Lazare Carnot

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Lazare Carnot
43rd President of the National Convention
In office
20 May 1794 4 June 1794
Preceded by Robert Lindet
Succeeded by Claude-Antoine Prieur-Duvernois
Member of the Committee of Public Safety
In office
14 August 1793 6 October 1794
Director of the French Directory
In office
4 November 1795 5 September 1797
Preceded byNone
Succeeded by Philippe-Antoine Merlin de Douai
Minister of War
In office
2 April 1800 8 October 1800
Preceded by Louis-Alexandre Berthier
Succeeded by Louis-Alexandre Berthier
Minister of Interior
In office
20 March 1815 22 June 1815
Monarch Napoleon I
Preceded by François-Xavier-Marc-Antoine de Montesquiou-Fézensac
Succeeded by Claude Carnot-Feulin
Personal details
Born(1753-05-13)13 May 1753
Nolay, Côte-d'Or
Died2 August 1823(1823-08-02) (aged 70)
Magdeburg, Prussia
Political party Marais
Children Sadi Carnot
Lazare Hippolyte Carnot
ProfessionMathematician, engineer, military commander, politician
Signature Signature de Lazare Nicolas Marguerite Carnot.svg
Lazare Nicolas Marguerite Carnot00.jpg

Lazare Nicolas Marguerite, Count Carnot (13 May 1753 – 2 August 1823) was a French mathematician, physicist and politician. He was known as the Organizer of Victory in the French Revolutionary Wars and Napoleonic Wars.


Education and early life

Born on 13 May 1753 in the village of Nolay, Côte-d'Or, Carnot was the son of local judge and royal notary, Claude Carnot and his wife, Marguerite Pothier. He was the second oldest of seven children. At the age of fourteen, Lazare and his brother were enrolled at the Collège d'Autun, in Burgundy where he focused on the study of philosophy and the classics. He held a strong belief in stoic philosophy and was deeply influenced by Roman civilization. When he turned fifteen, he left the Collège d'Autun to strengthen his philosophical knowledge and study under the Society of the Priests of Saint Sulpice. During his short time with them, he studied logic, mathematics and theology under the Abbe Bison. After being impressed with Lazare's work as a scholar, the Duke D’Aumont (Marquis de Nolay) recommended a military career for the young one. Carnot was soon sent by his father to the Aumont residence to further his education. Here, he was enrolled in M. de Longpres pension school in 1770 until he was ready to enter one of two prestigious engineering and artillery schools in Paris. A year later, in February 1771, he was ranked the third highest among twelve who were chosen out of his class of more than one hundred who took the entrance exams. It was at this point when he entered the École royale du génie de Mézières, appointed as a second lieutenant. Studies at the Mézières included geometry, mechanics, geometrical designing, geography, hydraulics and material preparation. On 1 January 1773 he graduated the school, ranked as a first lieutenant. He was eighteen years old. [1]

It was here where he met and studied with Benjamin Franklin [2] at the age of twenty. He obtained commission as a lieutenant in Louis Joseph, Prince of Condé's engineer corps. At this moment, he made a name for himself both in the line of (physics) theoretical engineering and in his work in the field of fortifications. While in the army, he continued his study of mathematics. In 1784 he published his first work Essay on Machines, which contained a statement that foreshadowed the principle of energy as applied to a falling weight, and the earliest proof that kinetic energy is lost in the collision of imperfectly elastic bodies. This publication earned him the honor of admittance to a literary society. Another turning point was his essay on Vauban in which he praises the engineer on his works while at the same time developing his own career as a writer/engineer. Vauban's work had a profound effect on his work as a general and engineer. In that same year, he also received a promotion to the rank of captain.

Political career

At the outbreak of the French Revolution in 1789, Carnot entered political life. He became a delegate to the Legislature in 1791. While a member of the Legislative Assembly, Carnot was elected to the Committee of Public Instruction. He believed that all citizens should be educated. As a member of that committee, he wrote a series of reforms for the teaching and educational systems, but they were not implemented due to the violent social and economic climate of the Revolution.

