WHAT THE FISH SEES 



eighty-three degrees. It is as if he saw out 

 through a port-hole surrounded by a mirror. 



The diagram (Figure 14) shows this clearly. 

 F represents a fish near the bottom. He can see 

 out till he reaches the line AF or A' F. Beyond 



98/e% Light Enters Water 



FIG. 14. DIAGRAM OF FISH'S WINDOW 



these lines he sees the reflected bottom. Suppose 

 there is an object at B. The fish can see this di- 

 rectly through the water in a straight line, but he 

 will also see this at B f reflected against the under 

 side of the surface. The same is true of an object 

 at A. A fly below the surface beyond A or A' is 

 seen directly and also its reflection against the 

 surface. 



Light entering the water at different angles does 

 [ 49 ] 



