134 THE GREEK ASTRONOMY. 



to the motions of the moon, and therefore must 

 be treated of hereafter. The Egyptians, on the 

 other hand, knowingly permitted their civil year 

 to wander, at least so far as their religious observ- 

 ances were concerned. "They do not wish," says 

 Geminus 15 , "the same sacrifices of the gods to be 

 made perpetually at the same time of the year, 

 but that they should go through all the seasons, 

 so that the same feast may happen in summer and 

 winter, in spring and autumn." The period in 

 which any festival would thus pass through all the 

 seasons of the year is 1461 years ; for 1460 years 

 of 365^ days are equal to 1461 years of 365 days. 

 This period of 1461 years is called the Sothic 

 period, from Sothis, the name of the dog-star, by 

 which their fixed year was determined ; and for the 

 same reason it is called the canicular period 16 . 



Other nations did not regulate their civil year 

 by intercalation at short intervals, but rectified it 

 by a reform when this became necessary. The 

 Persians are said to have added a month of 30 

 days every 120 years. The Roman calendar, at 

 first very rude in its structure, was reformed by 

 Numa, and was directed to be kept in order by the 

 perpetual interposition of the augurs. This, how- 

 ever, was, from various causes, not properly done ; 

 and the consequence was, that the reckoning fell 

 into utter disorder, in which state it was found by 



15 Uranol. p. 33. 



16 Censorinus de Die Natali, c. 18. 



