Reputed Chinese author of a ninth-century work entitled "Classified Essentials of the Mysterious Tao of the True Origin of Things," which contains an important early description of a type of Chinese gunpowder. The author warns that the substance is dangerous, causing serious burns if mixed incorrectly, and that the experimenter should exercise extreme caution.
"Cheng Yin." Science and Its Times: Understanding the Social Significance of Scientific Discovery. . Encyclopedia.com. (April 21, 2019). https://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/cheng-yin
"Cheng Yin." Science and Its Times: Understanding the Social Significance of Scientific Discovery. . Retrieved April 21, 2019 from Encyclopedia.com: https://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/cheng-yin