NATURE FOR ITS OWN SAKE 



CHAPTER I 

 PURE AND REFLECTED LIGHT 



A PISH at home under some ledge of rock in 

 the depths of the sea, what does it know of sun- 

 light ? Doubtless the pupils of its eyes con- 

 tract and expand with the lights and shadows 

 that break across the hills and valleys of the 

 ocean world, but how dim must be those lights, 

 how densely dark those shadows ! A ray of sun- 

 shine passing through five hundred feet of wa- 

 ter is broken, deflected, almost extinguished ; 

 and the eyes that look upward toward the light 

 through that great green lens of wave can 

 gather but a faint glimmer of the truth. They 

 are focused for the ocean depths, and when the 

 fish is brought up to the open day the eyes are 

 instantly set, and stare without meaning. The 

 first flashing sunbeam doubtless shocks them 

 senseless. The truth when revealed is blinding, 

 and our sunlight is final truth to the fish. 



Knowledge 

 of light. 



