Jean Baptiste Perrin

Jean Baptiste Perrin ForMemRS[1] (30 September 1870 – 17 April 1942) was a French physicist who, in his studies of the Brownian motion of minute particles suspended in liquids, verified Albert Einstein’s explanation of this phenomenon and thereby confirmed the atomic nature of matter (sedimentation equilibrium). For this achievement he was honoured with the Nobel Prize for Physics in 1926.[2]

Jean Baptiste Perrin
Jean Perrin 1926
Perrin in 1926
Born30 September 1870
Died17 April 1942 (aged 71)
Alma materÉcole Normale Supérieure
University of Paris
Known forNature of cathode rays
Brownian motion
AwardsMatteucci Medal (1911)
Nobel Prize in Physics (1926)
Scientific career
InstitutionsÉcole Normale Supérieure
University of Paris
Jean Baptiste Perrin-signature-2


Early years

Born in Lille, France, Perrin attended the École Normale Supérieure, the elite grande école in Paris. He became an assistant at the school during the period of 1894–97 when he began the study of cathode rays and X-rays. He was awarded the degree of docteur ès sciences (PhD) in 1897. In the same year he was appointed as a lecturer in physical chemistry at the Sorbonne, Paris. He became a professor at the University in 1910, holding this post until the German occupation of France during World War II.

Research and achievements

Jean Perrin 1908
Jean Perrin in 1908

In 1895, Perrin showed that cathode rays were of negative electric charge in nature. He determined Avogadro's number (now known as the Avogadro constant) by several methods. He explained solar energy as due to the thermonuclear reactions of hydrogen.

After Albert Einstein published (1905) his theoretical explanation of Brownian motion in terms of atoms, Perrin did the experimental work to test and verify Einstein's predictions, thereby settling the century-long dispute about John Dalton's atomic theory. Carl Benedicks argued Perrin should receive the Nobel Prize in Physics; Perrin received the award in 1926 for this and other work on the discontinuous structure of matter, which put a definite end to the long struggle regarding the question of the physical reality of molecules.[3]

Perrin was the author of a number of books and dissertations. Most notable of his publications were: "Rayons cathodiques et rayons X" ; "Les Principes"; "Electrisation de contact"; "Réalité moléculaire"; "Matière et Lumière"; "Lumière et Reaction chimique".

Perrin was also the recipient of numerous prestigious awards including the Joule Prize of the Royal Society in 1896 and the La Caze Prize of the French Academy of Sciences. He was twice appointed a member of the Solvay Committee at Brussels in 1911 and in 1921. He also held memberships with the Royal Society of London and with the Academies of Sciences of Belgium, Sweden, Turin, Prague, Romania and China. He became a Commander of the Legion of Honour in 1926 and was made Commander of the Order of Léopold (Belgium).

In 1919, Perrin proposed that nuclear reactions can provide the source of energy in stars. He realized that the mass of a helium atom is less than that of four atoms of hydrogen, and that the mass-energy equivalence of Einstein implies that the nuclear fusion (4 H → He) could liberate sufficient energy to make stars shine for billions of years.[4] A similar theory was first proposed by American chemist William Draper Harkins in 1915.[5][6] It remained for Hans Bethe and Carl Friedrich von Weizsäcker to determine the detailed mechanism of stellar nucleosynthesis during the 1930s.[7]

In 1927, he founded the Institut de Biologie Physico-Chimique together with chemist André Job and physiologist André Mayer. Funding was provided by Edmond James de Rothschild.[8] In 1937, Perrin established the Palais de la Découverte, a science museum in Paris.

Perrin is considered the founding father of the National Centre for Scientific Research (Centre National de la Recherche Scientifique (CNRS)). Following a petition by Perrin signed by over 80 scientists, among them eight Nobel Prize laureates, the French education minister set up the Conseil Supérieur de la Recherche Scientifique (French National Research Council) in April 1933. In 1936, Perrin, now an undersecretary for research, founded the Service Central de la Recherche Scientifique (French Central Agency for Scientific Research).[8] Both institutions were merged under the CNRS umbrella on October 19, 1939.[9]

His notable students include Pierre Victor Auger. Jean Perrin was the father of Francis Perrin, also a physicist.

Personal life

Perrin was an atheist and a socialist.[10] He was an officer in the engineer corps during World War I. When the Germans invaded France in 1940, he escaped to the U.S.A., together with his partner Nine Choucroun. He died in New York City. After the War, in 1948, his remains were transported back to France by the cruiser Jeanne d'Arc and buried in the Panthéon.


