BOOK XVIII. Lxxv. 322-325 



it, as well as felling tinibcr and the other operations 



which we have specified in their proper places. Nor 



is the observation of the moon specially easy, and we 



liave already spoken of it in \^olume II ; biit to give ^^- ^^ w- 



what even countrymen may be able to understand : 



whenever the moon is seen at sunset and in the Phases, etc, 



earlier hours of the night, she will be waxing and ''^"'* """"' 



will appear to be cut in half, but when she rises 



at sunset opposite the sun, so that sun and moon 



are visible at the same time, then it will be fuU 



moon. When she rises with the sunrise and withholds 



her hght in the earher hours of the night and prolongs 



it into daytime, she will be waning and will again 



show only half; but when she has ceased to be 



visible she is in conjunction, the period designated 



' between moons '. During the conjunction she will 



be above the horizon as long as the sun is and during 



the whole of the first day, on the second day ten and 



a quarter twelfths of an hour of the night," and 



then on the third day and on to the 15th with the 



same fractions of an hour added in progression. 



On the 15th day she will be above the horizon all 



iiight and also below it all day. On the 16th she will 



remain below the horizon ten and a quarter twelfths 



of the first hour of the night, and she will go on adding 



the same fraction of an hour every day in succession 



until the period of conjunction, and will add from the 



day-time to the last parts of the night above the 



horizon as much as she subtracts from its first parts 



when below the earth. She will complete thirty 



revolutions in alternate months but subtract one from 



that number every alternate month. This will be 



the theory of the course of the moon ; that of the 



winds is somewhat more intricate. 



393 



