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)

In the course of his chemical investigation of crude platina ore, William Hyde Wollaston in 1802 isolated and characterized the metal palladium. In early 1803, he chose to make known his discovery by offering small samples of the metal for sale through a small shop in London. In the notice advertising the properties of the new metal, no information was given as to its source nor to its discoverer. The unique properties of the metal, and the secrecy surrounding its discovery, (...) led the Irish chemist Richard Chenevix to question the elemental nature of the new metal. His hasty but extensive investigation of the chemical properties of palladium convinced him that it was no more than an alloy of platinum and mercury, and he denounced the discovery as fraudulent. The president of the Royal Society, Joseph Banks, was drawn into the resulting furore, and correspondence between him and Chenevix reveals involved plans to obtain the identity of the palladium discoverer. The controversy is viewed as a significant episode in the continuing debate in the chemical community over the operational definition of a chemical element, and although Chenevix's concern over the growth in the number of new elements was justified, his choice of palladium as a test case was an unfortunate one, for his claim that the metal was an alloy was found to be erroneous. Motives for the actions of both Chenevix and Wollaston are sought, and the judgement that their careers were damaged by the incident is questioned. (shrink)

SummaryJohn Dalton's atomic theory, with its postulate of compound formation through atom-to-atom combination, brought a new perspective to weight relationships in chemical reactions. A presumed one-to-one combination of atoms A and B to form a simple compound AB allowed Dalton to construct his first table of relative atomic weights from literature analyses of appropriate binary compounds. For such simple binary compounds, the atomic theory had little advantages over affinity theory as an explanation of fixed proportions by weight. For ternary compounds (...) of the form AB2, however, atomic theory made quantitative predictions that were not deducible from affinity theory. Atomic theory required that the weight of B in the compound AB2 be exactly twice that in the compound AB. Dalton, Thomas Thomson and William Hyde Wollaston all published within a few years of each other experimental data that claimed to give the predicted results with the required accuracy. There are nonetheless several experimental barriers to obtaining the desired integral multiple proportions. In this paper I will discuss replication experiments which demonstrate that only Wollaston's results are experimentally reliable. It is likely that such replicability explains why Wollaston's experiments were so influential. (shrink)

(1980). William Wollaston, John Johnson and Colombian alluvial platina: A study in restricted industrial enterprise. Annals of Science: Vol. 37, No. 3, pp. 253-268.