  1. ^ Townsend, J. S. (1943). "Jean Baptiste Perrin. 1870-1942". Obituary Notices of Fellows of the Royal Society. 4 (12): 301–326. doi:10.1098/rsbm.1943.0004.
  2. ^ Kyle, R. A. (1979). "Jean Baptiste Perrin". JAMA: the Journal of the American Medical Association. 242 (8): 744. doi:10.1001/jama.242.8.744.
  3. ^ Mauro Dardo (2004). Nobel Laureates and Twentieth-Century Physics. Cambridge University Press. pp. 114–116. ISBN 0521540089. Retrieved 13 February 2014.
  4. ^ Why the Stars Shine D.Selle, Guidestar (Houston Astronomical Society), October 2012, p.6-8
  5. ^ N.C.Panda (1991). Māyā in Physics. Motilal Banarsidess (Delhi). p. 173. ISBN 81-208-0698-0.
  6. ^ Robert S. Mulliken (1975). "William Draper Harkins 1873 - 1951" (PDF). Biographical Memoirs. National Academy of Sciences. 47: 48–81.
  7. ^ John North, Cosmos: An Illustrated History of Astronomy and Cosmology (University of Chicago Press, p.545)
  8. ^ a b Zeitoun, Charline (September 2009). "Le CNRS a 70 ans". CNRS le journal. Retrieved February 23, 2012.
  9. ^ Guthleben, Denis (November 3, 2010). "Un peu d'histoire... La création du CNRS". Comité pour l’histoire du CNRS. Retrieved February 23, 2012.
  10. ^ Bernard Valeur, Jean-Claude Brochon (2001). New Trends in Fluorescence Spectroscopy: Applications to Chemical and Life Sciences. Springer. p. 17. ISBN 978-3-540-67779-6. Jean and Francis Perrin held similar political and philosophical ideas. Both were socialists and atheists.CS1 maint: Uses authors parameter (link)

External links

1870 in France

Events from the year 1870 in France.

1926 in science

The year 1926 in science and technology involved some significant events, listed below.

1942 in France

Events from the year 1942 in France.

8116 Jeanperrin

8116 Jeanperrin, provisional designation 1996 HA15, is a Florian asteroid and synchronous binary system from the inner regions of the asteroid belt, approximately 4.8 kilometers (3 miles) in diameter. It was discovered on 17 April 1996, by Belgian astronomer Eric Elst at the La Silla Observatory in northern Chile. The likely stony S-type asteroid has a rotation period of 3.62 hours and a nearly round shape. It was named for French physicist and Nobel laureate Jean Baptiste Perrin. A minor-planet moon, a third the size of its primary, was discovered in 2007.

Avogadro constant

The Avogadro constant, named after scientist Amedeo Avogadro, is the number of constituent particles, usually molecules, atoms or ions that are contained in the amount of substance given by one mole. It is the proportionality factor that relates the molar mass of a substance to the mass of a sample, is designated with the symbol NA or L, and has the value 6.022140857(74)×1023 mol−1 in the International System of Units (SI).Previous definitions of chemical quantity involved the Avogadro number, a historical term closely related to the Avogadro constant, but defined differently: the Avogadro number was initially defined by Jean Baptiste Perrin as the number of atoms in one gram-molecule of atomic hydrogen, meaning one gram of hydrogen. This number is also known as Loschmidt constant in German literature. The constant was later redefined as the number of atoms in 12 grams of the isotope carbon-12 (12C), and still later generalized to relate amounts of a substance to their molecular weight. For instance, the number of nucleons (protons and neutrons) in one mole of any sample of ordinary matter is, to a first approximation, 6×1023 times its molecular weight. Similarly, 12 grams of 12C, with the mass number 12 (6 protons, 6 neutrons), has a similar number of carbon atoms, 6.022×1023. The Avogadro number is a dimensionless quantity, and has the same numerical value of the Avogadro constant when given in base units. In contrast, the Avogadro constant has the dimension of reciprocal amount of substance. The Avogadro constant can also be expressed as 0.6023... mL⋅mol−1⋅Å−3, which can be used to convert from volume per molecule in cubic ångströms to molar volume in millilitres per mole.

Pending revisions in the base set of SI units necessitated redefinitions of the concepts of chemical quantity. The Avogadro number, and its definition, was deprecated in favor of the Avogadro constant and its definition. Based on measurements made through the middle of 2017 which calculated a value for the Avogadro constant of NA = 6.022140758(62)×1023 mol−1, the redefinition of SI units is planned to take effect on 20 May 2019. The value of the constant will be fixed to exactly 6.02214076×1023 mol−1.

Charles Perrin

Charles Jean Baptiste Perrin (6 July 1875 – 26 March 1954) was a French rower who competed in the 1900 Summer Olympics.

