Treatise on Light

work by Huygens

Also known as: “Traité de la lumière”

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July 16, 2026

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Christiaan Huygens's Treatise on Light (1690) proposed the first detailed wave theory of light. This work explained the laws of reflection and refraction based on the principle that light travels as waves. Huygens's principle states that each point on a wave front acts as a source of secondary spherical wavelets, and the new wave front is the envelope of these wavelets. This theory provided a mechanical explanation for light's behavior, contrasting with Isaac Newton's corpuscular (particle) theory, which suggested light particles were attracted to denser media. While Newton's particle theory dominated for a time, later experiments by Thomas Young and Augustin-Jean Fresnel in the 19th century provided strong evidence for light's wave nature.1234

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Christiaan Huygens
…Traité de la Lumière (Treatise on Light), already largely completed by 1678, was also published in 1690. In it he again showed his need for ultimate mechanical explanations in his discussion of the nature of light. But his beautiful explanations of reflection and refraction—far superior to those of Newton—were…
Read More
…Traité de la Lumière (Treatise on Light), already largely completed by 1678, was also published in 1690. In it he again showed his need for ultimate mechanical explanations in his discussion of the nature of light. But his beautiful explanations of reflection and refraction—far superior to those of Newton—were…
Read More