This chapter examines the influence of colour-tone analogies, used both in ancient Greek natural philosophy and modern science, on the emergence of the invention of ‘colour organ’ instruments from the early 18th to late 19th centuries. The instruments were typically designed around a music keyboard mechanism, such as a harpsichord or organ. The keys of the keyboard controlled the display of colour, and colours corresponded to the notes of the musical scale. Initially, these inventions were perceived as demonstrating and supporting the science of the colour-tone analogy. Yet each of these inventors also envisaged something more than a colour-tone analogy for their respective instrument invention, recognizing the unique aesthetic potential and possibility for the presentation of a mobile colour with a music performance. This chapter argues that as the 19th century progressed, inventors believed that such was the power of the combination of colour and music via the design of a performance instrument to facilitate it that it constituted a new art of colour music. Inventors devised their own systematic approach to how such a colour music could be made possible in the physical design and in what way the colour is in correspondence with musical parameters and information.