BOOK XMII. Lvi. 206-Lvii. 209 



even experts have bcen conscious of, in order that 

 subscquentlv our minds may more happily pass on 

 from the studv of the heavens and discern the actual 

 events of the past whose future occurrence cannot 

 be known in advance. 



LVII. First of all it is almost impossible to explain rrindples o/ 

 the system of the actual days of the year and that "^ ''"'"^v- 

 of the movement of the sun, because to the 365 

 days an intercalary year adds a quarter of a day 

 and of a night, and consequently definite periods of 

 the stars cannot be stated. In addition to this 

 there is the admitted obscurity of the facts, as 

 sometimes the specification of the seasons runs in 

 advance, and by a considerable number of days 

 (the Greck term" for this is TrpoxtLixdt^f.a'), whereas at 

 other times it comes behind (in Greek cVixei/Aa^eiv), 

 and in general the influence of the heavens falls 

 down to the earth in one place more quickly and 

 in another place moro slowly ; this is the cause of 

 the remark we commonly hear on the return of 

 fine weather, that a constellation has been com- 

 pleted. Moreover although all these things depend 

 on stars that are stationary and fixed in the sky, 

 there intervene movements of stars and hailstorms 

 and rain, these also having no inconsiderable effect, 

 as we have shown, and they disturb the regularity § 152. 

 of the expectation that has been conceived. And 

 we must not think that this occurs only to ourselves — 

 it also deceives the rest of the animals, which have 

 greater sagacity about this matter, inasmuch as it is 

 a thing on which their life depends ; and the birds 

 of summer are killed by exceptionally late or ex- 

 ceptionally early frosts, and those of winter by un- 

 timely spells of heat. This is why Virgil teaches the Georg.i.zzi. 



321 



