Lexicography was perhaps the department of pure scholarship in which the greatest advances were made. Dictionaries on the phonetic system, based upon the work of Lu Fa-yen of the sixth century, came very much into vogue, as opposed to those on the radical system initiated by Hsü Shên. Not that the splendid work of the latter was allowed to suffer from neglect. LI YANG-PING, of the eighth century, devoted much time and labour to improving and adding to its pages. The latter was a Government official, and when filling a post as magistrate in 763, he is said to have obtained rain during a drought by threatening the City God with the destruction of his temple unless his prayers were answered within three days. [Sidenote: CHANG CHIH-HO] CHANG CHIH-HO (eighth century), author of a work on the conservation of vitality, was of a romantic turn of mind and especially fond of Taoist speculations. He took office under the Emperor Su Tsung of the T‘ang dynasty, but got into some trouble and was banished. Soon after this he shared in a general pardon; whereupon he fled to the woods and mountains and became a wandering recluse, calling himself the Old Fisherman of the Mists and Waters. He spent his time in angling, but used no bait, his object not being to catch fish. When asked why he roamed about, Chang answered and said, “With the empyrean as my home, the bright moon my constant companion, and the four seas my inseparable friends,--what mean you by _roaming_?” And when a friend offered him a comfortable home instead of his poor boat, he replied, “I prefer to follow the gulls into cloudland, rather than to bury my eternal self beneath the dust of the world.” The author of the _T‘ung Tien_, an elaborate treatise on the constitution, still extant, was TU YU (_d._ 812). It is divided into eight sections under Political Economy, Examinations and Degrees, Government Offices, Rites, Music, Military Discipline, Geography, and National Defences. [Sidenote: LIU TSUNG-YÜAN] Among writers of general prose literature, LIU TSUNG-YÜAN (773-819) has left behind him much that for purity of style and felicity of expression has rarely been surpassed. Besides being poet, essayist, and calligraphist, he was a Secretary in the Board of Rites. There he became involved in a conspiracy, and was banished to a distant spot, where he died. His views were deeply tinged with Buddhist thought, for which he was often severely censured, once in a letter by his friend and master, Han Yü. These few lines are part of his reply on the latter occasion:--