Ultraviolet radiation is generally considered to have been discovered by Johann Wilhelm Ritter in 1801. In this article, we study the reception of Ritter’s experiment during the first decade after the event—Ritter’s remaining lifetime. Drawing on the attributional model of discovery, we are interested in whether the German physicists and chemists granted Ritter’s observation the status of a discovery and, if so, of what. Two things are remarkable concerning the early reception, and both have to do more with neglect than (...) with reception. Firstly, Ritter’s observation was sometimes accepted as a fact but, with the exception of C. J. B. Karsten’s theory of invisible light, it played almost no role in the lively debate about the nature of heat and light. We argue that it was the prevalent discourse based on the metaphysics of Stoffe that prevented a broader reception of Ritter’s invisible rays, not the fact that Ritter himself made his findings a part of his Naturphilosophie. Secondly, with the exception of C. E. Wünsch’s experiments on the visual spectrum, there was no experimental examination of the experiment. We argue that theorizing about ontological systems was more common than experimenting, because, given its social and institutional situation, this was the appropriate way of contributing to physics. Consequently, it was less clear in 1810 than in 1801 what, if anything, had been discovered by Ritter.Keywords: Johann Wilhelm Ritter; Carl Johann Bernhard Karsten; Christian Ernst Wünsch; Ultraviolet radiation; Conceptions of heat and light. (shrink)

In this paper it is performed a historical account of the theoretical roots that grounded the following four key basic ideas of chemical equilibrium: ‘incomplete reaction’, ‘reversibility’, ‘equilibrium constant’ and ‘molecular dynamics’. These notions developed in nineteenth-century as a consequence of the evolution of the concept of chemical affinity. The discussion begins with the presentation of the earliest affinity table [‘Table des rapports’] published in 1718 by Geoffroy. Afterwards, it is examined Bergman’s compilation. The theory supporting this arrangement assumed that (...) chemical displacement reactions were complete and could not be reversed. It is analysed how Berthollet’s model showed the inadequacy of this view. His new conceptual considerations established that the amount of the substances involved in a reaction was an essential factor determining its direction, which accounted for the early concepts of incomplete reaction and reversibility. Guldberg and Waage specified the role of mass in chemical equilibrium reactions as they considered the concentrations of the chemicals involved, formulating the first chemical equilibrium mathematical equation that approximates what is called nowadays chemical equilibrium constant. Finally, it is presented how Pfaundler was the first to consider the kinetic theory in the interpretation of the macroscopic properties of equilibrium reactions. (shrink)

This paper is concerned with Coleridge's view of science as at once a branch of knowledge and a creative activity, mediating between man and nature, and thereby complementing poetry. Coleridge was well-informed about contemporary science. He stressed the symbolic status of scientific language, the role of scientific genius, and the need in science to rely upon reason rather than the unqualified senses. Kepler and, more recently, John Hunter and Humphry Davy provided his favorite instances of scientific genius, while chemistry—Davy's not (...) Lavoisier's—was poetic. Science and poetry could both rely on reason, the power of language, and faithfulness to nature. (shrink)