LIGHT 



231 



The Prism and Composition of White Light. If sun- 

 light be allowed to fall on a glass prism (Figure 209) and 

 the refracted rays be caught on a white screen, a beauti- 

 ful band of colors will be seen. These colors in their 

 order are violet, indigo, blue, green, yellow, orange, and 



FIG. 209. The prism separates white light into its constituent colors, 

 which are arranged as shown. 



red. The violet color is refracted or bent from its original 

 path the most ; the red color is refracted the least. From 

 this experiment it is evident that the white light from 

 the sun is composed of these several colors. The entire 

 band of colors is called the solar spectrum, and the process 



FIG. 210. A piece of paper placed between the prisms will show 

 the separated colors. 



of separating colors by refraction is called dispersion. 

 If the solar spectrum made by a prism is passed through 

 a similar prism in a reversed position (Figure 210), the 

 several colors will be reunited to form a single band of 

 white light. 



