150 



EXPERIMENTAL GENERAL SCIENCE 



the objects it strikes are always in line with the source of light 

 and the opening through which it comes. 



126. Reflection of Light. Though light travels in straight 

 lines, it may be easily diverted or reflected. A sunbeam may 

 be caught on a mirror and turned completely out of its 

 course. By a suitable arrangement of mirrors, its course 

 may be changed again and again. Were it not for the fact 

 that the direction of rays of light can be altered, our eyes 

 would be of little use to us, for most of our seeing is not by 

 direct light, but by light which has first fallen on some object 



FIG. 50. Angle of incidence is equal to angle of reflection. 



and by it has been reflected to the eye. More than this, 

 unless the object viewed is in direct sunlight, or in the light 

 from some other source of illumination, the light preceding 

 from it has been diverted more than once before it reaches 

 the eye. Rooms into which the sun does not shine during 

 the day are lighted by reflection from the clouds, from dust 

 in the air, from trees, buildings, and similar objects. Smooth 

 surfaces are the best reflectors because they turn back the light 

 uniformly. Objects with rough surfaces reflect the light in 

 many directions, each small irregularity acting as a separate 

 mirror, and thus a clear image is impossible. Whenever light 



