Chemistry for Everyone
What’s in a Name? Robert de Levie Department of Chemistry, Bowdoin College, Brunswick ME 04011; rdelevie@bowdoin. edu
Scientists often pride themselves on their rational approach. Yet the scientific tradition is full of less-than-rational aspects of assigning names to chemical discoveries and to inventions deemed sufficiently important to deserve association with a personal name. When scientists are way ahead of their time, as were Boole, with his invention of binary logic, and Mendel, in his discovery of the basic laws of genetics, they are often ignored by their contemporaries. Credit may be assigned later, often posthumously, upon the subsequent rediscovery of their contributions. This is how we now have Boolean algebra and Mendelian genetics. But it does not always work that way, and scientific name-giving is a somewhat arbitrary process, taking place in an environment polarized by personal ambitions and, perhaps, group prejudices. Just like science itself, the assignment of scientific credit (of which name-giving is one particular aspect) is a human process, subject to the associated foibles, as illustrated below. Water Electrolysis About 200 years ago Nicholson published often-quoted papers describing his work with Carlisle on the electrolysis of water (1, 2). Unfortunately, it is much less widely known that water was electrolyzed more than a decade earlier by Paets van Troostwijck and Deiman, two Dutchmen who used spark discharges from static electricity. They published their work in French (3) and German (4 ) as well as Dutch (5). Subsequently, Pearson reported in the Philosophical Transactions (6 ) that he had duplicated their results. Based on his own experiments, Pearson concluded that “The evidence contained under the heads (a)–(e), considered singly and conjunctively, I apprehend, must be admitted by the most rigorous reasoner, to be demonstrative that hydrogen and oxygen gaz were produced by passing electric discharges through water.” There can be no question that Nicholson was intimately familiar with Pearson’s paper: he reproduced it in three installments in his own Journal (7), he contributed comments to its German translation (8), and he published as well as annotated an anonymous discussion of Pearson’s theoretical interpretation in his Journal (9). Yet, in Nicholson’s subsequent papers on this topic (1, 2) the reader will not find any reference to the work of Paets van Troostwijk and Deiman, or to Pearson’s confirmation thereof. Paets van Troostwijk and Deiman used a U-shaped glass tube, with one side sealed. A thin gold wire protruded through the sealed side, while another was inserted through the open end until it reached inside the sealed side and was within a short distance (17 mm) from the first. The entire cell was filled with carefully degassed water, and electric sparks generated with a friction machine were applied to the two gold wires. This led to gas evolution on both wires; the resulting gas was collected in the sealed end of the U-tube. After a while, so much gas had evolved that the top electrode lost contact with the water. The next electrical discharge then 610
formed a spark through the gas and made it recombine completely to water, after which the above sequence would repeat itself. This experiment thus combined electrolysis with product analysis, because Cavendish had already shown in 1781 that a spark discharged in a 1:2 volume mixture of oxygen and hydrogen would yield pure water. An English translation of major parts of the paper of Paets van Troostwijck and Deiman (3) can be found in Ostwald’s Electrochemistry (10). The source of electricity was a series of short spark discharges from a static electricity generator. In such sparks, as in those of lightning, the electrical current changes direction many times during each discharge. Consequently, during these short bursts of electrolysis, hydrogen and oxygen developed alternately on each electrode, and were collected together at the sealed top of the tube. This makes it even more remarkable that Paets van Troostwijk and Deiman not only electrolyzed water, but correctly identified the products of this electrolysis. In the subsequent experiments of Nicholson and Carlisle, the two electrolysis products were separated spatially, as they used the just-then-invented Volta battery, a source of direct rather than oscillatory current. The results of Paets van Troostwijk and Deiman provided a convincing argument in favor of Lavoisier’s new theory, and helped it to displace the phlogiston theory, which, until then, had been the generally accepted model of chemistry. Electrode Kinetics The rate of an electrode reaction typically varies exponentially with the applied potential, a result known as Tafel’s law (11). When both reduction and oxidation must be taken into account, a transfer coefficient must be introduced to apportion the effect of the potential on the two opposing reaction rates. Erdey-Grúz and Volmer were the first to do this, in 1930, when they derived the corresponding rate expression in a paper on the kinetics of the hydrogen electrode (12). Erdey-Grúz, a student of Volmer, later became professor in Budapest and subsequently Secretary of Education of communist-ruled Hungary. Recently, this basic law of electrode kinetics has become known as the Butler–Volmer equation. Butler was a leading British electrochemist, who had indeed attempted to find an answer to this question. But while the idea of splitting the applied potential into a fraction favoring reduction and the remainder favoring oxidation may appear obvious in hindsight, Butler did not find it. In fact, in his 1940 book on electrocapillarity, Butler specifically refers to Erdey-Grúz and Volmer in this respect (13). The first time that the name of ErdeyGrúz was replaced by that of Butler appears to be in the 1970 textbook by Bockris and Reddy (14), but it may have an earlier origin. At any rate, subsequent textbook authors simply copied it, even though Erdey-Grúz was still very much alive at the time.