After the Legislative Assembly was dissolved, Carnot was elected to the National Convention in 1792. He spent the last few months of 1792 on a mission to Bayonne, organizing the military defense effort in an attempt to ward off any possible attacks from Enlightenment-era Spain. Upon returning to Paris, Carnot voted for the death of King Louis XVI, although he had been absent for the debates surrounding the Trial of Louis XVI. [3]

On 14 August 1793 Carnot was elected to the Committee of Public Safety, where he took charge of the military situation as one of the Ministers of War. [3]

With the establishment of the Directory in 1795, Carnot became one of the five initial directors. For the first year, the Directors did well working harmoniously together as well as with the Councils. However, difference of political views led to a schism between Carnot and Étienne-François Letourneur, followed by François de Barthélemy, on the one side, and the triumvirate of Paul François Jean Nicolas, vicomte de Barras, Jean-François Rewbell, and Louis Marie de La Révellière-Lépeaux on the other side. Carnot and Barthélemy supported concessions to end the war, and hoped to oust the triumvirate and replace them with more conservative men. After Letourneur had been replaced by another close collaborator of Carnot, François de Barthélemy, both of them, alongside many deputies in the Council of Five Hundred, were ousted in the Coup of 18 Fructidor (4 September 1797), engineered by Generals Napoleon Bonaparte (originally, Carnot's protégé ) and Pierre François Charles Augereau. Carnot took refuge in Geneva, and there in 1797 issued his La métaphysique du calcul infinitésimal.

Military accomplishments

Lazare Carnot, a feverishly productive member of the Committee of Public Safety during the Reign of Terror. His part in raising the levee en masse probably saved the French Revolutionary armies from defeat at the hands of their numerically superior opponents. Lejeune-Lazare Carnot.jpg
Lazare Carnot, a feverishly productive member of the Committee of Public Safety during the Reign of Terror. His part in raising the levée en masse probably saved the French Revolutionary armies from defeat at the hands of their numerically superior opponents.

The creation of the French Revolutionary Army was largely due to his powers of organization and enforcing discipline. In order to raise more troops for the war, Carnot introduced conscription: the levée en masse approved by the National Convention was able to raise France's army from 645,000 troops in mid-1793 to 1,500,000 in September 1794. He was the first to execute the modern waging of war with mass armies and strategic planning realized by the Revolution. [2] As a military engineer, Carnot favored fortresses and defensive strategies. [4] He developed innovative defensive designs for forts, including the Carnot wall, called after him. However, with the constant invasions he decided to take his strategic planning to an offensive strike. From his intellect sprang the maneuvers and organization that turned the tides of war from 1793 to 1794. [5] The basic idea was to have a massive army separated into several units that could move more quickly than the enemy and attack from the flanks rather than head on, which had led to resounding defeats before Carnot was elected to the Committee of Public Safety. This tactic was extremely successful against the more traditional tactics of existing European armies. It was his initiative to train the conscripts in the art of war and to place new recruits with experienced soldiers rather than having a massive volunteer army without any real idea of how to wage battle.

Once the problem of troop numbers had been solved, Carnot turned his administrative skills to the supplies that this massive army would need. Many of the munitions and supplies were in short supply: copper was lacking for guns so he ordered church bells seized in order to melt them down; saltpeter was lacking and he called chemistry to his aid; leather for boots was scarce so he demanded and secured new methods for tanning. He quickly organized the army and helped to turn the tide of the war. It added significantly to discontent with the course of the Revolution in still Bourbon-loyalist areas – such as the Vendée, which had broken out in open revolt 5 months earlier – but the government of the time considered it a success, and Carnot became known as the Organizer of Victory. [3] In autumn 1793, he took charge of French columns on the Northern Front, and contributed to Jean-Baptiste Jourdan's victory in the Battle of Wattignies.

