Opticks

A systematic experimental and mathematical investigation of light that defines rays and optical terms, states axioms and laws of reflection and refraction, and demonstrates how compound light separates into component colours by prismatic dispersion. The work reports precise experiments and geometric proofs for phenomena including angle relations, total internal reflection, and spectral composition, explains colour mixing and the homogeneity of simple lights, and interleaves propositions with practical procedures. It concludes with a series of questions and tentative speculations intended to guide further experiment and probe unresolved causal issues.