Journal of Chemical Education • Vol. 77 No. 5 May 2000 • JChemEd.chem.wisc.edu
Chemistry for Everyone
Enzyme Kinetics The kinetics of the enzymatic inversion of sugar were investigated by Henri (15), who formulated and experimentally verified a theoretical expression for it (16 ). More than a decade later, Michaelis and Menten (17) revisited the kinetics of that same system and obtained the same law. That is, indeed, how science is supposed to work, through validation of earlier results. But that law now carries the Michaelis–Menten name, rather than that of its originator, Henri. Data Smoothing A much-quoted paper in chemical data analysis is that of Savitzky and Golay (18), who described an efficient method to smooth equidistant data based on the least-squares technique. However, one can find this method previously described by Sheppard (19), and by Sherriff (20), who included extensive tables of the corresponding convoluting integers. Moreover, it was prominently mentioned in a well-known textbook on numerical analysis by Whittaker and Robinson (21). The ready availability of computers in the 1960s made the Savitzky–Golay paper a timely reminder and led to its widespread application, but credit for the method really belongs elsewhere. Continuous Variation In the spectrophotometric analysis of complexes, a classical way to determine the stoichiometry of a single complex is the method of continuous variation. It was introduced at least three times. Ostromisslensky worked in Moscow and published his results on the 1:1 complex of aniline and nitrobenzene in German (22). Denison did his research in Pietermaritzburg, South Africa, and published in English (23). Sixteen years later, Job published the same result in French (24). It is now often referred to as Job’s method. Double Layer Louis Georges Gouy was a professor of physics at the University of Lyons, who had worked on magnetic effects (the Gouy balance is named after him) and on optical interference phenomena. He then turned his attention to the electrochemical properties of the metal–solution interface, and wrote a series of monumental papers on that topic (25–27 ). Subsequently he developed the theory of the electrical double layer, and reported his model equations for the double layer in contact with solutions of 1,1-electrolytes such as NaCl (28) and, in a related full paper, also for 1,2- and 2,1-electrolytes such as Na2SO4 or CaCl2 (29). Incidentally, it has been claimed (30) that there were really two different scientists, G. Gouy and M. Gouy, because many of Gouy’s papers refer to him as M. Gouy, where M. denotes monsieur, as distinct from madame (Mme) or mademoiselle (Mlle). Several years later, Chapman (31) rederived Gouy’s result for a symmetrical electrolyte, using the same assumptions and, not surprisingly, producing the same result. Chapman formulated the problem neatly, but added nothing that was not already in Gouy’s brief first note (28) on the topic. Yet, in describing the double layer, Chapman’s name is now commonly
associated with that of Gouy. It may be unrelated, but the curious fact remains that Gouy’s results for asymmetrical electrolytes apparently remained unknown, and were rederived by Grahame more than four decades later (32). Mass Action The central law of chemical equilibrium, the mass action law, was formulated in 1864 by two Norwegians, Guldberg (1836–1902) and his brother-in-law, Waage (1833–1900) (33), and subsequently published in French (34). A final, revised form was published in German (35). Shortly after the original publication, Thomsen (36 ) verified it, and subsequently Ostwald reported many additional results supporting the theory of Guldberg and Waage (37). Ostwald had the Norwegian and French papers translated into German, and published them, together with a reprint of the German paper, as volume 104 in his series of classical papers, the Klassiker der exakten Wissenschaften (38). The names of Guldberg and Waage are nowadays little known to undergraduate students. Instead, the application of their law to simple acid-base problems, especially in logarithmic form, is often associated with the names of Henderson (1878–1942) and Hasselbalch (1874–1962). These gentlemen contributed to our understanding of buffer action, and especially to that of carbonate in blood, but had yet to be conceived when Guldberg and Waage published their first paper on the topic (33), and were not even in elementary school when the mass action law found its final, present form (35). A plausible reason for this misnomer might be that the Henderson approximation (39) for the pH of a buffer mixture of a monoprotic acid and its conjugate base can be written in the same form as the Guldberg–Waage law for the dissociation of a weak acid, even though the concentration terms in the Henderson equation have quite different meanings (which is also why it is an approximation). The association with Hasselbalch is even more mysterious: apparently his contribution was to write Henderson’s approximation in logarithmic form. Discussion The above examples are among those I have come across, more or less by accident, and therefore can be but a rather inhomogeneous sampling of a much larger phenomenon. The reasons for these misnomers are not obvious, although one can suspect, and sometimes document, that self-promotion, and perhaps politics or chauvinism, may have played a role. In some cases the authors of the later studies did not refer to the earlier work, even though they were clearly aware of it; in other instances, they may not have known. But, certainly, the subsequent name-givers should have known better. It can be argued that, as far as society is concerned, it doesn’t much matter who gets the credit, as long as, eventually, the insight is shared with the larger community. On the other hand, scientists are human and often crave recognition by their peers. It can give much individual satisfaction to have one’s name attached to a synthesis, an instrument, or a law. Although science can be its own reward, external recognition does count and can be a strongly motivating force. For that reason, society has an interest in making sure that names are
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Chemistry for Everyone
assigned carefully. Name recognition can also be considered as one of the basic (albeit non-remunerative) aspects of intellectual property rights. Especially in the present Webbased age, with its short institutional memory and its dangers of excessive self-promotion, some care should be exercised in properly assigning names on the basis of scientific priority, especially by textbook writers and teachers. Acknowledgment Brian Conway, who worked with J. A. V. Butler from 1949 till 1954, kindly provided the reference to Butler’s book (13). Literature Cited 1. Nicholson, W. Account of the new electrical or galvanic apparatus of sig. Alex. Volta, and experiments performed with the same; Nicholson’s J. Nat. Philos. Chem. Arts 1800, 4, 179–187. 2. Nicholson, W. Beschreibung des neuen electrischen oder galvanischen Apparats Alexander Volta’s, und einiger wichtigen damit angestellten Versuche; Ann. Phys. 1800, 6, 340–359. 3. Paets van Troostwijk, A.; Deiman, J. R. Sur une manière de décomposer l’eau en air inflammable et en air vital; J. Phys. 1789, 35, 369–378. 4. Paets van Troostwijk, A.; Deiman, J. R. Über die Zerlegung des Wassers in brennbare und Lebensluft durch den elektrischen Funken; Ann. Phys. 1790, 2, 130–141. 5. Paets van Troostwijk, A. Schets der nieuwe ontdekkingen omtrent het water; Algem. Mag. Wetensch. Kunst Smaak 1790, 4, 909–941. 6. Pearson, G. Experiments and observations, made with the view of ascertaining the nature of the gaz produced by passing electric discharges through water; Philos. Trans. 1797, 1, 142–158. 7. Pearson, G. Experiments and observations made with a view to ascertaining the nature of the gaz produced by passing electric discharges through water, with a description of the apparatus for these experiments; Nicholson’s J. Nat. Philos. Chem. Arts 1797, 1, 241–248, 299–305, 349–355. 8. Pearson, G. Untersuchungen über die Luft, welche aus dem Wasser durch electrische Funken entwickelt wird; Ann. Phys. 1799, 2, 154–180. 