LET. XIV. OF THE CALENDAR. 2Z7

■ -The new and full moons, which according toMeton, were imagined to happen at exactly thefame time as they had nineteen years before,were usually indicated in the following manner ;it was observed on what day of each calendarmonth the new moon fell, in each year of thisperiod, and against those days they placed thenumber answering to that year, reckoning fromone to nineteen, through all the years of thecycle. And those numbers, on account of theirgreat usefulness, were called Primes, or GoldenNumbers; but as Luilius' found them to beerroneous and inconvenient, he rejected themfrom his system, and made use of others, calledEpacts, in their stead.

The epact, is the difference between the solaryear and the lunar one ; or the moon’s age atthe end of the year. But, in order that thismay be better understood, 1 shall illustrate it byan example. Suppose, therefore, that at anyparticular time, the new moon was to happenon the first of January, the epact for that yearwould then be nothing. And as twelve luna-tions are completed in three hundred and sifty-four days, it is plain, that the epact, or moon'sage, at the beginning of the second year, wouldbe eleven ; at the beginning, of the third year,twenty-two; and at the beginning of the fourth,thirty-three. But as the time of one lunation isnevermore than twenty-nine days and a half,

the