Die Lehre von den Tonempfindungen, als physiologische Grundlage für die Theorie der Musik - Helmholtz, Hermann von 1821-1894 (Braunschweig Vieweg, 1877)
Hermann von Helmholtz was one of the last great polymaths of the 19th century. He built bridges between medicine, physics and chemistry. With his book "Die Lehre von den Tonempfindungen", published in 1863, he created the basis for the scientific analysis of sounds that is still relevant today. (https://www.deutschlandfunkkultur.de/hermann-von-helmholtz-und-seine-lehre-von-den-100.html)
Keywords: 19th Century (1801-1900); Music theory; Timbre; Sound; Chord; Tonality