ASTRONOMY. 



SECT. VII. 



MOTION OF THE MOON. 



119. THE Moon, next to the sun, is the most 

 remarkable of all the heavenly bodies, and is 

 particularly distinguished by the periodical 

 changes to which its figure and light are sub- 

 ject. These changes are called the PHASES of 

 the Moon. 



Modb curvata in comua, moda &qua port zone divisa, 

 modb sinuata in orbem, maculosa, eadtmque subito 

 pr&nitenS) immensa orbepleno, et repente nutta % &c. 

 PLIN. Hist. Nat. lib. 11. cap. 9. 



120. At the time when the moon is due south, 

 about midnight, her disk is an entire circle, sub- 

 tending an angle not much different from half a 

 degree. On the next night, she comes later to 

 the meridian by about 4.8 minutes, and the west- 

 ern part of her disk is no longer bounded by a 

 circle, but by an elliptic line ; and this line, 

 .every subsequent night, is seen to encroach 

 more on the luminous pait, UU on the seventh 



night, 



