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Brauner, Bohuslav

Brauner, Bohuslav

(b. Prague, Czechoslovakia, 8 May 1855; d. Prague, 15 February 1935)


Brauner’s family was one of comfortable means, extensive education, and wide–ranging scientific and political interests. His father, Dr. Francis Brauner, was a lawyer and Czech political leader. His mother, Augusta, was the daughter of Karl August Neumann, professor of chemistry at the Prague Technical College. As a boy, Brauner came into contact with the many scientific, intellectual, and political personalities who frequented his parents’s home. He showed an early interest in science and studied at the Czech Polytechnical High School. In 1873 he entered the University of Prague, where he attended courses in chemistry and performed research in metal analysis and organic preparations. Preferring inorganic chemistry, Brauner went to Heidelberg in 1878 to train under Robert Bunsen. He returned to Prague in 1880 to take his doctorate and, still widening his experience, he went to England in that year to work under the direction of Sir Henry Roscoe at Owen’s College, Manchester.

In 1882 Brauner was appointed lecturer in chemistry in the Czech branch of the Charles University, Prague, where gradually his influence made English the language of the laboratory. He rose to docent in 1885, assistant professor in 1890, and full professor in 1897. Brauner played a large part in the construction of a chemical institute, completed in 1904, at the university. He retired from academic life in 1925.

Brauner led an active and athletic life, playing soccer, bicycling, skiing, and hiking. He suffered a thrombosis in 1922, but his health was good and he was not incapacitated. In 1886 Brauner married Ludmilla, the adopted daughter of Professor Safarik, his predecessor in Prague. The couple had two sons and one daughter.

Brauner’s scientific work consisted largely in the exemplification and perfection in the laboratory of Mendeleev’s periodic law and system of classifying the chemical elements, published in 1869. Since the system had many problems—gaps, too many elements for one position, atomic weight anomalies—it was not immediately popular. it was supported in 1875, however, by the discovery of “eka–aluminum” (now called gallium), which Mendeleev had predicted. This finding, by Boisbaudran, convinced Brauner of the validity of Mendeleev’s system. Brauner, who was to become a correspondent and friend of Mendeleev’s, chose as his life’s work the “experimental examination of the problems connected with Mendeleev’s system….”

Brauner began this work by trying to ascentain the atomic weight of beryllium. Its accepted value, 13, was not in agreement with its position in Mendeleev’s periodic table. Working with John I. Watts, Brauner showed that previous measurements wre faulty and that the correct value was 9, thus confirming beryllium’s place at the head of Group II, as Mendeleev had insisted. Thereafter, Brauner devoted most of his attention to determining the proper positions of the rate earth elements. While working on cerium, he produced CeF4•H2O and was thus the first to prepare a salt of quadrivalent cerium. From this compound, he computed cerium’s atomic weight to be 141.1. placing it in Group IV. Later he revised this value to 140.22. From crude ceria, Brauner isolated compounds of other elements and determined their atomic weight: lanthanum, 138.92; praseodymium, 140.9; neodymium, 144.3; samarium, 150.4. This time–consuming, exacting analyis enabled Brauner to conclude that the rare earths are a group of closely related elements which occupy a single place in the periodic table—that between number 57(lanthanum) and number 72 (hafnium). Brauner also studied the atomic weight of tellurium, an anomaly because it was thought to be 128, higher than that of iodine (127), although it was supposed to precede iodine in Mendeleev’s system. Brauner’s value of 127.61 for tellurium, although still an inversion, remains the accepted value today. In the decades following 1900, Brauner revised his earlier atomic weight results and also investigated the weights of tin and thorium.

In other areas, Brauner discussed the position of hydrogen in the periodic table, supporting Medeleev’s assignment of this element to the place above Group I. During his experiments with cerium he became the first to prepare elemental fluorine by a chemical method. When a fluorine–oxygen compound was produced in 1927, he speculated on it composition. when inert gases were discovered in the atmosphere, Brauner was reluctant to recognize them as new elements; he suggested that helium might be an allotrope of hydrogen and that argon might be triatomic nitrogen. He was also interested in astronomy and physiology, and made small contributions in both fields.

In 1888 Brauner advocated the adoption of oxygen (=16) instead of hydrogen (=1) as the standard for calculating atomic weights. Reviving an argument previously put forth by marignac, Brauner claimed that the change would be advantageous, since most of the elements would then have atomic weights closer to a whole number. An international commission for atomic weights formed, at Brauner’s suggestion, to consider the problem decided to use the oxygen standard, starting in 1904. Brauner was a member of the International Committee on chemical Elements from 1921to 1930. In 1921 he made a number of proposals regarding the naming of terms—atomic weight, for example—which had become clouded as a result of the discovery of isotopes, Brauner called for the formation of a subcommittee for atomic weight and served as its first president.

