Armelin's calendar
Open-knowledge reference entry
Armelin's calendar was developed around 1887 by French astronomer Gaston Armelin, who developed a twelve-month calendar in which the year of 364 days was divided into four equal quarters of 91 days.
Armelin's calendar proposal was discussed chiefly under the auspices of the Société astronomique de France in 1887 and recently in the French Academy of Sciences.
Structure
The year is divided into four quarters of three months each, and the arrangements for the first quarter repeat in each of the other quarters. The first and second month of each quarter have thirty days, and the third month 31 days. This accounts for 91 days in each quarter, or 364 days in all.
The remaining day in ordinary years is "New Year's Day". It is given no other descriptive title. It does not belong to any week or any month. It begins the year. January 1 is the day following New Year's Day.
The public source identifies “Armelin's calendar” as open-knowledge reference entry. This brief keeps that definition visible, then builds a research path around Armelin's, calendar and Open-knowledge.
Why this record matters
A short description can identify a subject without explaining its stakes. For “Armelin's calendar”, the useful work is to connect “open-knowledge reference entry” to the records capable of establishing context and consequence.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated May 20, 2025. The linked authority identifier is Q4209275. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1887.
The absence of detail may reflect summary conventions rather than a lack of surviving documentation. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Armelin's calendar”, its source revision and the description used here.
- Expand the search: follow Armelin's calendar primary sources, Armelin's calendar archive and Armelin's research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Armelin's calendar”?
- Which cited source is closest to the event, object or claim?
- Which institution is responsible for the underlying evidence?
Search terms from this dossier
This entry incorporates text from “Armelin's calendar” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.