The book “Self-portrait of K’ang-hsi” by Jonathan D. Spence holds some interesting information.
After reading the book I had learned that the Emperor Kangxi was a man who expressed himself with openness and had an exuberant curiosity and a great desire for information.
His many interests included Geometry, mechanics, astronomy, cartography, optics, music, algebra and medicine.
He developed the palace memorial system, a form of confidential communication in which officials wrote directly to him, rather than having their messages mediated through some branch of the bureaucracy, and he answered them himself. Many of these memorials, with Kangxi comments have survived.
He say of a particular person “Ch’a Shenhsing has bad stomach trouble, so I sent him some of my Western medicine. Their wine is a tonic.”
I also learned that Kangxi took western brandy and cinnamon to stop his heart palpitations.
There was also a recipe in which Kangxi asked Wang Chih for the exact formula, which had ten main ingredients. Kangxi gave the formula to a doctor Chang Lu who revised the formula and it ended up with nine main ingredients.
Ts ui-Hsien pills
Ginseng – Hongshen
Lotus Root – Lian Ou
Oxlip – Gao bao chun
Raspberries – Fu pen zi
White lotus – Lian zi yin
Dog rose – Mei gui hua
Knot grass – Bian xu
Dogwood – Shan zhu yu
White honey – Bai fengmi
Here we have confirmation that Kangxi was in the habit or writing notes and passing them on. He was also using spirits with herbs and he was messing with formulas.