920 



Handbook of Nature-Study 



within the crater circle is level. Thirty-three thousand of these craters 

 have been discovered. And, too, on the moon, there are great plains and 

 chasms ; and all these features of the moon have been mapped, measured 

 and photographed by people on our earth. For a boy studying geometry, 

 the measuring of the height of the mountains of the moon is an interesting 

 story. 



But we could never in our present bodies visit the moon, because of one 

 terrible fact the moon has no air surrounding it. No air ! What does that 

 mean to a world? First of all, as we know life, no living thing animal or 

 plant could exist there, for living beings must have air. Neither is there 

 water on the moon; for if there were water there would have to be air. 

 And without water no green thing can be grown, and the surface of the moon 

 is simply naked, barren rock. If we were on the moon, we could not turn 

 our eyes toward the sun, for with no air to veil it, its fierce light would blind 

 us ; and the sky is as black at midday as at midnight, since there is no at- 

 mosphere to sift out the other rays of light, leaving the beautiful blue in the 

 sky ; nor is there a glow at sunset because there is no air prism to separate 

 the rays of light and no clouds to reflect or refract them. The stars could 

 be seen in the black skies of midday as well as in the black skies of night, and 

 they would be simply points of light and could not twinkle, since there is no 

 air to diffuse the sun's light and thus curtain the stars by day and cause 

 them to twinkle at night. The shadows on the moon are, for the same 

 reason , as black as midnight and as sharply defined ; and if we should step 

 into the shadow of a rock at midday we should be hidden as much as if we 

 had stepped into a well of ink, or put on the invisible cloak of fairy lore. 



f*"' - \^'i 



The moon's surface seen through a telescope, showing the craters Mercator and Cam- 

 panus. Note that the shadows give some idea of their height. 



Photo after Nasmyth. 



