Alan J. Rocke

The quiet revolution: Hermann Kolbe and the science of organic chemistry

Organic chemist Hermann Kolbe (1818-1884) is the subject of this vigorously contextualized biography, which combines the approaches of cognitive and social history of science. Kolbe was one of the most outstanding chemists during the remarkable period in which German science, like the wider manifestations of German industrial and political power, rose to a position of world dominance. Rocke portrays Kolbe as a leading actor in the transformation of the institutional and pedagological dimensions of the physical sciences, as well as in the rapid growth of technologically powerful pure sciences. In all these areas there was a sharp inflection point around 1860 when, as Rocke persuasively argues, the primary discipline in the drama was organic chemistry.

Are Robust Estimators Really Necessary

Although there is substantial literature on robust estimation, most scientists continue to employ traditional methods. They remain skeptical about the practical benefit of employing robust techniques and doubt the realism of the long-tailed error distributions commonly employed by their proponents in Monte Carlo studies. In this article a method of comparing the performance of estimators of location is developed and applied to a series of historical data sets in the physical sciences and to a collection of modern analytical-chemistry data sets. Both sets of results suggest that either severely trimmed means or modern robust estimators are required for optimal efficiency.

Hypothesis and experiment in the early development of Kekulé's Benzene theory

Summary This article attempts a contextual study of the origin and early development of August Kekules theory of aromatic compounds. The terminus a quo is essentially August Hofmanns coining of the modern chemical denotation of ‘aromatic’ in 1855; the terminus ad quem is the first full codification of Kekules theory in the sixth fascicle of his Lehrbuch der organischen Chemie, published in the summer of 1866. Kekules theory is viewed in context with the earlier and concurrent experimental work of such chemists as Hermann Kolbe, Friedrich Beilstein, Rudolph Fittig, and Hugo Muller. The reception of the theory is briefly examined. Attention is paid to the role of Kekules molecular models and of his celebrated dream anecdote of the snake that seizes its own tail. The episode is used as a case study for the continuity of scientific progress, and to illustrate the close reciprocal interactions of hypothesis and experiment in the evolution of a scientific theory.

It Began with a Daydream: The 150th Anniversary of the Kekulé Benzene Structure

In January 1865, August Kekulé published his theory of the structure of benzene, which he later reported had come to him in a daydream about a snake biting its tail. Although other theories had been postulated before 1865, Kekulé was the first to identify the correct structure. Kekulés theory resulted in a clear understanding of aromatic compounds and thus had a major impact on the development of chemical science and industry.

Atoms and Equivalents: The Early Development of the Chemical Atomic Theory

Les theories atomiques chimiques de J. Dalton, H. Davy, T. Thomson, W. Wollaston et J. Berzelius. En particulier la periode 1810-1814.

Kekulé’s Benzene Theory and the Appraisal of Scientific Theories

In three papers published in 1865 and 1866, August Kekule, professor of chemistry at the University of Ghent, proposed a theory of the structure of benzene that provided the basis for the first satisfactory understanding of aromatic compounds, a very large and important class of organic substances. It would be difficult to overestimate the impact of these papers. Within a decade most chemists accepted the theory as empirically verified and heuristically invaluable, and within a generation one observer could assert not only that Kekule’s theory was the “most brilliant piece of scientific prediction to be found in the whole of organic chemistry”, but also that “three-fourths of modern organic chemistry is, directly or indirectly, the product of this theory”.1

Origins and spread of the "Giessen Model" in university science.

Abstract In seeking to understand the rise of Justus Liebigs model for research and teaching, three interrelated and overlapping factors intrinsic to his specialty of organic chemistry have not been sufficiently brought into the explanatory field: the discovery of isomers, the novel practice of using “paper tools,” and the “Kaliapparat” method of organic analysis. The existence of these three interacting factors, all of which emerged suddenly and essentially simultaneously around 1830, led to an explosive expansion in the new field of organic chemistry. Moreover, they made it a uniquely positioned context within which to create in Germany the practices that eventually were associated with all modern research universities. For comparative purposes, the spread of the new model to France, and, more briefly, to the United States is also examined here. The eclectic approach used in this paper places greater emphasis on contingencies of time, place, and discipline than many earlier studies of this problem have done; it is thus intended to provide a helpful complementary perspective.

