For demonstrating that white light is composed of all the spectral colours through the additive mixing of the colours. Comprising a multicoloured circular disc having sectors of various spectral color in proper proportions. On rotating the disc at sufficient speed, all the colours will be observed to disappear by merging into a single white colour. The disc has a friction pulley at the back touching the driving wheel with a handle. Complete assemblymounted on a stable base.
Newton's Colour Disc, smaller economical model.