Nicolas Léonard Sadi Carnot Biography

(French Mechanical Engineer Who is Described as the Father of Thermodynamics)

Birthday: June 1, 1796 (Gemini)

Born In: Paris, France

Nicolas Léonard Sadi Carnot was a French mechanical engineer also known as the ‘father of thermodynamics.’ Born into an esteemed French political family, Sadi was initially tutored by his father. He eventually attended college to study military engineering. Due to his father’s exile, he was not treated well in the military. Hence, he took his retirement and pursued his other interest, which was thermodynamics. His research work was mainly concentrated on the workings of a steam engine, which further gave birth to the field of thermodynamics. He wrote only one book in his lifetime, titled Reflections on the Motive Power of Fire. In the book, he laid down his theory of the maximum efficiency of steam engines. It was of no great use at that time but over the decades, this theory of thermodynamics became the base for the development of automobiles and jets. The book was not received as nicely initially and only became popular after his demise in 1832. Many engineers used his work as the base and revolutionized the European industrial landscape. Sadi passed away from cholera at the young age of 36.

Quick Facts

French Celebrities Born In June

Also Known As: Nicolas Léonard Sadi Carnot

Died At Age: 36


father: Lazare Carnot

siblings: Hippolyte Carnot

Born Country: France

Engineers Physicists

Died on: August 24, 1832

place of death: Paris, France

Notable Alumni: École Royale Du Génie, Collège De France

Cause of Death: Cholera

City: Paris

More Facts

education: École Polytechnique, University Of Paris, Collège De France, École Royale Du Génie

Childhood & Early Life

Nicolas Léonard Sadi Carnot was born on June 1, 1796, in Paris, into a highly esteemed family. His family was deeply involved in the world of politics with his father Lazare Carnot being a revolutionary figure in French politics. Sadi was named after a Persian poet named Sadi of Shiraz.

His father was Napolean’s Minister of War in 1799. Nicolas was born amidst political and social unrest in France and due to his father’s position in politics, his early years were highly unstable and unpredictable. His father was also a well-learned man well equipped in different subjects such as science and mathematics. He retired from politics in 1807 and focused on providing quality education to both his sons.

Sadi took early classes from his father and became well versed in science and mathematics by the time he was 15 years old. For his further education, his father attempted to get him enrolled at the Lycée Charlemagne in Paris. It was the first step to getting his son enrolled at the École Polytechnique, which was one of the greatest technological institutes in entire France. Sadi was 16 years old at that time and got enrolled at the Polytechnique meeting the minimum age requirement.

At the institute, Sadi was taught by some of the greatest minds in France such as  Poisson, Ampère and Arago. Following his graduation from the Polytechnique, he enrolled at the École du Génie at Metz to pursue military engineering.

His father was made the minister of interior under Napolean’s government and this made it a little difficult for Sadi at the institute. However, following Napolean’s final loss in the Battle of Waterloo in 1815, his father was exiled to Germany and never returned.

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Meanwhile, Sadi graduated from the institute and embarked on a military engineering career. It was assumed that with his father in exile, it was not good for Sadi to maintain a respectable position in the new government. Sadi being the son of an exiled minister in Napolean’s government was treated harshly in the military.

He was mostly doing the work of inspecting fortifications, writing reports and drawing up plans. He was also made to move from place to place for his work. His recommendations were also almost negligible. Tired of this treatment, Sadi made up his mind to try something else. One hope came in form of the newly formed General Staff Corps in Paris, which he joined in 1819.

He eventually moved to Paris and began to live in his father’s old Paris apartment. Sadi was losing interest in his work and he retired with half pay. However, by this time he had become deeply interested in science and technological innovations. Although he was retired, he was always on the call for Army duty.

To further broaden the landscape of his knowledge he studied various scientific subjects at Sorbonne and the Collège de France. Around 1820 was the time when he became serious about science and industrial problems. Initially, his main area of curiosity was the study of industrial gases.

Steam engines had been built a few years prior and Sadi became hugely interested in the subject. He thus began his studies on thermodynamics which he thought would be the next big step for mankind. British steam engines were popular all over Europe but Sadi saw them as largely inefficient. He wanted to build a good steam engine in France.

Sadi was almost convinced that one of the reasons for France being left behind than the rest of Europe, particularly Britain, was because of the French country’s inability to make proper use of steam. He began writing his famous book titled Reflections on the Motive Power of Fire in the early 1820s.

There had been several publications that dealt with the workings of a steam engine but Sadi thought they were of no use to the general public with no deep background in science or mathematics. Hence, he took the charge of explaining the essence of the process but did not go into the mechanical and complex details. The book also had a description of the Carnot Cycle.

He observed in his book that the motive power in a steam engine is produced when the heat is made to lower the temperature of the condenser from the higher temperature of the boiler. In that way, he experimented with the caloric theory of heat. However, he wrongly assumed in his book that heat was a gas which was indestructible and also cannot be created. However, he was also sceptical about this theory even when he was writing it in his book. Though he correctly theorized that the efficiency of a steam engine was solely dependent on its coldest and the hottest parts. It was widely assumed that it was the substance, fluid or steam, that was the element driving the entire mechanism of the steam engine.

The book was not popular until almost a decade after it was published. The book was favourably reviewed by the Academy of Sciences and was also popular among the press, where it was praised for its simple tone. There were many reasons for its initial failure. Scientific books had no big market in France and very limited copies of the book went into circulation initially. Also, England was known to be the centre of steam engine research and no one could believe that a Frenchman’s research on the subject could be any good.

Sadi’s research on thermodynamics became the basic principles later on for the construction of automobiles and a steam engine.

In 1834, an engineer named Emile Clapeyron quoted a lot of things from Sadi’s book and extended his studies. Quickly, Sadi’s work in thermodynamics spread across Europe and was further popularized by the German engineer Rudolf Clausius and a British engineer named William Thomson.

In 1827, Sadi was recalled to do full-time duty in the military. However, he had begun severely disinterested by then and after serving a year in the military, he retired permanently.

In the later years of his life, he became more interested in politics. Being a Republican, he was pleased with the results of the 1830 Revolution in France. He attempted to do some work towards the public education system. Before he could establish himself in French politics, he passed away.

Personal Life & Death

There has been no confirmed report of Sadi Carnot ever having a wife.

During the early 1830s, the cholera epidemic was spreading through France. In June 1832, Sadi had fallen ill. He could not regain his strength and when he contracted cholera in August, he passed away within a day, on August 24, 1832. He was only 36 years old at the time of his death.

Cholera was highly contagious. Hence most of his writings and belongings were buried with him. Hence, only a handful of his work survives to this day.

See the events in life of Nicolas Léonard Sadi Carnot in Chronological Order

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