326 



WELLS'S NATURAL PHILOSOPHY. 



What is the White light, as emitted from the sun, or 

 wMte''iight'? °^ fj'oni any luminous body, is composed of seven 

 different kinds of light, viz., red, orange, yel- 

 low, green, bhie, indigo, and violet. 



What is the Thc scven different kinds of light produce 

 originofcoior? ^^^^^^ different colors, viz., red, orange, yellow, 

 green, blue, indigo, and violet. These seven colors are 

 called primary colors, since by the union or mixture of 

 some two or more of them, all other colors, or varieties of 

 color are j^roduced. 

 How is light The separation of white light into its sev- 



auaiyzed? ^^^^ parts is cffccted by means of a prism. 

 When a ray of white light is made to pass through a 

 prism, each of the seven rays of which it is composed 

 are refracted, or bent out of their course differently, and 

 form on an opposite screen or wall an image composed of 

 bands of the seven different coloi's. 

 What is the 686. The image formed by a ray of white 



Spectrum? ijght passiug througli a prism, is called the 

 Solar, or Prismatic Spectrum. 



Fig. 268. 



The separation of a ray of solar light into different colored rays, by refrac- 

 tion, is represented in Fig. 268. A ray of light, S A, is admitted through 

 an aperture in a shutter into a darl^ened chamber, and caused to fall on a 

 prism, P. The ray thus entering would, if allowed to pass unobstructedly, havo 

 moved in a straight line to the point K, on the floor of the room, and thero 



