International Fixed Calendar
Encyclopedia
The International Fixed calendar
(also known as the International Perpetual calendar, the Cotsworth plan, the Eastman plan, the 13 Month calendar or the Equal Month calendar) is a solar calendar
proposal for calendar reform
designed by Moses B. Cotsworth
who presented it in 1923 providing for a year of 13 months of 28 days each, with one day at the end of each year belonging to no month or week. Though it was never officially adopted in any country, it was the official calendar of the Eastman Kodak Company from 1928 to 1989.
year.
The months have the same names as those of the Gregorian calendar
, except that a month called Sol is inserted between June and July.
There is one leap year
, with 366 days, every four years in order to compensate, as in the Gregorian calendar, the ~365.25 days per year. On that year, a leap day is inserted after June and before Sol.
Days that do not belong to a month are deemed to be outside the week and always occur between a day deemed Saturday and a day deemed to be Sunday.
The first day of each year, January 1, is deemed a Sunday and every subsequent day that belongs to a month is deemed to be in the conventional 7-day week.
Because each month consists of exactly four weeks, the first day of each month and every seventh day after that for the rest of the month is deemed to be a Sunday, the second day of each month and every seventh day after that for the rest of the month is deemed to be a Monday, and so on. Therefore, each month begins on a Sunday and ends on a Saturday, just like each conventional week.
This causes all months to look like this:
The 13 months and extra days occur on the following Gregorian dates:
* These dates are a day earlier in a leap year.
was founded in 1923 by Moses B. Cotsworth
, with offices in London and later in Rochester, New York
. It ceased activities in the 1930s.
George Eastman
of the Eastman Kodak Company was a fervent supporter of the IFC, and instituted its use at Kodak in 1928, where it remained in use until 1989.
In recent years, there have been attempts to revive the plan.
The International Perpetual calendar is based on the Positivist Calendar
published in 1849 by French philosopher Auguste Comte
(1798–1857). Comte based his calendar on Polynesian calendars. The main difference between the International Perpetual calendar and the Positivist calendar is the names Comte gave to months and days. The months in the Positivist calendar were, in order: Moses
, Homer
, Aristotle
, Archimedes
, Caesar
, St. Paul
, Charlemagne
, Dante
, Gutenberg, Shakespeare, Descartes, Frederic
and Bichat. Every day of the year was likewise named. Positivist weeks, and Positivist months, begin with Monday instead of Sunday. Whereas the Positivist and Sol calendars place the leap day at the end of the leap year, the International Fixed Calendar and the World Calendar both place it after June.
When compared to other proposals, this calendar keeps the same days per year, and the same days per week, which are two advantages that ease possible change.
In Gregorian calendar, the New Year's Day
is a world holiday. On this proposal, that day is a Sunday by definition, which obsoletes the world holiday, substituting it by a weekend day.
On this proposal, the number of national holidays that do not fall on weekends are no longer year dependent. This no longer causes certain years to have more workdays than others.
, and this date occurs thirteen times every year.
Thirteen, being prime, is not evenly divisible, putting all activities currently done on a quarterly basis out of alignment with the months.
Several religious groups oppose any interruption of the seven-weekday sequence.
Calendar
A calendar is a system of organizing days for social, religious, commercial, or administrative purposes. This is done by giving names to periods of time, typically days, weeks, months, and years. The name given to each day is known as a date. Periods in a calendar are usually, though not...
(also known as the International Perpetual calendar, the Cotsworth plan, the Eastman plan, the 13 Month calendar or the Equal Month calendar) is a solar calendar
Solar calendar
A solar calendar is a calendar whose dates indicate the position of the earth on its revolution around the sun .-Tropical solar calendars:...
proposal for calendar reform
Calendar reform
A calendar reform is any significant revision of a calendar system. The term sometimes is used instead for a proposal to switch to a different calendar.Most calendars have several rules which could be altered by reform:...
designed by Moses B. Cotsworth
Moses B. Cotsworth
Moses Bruine Cotsworth was a calendar reformer.He started his career in a variety of companies where his analytical skills were valuable. Based on his work at the North Eastern Railway Company, he published a book on railway rates...
who presented it in 1923 providing for a year of 13 months of 28 days each, with one day at the end of each year belonging to no month or week. Though it was never officially adopted in any country, it was the official calendar of the Eastman Kodak Company from 1928 to 1989.
