Molecular Reality (book)

Molecular Reality: A Perspective on the Scientific Work of Jean Perrin is a book by the American historian of science Mary Jo Nye, published in 1972 by Macdonald in London and American Elsevier in New York. It is a study of the French physical chemist Jean Perrin, whose experiments on Brownian motion between 1908 and 1913 persuaded most physicists and chemists that molecules exist. It was Nye's first book.^[1][2] Its subject, the argument over whether atoms and molecules are real, is described in Molecular reality (history of science), and Perrin's own book on the case is Les Atomes.

Jean Perrin (1870 to 1942) was professor of physical chemistry at the Sorbonne. From 1908 he made emulsions of resin grains of equal size, watched them in a microscope, and compared how they settled and wandered with what the kinetic theory predicted for a very heavy gas. He compared the numbers of molecules per mole that this and twelve other kinds of phenomena gave, found them clustered around 6 × 10²³, and received the Nobel Prize in Physics for 1926.^[3][4] The experiments are set out in Les Atomes, Perrin's book of 1913, and the account that Nye wrote of them placed them within the rest of his career.

Nye was born in Nashville in 1944, took a bachelor's degree at the University of Wisconsin in 1965 and a doctorate there in 1970, in its program in the history of science.^[5] After her marriage in 1968 she spent six months doing archival research in France. The book is, in the words of the Oregon State biography, "an outgrowth of her doctoral dissertation", and it appeared two years after she took the degree, when she was a postdoctoral fellow and then a visiting professor at the University of Oklahoma.^[2]

The volume has 201 pages, with a bibliography on pages 180 to 193, and it belongs to the History of Science Library, a series that Macdonald issued.^[6][7] The British Journal for the History of Science reviewed it in November 1974, in a notice of two pages by S. B. Sinclair.^[7]

The Stanford Encyclopedia of Philosophy calls it "a detailed account of Perrin's scientific work and its historical context", and cites it for two particular points.^[8] On pages 111 and 112 Nye shows that Perrin's first work on how Brownian grains thin out with height seems to have been done without knowledge of Albert Einstein's paper of 1905. Einstein's paper was brought to his attention soon afterward, and Perrin acknowledged it in everything he published later. On pages 145 to 152 she documents how Wilhelm Ostwald and others conceded that the experiments had decided the question in favor of atoms. Ostwald, she reports, gave as his reason that Perrin's argument needed only the central assumptions of the kinetic theory, the equipartition of energy and the randomness of molecular motion, and no auxiliary assumptions.^[8]

Nye also wrote on a different side of Perrin, in a paper of 1975, "Science and Socialism: The Case of Jean Perrin in the Third Republic".^[9] Her later books on the history of atomic theory include a compilation of primary sources, The Question of the Atom, from the Karlsruhe congress of 1860 to the first Solvay conference of 1911 (1984).^[5] She received the Dexter Award of the American Chemical Society's Division of the History of Chemistry in 1999 and the Sarton Medal of the History of Science Society in 2006.^[5]

The words are Perrin's. His memoir of 1909, "Mouvement brownien et réalité moléculaire", has a section headed "Molecular reality" that follows a table of the phenomena which, "taken altogether", form "what may be termed the proof of molecular reality". Frederick Soddy's English translation of 1910 is called Brownian Movement and Molecular Reality.^[10] Nye took the last two words. A section of the Stanford Encyclopedia of Philosophy article on atomism is headed "Brownian Motion and Molecular Reality", and George E. Smith and Raghav Seth gave the same words to their book of 2020, which reconsiders what the experiments showed.^[8][11]

Molecular Reality Corporation was founded as demonpore, inc. in 2018 and took its present name in 2021.^[12] The phrase had been the title of a book 49 years earlier. The company's 2022 document Our North Star has a section called "Increasing Awareness of Molecular Reality".^[13]

• Molecular reality (history of science)
• Les Atomes
• Jean Perrin
• Molecular Reality (disambiguation)