COMMON THINGS THE ALMANAC. 



will set at sunrise. It is a remarkable character, therefore, of 

 this arrangement that the position in which the illuminating 

 power of the moon is greatest is precisely that in which it is 

 present in the visible part of the firmament during the entire 

 night. 



86. After having been full, the moon still moving round the 

 firmament in the same direction, begins to overtake the sun, 

 and is now at less than 180 to the west of the sun ; and as it 

 advances from west to east, it approaches the sun at the rate of 

 12 per day; so that on the 22nd day it is only 90 west of 

 the sun. 



Between the 15th and 22nd days from conjunction, the dis- 

 tance of the moon west of the sun is less than 180, but more 

 than 90, and according to what has been explained in vol. iii. 

 pp. 36, 37, it is then gibbous, as shown in fig. 11, the semicircular 



Fig. 11. 



edge being turned towards the sun, that is, towards the east, and 

 the semi- elliptical edge towards the west. The moon now moves 

 with the enlightened edge foremost, contrary to what took place 

 before it was full. The unenlightened part, as before, is indicated 

 in the figure by the dotted line. 



Being more than 90 to the west of the sun, the moon must 

 now be on the west of the meridian at sunrise, and must therefore 

 have culminated before sunrise. In this position, therefore, the 

 moon is seen during the greater part of the night, and the early 

 morning. It is also faintly visible in the heavens after sunrise, 

 and until it sets, the sun's light not being sufficient to overpower 

 it altogether. 



On the 22nd day, the moon is 90 west of the sun, and is 

 halved (fig. 2, vol. iii. pp. 36, 37). This is called in the almanack 

 the LAST QUARTER. The moon rises at midnight and culminates 

 about sunrise. It is therefore visible between midnight and 

 sunrise in the eastern quarter of the heavens. After sunrise it 

 is still faintly visible in the western quarter until it sets, which 

 it does about the hour of noon. 



From the 22nd to the 30th day of the conjunction the moon 

 moves constantly nearer to the sun, being now a crescent the 

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