Discourse on the Method
"La dioptrique" (in English "Dioptrique", "Optics", or "Dioptrics"), is a short treatise published in 1637 included in one of the "Essays" written with "Discourse on the Method" by Rene Descartes. In this essay Descartes uses various models to understand the properties of light. This essay is known as Descartes' greatest contribution to optics, as it is the first publication of the Law of Refraction.