Determination of the day of the week the day of the week without any calculations. Examples: December is in row F and 26 is in column E, so the letter for the date is C located in row F and column E. 93 (year mod 100) is in row D (year row) and the letter C in the year row is located in column G. 18 ([year/100] in the Gregorian century column) is in row C (century row) and the letter in the century row and column G is B, so the day of the week is Tuesday. October 13 is a F day. The letter F
Three-Day Week Three-Day Week The Three-Day Week was one of several measures introduced in the United Kingdom by the Conservative Government to conserve electricity, the generation of which was severely restricted owing to industrial action by coal miners. The effect was that from 1 January until 7 March 1974 (also the same month the 1973-74 oil crisis ended) commercial users of electricity were limited to three specified consecutive days' consumption each week and prohibited from working longer hours on those days. Services deemed essential (e.g. hospitals, supermarkets and newspaper prints) were exempt. Television companies were required to cease broadcasting at 10:30 p.m.