What is zhang heng famous for

His invention is known as the water-powered celestial sphere. By adding a few additional gears, Zhang Heng was able to drive a pillar that demonstrated the waxing and waning of the moon.

Zhang Heng was the first person in China to construct a rotating celestial globe and also the inventor of a primitive seismograph for measuring earthquakes and the inventor of the odometer, or "mileage cart". His use of the square root of 10 in the searching for pi is one of the earliest approximations known. Beyond that, he excelled in writing and visual arts.

In fact, he was also considered one of the four great painters of his era. Collection Landsberger collection. Theme Socialist Spiritual Civilization Visualizing the Future.

Tags China. Search this site Search. Born in a town north of modern Nanyang City, Henan Province, Zhang Heng came from a distinguished, but not very affluent family. His grandfather, who served as governor of a commandery, died when Zhang was 10 years old, leaving him in the care of his mother and grandmother. He was charged with recording heavenly observations and portents, preparing the calendar, and reporting which days were auspicious.

With his Response [ to Criticism ] of My Idleness , Zhang was an early writer and proponent of the Chinese literary genre shelun , or hypothetical discourse. Authors of this genre create a written dialogue between themselves and an imaginary person or a real person of their entourage or association.

For centuries, the Chinese approximated pi as 3; Liu Xin 23 AD made the first known Chinese attempt at a more accurate calculation of 3. Around AD , Zhang Heng compared the celestial circle to the diameter of the Earth, proportioning the former as and the latter as , thus calculating pi as 3. Zhang Heng began his studies in astronomy at the age of 30, and began publishing his works in astronomy and mathematics. In comparison, this star catalog featured many more stars than the documented by the Greek astronomer Hipparchus c BC in his catalog, and more than Ptolemy AD , who cataloged over 1, Zhang Heng is the first person known to have applied hydraulic motive power i.

The sphere itself was rotated by a turning waterwheel, which in turn was powered by the constant pressure from the head of water in the water clock tank. His water-powered armillary influenced the design of later Chinese water clocks and led to the discovery of the escapement mechanism by the 8th century. His bronze, urn-shaped device was called h oufeng didong yi instrument for measuring the seasonal winds and the movements of the Earth , and had a swinging pendulum inside.

As such, he was thus able to detect the direction of an earthquake hundreds of miles away. This was essential for the Han authorities in sending quick aid and relief to regions devastated by this natural disaster.

Map-making in China had existed since at least the 4th century BC, with the Qin State maps found in Gansu in that accurately pinpointed the winding courses of rivers and streams. After 1 li 1, feet was traversed, a mechanically driven wooden figure struck a drum, and after 10 li had been covered, another wooden figure struck a gong or a bell with its mechanically operated arm.

The south-pointing chariot, an ancient Chinese 2-wheeled vehicle with a figure that always pointed south and acted as a compass, was another mechanical device credited to Zhang Heng. Odometer cart from a stone rubbing of an Eastern Han Dynasty tomb, c.

Public Domain. Top image: Zhang Heng's odometer, a mechanical carriage. Asiapac Editorial. Origins of Chinese Science and Technology. Translated by Yang Liping and Y. To place this number in context, in a hierarchy of twenty official ranks, the lowest-paid official earned the rank and salary of bushels and the highest-paid official earned 10, bushels during the Han. The 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.

In , Zhang introduced an intricate seismoscope to the court, which he claimed could detect the precise cardinal direction of a distant earthquake. 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, until a messenger arrived shortly afterwards to report that an earthquake had occurred about km mi to km mi northwest of Luoyang in Gansu province.

A year after Zhang presented his seismoscope 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. 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 forty.

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. 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.

With this prestigious new position, Zhang earned a salary of 2, bushels and had the right to escort the emperor. 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.

The eunuchs attempted to slander Zhang, who responded with a fu rhapsody called " Fu on Pondering the Mystery", which vents his frustration. Rafe de Crespigny states that Zhang's rhapsody used imagery similar to Qu Yuan's — BC poem "Li Sao" and focused on whether or not good men should flee the corrupted world or remain virtuous within it.

While working for the central court, Zhang Heng had access to a variety of written materials located in the Archives of the Eastern Pavilion. 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 —90 BC and the Book of Han by Ban Gu AD 32—92 differed from other ancient texts that were available to him.

His account was preserved and recorded in the 5th century text of the Book of Later Han by Fan Ye — His rhapsodies and other literary works displayed a deep knowledge of classic texts, Chinese philosophy, and histories. The latter fuses Daoist ideas with Confucianism and was a precursor to later Chinese metaphysical nature poetry, according to Liu Wu-chi. This set constitutes some of the earliest heptasyllabic shi Chinese poetry written.

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. These two works satirized and criticized what he saw as the excessive luxury of the upper classes.

In Zhang Heng's poem "Four Sorrows", he laments that he is unable to woo a beautiful woman due to the impediment of mountains, snows and rivers. Knechtges claim that Zhang wrote this as an innuendo hinting at his inability to keep in contact with the emperor, hindered by unworthy rivals and petty men. This poem is one of the first in China to have seven words per line. His "Four Sorrows" reads:. In Taishan stays my dear sweetheart, But Liangfu keeps us long apart; Looking east, I find tears start.

She gives me a sword to my delight; A jade I give her as requite. I'm at a loss as she is out of sight; Why should I trouble myself all night? This simpler type of fu poem influenced later works by the prominent official and scholar Cai Yong — Zhang wrote:. Ah, the chaste beauty of this alluring woman! She shines with flowery charms and blooming face. She is unique among all her contemporaries. She is without a peer among her comrades.

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. Exemplifying his attention to detail, his rhapsody on Nanyang described gardens filled with spring garlic, summer bamboo shoots, autumn leeks, winter rape-turnips, perilla, evodia, and purple ginger.

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 li one li in Han times was equal to Along with Sima Xiangru — BC , 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 or southern China.

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 tall towers along Chang'an's Kunming Lake. 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.

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 Buddha with the vision of the white elephant bringing about conception.

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. 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.

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's — powerful relatives in the Liang clan.

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.

Zhang wrote about the various love affairs of emperors dissatisfied with the imperial harem, going out into the city incognito to seek out prostitutes and sing-song girls. This was seen as a general criticism of the Eastern Han emperors and their imperial favorites, guised in the criticism of earlier Western Han emperors. Besides criticizing the Western Han emperors for lavish decadence, Zhang also pointed out that their behavior and ceremonies did not properly conform with the Chinese cyclical beliefs in yin and yang.

In a poem criticizing the previous Western Han Dynasty, Zhang wrote:. Those who won this territory were strong; Those who depended on it endured. When a stream is long, its water is not easily exhausted. When roots are deep, they do not rot easily.

Therefore, as extravagance and ostentation were given free rein, The odour became pungent and increasingly fulsome. For centuries the Chinese approximated pi as 3; Liu Xin d.

AD 23 made the first known Chinese attempt at a more accurate calculation of 3. In his work around , Zhang Heng compared the celestial circle to the diameter of the earth, proportioning the former as and the latter as , thus calculating pi as 3. In Zhang's day, the ratio 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 2 :3 2.

From this formula, Zhang calculated pi as the square root of 10 or approximately 3. This universe theory is congruent with the geocentric model as opposed to the heliocentric model.

Although the ancient Warring States — BC Chinese astronomers Shi Shen and Gan De had compiled China's first star catalogue in the 4th century BC, Zhang nonetheless catalogued 2, stars which he placed in a "brightly shining" category the Chinese estimated the total to be 14, , and he recognized constellations.