The Research Of Metrology In Tang Dynasty

Metrology is the knowledge and technical instrument about the national economy and the people's livelihood, and the foundation that keeps the national instrument on working normally and the science and technology developing persistently and steadily. In ancient China, abundant practices of metrology were accumulated. They were organic components of excellent Chinese traditional culture. In current years, the research of metrology has been attached more and more importance in academic circle. This dissertation just conforms to this academic tendency. The Tang Dynasty (A.D.618~907) is selected as an analysis case. Through the research of weights and measures, wind metrology, time metrology, astronomical metrology and angle metrology during Tang Dynasty, the theories, methods, instruments and management of metrology as well as metrological characteristic in Tang Dynasty are investigated in this dissertation, which fills in the gap in this field to a certain extent.In Chapter One the management of weights and measures is discussed. In Tang Dynasty, the systems of weights and measures carried on practising the same systems that were divided into one big system and one small system in the Sui Dynasty. The possible manufacture departments of weights and measures were the Tai Fu Temple (太府寺), the Tai Chang Temple (太常寺) and the Zhong Shang Bureau (中尚署). Among three departments, the Tai Fu Temple probably manufactured the stardard apparatus of the big system of weights and measures, the Tai Chang Temple possibly made the stardard apparatus of the small system and the Zhong Shang Bureau only produced the beautiful rulers as the national presents. The administrative organs of the management of weights and measures were the Tai Fu Temple, the Ministry of Finance (金部) and local officials in every states and counties. Special emphasis is laid on the enacting and executing of administerial system and technical management measures. In addition, many decrees relating to the management of weights and measures were worked out and issued by the central government. This dissertation defines the respective duty of different administrant officials in the Tai Fu Temple and every states and counties. It also studies the keeping and circulation of weights and measures that is lack of adequate research in the past years. Some ill-considered opinions are corrected and the meaning of various penalties in some pieces of laws and decrees relating to weights and measures is distinguished.In Chapter Two Li Chunfeng's studies to weights and measures are analyzed. Li Chunfeng, a famous scholar in the Tang Dynasty, had made great efforts to study the weights and measures of previous dynasties and record the development and difference of weights and measures in the temperament and calendrical chapter of Sui Shu《(隋书》) and Jin Shu (《晋书》). His explorations involved many scholars who gained achievements and preserved some contents in ancient books and records which have been lost at present relating to weights and measures. In addition, almost complete apparatus of weights and measures of previous dynasties and valuable historical events were also described in his explorations. Compared with other scholars of the Tang Dynasty, he collected quite a number of historical materials as well as adopted appropriate methods. Therefore, his researches affected subsequent studies to a certain extent. There were also some woeful parts in his studies of weights and measures. By the study of Li Chunfeng's work, the significance in his work and some ill-considered content are discussed. For example, in Shen Du (审度) chapter of the temperament and calendrical chapter of Sui Shu, Yuan Kuang (元匡) who hold the post of Zhong Wei (中尉) and took part in the discussion about the long measure then was mistaken for Yuan Yanming (元延明) in Northern Wei Dynasty (北魏). In addition, the circumstance of the preservation or loss about the historical materials that Li Chunfeng quoted in the temperament and calendrical chapter of Sui Shu and Jin Shu are investigated. The method by which he researched weights and measures is also analyzed.In Chapter Three square standard measure (方形嘉量) Zhang Wenshou made is discussed. Zhang Wenshou was a famous scholar then, too. He ever contrived a new kind of square standard measure. His work was formerly introduced curtly and not studied seriously. In fact, on the one hand, his quadrate measure carried forward the characteristic of bronze square sheng of Shang Yang (商鞅铜方升) during Qin (秦) of the Warring States. System error caused by pi during the manufacture of circular measure was whole averted on his quadrate measure. On the other hand, Zhang Wenshou absorbed the advantages of bronze standard measure of Wang Mang during Xin (新莽嘉量) and complicated the structure of the square measure. His quadrate measure included the five sub-measures, namely yue (龠), ge (合), sheng (升), dou (斗), hu (斛). This kind of design was really advanced comparatively then. For a great variety of reasons, his square standard measure did not gain more attention