EPACT

In chronology, and in the tables for the calculation of Easter, a number indicating the exce of the solar above the lunar year. The solar year consisting, in round numbers, of 365 days, and the lunar of twelve months, of twenty-nine and a half days each, or 354 days, there will be an overplus in the solar year of eleven days, and this constitutes the Epact . In other words, the epact of any year expre es the number of days from the last new moon of the old year (which was the beginning of the present lunar year) to the first of January. In the first year, therefore, it will be 0; in the second 11 days; in the third twice 11 or 22; and in the fourth it would be 11 days more, or 33; but 30 days being a synodical month, will in that year be intercalated, making thirteen synodical months, and the remaining three is then the epact. In the following year, 11 will again be added, making fourteen for the epact, and so on to the end of the cycle, adding 11 to the epact of the last year, and always rejecting thirty, by counting it as an additional month. The epact is inserted in the table of moveable feasts in the Prayer Book.