w 



MARE 



-'^'"''NUBIUM 



OCEANUS 



TRANQUILLITATIS MARE\ 



MARE VAPORUM 



CRISIUM 



.f^'JPROCELLARUM 



MARE 



Qfirnocharif 



FIG. 17. A MAP OF THE CHIEF PLAINS AND CRATERS OF THE MOON 



The plains were originally supposed to be seas: hence the name " Mare." 



Eart 



af" of Meteors 





FIG. 1 8. A DIAGRAM OF A STREAM OF METEORS SHOWING THE 

 EARTH PASSING THROUGH THEM 



