In a scalding-hot argument against the 12-month calendar, a September 1927 issue of The Outlook proclaimed: 'A month is a wholly irrational division of time. It has no relation to anything in astronomy, or human experience. It is an inaccurate and varying measure of time that is a constant annoyance in business and a misleading unit in science. It has no religious significance. A month is nothing but just a bad habit.'

The International Fixed Calendar is a solar calendar with 13 months of 28 days each. It is a perennial calendar as every date is fixed to the same weekday every year. Momentum behind the International Fixed Calendar, a 13-month calendar with 28 days in each month and a leftover day at the end of each year (it also followed the Gregorian rules with regards to Leap Years), was never stronger than in the late 1920s. Similar to Auguste Comte's positivist calendar (created in 1849), this particular 13-month invention came from the mind of Moses Cotsworth, a North Eastern Railway advisor bothered by inexplicably varying monthly earnings over the traditional 12-month period. In 1902, driven by a desire to simplify the ‘irrational calendar’ Moses B Cotsworth presented a solar calendar for calendar reform. His solar calendar had 13 months of 28 days each. Every date was fixed to the same weekday every year. Every week starts with a Sunday and ends with a Saturday. Cotsworth's plan quickly gained popularity among businessmen, especially in transportation and logistics. His biggest ally, however, was photography pioneer and Kodak founder, George Eastman. Impressed by the symmetry of this hyper-rational calendar, George Eastman adopted it for use in his Eastman Kodak Company 1928 to 1989 while the rest of the world followed the Gregorian calendar.

• Image 1: The 13-month calendar as used by Kodak in 1928 and 1989. Courtesy the George Eastman House
• Image 2, 3: A 1927 issue of "The Outlook" compares the Gregorian calendar to the International Fixed Calendar. Courtesy George Eastman House
• Image 3: Col. Henry Stimson (left) holds the report of the National Committee on Calendar Simplification while standing next to George Eastman on August 14, 1929. AP, George Eastman House
• Reference: Byrnes2014, Mark. “The Death and Life of the 13-Month Calendar.” Bloomberg.com. Bloomberg. Accessed December 6, 2020. https://www.bloomberg.com/news/articles/2014-12-11/the-death-and-life-of-the-13-month-calendar.

The French Republican Revolutionary Calendar established a new timekeeping system from 1793 until 1806. “This was introduced not to correct some astronomical discrepancy but to mark a break with the past. The Church, the guardian of the calendar with its feasts and fasts and saints’ days was one of the sources of power of the hated ancient order; it had to be done away with.”1 It employed ‘decimal time’ in order to be rational (in contrast to religious “irrationality”), and parallel the metric system. Using metric time was a proclamation that all Frenchmen became equal. A year had 12 months of 30 days each with 5 days at the year-end. Hence its power lay in its symbolic value rather than practical purpose. A leap year was to have an extra intercalary day. Months were standardized into three equal decades of 10 days each, each day was divided into 10 hours, hours into 100 minutes, and minutes into 100 seconds. This period also saw watchmakers build decimal clocks and watches. “Despite its revolutionary symbolism, the new calendar turned out to be unpopular and inconvenient. The French workman objected to working a 10-day week; most people objected to working on Sundays; the decimal hours caused intolerable confusion; business with the rest of Europe (still adhering to the Gregorian calendar) became difficult. As revolutionary fervour ebbed away, the provisions of the calendar were gradually repealed. In September 1805, Sunday was restored as the day of rest, and from 1 January 1806, the Gregorian calendar was reinstated.”

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• Image 1: Clock dial displaying both decimal (inside the circle) and duodecimal time (on the outer rim)
• Image 2: The French Republican Calendar
• Reference: Richards, E. G. Mapping Time: The Calendar and Its History. New York: Oxford University Press, 1999.

It was in May of 1929, at the fifth Congress of the Soviets of the Union, that it was proposed to alter the existing work-week in order to utilize expensive machinery in the factories more effectively and so raise productivity. The proposer, Larin, managed to interest Stalin in the project and on 26 August of the same year, the Council of People's Commissaries announced that the old work-week would be abolished and be replaced by a continuous production week known as 'nepreryvka'. A decree of 24 September modified the proposal by replacing the seven­day cycle with a five ­day one. The workers were issued with coloured slips of paper to tell them which day to take off: yellow, orange, red, purple, and green. They were to observe a day off on the day that fell on their colour.

While it did increase productivity as intended (80 per cent of the country was working at any given time), it disrupted social system by segregating families and friends, workers were demoralized, and machines could not be routinely maintained. However, there were two main disadvantages to nepreryvka. First, it had a profound, disruptive, and unwelcome effect on family and social life; members of the same family, friends, or marriage partners, who had been given different colours. Although the Soviet workers got more time off than then Western counterparts they were rarely able to spend time together.

• Image 1: Calendar for 1929–1930 showing rest days for each of the five worker groups, designated here by different colors. In this version of nepreryvka, the continuous workweek, workers had every fifth day off.
• Image 2: Left- The month of April from a 1931 worker’s pocket calendar. Here, the five different work groups are represented by five symbols—a sheaf of wheat, a red star, the hammer and sickle, a book, and a budenovka, or wool military cap. Courtesy Erast Butakov. Right- The month of July from the same 1931 worker’s pocket calendar. Here, the five different work groups are represented by five symbols—a sheaf of wheat, a red star, the hammer and sickle, a book, and a budenovka, or wool military cap. Courtesy Erast Butakov.
• Image 3: Calendar for 1929–1930 showing rest days for each of the five worker groups, designated here by different colors. In this version of nepreryvka, the continuous workweek, workers had every fifth day off.
• Courtesy of Tony Wood