ASHRAE Journal - June 2024 - 40

FEATURE
Celebrating Sadi
T
BY ANDY PEARSON, PH.D., C.ENG., FELLOW ASHRAE
he first explanation of the relationship
between heat and work, the science that we now
call " thermodynamics, " was published by the
French scientist Sadi Carnot exactly 200 years
ago. Carnot is world-famous but little of his
life story is known, and he is often incorrectly
characterized as a loner who developed
his theory in isolation from the scientific
community, not recognized in his lifetime.
Sadi was born in 1796 in a turbulent time in French
history, which created disruption for his whole life.
His father, Lazare Carnot, was a military engineer
who entered politics following the French Revolution,
becoming a delegate to the Legislature in 1791, then
Minister of War on the Committee of Public Safety in
1793 and then one of the five founding directors in the
" Directory, " the governing committee of the First French
Republic in 1795. One of Lazare's early moves during his
time as Director was to appoint 26-year-old Napoleon
Bonaparte as General in Chief of the Army of Italy,
marking the first step in Napoleon's rise to power.
The Directory inherited a difficult situation; the
" Reign of Terror " of the previous two years had
produced mass executions of royalists and priests
creating an atmosphere of suspicion. The country
was bankrupt and yet was at war with almost all its
neighbors, including Britain, Austria, Belgium, the
Netherlands, Spain, Prussia and Austria.
During this period, the revolutionary government
tried to introduce reforms including the Republican
calendar, which consisted of 12 months named after the
weather, each having three 10-day weeks followed by
five or six Complementary Days at the end of the year,
Andy Pearson, Ph.D., C.Eng., is group managing director at Star Refrigeration in Glasgow, UK.
40
ASHRAE JOURNAL ashrae.org J U N E 2024
MILITARY BEGINNINGS Sadi Carnot, pictured shortly before the battle
of Waterloo, and the Palais de Petit-Luxembourg.
known as the Sansculottides, literally the " days without
breeches, " meaning days for the working class to have a
break (Read about the French Revolutionary calendar at
https://tinyurl.com/JournalExtras). The revolutionary
government also introduced decimal time where each
day was divided into 10 hours of 100 minutes each and
each minute had 100 seconds. This innovation was
established on October 5, 1793, but as can be imagined
it did not go smoothly. Decimal time was suspended
on April 7, 1795, and the Republican calendar was
abandoned at the end of 1805.
Sadi Carnot was born into this chaos on 13 Prairial,
Year IV (June 1, 1796), in the luxury of the PetitLuxembourg
palace in Paris during his father's time
as Director of France. This palace was in keeping with
Lazare Carnot's status as a top politician in the Republic,
having only recently been vacated by Louis, Count of
Provence, who later was crowned King Louis XVIII.
Like many of France's politicians, Lazare's fortunes
swung wildly from extreme to extreme. In the coup
d'état of 18 Fructidor Year V (September 4, 1797) a rival
faction of the Directory seized power, martial law was
declared in Paris and General Carnot escaped into
exile in Geneva. His wife and son, aged 15 months,
TANGOPASO, VIA WIKIMEDIA COMMONS

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ASHRAE Journal - June 2024

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