186 
NATURE FOR ITS OWN SAKE 
The angle 
of reflec- 
tion, 
We are looking down upon the bush and see 
sunlight upon its green leaves ; but the reflec- 
tion shows us that under-portion of the bush 
which is in shadow. 
The rule governing our perception of reflec- 
tions is a familiar one: The angle of reflection 
is always equal to the angle of incidence. Prac- 
tically applied to our illustration, this means 
that standing twenty feet above the bush and 
fifty feet back from it, we see in reflection just 
what we should see in the original did we stand 
twenty feet delow the bush and fifty feet back 
from it. Again, if standing twenty feet above 
the surface we can see a portion of a mountain- 
peak reflected in the water, then we could see 
just that much of the peak itself if twenty feet 
below the surface. Every Swiss tourist has seen 
Mt. Blanc mirrored in the Lake of Geneva, 
though the two are some forty miles apart. 
The reason is that Mt. Blane is some three miles 
high. By increasing our height we see less of 
the reflection in proportion, as by increasing 
our depth we see less of the original. At the 
bottom of a well, looking up, we should be able 
to see only the sides of the well and the sky ; if 
at the top of the well, looking down, we should 
see the same things in reflection. 
