Determination of the day of the week his adjustments for centuries are to be determined using formulas similar to those for the centuries table. Although explicit in asserting that his method also works for Old Style dates, his example reproduced below to determine that "1676, February 23" is a Wednesday only works on a Julian calendar which starts the year on January 1, instead of March 25 as on the "Old Style" Julian calendar. Algorithm: Take the given date in 4 portions, viz. the number of centuries, the number of years over, the month, the day of the month. Compute the following 4 items, adding each, when
Eight-day week a day. Further, they also counted the ending night period, giving rise to periods of time with more nights than days. In Irish, the term "nómad" is used to signify a small number of days and is exactly the length of the nine night week as in "co cend nomaide" - a period of time with nine nights bracketing eight days. The nine nights divided nicely into a sidereal month of 27 nights. In Welsh a similar word "wythnos" meaning "a week" literally means "an eight-night" since it started and ended with a period of night bracketing seven days. Similarly