Houqi (waiting for qi, the active principal of life. A set of standard pitchpipes, each corresponding to a specific calendar period, was filled with ashes and buried in a sealed chamber; when the sun entered the second two-week period of a given month the seminal force of qi was supposed to rise and expel the ashes from the pipe that matched the calendar period.) was a technique employed by Chinese authorities in the fourteenth century to determine the onset of spring by measuring the emanations of
Unfortunately, the method failed to produce the desired results, and a great deal of discussion over the millennia as to what kind of soil to use, where to place the pitchpipes, and so on, failed to improve it. Ultimately the great music theorist Zhu Zaiyu (朱載堉, 1536–1611) criticized houqi as a poor example of scientific method.
This according to “Origins of the controversy over the houqi method (候气法疑案之发端)” by Tang Jikai (唐继凯) in Jiaoxiang: Journal of Xi’an Conservatory of Music (交响：西安音乐学院学报), vol. 22, no. 3:101 (fall 2003), pp. 27–31. Above, a calligrapher’s rendition of the Chinese character for qi.