PIT RE AND REFLECTED LIGHT 



15 



the surface of the earth, they pass through 

 many miles of this heated dust-and-moisture- 

 laden air. When they reach our eyes they tell 

 the oft-told tale of the brilliant sunset. The 

 pale grays and silvers of the dawn, produced by 

 the sun's rays coming to us through a cleared 

 and cooled atmosphere, have now changed to 

 the golds and scarlets of the evening, produced 

 by the rays coming to us through a heated and 

 a thickened atmosphere. So dense is the air at 

 times that the shafts of the setting sun may be 

 distinctly seen radiating up the sky like the 

 spokes of an enormous fiery wheel ; and again 

 at other times the air may be so thick that it 

 obscures the sun's rays, and we can see the red 

 disk go down almost without a flash of light as 

 though its own heat had consumed it. 



The glare and heat of sunset colors are per- 

 haps more apparent than real. The same sun 

 at the time it looks red to us may show the 

 yellow of noon and the white of dawn to the 

 people and the lands lying to the west of us. 

 We are looking from a land of shadow toward 

 one that is still in full sunlight, and the bright- 

 ness of the sky-color is great by contrast. The 

 colors and combinations of colors that we see 

 on the western sky and clouds at sunset and 



The tunset. 



Red tun 



disks. 



Suntet 

 color*. 



