PURE AND REFLECTED LIGHT 



lost to us in the upper air, and that which 

 finally comes on down to the earth has to our 

 eyes a prevailing whitish, reddish, or yellow 

 tone, dependent upon the density of the air. If 

 we could sweep away our atmosphere entirely, 

 the light would appear bluish and the sun itself 

 violet- blue.* There is a predominance of vio- 

 let and blue in sunlight, but the waves of these 

 colors being the shortest and weakest in travel- 

 ling power, are the first ones to be caught and 

 absorbed by the upper atmosphere. Held in 

 check, entangled as it were, quantities of them 

 are massed above us, making what we call " the 

 blue sky." The yellow and red waves, having 

 greater length and power than the blue ones, 

 penetrate the atmosphere deeper and come to 

 us with the tale that the sun is yellow or red 

 or, in combination with other colors, white. 



But the tale is deceptive. Sunlight in its 

 entirety appears whiter and then bluer, in pro- 

 portion as we rid ourselves of our atmospheric 

 lens ; and the sky itself grows darker from the 

 non-diffusion of the sun's rays. An ordinary 

 rain-storm that clears the atmosphere will tem- 



* This is the conclusion of Professors Langley, Young, 

 and other scientists. If seen from a distant world, our 

 sun would appear as one of the blue stars. 



Violet-blue 

 sunlight. 



