PERRIN, JEAN. - "THE ATOM OF THE CHEMISTS IS NOW A REALITY"

L'agitation moléculaire et le mouvement brownien. (+) La loi de Stokes et le mouvement brownien. Note. (+) L'origine du mouvement brownien. Note. (+) Grandeur des molécules et charge de l'electron. (+) Mouvement brownien et constantes moléculaire (together with Dobrowski). (+) Le mouvement brownien de rotation. (+) Le determinations des grandeurs moléculaires. (+) Les grandeurs moléculaires (nouvelles mesures). (8 Papers).

(Paris, Gauthier-Villars), 1908, 1909, 1911. 4to. No wrappers. In: "Comptes Rendus Hebdomadaires des Séances de L'Academie des Sciences", Tome 146, No 19. Pp. (951-) 1002. Tome 147, Nos 10, 12 a. 14. Pp. (467-) 482, (507-) 546 a. (579-) 610. Tome 149, Nos 10 a. 13. Pp. (473-) 492 a. (541-) 556. Tome 152, Nos 18 a. 21. Pp. (1133-) 1196 a. (1361-) 1432. (8 entire issues offered). Perrin's papers. pp. 967-70, 477-479, 549-51, 475-476, 530-32, 594-596, 477-479, 549-551, 1165-1168 a. 1380-82. Clean and fine.

First appearance of these 8 papers constituting Perrin's major work on the Brownian motion and establishing THE REALITY OF THE MOLECULAR-KINETIC VIEW OF MATTER. Perrin's experimental verification of molecular reality and his 'classical' verification of the statistical method was of great importece to the subsequent rise of the quantum revolution with the introduction of quantum mechanics. Perrin's experiments helped to confirm Einstein's analysis of the Brownian movements (1905), and calculated a value for Avogadro's numbers and thereby the size of atoms and molecules.

Perrin was awarded the Nobel Prize in physics, 1926 "for his work on discontinuity in the structure of matter, and in particular for his discovery of the equilibrium of sedimentation"

"The work for which Perrin is best known is his investigation of Brownian motion, the erratic movements performed by microscopic particles in suspension in a fluid, now interpreted as being caused by the continous, irregular bombardment of the particles by the molecules of the surrounding medium. Perrin thought that collodially suspended particles undergoing Brownian motion would distribute themselves vertically in a definite way at equilibrium. By counting small particles of gum resin suspended in water, Perrin found that their number decreased exponentially with increasing height. He proved that this variation follows from kinetic theory and that from it he could calculate a value for Avogadro's number. Since the size of a water molecule appeared in the equation for the vertical distribution of the brownian motion particles, for the first time the sizes of atoms and molecules could be calculated from actual observations. As henri Poincaré wrote: "The brilliant determination of the number of atom (in a mole) made by Perrin has completed the triumph of atomism.... The atom of the chemists is now a reality.' " (Weber "Pioneers of Science. Nobel Prize Winners in Physics", pp. 80 ff).

Parkinson "Breakthroughs", 1908 C a. 1908 P.

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