If you take a close look at the watch shown above, you will begin to notice some oddities. This is a precision watch with decimal hours and seconds by Robert Robin from 1793. In this system there are 100 seconds in a minute and 100 minutes in an hour. Decimal time is the representation of the time of day using units which are decimally related. This term is often used to refer specifically to French Revolutionary Time.
10 metric hours in a day
In 1788, Claude Boniface Collignon proposed dividing the day into 10 hours or 1000 minutes, each new hour into 100 minutes, each new minute into 1000 seconds, and each new second into 1000 tierces. The distance the sun travels in one new tierce at the equator, which is one-billionth of the circumference of the earth, would be a new unit of length, provisionally called a half-handbreadth, equal to four modern centimeters. Further, the new tierce would be divided into 1000 quatierces, which he called “microscopic points of time”. He also suggested a week of 10 days and dividing the year into 10 “solar months”. The final French Republican Calendar was introduced in 1793 with 30 days in a month and 12 months/ 360 days in a year, using a decimal timescale, adding 5 days of festivities at the end of the year. The Republican Calendar was not a success and lasted only from 1793 until 1805.