Abstract

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'.