He was part of the French boat Club Nautique de Lyon, which won the silver medal in the coxed four.

Council of Ancients

The Council of Ancients or Council of Elders (French: Conseil des Anciens) was the upper house of French legislature under the Constitution of the Year III, during the period commonly known as the Directory (French: Directoire), from 22 August 1795 until 9 November 1799, roughly the second half of the period generally referred to as the French Revolution.

The Council of Ancients was the senior of the two halves of the republican legislative system. The Ancients were 250 members who could accept or reject laws put forward by the lower house of the Directory, the Council of Five Hundred (Conseil des Cinq-Cents). Each member had to be at least forty years of age, and a third of them would be replaced annually. They had no authority to draft laws, but any bills that they renounced could not be reintroduced for at least a year.Besides functioning as a legislative body, the Ancients chose five Directors, who jointly held executive power, from the list of names put forward by the Council of Five Hundred. The Council of Ancients had their own distinctive official uniform, with robes, cape and hat, just as did the Council of Five Hundred and the Directors. Under the Thermidorean constitution, as Boissy d'Anglas put it, the Council of Five Hundred was to be the imagination of the Republic, and the Council of Ancients its reason.The name adopted for the body was based on the French translation/adaptation of the term Senate .

Jean Baptiste Perrin (fl. 1786)

Jean Baptiste Perrin (fl. 1786–1798) was a tutor and educational author. Born in France, he moved to Dublin and became a teacher of French. He often resided for months at a time in the houses of such of the Irish gentry as desired to acquire a knowledge of the French tongue.

He mixed in the political agitations of the period, and on 26 April 1784 was elected an honorary member of the Sons of the Shamrock; and is said in 1795 to have joined in the invitation to the French government to invade Ireland. In his later years he resided at Leinster Lodge, near Athy, County Kildare. The date of his death is not given; but he was buried in the old churchyard at Palmerstown.

He had at least one child, Louis Perrin, a judge, who was born at Waterford in 1782.

List of Légion d'honneur recipients by name (P)

The following is a list of some notable Légion d'honneur recipients by name. The Légion d'honneur is the highest order of France. A complete, chronological list of the members of the Legion of Honour nominated from the very first ceremony in 1803 to now does not exist. The number is estimated at one million including about 3,000 Grand Cross.

List of streets at CERN

The European Organization for Nuclear Research (CERN) is an international, intergovernmental organisation. Its activities are carried out on land placed at its disposal by the Canton of Geneva, the Swiss Confederation and France. In accordance with the agreements reached between France, Switzerland and CERN governing the organisation's legal status, the CERN site is placed under the authority and control of the Director-General as the organisation's chief executive officer. The latter is thus empowered to issue internal rules applicable to all persons entering the CERN site and intended to establish thereon the conditions necessary for the exercise of its functions.

CERN street names were for a long time an internal matter to the organisation. In 2013 the Canton of Geneva officially recognised CERN street names.

Oblate spheroidal coordinates

Oblate spheroidal coordinates are a three-dimensional orthogonal coordinate system that results from rotating the two-dimensional elliptic coordinate system about the non-focal axis of the ellipse, i.e., the symmetry axis that separates the foci. Thus, the two foci are transformed into a ring of radius in the x-y plane. (Rotation about the other axis produces prolate spheroidal coordinates.) Oblate spheroidal coordinates can also be considered as a limiting case of ellipsoidal coordinates in which the two largest semi-axes are equal in length.

Oblate spheroidal coordinates are often useful in solving partial differential equations when the boundary conditions are defined on an oblate spheroid or a hyperboloid of revolution. For example, they played an important role in the calculation of the Perrin friction factors, which contributed to the awarding of the 1926 Nobel Prize in Physics to Jean Baptiste Perrin. These friction factors determine the rotational diffusion of molecules, which affects the feasibility of many techniques such as protein NMR and from which the hydrodynamic volume and shape of molecules can be inferred. Oblate spheroidal coordinates are also useful in problems of electromagnetism (e.g., dielectric constant of charged oblate molecules), acoustics (e.g., scattering of sound through a circular hole), fluid dynamics (e.g., the flow of water through a firehose nozzle) and the diffusion of materials and heat (e.g., cooling of a red-hot coin in a water bath)

Oskar Klein

Oskar Benjamin Klein (Swedish: [ˈklajn]; 15 September 1894 – 5 February 1977) was a Swedish theoretical physicist.

Palais de la Découverte

The Palais de la Découverte ("Discovery Palace") is a science museum located in the Grand Palais, in the 8th arrondissement on Avenue Franklin D. Roosevelt, Paris, France. It is open daily except Monday; an admission fee is charged.

