp;BCE) poem "[[Li Sao]]" and focused on whether or not good men should flee the corrupted world or remain virtuous within it.<ref name="crespigny 1050"/><ref name="neinhauser 211 212">Neinhauser et al., 211–212.</ref>
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As Palace Attendant to Emperor Shun, Zhang Heng attempted to convince him that the court [[eunuch]]s represented a threat to the imperial court. Zhang pointed to specific examples of past court intrigues involving eunuchs, and convinced Shun that he should assume greater authority and limit their influence.<ref name="crespigny 1050"/> The eunuchs attempted to slander Zhang, who responded with a rhapsody called "Contemplating the Cosmos".<ref name="crespigny 1050"/><ref name="neinhauser 211 212"/> [[Rafe de Crespigny]] states that Zhang's rhapsody used imagery similar to [[Qu Yuan]]'s (340–278 B.C.E.) poem "[[Li Sao]]" and focused on whether or not good men should flee the corrupted world or remain virtuous within it.<ref name="crespigny 1050"/><ref name="neinhauser 211 212">Neinhauser et al., 211–212. </ref>
 
[[Image:CMOC Treasures of Ancient China exhibit - pictorial brick depicting a courtyard scene.jpg|thumb|200px|Eastern Han tomb brick depicting the courtyard of a wealthy family's home. Zhang enjoyed a short period of retirement at his home in Xi'e, Nanyang, before being called back to the capital, where he died in 139.]]
 
[[Image:CMOC Treasures of Ancient China exhibit - pictorial brick depicting a courtyard scene.jpg|thumb|200px|Eastern Han tomb brick depicting the courtyard of a wealthy family's home. Zhang enjoyed a short period of retirement at his home in Xi'e, Nanyang, before being called back to the capital, where he died in 139.]]
  
 
===Retirement and death===
 
===Retirement and death===
  
Zhang retired from his position under Emperor Shun in 136,<ref name="crespigny 1050"/><ref name="xiao knechtges 398"/> following which he was appointed Chancellor of Hejian (in modern [[Hebei]]). During his two years in office<ref name="crespigny 1050"/><ref name="xiao knechtges 398"/> he worked to curtail the actions of the [[Kings of the Han Dynasty|local king]], Liu Zheng, and the powerful elite families to whom the king had granted special privileges.<ref name="crespigny 1050"/><ref name="xiao knechtges 398"/> After arresting several lawbreakers, Zhang gained a reputation among the people of Hejian as a strict administrator.<ref name="xiao knechtges 398"/><ref name="neinhauser 212">Neinhauser et al., 212.</ref> Zhang's writing at this time reflects his bitterness at being unable to effectively serve the emperor.<ref name="crespigny 1050"/><ref name="xiao knechtges 398"/> Zhang retired from office in 138, and returned home to Nanyang.<ref name="xiao knechtges 398"/><ref name="neinhauser 212"/> There he composed a [[Return to the Field (rhapsody)|rhapsody]] rejoicing over the opportunity his retirement gave him to read and to play his [[lute]].<ref name="crespigny 1050"/><ref name="neinhauser 212"/> A few months after his return home, Zhang was appointed to serve under the Imperial Secretariat and traveled back to the capital. He died there in 139, while still in office.<ref name="crespigny 1050 1051">Crespigny, 1050®C1051</ref> By the time of his death, Zhang had composed thirty-two written works on literature, philosophy, science, and mysticism.<ref name="crespigny 1051">Crespigny, 1051.</ref> He was buried in his hometown Xi'e, in Nanyang Commandery; his friend Cui Yuan composed the inscription for his tomb.<ref name="crespigny 1051"/><ref name="xiao knechtges 398"/>
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Zhang retired from his position under Emperor Shun in 136,<ref name="crespigny 1050"/><ref name="xiao knechtges 398"/> following which he was appointed Chancellor of Hejian (in modern [[Hebei]]). During his two years in office<ref name="crespigny 1050"/><ref name="xiao knechtges 398"/> he worked to curtail the actions of the [[Kings of the Han Dynasty|local king]], Liu Zheng, and the powerful elite families to whom the king had granted special privileges.<ref name="crespigny 1050"/><ref name="xiao knechtges 398"/> After arresting several lawbreakers, Zhang gained a reputation among the people of Hejian as a strict administrator.<ref name="xiao knechtges 398"/><ref name="neinhauser 212">Neinhauser et al., 212.</ref> Zhang's writing at this time reflects his bitterness at being unable to effectively serve the emperor.<ref name="crespigny 1050"/><ref name="xiao knechtges 398"/> Zhang retired from office in 138, and returned home to Nanyang.<ref name="xiao knechtges 398"/><ref name="neinhauser 212"/> There he composed a [[Return to the Field (rhapsody)|rhapsody]] rejoicing over the opportunity his retirement gave him to read and to play his [[lute]].<ref name="crespigny 1050"/><ref name="neinhauser 212"/> A few months after his return home, Zhang was appointed to serve under the Imperial Secretariat and traveled back to the capital. He died there in 139, while still in office. By the time of his death, Zhang had composed thirty-two written works on literature, philosophy, science, and mysticism.<ref name="crespigny 1051">Crespigny, 1051.</ref> He was buried in his hometown Xi'e, in Nanyang Commandery; his friend Cui Yuan composed the inscription for his tomb.<ref name="crespigny 1051"/><ref name="xiao knechtges 398"/>
  
 
==Literature and poetry==
 
==Literature and poetry==
 
{{see|Chinese literature}}
 
{{see|Chinese literature}}
[[Image:QueenMother.png|thumb|left|200px|An Eastern Han [[earthenware]] figurine of the [[Queen Mother of the West]]. Zhang fantasized about her in his "Rhapsody on Contemplating the Mystery" (思玄賦), yet the pleasures of the flesh and [[immortality]] that she could offer were not tempting enough to sway his heart which was set elsewhere.<ref>Loewe (2005), 37.</ref>]]
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[[Image:Earthenware architecture models, Eastern Han Dynasty, 4.JPG|thumb|200px|Eastern Han tomb models of watchtowers; the one on the left has crossbowmen in the top balcony. Zhang wrote that Western Han emperors were entertained by displays of [[archery]] from the balconies of towers along Chang'an's Kunming Lake.]]
While working for the central court, Zhang Heng had access to a variety of written materials located in the Archives of the Eastern Pavilion.<ref name="harper 262">Harper, 262.</ref> Zhang read many of the great works of history in his day and claimed he had found ten instances where the ''[[Records of the Grand Historian]]'' by [[Sima Qian]] (145–90&nbsp;BCE) and the ''[[Book of Han]]'' by [[Ban Gu]] (CE&nbsp;32–92) differed from other ancient texts that were available to him.<ref name="lu 57">Lu, 57.</ref><ref name="crespigny 1049"/> His account was preserved and recorded in the 5th&nbsp;century text of the ''[[Book of Later Han]]'' by [[Fan Ye (historian)|Fan Ye]] (398–445).<ref name="lu 57"/> His [[Rhapsody (music)|rhapsodies]] and other literary works displayed a deep knowledge of classic texts, [[Chinese philosophy]], and [[Twenty-Four Histories|histories]].<ref name="crespigny 1049"/> He also compiled a commentary on the ''Taixuan'' (太玄, "Great Mystery") by the [[Taoism|Daoist]] author [[Yang Xiong (author)|Yang Xiong]] (53&nbsp;BCE–CE&nbsp;18).<ref name="crespigny 1050"/><ref name="xiao knechtges 398"/><ref name="yan 127"/>
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[[Image:Gentlemen in conversation, Eastern Han Dynasty.jpg|thumb|right|200px|Eastern Han tomb painting of two men engrossed in conversation; Zhang's ''shelun'' or hypothetical discourse, involved a written dialogue between imaginary or real persons to demonstrate how one could lead an exemplary life]]
 
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While working for the central court, Zhang Heng had access to a variety of written materials located in the Archives of the Eastern Pavilion.<ref name="harper 262">Donald Harper, "Wang Yen-shou's Nightmare Poem," ''Harvard Journal of Asiatic Studies'' 47 (1) (1987): 239–283. 262.</ref> Zhang read many of the great works of history in his day and claimed he had found ten instances where the ''[[Records of the Grand Historian]]'' by [[Sima Qian]] (145–90 B.C.E.) and the ''[[Book of Han]]'' by [[Ban Gu]] (32 – 92 C.E.) differed from other ancient texts that were available to him.<ref name="lu 57">Zongli Lu, "Problems concerning the Authenticity of Shih chi 123 Reconsidered," ''Chinese Literature: Essays, Articles, Reviews (CLEAR)'' 17 (1995): 51–68, 57.</ref><ref name="crespigny 1049"/> His account was preserved and recorded in the 5th&nbsp;century text of the ''[[Book of Later Han]]'' by [[Fan Ye (historian)|Fan Ye]] (398–445).<ref name="lu 57"/> His [[Rhapsody (music)|rhapsodies]] and other literary works displayed a deep knowledge of classic texts, [[Chinese philosophy]], and [[Twenty-Four Histories|histories]].<ref name="crespigny 1049"/> He also compiled a commentary on the ''Taixuan'' (太玄, "Great Mystery") by the [[Daoism|Daoist]] author [[Yang Xiong (author)|Yang Xiong]] (53 B.C.E. – 18 C.E.).<ref name="crespigny 1050"/><ref name="xiao knechtges 398"/><ref name="yan 127"/>
[[Xiao Tong]] (501–531), a [[crown prince]] of the [[Liang Dynasty]] (502–557), immortalized several of Zhang's works in his anthology of literature, ''Wen xuan''. Zhang's rhapsodies (''[[fu (literature)|fu]]'' 賦) include "Western Metropolis Rhapsody" (西京賦), "Eastern Metropolis Rhapsody" (東京賦), "Southern Capital Rhapsody" (南都賦), "Rhapsody on Contemplating the Mystery" (思玄賦), and "[[Return to the Field (rhapsody)|Rhapsody on Returning to the Fields]]" (歸田賦).<ref name="lewis 184">Lewis, 184.</ref> The latter fuses [[Daoism|Daoist]] ideas with [[Confucianism]] and was a precursor to later Chinese metaphysical nature poetry, according to Liu Wu-chi.<ref name="liu 54">Liu, 54.</ref> A set of four short lyric poems (''[[shi (poetry)|shi]]'' 詩) entitled "Lyric Poems on Four Sorrows" (四愁詩), is also included with Zhang's preface. This set constitutes some of the earliest heptasyllabic ''shi'' [[Chinese poetry]] written.<ref name="neinhauser 212"/><ref name="mair 251">Mair, 251.</ref> While still in Luoyang, Zhang became inspired to write his "Western Metropolis Rhapsody" and "Eastern Metropolis Rhapsody," which were based on the "Rhapsody on the Two Capitals" by the historian Ban Gu.<ref name="crespigny 1049"/> Zhang's work was similar to Ban's, although the latter fully praised the contemporaneous Eastern Han regime while Zhang provided a warning that it could suffer the same fate as the Western Han if it too declined into a state of decadence and moral depravity.<ref name="crespigny 1049"/> These two works satirized and criticized what he saw as the excessive luxury of the upper classes.<ref name="neinhauser 211"/> Zhang's "Southern Capital Rhapsody" commemorated his home city of Nanyang, home of the restorer of the Han Dynasty, Guangwu.<ref name="crespigny 1049"/>
 
 
 
[[Image:Earthenware architecture models, Eastern Han Dynasty, 4.JPG|thumb|left|200px|Eastern Han tomb models of watchtowers; the one on the left has crossbowmen in the top balcony. Zhang wrote that Western Han emperors were entertained by displays of archery from the balconies of towers along Chang'an's Kunming Lake.]]
 
