This my little experiment to mix RGB colours mechanically.
James Clerk Maxwell developed a tool to trick the human brain. By spinning the right amounts of red, green and blue on a wheel, it seems like the colours are melting together to white. With this experiment he could prove that what we perceive as white is actually a mix of colours. And that there’s a difference of mixing colours in light (RGB) and colours in pigments (CMYK). (Source: https://designblog.rietveldacademie.nl/?p=68422)
In the 1860s, James Clerk Maxwell explored the use of three primary colors and realized that no additive combination of three primary colors can cover the entire gamut of perceivable hues. He showed that the set of primaries was not unique, but that spectral primaries more widely separated in wavelength could be used to produce a wider range of perceived hues. He also realized that with some subtraction, the entire gamut of perceived colors could be covered. Maxwell recognized that the chromaticity (hue and saturation) of a colored surface is relatively insensitive to the brightness. Maxwell’s work could be considered to be the basis for modern colorimetry. (Source: http://hyperphysics.phy-astr.gsu.edu/hbase/vision/colhist.html)