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 article attempts a contextual study of the origin and early development of August Kekulé's theory of aromatic compounds. The terminus a quo is essentially August Hofmann's coining of the modern chemical denotation of ‘aromatic’ in 1855; the terminus ad quem is the first full codification of Kekulé's theory in the sixth fascicle of his Lehrbuch der organischen Chemie, published in the summer of 1866. Kekulé's theory is viewed in context with the earlier and concurrent experimental work of such chemists (...) as Hermann Kolbe, Friedrich Beilstein, Rudolph Fittig, and Hugo Müller. The reception of the theory is briefly examined. Attention is paid to the role of Kekulé's molecular models and of his celebrated dream anecdote of the snake that seizes its own tail. The episode is used as a case study for the continuity of scientific progress, and to illustrate the close reciprocal interactions of hypothesis and experiment in the evolution of a scientific theory. (shrink)

Some recent philosophers of science have argued that chemistry in the nineteenth century “largely lacked theoretical foundations, and showed little progress in supplying such foundations” until around 1900, or even later. In particular, nineteenth-century atomic theory, it is said, “played no useful part” in the crowning achievement of nineteenth-century chemistry, the powerful subdiscipline of organic chemistry. This paper offers a contrary view. The idea that chemistry only gained useful theoretical foundations when it began to merge with physics, it will be (...) argued, is based on an implicit conception of scientific theory that is too narrow, and too exclusively oriented to the science of physics. A broader understanding of scientific theory, and one that is more appropriate to the science of chemistry, reveals the essential part that theory played in the development of chemistry in the nineteenth century. It also offers implications for our understanding of the nature of chemical theory today. (shrink)

This essay describes the complexities, challenges, and pleasures of translating from German into English a charming fantasy about the world of molecules, published in 1882 by the chemist and historian Hermann Kopp (1817–1892).

Professor Needham tells me that I have misunderstood him, and I am sure he is right that I need to work harder to understand his arguments more fully and more precisely. But he has also misunderstood me, as well—no doubt because I have not expressed myself as carefully as I ought to have done. He writes that I have “clearly” argued that “the only possibility of representing nineteenth-century chemistry as a theoretical pursuit” is based on chemical atomism. I do not (...) believe that. For instance, Lavoisien antiphlogistic theory at the beginning of the century, and chemical thermodynamics and certain aspects of reaction dynamics a few decades later, did not depend on an atomistic view of nature.I do plead guilty to the claim that “at the heart of the theoretical achievement” of nineteenth-century chemistry stood “atomic and molecular theory”. But Professor Needham believes that nineteenth-century atomism did not provide chemistry with any explanations. Since I take it that a principal goal .. (shrink)