LIGHT AND COLOR 359 



dust and smoke in the air has absorbed the other colors 

 and has transmitted one of these two. On the top of a 

 high mountain or on a clear day, or when the sun is high 

 overhead, the sky appears blue. When the particles of 

 matter in the atmosphere through which light is coming are 



TELESCOPE EQUIPPED WITH A SPECTROSCOPE 



It is with instruments like this that astronomers have been able to 

 determine the composition of the sun. 



very minute, blue is the color reflected. A blue sky in- 

 dicates a clearer atmosphere. 



Sometimes after a shower an arch appears in the heavens, 

 composed of beautiful colors; we call this a rainbow. In 

 this case the sunlight is broken into different colors by the 

 drops of water which still fall in the distance, just as it is 

 when passing through a prism. 



