Phases of the Moon and Eclipses 231 



FIG. 140. Diagram showing an eclipse of the moon. The eclipse is caused by 

 the earth's coming between the moon and the sun. 



Eclipses of the moon sometimes continue total for 

 about 2 hours. From the beginning to the end of 

 the eclipse may be twice as long a time. Almost every 

 year you have an opportunity to see one or two eclipses 

 of the moon without going away from home. 



Questions about eclipses of the moon. What color 

 is the moon when in eclipse? Does it become wholly 

 invisible? Why? Is the new moon ever eclipsed? 

 Why? When the moon is partly eclipsed, the line 

 separating the dark from the light part is always curved ; 

 does this fact give any evidence as to the form of the 

 earth? Why does the sun never come between the 

 moon and the observer? Why do not eclipses occur 

 every time the moon goes around the earth ? 



