Epacts

Epacts (literally epaktai hemerai, added days), in ecclesiastical reckoning of time, denote the excess of the solar month over the lunar month, or of the solar year over the lunar year. There are two systems by which the epacts are calculated. The later is the Gregorian Calendar of Epacts, which fixes them independently of sun or moon. The older or Italian system took the solar year as consisting of 365 days and the lunar of 354, the difference being 11 days. Every third year an intercalary lunar month of 30 days was put in, which reduced the difference to 3 days, which the addition of 11 days increased to 14. This process was continued for a cycle of 19 years, when 1 was added to the 20th epact, and the cycle was recommenced. Other adjustments are .necessary for leap years. The number of any particular year in the cycle is called the Golden Number; and, if 1 be added to the date of the year and the whole be divided by

19, the. resulting quotient gives the number of cycles that have elapsed since the beginning of the Christian era, and the remainder will be the golden number of the year, except when the year is the last of the cycle, in which case there is no remainder.