PURE AND REFLECTED LIGHT 



19 



higher in the evening sky and gets out of the 

 range of this heavy air lying along the earth, 

 the disk apparently grows smaller and becomes 

 clearer in light. The red and orange fade out, 

 and we see what is called the " yellow moon." 

 It grows still fainter as it rises toward the zen- 

 ith and the earth's atmosphere clears and cools ; 

 and when in the morning hours it sinks into 

 the west, the disk is whitened and apparently 

 shrunk in size. There is little color demonstra- 

 tion as it nears the horizon again. It is cool 

 and silvery, seldom red or yellow, and slips 

 from view usually unnoticed. 



Moonlight is, of course, the light of the sun 

 reflected from the moon. It is not reflected 

 from a bright surface like water (there is no 

 water on the moon) but from dull surfaces like 

 rock ; and as a result the reflection is many de- 

 grees feebler than its cause. Yet the moon has 

 some surface gleam about it and is hardly like 

 an illuminated transparency hung in the air. 

 By comparison with the sun it has no sharp 

 shafts and is so feeble that when sun and moon 

 are both above the horizon the latter attracts no 

 attention whatever ; but after the sun has gone 

 down and the moon rising in the east mingles its 

 light with the twilight of the west, it makes a 



