Opticks

Optics by Isaac Newton is a treatise on light and the science of reflected light, refracted light, and colors. The book analyzes the fundamental nature of light using the refraction of light with prisms and lenses, the diffraction of light by closely spaced sheets of glass, and the behavior of color mixtures with spectral lights or pigment powders. Excerpt: "Exper. 1. I took a black oblong stiff Paper terminated by Parallel Sides, and with a Perpendicular right Line drawn cross from one side to the other, distinguished it into two equal Parts. One of these parts I painted with a red color and the other with blue. The Paper was very black, and the Colors intense and thickly laid on, that the Phænomenon might be more conspicuous. This Paper I viewed through a Prism of solid Glass, whose two Sides through which the Light passed to the Eye was plane and well polished, and contained an Angle of about sixty degrees; which Angle I call the refracting Angle of the Prism."