  
Zhang's long lyrical poems also revealed a great amount of information on urban layout and basic geography. His rhapsody "Sir Based-On-Nothing" provides details on terrain, palaces, hunting parks, markets, and prominent buildings of [[Chang'an]], the Western Han capital.<ref name="lewis 184"/><ref name="neinhauser 211"/> Exemplifying his attention to detail, his rhapsody on Nanyang described gardens filled with spring garlic, summer [[bamboo shoot]]s, autumn leeks, winter rape-turnips, [[perilla]], [[tetradium|evodia]], and purple ginger.<ref>Knechtges, 232.</ref> Zhang Heng's writing confirms the size of the imperial hunting park in the suburbs of Chang'an, as his estimate for the circumference of the park's encircling wall agrees with the historian Ban Gu's estimate of roughly 400&nbsp;''[[Li (unit)|li]]'' (one li in Han times was equal to 415.8&nbsp;m, or 1,364&nbsp;ft, making the circumference of the park wall 166,320&nbsp;m, or 545,600&nbsp;ft).<ref>Schafer (1968), 372 (footnote 2).</ref> Along with [[Sima Xiangru]] (179–117&nbsp;BCE), Zhang listed a variety of animals and hunting game inhabiting the park, which were divided in the northern and southern portions of the park according to where the animals had originally came from: [[Northern and southern China|northern or southern China]].<ref>Schafer, 329–330.</ref> Somewhat similar to the description of Sima Xiangru, Zhang described the Western Han emperors and their entourage enjoying boat outings, water plays, fishing, and displays of archery targeting birds and other animals with stringed arrows from the tops of [[:Image:Earthenware architecture models, Eastern Han Dynasty, 1.JPG|tall towers]] along Chang'an's Kunming Lake.<ref name="bulling 312">Bulling, 312 & 314.</ref> The focus of Zhang's writing on specific places and their terrain, society, people, and their customs could also be seen as early attempts of [[ethnographic]] categorization.<ref name="lewis 238">Lewis, 238.</ref> In his poem "Xijing fu," Zhang shows that he was aware of the new foreign religion of [[Buddhism]], introduced via the [[Silk Road]], as well as the legend of the birth of [[Gautama Buddha|Buddha]] with the vision of the [[white elephant]] bringing about conception.<ref>Wu (1986), 271–272.</ref> In his "Western Metropolis Rhapsody," Zhang described court entertainments such as ''juedi'', a form of theatrical wrestling accompanied by music in which participants butted heads with bull horn masks.<ref name="loewe 1990 142 144">Loewe (1990), 142–144.</ref>
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[[Xiao Tong]] (501–531), a [[crown prince]] of the [[Liang Dynasty]] (502–557), immortalized several of Zhang's works in his [[anthology]] of literature, ''Wen xuan.'' Zhang's rhapsodies (''[[fu (literature)|fu]]'' ) include "Western Metropolis Rhapsody" (西京賦), "Eastern Metropolis Rhapsody" (東京賦), "Southern Capital Rhapsody" (南都賦), "Rhapsody on Contemplating the Mystery" (思玄賦), and "[[Return to the Field (rhapsody)|Rhapsody on Returning to the Fields]]" (歸田賦).<ref name="lewis 184">Lewis, 184.</ref> The latter fuses [[Daoism|Daoist]] ideas with [[Confucianism]] and was a precursor to later Chinese metaphysical nature poetry, according to Liu Wu-chi.<ref name="liu 54">Wu-chi Liu. 1990. ''An Introduction to Chinese Literature.'' (Westport: Greenwood Press of Greenwood Publishing Group. ISBN 0313267030), 54.</ref> A set of four short lyric poems (''[[shi (poetry)|shi]]'' 詩) entitled "Lyric Poems on Four Sorrows" (四愁詩), is also included with Zhang's preface. This set constitutes some of the earliest heptasyllabic ''shi'' [[Chinese poetry]] written.<ref name="neinhauser 212"/><ref name="mair 251">Mair, 251.</ref> While still in Luoyang, Zhang became inspired to write his "Western Metropolis Rhapsody" and "Eastern Metropolis Rhapsody," which were based on the "Rhapsody on the Two Capitals" by the historian Ban Gu.<ref name="crespigny 1049"/>
  
[[Image:Gentlemen in conversation, Eastern Han Dynasty.jpg|thumb|right|250px|Eastern Han tomb painting of two men engrossed in conversation; Zhang's ''shelun'' or hypothetical discourse, involved a written dialogue between imaginary or real persons to demonstrate how one could lead an exemplary life]]
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With his ''Response [to Criticism] of my Idleness'' ''(Yingxian),'' Zhang was an early writer and proponent of the Chinese literary genre ''shelun,'' or hypothetical discourse. Authors of this genre created a written dialogue between themselves and an imaginary person (or a real person of their entourage or association); the latter poses questions to the author on how to lead a successful life.<ref name="declercq 1-4">Declercq, 1–4.</ref> He also used it as a means to criticize himself for failing to obtain high office, but coming to the conclusion that the true gentleman displays virtue instead of greed for power.<ref name="crespigny 1050"/> In this work, Dominik Declercq asserts that the person urging Zhang to advance his career in a time of government corruption most likely represented the eunuchs or [[Empress Liang Na]]'s (116–150) powerful relatives in the [[Liang (surname)|Liang clan]].<ref name="declercq 65"/> Declercq states that these two groups would have been "anxious to know whether this famous scholar could be lured over to their side," but Zhang flatly rejected such an alignment by declaring in this politically charged piece of literature that his gentlemanly quest for virtue trumped any desire of his for power.<ref>Declercq, 65–66.</ref>
With his ''Response [to Criticism] of my Idleness'' ''(Yingxian)'', Zhang was an early writer and proponent of the Chinese literary genre ''shelun'', or hypothetical discourse. Authors of this genre created a written dialogue between themselves and an imaginary person (or a real person of their entourage or association); the latter poses questions to the author on how to lead a successful life.<ref name="declercq 1-4">Declercq, 1–4.</ref> He also used it as a means to criticize himself for failing to obtain high office, but coming to the conclusion that the true gentleman displays virtue instead of greed for power.<ref name="crespigny 1050"/> In this work, Dominik Declercq asserts that the person urging Zhang to advance his career in a time of government corruption most likely represented the eunuchs or [[Empress Liang Na]]'s (116–150) powerful relatives in the [[Liang (surname)|Liang clan]].<ref name="declercq 65"/> Declercq states that these two groups would have been "anxious to know whether this famous scholar could be lured over to their side," but Zhang flatly rejected such an alignment by declaring in this politically charged piece of literature that his gentlemanly quest for virtue trumped any desire of his for power.<ref>Declercq, 65–66.</ref>
 
  
==Achievements in science and technology==  
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==Achievements in Science and Technology==  
 
===Astronomy and mathematics===
 
===Astronomy and mathematics===
 
{{see|Chinese astronomy|Chinese mathematics}}
 
{{see|Chinese astronomy|Chinese mathematics}}
[[Image:Su Song Star Map 2.JPG|thumb|right|225px|[[History of typography in East Asia|Printed]] star map of [[Su Song]] (1020–1101) showing the south polar projection]]
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[[Image:Su Song Star Map 2.JPG|thumb|right|200px|[[History of typography in East Asia|Printed]] star map of [[Su Song]] (1020–1101) showing the south polar projection]]
For centuries the Chinese approximated [[pi]] as 3; [[Liu Xin]] (d. CE&nbsp;23) made the first known Chinese attempt at a more accurate calculation of 3.154, but there is no record detailing the method he used to obtain this figure.<ref name="needham volume 3 99 100">Needham, Volume 3, 99–100.</ref><ref name="arndt haenel lischka 176"/> In his work around 130,<ref name="needham volume 3 100">Needham, Volume 3, 100.</ref> Zhang Heng compared the celestial circle to the diameter of the earth, proportioning the former as 736 and the latter as 232, thus calculating pi as 3.1724.<ref name="berggren borwein 27">Berggren, Borwein & Borwein, 27.</ref> In Zhang's day, the ratio 4:3 was given for the area of a square to the area of its inscribed circle and the volume of a cube and volume of the inscribed sphere should also be 4<sup>2</sup>:3<sup>2</sup>.<ref name="berggren borwein 27"/> In formula, with D as diameter and V as volume, D<sup>3</sup>:V = 16:9 or V=<math>\tfrac{9}{16}</math>D<sup>3</sup>; Zhang realized that the value for diameter in this formula was inaccurate, noting the discrepancy as the value taken for the ratio.<ref name="berggren borwein 27"/><ref name="arndt haenel lischka 176">Arndt, Haenel, Lischka, 176.</ref> Zhang then attempted to remedy this by amending the formula with an additional <math>\tfrac{1}{16}</math>D<sup>3</sup>, hence V=<math>\tfrac{9}{16}</math>D<sup>3</sup> + <math>\tfrac{1}{16}</math>D<sup>3</sup> = <math>\tfrac{5}{8}</math>D<sup>3</sup>.<ref name="berggren borwein 27"/> With the ratio of the [[volume]] of the cube to the inscribed sphere at 8:5, the implied ratio of the area of the square to the circle is √<span style = "text-decoration:overline">8</span>:√<span style = "text-decoration:overline">5</span>.<ref name="berggren borwein 27"/><ref name="arndt haenel lischka 177">Arndt, Haenel, Lischka, 177.</ref> From this formula, Zhang calculated pi as the [[square root]] of 10 (or approximately 3.162).<ref name="wilson 16">Wilson, 16.</ref><ref name="crespigny 1050"/><ref name="berggren borwein 27"/><ref name="yan 128">Yan, 128.</ref><ref name="arndt haenel lischka 177"/> In the 3rd&nbsp;century, [[Liu Hui]] made the calculation more accurate with his [[Liu Hui's π algorithm|π algorithm]], which allowed him to obtain the value 3.14159.<ref name="needham volume 3 100 101">Needham, Volume 3, 100–101.</ref> Later, [[Zu Chongzhi]] (429–500) [[Milü|approximated pi]] as <math>\tfrac{355}{113}</math> or 3.141592, the most accurate calculation for pi the ancient Chinese would achieve.<ref>Berggren, Borwein & Borwein, 20 & 24–26.</ref>
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For centuries the Chinese approximated [[pi]] as 3; [[Liu Xin]] (d. 23 C.E.) made the first known Chinese attempt at a more accurate calculation of 3.154, but there is no record detailing the method he used to obtain this figure.<ref name="needham volume 3 99 100">Needham, Volume 3, 99–100.</ref><ref name="arndt haenel lischka 176">Jörg Arndt and Christoph Haenel. 2001. ''Pi Unleashed,'' Translated by Catriona and David Lischka. (Berlin: Springer. ISBN 3540665722), 176. </ref>In his work around 130,<ref name="needham volume 3 100">Needham, Volume 3, 100.</ref> Zhang Heng compared the celestial circle to the diameter of the earth, proportioning the former as 736 and the latter as 232, thus calculating pi as 3.1724.<ref name="berggren borwein 27">Lennart  Berggren, Jonathan M. Borwein, and Peter B. Borwein. 2004. ''Pi: A Source Book.'' (New York: Springer. ISBN 0387205713), 27.</ref> In Zhang's day, the ratio 4:3 was given for the area of a square to the area of its inscribed circle and the volume of a cube and volume of the inscribed sphere should also be 4<sup>2</sup>:3<sup>2</sup>.<ref name="berggren borwein 27"/> In formula, with D as diameter and V as volume, D<sup>3</sup>:V = 16:9 or V=<math>\tfrac{9}{16}</math>D<sup>3</sup>; Zhang realized that the value for diameter in this formula was inaccurate, noting the discrepancy as the value taken for the ratio.<ref name="berggren borwein 27"/><ref name="arndt haenel lischka 176">Arndt, Haenel, Lischka, 176.</ref> Zhang then attempted to remedy this by amending the formula with an additional <math>\tfrac{1}{16}</math>D<sup>3</sup>, hence V=<math>\tfrac{9}{16}</math>D<sup>3</sup> + <math>\tfrac{1}{16}</math>D<sup>3</sup> = <math>\tfrac{5}{8}</math>D<sup>3</sup>.<ref name="berggren borwein 27"/> With the ratio of the [[volume]] of the cube to the inscribed sphere at 8:5, the implied ratio of the area of the square to the circle is √<span style = "text-decoration:overline">8</span>:√<span style = "text-decoration:overline">5</span>.<ref name="berggren borwein 27"/><ref name="arndt haenel lischka 177">Arndt, Haenel, Lischka, 177.</ref> From this formula, Zhang calculated pi as the [[square root]] of 10 (or approximately 3.162).<ref name="wilson 16">Wilson, 16.</ref><ref name="crespigny 1050"/><ref name="berggren borwein 27"/><ref name="yan 128">Yan, 128.</ref><ref name="arndt haenel lischka 177"/> In the 3rd&nbsp;century, [[Liu Hui]] made the calculation more accurate with his [[Liu Hui's π algorithm|π algorithm]], which allowed him to obtain the value 3.14159.<ref name="needham volume 3 100 101">Needham, Volume 3, 100–101.</ref> Later, [[Zu Chongzhi]] (429–500) [[Milü|approximated pi]] as <math>\tfrac{355}{113}</math> or 3.141592, the most accurate calculation for pi the ancient Chinese would achieve.<ref>Berggren, Borwein & Borwein, 20 & 24–26.</ref>
  
In his publication of CE&nbsp;120 called ''The Spiritual Constitution of the Universe'' (靈憲, ''Ling Xian''),<ref name="crespigny 1050"/> Zhang Heng theorized that the universe was like an egg "as round as a [[crossbow]] pellet" with the stars on the shell and the Earth as the central yolk.<ref name="huang 64"/><ref name="balchin 27"/> This universe theory is congruent with the [[geocentric model]] as opposed to the [[Heliocentrism|heliocentric model]]. Although the ancient [[Warring States Period|Warring States]] (403–221 B.C.E.) Chinese astronomers [[Shi Shen]] and [[Gan De]] had compiled the world's first [[star catalogue]] in the 4th&nbsp;century&nbsp;BCE, Zhang nonetheless catalogued 2,500 stars which he placed in a "brightly shining" category (the Chinese estimated the total to be 14,000), and he recognized 124&nbsp;constellations.<ref name="crespigny 1050"/><ref name="balchin 27">Balchin, 27.</ref> In comparison, this star catalogue featured many more stars than the 850 documented by the Greek astronomer [[Hipparchus]] (c. 190–c.120&nbsp;BCE) in his catalogue, and more than [[Ptolemy]] (CE&nbsp;83–161), who catalogued over 1,000.<ref name="jones 1">Jones, 1.</ref> Zhang supported the "radiating influence" theory to explain [[solar eclipse|solar]] and [[lunar eclipse|lunar]] eclipses, a theory which was opposed by [[Wang Chong]] (CE&nbsp;27–97).<ref name="needham volume 3 411 413">Needham, Volume 3, 411–413.</ref>
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In his publication of 120 C.E.called ''The Spiritual Constitution of the Universe'' (靈憲, ''Ling Xian''),<ref name="crespigny 1050"/> Zhang Heng theorized that the [[universe]] was like an egg "as round as a [[crossbow]] pellet" with the stars on the shell and the Earth as the central yolk.<ref name="huang 64">Ray Huang. 1997. ''China: A Macro History.'' (New York: An East Gate Book, M. E. Sharpe, Inc.), 64.</ref><ref name="balchin 27"/> This universe theory is congruent with the [[geocentric model]] as opposed to the [[Heliocentrism|heliocentric model]]. Although the ancient [[Warring States Period|Warring States]] (403–221 B.C.E.) Chinese astronomers [[Shi Shen]] and [[Gan De]] had compiled the world's first [[star catalogue]] in the fourth century B.C.E., Zhang nonetheless catalogued 2500 [[star]]s which he placed in a "brightly shining" category (the Chinese estimated the total to be 14,000), and he recognized 124 [[constellation]]s.<ref name="crespigny 1050"/><ref name="balchin 27">Balchin, 27.</ref> In comparison, this star catalogue featured many more stars than the 850 documented by the Greek astronomer [[Hipparchus]] (c. 190–c.120 B.C.E.) in his catalogue, and more than [[Ptolemy]] (83–161 C.E.), who catalogued over 1000.<ref name="jones 1">Kenneth Glyn Jones. 1991. ''Messier's Nebulae and Star Clusters.'' (Cambridge: Cambridge University Press. ISBN 0521370795), 1.</ref> Zhang supported the "radiating influence" theory to explain [[solar eclipse|solar]] and [[lunar eclipse|lunar]] eclipses, a theory which was opposed by [[Wang Chong]] (27–97 C.E.).<ref name="needham volume 3 411 413">Needham, Volume 3, 411–413.</ref>
  
