THE SOLAR SYSTEM 319 



our clouds hide it, the moon has no clouds in its sky, 

 no atmosphere for them to float in, no water upon its 

 surface to make them. The moon is an old world. Its 

 face is wrinkled and marked with many mountains, 

 all of them sharp and ragged. There is no running 

 water to smooth the sharply wrinkled surface; no 

 trees or shrubs to make it beautiful; no air to soften 

 all the outlines and temper the fierce glare of the sun, 

 which shines steadily upon it. 



Yet once, they tell us, there was water upon the 

 moon, for the dried-up seas have left their marks. 

 Those are what make the pictures that we see in the 

 moon. Some see a man's face; some, a man shooting; 

 and some, the face of a woman with hair rippling over 

 her shoulders. But when we look through a telescope 

 or even through an opera glass, the man's face and 

 all the other pictures are seen no more. We see in- 

 stead vast empty beds of dried-up oceans and the 

 peaks of mountains scattered over the surface. Dead 

 volcanoes we believe these to be, but far larger and 

 higher than any volcanoes that we have on our earth. 



The moon is our nearest neighbor among all the 

 heavenly bodies. It is called our satellite, because it 

 revolves around the earth while the earth revolves 

 around the sun. 



Besides the planets, which, with their satellites or 

 moons, revolve in regular order around the sun, 

 there are those wonderful objects that we call comets. 

 These also travel about the sun. Did you ever see a 

 picture of a comet? It is like a star with a long, 

 sweeping tail of light. The larger comets do not 

 often visit us, but when they do come they make a 



