112 PLllsVs NATURAL HISTORY. [Book XVIII. 



at the moon's conjunction, and during the four days about 

 that period. It is generally recommended, too, to give an airing 

 to corn and the leguminous grains, and to garner them, towards 

 the end of the moon ; to make seed-plots when the moon 

 is above the horizon ; and to tread out the grape, to fell tim- 

 ber, and to do many other things that have been mentioned 

 in their respective places, when the moon is below it. 



The observation of the moon, in general, as already ob- 

 served in the Second Book, 59 is not so very easy, but what I 

 am about here to state even rustics will be able to comprehend : 

 so long as the moon is seen in the west, and during the earlier 

 hours of the night, she will be on the increase, and one half 

 of her disk will be perceived ; but when the moon is seen to 

 rise at sun- set and opposite to the sun, so that they are both 

 perceptible at the same moment, she will be at full. Again, 

 as often as the moon rises in the east, and does not give her 

 light in the earlier hours of the night, but shows herself 

 during a portion of the day, she will be on the wane, and one 

 half of her only will again be perceptible : when the moon has 

 ceased to be visible, she is in conjunction, a period known to 

 lisas " interlunium." 60 During the conjunction, the moon will 

 be above the horizon the same time as the sun, for the whole 

 of the first day; on the second, she will advance upon the 

 night ten- twelfths of an hour and one-fourth of a twelfth ; 61 

 on the third day, the same as on the second, and * * * so on 

 in succession up to the fifteenth day, the same proportional parts 

 of an hour being added each day. On the fifteenth day she will 

 be above the horizon all night, and below it all day. On the 

 sixteenth, she will remain below the horizon ten-twelfths of 

 an hour, and one-fourth of a twelfth, at the first hour of the 

 night, and so on in the same proportion day after clay, up to 

 the period of her conjunction ; and thus, the same time which, 

 by remaining under the horizon, she withdraws from the first 

 part of the night, she will add to the end of the night by 

 remaining above the horizon. Her revolutions, too, will 

 occupy thirty days one month, and twenty-nine the next, and 

 so on alternately. Such is the theory of the revolutions of 

 the moon. 



59 In Chapters 6, 7, 8 and 11. 



GO o r "between moons." The " change of the moon,'' as we call it. 



61 51 minutes. 



