Hand-books of Natural Philosophy and Astronomy: Optics

already explained angle of incidence angle of refraction apparent magnitude appear axes centre chromatic circular colour concave reflector consequently convex lens corresponding crystal curved diameter diminished direction disc distance distinct vision diverging double convex double refraction effect equal extreme eye glass eye piece focal length foci focus F focus of incident greater illuminated inch incident rays index of refraction instrument intensity lenses less luminous point magnifying power manner medium microscope motion moved object glass object piece observer opaque optic axis parallel rays pencil of rays perception perpendicular phenomena placed plane of polarisation plano-convex lens plate position principal focus prism produced proportion radii radius reflected rays reflecting surface refracting power refrangibility rendered represented in fig retina right angles screen secondary pencil seen side sine space spectrum spherical aberration spherical reflector supposed telescope tion tourmaline transmitted transparent tube vertex vertical violet visual magnitude yellow