in Tang Dynasty. However, Zhang Wenshou's square standard measure affected the manufacture of the square measure to a certain extent in later ages. In Qing Dynasty, square standard measure at the time of the reign of Qian Long Emperor imitated the shape of Zhang Wenshou's square standard measure. Therefore, this piece of square standard measure that Zhang Wenshou contrived is an innovation in the history of weights and measures for a certainty.In Chapter Four the wind metrology is investigated. This chapter mainly includes Li Chunfeng's contribution to wind-force and weather vane. In Yi Si Zhan (《乙巳占》), he firstly elaborated the different classes of the wind-force in Chinese history. In order to compare the wind-force, Li Chunfeng classified the wind-force into eight different classes according to the effect of the wind. Thence the different classes of wind-force embodied the independent concepts and the respective intensities. In a sense, he not only classified the wind-force consciously, but also quantified the wind primarily. Although Li Chunfeng's classification and quantification for wind-force were relatively sketchy, it indicated that ancient simple qualitative classification for wind-force was running to the combination of qualitative classification and quantification then. Moreover, Li Chunfeng benefited from ancient knowledge of weather vane. He recorded and narrated the manufacturing methods of two weather vanes in Yi Si Zhan, namely Hou Feng Yu Bao (候风羽葆) and Xiang Feng Wu (相风乌). The applied occasion of two weather vanes and the condition of measuring wind that had not been attached importance were also discussed by Li Chunfeng. His elaboration was profound and had become the standard of imitating for later ages after Tang Dynasty. In this chapter the former ill-considered studies are analyzed, too.In Chapter Five the time metrology is studied. The manufacture and management of clepsydra was discussed in this chapter. Through the research of many historical materials concerning the clepsydra, the different characteristics in organizational system and managing duty are compared among three organs of the management of clepsydra, administerial system and technical management measure as well as legal system relating to the clepsydra timing are elaborated, and three pieces of legal precedents relating to the clepsydra in Tang Dynasty are analyzed. The probable manufacture departments of clepsydra was the Crown Prince Shuai Geng Temple (太子率更寺). That is to say, according to the structure of floating arrow clepsydra (浮箭漏) that Lv Cai (吕才) made and the steelyard clepsydra (秤漏) prevailing in Tang Dynasty, the Zuo Jiao Bureau (左校署)under the command of the Jiang Zuo Jian (将作监) possibly sent for providing help to manufacture the four cabinets filling water of floating arrow clepsydra, and that the Tai Fu Temple being responsible for making the weights and measures was perhaps in charge of supplying the manufacturing technique of arrow for floating arrow clepsydra and steelyard for steelyard clepsydra. The reason for this is that the precision of arrow and steelyard was highly required relatively. Besides the above-mentioned central departments, some local officials also occasionally made clepsydras that were applied locally. In addition, common people made the clepsydras having different structures, too. For example, the famous clepsydra using a rolling ball (辊弹漏刻) was made by a monk in Tang Dynasty. The administrative organs of the management of clepsydra were the Ministry of Sacrifice (祠部), the Astronomical Bureau (太史局) and the Crown Prince Shuai Geng Temple. The Ministry of Sacrifice was in charge of the affairs of clepsydra in all sorts of sacrificial ceremonies and the number of officials relating to clepsydra was the least among three above-mentioned administrative organs. The Qie Hu Zheng (挈壶正) being under the command of the Astronomical Bureau managed the comprehensive affairs concerning clepsydra. There were the maximum departments and officials of managing clepsydra in the Qie Hu Zheng. And the Crown Prince Shuai Geng Temple supervised the administration of clepsydra relating to the activities of imperial kinsmen and crown prince. Generally, the Astronomical Bureau managed the technical direction about clepsydra. The Ministry of Sacrifice and the Crown Prince Shuai Geng Temple took on the concrete management of clepsydra being aimed at specific demand. In addition to the timing system of Hundred Mark Chronometry, the administerial systems of clepsydra including the ordinary timing system and formal timing system as well as military timing system are described. The technical management of clepsydra was administrated by the Astronomical Bureau. Moreover many decrees on the basis of clepsydra as a technical instrument of timing were also worked out and issued as well as enforced strictly in Tang Dynasty.In Chapter Six the astronomical metrology is introduced. The main content in this chapter is the respective contributions of Li Chunfeng and Monk Yi Xing to astronomical instruments. On a basis of analyzing the historical