CONCERNING WEATHER SIGNS, 6-9 



Now the first point to be seized is that the various 

 periods are all divided in half, so that one's study of 

 the year the month or the day should take account 

 of these divisions. The year is divided in half by 

 the setting and rising of the Pleiad x : for from the 

 setting to the rising is a half year. So that to begin 

 with the whole period is divided into halves : and a 

 like division is effected by the solstices and equinoxes. 

 From which it follows that, whatever is the condition 

 of the atmosphere when the Pleiad sets, that it con- 

 tinues in general to be till the winter solstice, and, 

 if it does change, the change only takes place after 

 the solstice : while, if it does not change, it continues 

 the same till the spring equinox : the same principle 

 holds good from that time to the rising of the Pleiad, 

 from that again to the summer solstice, from that 

 again to the autumnal equinox, and from that to the 

 setting of the Pleiad. 



So too is it with each month ; the full moon and 

 the eighth 2 and the fourth days make divisions into 

 halves, so that one should make the new moon the 

 starting-point of one's survey. A change most often 

 takes place on the fourth day, or, failing that, on the 

 eighth, or, failing that, at the full moon ; after that the 

 periods are from the full moon to the eighth day 

 from the end of the month, from that to the fourth 

 day from the end, and from that to the new moon. 



The divisions of the day follow in general the 

 same principle : there is the sunrise, the mid-morning, 

 noon, mid-afternoon, and sunset; and the corres- 

 ponding divisions of the night have like effects in 

 the matter of winds storms and fair weather ; that 

 is to say, if there is to be a change, it will generally 



1 Plin. 18. 280. 2 cf. Arat. 73 f. 



395 



