55 LENSES. D is a double concave lens. Parallel rays are divergent as if coming from the centre. E is a plano-concave lens. Parallel rays are also divergent, but the focus is at the circumference. … C and F are both concave-convex lenses : but in C the convex is the smaller circle and has the greater power, and the glass acts as a convex lens, and the rays are convergent (meet together).* In E it is the reverse, the concave has the smaller circle and the greater power, and the glass acts as a…
Light · Color · Optical illusions · Optics
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
