This excerpt, primarily from Isaac Newton's Opticks, details his foundational theories and experimental observations regarding light and color. Newton systematically presents definitions of light phenomena like refrangibility and reflexibility, and axioms governing refraction, including the law of sines. He explains how different colors arise from varying refrangibility and how white light is a composition of all colors, demonstrating this through prism experiments and the recombination of spectral hues. The text also explores the colors observed in thin transparent bodies (like soap bubbles) and thick plates of glass, attributing these to the varying thicknesses at which light is reflected or transmitted. Finally, it delves into broader philosophical inquiries about light's interaction with matter, the nature of heat, and the existence of an aetherial medium that influences gravity and light's behavior, concluding with reflections on the order and design in nature.