Qin Jiushao

Background

Jiushao was born c. 1202, in Ziyang, Sichuan, China. His family came from Shandong province. His father, Qin Chi-yu, was a civil servant.

Education

In 1219 Qin joined the army as the head of a unit of territorial volunteers and participated in curbing a rebellion staged by Chang Fu and Mo Chin. In 1224-1225 he followed his father when the latter was transferred to the Sung capital, Chung-tu (now Hangzhou). There he had the opportunity to study astronomy at the astronomical bureau under the guidance of the official astronomers.

Career

Qin's father was sent to the prefecture of Santai, and Qin had to leave the capital. About 1233 he served as a sheriff in one of the sub-prefectures in Szechuan. The Mongols invaded Szechuan in 1236, and Qin fled to the east, where he first became a vice administrator in Chizhou prefecture and the governor of Ho-chou (now Ho-hsien in Anhwei province). In the latter part of 1244 Qin was appointed one of the vice-administrators of the superior prefecture of Nanking, but some three months later he relinquished this post because of his mother’s death. He returned to Hu’chou (now Wuhsing in Chekiang province), and it was probably there that he wrote his celebrated mathematical treatise Shu-shu chiu-chang (“Mathematical Treatise in Nine section”), which appeared in 1247. In the preface of this book Qin mentions that he learned mathematics from a certain recluse scholar, but he does not give his identity.

As precipitation was important agriculture and food production, Qin developed precipitation gauges that was widely used in 1247 during the Southern Song dynasty to gather meteorological data. Qin later records the application of rainfall measurements in the mathematical treatise. The book also discusses the use of large snow gauges made from bamboo situated in mountain passes and uplands which are speculated to be first referenced to snow measurement.

Qin recorded the earliest explanation of how Chinese calendar experts calculated astronomical data according to the timing of the winter solstice. Among his accomplishments are the introduction techniques for solving certain types of algebraic equations using a numerical algorithm (equivalent to the 19th century Horner's method) and for finding sums of arithmetic series. He also introduced the use of the zero symbol into written Chinese mathematics.

In 1254 Qin returned to Chung-tu to re-enter civil service, but for some unknown reason he soon resigned and went back to his native home. He paid a visit to Chia Shih-tao, an influential minister at that time, and was appointed governor of Ch’iung-chou (in modern Hainan) in 1258. A few months later, however, Qin was dismissed because of charges of bribery and corruption. Nevertheless, he managed to find another job as a civil aide to an intimate friend of his, Wu Ch’ien, who was then in charge of marine affairs in the district of Yin (near modern Ningpo in Chekiang province). Wu Ch’ien eventually became a minister, but in 1260 he lost favor and was given a lesser assignment in south China. Qin followed his friend to Kwangtung province and received an appointment in Mei-chou (now Mei-hsien), where he died shortly afterward. The year of Qin's death has been estimated as 1261, for there was an edict in the following year banning Wu Qin and his associates from the civil service.

Achievements

• Qin was accomplished in many other fields and held a series of bureaucratic positions in several Chinese provinces. Among his accomplishments are the introduction techniques for solving certain types of algebraic equations using a numerical algorithm (equivalent to the 19th century Horner's method) and for finding sums of arithmetic series.

Works

More photos

• book

  • Shu shu jiu zhang

    ((Chinese Edition))

    1247

Connections

Father:

Qin Chi-yu

References

• Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures 2 Volume Set
  2008
• Precipitation: Theory, Measurement and Distribution Precipitation plays a significant role in the climate system, and this book, originally published in 2006, was the first to provide a comprehensive examination of the processes involved in the generation of clouds, rain, snow and hail; how precipitation is measured; how its distribution has changed over time; and how we still need to make improvements to the way precipitation is measured.
  2006
• Chinese Mathematics in the Thirteenth Century An exploration of the life and work of the thirteenth-century mathematician Qin, this fascinating book examines a range of mathematical issues that reflect Chinese life of a millennium ago.