 
===Extra tank for inflow clepsydra===
 
===Extra tank for inflow clepsydra===
[[Image:Guardians of Day and Night, Han Dynasty.jpg|thumb|right|Han Dynasty paintings on [[tile]]; being conscious of time, the Chinese believed in [[Chinese mythology|guardian spirits]] for the divisions of day and night, such as these two guardians here representing 11 pm to 1 am (left) and 5 am to 7 am (right)]]
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[[Image:Guardians of Day and Night, Han Dynasty.jpg|thumb|right|200px|Han Dynasty paintings on [[tile]]; being conscious of time, the Chinese believed in [[Chinese mythology|guardian spirits]] for the divisions of day and night, such as these two guardians here representing 11 <small>P.M.</small> to 1 <small>A.M.</small> (left) and 5 <small>A.M.</small> to 7 <small>A.M.</small> (right)]]
The outflow clepsydra was a timekeeping device used in China as long ago as the [[Shang Dynasty]] (c.&nbsp;1600–c.&nbsp;1050&nbsp;BCE), and certainly by the [[Zhou Dynasty]] (1122–256&nbsp;BCE).<ref name="needham volume 4 part 2 479">Needham, Volume 4, Part 2, 479.</ref> The inflow clepsydra with an indicator rod on a float had been known in China since the beginning of the Han Dynasty in 202&nbsp;BCE and had replaced the outflow type.<ref name="needham volume 4 part 2 479"/> The [[Han Chinese]] noted the problem with the falling [[pressure head]] in the reservoir, which slowed the timekeeping of the device as the inflow vessel was filled.<ref name="needham volume 4 part 2 479"/> Zhang Heng was the first to address this problem, indicated in his writings from 117, by adding an extra compensating tank between the reservoir and the inflow vessel.<ref name="needham volume 4 part 2 479 footnote e"/><ref name="crespigny 1050"/> Zhang also mounted two statuettes of a Chinese immortal and a heavenly guard on the top of the inflow clepsydra, the two of which would guide the indicator rod with their left hand and point out the graduations with their right.<ref name="needham volume 4 part 2 164">Needham, Volume 4, Part 2, 164.</ref> Joseph Needham states that this was perhaps the ancestor of all [[Striking clock|clock jacks that would later sound the hours]] found in mechanical clocks by the 8th century, but he notes that these figures did not actually move like clock jack figurines or sound the hours.<ref name="needham volume 4 part 2 164"/> Many additional compensation tanks were added to later clepsydras in the tradition of Zhang Heng. In 610 the [[Sui Dynasty]] (581–618) engineers Geng Xun and Yuwen Kai crafted an unequal-armed [[steelyard balance]] able to make seasonal adjustments in the pressure head of the compensating tank, so that it could control the rate of water flow for different lengths of day and night during the year.<ref name="needham volume 4 part 2 480">Needham, Volume 4, Part 2, 480.</ref> Zhang mentioned a "jade dragon's neck," which in later times meant a siphon.<ref name="needham volume 3 320">Needham, Volume 3, 320.</ref> He wrote of the floats and indicator-rods of the inflow clepsydra as follows:
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The outflow ''clepsydra'' was a timekeeping device used in China as long ago as the [[Shang Dynasty]] (c.&nbsp;1600–c.&nbsp;1050 B.C.E.), and certainly by the [[Zhou Dynasty]] (1122–256 B.C.E.).<ref name="needham volume 4 part 2 479">Joseph Needham. 1986. ''Science and Civilization in China: Volume 4, Physics and Physical Technology, Part 2: Mechanical Engineering.'' (Taipei: Caves Books, Ltd.), 479.</ref> The inflow clepsydra with an indicator rod on a float had been known in China since the beginning of the Han Dynasty in 202 B.C.E. and had replaced the outflow type.<ref name="needham volume 4 part 2 479"/> The [[Han Chinese]] noted the problem with the falling [[pressure head]] in the reservoir, which slowed the timekeeping of the device as the inflow vessel was filled.<ref name="needham volume 4 part 2 479">Needham, volume 4 part 2 479.</ref> Zhang Heng was the first to address this problem, indicated in his writings from 117, by adding an extra compensating tank between the reservoir and the inflow vessel.<ref name="needham volume 4 part 2 479"><ref name="crespigny 1050"/> Zhang also mounted two statuettes of a Chinese immortal and a heavenly guard on the top of the inflow clepsydra, the two of which would guide the indicator rod with their left hand and point out the graduations with their right.<ref name="needham volume 4 part 2 164">Needham, Volume 4, Part 2, 164.</ref> Joseph Needham states that this was perhaps the ancestor of all [[Striking clock|clock jacks that would later sound the hours]] found in mechanical clocks by the eighth century, but he notes that these figures did not actually move like clock jack figurines or sound the hours.<ref name="needham volume 4 part 2 164">Needham, volume 4 part 2 164.</ref> Many additional compensation tanks were added to later clepsydras in the tradition of Zhang Heng. In 610 the [[Sui Dynasty]] (581–618) engineers Geng Xun and Yuwen Kai crafted an unequal-armed [[steelyard balance]] able to make seasonal adjustments in the pressure head of the compensating tank, so that it could control the rate of water flow for different lengths of day and night during the year.<ref name="needham volume 4 part 2 480">Needham, Volume 4, Part 2, 480.</ref> Zhang mentioned a "jade dragon's neck," which in later times meant a siphon.<ref name="needham volume 3 320">Needham, Volume 3, 320.</ref>
 
 
<blockquote>Bronze vessels are made and placed one above the other at different levels; they are filled with pure water. Each has at the bottom a small opening in the form of a 'jade dragon's neck'. The water dripping (from above) enters two inflow receivers (alternately), the left one being for the night and the right one for the day. On the covers of each (inflow receiver) there are small cast statuettes in gilt bronze; the left (night) one is an immortal and the right (day) one is a policeman. These figures guide the indicator-rod (lit. arrow) with their left hands, and indicate the graduations on it with their right hands, thus giving the time.<ref name="needham volume 3 320"/></blockquote>
 
  
 
===Water-powered armillary sphere===
 
===Water-powered armillary sphere===
 
[[Image:Clock Tower from Su Song's Book.JPG|thumb|right|200px|The original diagram of [[Su Song]]'s (1020–1101) [[clock tower]], featuring an [[armillary sphere]] powered by a [[waterwheel]], [[escapement]] mechanism, and [[chain drive]]]]
 
[[Image:Clock Tower from Su Song's Book.JPG|thumb|right|200px|The original diagram of [[Su Song]]'s (1020–1101) [[clock tower]], featuring an [[armillary sphere]] powered by a [[waterwheel]], [[escapement]] mechanism, and [[chain drive]]]]
  
Zhang Heng is the first person known to have applied hydraulic [[motive power]] (ie. by employing a [[waterwheel]] and [[Water clock|clepsydra]]) to rotate an [[armillary sphere]], an astronomical instrument representing the [[celestial sphere]].<ref name="needham volume 4 part 2 30">Needham, Volume 4, Part 2, 30.</ref><ref name="morton 70">Morton, 70.</ref><ref name="loewe 1968 107">Loewe (1968), 107.</ref><ref name="temple 37">Temple, 37.</ref> The Greek astronomer [[Eratosthenes]] (276®C194&nbsp;BCE) invented the first armillary sphere in 255&nbsp;BCE. The Chinese armillary sphere was fully developed by 52&nbsp;BCE, with the astronomer Geng Shouchang's addition of a permanently fixed equatorial ring.<ref name="needham volume 3 343">Needham, Volume 3, 343.</ref> In 84&nbsp;CE the astronomers Fu An and Jia Kui added the ecliptic ring, and finally Zhang Heng added the horizon and meridian rings.<ref name="needham volume 3 343"/><ref name="crespigny 1050"/> Zhang described this invention in his written work of 125, ''Apparatus for Rotating an Armillary Sphere by Clepsydra Water''. The sphere itself was rotated by a turning waterwheel, which in turn was powered by the constant pressure head of water in the water clock tank.<ref name="temple 37"/> His water-powered armillary influenced the design of later Chinese water clocks and led to the discovery of the [[escapement]] mechanism by the 8th&nbsp;century.<ref name="needham volume 4 part 2 532"/>
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Zhang Heng is the first person known to have applied [[hydraulics|hydraulic]] [[motive power]] (i.e., by employing a [[waterwheel]] and [[Water clock|clepsydra]]) to rotate an [[armillary sphere]], an astronomical instrument representing the [[celestial sphere]].<ref name="needham volume 4 part 2 30">Needham, Volume 4, Part 2, 30.</ref><ref name="morton 70">W. Scott Morton and Charlton M. Lewis. 2005. ''China: Its History and Culture.'' (New York: McGraw-Hill, Inc.), 70.</ref><ref name="loewe 1968 107">Loewe, 1968, 107.</ref><ref name="temple 37">Temple, 37.</ref> The Greek astronomer [[Eratosthenes]] (276 - c. 194 B.C.E.) invented the first armillary sphere in 255 B.C.E. The Chinese armillary sphere was fully developed by 52 B.C.E., with the astronomer Geng Shouchang's addition of a permanently fixed equatorial ring.<ref name="needham volume 3 343">Needham, Volume 3, 343.</ref> In 84 C.E. the astronomers Fu An and Jia Kui added the ecliptic ring, and finally Zhang Heng added the horizon and meridian rings.<ref name="needham volume 3 343"/><ref name="crespigny 1050"/> Zhang described this invention in his written work of 125, ''Apparatus for Rotating an Armillary Sphere by Clepsydra Water.'' The sphere itself was rotated by a turning waterwheel, which in turn was powered by the constant pressure head of water in the water clock tank.<ref name="temple 37"/> His water-powered armillary influenced the design of later Chinese water clocks and led to the discovery of the [[escapement]] mechanism by the eighth century.<ref name="needham volume 4 part 2 532">Needham, volume 4 part 2 532.</ref>
  
Zhang Heng's water-powered armillary sphere had profound effects on Chinese astronomy and mechanical engineering in later generations. His model and its complex use of gears greatly influenced the water-powered instruments of later astronomers such as [[Yi Xing]] (683–727), [[Zhang Sixun]] (fl.&nbsp;10th&nbsp;century), [[Su Song]] (1020–1101), [[Guo Shoujing]] (1231–1316), and many others. Water-powered armillary spheres in the tradition of Zhang Heng's were used in the eras of the [[Three Kingdoms]] (220–280) and [[Jin Dynasty (265–420)|Jin Dynasty]] (265–420), yet the design for it was temporarily out of use between 317 and 418, due to invasions of northern [[Xiongnu]] nomads.<ref name="needham volume 4 part 2 483">Needham, Volume 4, Part 2, 483.</ref> Zhang Heng's old instruments were recovered in 418, when [[Emperor Wu of Liu Song]] (r.&nbsp;420–422) captured the ancient capital of Chang'an. Although still intact, the graduation marks and the representations of the stars, Moon, Sun, and planets were quite worn down by time and rust.<ref name="needham volume 4 part 2 483"/> In 436, the emperor ordered Qian Luozhi, the Secretary of the Bureau of Astronomy and Calendar, to recreate Zhang's device, which he managed to do successfully.<ref name="needham volume 4 part 2 483"/> Qian's water-powered celestial globe was still in use at the time of the Liang Dynasty (502–557), and successive models of water-powered armillary spheres were designed in subsequent dynasties.<ref name="needham volume 4 part 2 483"/>
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Zhang Heng's water-powered armillary sphere had profound effects on [[Chinese astronomy]] and [[mechanical engineering]] in later generations. His model and its complex use of gears greatly influenced the water-powered instruments of later astronomers such as [[Yi Xing]] (683–727), [[Zhang Sixun]] (fl. tenth century), [[Su Song]] (1020–1101), [[Guo Shoujing]] (1231–1316), and many others. Water-powered armillary spheres in the tradition of Zhang Heng's were used in the eras of the [[Three Kingdoms]] (220–280) and [[Jin Dynasty (265–420)|Jin Dynasty]] (265–420), yet the design for it was temporarily out of use between 317 and 418, due to invasions of northern [[Xiongnu]] [[nomad]]s.<ref name="needham volume 4 part 2 483">Needham, Volume 4, Part 2, 483.</ref> Zhang Heng's old instruments were recovered in 418, when [[Emperor Wu of Liu Song]] (r.&nbsp;420–422) captured the ancient capital of [[Chang'an]]. Although still intact, the graduation marks and the representations of the stars, Moon, Sun, and planets were quite worn down by time and rust.<ref name="needham volume 4 part 2 483"/> In 436, the emperor ordered Qian Luozhi, the Secretary of the Bureau of Astronomy and Calendar, to recreate Zhang's device, which he managed to do successfully.<ref name="needham volume 4 part 2 483"/> Qian's water-powered celestial [[globe]] was still in use at the time of the [[Liang Dynasty]] (502–557), and successive models of water-powered armillary spheres were designed in subsequent dynasties.<ref name="needham volume 4 part 2 483"/>
  
