•72 The Life Story of the Fish 



the line FX in Diagram D is bent at X and proceeds in the 

 direction XM. Light going i-'rom F to X' is bent at X' and 

 continues along the horizontal X'H. The angle FX'H is 

 more acute than the angle FXM. If, now, light travels from 



Diagram E 



F to Y, the angle at which it approaches the surface is even 

 sharper than that made by FX', and the angle through which 

 it is bent must be even sharper than the angle FX'H. The 

 result is that it is bent back beneath the surface, and never 

 gets out at all. This is total refraction. It is the same thing 

 as reflection, for if we reverse our directions and consider 

 the light traveling from an object at W toward Y, we find 