Relationship with Maximilien Robespierre and the Jacobin Club

Carnot met Robespierre for the first time in Arras where he was assigned for military duty and shortly after Robespierre finished his legal studies. Both of them were members of the literary and singing "Societe des Rosati." The group was founded in 1778 and was inspired by the works of Chapelle, La Fontaine, and Chaulieu. It was here where they became acquaintances and eventually friends. Robespierre preceded Carnot into the Academy of Arras entering in April 1784 while he entered three years later in 1787.

While being an active member of the Committee of Public Safety in 1794, tensions between Carnot and Robespierre began to rise massively. During his time on the committee, which was heavily radical, Carnot signed a total of 43 decrees and drafted 18 of them. Most of them regarding military tactics and education. [6] Despite leaning on Jacobin beliefs, Carnot was considered the "conservative" of his half. He was not an official member of the radical group and therefore took on his own independent beliefs in regards to many issues. [7] One of these issues included Robespierre's proposal on an egalitarian social system with which he feverishly disagreed. [8]

Although he had taken no steps to oppose the Reign of Terror, he and some other technocrats on the committee, including Robert Lindet and Louis-Bernard Guyton de Morveau, turned on Maximilien Robespierre and his allies during the Thermidorian Reaction by having him arrested. Robespierre was later killed along with 21 of his followers. Shortly after Robespierre's fall, Carnot was charged for his role during the time but the charges were quickly dismissed when he became a member of the Directory.

Relationship with Napoleon Bonaparte

In 1795, Lazare appointed Napoleon Bonaparte as general in chief of the Army of Italy. He is known to be the only member of the Directory to have supported Napoleon during this time. [9]

In 1800 Bonaparte appointed Carnot as Minister of War, and he served in that office at the time of the Battle of Marengo. In 1802 he voted against the establishment of Napoleon's Consular powers for life and the passing of the title to his children, for as Carnot said when speaking of the power necessary to govern a state "If this power is the appendage of a hereditary family it becomes despotic."

After Napoleon crowned himself emperor on 2 December 1804, Carnot's republican convictions precluded his acceptance of high office under the First French Empire, and he resigned from public life. Probably in response to the fall of the fortress of Vlissingen to the British during the Walcheren Campaign in 1809, Napoleon employed Carnot to write a treatise describing how fortifications could be improved, for the use of the École militaire de Metz. Building on the theories of the controversial engineer Montalembert, Carnot advanced ideas on how the long established bastioned system of fortification could be modified for close defense and to allow for counter attack by the besieged garrison.

In 1812, Carnot returned to office in defense of Napoleon during the disastrous invasion of Russia; he was assigned the defense of Antwerp against the Sixth Coalition – he only surrendered on the demand of the Count of Artois, who was the younger brother of Louis XVIII and later Charles X. He was later made a Count of the Empire by Napoleon as Lazare Nicolas Marguerite, Comte Carnot. During the Hundred Days, Carnot served as Minister of the Interior for Napoleon, and was exiled as a regicide during the White Terror after the Second Restoration during the reign of Louis XVIII.

Retirement and legacy

In 1803 Carnot produced his Géométrie de position. This work deals with projective rather than descriptive geometry. Carnot is responsible for initiating the use of cross-ratios: "He was the first to introduce the cross (anharmonic) ratio of four points of a line taking account of its sign, thereby sharpening Pappus' concept. He then proved that this ratio is invariant for the four points obtained by cutting four lines of a pencil of lines with different secants. In this way, he established the harmonic properties of the complete quadrilateral." [10] This approach to geometry was used by Karl von Staudt four decades later to set a new foundation to mathematics.

The Borda–Carnot equation in fluid dynamics and several theorems in geometry are named after him: one that describes a property of the incircle and the circumcircle of triangle, one that describes a relation between triangles and conic sections and one that describes a property of certain perpendiculars on triangle sides.

