CHAPTER XXVII 

 REFRACTION 



Bent rays of light. A straw in a glass of lemonade seems to 

 be broken at the surface of the liquid, the handle of a teaspoon 

 in a cup of water appears broken, and objects seen through a 



glass of water may seem 

 distorted and changed in 

 size. When light passes 

 from air into water, or 

 from any transparent sub- 

 stance into another of dif- 

 ferent density, its direction 

 is changed, and it emerges 

 along an entirely new path 

 (Fig. 123). We know that 



FIG. 123. A straw or stick in water seems light rays pass through 



glass, because we can see 



through the window panes and through our spectacles; we 

 know that light rays pass through water, because we can see 

 through a glass of clear water; on the other hand, light rays 

 cannot pass through wood, leather, metal, and the like. 



Whenever light meets a transparent substance obliquely, 

 some of it is reflected, and some of it passes onward through the 

 medium; but the latter portion passes onward along a new 

 path. The ray RO (Fig. 124) passes obliquely through the air 

 to the surface of the water, but, on entering the water, it is 

 bent or refracted and takes the new path OS. The angle AOR 





