SA SU M TU WITHF SA SUM TUW THF [SA SUM (TU

SA SUM TUW THF SUM TUWTH F SA SU

APRIL.

JULY.

AUGUST.

MARCH.

COPYRIGHT, 1884, BY WILMOT H. THOMPSON, ORANGE, N. J.

NOV'R.

OCTOBER.

SEPT'R.

DEC'R.

quence D shows that this sequence is to be used for all oid style dates from 1600 to 1699, as the date of landing of Pilgrims, Dec. 11, O. S., 1620. At the right of sequence F, 16 shows that this is the sequence for all new style dates in the same period, as the landing of Pilgrims, Dec. 21, 1620. The 18 at right of sequence D indicates this as the one to use for the present century, 1800 to 1899.

Above or beneath those sequences are given, for each month, the odd years of the century, from 00 to 99, reading from left to right and so arranged that all the years of a century in which the first of the month falls on a certain day of the week are in the same colunin. Thus, take the table for January and the sequence for the present century, D, all the years in the first column, 4, 9, 15, 26, etc., are over Sunday in the sequence named; so the 1st of January in all these years is Sunday. In the second column are all the years in which the 1st falls on Monday, and so on. If we bear in mind that the 8th, 15th, 22d and 29th of any month will come on the same day of the week as the 1st, this arrangement gives at once the day of the week of five dates in any month, and from these the day of any other date in that menth can easily be found.

Now with a given date. to find the day of the week, as Aug. 23, 1841. In the table for August find the given year 41; take the sequence in line with the centurial year 18, D, and in this sequence above 41 we find Sunday. The August 1 in that year was Sunday, and the 8th, 15th and 22d must have fallen on Sunday also, and if the 22d was Sunday the 23d was Monday. What day of the week was Dec. 11, 0. S., 1620? Use sequence D for 1600s O. S. and in this above 20 in December find Friday. Then the 1st and the 8th came on Friday, and the 11th must have been MonCay.

Take the same date as given, new style, Dec. 21, 1620. Use sequence for the 1600s N. S. and above 20 find Tuesday, which was the 1st and the 22d, and the 21st was Monday. Then the Pilgrims landed on Monday.

If the last Thursday in November, 1885, be Thanksgiving Day, what will be the date? We find that in 1885 the 1st and therefore the 29th of November comes on Sunday; then the preceding Thursday, or Nov. 26th, is the last Thursday, or Thanksgiving Day.

This arrangement involves no comparison or distinction further than this: For the months of January and February of centesimal leap years only, as 1600, 2000, etc., by the Gregorian Calendar, the heavy-faced 00s in the first column are to be used, but for centesimal years not leap years the 00s in the second column are required. By the Julian Calendar every centesimal year was leap year; by the Gregorian Caler dar only every fourth centesimal year is a leap year. 1700 O. S. then should be regarded as a leap year, while 1700 N. S. is not.

on at

As to the intervals between the times when a given day of the month falls on a certain week-day, as Jan. 1st cn Saturday, this occurred in 1803-14-20-25-31, and so intervals of 11, 6, 5 and 6 years, which intervals are repeated and would continue without interruption but for the cmission of leap year in 1900, which will cause an irregularity of 12 years, either in one period, or in two intervals of 6 years each, or in one of 7 and another of 5 years, after which the regular intervals will be successively repeated again. But notice the difference in the grouping of the years under January and February, and that of the other ten months. Take the years in the column in which we find 3 under any other month, and the calendar for those months repeats as fol lows: 3, 8, 14, 25, 31, showing that the order for an entire year recurs less frequently, as in 3, 14, 25, 31. The order for any leap year is repeated at intervals of 28 years; thus the calendar for 1856 corresponds with that for 1884, and this order would obtain again in 1912 but for the omission of leap year in 1900, by which the interval is extended 12 years and the 29th of February will not fall on Friday again until 1924. The order for any year next succeeding a leap year will be repeated in 6 years, while the orders for the second and third years following a leap year will be epeated in 11 years. Then the calendar for '81 will be repeated in '87; the order tnat obtained in '82 will occur again in '93, and that for '83 corresponds with '94. What has been shown as to leap year dates, as Feb. 29th, recurring on the same day of the week, is of course true of Inauguration Day, March 4th, of every fourth year. This came on Sunday in 1821, 1849 and 1877, and if 1900 were a leap year it would occur again in 1905, but owing to that omission it will not recur until 1917. The irregular interval caused by the omission of leap year is sometimes 40 and sometimes 12 days. Under the Julian Calendar established 46 B. C. by Julius Caesar, the calendar for an entire century was repeated every 700 years, and therefore the sequence of days given here for 1700 O. S., G., answers also for the time 700 years earlier, i. e., the century 1000 to 1099; also for the years 300 to 399. In this way the sequences given may cover the time back to the beginning of the Christian Era. Under the Gregorian Calendar the orders are repeated every 400 years and only four of the sequences are required, viz., C, D, E and F; F serving alike for 1600 and 2000, E for 1700 and 2100, etc.

Pope Gregory XIII in 1582 undertook to reform the Julian Calendar. Το correct the errors that had accumulated and to guard against future inaccuracies, he suppressed ten days and provided for the omission of leap year every centesimai year, excepting every fourth centesimal year. Under the Gregorian Calendar 1700, 1800 and 1900 are not counted as leap years, but 1600 and 2000 are. This calendar was adopted by Germany in 1700 and by England not until 1752, by which time, as 1700 had passed as leap year, the difference amounted to 11 days, and Parliament rectified the error by suppressing 11 days in September of that year. The Julian Calendar stil: prevails in Russia, and as 1800 has passed with them as leap year, the difference between their reckoning and ours is 12 days, so that August 7 in Russia is the same as August 19

with us.