Bissextile

Leap day is not the 29th day of February. It's the 24th. Rather, two days are counted as day 24. The Romans called the first day of the month Kalends, which is where we get the word "calendar." They counted down the days before Kalends, so the last day of February, the day before the Kalends of March, was numbered II. The 24th day was numbered VI. In leap years, there was an extra day VI in February, which was called bissextile. (Not bisexual!)

So those born on the last day of February in a leap year would cerebrate the last day every year, since it was counted as the 28th day, not 29. Likewise, those born on either the first or second 24 would celebrate on the 24th every year. No waiting four years!

MJD 60000.0

Watch the Modified Julian Date (MJD) roll over to a new myriaday, 60000.0. MJD is used to date star observations, and was the basis for stardates. One myriaday is 10,000 days, over 27 years. The next is in 2050.

Republican date & time

I updated the Calendars page to display the current Republican calendar date and decimal time, just as they were written in civil status registers during the Revolution, according to Paris Mean Time. 

I also added pages that calculate the first day of every year for the original equinox calendar and the revised calendar for 400 years and linked them from the calendars page. 

History of Time

I've been thinking about the history of time. 

Greek sundial

Sun Time

Ancient peoples used sundials to track the time of day. The Egyptians. divided the time between sunrise and sunset into 12 parts, or hours. The length of daily sunlight varied through the year, so the hours did, too, being longer in the summer and shorter in the winter. Nights were tracked by watching specific stars, and were also divided into 12 hours, making 24 total. Sometimes, dripping water was used to track time at night. 

Decimal time abandoned

Why was decimal time abandoned during the Revolution? C.A. Prieur (of the Côte-d'Or), read at the National Convention on Ventôse 11, year III (March 1, 1795):

Six years of decimal time

 

Although decimal time was required for public records for only six months from September 22, 1794, to April 7, 1795, some cities used it for as long as six years, until after Napoleon's coupe of 18 Brumaire. 

Midnight to one hour

This birth certificate from the town of Russey in Doubs says:

Aujourd'hui quinze Nivose troisième année de la République une et indivisible à cinq heures décimales…le Jour d’hier quatorze du courant à quatre vingt trois minutes trente trois secondes du matin…

History of the week

The 7-day week began in the Middle East. Babylonia kept track of the phases of the moon. Lunar calendar months begin with the first crescent. From there to the first half moon was 7 days, then 7 more days until the full moon, another 7 until the last half moon, then 7 more until the last crescent, followed by 1 or 2 intercalary days of no moon, which might have been added to the last week. This was apparently adopted by the Jews while in exile, as the Hebrew word for the 7th day, Sabbath, comes from Sabattu, meaning full moon, or literally, "middle rest" day in Babylonian.

The average month is 29.5 days, with no moon visible the last day or two, called "intercalary," so two consecutive months would look like this:

Princess Elisa’s Marriage Certificate

This is the marriage certificate for Napoleon’s sister, Princess Elisa, married in Marseille  

𝐿'𝒶𝓃 𝒞𝒾𝓃𝓆 𝒟𝑒 𝓁𝒶 𝑅𝑒́𝓅𝓊𝒷𝓁𝒾𝓆𝓊𝑒 𝒻𝓇𝒶𝓃𝒸𝒶𝒾𝓈𝑒 𝓊𝓃𝑒 𝑒𝓉 𝒾𝓃𝒹𝒾𝓋𝒾𝓈𝒾𝒷𝓁𝑒 𝐿𝑒 𝒟𝑜𝓊𝓏𝑒 𝒻𝓁𝑜𝓇𝑒𝒶𝓁 𝒶̀ 𝒮𝑒𝓅𝓉 𝒽𝑒𝓊𝓇𝑒𝓈 𝒞𝒾𝓃𝓆 𝒟𝑒́𝒸𝒾𝓂𝑒𝓈

The year five of the French Republic one and indivisible twelve Floreal at seven hours five décimes (7.5 h)

That’s May 1, 1797, at 6:00 pm. 

 

Hello

I see that I haven't posted here in 7 years. I also haven't renewed my domain names, but Google still keeps zombie blogs, so the BlogSpot address is working. There seems to be little interest in decimal time anymore, not that there was ever a lot. I think that may partially because one can get all the info from Wikipedia. Even there, I seem to be the only one updating the article.

Another reason for neglect here is most discussion has moved away from blogs to social media, like Twitter and Facebook. I noticed recently that somebody started a Decimal Time Facebook group, but nobody is posting there, either.

Another we didn't have 20 years ago was all the genealogical records online. I can now read all the records of births, deaths, and marriages for all of France. Whereas before there where very few examples of decimal time in use during the Revolution, now there are thousands. So, I need some place to write down my observations, even if nobody read them.

Sextidi 16 Pluviôse de la République française une et indivisible à 8 heures 87 minutes décimales