Heavenly Clockwork: The Great Astronomical Clocks of Medieval China

anaphoric astronomical clock astronomical instruments axle balancing lever bronze Bureau of Astronomy celestial globe century A.D. Ch'i Ch'ien Chang Hêng Chang Ssu-Hsün Chêng chih Chin China Chinese Ching Chou chung clepsydra clockwork demonstrational armillary sphere device diurnal motion double-hours drum dynasty ecliptic emperor equatorial escapement gear-ring gear-wheel gnomon Han dynasty heavens Hêng's horological Hsiang Hsiao Hsin Hsü Hsüan I-Hsing imperial indicator-rods invention jacks Jesuits Kêng Hsün kuan kuei later Liang Ling-Tsan Maspero Matteo Ricci mechanical clocks mechanised Ming moon motion Needham night-watches noria Palace Peking period quarters reign-period A.D. ring rotation scoops shaft Shang Shen Shen Kua shui sighting-tube stars steelyard striking clock Su Sung Sung dynasty Sung Shih Sung's clock T'ang t'ien tank Taoist time-keeping Tsêng Tsung upper Wang water-clocks water-power water-wheel Wên wheel Yuan