At 8:44 -0700 01/03/26, Dennis Brownridge wrote:
>Louis, I have seen a photo of one of those rare decimal watches of 1794-95.
>It is remarkably easy to read--much easier than our Babylonian analog clock,
>which requires several years for young children to master. The numbers are,
>in effect, decidays (large hand) and millidays (small hand), but I don't
>think they were actually called that. What were the official names of these
>units in the original legislation?
My understanding is that the day was divided in 10 (decimal) hours,
the hour in 100 (decimal)minutes and the minute in 100 (decimal)
seconds. The decimal second therefore was 0,864 of our seconds.
Gilbert Romme, one of the revolution leaders much interested in the
decimalization of time, had an image to make understand the value of
this second : it was equivalent to "the heart beats of a middle-size
man, in good health, marching at military pace". This demonstrates
how it was difficult even to a Revolutionist to get rid of
anthropometrical references. Curiously, in the ancient Egypt, the god
Thoth had also invented a decimal second (100 000 seconds in a mean
solar day). But it compared it to the heart beats of young Egyptian
ladies... What definition do you prefer ?
> And do you know why it failed so quickly?
Most people at the end of XVIII th century had no watches and indeed
did not need them : they satisfied themselves with the notions of
"morning", "midday", "evening". It was difficult to decimalize these
notions ! Therefore no interest in the population, contrary to the
other measures - where people were either for or against ! For those
who needed exact time, very few decimal clocks were actually
available, and thus they kept using traditional time : I saw a paper
dated early 1795 calling a meeting of the Public Education Committee
where the time was in old style hours !
Finally Prieur de la Côte d'Or, a Convention leader, admits in 1795
that "decimalization of day and hour would only bring confusion
without proportionate advantages" and the law of 18 germinal year III
"indefinitely defers use of decimal division of day and its parts".
Most ironically this law is the text by which the metric system
became a reality !
>Since watches were a new and costly item at that time, I have heard that
>there was opposition from both clockmakers and middle-class folks who feared
>that their expensive timepieces would be rendered obsolete. Is this true?
The Public Education Committee had launched an award for the making
of best decimal clocks and watches. Even decimal sun-dials were made
(one of them is to be seen at the Museum of Fine Arts in Boston). But
the prize was never awarded...
Louis
