Newton's optics. Coloured artwork of the English physicist Isaac Newton (1642-1727) conducting his famous experiment on light. He is using a prism to refract a ray of light from a hole in the shutters over a window. A white surface (far left) allowed Newton to observe that light splits into the different colours (spectrum) observed in rainbows. Newton failed to further split the colours, but later he remixed the colours using a lens and prism. Newton carried out this experiment while at Cambridge University, but the results were not known until he published the book Opticks in 1704. Newton is also famous for his general theory of gravitation, and for his mathematical discoveries.