DAY OF THE WEEK. To find the day of the week for any date, past or future, there are several methods, but the simplest and most easily understood is as follows: First, there is a "constant" for the style—for new style it is 6; for old style, 4. (In English chronology, new style begins 1759, Sept. 15.) Then there is a "constant" for each month: in new style, Jan., 1; Feb., 4; Mar., 4; April, 0; May, 2; June, 5; July, 0; Aug., 3; Sept., 6; Oct., 1; Nov., 4; Dec., 6; (on leap years the constants for Jan. and Feb. are one less, that is, for Jan., 0; for Feb., 3). Now (for new style), multiply the number representing the century by 5, and add one fourth to the product (omittino. frac tions). For instance: in 18S0 the century number is 18, which multiplied by 5 makes 90, and one fourth of 18 (omitting fractions) is 4; hence the product is 94. Next add the number of the odd years (besides the century number), and add one fourth (omitting fractions) to their total. Next add the day of the month. Then add all these figures together, and finally, divide the sum by 7: the remainder will show the day of the week; remainder of 1 showing the first day of the week, or Sunday; remainder of 2 showing the second day of the week, or Monday, etc.; no remainder showing the
7th day of the week, or Saturday. Illustration; What is the day of the week for Jan. 1, 1881? Constant for new style ... .. . 6 r Odd years 81 Constant for the month (Jan.) 1 ' Add one fourth of 81 20 Century (18) multiplied by 5.... 90 1 Day of the month 1 Add one fourth of 18 4 I Total 203 Divide 203 by 7, and there is no remainder; so the year 1881 must begin on the 7th day of the Week, or Saturday.
For old style the constant is 4, and the number of the century is multiplied by 6. without addition of the one fourth. The constants for months are the same as in new style, and one fourth (omitting fractions) is added to the odd years. Example for old style: On what day of the week did Columbus land on his voyage of discovery (Oct. 12, 1492)? Constant for old style ..... 4 I Odd years (92) one fourth added.... ..115 Constant for Oct 1 Day of the month 12 Century (14) multiplied by 6 .. 84 Total ... .. . 216 Divide by 7, and the remainder is 6—the 6th day of the week, or Friday. For leap Years, care must be taken in both old and new style to reduce the constants for Jan. and Pei). by one, for each of those two months.