Women and Chemistry in Regency England: New Light on the Marcet Circle

Jane Marcets Conversations on Chemistry (first edition, 1806) was possibly the best-selling English-language chemistry book of the first half of the nineteenth century. Recent scholarship has explored the degree to which her husband assisted in the writing of the book, without diminishing the high merits of the author. Previously unpublished correspondence, some of which appears here for the first time, casts new light on the social and professional circle of Jane and Alexander Marcet, including its influence on Janes book. One of the members of that circle was a hitherto unrecognised but highly capable young female chemist, Frederica Sebright. The story told here underlines the tensions in elite circles in early nineteenth-century England between broad-minded acceptance and patronising limitations for women in science.

CHEMICAL ATOMISM AND THE EVOLUTION OF CHEMICAL THEORY IN THE NINETEENTH CENTURY

The development of chemical theory in the nineteenth century has been relatively little studied, compared with other sciences and other periods; much remains still to be explored. One notable example is chemical atomism, and its adjuncts such as valence and structure theory. Nonexistent at the beginning of the century, a generation or two later these ideas had moved to the very center of the science, which they still inhabit. The chemical atomic theory embodies outstanding examples of paper tools that provide not only explanatory and expository functions for what is already accepted as known, but also heuristic guidance in the further construction of a science. It Olay be of interest, therefore, to attempt an analysis of what some recent studies have revealed about this subject, along with indications of where further historical efforts may yield additional rewards. Let me start with a set-piece taken from the dawn of the theory: the determination of the atomic weight of nitrogen and of the formulas for the simplest nitrogen compounds. The determination of atomic weights from analytical data requires prior assignment of atomistic formulas for the substances analyzed. Dalton assigned formulas using two different principles, both of them derived from physics: first and foremost, his simplicity axioms, and secondarily and pragmatically, vapor densities. I Both of these approaches led Dalton to the NzO, NO, N02 pattern for the three principal nitrogen oxides, and evidence suggests that he was permanently convinced that these were about the most securely established formulas in chemistry.2 He also assigned the HO formula to water, which accorded with simplicity, but created an anomaly for vapor densities. 3 These formula assignments, combined with chemical analysis, enabled Dalton to determine by an indirect route (through their respective oxygen compounds) that nitrogen atoms weigh about five times as much as hydrogen atoms. 4 But the same numerical result could also be obtained directly, through a compound of nitrogen and hydrogen. His simplicity axiom led Dalton to think that the formula for ammonia should be NH, and chemical analysis of ammonia gave the right answer, namely that ammonia contains about five times as much nitrogen as hydrogen. In this way, successful retrodiction, or reticulation, of existing empirical data provided a validating instance for the theory as a whole. Sort of. This particular network of assumptions and evidence was about as leaky as a fishnet. Daltons simplicity axiom was ambiguous for cases of mUltiple proportions, and his application of it conflicted with his vapor-density approach for some of the most central cases. His stance toward vapor densities as an indicator of atomic-molecular weight was always inconsistent. The direct and indirect means of

Theory versus Practice in German Chemistry: Erlenmeyer beyond the Flask

This essay examines the early career of the chemist Emil Erlenmeyer (1825–1909), focusing on his various endeavors in industrial consulting and entrepreneurship, and his eventual decisive turn, in 1862, to academic research and teaching. This case study offers insights into the developing relationship between theory-based academic research and artisanal and industrial practice in the German states during the 1850s and 1860s. Attention is paid to the relevance of this material to the contemporary historiography of “technoscience.”