48 4 



THE OUTGO OF ENERGY 



other words, a convex lens of 5 D must be placed 

 before the cornea in order to enable the eye with 

 ciliary muscle relaxed to see clearly an object 

 situated at the near point. 



The near point recedes as the lens becomes 

 harder with advancing age until about the seven- 

 tieth year, when R = infinity, and accommodation 

 is lost. 



RANGE OF ACCOMMODATION AT DIFFERENT 

 AGES 



OPHTHALMOSCOPY 



Reflection from Retina. 1. Copy the construc- 

 tion used to find the image of the point i formed 

 by the dioptric system C (page 457). Assume 

 that the image is itself luminous, and that rays 