Rules
The calendar year has 13 months each with 28 days (divided in exactly 4 weeks) plus an extra day at the end of the year not belonging to any month (and so 365 days). Each year coincides with the corresponding GregorianGregorian calendar
The Gregorian calendar, also known as the Western calendar, or Christian calendar, is the internationally accepted civil calendar. It was introduced by Pope Gregory XIII, after whom the calendar was named, by a decree signed on 24 February 1582, a papal bull known by its opening words Inter...
year.
The months have the same names as those of the Gregorian calendar
Gregorian calendar
The Gregorian calendar, also known as the Western calendar, or Christian calendar, is the internationally accepted civil calendar. It was introduced by Pope Gregory XIII, after whom the calendar was named, by a decree signed on 24 February 1582, a papal bull known by its opening words Inter...
, except that a month called Sol is inserted between June and July.
There is one leap year
Leap year
A leap year is a year containing one extra day in order to keep the calendar year synchronized with the astronomical or seasonal year...
, with 366 days, every four years in order to compensate, as in the Gregorian calendar, the ~365.25 days per year. On that year, a leap day is inserted after June and before Sol.
Days that do not belong to a month are deemed to be outside the week and always occur between a day deemed Saturday and a day deemed to be Sunday.
The first day of each year, January 1, is deemed a Sunday and every subsequent day that belongs to a month is deemed to be in the conventional 7-day week.
Because each month consists of exactly four weeks, the first day of each month and every seventh day after that for the rest of the month is deemed to be a Sunday, the second day of each month and every seventh day after that for the rest of the month is deemed to be a Monday, and so on. Therefore, each month begins on a Sunday and ends on a Saturday, just like each conventional week.
This causes all months to look like this:
| Sun | Mon | Tue | Wed | Thu | Fri | Sat |
|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| 8 | 9 | 10 | 11 | 12 | 13 | 14 |
| 15 | 16 | 17 | 18 | 19 | 20 | 21 |
| 22 | 23 | 24 | 25 | 26 | 27 | 28 |
The 13 months and extra days occur on the following Gregorian dates:
| Month | Starts | Ends |
|---|---|---|
| January | January 1 | January 28 |
| February | January 29 | February 25 |
| March | February 26 | March 25* |
| April | March 26* | April 22* |
| May | April 23* | May 20* |
| June | May 21* | June 17* |
| Leap Day | June 17 | |
| Sol | June 18 | July 15 |
| July | July 16 | August 12 |
| August | August 13 | September 9 |
| September | September 10 | October 7 |
| October | October 8 | November 4 |
| November | November 5 | December 2 |
| December | December 3 | December 30 |
| Year Day | December 31 | |
History
The International Fixed Calendar LeagueInternational Fixed Calendar League
The International Fixed Calendar League was an organization that campaigned to establish the International Fixed Calendar, a calendar of 13 months of 28 days each with one extra day at the end of each year called the "Year-day"....
was founded in 1923 by Moses B. Cotsworth
Moses B. Cotsworth
Moses Bruine Cotsworth was a calendar reformer.He started his career in a variety of companies where his analytical skills were valuable. Based on his work at the North Eastern Railway Company, he published a book on railway rates...
, with offices in London and later in Rochester, New York
Rochester, New York
Rochester is a city in Monroe County, New York, south of Lake Ontario in the United States. Known as The World's Image Centre, it was also once known as The Flour City, and more recently as The Flower City...
. It ceased activities in the 1930s.
George Eastman
George Eastman
George Eastman was an American innovator and entrepreneur who founded the Eastman Kodak Company and invented roll film, helping to bring photography to the mainstream...
of the Eastman Kodak Company was a fervent supporter of the IFC, and instituted its use at Kodak in 1928, where it remained in use until 1989.
In recent years, there have been attempts to revive the plan.
The International Perpetual calendar is based on the Positivist Calendar
Positivist calendar
The positivist calendar was a calendar reform proposal by Auguste Comte in 1849. After revising the earlier work of Marco Mastrofini, Comte's proposed calendar was a solar calendar which had 13 months of 28 days, and an additional festival day commemorating the dead, totalling 365 days.This extra...
published in 1849 by French philosopher Auguste Comte
Auguste Comte
Isidore Auguste Marie François Xavier Comte , better known as Auguste Comte , was a French philosopher, a founder of the discipline of sociology and of the doctrine of positivism...
