| For, says he, because of the double epact that occurs on the 4th and 5th of April that lunation has only 29 days. |
| On account of the solar equation S, the epact J must be diminished by unity every centesimal year, excepting always the fourth. |
| The epact is the number of days which must be added to a lunar year to complete a solar year. |
| Having determined the epact of the year, it only remains to find Easter Sunday from the conditions already laid down. |
| The epact thus continues to vary until at the end of nineteen years the new moons return as at first. |
| Thus we have the epact, or age of the Calendar moon at the beginning of the year. |
