January 1st be represented by A, Sun. Feb. 1st (4 w. 3 d. from the preceding date) by D, Wed. Mar. 1st 4 w. 0 d. " " " by D, Wed. Apr. 1st 4 w. 3 d. " " " by G, Sat. May 1st 4 w. 2 d. " " " by B, Mon. June 1st 4 w. 3 d. " " " by E, Thur. July 1st 4 w. 2 d. " " " by G, Sat. Aug. 1st 4 w. 3 d. " " " by C, Tues. Sept. 1st 4 w. 3 d. " " " by F, Fri. Oct. 1st 4 w. 2 d. " " " by A, Sun. Nov. 1st 4 w. 3 d. " " " by D, Wed. Dec. 1st 4 w. 2 d. " " " by F, Fri. Now each of these letters placed opposite the months respectively represents the day of the week on which the month commences, and they are the first letters of each word in the preceding couplet. To find the day of the week on which a given day of any year will occur, we have the following RULE. Find the dominical letter for the year. Read from this to the letter which begins the given month, always reading from A toward G, calling the dominical letter Sunday, the next Monday, etc. This will show on what day of the week the month commenced; then reckoning the number of days from this will give the day required. EXAMPLES. History records the fall of Constantinople on May 29th, 1453. On what day of the week did it occur? We have then 1453 / 4 = 363 +; 1453 + 363 = 1816; 1816 / 7 = 259, remainder 3. Then 10 - 3 = 7; therefore, G being the seventh letter is dominical letter for 1453. Now reading from G to B, the letter for May, we have G Sunday, A Monday, and B Tuesday; hence May commenced on Tuesday and the 29th was Tuesday. The change from Old to New Style was made by Pope Gregory XIII, October 5th, 1582. On what day of the week did it occur? We have then 1582 / 4 = 395+; 1582 + 395 = 1977; 1977 / 7 = 282, remainder 3. Then 10 - 3 = 7; therefore, G being the seventh letter, is dominical letter for 1582. Now reading from G to A, the letter for October, we have G Sunday, A Monday, etc. Hence October commenced on Monday, and the 5th was Friday. On what day of the week did the 15th of the same month fall in 1582? We have then 1582 / 4 = 395+; 1582 + 395 = 1977; 1977 / 7 = 282, remainder 3. Then 6 - 3 = 3; therefore, C being the third letter, is the dominical letter for 1582. Now reading from C to A, the letter for October, we have C Sunday, D Monday, E Tuesday, etc. Hence October commenced on Friday, and the 15th was Friday. How is this, says one? You have just shown by computation that October, 1582, commenced on Monday, you now say that it occurred on Friday. You also stated that the 5th was Friday; you now say that the 15th was Friday. This is absurd; ten is not a multiple of seven. There is nothing absurd about it. The former computation was Old Style, the latter New Style, the Old being ten days behind the new.