(1798–1857). Comte based his calendar on Polynesian calendars. The main difference between the International Perpetual calendar and the Positivist calendar is the names Comte gave to months and days. The months in the Positivist calendar were, in order: Moses
Moses
Moses was, according to the Hebrew Bible and Qur'an, a religious leader, lawgiver and prophet, to whom the authorship of the Torah is traditionally attributed...
, Homer
Homer
In the Western classical tradition Homer , is the author of the Iliad and the Odyssey, and is revered as the greatest ancient Greek epic poet. These epics lie at the beginning of the Western canon of literature, and have had an enormous influence on the history of literature.When he lived is...
, Aristotle
Aristotle
Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...
, Archimedes
Archimedes
Archimedes of Syracuse was a Greek mathematician, physicist, engineer, inventor, and astronomer. Although few details of his life are known, he is regarded as one of the leading scientists in classical antiquity. Among his advances in physics are the foundations of hydrostatics, statics and an...
, Caesar
Julius Caesar
Gaius Julius Caesar was a Roman general and statesman and a distinguished writer of Latin prose. He played a critical role in the gradual transformation of the Roman Republic into the Roman Empire....
, St. Paul
Paul of Tarsus
Paul the Apostle , also known as Saul of Tarsus, is described in the Christian New Testament as one of the most influential early Christian missionaries, with the writings ascribed to him by the church forming a considerable portion of the New Testament...
, Charlemagne
Charlemagne
Charlemagne was King of the Franks from 768 and Emperor of the Romans from 800 to his death in 814. He expanded the Frankish kingdom into an empire that incorporated much of Western and Central Europe. During his reign, he conquered Italy and was crowned by Pope Leo III on 25 December 800...
, Dante
DANTE
Delivery of Advanced Network Technology to Europe is a not-for-profit organisation that plans, builds and operates the international networks that interconnect the various national research and education networks in Europe and surrounding regions...
, Gutenberg, Shakespeare, Descartes, Frederic
Frederick II of Prussia
Frederick II was a King in Prussia and a King of Prussia from the Hohenzollern dynasty. In his role as a prince-elector of the Holy Roman Empire, he was also Elector of Brandenburg. He was in personal union the sovereign prince of the Principality of Neuchâtel...
and Bichat. Every day of the year was likewise named. Positivist weeks, and Positivist months, begin with Monday instead of Sunday. Whereas the Positivist and Sol calendars place the leap day at the end of the leap year, the International Fixed Calendar and the World Calendar both place it after June.
Advantages
Several advantages do exist on this calendar, mainly related to its organization. When compared to the Gregorian, it is clear that this calendar is much simpler and pratical:- every year has exactly 52 weeks divided in 13 months;
- each month has exactly 28 days divided in 4 weeks;
- every month/year's day has the same week day (i.e. n'th month/year day is always the m'th week's day, where m is the reminder of n/7).
When compared to other proposals, this calendar keeps the same days per year, and the same days per week, which are two advantages that ease possible change.
In Gregorian calendar, the New Year's Day
New Year's Day
New Year's Day is observed on January 1, the first day of the year on the modern Gregorian calendar as well as the Julian calendar used in ancient Rome...
is a world holiday. On this proposal, that day is a Sunday by definition, which obsoletes the world holiday, substituting it by a weekend day.
On this proposal, the number of national holidays that do not fall on weekends are no longer year dependent. This no longer causes certain years to have more workdays than others.
Disadvantages
For the superstitious, a disadvantage to this format is that every month includes a Friday the 13thFriday the 13th
Friday the 13th occurs when the thirteenth day of a month falls on a Friday, which superstition holds to be a day of bad luck. In the Gregorian calendar, this day occurs at least once, but at most three times a year...
, and this date occurs thirteen times every year.
Thirteen, being prime, is not evenly divisible, putting all activities currently done on a quarterly basis out of alignment with the months.
Several religious groups oppose any interruption of the seven-weekday sequence.
External links
- Article on the International Fixed Calendar League at the International Institute of Social History Archives.
- Article about the Cotsworth Calendar of George Eastman.