Yüan [q. v.]; Mêng Sên, Ch'ing-ch'u san ta i-an k'ao-shih II, 4b (char. in bibl. of Fu-lin).]
MEI Ku-ch'êng 梅瑴成 (T. 玉汝, H. 循齋, 柳下居士), d. Nov. 20, 1763, age 83 (sui), official and mathematician, grandson of Mei Wên-ting [q. v.], was a native of Hsuan-ch'êng, Anhwei. In 1712 he was recommended to serve the emperor as a mathematician, and was given the rank of a student of the Imperial Academy. Thereafter, until the end of the K'ang-hsi period (1722), he served in the studio, Mêng-yang chai (see under Fang Pao), and as one of the editors of the compendium on music, mathematics, and the calendar, known as the Lü-li yüan-yüan (see under Ho Kuo-tsung). In 1714 he was given the degree of chü-jên and in the following year, the privilege of taking the Palace examination for his chin-shih degree without first passing the metropolitan examination. After becoming a chin-shih (1715) he was selected a bachelor of the Hanlin Academy, and later was made a Hanlin compiler—a post he held until 1729 when he was appointed censor and sent to supervise the transportation of tribute grain at Tungchow. After being several times promoted, and once degraded, he was in 1747 made a vice-president of the Censorate and thereafter held the posts of junior vice-president of the Board of Punishments (1748–50) and president of the Censorate (1750–53). He retired in 1753, but four years later, in deference to his age, was granted by Emperor Kao-tsung the privilege of retaining for the remainder of his life the stipend of his rank (president of the Censorate). In 1762, when the Emperor made his third tour of South China, he greeted Mei who was then eighty-two sui, at Ch'ing-chiang p'u, on the Grand Canal, presented him a poem and conferred on one of his sons the degree of chü-jên. Mei died the following year and was canonized as Wên-mu 文穆.
Mei Ku-ch'êng did not write as extensively as his grandfather. He collaborated in the compilation of the afore-mentioned Lü-li yüan-yüan and later (1737–46) worked on its supplements, entitled Li-hsiang k'ao-ch'êng hou-pien and Lü-lü chêng-i hou-pien (see under Ho Kuo-tsung). He also served on the commission which finally edited the Ming Dynastic History (Ming-shih), checking especially the section on astronomy and the calendar which, he asserted, was originally the work of his grandfather, but owing to frequent editing and recopying, contained many errors which he had to correct. During his retirement he reedited (1760) the Suan-fa t'ung-tsung of Ch'êng Ta-wei [q. v.] and reprinted (1771) the collected works of his grandfather (see under Mei Wên-ting). To these works he added two of his own on mathematics and the calendar, entitled 赤水遺珍 Ch'ih-shui i-chên and 操縵巵言 Ts'ao-man chih-yen, each in 1 chüan. In the former he reproduced three of the nine mathematical formulae, dealing with the circle expressed in series, which had been introduced by the French Jesuit, Pierre Jartoux 杜德美 (1669–1720). It is said that Mei also left a work of miscellaneous notes, entitled 柳下舊聞 Liu-hsia chiu-wên, in 16 chüan, and a work on spherical trigonometry.
Mei Ku-ch'êng was interested in the history and the preservation of the old astronomical instruments of the Yüan and Ming dynasties and deplored their partial destruction in his day. Some of these instruments were in use until 1672 when new ones were constructed under the supervision of Ferdinand Verbiest (see under Lu Lung-chi). Mei reports that in the years 1713–14 he often saw them in storage, but that in 1715 Bernard-Kilian Stumpf 紀理安 (1655–1720), who was then in charge of the Board of Astronomy, had several valuable ones melted and the bronze used to make a quadrant (象限儀). By 1744 the armillary sphere (渾天儀), the compendium instrument (簡儀), and the celestial globe (天體儀) were, according to Mei, the only older instruments left.
Mei Ku-ch'êng is important in the history of Chinese mathematics, not so much for his writings, as for the encouragement he gave to the study of older Chinese works on mathematics and to the recovery of works believed to have been lost. He pointed out that the algebra introduced from the West was the same in principle as the Chinese method of manipulating unknowns, called li t'ien-yüan i 立天元一, employed in the work 測圓海經 Ts'ê-yüan hai-ching, 20 chüan, written in 1248 by an official of the Yüan dynasty named Li Chih 李治 or Li Yeh 冶 (仁卿, 敬齋, 1192–1279). Mei attributed the loss of these methods to the ignorance of Ming scholars.
[1/511/14a; 3/73/1a; 17/3/62b; Hsüan-ch'êng hsien-chih (1888) 15/18b; Juan Yüan [q. v.], Ch'ou-jên chuan (1799) 39/1a; Ssŭ-k'u 107/11b; Chung-kuo suan-hsüeh shih and Chung-suan shih lun-ts'ung (for both see under Lo Shih-lin); Mikami Yoshio, The Development of Mathematics in China and Japan (1913), pp. 120–22, 142–43.]
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