Famous 19th Century French Scientists

Though French scholar Pierre-Simon Laplace is primarily known for his work on the solar system, his research extended to areas such as mathematics and physics, apart from astronomy. Widely known as the Newton of France, he escaped being executed during the French Revolution, owing to his lack of political views.

Évariste Galois was a French mathematician best remembered for solving a 350-year-old problem when he was still in his teens. His work formed the basis for group theory and Galois theory, two important branches of abstract algebra. Also a political activist, Évariste Galois died at the age of 20 after suffering wounds in a duel.

Joseph Fourier was a French physicist and mathematician best remembered for commencing the investigation of the Fourier series, which is used widely to solve problems of heat transfer and vibrations. Fourier's law of conduction and Fourier transform are named in his honor. Fourier is also said to have discovered the greenhouse effect.

Louis de Broglie was a French aristocrat and physicist who made important contributions to quantum theory. His de Broglie hypothesis, which suggests that all matter has wave properties, is one of the most important features in the theory of quantum mechanics. In 1929, de Broglie was honored with the Nobel Prize for Physics for his work.

Born into an affluent family, French mathematician Adrien-Marie Legendre probably never had to earn a living till the beginning of the French Revolution. Excelling in math and physics, he later contributed to areas such as elliptic functions, developed the least squares method, and lent his name to Legendre polynomials.

Nobel Prize-winning physicist Henri Becquerel is known for his chance discovery of spontaneous radioactivity. Born into a family of scientists, Becquerel had been an engineer and a physics professor earlier. Marie Curie, who shared the Nobel with him and her husband, Pierre, was one of his doctoral students.

French mathematician Augustin-Louis Cauchy was initially a military engineer. In his early days, he and his family escaped the Reign of Terror and settled in Arcueil. He was one of the pioneers of mathematical analysis and made significant contributions to subjects such as error theory, calculus, and complex functions.

A pioneer in crystallography, radioactivity, piezoelectricity, and magnetism, Pierre Curie was a French physicist who won the Nobel Prize in Physics along with Henri Becquerel and Marie Curie. Despite being an atheist, Pierre Curie was fascinated by spiritualism as he believed that spiritual questions deal with physics. 

Known for his pathbreaking Gay-Lussac's Law, French chemist-physicist Joseph Louis Gay-Lussac was also the first, along with his colleague Alexander von Humboldt, to discover that water is composed of one part of oxygen and two parts of hydrogen. His name is one of the 72 that adorn the Eiffel Tower.

French biologist Jean-Baptiste Lamarck acquired his love for plants while serving as a soldier in the French army. Following an injury, he quit his military career but retained his love for botany. He later taught zoology, studied the classification of invertebrates, and also coined the term biology.

Andre Marie Ampere was a French physicist and mathematician. He is best known for being one of the founders of the science of classical electromagnetism. He was a professor at the École Polytechnique and the Collège de France and a member of the French Academy of Sciences. The base SI unit of electric current, the ampere, is named after him. 

A qualified civil engineer, Vilfredo Pareto had initially worked for the railways and the ironworks. However, he gradually deviated to philosophy, sociology, and politics and gained fame for his application of math to economic issues and his introduction of Pareto efficiency. Mind and Society remains his best-known work.

Georges Cuvier was a French zoologist and naturalist. A major figure in the early 19th century's research of natural sciences, Cuvier played an important role in establishing the fields of comparative paleontology and anatomy by comparing fossils with living animals, for which he is sometimes regarded as the founding father of paleontology.

French mathematician Sophie Germain had used the pseudonym M. Le Blanc to get hold of notes from the École Polytechnique, as being a woman, she was not allowed to attend the institute. She later contributed to the number theory and also pioneered the elasticity theory. She died of breast cancer.

French social psychologist Gustave Le Bon is best remembered for his research on crowd psychology. In his iconic work La psychologie des foules, or The Crowd, he stated that people are driven by their emotions and not by their intellect when they act as part of a crowd.

Son of French Revolutionary leader and mathematician Lazare Carnot, Sadi Carnot was an engineer in the French army. He later laid down the Carnot cycle of heat engines. Much of his works were buried with him when he died of cholera at 36, due to the contagiousness of the disease.

Charles Hermite was a French mathematician best remembered for his research on number theory, invariant theory, algebra, elliptic functions, orthogonal polynomials, and quadratic forms. Also an inspiring and influential teacher, Hermite taught Jules Henri Poincaré, who went on to become fa amous mathematician in his own right.

Claude Bernard was a French physiologist whose scientific experiments led to several important discoveries. He is credited with coining the phrase milieu intérieur, which refers to the extracellular fluid (ECF) environment. He also pioneered the use of a blinded experiment to eliminate various experimental biases.

Best known for developing the Langevin dynamics and the Langevin equation, physicist Paul Langevin was also a staunch Communist. Having worked on his doctoral thesis under Pierre Curie, he had formed a connection with Curie’s wife, Marie Curie, which developed into a full-blown love affair after Pierre’s death.

French physicist and mathematician François Arago discovered rotatory magnetism, named Arago's rotations. He is also remembered for his research on the wave theory of light and for the reforms he introduced as the French minister of war and the navy. The Eiffel Tower has his name inscribed on it.