9. A correspondent. Observations on electricity, light, and caloric, chiefly directed to the results of Dr. Pearson’s experiments on electric discharges through water; Nicholson’s J. Nat. Philos. Chem. Arts 1798, 2, 396–400. 10. Ostwald, W. Elektrochemie: ihre Geschichte und Lehre; von Veit: Leipzig, 1896; English translation: Electrochemistry, History and Theory; Amerind: New Delhi, 1980; pp 21–25. 11. Tafel, J. Über die Polarisation bei kathodischer Wasserstoffentwicklung; Z. Phys. Chem. 1905, 50, 641–712. 12. Erdey-Grúz, T. Volmer, M. Zur Frage der Wasserstoffüberspannung; Z. Phys. Chem. 1930, 150, 203–213. 13. Butler, J. A. V. Electrocapillarity, the Chemistry and Physics of Electrodes and Other Charged Surfaces; Methuen: London 1940; p 132. 14. Bockris, J. O’M.; Reddy, A. K. N. Modern Electrochemistry; Plenum: New York, 1970. 15. Henri, V. Über das Gesetz der Wirkung des Invertins; Z. Phys. Chem. 1901, 39, 194–216. 16. Henri, V. Théorie générale de l’action de quelques diastases; C. R. Acad. Sci. 1902, 135, 916–919. 17. Michaelis, L.; Menten, M. L. Die Kinetik der Invertinwirkung;
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Biochem. Z. 1913, 49, 333–369. 18. Savitzky, A.; Golay, M. J. E. Smoothing and differentiation of data by simplified least squares procedures; Anal. Chem. 1964, 36, 1627–1639. 19. Sheppard, W. F. Fitting of polynomial by method of least squares (Solution in terms of differences or sums); Proc. London Math. Soc. 1914, 13(2), 97–108. 20. Sherriff, C. W. M. On a class of graduation formulae; Proc. R. Soc. Edinburgh 1920, 40, 112–128. 21. Whittaker, E., Robinson, G. The Calculus of Observations, a Treatise on Numerical Mathematics, 2nd ed.; Blackie: London, 1924; pp 291–299. Same, 4th ed., 1944. 22. Ostromisslensky, I. Über eine neue, auf dem Massenwirkungsgezetz fussende Analysemethode einiger binären Verbindungen; Chem. Ber. 1911, 44, 268–273. 23. Denison, R. B. Contrbutions to the knowledge of liquid mixtures I: Chemical combination in liquid binary mixtures as determined by a study of property-composition curves; Trans. Faraday Soc. 1912, 8, 20–34. 24. Job, P. Recherches sur la formation de complexes minéraux en solution, et sur leur stabilité; Ann. Chim. 1928, 9(10), 113–134. 25. Gouy, G. Sur la fonction électrocapillaire I; Ann. Chim. Phys. 1903, 29(7 ), 145–241. 26. Gouy, G. Sur la fonction électrocapillaire II; Ann. Chim. Phys. 1906, 8(8), 291–363. 27. Gouy, G. Sur la fonction électrocapillaire III; Ann. Chim. Phys. 1906, 9(8), 75–139. 28. Gouy, G. Sur la constitution de la charge électrique a la surface d’un électrolyte; C. R. Acad. Sci. 1909, 149, 654–657. 29. Gouy, G. Sur la constitution de la charge électrique a la surface d’un électrolyte; J. Phys. 1910, 9(4), 457–468. 30. Habib, M. A.; Bockris, J. O’M. Specific adsorption of ions; In Comprehensive Treatment of Electrochemistry; Bockris, J. O’M.; Conway, B.; Yeager, E., Eds.; Plenum: New York, 1980; Vol. 1, p 139. 31. Chapman, D. L. A contribution to the theory of electrocapillarity; Philos. Mag. 1913, 25, 475–481. 32. Grahame, D. C. Diffuse double layer theory for electrolytes of unsymmetrical valence types; J. Chem. Phys. 1953, 21, 1054– 1060. 33. Guldberg, C. M.; Waage, P. Studier over Affiniteten; Forh. Vid. Selsk. Christiania 1865, 35–45; reprinted in The Law of Mass Action; Bastiansen, O., Ed.; Universitetsforlaget: Oslo, 1964; pp 7–17. 34. Guldberg, C. M.; Waage, P. Études sur les Affinités Chimiques; Brögger & Christie: Christiania (Oslo), 1867. 35. Guldberg, C. M.; Waage, P. Über die chemische Affinität; J. Prakt. Chem. 1879, 127, 69–114. 36. Thomsen, J. Thermochemische Untersuchungen I: Über die Berthollet’sche Affinitätstheorie; Ann. Phys. Chem. 1869, 214, 65–102. 37. Ostwald, W. Volumchemische Studien I: Über die zwischen Säuren und Basen wirkende Verwandtschaft; J. Prakt. Chem. 1877, 124, 385–423. 38. Guldberg, M.; Waage, P. Untersuchungen über die chemischen Affinitäten, Abhandlungen aus den Jahren 1864, 1867, 1879; Ostwalds Klassiker der exakten Wissenschaften, Vol. 104; Engelmann: Leipzig, 1899. 39. Henderson, L. J. Concerning the relationship between the strength of acids and their capacity to preserve neutrality; Am. J. Physiol. 1908, 21, 173–179.
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