256 SCIENCE OF COMMON THINGS. 



Effects of a prism In separating the rays of light. 



the top of the prism, and the red will remain at the 

 bottom. 



Violet 



Indigo. 



Blue? 



Green. 



Yellow. 



Orange. 



Ked. 



Fig. by. 



This separation of a ray of solar light into different colors, by refraction, 

 is represented in Fig. 69. A ray of light, A, is admitted through an 

 aperture in a window-shutter into a darkened chamber, and caused to fall 

 on a prism, P. The ray thus entering would, if allowed to pass unob- 

 structedly, have moved in a straight line to the point K, on the floor of 

 the room ; but the prism being so placed that the ray may enter and quit 

 it at equal angles, it will be refracted in such a manner as to form on the 

 opposite side of the room an oblong image called the solar spectrum, 

 divided horizontally into seven colored spaces or bands of unequal extent, 

 succeeding each other in the order represented: red, orange, yellow, green, 

 blue, indigo, viokt. 



1678 Are the colored rays, once separated and refracted from the 

 prism, capable of being analyzed by refraction again ? 



They are not, and are hence designated as primary 

 colors. 



1679 If the seven different colors as separated by the prism be again 

 collected together, what will they form ? 



White light. 



1G8O To what is the great brilliancy of the diamond and other precious 

 stones due ? 



To their power of refracting light ; they are also 

 artificially cut in such a manner as to form a series of 

 prisms,, which separate the rays of light falling on 

 mem into their component colored rays. 



1GS1 What is a rainbow f 



The rainbow is a semicircular l>and or arc, composed 



