366 LIGHT. 



A. Because the pupil (which con- 

 tracted in the bright room) does not 

 dilate instantaneously ; and the contracted 

 pupil is not able to collect rays enough 

 (from the dark road or street) to enable 

 us to see before us. 



Q. Why do we SEE BETTEB, when we get USED 

 to the dark ? 



A. Because the pupil dilates again, 

 and is able to gather together more rays; 

 in consequence of which, we see more 

 distinctly. 



Q. If we look at the SUN for a few moments, 

 why do all OTHER things appear DARK ? 



A. Because the pupil of the eye 

 (which was very much contracted by 

 looking at the sun) is too small to collect 

 sufficient rays from other objects, to enable 

 us to distinguish their colours. (See 

 "accidental colours.") 



Q. If we watch a bright FIRE for a few 

 moments, why does the ROOM seem DARK ? 



A. Because the pupil of the eye 

 (which was very much contracted by 

 looking at the fire) is too small to collect 

 sufficient rays from the objects around, 

 to enable us to distinguish their colours. 