 
===Zhang's seismometer===
 
===Zhang's seismometer===
[[Image:EastHanSeismograph.JPG|thumbnail|right|250px|A replica of Zhang Heng's [[seismometer]], the ''Houfeng didong yi'', featured in the Chabot Space & Science Center in Oakland, California]]
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[[Image:EastHanSeismograph.JPG|thumbnail|right|200px|A replica of Zhang Heng's [[seismometer]], the ''Houfeng didong yi,'' featured in the Chabot Space & Science Center in Oakland, California. ]]
  
In 132, Zhang Heng presented to the Han court what many historians consider to be his most impressive invention, the first [[seismometer]]. It was named ''Houfeng didong yi'' (候风地动仪, lit. instrument for measuring the seasonal winds and the movements of the Earth), and it was able to determine the exact direction (out of eight directions) of tremors and earthquakes.<ref name="morton 70"/><ref name="crespigny 1050"/> According to the ''[[Book of Later Han]]'' (compiled by [[Fan Ye (historian)|Fan Ye]] in the 5th&nbsp;century), his copper urn-shaped device, with a swinging pendulum inside, was able to detect the direction of an earthquake hundreds of miles/kilometers away.<ref name="needham volume 4 part 2 484">Neehdam, Volume 4, Part 2, 484.</ref><ref name="loewe 1968 106">Loewe (1968), 106.</ref> This was essential for the Han government in sending quick aid and relief to regions devastated by this natural disaster.<ref>Needham, Volume 4, Part 2, 484; Needham, Volume 3, 632.</ref><ref name="wright 66"/><ref name="dillon 378"/> The device was considered important enough to be mentioned in the "Annals" chapter of the ''Book of Later Han'', detailing the reign of Emperor Shun.<ref name="needham volume 3 632">Needham, Volume 3, 632.</ref>
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In 132, Zhang Heng presented to the Han court what many historians consider to be his most impressive invention, the first [[seismometer]]. It was named ''Houfeng didong yi'' (候风地动仪, lit. instrument for measuring the seasonal winds and the movements of the Earth), and it was able to determine the exact direction (out of eight directions) of tremors and earthquakes.<ref name="morton 70"/><ref name="crespigny 1050"/> According to the ''[[Book of Later Han]]'' (compiled by [[Fan Ye (historian)|Fan Ye]] in the fifth century), his copper urn-shaped device, with a swinging [[pendulum]] inside, was able to detect the direction of an earthquake hundreds of miles/kilometers away.<ref name="needham volume 4 part 2 484">Neehdam, Volume 4, Part 2, 484.</ref><ref name="loewe 1968 106">Loewe, 1968, 106. </ref> This was essential for the Han government in sending quick aid and relief to regions devastated by this natural disaster.<ref>Needham, Volume 4, Part 2, 484; Needham, Volume 3, 632.</ref><ref name="wright 66">Wright, 66.</ref><ref name="dillon 378">Michael Dillon. 1998. ''China: A Historical and Cultural Dictionary.'' (Surrey: Routledge Curzon Press. ISBN 0700704396), 378. </ref>The device was considered important enough to be mentioned in the "Annals" chapter of the ''Book of Later Han,'' detailing the reign of Emperor Shun.<ref name="needham volume 3 632">Needham, Volume 3, 632.</ref>
  
 
To indicate the direction of a distant earthquake, Zhang's device dropped a bronze ball from one of eight tubed projections shaped as dragon heads; the ball fell into the mouth of a corresponding metal object shaped as a toad, each representing a direction like the points on a [[compass rose]].<ref>Needham, Volume 3, 627–628.</ref> His device had eight mobile arms (for all eight directions) connected with cranks having catch mechanisms at the periphery.<ref name="needham volume 3 629"/> When tripped, a crank and right angle lever would raise a dragon head and release a ball which had been supported by the lower jaw of the dragon head.<ref name="needham volume 3 629"/> His device also included a vertical pin passing through a slot in the crank, a catch device, a pivot on a projection, a sling suspending the pendulum, an attachment for the sling, and a horizontal bar supporting the pendulum.<ref name="needham volume 3 629">Needham, Volume 3, 629.</ref> Wang Zhenduo (王振铎) argued that the technology of the Eastern Han era was sophisticated enough to produce such a device, as evidenced by contemporary levers and cranks used in other devices such as crossbow triggers.<ref name="needham volume 3 630">Needham, Volume 3, 630.</ref>
 
To indicate the direction of a distant earthquake, Zhang's device dropped a bronze ball from one of eight tubed projections shaped as dragon heads; the ball fell into the mouth of a corresponding metal object shaped as a toad, each representing a direction like the points on a [[compass rose]].<ref>Needham, Volume 3, 627–628.</ref> His device had eight mobile arms (for all eight directions) connected with cranks having catch mechanisms at the periphery.<ref name="needham volume 3 629"/> When tripped, a crank and right angle lever would raise a dragon head and release a ball which had been supported by the lower jaw of the dragon head.<ref name="needham volume 3 629"/> His device also included a vertical pin passing through a slot in the crank, a catch device, a pivot on a projection, a sling suspending the pendulum, an attachment for the sling, and a horizontal bar supporting the pendulum.<ref name="needham volume 3 629">Needham, Volume 3, 629.</ref> Wang Zhenduo (王振铎) argued that the technology of the Eastern Han era was sophisticated enough to produce such a device, as evidenced by contemporary levers and cranks used in other devices such as crossbow triggers.<ref name="needham volume 3 630">Needham, Volume 3, 630.</ref>
  
 
===Cartography===
 
===Cartography===
[[Image:Song Dynasty Map.JPG|thumb|right|200px|The ''Yu Ji Tu'', or ''Map of the Tracks of Yu Gong'', carved into stone in 1137, located in the [[Stele Forest]] of [[Xi'an]]. This {{convert|3|ft|m|abbr=on}} squared map features a [[Scale (map)|graduated scale]] of 100 ''[[Li (unit)|li]]'' for each rectangular grid. Although [[Pei Xiu]] is credited with the first description of graduated scale and [[grid reference]]s for maps, there is evidence that Zhang Heng was the innovator.]]
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[[Image:Song Dynasty Map.JPG|thumb|right|200px|The ''Yu Ji Tu,'' or ''Map of the Tracks of Yu Gong,'' carved into stone in 1137, located in the [[Stele Forest]] of [[Xi'an]]. This {{convert|3|ft|m|abbr=on}} squared map features a [[Scale (map)|graduated scale]] of 100 ''[[Li (unit)|li]]'' for each rectangular grid. Although [[Pei Xiu]] is credited with the first description of graduated scale and [[grid reference]]s for maps, there is evidence that Zhang Heng was the innovator.]]
  
The [[Cao Wei|Wei]] (220–265) and [[Jin Dynasty (265-420)|Jin Dynasty]] (265–420) [[History of cartography#China|cartographer]] and official [[Pei Xiu]] (224–271) was the first in China to describe in full the geometric [[grid reference]] for maps that allowed for precise measurements [[Scale (map)|using a graduated scale]], as well as topographical [[elevation]].<ref>Needham, Volume 3, 538–540.</ref><ref name="hsu 97">Hsu, 97.</ref> However, map-making in China had existed since at least the 4th&nbsp;century&nbsp;BCE with the [[Qin (state)|Qin state]] maps found in [[Gansu]] in 1986.<ref>Hsu, 90.</ref> Pinpointed accuracy of the winding courses of rivers and familiarity with scaled distance had been known since the [[Qin Dynasty|Qin]] and Han Dynasty, respectively, as evidenced by their existing maps, while the use of a rectangular [[grid]] had been known in China since the Han as well.<ref name="needham volume 3 106 107">Needham, Volume 3, 106–107.</ref><ref name="hsu 90 97">Hsu, 90 & 97.</ref> Historian Howard Nelson states that, although the accounts of Zhang Heng's work in cartography are somewhat vague and sketchy, there is ample written evidence that Pei Xiu derived the use of the rectangular grid reference from the maps of Zhang Heng.<ref name="nelson 359">Nelson, 359.</ref> Rafe de Crespigny asserts that it was Zhang who established the rectangular grid system in Chinese cartography.<ref name="crespigny 1050"/> Robert Temple writes that Zhang not only presented a map to the emperor in 116 C.E., but his now lost works called ''Discourse on New Calculations'' and ''Bird's-Eye Map'' "laid the groundwork for the mathematical use of the grid with maps."<ref name="temple 30">Temple (1986), 30.</ref> Moreover, the ''[[Book of Later Han]]'' hints that Zhang was the first to make a mathematical grid reference, stating that he "cast a network of coordinates about heaven and earth, and reckoned on the basis of it."<ref name="temple 30"/> Historian Florian C. Reiter notes that Zhang's narrative "Guitian fu" contains a phrase about applauding the maps and documents of [[Confucius]] of the Zhou Dynasty, which Reiter suggests places maps ''(tu)'' on a same level of importance with documents ''(shu)''.<ref>Reiter, 320.</ref>
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The [[Cao Wei|Wei]] (220–265) and [[Jin Dynasty (265-420)|Jin Dynasty]] (265–420) [[History of cartography#China|cartographer]] and official [[Pei Xiu]] (224–271) was the first in China to describe in full the geometric [[grid reference]] for maps that allowed for precise measurements [[Scale (map)|using a graduated scale]], as well as topographical [[elevation]].<ref>Needham, Volume 3, 538–540.</ref><ref name="hsu 97">Mei-ling Hsu, "The Qin Maps: A Clue to Later Chinese Cartographic Development," ''Imago Mundi'' 45 (1993): 90–100, 97.</ref> However, map-making in China had existed since at least the fourth century B.C.E. with the [[Qin (state)|Qin state]] maps found in [[Gansu]] in 1986.<ref>Hsu, 90.</ref> Pinpointed accuracy of the winding courses of [[river]]s and familiarity with scaled distance had been known since the [[Qin Dynasty|Qin]] and Han Dynasty, respectively, as evidenced by their existing maps, while the use of a rectangular [[grid]] had been known in China since the Han as well.<ref name="needham volume 3 106 107">Needham, Volume 3, 106–107.</ref><ref name="hsu 90 97">Hsu, 90 & 97.</ref> Historian Howard Nelson states that, although the accounts of Zhang Heng's work in cartography are somewhat vague and sketchy, there is ample written evidence that Pei Xiu derived the use of the rectangular grid reference from the maps of Zhang Heng.<ref name="nelson 359">Nelson, 359.</ref> Rafe de Crespigny asserts that it was Zhang who established the rectangular grid system in Chinese cartography.<ref name="crespigny 1050"/> Robert Temple writes that Zhang not only presented a map to the emperor in 116 C.E., but his now lost works called ''Discourse on New Calculations'' and ''Bird's-Eye Map'' "laid the groundwork for the mathematical use of the grid with maps."<ref name="temple 30">Robert Temple. 1986. ''The Genius of China: 3,000 Years of Science, Discovery, and Invention,'' With a forward by Joseph Needham. (New York: Simon and Schuster, Inc. ISBN 0671620282), 30.</ref> Moreover, the ''[[Book of Later Han]]'' hints that Zhang was the first to make a mathematical grid reference, stating that he "cast a network of coordinates about heaven and earth, and reckoned on the basis of it."<ref name="temple 30"/> Historian Florian C. Reiter notes that Zhang's narrative "Guitian fu" contains a phrase about applauding the maps and documents of [[Confucius]] of the Zhou Dynasty, which Reiter suggests places maps ''(tu)'' on a same level of importance with documents ''(shu).''<ref>Florian C. Reiter, "Some Remarks on the Chinese Word t'u 'Chart, Plan, Design'," ''Oriens'' 32 (1990): 308–327. 320.</ref>
  
 
===Odometer and South Pointing Chariot===
 
===Odometer and South Pointing Chariot===
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[[Image:Han dynasty odometer cart.jpg|thumb|200px|left|[[Odometer]] cart from a stone rubbing of an Eastern Han Dynasty tomb, c. 125]]
 
Zhang Heng is often credited with inventing the first [[odometer]],<ref name="balchin 27"/><ref name="yan 128"/> an achievement also attributed to [[Archimedes]] (c.&nbsp;287–212&nbsp;BCE) and [[Heron of Alexandria]] (fl.&nbsp;CE&nbsp;10–70). Similar devices were used by the [[Ancient Rome|Roman]] and Han-Chinese empires at about the same period. By the 3rd&nbsp;century, the Chinese had termed the device the ''ji li gu che'', or "[[li (unit)|li]]-recording drum carriage" (the modern measurement of li&nbsp;=&nbsp;500&nbsp;m/1640&nbsp;ft).<ref name="needham volume 4 281">Needham, Volume 4, 281.</ref>
 
