GOLDEN NUMBER EPACT. 



each succeeding year of the cycle may be determined. The 

 number which expresses the age of the moon on the first day of 

 any year of the cycle is called the EPACT of that year. 



The series of EPACTS corresponding to the GOLDEN Numbers of 

 the years of a cycle are given in the following table : 



27. The age of the ecclesiastical moon on the first day of any 

 year being thus known by the EPACT, which, as well as the 

 GOLDEN NUMBEE, is given in the Almanack, the age of the moon 

 for every day of the same year can be ascertained, and by this 

 means the date of Easter, according to the conditions of the rule, 

 may be determined. 



28. To show the application of the Golden Numbers and Epacts, 

 and the departure of the ecclesiastical moon from the real moon, 

 let us take for example the year 1855. The Golden Number 

 being 13, the Epact, as appears by the above table, will be 12, 

 and consequently, on the 1st of January the ecclesiastical moon 

 will be in its 12th day. Its first day was, therefore, the 21st of 

 December. Now, by referring to the lunar tables given in the 

 almanacks, it will be found that the age of the real moon at the 

 midnight which commenced the 1st of January, was 12 days 2| 

 hours, and consequently the real moon was new on the evening of 

 the 19th of December, at three-quarters of an hour past 9 o'clock. 



It appears, therefore, that in this case there is a difference of 

 two days between the real and ecclesiastical moons. 



29. It is the ecclesiastical moon which alone figures in the 

 calendar, and by the phases of which the date of Easter is 

 governed : let us now see within what limits the variation of that 

 festival, and consequently of all the other moveable feasts which 

 depend on it, are confined. 



30. It appears by the rule, rightly interpreted, that Easter will 

 be the first Sunday after the 14th day of the ecclesiastical moon 

 which occurs next after the 20th of March. 



The earliest date of Easter compatible with these conditions 

 would be when the 14th day of the ecclesiastical moon would fall 

 on the 21st of March, and that the 21st of March itself should 

 fall on a Saturday. In that case the following day, that is, the 

 22nd of March, would be Easter Day. Earlier than this the 

 festival of Easter cannot fall, consistently with the rule laid down 

 by the Church. 



This contingency actually occurred in the year 1818. Its occur- 



15 



