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The colour’d image of the Sun

Image of the title page of Opticks

RB/2812  - Opticks, or a treatise on the reflexions, refractions and colours of light / Sir Isaac Newton, 1704

When Trinity College, Cambridge, temporarily closed in 1665 due to the Great Plague, one of the university’s less distinguished students continued private studies at his home. His unorthodox experiments would lead to breakthroughs in our understandings of calculus, optics, and gravity. That student, Isaac Newton, went on to become one of the most well-known and influential scientists of our time.

Newton is probably best known for his insights into the law of gravitation, but his studies also laid the foundation for modern physical optics. He published these findings in his second major scientific work, Opticks, or a Treatise on the Reflexions, Refractions and Colours of Light in 1704. The State Library has acquired a beautiful first edition of this important scientific work, bound in contemporary panelled calf and containing 19 engraved plates of mathematical diagrams.

Unlike Newton’s previous work, Principia, Opticks is written entirely in English prose, requiring neither knowledge of Latin nor advanced mathematics to understand the content. This resulted in Opticks reaching a popular audience and becoming the authoritative work on light and colour.

Opticks covers a range of topics – the composition of the rainbow, the colour wheel, Newton’s rings, refraction of crystals, friction, heat and electricity. Newton championed the use of empirical observation and the scientific method, describing his experiments in detail: 

In a very dark Chamber, at a round hole, about one third Part of an Inch broad, made in the Shut of a Window, I placed a Glass Prism. 

He observed that when the white light of the sun passed through the prism it broke into a spectrum of colours. He concluded that white light must be made up of a compound of primary colours travelling in a straight line and described this effect as ‘the colour’d image of the Sun’. Before Newton’s breakthrough, it was generally believed that light was pure, with colour originating from other matter.

Opticks joins works by Galileo Galilei, Robert Hooke and Charles Darwin in the Library’s collection of first editions of influential scientific works.   

Image of diagrams

Plate depicting diagrams - Book I, Plate I, Part I

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