Formulae on curved forms, 1704.
© Science Museum / Science & Society Picture Library
Page of mathematical formulae from Newton's 'Opticks', (1704). Sir Isaac Newton (1642-1727) discovered that by refracting light through a prism white light was dispersed into its constituent colours. If one colour was selected and refracted through a second prism, no further colours were introduced, showing that colours were a property of light and not the prism.