Brauner was invited to contribute sections on atomic weights for Abegg’s Handbuch der anorganischen Chemie, and he spent the years between 1904 and 1913 preparing and translating the necessary materials. In 1906 he wrote a section on rare earth elements for a revised edition of Mendeleev’s Principles of Chemisitry. He collaborated with his assistant, H. Krepelka, on a textbook of qualitative analysis (in Czech)published in 1919. Additionally, he supported a journal, Collection of Czechoslovak chemical communications, which was founded in1929 and was edited by E. Votocek and J. Heyrovsky. As a cultural “neo–Slavist”, Brauner popularized Mendeleev’s ideas and wrote for English journals on the contributions of other Russian scientists.

Brauner received numerous honors in his lifetime. He was a prominent member of the Czech Academy of Science and of Czechslovakia’s National research Council. He was recognized by scientific societies in England, the United States, France, Poland, Russia, and Austria; and he was honored and decorated by the governments of Austria, Yugoslavia, and France.


I. Original Works. An autobiographical source is “D. I. Mendeleef”, in Pokrokova revue(1907). It was translated into English in Collection of Czechoslovak Chemical Communications2 (1930), 219–243; a bibliography of Brauner’s scientific papers precedes it on pp.212–218.

A selected list of Brauner’s scientific papers includes the following: “On the Atomic Weight of Beryllium”, in Philosophical Magazine, 11 (1881), 65–72: “On the Specific Volumes of Oxides,” ibid., 60–65, written with John I. Watts: “Contributions to the Chemistry of Rare Earth Metals”, in Journal of the Chemical Society, 41 (1882), 68–79; 43 (1883), 278–289; 47 (1885), 879–897; The Atomic Weight of Tellurium”, in Journal of the Russian Physical–chemical Society (1883); “The Standard of Atomic Weights, I”, in Chemical News,58 (1888), 307–308; “Experimental Researches on the Periodic Law. I. Tellurium” in Journal of the Chemical Society, 55 (1889), 382–411; “Experimental Studies on the Periodic Law”, in Chemicke listy, 14 (1889), 1–30; “The Standard of Atomic Weights II”, in Chemische Berichte, 22 (1889), 1186–1192; “Fluoplumbates and Free Fluorine”, in Journal of the Chemical Society, 65 (1894), 393–402, and in Czech Academy, Bulletin, 18 (1894), 1–9; “Atomic Weight of Tellurium”, in Journal of the Chemical Society67 (1895), 549–551; “Note on the Gases of the Helium and Argon Type”, in Chemical News, 71 (1895), 271; “On the Compound Nature of Cerium”, in Czech Academy, Bulletin, 2 (1895), 1–6; “contributions to the Chemistry of Thorium; The Atomic Weight of Thorium; On the Compound Nature of Cerium; On Praseodymium and Neodymium”, in Proceedings of the Chemical Society, 14 (1898), 67–72; “Contributions to the Chemistry of Thorium. Comparative Researches on the Oxalates of the Rare Earths”, in Journal of the Chemical Society,73 (1898), 951–985.

Also see “On the Atomic Wight of Lanthanum and the Error of the Sulphate Method for the Determination of the ‘Equivalent’ of the Rare Earths [written with F. Pavlicek]; On the Atomic Weight of Praseodymium; On Praseodymium Tetroxide and Peroxide; Note on Neodymium; Contribution to the Chemistry of Thorium” in Proceedings of the Chemical Society, 17 (1901), 63–68; “On the Position of Hydrogen in the Periodic System”, in Chemical News, 84 (1901), 233–234, and in Czech Academy, Bulletin,34 (1901), 1–4: “Revision of the Atomic Weight of Tin”, in Journal of the American Chemical Society, 42 (1920), 917–925, written with H. Krepelka; “The New International Commission on chemical Elements”, in Chemical News, 123 (1921), 230–232; “Atomic Weight of Silver”, in Nature, 119 (1927), 348, 526; “Oxide of Fluorine or Fluoride of Oxygen?”, ibid., 120 (1927), 842; “Some Phyciologico–optical Experiments,” in Czech Academy, Bulletin, 38 (1929).

II. Secondary Literature. Two biographical sources are Gerald Druce, Two Czech Chemists, Bohuslav Brauner and Frantissek Wald (London, 1944), pp.4–44, bibliography pp. 62–65; and “Obituary of Bohuslav Brauner,” in Nature, 135 (30 Mar. 1935), 497–498.

Susan G. Schacher

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