In this paper, I argue for a distinction between two scales of coordination in scientific inquiry, through which I reassess Georg Simon Ohm’s work on conductivity and resistance. Firstly, I propose to distinguish between measurement coordination, which refers to the specific problem of how to justify the attribution of values to a quantity by using a certain measurement procedure, and general coordination, which refers to the broader issue of justifying the representation of an empirical regularity by means of abstract mathematical (...) tools. Secondly, I argue that the development of Ohm’s measurement practice between the first and the second experimental phase of his work involved the change of the measurement coordination on which he relied to express his empirical results. By showing how Ohm relied on different calibration assumptions and practices across the two phases, I demonstrate that the concurrent change of both Ohm’s experimental apparatus and the variable that Ohm measured should be viewed based on the different form of measurement coordination. Finally, I argue that Ohm’s assumption that tension is equally distributed in the circuit is best understood as part of the general coordination between Ohm’s law and the empirical regularity that it expresses, rather than measurement coordination. (shrink)

Georg Simon Ohm's work in the field of electricity led to what is now considered to be the most fundamental law of electrical circuits, Ohm's Law. Much less known is that only months earlier, Ohm had published another law—one that differed significantly from the now accepted one. The latter entailed a logarithmic relation between the length of the conductor and a parameter that Ohm called “loss of force.” This paper discusses how Ohm came up with an initial law that he (...) felt compelled to correct a few months later. We analyze Ohm's publication as well as his laboratory notes, relating them to our own laboratory experiences while using the replication method to study his work. We also discuss the conceptual background of Ohm's work. We conclude that he was significantly influenced by French studies in the field of electricity, most notably the ones by Charles Augustin Coulomb. (shrink)

General discussions of the appropriate relations between history and philosophy of science must be complemented by examinations of particular studies involving both fields. Martin Curd's attempt to illuminate the rationality of theory change through analysis of the Copernican Revolution is such a study; his work is undercut by serious flaws and actually displays an ahistorical approach. The result misleads both about the Copernican Revolution and the general problem of theory change in science. The study does illustrate several types of failing (...) that can vitiate efforts to bring historical considerations into philosophical discussion, namely, pitfalls in the characterization of theories, arguments, range of choices, and criteria. (shrink)

In the second half of the nineteenth century, gas discharge research was transformed from a playful and fragmented field into a new branch of physical science and technology. From the 1850s onwards, several technical innovations – powerful high-voltage supplies, the enhancement of glass-blowing skills, or the introduction of mercury air-pumps – allowed for a major extension of experimental practices and expansion of the phenomenological field. Gas discharge tubes served as containers in which resources from various disciplinary contexts could be brought (...) together; along with the experimental apparatus built around them the tubes developed into increasingly complex interfaces mediating between the human senses and the micro-world. The focus of the following paper will be on the physicist and chemist Johann Wilhelm Hittorf , his educational background and his attempts to understand gaseous conduction as a process of interaction between electrical energy and matter. Hittorf started a long-term project in gas discharge research in the early 1860s. In his research he tried to combine a morphological exploration of gas discharge phenomena – aiming at the experimental production of a coherent phenomenological manifold – with the definition and precise measurements of physical properties. (shrink)