France's recent time change echoes a radical 1793 experiment that redefined the day into 10 hours, 100 minutes, and 100 seconds as part of the Republican calendar.
France delays clocks again
In the night of October 24 to 25, 2026, France delayed its clocks by one hour, reigniting the annual debate over daylight saving time. This change is part of the country’s regular practice of adjusting clocks twice a year to align with seasonal changes in daylight.Historical time experiment
This event echoes a more radical historical experiment in timekeeping that occurred in 1793, during the French Revolution. The National Convention introduced a new way of dividing the day, as part of the Republican calendar, which aimed to standardize measurements across France.Decimal time system
The National Convention decreed a day of 10 hours, each divided into 100 minutes, with each minute further divided into 100 seconds. This system, introduced through a decree in October 1793, aimed to simplify timekeeping and align it with the metric system, which was also being established at the time.Time conversions and effects
A decimal hour was equivalent to 2 hours and 24 minutes in the traditional system, and the entire day consisted of 100,000 decimal seconds, compared to 86,400 seconds in the traditional system. Noon in this system fell at 5 decimal hours, and an appointment at 3 decimal hours corresponded to 7:12 in the morning.Clockmakers adapt
Clockmakers responded by producing double-faced watches that could read both the decimal and traditional time systems. This allowed people to keep track of time under both systems, reflecting the transitional period during which the decimal time was in use.Decimal time ends
The obligation of decimal time was suspended on April 7, 1795, after 197 days. Although the metric system succeeded in standardizing measurements, the decimal time system was ultimately abandoned, though some communities continued to use it for official purposes for several years afterward.Legacy in Paris
In Toulouse, the Capitole kept a decimal clock, and at the Tuileries, two of the four clock faces displayed decimal time until at least 1801, six years after the end of the obligation. This shows that the decimal time system had a lasting presence in some parts of France even after its official discontinuation.Comparison with modern time changes
The contrast with the current time change is striking, as advancing or setting back the hands by 60 minutes twice a year keeps the same second, minute, and hour, unlike the radical redivision of time units attempted by the National Convention in 1793.Uncertain end to decimal time
One uncertainty remains: for the Tuileries, the sources mention 1801 "at least," which leaves the date open as to when the two decimal clock faces actually stopped marking time for Parisians. This uncertainty highlights the complexity of tracking the transition from decimal to traditional time.
