The Harvest Moon. 319 



that equal portions of it always rise or set at 

 equal times. Consequently, if the moon's motion 

 were equable, and in the equinoctial, at the rate 

 of 12 deg. 11 min. from the sun every day, as 

 it is in her orbit, she would rise and set about 

 49 minutes later every day than on the pre- 

 ceding; for 12 deg. 11 min. of the equinoctial, 

 rise or set in about that time in all latitudes. 



But the moon's motion is so nearly in the 

 ecliptic, that we may consider her for the pre- 

 sent as moving in it. Now the different parts 

 of the ecliptic, on account of its obliquity to the 

 earth's axis, make very different angles with the 

 horizon as they set or rise. Those parts or signs 

 which rise with the smallest angles set with the 

 greatest, and the contrary. In equal times, 

 whenever this angle is lost, a greater portion of 

 the ecliptic rises than when the angle is larger; 

 as may be seen by elevating the pole of a globe 

 to any considerable latitude, and then turning it 

 round its axis. Consequently, when the moon 

 is in those signs which rise or set with the 

 smallest angles, she rises or sets with the least 

 difference of time; and with the greatest dif- 

 ference in those signs which rise or set with the 

 greatest angles. 



In northern latitudes, the smallest angle made 

 by the ecliptic and the horizon is when Aries 

 rises, at the time when Libra sets ; the greatest 

 when Libra rises at the time Aries sets. From 

 the rising of Aries to the rising of Libra the 