Zhang Heng is often credited with inventing the first [[odometer]],<ref name="balchin 27"/><ref name="yan 128"/> an achievement also attributed to [[Archimedes]] (c.&nbsp;287–212&nbsp;BCE) and [[Heron of Alexandria]] (fl.&nbsp;CE&nbsp;10–70). Similar devices were used by the [[Ancient Rome|Roman]] and Han-Chinese empires at about the same period. By the 3rd&nbsp;century, the Chinese had termed the device the ''ji li gu che'', or "[[li (unit)|li]]-recording drum carriage" (the modern measurement of li&nbsp;=&nbsp;500&nbsp;m/1640&nbsp;ft).<ref name="needham volume 4 281">Needham, Volume 4, 281.</ref>
  
[[Image:Han dynasty odometer cart.jpg|thumb|200px|left|[[Odometer]] cart from a stone rubbing of an Eastern Han Dynasty tomb, c. 125]]
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The [[South Pointing Chariot]] was another mechanical device credited to Zhang Heng.<ref name="yan 128"/> It was a non-magnetic compass vehicle in the form of a two-wheeled chariot. [[differential (mechanical device)|Differential gears]] driven by the chariot's wheels allowed a wooden figurine (in the shape of a Chinese state minister) to constantly point to the south, hence its name. The ''Song Shu'' (c.&nbsp;500&nbsp;CE) records that Zhang Heng re-invented it from a model used in the Zhou Dynasty era, but the violent collapse of the Han Dynasty unfortunately did not allow it to be preserved. Whether Zhang Heng invented it or not, [[Ma Jun]] (200–265) succeeded in creating the chariot in the following century.<ref name="needham volume 4 part 2 40">Needham, Volume 4, Part 2, 40.</ref>
Ancient Chinese texts describe the mechanical carriage's functions; after one li was traversed, a mechanically driven wooden figure struck a drum, and after ten li had been covered, another wooden figure struck a gong or a bell with its mechanically operated arm.<ref name="needham volume 4 281"/> However, there is evidence to suggest that the invention of the odometer was a gradual process in Han Dynasty China that centered around the "huang men"—court people (ie. eunuchs, palace officials, attendants and familiars, actors, acrobats, etc.) who followed the musical procession of the royal "drum-chariot".<ref name="needham volume 4 283">Needham, Volume 4, 283.</ref> There is speculation that at some time during the 1st&nbsp;century&nbsp;BCE the beating of drums and gongs was mechanically driven by the rotation of the road wheels.<ref name="needham volume 4 283"/> This might have actually been the design of [[Luoxia Hong]] (c.&nbsp;110&nbsp;BCE), yet by at least 125 the mechanical odometer carriage was already known, as it was depicted in a mural of the Xiao Tang Shan Tomb.<ref name="needham volume 4 283"/>
 
 
 
The [[South Pointing Chariot]] was another mechanical device credited to Zhang Heng.<ref name="yan 128"/> It was a non-magnetic compass   vehicle in the form of a two-wheeled chariot. [[differential (mechanical device)|Differential gears]] driven by the chariot's wheels allowed a wooden figurine (in the shape of a Chinese state minister) to constantly point to the south, hence its name. The ''Song Shu'' (c.&nbsp;500&nbsp;CE) records that Zhang Heng re-invented it from a model used in the Zhou Dynasty era, but the violent collapse of the Han Dynasty unfortunately did not allow it to be preserved. Whether Zhang Heng invented it or not, [[Ma Jun]] (200–265) succeeded in creating the chariot in the following century.<ref name="needham volume 4 part 2 40">Needham, Volume 4, Part 2, 40.</ref>
 
  
 
==Legacy==
 
==Legacy==
 
===Science and technology===
 
===Science and technology===
[[Image:Astrology della Robbia OPA Florence.jpg|thumb|right|200px|A [[Florence|Florentine]] marble carving of [[Ptolemy]] (86–161), who created an Earth-centered universe theory that the scholars Jin Guantao, Fan Hongye, and Liu Qingfeng compare with Zhang Heng's theory published in 125<ref name="jin fan liu 170"/>]]
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[[Image:Astrology della Robbia OPA Florence.jpg|thumb|right|200px|A [[Florence|Florentine]] marble carving of [[Ptolemy]] (86–161), who created an Earth-centered universe theory that the scholars Jin Guantao, Fan Hongye, and Liu Qingfeng compare with Zhang Heng's theory published in 125<ref name="jin fan liu 170">Guantao Jin, Fan Hongye, and Liu Qingfeng. 1996. "Historical Changes in the Structure of Science and Technology (Part Two, a Commentary)" in ''Chinese Studies in the History and Philosophy of Science and Technology,'' 165–184, edited by Fan Dainian and Robert S. Cohen, translated by Kathleen Dugan and Jiang Mingshan. (Dordrecht: Kluwer Academic Publishers. ISBN 0792334639). </ref>]]
  
Zhang Heng's mechanical inventions influenced later Chinese inventors such as Yi Xing, Zhang Sixun, Su Song, and Guo Shoujing. Su Song directly named Zhang's water-powered armillary sphere as the inspiration for his 11th-century [[clock tower]].<ref name="needham volume 4 part 2 466">Needham, Volume 4, Part 2, 466.</ref> The cosmic model of nine points of Heaven corresponding with nine regions of earth conceived in the work of the scholar-official [[Chen Hongmou]] (1696–1771) followed in the tradition of Zhang's book ''Spiritual Constitution of the Universe''.<ref name="rowe 88">Rowe, 88.</ref> The seismologist John Milne, who created the modern seismograph in 1876 alongside Thomas Gray and [[James Alfred Ewing|James A. Ewing]] at the [[Imperial College of Engineering]] in [[Tokyo]], commented in 1886 on Zhang Heng's contributions to [[seismology]].<ref name="yan 124">Yan, 124.</ref><ref name="needham volume 3 626">Needham, Volume 3, 626.</ref> The historian Joseph Needham emphasized his contributions to pre-modern Chinese technology, stating that Zhang was noted even in his day for being able to "make three wheels rotate as if they were one."<ref name="needham volume 4 85">Needham, Volume 4, 85–86.</ref> More than one scholar has described Zhang as a [[polymath]].<ref name="mair 251"/><ref name="yan 127"/><ref name="dillon 378">Dillon, 378.</ref><ref name="krebs 31">Krebs, 31.</ref> However, some scholars also point out that Zhang's writing lacks concrete scientific theories.<ref name="jin fan liu 170">Jin, Fan, and Liu, 170.</ref>
+
Zhang Heng's mechanical inventions influenced later Chinese inventors such as Yi Xing, Zhang Sixun, Su Song, and Guo Shoujing. Su Song directly named Zhang's water-powered armillary sphere as the inspiration for his eleventh-century [[clock tower]].<ref name="needham volume 4 part 2 466">Needham, Volume 4, Part 2, 466.</ref> The cosmic model of nine points of Heaven corresponding with nine regions of earth conceived in the work of the scholar-official [[Chen Hongmou]] (1696–1771) followed in the tradition of Zhang's book ''Spiritual Constitution of the Universe.'' <ref name="rowe 88">William T. Rowe. 2001. ''Saving the World: Chen Hongmou and Elite Consciousness in Eighteenth-Century China.'' (Stanford: Stanford University Press. ISBN 0804748187), 88.</ref> The [[seismology|seismologist]] John Milne, who created the modern seismograph in 1876 alongside Thomas Gray and [[James Alfred Ewing|James A. Ewing]] at the [[Imperial College of Engineering]] in [[Tokyo]], commented in 1886 on Zhang Heng's contributions to seismology.<ref name="yan 124">Yan, 124.</ref><ref name="needham volume 3 626">Needham, Volume 3, 626.</ref> The historian Joseph Needham emphasized his contributions to pre-modern Chinese technology, stating that Zhang was noted even in his day for being able to "make three wheels rotate as if they were one."<ref name="needham volume 4 85">Needham, Volume 4, 85–86.</ref> More than one scholar has described Zhang as a [[polymath]].<ref name="mair 251">Victor H. Mair. 2001. ''The Columbia History of Chinese Literature.'' (New York: Columbia University Press. ISBN 0231109849), 251. </ref><ref name="yan 127"/><ref name="dillon 378">Dillon, 378.</ref><ref name="krebs 31">Krebs, 31.</ref> However, some scholars also point out that Zhang's writing lacks concrete scientific theories.<ref name="jin fan liu 170">Jin, Fan, and Liu, 170.</ref>
  
 
===Poetic literature===
 
===Poetic literature===
Zhang's poetry was widely read during his life and after his death. In addition to the compilation of Xiao Tong mentioned above, the [[Eastern Wu]] official [[Xue Zong]] (d. 237) wrote commentary on Zhang's poems "Dongjing fu" and "Xijing fu".<ref>Cutter, 11 (footnote 61), 15, (footnote 80), 26 (footnote 141).</ref> The influential poet Tao Qian wrote that he admired the poetry of Zhang Heng for its "curbing extravagant diction and aiming at simplicity," in regards to perceived tranquility and rectitude correlating with the simple but effective language of the poet.<ref>Yim-tze, 63.</ref> Tao wrote that both Zhang Heng and Cai Yong "avoided inflated language, aiming chiefly at simplicity," and adding that their "compositions begin by giving free expression to their fancies but end on a note of quiet, serving admirably to restrain undisciplined and passionate nature".<ref name="hightower 169 170">Hightower, 169–170.</ref>
+
Zhang's poetry was widely read during his life and after his death. In addition to the compilation of Xiao Tong mentioned above, the [[Eastern Wu]] official [[Xue Zong]] (d. 237) wrote commentary on Zhang's poems "Dongjing fu" and "Xijing fu".<ref>Robert Joe Cutter, "Cao Zhi's (192-232) Symposium Poems," ''Chinese Literature: Essays, Articles, Reviews (CLEAR)'' 6 (1/2) (1984): 1–32, 11 (footnote 61), 15, (footnote 80), 26 (footnote 141).</ref> The influential poet Tao Qian wrote that he admired the poetry of Zhang Heng for its "curbing extravagant diction and aiming at simplicity," in regards to perceived tranquility and rectitude correlating with the simple but effective language of the poet.<ref>Kwong Yim-tze, "Naturalness and Authenticity: The Poetry of Tao Qian," ''Chinese Literature: Essays, Articles, Reviews (CLEAR)'' 11 (1989): 35–77, 63.</ref> Tao wrote that both Zhang Heng and Cai Yong "avoided inflated language, aiming chiefly at simplicity," and adding that their "compositions begin by giving free expression to their fancies but end on a note of quiet, serving admirably to restrain undisciplined and passionate nature".<ref name="hightower 169 170">James Robert Hightower, "The Fu of T'ao Ch'ien," ''Harvard Journal of Asiatic Studies'' 17 (1/2) (1954): 169–230, 169–170.</ref>
  
 
===Posthumous honors===
 
===Posthumous honors===
 
Zhang was given great honors in life and in death. The philosopher and poet [[Fu Xuan]] (217–278) of the [[Cao Wei|Wei]] and [[Jin Dynasty (265–420)|Jin]] dynasties once lamented in an essay over the fact that Zhang Heng was never placed in the [[Nine Ministers|Ministry of Works]]. Writing highly of Zhang and the 3rd-century mechanical engineer Ma Jun, Fu Xuan wrote, "Neither of them was ever an official of the Ministry of Works, and their ingenuity did not benefit the world. When (authorities) employ personnel with no regard to special talent, and having heard of genius neglect even to test it—is this not hateful and disastrous?"<ref name="needham volume 4 42">Needham, Volume 4, 42.</ref>
 
Zhang was given great honors in life and in death. The philosopher and poet [[Fu Xuan]] (217–278) of the [[Cao Wei|Wei]] and [[Jin Dynasty (265–420)|Jin]] dynasties once lamented in an essay over the fact that Zhang Heng was never placed in the [[Nine Ministers|Ministry of Works]]. Writing highly of Zhang and the 3rd-century mechanical engineer Ma Jun, Fu Xuan wrote, "Neither of them was ever an official of the Ministry of Works, and their ingenuity did not benefit the world. When (authorities) employ personnel with no regard to special talent, and having heard of genius neglect even to test it—is this not hateful and disastrous?"<ref name="needham volume 4 42">Needham, Volume 4, 42.</ref>
  
In honor of Zhang's achievements in science and technology, his friend Cui Ziyu (Cui Yuan) wrote a memorial inscription on his burial stele, which has been preserved in the ''Guwen yuan''.<ref name="xiao knechtges 398">Xiao & Knechtges, 398.</ref> Cui stated, "[Zhang Heng's] mathematical computations exhausted (the riddles of) the heavens and the earth. His inventions were comparable even to those of the Author of Change. The excellence of his talent and the splendour of his art were one with those of the gods."<ref name="needham volume 3 359">Needham, Volume 3, 359.</ref> The minor official Xiahou Zhan (243–291) of the Wei Dynasty made an inscription for his own commemorative stele to be placed at Zhang Heng's tomb. It read: "Ever since gentlemen have composed literary texts, none has been as skillful as the Master [Zhang Heng] in choosing his words well&nbsp;...&nbsp;if only the dead could rise, oh I could then turn to him for a teacher!"<ref name="declercq 247">Declercq, 247.</ref>
+
In honor of Zhang's achievements in science and technology, his friend Cui Ziyu (Cui Yuan) wrote a memorial inscription on his burial stele, which has been preserved in the ''Guwen yuan''.<ref name="xiao knechtges 398">Xiao & Knechtges, 398.</ref> Cui stated, "[Zhang Heng's] mathematical computations exhausted (the riddles of) the heavens and the earth. His inventions were comparable even to those of the Author of Change. The excellence of his talent and the splendour of his art were one with those of the gods."<ref name="needham volume 3 359">Needham, Volume 3, 359.</ref> The minor official Xiahou Zhan (243–291) of the Wei Dynasty made an inscription for his own commemorative stele to be placed at Zhang Heng's tomb. It read: "Ever since gentlemen have composed literary texts, none has been as skillful as the Master [Zhang Heng] in choosing his words well&nbsp;...&nbsp;if only the dead could rise, oh I could then turn to him for a teacher!"<ref name="declercq 247">Dominik Declercq. 1998. ''Writings Against the State: Political Rhetorics in Third and Fourth Century China.'' (Leiden: Koninklijke Brill NV.), 247.</ref>
  
Several things have been named after Zhang in modern times, including the lunar crater [[Chang Heng (crater)|Chang Heng]],<ref>''Lunar Names Proposed'', 290.</ref> the asteroid [[1802 Zhang Heng]],<ref name="schmadel 144">Schmadel, 144.</ref> and the mineral [[Zhanghengite]].
+
Several things have been named after Zhang in modern times, including the lunar crater [[Chang Heng (crater)|Chang Heng]],<ref>"Lunar Names Proposed," ''Science News'' 90 (16) (1966): 290. </ref> the asteroid [[1802 Zhang Heng]],<ref name="schmadel 144">Lutz D. Schmadel. 2003. ''Dictionary of Minor Planet Names: Fifth Revised and Enlarged Edition.'' (New York: Springer. ISBN 3540002383), 144.</ref> and the [[mineral]] [[Zhanghengite]].
  
