This paper concentrates on a debate over dispersion in the second half of the 1830s, in which both sides utilized the same set of experimental data to test a proposed wave account of dispersion, but could not agree on how these data should be used. The conflict regarding experimental data was caused by differences in instruments. In the debate, optical instruments in many ways functioned like paradigms, shaping scientists' opinions. Instruments also led the debate into an impasse, because no apparatus (...) was available for the necessary experimental replication. Because of unreconcilable differences regarding experimental evidence, the wave theory's failure in explaining dispersion did not become an obstacle to its acceptance. (shrink)

In a publication of 1831 later seen as a milestone in the development of chemistry, Justus Liebig announced a new apparatus for the analysis of organic compounds and provided analytical results for fifteen substances. In this paper we used the detailed descriptions published by Liebig in 1837 to reconstruct his apparatus and methods for hydrogen, carbon and nitrogen analysis. Our replications of his analyses of racemic acid, cinchonine, narcotine, and urea reveal that his two pieces of apparatus give excellent results (...) for carbon and hydrogen content, but erratic results for nitrogen. The results corroborate the assessments of Liebig and his contemporaries, and show that the analytical method for carbon and hydrogen analysis was remarkably accurate. We offer this case, with its convincing replicability, not only to clarify the nature of Liebig's innovations, but also as a new model for understanding broader contested issues in the philosophy and sociology of science. Our analysis suggests that the great shift in science from gentlemanly avocation to professional vocation was tightly linked to laboratory practice, and not just to social networks and context. It also provides the basis for a critique of H. M. Collins's theory of the 'experimenters' regress'. (shrink)

This essay is concerned with the epistemic roles of error in scientific practice. Usually, error is regarded as something negative, as an impediment or obstacle for the advancement of science. However, we also frequently say that we are learning from error. This common expression suggests that the role of error is not—at least not always—negative but that errors can make a fruitful contribution to the scientific enterprise. My paper explores the latter possibility. Can errors play an epistemically productive role in (...) scientific research? The paper begins with a review of several twentieth-century approaches to error and the various agendas behind them. It is shown that only very few scholars have considered whether errors can be productive. The main part of the paper examines a concrete debate in early nineteenth-century microscopy and analyses how the microscopists coped with the problem of error. Drawing on this material, the article offers some terminological clarifications of the common notion ‘learning from error’. The conclusion argues that error can indeed play epistemically productive roles in scientific practice.Keywords: Error; Nineteenth-century microscopic anatomy. (shrink)

: This article analyzes the transformation of epistemological and methodological discourses in German microscopy. It is argued that the expansion of microscopy in the early decades of the nineteenth century was pivotal for the emergence of intricate methodologies that characterized the instruments and methods of microscopy in new ways. Close examination of these means of investigation showed them to be intrinsically imperfect. The flaws of the instrument, the faults of the observer's eyes and the obstructive power of the objects of (...) investigation actions came to be crucial issues in epistemological and methodological debates. It became clear that the particulars of the research arrangement not only limited the range of possible microscopical observations but would always impede and interfere with the results: Perfect working conditions could never be achieved. (shrink)

: In 1842, British astronomer Sir John Herschel wrote a letter to Carl Friedrich Gauss seeking his advice about how to make data collection more efficient on the Magnetic Crusade, a large-scale initiative to study the earth's magnetic field. Surprisingly, even though Gauss had managed a similar initiative, he refused to give Herschel the advice he wanted, claiming that he needed to see Herschel's results before he could reply. Taking this miscommunication as a point of departure, this article traces the (...) cause of this miscommunication to differences in how each scientist viewed scientific training and the communicability of different kinds of scientific knowledge. (shrink)

While historians of the microscope currently consider that no programme of microscopy took place during the Enlightenment, the thesis challenges this view and aims at showing when and where microscopes were used as research tools. The focus of the inquiry is the research on microscopic animalcules and the relationship of European microscope making and practices of microscopy with topical trends of the industrial revolution, such as quantification. Three waves of research are characterised for the research on animalcules in the Enlightenment: (...) 1. seventeenth-century observations on animalcules crowned by Louis Joblot's 1718 works in the milieu of Paris Académie royale des sciences, 2. mid eighteenth-century observations and experiments on polyps and animalcules (Trembley, Baker and Hill) and, 3. between 1760 and 1790, OF Müller's establishment of the systematics of infusoria in Denmark and Germany. (shrink)