i68 



The Moon. 



A study of the motions of the moon makes a good beginning 

 toward a clear understanding of the apparent and real motions 

 of the sun, moon, and stars. 



On the first evening that the moon can be seen after " new 

 moon," have the pupils note how near it is to some star. Venus 

 may be in a good position near the moon. On tlie following 

 evening they are again to note its relation to this star. They 

 may make their notes by making a sketch of moon and star each 

 night. The changing shape of the illuminated part of the moon 

 is also to be noted each night. Soon the moon will be so far 

 from the star that it cannot well be used to mark the progress. 

 Then another star nearer to it, in its new position, may be used 

 as the mark. 



At first only these notes are to be taken. After the moon 

 has made considerable progress among the stars, inquiries maj' 

 be started as to what is taking place. Most, if not all of the 

 pupils will know that the moon, in common with the sun and 

 with the myraids of stars among which the sun and moon move, 

 rises in the east and sets in the west daily, and they will know that 

 the cause of this apparent motion is the earth's revolution. But 

 most o£ tliem will be surprised to find that the moon moves east 

 among the stars. These observations may be carried on and dis- 

 cussed by thepuKiils until they make out for themselves tb.at this 

 is the motion of the moon around the earth. 



The time of revolution may be determined by noting the 

 date when the moon passes some "fixed star" until it passes 

 it again. 



If the pupils understand circles and degrees, a simple 

 apparatus can be arranged by which they can determine approxi- 

 mately the number of degrees it moves in every twenty-four 

 hours. 



