The ArgumentEtienn-François Geoffroy' Table des Rapports is generally regarded as a landmark in the evolution of chemistry during the eighteenth century. Issues have arisen among historians concerning the significance and originality of the Table that require fuller attention to the immediate context of chemical research in the Academie des sciences during the two decades that preceded its appearance. The present paper argues that, despite the transition from communal to individual research projects that marked the reorganization of the Academy in 1699, (...) chemists continued to pursue shared problems within a communal ethos. The interactions between Wilhelm Homberg, Etienne-François Geoffroy, and Louis Lemery were particularly prominent. The paper traces one example of this interaction, involving the sulfur principle and its influence on one entry in Geoffroy's Table. Further such studies are needed to elucidate the relation between the concepts of chemical composition and reactions implied in Geoffroy's table and the concepts embodied in the previous work of Geoffroy and his associates in the Academy. (shrink)

After Lavoisier's execution, the leading French chemists were Antoine-François Fourcroy , Louis-Bernard Guyton de Morveau and Claude-Louis Berthollet . At the beginning of the nineteenth century, Berthollet introduced a new conception of chemical change that challenged the theory of elective affinities which had dominated chemistry for nearly a hundred years. Berthollet's new affinities raised controversy among chemists and had to coexist with the firmly established theory of elective affinities. Apart from the public debate in research articles, Berthollet's affinities also had (...) to compete with the influence of Fourcroy and his school in the textbook market. This paper seeks to assess the extent to which French textbooks published at the beginning of the nineteenth century were committed to Berthollet's innovation, and how they contributed to its marginalization. (shrink)

Etienne-François Geoffroy, l’un des chimistes français les plus importants du début du XVIIIe siècle, entretenait des relations régulières avec l’Angleterre. Il était chargé de développer les échanges entre l’Académie royale des sciences et la Royal Society de Londres. Quand il publia sa « Table des rapports entre les substances chimiques » en 1718, Fontenelle et quelques autres lui reprochèrent d’avoir introduit en chimie le système des attractions newtoniennes. Mais en fait, Geoffroy s’est toujours tenu à l’écart aussi bien du mécanisme (...) cartésien que du newtonianisme, le recours aux expériences et à la littérature alchimique constituant ses seules sources d’inspiration. Geoffroy apparaît ainsi comme le représentant d’une chimie empirique, soucieuse de conserver l’autonomie de sa discipline. (shrink)

Summary The first systematic studies on the velocity of chemical reactions (now called reaction rates) were published in the 1850s and 1860s. Inquiring about the course of chemical change, their authors established empirical equations on the basis of their measurement results. But these laws, which represented reaction velocities as proportional to the actual concentration of the reagents, could not be given a physical foundation. The chemists themselves regarded their propositions as mere ad hoc hypotheses. In 1867 Leopold Pfaundler formulated a (...) qualitative theory of chemical processes based on Clausius's version of the kinetic gas theory (and more specifically on his theory of evaporation), and on Saint-Claire Deville's investigations of dissociation processes. Pfaundler's theory was based on farreaching analogies: between evaporation and dissociation; between the gaseous state and the activated state; and between evaporation- and chemical-equilibrium. Four points of Pfaundler's theory must be regarded as essential: (1) the reduction of chemical change to randomly occurring molecular collisions, only showing regularities in great numbers according to the laws of probability; (2) the idea that molecules are in different states of internal and external motion, which determines whether a collision results in a reaction; (3) the view of the reaction step as a transition from internal to external motion and vice versa; and (4) the introduction of a new molecular-kinetic definition of chemical affinity as the maximum of internal motion. With these assumptions, Pfaundler provided the empirical rate equations with a new statistical interpretation and a physical Justification. (shrink)

The focus of this contribution lies on eighteenth-century chemistry up to Lavoisier’s anti-phlogistic chemical system. Some main features of chemistry in this period will be examined by discussing classificatory practices and the understanding of the substances these practices imply. In particular, the question will be discussed of whether these practices can be regarded as natural historical practices and, hence, whether chemistry itself was a special natural history (part I). Furthermore, discussion of the famous Methode de nomenclature chimique (1787) raises the (...) question of what modes of classification tell us about chemists’ understanding of the substances they deal with (part II). Finally, in investigating what taxonomic orders reveal about deep structures of chemists’ understanding of the world of substances, the contribution will examine the question of whether Lavoisier’s anti-phlogistic chemical system was a revolution on the level of a deep structure or a revision within the untouched frame of such a structure (part III). (shrink)

Although not universally accepted at the time, the atomic hypothesis during the 19th century provided a definite ordering scheme for certain relatively sophisticated chemical phenomena. As such, it was conceptually responsible for the formulation and precise articulation of important seminal ideas in chemical studies. In this paper we will explore this claim with regard to the views of the British chemist Alexander W. Williamson.