fraction by a thin lens the same for all rays incident at the same distance from the axis. 8. An ordinary lens is a segment of a sphere (plano- convex or plano-concave), or of two spheres whose centres are joined by the axis of the lens (biconvex or biconcave). 9. A lens is regarded as formed of an… … Prismatic elements of a convex lens. therefore, in accordance with § 5, refracting more, than /?, the angle of the prism nearer the axis. If two parallel rays, a and b, traverse this system, a will be more refracted
Eye · Color blindness
Internet Archive · Yale University, Cushing/Whitney Medical Library · Public domain (published before 1931). Free to use for anything.