Published in 1810 under the title "Traité de la Défense des Places Fortes", his ideas on fortification were further developed in the third edition which was published in 1812. An English translation, "A Treatise on the Defence of Fortified Places" was published in 1814. Although few of his proposals were accepted by mainstream engineers, the Carnot wall, a detached wall at the foot of the escarp, became a common feature in fortifications built in the mid-19th century. [11]

He lived in Warsaw, Congress Poland, and then moved to the Kingdom of Prussia, where he died in the city of Magdeburg. Carnot's remains were interred at the Panthéon in 1889, at the same time as those of Marie Victor de La Tour-Maubourg, Jean-Baptiste Baudin, and François Séverin Marceau-Desgraviers.

Carnot survived all the phases of the French Revolution, from its beginnings in 1789 until the fall of Napoleon in 1815. On the social and political front, Carnot was the author of many reforms sought to improve the country. One of these was the proposal for compulsory public education for all citizens. He also penned a proposal for the new Constitution which included the "Declaration of the Duties of the Citizens" that held that there should be not only education but military service for all citizens of France between the ages of twenty and twenty-five. [2] These proposals were in accordance with the Revolutionaries' thinking at the time, which held that men and women should be honored through ability and intelligence rather than through birthright, even though Carnot himself was nobly born.

Work in mathematics and theoretical engineering

Reflexions sur la metaphysique du calcul infinitesimal, 1797 Carnot - Reflexions sur la metaphysique du calcul infinitesimal, 1797 - 72338.jpg
Réflexions sur la métaphysique du calcul infinitésimal, 1797

He also published essays about engineering theory. Essai sur les machines en général won honorable mention from the Academie sur Science of Paris in 1780. It was revised and published in 1783. In this he outlined a mathematical theory of power transmission in mechanical systems. His essay Principes fondamentaux de l'équilibre et du mouvement 1803 was a further revision and expansion of the earlier work. This was "the first theoretical analysis of engineering mechanics". In this "he went on to analyze the movement of energy from one part of the system to another; he found that power is transmitted most efficiently, and the largest amount of useful work done, when friction, turbulence, and other energy wasting factors are kept to a minimum. This was an early and incomplete approach to the general law of conservation of energy." Carnot's son Nicolas Léonard Sadi Carnot was influenced by his father's work when he undertook his research into the thermal efficiency of steam engines.

Lazare Carnot's name is one of the 72 names inscribed on the Eiffel Tower.

Famous offspring


  1. Dupre, Huntley (1892). Lazare Carnot, Republic Patriot. Oxford, O: The Mississippi Valley Press. pp. 5–20.
  2. 1 2 3 Dino De Paoli, Lazare Carnot's Grand Strategy for Political Victory. Executive Intelligence Review (1996)
  3. 1 2 3 Chisholm 1911.
  4. R.R. Palmer, The Twelve Who Ruled. Princeton: Princeton University Press (1941)
  5. S.J. Watson. Carnot.London:The Bodley Head (1954)
  6. Culp, William Maurice (1914). The work of Lazare Carnot in the Committee of Public Safety. hdl:2027/uc2.ark:/13960/t9d50nf2c.
  7. Forrest, Alan (November 1998). "Lazare Carnot".
  8. Soboul, Albert (28 March 2011). "Lazare Carnot". Britannica.
  9. Hicks, Peter (2013). "Lazare Carnot, a forgotten piece in the Napoleon Bonaparte Jigsaw". Napoleonica. La Revue. 16: 64–74. doi:10.3917/napo.131.0064.
  10. B. L. Laptev & B. A. Rozenfel'd (1996) Mathematics of the 19th Century: Geometry, p. 28, Birkhäuser Verlag ISBN   3-7643-5048-2
  11. Lloyd, E. M. (1887), Vauban, Montalembert, Carnot: Engineer Studies, Chapman and Hall, London (pp. 183–195)

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Political offices
Preceded by
Louis Alexandre Berthier
Ministers of War
2 April 1800 – 8 October 1800
Succeeded by
Louis Alexandre Berthier
Preceded by
François Xavier de Montesquiou-Fezensac
Ministers of Interior
20 March 1815 – 22 June 1815
Succeeded by
Claude Carnot-Feulin