 
==Notes==
 
==Notes==
Line 128: Line 114:
  
 
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</div>
 
  
 
==External links==
 
==External links==
All links are retrieved January 26, 2009.
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All links retrieved October 16, 2020.
{{Commons|Zhang Heng}}
+
 
*[http://www.chinaculture.org/gb/en_madeinchina/2005-08/18/content_71970.htm Zhang Heng at Chinaculture.org]
 
*[http://hua.umf.maine.edu/China/astronomy/tianpage/0012ZhangHeng6539w.html Zhang Heng at the University of Maine, USA]
 
 
*[http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Zhang_Heng.html Zhang Heng at the University of St Andrews, Scotland]
 
*[http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Zhang_Heng.html Zhang Heng at the University of St Andrews, Scotland]
*[http://earthquake.usgs.gov/learning/topics/seismology/history/part04.php The Early History of Seismology (to 1900)]
 
  
{{featured article}}
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[[Category:literature]]
 
[[Category:literature]]

Revision as of 00:39, 17 April 2023


Zhang Heng (張衡)

Zhang Heng.jpg
Born

78
Nanyang, China

Died 139

Luoyang, China

Residence Nanyang, Luoyang
Field Astronomy, mathematics, seismology, hydraulics, geography, ethnography, mechanical engineering, calendrical science, metaphysics, poetry
Known for Seismometer, hydraulic-powered armillary sphere, pi calculation, shi, universe model, lunar eclipse and solar eclipse theory
Religious stance Daoism, Chinese folk religion

Zhang Heng (Traditional Chinese: 張衡; Simplified Chinese: 张衡; Hanyu Pinyin: Zhāng Héng; Wade-Giles: Chang Heng) (CE 78–139) was a Chinese polymath, being a astronomer, mathematician, inventor, geographer, cartographer, artist, poet, statesman, and literary scholar. He was from Nanyang, Henan, and lived during the Eastern Han Dynasty (25 – 220 C.E.).

Zhang made numerous contributions which gave lasting influences on the development of intellectual, technological, and literary traditions of China. Among his many accomplishments, Zhang is credited with inventing a seismometer. His device was able to determine the cardinal direction of earthquakes. Zhang Heng is also the first person to have applied hydraulic motive power to rotate an armillary sphere, an astronomical instrument representing the celestial sphere.

As an astronomer, Zhang cataloged 2500 stars, and recognized 124 distinct constellations, exceeding Hipparchus (c. 190 - c.120 B.C.E.) or Ptolemy (83-161 C.E.) who cataloged more than 1000. Zhang also invented the first odometer, often referenced as Archimedes (c. 287 - 212 B.C.E.). As a cartographer, Zhang was the first to make a mathematical grid reference.

Zhang was one of the best known writers in literature and poetry in the Eastern Han Dynasty. He wrote science fiction, cosmological, ethnographic literature, and started a new poetic style. He was also numbered as one of six best artists in the Eastern Han. In his poetry Zhang often expressed his moral criticism against decadent, lavish life styles of politicians of his time.

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Life of Zhang Heng

Early life

A second-century lacquer-painted scene on a basket box showing famous figures from Chinese history who were paragons of filial piety; Zhang Heng became well-versed at an early age in the Chinese classics and the philosophy of China's earlier sages.

Born in the town of Xi'e in Nanyang Commandery (located north of modern Nanyang City, Henan province), Zhang Heng came from a distinguished but not very affluent family.[1]Rafe de Crespigny. 2007. A Biographical Dictionary of Later Han to the Three Kingdoms (23-220 C.E.). (Leiden: Koninklijke Brill. ISBN 9004156054), 1049.</ref>[2][3] His grandfather, Zhang Kan, had been governor of a commandery, and one of the leaders who supported the restoration of the Han Dynasty by Emperor Guangwu (r. 25–57), following the death of the usurper Wang Mang and his short-lived Xin Dynasty (9–23 C.E.).[1][4][5][6] At age ten, Zhang's father died, leaving him in the care of his mother and grandmother.[5] An accomplished writer in his youth, Zhang left home in 95 to pursue his studies at universities in the ancient capitals of Chang'an and Luoyang.[1] While traveling to Luoyang, Zhang passed by a hot spring near Mount Li and dedicated one of his earliest fu poems to it, the Wenquan (溫泉).[7] After studying for some years at Luoyang's Imperial University (Taixue), he became well-versed in the classics, and befriended notable persons, such as the mathematician and calligrapher Cui Yuan (78 – 143), the official and philosophical commentator Ma Rong (79 – 166), and the philosopher Wang Fu (78 – 163).[1][3] Government authorities offered Zhang appointments to several offices, including a position as one of the Three Excellencies, yet he acted modestly and turned down those positions.[1][7] At age 23, he returned home with the title "Officer of Merit in Nanyang," serving as the master of documents under the administration of Governor Bao De (in office from 103–111).[1][4][3] As he was charged with composing inscriptions and dirges for Bao De, he gained experience in writing official documents.[4] As Officer of Merit in the commandery, he was also responsible for local appointments to office and recommendations to the capital of nominees for higher office.[8] He spent much of his time composing rhapsodies on the capital cities. When Bao De was recalled to the capital in the year 111, to serve as a minister of finance, Zhang continued his literary work at home in Xi'e.[1][4][7] Zhang Heng began his studies in astronomy at the age of 30, and began publishing his works in astronomy and mathematics.[4]

Official career

In 112, Zhang was summoned to the court of Emperor An of Han (r.106 c. 125), who had heard of Zhang's expertise in mathematics.[4] When he was nominated to serve at the capital, Zhang was escorted by carriage (a symbol of his official status) to Luoyang, where he became a court gentleman working for the Imperial Secretariat.[1][4] He was promoted to Chief Astronomer for the Han court under Emperor An, serving his first term from 115 c. 120 and his second under the succeeding emperor from 126 - 132.[4] As Chief Astronomer, Zhang was a subordinate of the Minister of Ceremonies, ranked just below the Three Excellencies.[9] In addition to recording heavenly observations and portents, preparing the calendar, and reporting which days were auspicious or not, Zhang was also in charge of an advanced literacy test for all candidates of the Imperial Secretariat and Censorate (who were expected to know at least 9000 Chinese characters and all major writing styles).[9][10] Under Emperor An, Zhang also served as Prefect of the Majors for Official Carriages under the Ministry of Guards, in charge of the reception of memorials (containing policy and administrative suggestions) submitted to the throne as well as nominees for official appointments.[11]

A Western Han terra cotta cavalier figurine wearing robes and a hat. As Chief Astronomer, Zhang Heng earned a fixed salary and rank of 600 bushels of grain (which was mostly commuted to payments in coinage currency or bolts of silk), and so he would have worn a specified type of robe, ridden in a specified type of carriage, and held a unique emblem that marked his status in the official hierarchy.[12][13]

When the government official Dan Song proposed the Chinese calendar should be reformed in 123 to adopt certain apocryphal teachings, Zhang opposed the idea. He considered the teachings to be of questionable stature and believed they could introduce errors.[1] Others shared Zhang's opinion and the calendar was not altered, yet Zhang's proposal that apocryphal writings should be banned was rejected.[1] The officials Liu Zhen and Liu Taotu, members of a committee to compile the dynastic history Dongguan Hanji (東觀漢記), sought permission from the court to consult Zhang Heng.[1] However, Zhang was barred from assisting the committee due to his controversial views on apocrypha and his objection to the relegation of Emperor Gengshi's (r. 23–25) role in the restoration of the Han Dynasty as lesser than Emperor Guangwu's.[14][15] Liu Zhen and Liu Taotu were Zhang's only historian allies at court, and after their deaths Zhang had no further opportunities for promotion to the prestigious post of court historian.[14]

Despite this setback in his official career, Zhang was reappointed as Chief Astronomer in 126 after Emperor Shun of Han (r. 125–144) ascended to the throne.[12][16] His intensive astronomical work was rewarded only with the rank and salary of 600 bushels, or shi, of grain (mostly commuted to coin cash or bolts of silk).[12][17] To place this number in context, in a hierarchy of 20 official ranks, the lowest-paid official earned the rank and salary of 100 bushels and the highest-paid official earned 10,000 bushels during the Han.[18] The 600-bushel rank was the lowest the emperor could directly appoint to a central government position; any official of lower status was overseen by central or provincial officials of high rank.[19]

In 132, Zhang introduced an intricate seismometer to the court, which he claimed could detect the precise cardinal direction of a distant earthquake.[20] On one occasion his device indicated that an earthquake had occurred in the northwest. As there was no perceivable tremor felt in the capital his political enemies were briefly able to relish the failure of his device,[20] until a messenger arrived shortly afterwards to report that an earthquake had occurred about 400 km (248 mi) to 500 km (310 mi) northwest of Luoyang in Gansu province.[21][22][23]

A pottery miniature of a palace made during the Han Dynasty; as a palace attendant, Zhang Heng had personal access to Emperor Shun and the right to escort him

A year after Zhang presented his seismometer to the court, officials and candidates were asked to provide comments about a series of recent earthquakes which could be interpreted as signs of displeasure from Heaven.[12] The ancient Chinese viewed natural calamities as cosmological punishments for misdeeds that were perpetrated by the Chinese ruler or his subordinates on earth. In Zhang's memorial discussing the reasons behind these natural disasters, he criticized the new recruitment system of Zuo Xiong which fixed the age of eligible candidates for the title "Filial and Incorrupt" at age 40.[12] The new system also transferred the power of the candidates' assessment to the Three Excellencies rather than the Generals of the Household, who by tradition oversaw the affairs of court gentlemen.[12] Although Zhang's memorial was rejected, his status was significantly elevated soon after to Palace Attendant, a position he used to influence the decisions of Emperor Shun.[12][24] With this prestigious new position, Zhang earned a salary of 2000 bushels and had the right to escort the emperor.[25]

As Palace Attendant to Emperor Shun, Zhang Heng attempted to convince him that the court eunuchs represented a threat to the imperial court. Zhang pointed to specific examples of past court intrigues involving eunuchs, and convinced Shun that he should assume greater authority and limit their influence.[12] The eunuchs attempted to slander Zhang, who responded with a rhapsody called "Contemplating the Cosmos".[12][26] Rafe de Crespigny states that Zhang's rhapsody used imagery similar to Qu Yuan's (340–278 B.C.E.) poem "Li Sao" and focused on whether or not good men should flee the corrupted world or remain virtuous within it.[12][26]

Eastern Han tomb brick depicting the courtyard of a wealthy family's home. Zhang enjoyed a short period of retirement at his home in Xi'e, Nanyang, before being called back to the capital, where he died in 139.

