20 OPTICAL OUTLINES. parallel to the principal axis, and, therefore, passing after refraction through the principal focus/'. These two rays (and all others which pass through the lens from the point a) will meet at a, the conjugate focus of a. Similarly the Fig. 12. … Real inverted image formed by a convex lens. focus of the point b is found, and the real inverted conju- gate image of a b is formed at a b. The relative sizes of a b and a b vary as their distances from the lens. If a & be so far off that its rays are virtually parallel on reaching the lens, its…
Eye · Color blindness
Internet Archive · Yale University, Cushing/Whitney Medical Library · Public domain (published before 1931). Free to use for anything.
