John Stuart Reid's site keeps the most complete popular chronology of the field in one place: Leonardo and Galileo noticing dust on vibrating surfaces, Hooke's flour in a glass vessel, Chladni's plates, Faraday's crispations, Margaret Watts-Hughes and the eidophone, Hans Jenny coining the term, and then the CymaScope itself, presented as an instrument that renders sound as an analogue image in water.
As a set of names, dates and pointers it is genuinely handy, and the instrument does what it says: it makes a repeatable, photographable water surface pattern from an audio input.
The framing is where care is needed. The page moves without a break from documented experiments into talk of generative archetypes underlying life, of sound acting on consciousness, and of cymatics as a route to universal principles. None of that follows from the imaging, and the wider site extends the same approach to Egyptology, haematology and quantum physics. Use it as an index, not as evidence.