RAY, in Optics, a beam of light emitted from a radiant or luminous body. See LIGHT and OPTICS.
Inflected Rays, those rays of light which, on their near approach to the edges of bodies, in passing by them, are bent out of their course, being turned either from the body or towards it. This property of the rays of light is generally termed diffraction by foreigners, and Dr Hooke sometimes called it deflection.
Reflected Rays, those rays of light which, after falling upon the body, do not go beyond the surface of it, but are thrown back again.
Refracted Rays, those rays of light which, after falling upon any medium, enter its surface, being bent either
towards or from a perpendicular to the point on which they fell.