LIGHT. 23 



pie in its nature, but it may be proved by experiment 

 that every beam of white light such as we receive from 

 the sun is made up of rays of different colors. 



37. This maybe done by holding a prism 



How is- its . 



composition in the sun and al- 

 P roved? lowing the light 



to pass through it and fall 

 upon an opposite wall or 

 screen. A beautiful parti-colored spot will be produced, 

 called the solar spectrum. The beam of light which 

 enters the prism is separated by it into rays of seven dif- 

 ferent colors. The experiment, if performed in a dark 

 room, into which light is admitted through a very small 

 opening, is extremely beautiful. 



38. The rays, before entering the prism, 



How does re- . r 



fraction de- passing along together parallel with each 

 compose light? other? form white H ht . but on entering 



the glass and emerging from it, each of them is 

 refracted or bent out of its course in a different degree, 

 and they are thus separated, and made to appear with 

 their own colors. Why one ray is refracted more than 

 another is not known. The above experiment proves 

 it to be a fact, and this is all our knowledge on the 

 subject. 



Do lenses de- 39. LENSES DECOMPOSE WHITE LIGHT 



compose light? AND RE COMBINE THE RAYS. This separation 

 of white light into colored rays occurs always when 

 light passes through a prism ; but, for the sake of sim- 

 plicity, this fact was left out of consideration in para- 

 graph 29, the object in that place being simply to 

 show the general direction of the light as it passes 