Retirement and death

Zhang retired from his position under Emperor Shun in 136,[12][4] following which he was appointed Chancellor of Hejian (in modern Hebei). During his two years in office[12][4] he worked to curtail the actions of the local king, Liu Zheng, and the powerful elite families to whom the king had granted special privileges.[12][4] After arresting several lawbreakers, Zhang gained a reputation among the people of Hejian as a strict administrator.[4][27] Zhang's writing at this time reflects his bitterness at being unable to effectively serve the emperor.[12][4] Zhang retired from office in 138, and returned home to Nanyang.[4][27] There he composed a rhapsody rejoicing over the opportunity his retirement gave him to read and to play his lute.[12][27] A few months after his return home, Zhang was appointed to serve under the Imperial Secretariat and traveled back to the capital. He died there in 139, while still in office. By the time of his death, Zhang had composed thirty-two written works on literature, philosophy, science, and mysticism.[28] He was buried in his hometown Xi'e, in Nanyang Commandery; his friend Cui Yuan composed the inscription for his tomb.[28][4]

Literature and poetry

Eastern Han tomb models of watchtowers; the one on the left has crossbowmen in the top balcony. Zhang wrote that Western Han emperors were entertained by displays of archery from the balconies of towers along Chang'an's Kunming Lake.
Eastern Han tomb painting of two men engrossed in conversation; Zhang's shelun or hypothetical discourse, involved a written dialogue between imaginary or real persons to demonstrate how one could lead an exemplary life

While working for the central court, Zhang Heng had access to a variety of written materials located in the Archives of the Eastern Pavilion.[29] Zhang read many of the great works of history in his day and claimed he had found ten instances where the Records of the Grand Historian by Sima Qian (145–90 B.C.E.) and the Book of Han by Ban Gu (32 – 92 C.E.) differed from other ancient texts that were available to him.[30][1] His account was preserved and recorded in the 5th century text of the Book of Later Han by Fan Ye (398–445).[30] His rhapsodies and other literary works displayed a deep knowledge of classic texts, Chinese philosophy, and histories.[1] He also compiled a commentary on the Taixuan (太玄, "Great Mystery") by the Daoist author Yang Xiong (53 B.C.E. – 18 C.E.).[12][4][3]

Xiao Tong (501–531), a crown prince of the Liang Dynasty (502–557), immortalized several of Zhang's works in his anthology of literature, Wen xuan. Zhang's rhapsodies (fu 賦) include "Western Metropolis Rhapsody" (西京賦), "Eastern Metropolis Rhapsody" (東京賦), "Southern Capital Rhapsody" (南都賦), "Rhapsody on Contemplating the Mystery" (思玄賦), and "Rhapsody on Returning to the Fields" (歸田賦).[31] The latter fuses Daoist ideas with Confucianism and was a precursor to later Chinese metaphysical nature poetry, according to Liu Wu-chi.[32] A set of four short lyric poems (shi 詩) entitled "Lyric Poems on Four Sorrows" (四愁詩), is also included with Zhang's preface. This set constitutes some of the earliest heptasyllabic shi Chinese poetry written.[27][33] While still in Luoyang, Zhang became inspired to write his "Western Metropolis Rhapsody" and "Eastern Metropolis Rhapsody," which were based on the "Rhapsody on the Two Capitals" by the historian Ban Gu.[1]

With his Response [to Criticism] of my Idleness (Yingxian), Zhang was an early writer and proponent of the Chinese literary genre shelun, or hypothetical discourse. Authors of this genre created a written dialogue between themselves and an imaginary person (or a real person of their entourage or association); the latter poses questions to the author on how to lead a successful life.[34] He also used it as a means to criticize himself for failing to obtain high office, but coming to the conclusion that the true gentleman displays virtue instead of greed for power.[12] In this work, Dominik Declercq asserts that the person urging Zhang to advance his career in a time of government corruption most likely represented the eunuchs or Empress Liang Na's (116–150) powerful relatives in the Liang clan.[16] Declercq states that these two groups would have been "anxious to know whether this famous scholar could be lured over to their side," but Zhang flatly rejected such an alignment by declaring in this politically charged piece of literature that his gentlemanly quest for virtue trumped any desire of his for power.[35]

Achievements in Science and Technology

Astronomy and mathematics

Further information: Chinese astronomy and Chinese mathematics
Printed star map of Su Song (1020–1101) showing the south polar projection

For centuries the Chinese approximated pi as 3; Liu Xin (d. 23 C.E.) made the first known Chinese attempt at a more accurate calculation of 3.154, but there is no record detailing the method he used to obtain this figure.[36][37]In his work around 130,[38] Zhang Heng compared the celestial circle to the diameter of the earth, proportioning the former as 736 and the latter as 232, thus calculating pi as 3.1724.[39] In Zhang's day, the ratio 4:3 was given for the area of a square to the area of its inscribed circle and the volume of a cube and volume of the inscribed sphere should also be 42:32.[39] In formula, with D as diameter and V as volume, D3:V = 16:9 or V=D3; Zhang realized that the value for diameter in this formula was inaccurate, noting the discrepancy as the value taken for the ratio.[39][37] Zhang then attempted to remedy this by amending the formula with an additional D3, hence V=D3 + D3 = D3.[39] With the ratio of the volume of the cube to the inscribed sphere at 8:5, the implied ratio of the area of the square to the circle is √8:√5.[39][40] From this formula, Zhang calculated pi as the square root of 10 (or approximately 3.162).[41][12][39][24][40] In the 3rd century, Liu Hui made the calculation more accurate with his π algorithm, which allowed him to obtain the value 3.14159.[42] Later, Zu Chongzhi (429–500) approximated pi as or 3.141592, the most accurate calculation for pi the ancient Chinese would achieve.[43]

In his publication of 120 C.E.called The Spiritual Constitution of the Universe (靈憲, Ling Xian),[12] Zhang Heng theorized that the universe was like an egg "as round as a crossbow pellet" with the stars on the shell and the Earth as the central yolk.[44][45] This universe theory is congruent with the geocentric model as opposed to the heliocentric model. Although the ancient Warring States (403–221 B.C.E.) Chinese astronomers Shi Shen and Gan De had compiled the world's first star catalogue in the fourth century B.C.E., Zhang nonetheless catalogued 2500 stars which he placed in a "brightly shining" category (the Chinese estimated the total to be 14,000), and he recognized 124 constellations.[12][45] In comparison, this star catalogue featured many more stars than the 850 documented by the Greek astronomer Hipparchus (c. 190–c.120 B.C.E.) in his catalogue, and more than Ptolemy (83–161 C.E.), who catalogued over 1000.[46] Zhang supported the "radiating influence" theory to explain solar and lunar eclipses, a theory which was opposed by Wang Chong (27–97 C.E.).[47]

Extra tank for inflow clepsydra

Han Dynasty paintings on tile; being conscious of time, the Chinese believed in guardian spirits for the divisions of day and night, such as these two guardians here representing 11 P.M. to 1 A.M. (left) and 5 A.M. to 7 A.M. (right)

The outflow clepsydra was a timekeeping device used in China as long ago as the Shang Dynasty (c. 1600–c. 1050 B.C.E.), and certainly by the Zhou Dynasty (1122–256 B.C.E.).[48] The inflow clepsydra with an indicator rod on a float had been known in China since the beginning of the Han Dynasty in 202 B.C.E. and had replaced the outflow type.[48] The Han Chinese noted the problem with the falling pressure head in the reservoir, which slowed the timekeeping of the device as the inflow vessel was filled.[48] Zhang Heng was the first to address this problem, indicated in his writings from 117, by adding an extra compensating tank between the reservoir and the inflow vessel.Cite error: Closing </ref> missing for <ref> tag Joseph Needham states that this was perhaps the ancestor of all clock jacks that would later sound the hours found in mechanical clocks by the eighth century, but he notes that these figures did not actually move like clock jack figurines or sound the hours.[49] Many additional compensation tanks were added to later clepsydras in the tradition of Zhang Heng. In 610 the Sui Dynasty (581–618) engineers Geng Xun and Yuwen Kai crafted an unequal-armed steelyard balance able to make seasonal adjustments in the pressure head of the compensating tank, so that it could control the rate of water flow for different lengths of day and night during the year.[50] Zhang mentioned a "jade dragon's neck," which in later times meant a siphon.[51]

Water-powered armillary sphere

The original diagram of Su Song's (1020–1101) clock tower, featuring an armillary sphere powered by a waterwheel, escapement mechanism, and chain drive

Zhang Heng is the first person known to have applied hydraulic motive power (i.e., by employing a waterwheel and clepsydra) to rotate an armillary sphere, an astronomical instrument representing the celestial sphere.[52][53][54][55] The Greek astronomer Eratosthenes (276 - c. 194 B.C.E.) invented the first armillary sphere in 255 B.C.E. The Chinese armillary sphere was fully developed by 52 B.C.E., with the astronomer Geng Shouchang's addition of a permanently fixed equatorial ring.[56] In 84 C.E. the astronomers Fu An and Jia Kui added the ecliptic ring, and finally Zhang Heng added the horizon and meridian rings.[56][12] Zhang described this invention in his written work of 125, Apparatus for Rotating an Armillary Sphere by Clepsydra Water. The sphere itself was rotated by a turning waterwheel, which in turn was powered by the constant pressure head of water in the water clock tank.[55] His water-powered armillary influenced the design of later Chinese water clocks and led to the discovery of the escapement mechanism by the eighth century.[57]

Zhang Heng's water-powered armillary sphere had profound effects on Chinese astronomy and mechanical engineering in later generations. His model and its complex use of gears greatly influenced the water-powered instruments of later astronomers such as Yi Xing (683–727), Zhang Sixun (fl. tenth century), Su Song (1020–1101), Guo Shoujing (1231–1316), and many others. Water-powered armillary spheres in the tradition of Zhang Heng's were used in the eras of the Three Kingdoms (220–280) and Jin Dynasty (265–420), yet the design for it was temporarily out of use between 317 and 418, due to invasions of northern Xiongnu nomads.[58] Zhang Heng's old instruments were recovered in 418, when Emperor Wu of Liu Song (r. 420–422) captured the ancient capital of Chang'an. Although still intact, the graduation marks and the representations of the stars, Moon, Sun, and planets were quite worn down by time and rust.[58] In 436, the emperor ordered Qian Luozhi, the Secretary of the Bureau of Astronomy and Calendar, to recreate Zhang's device, which he managed to do successfully.[58] Qian's water-powered celestial globe was still in use at the time of the Liang Dynasty (502–557), and successive models of water-powered armillary spheres were designed in subsequent dynasties.[58]

Zhang's seismometer

A replica of Zhang Heng's seismometer, the Houfeng didong yi, featured in the Chabot Space & Science Center in Oakland, California.

In 132, Zhang Heng presented to the Han court what many historians consider to be his most impressive invention, the first seismometer. It was named Houfeng didong yi (候风地动仪, lit. instrument for measuring the seasonal winds and the movements of the Earth), and it was able to determine the exact direction (out of eight directions) of tremors and earthquakes.[53][12] According to the Book of Later Han (compiled by Fan Ye in the fifth century), his copper urn-shaped device, with a swinging pendulum inside, was able to detect the direction of an earthquake hundreds of miles/kilometers away.[59][60] This was essential for the Han government in sending quick aid and relief to regions devastated by this natural disaster.[61][62][63]The device was considered important enough to be mentioned in the "Annals" chapter of the Book of Later Han, detailing the reign of Emperor Shun.[64]

To indicate the direction of a distant earthquake, Zhang's device dropped a bronze ball from one of eight tubed projections shaped as dragon heads; the ball fell into the mouth of a corresponding metal object shaped as a toad, each representing a direction like the points on a compass rose.[65] His device had eight mobile arms (for all eight directions) connected with cranks having catch mechanisms at the periphery.[66] When tripped, a crank and right angle lever would raise a dragon head and release a ball which had been supported by the lower jaw of the dragon head.[66] His device also included a vertical pin passing through a slot in the crank, a catch device, a pivot on a projection, a sling suspending the pendulum, an attachment for the sling, and a horizontal bar supporting the pendulum.[66] Wang Zhenduo (王振铎) argued that the technology of the Eastern Han era was sophisticated enough to produce such a device, as evidenced by contemporary levers and cranks used in other devices such as crossbow triggers.[67]

Cartography

The Yu Ji Tu, or Map of the Tracks of Yu Gong, carved into stone in 1137, located in the Stele Forest of Xi'an. This 3 ft (0.91 m) squared map features a graduated scale of 100 li for each rectangular grid. Although Pei Xiu is credited with the first description of graduated scale and grid references for maps, there is evidence that Zhang Heng was the innovator.

The Wei (220–265) and Jin Dynasty (265–420) cartographer and official Pei Xiu (224–271) was the first in China to describe in full the geometric grid reference for maps that allowed for precise measurements using a graduated scale, as well as topographical elevation.[68][69] However, map-making in China had existed since at least the fourth century B.C.E. with the Qin state maps found in Gansu in 1986.[70] Pinpointed accuracy of the winding courses of rivers and familiarity with scaled distance had been known since the Qin and Han Dynasty, respectively, as evidenced by their existing maps, while the use of a rectangular grid had been known in China since the Han as well.[71][72] Historian Howard Nelson states that, although the accounts of Zhang Heng's work in cartography are somewhat vague and sketchy, there is ample written evidence that Pei Xiu derived the use of the rectangular grid reference from the maps of Zhang Heng.[73] Rafe de Crespigny asserts that it was Zhang who established the rectangular grid system in Chinese cartography.[12] Robert Temple writes that Zhang not only presented a map to the emperor in 116 C.E., but his now lost works called Discourse on New Calculations and Bird's-Eye Map "laid the groundwork for the mathematical use of the grid with maps."[74] Moreover, the Book of Later Han hints that Zhang was the first to make a mathematical grid reference, stating that he "cast a network of coordinates about heaven and earth, and reckoned on the basis of it."[74] Historian Florian C. Reiter notes that Zhang's narrative "Guitian fu" contains a phrase about applauding the maps and documents of Confucius of the Zhou Dynasty, which Reiter suggests places maps (tu) on a same level of importance with documents (shu).[75]

Odometer and South Pointing Chariot

Odometer cart from a stone rubbing of an Eastern Han Dynasty tomb, c. 125

Zhang Heng is often credited with inventing the first odometer,[45][24] an achievement also attributed to Archimedes (c. 287–212 BCE) and Heron of Alexandria (fl. CE 10–70). Similar devices were used by the Roman and Han-Chinese empires at about the same period. By the 3rd century, the Chinese had termed the device the ji li gu che, or "li-recording drum carriage" (the modern measurement of li = 500 m/1640 ft).[76]

The South Pointing Chariot was another mechanical device credited to Zhang Heng.[24] It was a non-magnetic compass vehicle in the form of a two-wheeled chariot. Differential gears driven by the chariot's wheels allowed a wooden figurine (in the shape of a Chinese state minister) to constantly point to the south, hence its name. The Song Shu (c. 500 CE) records that Zhang Heng re-invented it from a model used in the Zhou Dynasty era, but the violent collapse of the Han Dynasty unfortunately did not allow it to be preserved. Whether Zhang Heng invented it or not, Ma Jun (200–265) succeeded in creating the chariot in the following century.[77]

