Calculating and Mapping the Disposition of Future Heavens: Ferdinand Verbiest’s Weather Forecasting and Its Termination During the Qing Court (1669–1680)

After the resurgence of Jesuit astronomy in 1669, the Flemish Jesuit missionary Ferdinand Verbiest (1623–1688) became the de facto head of the Astronomical Bureau in Qing China. Following the actions of the Italian priest Matteo Ricci (1552–1610) and of the German astronomer Johann Adam Schall von Bell (1591–1666), Verbiest mainly focused on weather forecasting to substitute Chinese traditional astrology with European natural astrology (how planetary motions affected the weather, disease, and agriculture), thereby disseminating his religious beliefs via Western mathematical science. Meanwhile, a series of strategies were mobilized to boost the credibility of this craft, including claiming its technical superiority based on actual celestial positions and calculations, masking the uncertainties with “approximate agreement” (the widening of the acceptable range), and dedicating mathematical instruments for a deep understanding. However, due to sudden political changes and Emperor Kangxi’s (1654–1722) criticism, Verbiest was forced to compromise on the public astrological discourse. Eventually, as the very speculative nature of his craft became apparent, the authorities declared the end of natural astrology and the full restoration of Chinese astrology. Verbiest’s story broadens the current picture of the calendrical and astrological reforms led by Jesuit scientists in China and provides a wider framework to analyze the global spread of Jesuit science and belief.