materials, the armillary spheres and celestial globe in Tang Dynasty are compared with the former instruments in respect of structure and function. Innovation and improvement that Li Chunfeng and Monk Yi Xing made during the manufacture of astronomical instruments are investigated.Special emphasis is laid on the functions relating to time counting and time service with astronomical instruments in Tang Dynasty. Besides, the precision of time measurement with astronomical instruments and the certain design that caused the system error in respect of time counting for astronomical instruments are explored. Among all sorts of armillary spheres in ancient China, the armillary sphere with ecliptic ring (浑天黄道仪) made by Li Chunfeng bear a transitional significance in the development of armillary sphere. It made up the lack of ecliptic ring with the iron armillary sphere applied in astronomical bureau in Northern Wei Dynasty (北魏太史候部铁仪) and improved the structure of the bronze armillary sphere with ecliptic ring in Eastern Han Dynasty (东汉太史黄道铜仪). And it set an example for subsequent manufacture of armillary sphere in Tang Dynasty. Compared with former scholars who made armillary spheres, Li Chunfeng increased the number of rings and the type of graduations in armillary sphere and installed the lunar orbit ring (白道环) for the first time in the San Chen Yi (三辰仪) that was the one of constituent parts of the armillary sphere with ecliptic ring. Furthermore, he banded the ecliptic ring and equator ring together in the San Chen Yi and graduated the 12-Earth-Branch Chronometry for measuring time sketchily in horizon ring. By utilizing the San Chen Yi, the coordinates of the ecliptic, lunar orbit and celestial equator for one celestial body were capable of being conveniently measured comparatively. The relation among the three kinds of coordinates was also able to be made certain. Subsequently Monk Yi Xing manufactured the armillary sphere with a movable ecliptic ring (黄道游仪). In the structure of this instrument, he added Tian Ding Dan Huan (天顶单环) that former armillary sphere never had, and connected the ecliptic ring and equator ring as well as the ecliptic ring and lunar orbit ring each other respectively by holes drilled on the surface of rings in the San Chen Yi. Moreover, he inlayed the silver nails on the surface of Xuan Shu Shuang Huan (旋枢双环) and Yang Jing Shuang Huan (阳经双环), and graduated the Hundred Mark Chronometry on the surface of both horizon ring and ecliptic ring. In addition, Monk Yi Xing and Liang Lingzan manufactured a new-style water-rotating celestial globe named Shui Yun Hun Tian Fu Shi Tu (水运浑天俯视图). This water-rotating celestial globe not only demonstrated multifarious astronomical phenomena and measured time, but also announced the Shi (the 12 divisions of a day) and Ke (the 100 divisions of a day) by certain automatic time service system. Monk Yi Xing increased a wooden cabinet on the water-rotating celestial globe. The wooden cabinet was capable of realizing the function of time service as the platform for time service of two wooden men and ensuring that the mechanism of celestial globe could run correctly and the measurement had definite veracity. The Shui Yun Hun Tian Fu Shi Tu actually was a complex astronomical instrument that also added the time service system on a basis of the traditional water-rotating celestial globe. In a sense, such an astronomical instrument appeared for the first time in the history of Chinese armillary sphere and celestial globe.In Chapter Seven the angle metrology is discussed. Gautama Siddhartha (瞿昙悉达), who was an astronomer in Tang Dynasty, translated and compiled the Jiuzhi Calendar (《九执历》) on ancient India astronomy, in which the 360°circumference division system was introduced into China for the first time. Since it was different from the Chinese traditional 3651/4 circumference division system, Gautama Siddhartha had three conditions before introducing it. By reviewing Gautama Siddhartha's work, the reasons why the 360°division system were not accepted in Tang Dynasty are analyzed, special emphasis is laid on the research of its effects on astronomy and mathematics as well as its innovative significance for the study of metrology history. Despite the 360°division system in the Jiuzhi Calendar was not accepted in Tang Dynasty and this did not turn the Chinese angle measurement into the angle metrology, the introduction of 360°division system affected the improvement of the calculation in contemporaneous Chinese calendrical astronomy. When Monk Yi Xing (僧一行) compiled the Dayan Calendar (《大衍历》), he assimilated rational components in the 360°circumference division system.To sum up, a notable characteristic about different metrologies in Tang Dynasty is that the inheritance and innovation of metrology are paid equal attention. On the basis of carrying on the metrologies in previous dynasties, different metrologies in Tang Dynasty were carried forward to more extent and many remarkable achievements were gained generally. The effect of the metrologies in Tang Dynasty to later ages was profound and lasting.