Article of the month August
Decimal hours
In France, during the French Revolution, a time system using decimal hours was – unsuccessfully – introduced. A natural day was divided into ten hours.
One revolutionary hour thus lasted 2.4 ordinary hours.
Each “hour” was subdivided into 100 “minutes” of 100 “seconds” each.
See Article of the month of 2005, month 04
A new calendar system was also introduced, with twelve months of thirty days each.
Each month was subdivided into three periods of ten days each.
A remaining five or six days were added after the end of the last month to complete the year.
The new year began on the September equinox.
Fortunately, a few sundials remain which show this time system.
Here is a tile picture of such a sundial.
At the top is a double sundial, showing “normal” solar time as well as decimal hours.
Below are date curves for the new months and for a few special dates.
The new calendar and time system were abolished after only a few years.
