中英雙語話中國歷史名人 第86期:祖沖之

Zu Chongzhi(429~500), whose courtesy name was Wenyuan, was a famous mathematician and astronomer living in the Song and Qi of the Southern Dynasty. He was a native of Fanyang (now Laiyuan, Hebei Province).

祖沖之(429 ~500 ) , 字文遠，南朝宋齊范陽(今河北淶源)人。

He did not take for granted the established theories of previous scholars and was skeptical to their specious academic conclusions.

他主張決不“虛推古人”，批判地接受前代的學術遺產，敢於懷疑古人錯誤陳舊的結論。

Audaciously, he insisted to put forward new theories by precise measurements and prudent calculations.

親自進行精密測量和仔細推算，勇於提出自己的新見解。

After careful observations, he identified the mistakes of the calendar used then and compiled an updated one called the "Daming Calendar" (or Calendar of Great Brightness), the best at his time. In the entire history of China, Zu Chongzhi became the first to take into consideration in calendar calculations the differences between the tropical and siderreal years.

經過實際觀測，祖沖之指出何承天編制、爲當時劉宋王朝奉行的元嘉歷有不少錯誤。於是編制了新曆法《大明曆》，在中國曆法史上第一次考慮了歲差影響，是當時最好的歷法。

As a mathematician, Zu Chongzi's most remarkable achievement was the calculation of pi. The "precise value" he worked out as the ratio of the circumference of a circle to its diameter is as 355/113, that is, a number between 3.1415926 and 3. 1415927.

祖沖之在數學領域的卓越貢獻就是對圓周率的推算，使其精確到小數點後的7位數，介於3.1415926和3.1415927之間。

In the Tang Dynasty, the mathematical work Zhui Shu (or Method of Interpolation) compiled by Zu (now lost) was a required textbook at the Academy of Mathematics, in which students were obliged to read it for four years, the longest time any textbook was required to work on. This book was later circulated to Japan and Korea.

祖沖之的數學專著《綴術》現已失傳，在唐代曾作爲國子監算學館的必讀書，學習期限4年，是時限最長的一種，後來還流傳至日本和朝鮮。

It was said that Zu Chongzhi was also an inventor. He successfully replicated the legendary compass wagon and wooden oxen and horses, mechanical vehicles said to have been invented by Zhuge Liang and used to facilitate transportation.

祖沖之成功地復原過指南車與諸葛亮的木牛流馬，他製造的“欹器”用來盛水，“中則正,滿則覆”。

He was also the inventor of a "tilted container" used to bail water and a long-distance boat believed to have the capacity of traveling over 50 kilometers a day.

祖沖之還製造過一種千里船，並在江上試航，日行百餘里。