Legacy

Science and technology

A Florentine marble carving of Ptolemy (86–161), who created an Earth-centered universe theory that the scholars Jin Guantao, Fan Hongye, and Liu Qingfeng compare with Zhang Heng's theory published in 125[78]

Zhang Heng's mechanical inventions influenced later Chinese inventors such as Yi Xing, Zhang Sixun, Su Song, and Guo Shoujing. Su Song directly named Zhang's water-powered armillary sphere as the inspiration for his eleventh-century clock tower.[79] The cosmic model of nine points of Heaven corresponding with nine regions of earth conceived in the work of the scholar-official Chen Hongmou (1696–1771) followed in the tradition of Zhang's book Spiritual Constitution of the Universe. [80] The seismologist John Milne, who created the modern seismograph in 1876 alongside Thomas Gray and James A. Ewing at the Imperial College of Engineering in Tokyo, commented in 1886 on Zhang Heng's contributions to seismology.[81][82] The historian Joseph Needham emphasized his contributions to pre-modern Chinese technology, stating that Zhang was noted even in his day for being able to "make three wheels rotate as if they were one."[83] More than one scholar has described Zhang as a polymath.[33][3][63][23] However, some scholars also point out that Zhang's writing lacks concrete scientific theories.[78]

Poetic literature

Zhang's poetry was widely read during his life and after his death. In addition to the compilation of Xiao Tong mentioned above, the Eastern Wu official Xue Zong (d. 237) wrote commentary on Zhang's poems "Dongjing fu" and "Xijing fu".[84] The influential poet Tao Qian wrote that he admired the poetry of Zhang Heng for its "curbing extravagant diction and aiming at simplicity," in regards to perceived tranquility and rectitude correlating with the simple but effective language of the poet.[85] Tao wrote that both Zhang Heng and Cai Yong "avoided inflated language, aiming chiefly at simplicity," and adding that their "compositions begin by giving free expression to their fancies but end on a note of quiet, serving admirably to restrain undisciplined and passionate nature".[86]

Posthumous honors

Zhang was given great honors in life and in death. The philosopher and poet Fu Xuan (217–278) of the Wei and Jin dynasties once lamented in an essay over the fact that Zhang Heng was never placed in the Ministry of Works. Writing highly of Zhang and the 3rd-century mechanical engineer Ma Jun, Fu Xuan wrote, "Neither of them was ever an official of the Ministry of Works, and their ingenuity did not benefit the world. When (authorities) employ personnel with no regard to special talent, and having heard of genius neglect even to test it—is this not hateful and disastrous?"[87]

In honor of Zhang's achievements in science and technology, his friend Cui Ziyu (Cui Yuan) wrote a memorial inscription on his burial stele, which has been preserved in the Guwen yuan.[4] Cui stated, "[Zhang Heng's] mathematical computations exhausted (the riddles of) the heavens and the earth. His inventions were comparable even to those of the Author of Change. The excellence of his talent and the splendour of his art were one with those of the gods."[88] The minor official Xiahou Zhan (243–291) of the Wei Dynasty made an inscription for his own commemorative stele to be placed at Zhang Heng's tomb. It read: "Ever since gentlemen have composed literary texts, none has been as skillful as the Master [Zhang Heng] in choosing his words well ... if only the dead could rise, oh I could then turn to him for a teacher!"[89]

Several things have been named after Zhang in modern times, including the lunar crater Chang Heng,[90] the asteroid 1802 Zhang Heng,[91] and the mineral Zhanghengite.

Notes

  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 Crespigny, 1049.
  2. Tong Xiao and David Knechtges. 1996. Wen Xuan, Or, Selections of Refined Literature. (Princeton: Princeton University Press. ISBN 0691021260), 397.
  3. 3.0 3.1 3.2 3.3 3.4 Hong-sen Yan. 2007. Reconstruction Designs of Lost Ancient Chinese Machinery. (Dordrecht: Springer. ISBN 1402064594), 127.
  4. 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 4.13 4.14 4.15 4.16 Xiao & Knechtges, 398.
  5. 5.0 5.1 Asiapac Editorial, (2004). Origins of Chinese Science and Technology, Translated by Yang Liping and Y.N. Han. (Singapore: Asiapac Books Pte. Ltd. ISBN 9812293760), 120.
  6. Michael Loewe. 1968. Everyday Life in Early Imperial China during the Han Period 202 B.C.E.–CE 220. (London: B.T. Batsford Ltd.; New York: G.P. Putnam's Sons), 105.
  7. 7.0 7.1 7.2 William H. Neinhauser, Charles Hartman, Y.W. Ma, and Stephen H. West. 1986. The Indiana Companion to Traditional Chinese Literature: Volume 1. (Bloomington: Indiana University Press. ISBN 0253329833), 211.
  8. Crespigny, 1229.
  9. 9.0 9.1 Crespigny, 1222.
  10. Hans Bielenstein. 1980. The Bureaucracy of Han Times. (Cambridge: Cambridge University Press. ISBN 0521225108), 9 & 19.
  11. Crespigny, 1049 & 1223.
  12. 12.00 12.01 12.02 12.03 12.04 12.05 12.06 12.07 12.08 12.09 12.10 12.11 12.12 12.13 12.14 12.15 12.16 12.17 12.18 12.19 12.20 12.21 12.22 Crespigny, 1050.
  13. Loewe, 1968, 38–39 & 42.
  14. 14.0 14.1 Crespigny, 1049–1050.
  15. B.J. Mansvelt-Beck. 1990. The Treatises of Later Han: Their Author, Sources, Contents, and Place in Chinese Historiography. (Leiden: E.J. Brill. ISBN 9004088954), 26.
  16. 16.0 16.1 Dominik Declercq. 1998. Writings Against the State: Political Rhetorics in Third and Fourth Century China. (Leiden: Koninklijke Brill NV.), 65.
  17. Loewe, 1968, 42.
  18. Wang, 137.
  19. Yu-ch'uan Wang, "An Outline of The Central Government of The Former Han Dynasty," Harvard Journal of Asiatic Studies 12 (1/2) (June 1949): 134–187. 142 & 145.
  20. 20.0 20.1 John Minford and Joseph S.M. Lau. 2002. Classical Chinese literature: an anthology of translations. (New York: Columbia University Press. ISBN 0231096763), 307.
  21. Jon Balchin. 2003. Science: 100 Scientists Who Changed the World. (New York: Enchanted Lion Books. ISBN 1592700179), 26–27.
  22. Joseph Needham. 1986. Science and Civilization in China: Volume 3, Mathematics and the Sciences of the Heavens and the Earth. (Taipei: Caves Books, Ltd.), 627.
  23. 23.0 23.1 Krebs, 31.
  24. 24.0 24.1 24.2 24.3 Yan, 128.
  25. Crespigny, 1225.
  26. 26.0 26.1 Neinhauser et al., 211–212.
  27. 27.0 27.1 27.2 27.3 Neinhauser et al., 212.
  28. 28.0 28.1 Crespigny, 1051.
  29. Donald Harper, "Wang Yen-shou's Nightmare Poem," Harvard Journal of Asiatic Studies 47 (1) (1987): 239–283. 262.
  30. 30.0 30.1 Zongli Lu, "Problems concerning the Authenticity of Shih chi 123 Reconsidered," Chinese Literature: Essays, Articles, Reviews (CLEAR) 17 (1995): 51–68, 57.
  31. Lewis, 184.
  32. Wu-chi Liu. 1990. An Introduction to Chinese Literature. (Westport: Greenwood Press of Greenwood Publishing Group. ISBN 0313267030), 54.
  33. 33.0 33.1 Mair, 251. Cite error: Invalid <ref> tag; name "mair 251" defined multiple times with different content
  34. Declercq, 1–4.
  35. Declercq, 65–66.
  36. Needham, Volume 3, 99–100.
  37. 37.0 37.1 Jörg Arndt and Christoph Haenel. 2001. Pi Unleashed, Translated by Catriona and David Lischka. (Berlin: Springer. ISBN 3540665722), 176. Cite error: Invalid <ref> tag; name "arndt haenel lischka 176" defined multiple times with different content
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  39. 39.0 39.1 39.2 39.3 39.4 39.5 Lennart Berggren, Jonathan M. Borwein, and Peter B. Borwein. 2004. Pi: A Source Book. (New York: Springer. ISBN 0387205713), 27.
  40. 40.0 40.1 Arndt, Haenel, Lischka, 177.
  41. Wilson, 16.
  42. Needham, Volume 3, 100–101.
  43. Berggren, Borwein & Borwein, 20 & 24–26.
  44. Ray Huang. 1997. China: A Macro History. (New York: An East Gate Book, M. E. Sharpe, Inc.), 64.
  45. 45.0 45.1 45.2 Balchin, 27.
  46. Kenneth Glyn Jones. 1991. Messier's Nebulae and Star Clusters. (Cambridge: Cambridge University Press. ISBN 0521370795), 1.
  47. Needham, Volume 3, 411–413.
  48. 48.0 48.1 48.2 Joseph Needham. 1986. Science and Civilization in China: Volume 4, Physics and Physical Technology, Part 2: Mechanical Engineering. (Taipei: Caves Books, Ltd.), 479. Cite error: Invalid <ref> tag; name "needham volume 4 part 2 479" defined multiple times with different content
  49. Needham, volume 4 part 2 164.
  50. Needham, Volume 4, Part 2, 480.
  51. Needham, Volume 3, 320.
  52. Needham, Volume 4, Part 2, 30.
  53. 53.0 53.1 W. Scott Morton and Charlton M. Lewis. 2005. China: Its History and Culture. (New York: McGraw-Hill, Inc.), 70.
  54. Loewe, 1968, 107.
  55. 55.0 55.1 Temple, 37.
  56. 56.0 56.1 Needham, Volume 3, 343.
  57. Needham, volume 4 part 2 532.
  58. 58.0 58.1 58.2 58.3 Needham, Volume 4, Part 2, 483.
  59. Neehdam, Volume 4, Part 2, 484.
  60. Loewe, 1968, 106.
  61. Needham, Volume 4, Part 2, 484; Needham, Volume 3, 632.
  62. Wright, 66.
  63. 63.0 63.1 Michael Dillon. 1998. China: A Historical and Cultural Dictionary. (Surrey: Routledge Curzon Press. ISBN 0700704396), 378. Cite error: Invalid <ref> tag; name "dillon 378" defined multiple times with different content
  64. Needham, Volume 3, 632.
  65. Needham, Volume 3, 627–628.
  66. 66.0 66.1 66.2 Needham, Volume 3, 629.
  67. Needham, Volume 3, 630.
  68. Needham, Volume 3, 538–540.
  69. Mei-ling Hsu, "The Qin Maps: A Clue to Later Chinese Cartographic Development," Imago Mundi 45 (1993): 90–100, 97.
  70. Hsu, 90.
  71. Needham, Volume 3, 106–107.
  72. Hsu, 90 & 97.
  73. Nelson, 359.
  74. 74.0 74.1 Robert Temple. 1986. The Genius of China: 3,000 Years of Science, Discovery, and Invention, With a forward by Joseph Needham. (New York: Simon and Schuster, Inc. ISBN 0671620282), 30.
  75. Florian C. Reiter, "Some Remarks on the Chinese Word t'u 'Chart, Plan, Design'," Oriens 32 (1990): 308–327. 320.
  76. Needham, Volume 4, 281.
  77. Needham, Volume 4, Part 2, 40.
  78. 78.0 78.1 Guantao Jin, Fan Hongye, and Liu Qingfeng. 1996. "Historical Changes in the Structure of Science and Technology (Part Two, a Commentary)" in Chinese Studies in the History and Philosophy of Science and Technology, 165–184, edited by Fan Dainian and Robert S. Cohen, translated by Kathleen Dugan and Jiang Mingshan. (Dordrecht: Kluwer Academic Publishers. ISBN 0792334639). Cite error: Invalid <ref> tag; name "jin fan liu 170" defined multiple times with different content
  79. Needham, Volume 4, Part 2, 466.
  80. William T. Rowe. 2001. Saving the World: Chen Hongmou and Elite Consciousness in Eighteenth-Century China. (Stanford: Stanford University Press. ISBN 0804748187), 88.
  81. Yan, 124.
  82. Needham, Volume 3, 626.
  83. Needham, Volume 4, 85–86.
  84. Robert Joe Cutter, "Cao Zhi's (192-232) Symposium Poems," Chinese Literature: Essays, Articles, Reviews (CLEAR) 6 (1/2) (1984): 1–32, 11 (footnote 61), 15, (footnote 80), 26 (footnote 141).
  85. Kwong Yim-tze, "Naturalness and Authenticity: The Poetry of Tao Qian," Chinese Literature: Essays, Articles, Reviews (CLEAR) 11 (1989): 35–77, 63.
  86. James Robert Hightower, "The Fu of T'ao Ch'ien," Harvard Journal of Asiatic Studies 17 (1/2) (1954): 169–230, 169–170.
  87. Needham, Volume 4, 42.
  88. Needham, Volume 3, 359.
  89. Dominik Declercq. 1998. Writings Against the State: Political Rhetorics in Third and Fourth Century China. (Leiden: Koninklijke Brill NV.), 247.
  90. "Lunar Names Proposed," Science News 90 (16) (1966): 290.
  91. Lutz D. Schmadel. 2003. Dictionary of Minor Planet Names: Fifth Revised and Enlarged Edition. (New York: Springer. ISBN 3540002383), 144.

References
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External links

All links retrieved October 16, 2020.

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