OCR
REFLEXIONS IN RIPPLED WATER 27 four different positions, lying horizontally on a table. There is a picture FG hanging on the wall to the left. If the eye is placed at E, we see reflected at A the base, at B the middle, and at C the top of the picture. At D we shall see only the bare wall above. — eee NE TT EI üg a = In other words, the reflexion of the picture extends the opposite direction, 7.e., from the eye to the object instead of from the object to the eye. We have shown how a ray of light is reflected at a plane surface in obedience to a certain law. For instance, in Fig. 2, page 6, the , ray PF is reflected at F, so that it reaches the eye at E; that is to say that if we look from E towards F we shall see by reflexion the point of light P. So that, if we call EF our “Zine of vision,” we may say that the line of vision is reflected at the point F on the surface of the mirror and proceeds after reflexion, in obedience to the law already stated, in the direction FP. By adopting this convention, the discussion is much simplified.