EXAMPLE. Let it be required to find the dominical letter for the year 150 before Christ. Subtract one from the given year, which leaves 149, and it will be found from entering 'fable IV. with the 100 years at the head, and the 49 at the side, that A is the dominical let ter required.
The solar cycle is a period of 28 years, at the end of which the days of the week correspond to the same clays of the month.
The first seven letters of the alphabet, A, B, C, D, E, F, G, have been employed by chronologers to mark the several days of the week, the first letter standing for the first of January, and so on ; and since one of these letters must necessarily stand opposite to Sunday, it is called the donzinical letter, or Sunday letter, and is prin ted in a capital form, the other six letters, which de signate the other six days of the week, being printed in small characters. Then, since a Julian year of 365 days contains 52 weeks and one clay, it is obvious that the year must begin and end on the same clay of the week, and consequently the next year must commence on the day following. Had there been only 52 weeks in the
common year, without any clays remaining, the year would have constantly begun on the same day of the week. When January, therefore, begins on Sunday, the dominical letter for that year is A, and since the next year must begin on Monday, Sunday will be the 7th day, to which the letter G is annexed, which will therefore he the dominical letter for that year. The third year will begin on Tuesday, and as Sunday falls on the sixth day, F will be the dominical letter. Hence it follows that the dominical letters will succeed each other in a retrograde order, viz. G, F, E, 1), C, B, A, and if there was no leap year, the same days of the week would, in the course of seven years, return to the same days of