The museum was created in 1937 by Jean Baptiste Perrin (awarded the Nobel Prize in Physics, 1926) during an international exhibition on "Arts and techniques in modern life". In 1938 the French government decided to convert the facility into a new museum, which now occupies 25,000 square metres within the west wing of the Grand Palais (Palais d'Antin) built for the Exposition Universelle (1900) to designs by architect Albert-Félix-Théophile Thomas.

In January 2010 the museum was merged with the Cité des Sciences et de l'Industrie under one institution is named universcience with two locations.

Today the museum contains permanent exhibits for mathematics, physics, astronomy, chemistry, geology, and biology, featuring interactive experiments with commentaries by lecturers. It includes a Zeiss planetarium with 15-metre dome.

Perrin friction factors

In hydrodynamics, the Perrin friction factors are multiplicative adjustments to the translational and rotational friction of a rigid spheroid, relative to the corresponding frictions in spheres of the same volume. These friction factors were first calculated by Jean-Baptiste Perrin.

These factors pertain to spheroids (i.e., to ellipsoids of revolution), which are characterized by the axial ratio p = (a/b), defined here as the axial semiaxis a

(i.e., the semiaxis along the axis of revolution) divided by the equatorial semiaxis b. In prolate spheroids, the axial ratio p > 1 since the axial semiaxis is longer than the equatorial semiaxes. Conversely, in oblate spheroids, the axial ratio p < 1 since the axial semiaxis is shorter than the equatorial semiaxes. Finally, in spheres, the axial ratio p = 1, since all three semiaxes are equal in length.

The formulae presented below assume "stick" (not "slip") boundary conditions, i.e., it is assumed that the velocity of the fluid is zero at the surface of the spheroid.

René Marcelin

René Marcelin (12 June 1885-24 September 1914) was a French physical chemist, who died in World War I at a young age. He was a pupil of Jean Baptiste Perrin at the Faculty of Sciences in Paris and performed theoretical studies in the field of chemical kinetics.

Rutherford model

The Rutherford model, also known as planetary model is a model which tried to describe an atom devised by Ernest Rutherford. Rutherford directed the famous Geiger–Marsden experiment in 1909 which suggested, upon Rutherford's 1911 analysis, that J. J. Thomson's plum pudding model of the atom was incorrect. Rutherford's new model for the atom, based on the experimental results, contained new features of a relatively high central charge concentrated into a very small volume in comparison to the rest of the atom and with this central volume also containing the bulk of the atomic mass of the atom. This region would be known as the "nucleus" of the atom.

Sedimentation equilibrium

Sedimentation equilibrium in a solution or suspension of different particles, such as molecules, exists when the rate of transport of each material in any one direction due to sedimentation equals the rate of transport in the opposite direction due to diffusion. Sedimentation is due to an external force, such as gravity (for very large particles) or centrifugal force in a centrifuge.

Modern applications use the analytical ultracentrifuge. The theoretical basis for the measurements is developed from the Mason-Weaver equation. The advantage of using analytical sedimentation equilibrium analysis for Molecular Weight of proteins and their interacting mixtures is the avoidance of need for derivation of a frictional coefficient, otherwise required for interpretation of dynamic sedimentation.

It was discovered for large particles by Jean Baptiste Perrin for which he received the Nobel Prize in Physics in 1926.

William Draper Harkins

William Draper Harkins (December 28, 1873 – March 7, 1951) was a U.S. chemist, notably for his contributions to nuclear chemistry. Harkins researched the structure of the atomic nucleus and was the first to propose the principle of nuclear fusion, four years before Jean Baptiste Perrin published his theory in 1919-20. His findings enabled, among other things, the development of the H-bomb.

Harkins was born in Titusville, Pennsylvania.

Harkins graduated with a PhD from Stanford University in 1907, and subsequently taught chemistry at the University of Montana from 1900 to 1912. He spent the rest of his career at the University of Chicago.

Harkins correctly predicted the existence of the neutron in 1920 (as a proton–electron complex) and was the first to use the word "neutron" in connection with the atomic nucleus. The neutron was detected experimentally by James Chadwick in 1932.

In the beginning of the 1930s, Harkins built a cyclotron. From experiments with this, he concluded that the sun might be powered by nuclear fusion. Among other University of Chicago scientists who made use of this cyclotron was Enrico Fermi, who performed neutron diffusion experiments.Since 1978, the magnet yoke of the cyclotron Harkins built has been on display at Fermilab.

Among his students were Lyle Benjamin Borst, Calvin Souther Fuller, Martin Kamen, Samuel Allison, and Robert James Moon, Jr. (1911–1989).

Harkins died in Chicago. He is buried at Oak Woods Cemetery.


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