Charles Lucien Bonaparte was a French ornithologist and naturalist. His father Lucien Bonaparte was the brother of Napoleon I, making Charles Lucien Bonaparte the emperor’s nephew. In Luigi Magni's 1990 Italian historical film In the Name of the Sovereign People, Charles was portrayed by Carlo Croccolo.

Léon Foucault was a French physicist remembered for his presentation of the Foucault pendulum. Foucault is credited with measuring the speed of light and discovering eddy currents. He is also credited with coining the term gyroscope. Considered one of the most important physicists from France, Foucault's name is among the 72 names etched on the famous Eiffel Tower in Paris.

Lazare Carnot was a French physicist, mathematician, and politician. His role in the Napoleonic Wars and French Revolutionary Wars earned him the sobriquet Organizer of Victory. Carnot is credited with developing innovative defensive designs for forts, such as the Carnot wall which served as a defensive mechanism against infantry and artillery attack.

Léon Walras was a French mathematical economist and Georgist. He is known for formulating the marginal theory of value independently of William Stanley Jevons. Considered a pioneer in the development of general equilibrium theory, he authored the book Éléments d'économie politique pure. He is also considered one of the three leaders of the marginalist revolution. 

Alexandre Yersin was a physician and bacteriologist. He is credited with co-discovering Yersinia pestis, the bacillus that causes the bubonic plague. Also an agriculturist, Yersin pioneered the cultivation of rubber trees. He is revered by the Vietnamese people because of his association with Hanoi Medical University; a private university in Da Lat is named in his honor.

Along with his brother, Marcel Schlumberger, Conrad Schlumberger formed one of the most well-known geophysicist duos of Germany. A pioneer in petroleum production, he co-established Schlumberger Ltd., one of the world’s largest oil-field service companies, with Marcel. Their technique of oil exploration offered a cheap alternative than the existing coring methods.

French astronomer Urbain Le Verrier revolutionized celestial mechanics by ascertaining the existence of Neptune by mathematical means. Apart from winning the Royal Society of London’s Copley Medal, he had also led the Observatory of Paris as its director. His name remains one of the 72 engraved on the Eiffel Tower.

Initially training to be an apothecary like his father, Joseph Proust later deviated to pharmacy and then to chemistry. He is best remembered for developing the law of definite proportions, also known as the Proust's law, which states that pure chemical compounds always consist of constant proportions of constituent elements.

Étienne-Jules Marey was a French scientist, chronophotographer, and physiologist. He is best remembered for his work which played a major role in the development of physical instrumentation, cardiology, cinematography, aviation, and the science of laboratory photography. Étienne-Jules Marey is widely regarded as a pioneer of photography.

French astronomer Camille Flammarion began his career as a human computer at the Paris Observatory at 16. He believed intelligent beings from Mars had tried to communicate with people on Earth in the past. He also published L'Astronomie and penned sci-fi novels such as Omega: The Last Days of the World.

French mathematician Louis Bachelier was said to be the first to chart a mathematical model for what is now called the Brownian motion. After losing his wine merchant father early in life, he took over the reins of his family business, but he gradually became a pioneer in mathematical finance.

Camille Jordan was a French mathematician best remembered for his influential Cours d'analyse and his foundational work in group theory. He also served as an educator, teaching at prestigious institutions like the Collège de France and École Polytechnique. The asteroid 25593 Camillejordan is named in his honor.

Jean-Henri Fabre was a French entomologist, naturalist, teacher, chemist, physicist, botanist, and author. He is best remembered for his study of insects; Fabre is widely regarded as the father of modern entomology. He is also remembered for his interesting literary work on the lives of insects. Jean-Henri Fabre's life and career inspired the 1951 biographical movie Monsieur Fabre.

Russian-French surgeon Serge Voronoff, or the Monkey Gland Man, stunned everyone by implanting monkey testicles in his patients to cure impotence. He had apparently also injected himself with dog and guinea pig testicle extracts. Unfortunately, the scientific community dismissed his claims as simply the result of placebo effect.

At 13, Marie-Anne Paulze Lavoisier had married lawyer and chemist Antoine Lavoisier. Her mastery of English helped her assist her husband communicate with his collaborators. She also illustrated her husband’s books and eventually negotiated with Joseph Priestley, on his behalf, over the naming of oxygen, which Priestley had discovered.

Born into a family of surgeons, chemist Michel Eugène Chevreul naturally found an interest in science in his early days. His initial work involved separating colored substances from plant tissue and fats from animal tissue. His discoveries revolutionized color painting and also boosted the soap and candle industries.

Henri Moissan was a French chemist and pharmacist. He is best known for his work in isolating fluorine from its compounds, an achievement that earned him the 1906 Nobel Prize in Chemistry. He was one of the original members of the International Atomic Weights Committee. He also made significant contributions to the production of artificial diamonds.

Jean Baptiste Perrin was a French physicist who won the prestigious Nobel Prize for Physics in 1926. He is credited with confirming the atomic nature of matter. Jean Baptiste Perrin also served as a professor at the University of Paris for many years.

Noted for his view that every physical theory should be derivable from thermodynamic first principles, French theoretical physicist Pierre Duhem was also an eminent historian and philosopher of science, producing groundbreaking work in medieval science. Equally known for his work on relation between theory and experiments, he also established that it is impossible to test a scientific hypothesis in isolation.