The value of pottery for architectural purposes was recognised in China from the earliest times. Unglazed bricks and tiles of Han and pre-Han periods are preserved by Chinese collectors, particularly when they happen, as is often the case, to have inscriptions in old seal characters, or other ornament. The familiar Chinese roof tile is a long convex object like a horizontal section of a tube, and those intended for the border are ornamented at one end with a disc, usually stamped with a dragon or other design in sunk relief. Here and there, on the apex of the roof or at the corners, are ornamental tiles carrying figures of deities, heroes, mythical creatures or birds, modelled in the round and usually with great force and skill. Besides these, architectural mouldings and antefixal ornaments in pottery are commonly used on temples and pavilions of an ornamental kind. The use of tiles--and, no doubt, of other architectural embellishments in pottery--was encouraged by government enactments at various times. In the T´ang dynasty (618-906 A.D.),[441] in the districts south and west of the Yangtze, under the inspectorship of a man named Tan [Chinese], the inhabitants were ordered to use tiles on their houses in place of wood in order to lessen the risk of fire; kilns were erected to provide the tiles, and those who were too poor to carry out the alterations by themselves received State help. A somewhat similar but more important edict was issued in the twenty-seventh year of Hung Wu[442] (1394), that bricks and tiles should be used in all the buildings in the capital, which was then Nanking, and that kilns should be set up every year on the _Chü-pao shan_ for their manufacture. It was not long after this that the famous "porcelain pagoda" was erected at Nanking,[443] the lower part of which was faced with white porcelain bricks, the remaining storeys with pottery with coloured glazes. Tile factories existed in all parts of China to supply local needs, and the few singled out for mention in the _T´u Shu_[444] were perhaps of more than usual importance in the Ming dynasty. They are Lin-ch´ing [Chinese] in the extreme west of Shantung; Su Chou [Chinese] in Kiangsu, on the east side of the lake T´ai-hu, and facing the potteries of Yi-hsing, which supplied tiles for the palaces and temples of Nanking; the neighbouring Ch´ang-chou Chên, and Yi-chên and Kua Chou in the Yang-chou Fu of the same province; Wu-Ch´ing Hsien [Chinese], in the district of Peking, where the potters asked for permission to make tiles for public use in 1574. The tile works at Liu-li-chü (mentioned on p. 200) date from the Yüan dynasty. They are also situated in the neighbourhood of Peking, but whether in the Wu-ch´ing Hsien or not, I have failed to discover.