Page 51 [51]
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.