Oldal 32 [32]
I 2 LIGHT AND WATER
all of the real house which is above D (D being the
corresponding point to d) will appear in the reflexion
and no more. But if we ascend to E the image of the
house is entirely hidden by the bank B, and our view
of the image as a whole is limited by the line B/, so
that we only see reflected the small portion of the cliff
above the point F.
This seems to be the simplest way of regarding
reflexions. But some may perhaps find the following
preferable. Instead of imagining an inverted image,
let the observer suppose himself able to be lowered ver¬
tically from the point where he ts standing to a position
as far beneath the surfaceas hers actually abovert. The
veflexton that appears to him on the water ts identical
with the view he would get of the object from this wm¬
aginary point, this view being, of course, inverted. This
has already been pointed out with regard to Fig. 3,
in which the view of the image from E 1s similar to
the direct view of the candlestick from e. So also in
Fig. 4 the reflexions seen from C and E are similar
to the direct views of the actual landscape from ¢ and
e respectively, c and e being imaginary points verti¬
cally as far beneath the level of the water as C and
E are above it. Again, if Fig. 7 (page 15) is turned
upside down, we have the “perverted” view of the
house that we should get if it were possible to look at
it from a point as far below the surface of the water in
a vertical line as that from which the picture is taken.
This method is the more convenient for the pur¬
poses of a diagram, as it obviates the necessity for
drawing the image. For example: suppose a man
standing at E (Fig. 5) to see the top of the willow,