Most contemporary chemists consider quantum mechanics to be the foundational theory of their discipline, although few of the calculations that a strict reduction would seem to require have ever been produced. In this essay I discuss contemporary algebraic and diagrammatic representations of molecular systems derived from quantum mechanical models, specifically configuration interaction wavefunctions for ab initio calculations and molecular orbital energy diagrams. My aim is to suggest that recent dissatisfaction with reductive accounts of chemical theory may stem from both the (...) inability of standard accounts of reduction to incorporate the diverse forms of representation found in chemical practice and our philosophical predilection to analyze all connections between theories in terms of logical reduction. (shrink)

Mendeleev’s failure to represent the periodic system as a continuum may have hidden from him the space for the noble gases. A spiral format might have revealed the significance of the wide gaps in atomic mass between his rows. Tables overemphasize the division of the sequence into ‘periods’ and blocks. Not only do spirals express the continuity; in addition they are more attractive visually. They also facilitate a new placing for hydrogen and the introduction of an ‘element of atomic number (...) zero’. (shrink)

This article focuses on the Russian chemist Dmitri Ivanovich Mendeleev's assessment of certain representations of various aspects of the periodic system that employed more mathematical methodology. The equations of interest were created by E. J. Mills, B. N. Chicherin, and J. H. Vincent. The English chemist Mills tried to find a firmer numerical basis for the periodicity of the elements. The Russian lawyer and political philosopher Chicherin was convinced of the existence of a mathematical law underlying the periodic system. The (...) English physicist Vincent explored the connection between atomic weights and the elements' order in listings based on atomic weights—a project which he associated with the periodic system of elements. Although, for Mendeleev, the equations of Mills, Chicherin, and Vincent promised a more precise expression of the law of periodicity, he continued to invoke his earlier standards. In particular, Mendeleev wanted the equations to respect the individuality of the elements, and called for completeness in conveying the complexities of chemical phenomena. Thus, the very qualities that he had valued while developing his periodic system in 1869–1871 also characterised his evaluation of the new means of representing aspects of that system. (shrink)

The epistolary exchanges of early modern natural history have long been of interest to historians of science, as they reflect the dynamic nature of the emergent discipline better than the printed volumes of natural history. Less attention, at least until recently, has been paid to the unfinished pieces, the cryptic marginalia, and the practical notes that more often than not accompanied letters. Lists of specimens sent or requested were among the new tools at the naturalist's disposal for dealing with a (...) scientific world increasingly populated by objects. This essay seeks to reconstruct the genealogy of specimen lists by focusing on little-known apothecaries in northern Italy: the individuals traditionally held to be social counterparts to these modest strings of words. It seems that the operations at the back of the shop and the literature generated by the centuries-old drug and spice trades may have been a more defining influence on early modern naturalists than the humanist practices of indexing and commonplacing that were concurrently embraced by Italian studiosi. (shrink)

Summary Colourful plant images are often taken as the icon of natural history illustration. However, so far, little attention has been paid to the question of how this beautiful colouring was achieved. At a case study of the eighteenth-century Nuremberg doctor and botanist, Christoph Jacob Trew, the process of how illustrations were hand-coloured, who was involved in this work, and how the colouring was supervised and evaluated is reconstructed, mostly based on Trew's correspondence with the engraver and publisher of his (...) books, Johann Jacob Haid in Augsburg. Furthermore, the question of standardizing colours, their uses and their recipes is discussed at two examples of the same time period: the colour charts of the Bauer brothers, arguably the most renowned botanical draughtsmen of the period, and the colour tables by the Regensburg naturalist, Jacob Christian Schaeffer. Hand-colouring botanical illustrations, it is argued, was far from a straightforward task but confronted botanists and their employees with a plethora of practical and methodological problems, to which different solutions were developed in the course of time. Analysing these problems and solutions reveals some new and interesting aspects of the practices of eighteenth-century botany and of the production of scientific illustrations in general. (shrink)

The Swedish naturalist Carl Linnaeus is famous for having turned botany into a systematic discipline, through his classification systems—most notably the sexual system—and his nomenclature. Throughout his life, Linnaeus experimented with various paper technologies designed to display information synoptically. The list took pride of place among these and is also the common element of more complex representations he produced, such as genera descriptions and his “natural system.” Taking clues from the anthropology of writing, this essay seeks to demonstrate that lists (...) can be considered as genuine research technologies. They possess a potential to generate research problems of their own but also pose limitations to inquiries that can be overcome only by the use of new media. (shrink)

This paper presents the contributions of Alcindo Flores Cabral, professor of Chemistry at the Faculdade de Agronomia Eliseu Maciel, nowadays part of the Universidade Federal de Pelotas, to chemistry teaching. It is a contribution almost unknown to the Brazilian chemical community, although recognized as valuable by several renowned chemists abroad, like W. Hückel, G. Charlot, F. Strong, E. Fessenden and others. Cabral’s innovative helical representation is presented in connection not only with contemporary representations, but also an incursion is made into (...) the first helical systems proposed, those of Hinrichs and of Baumhauer. Some comments are made not only on Cabral’s Classificação Natural dos Elementos, published in 1946, but also about other texts he wrote for an efficient chemistry teaching. (shrink)

Sociologists, philosophers and historians of science are gradually recognizing the importance of visual representation. This is part of a more general movement away from a theory-centric view of science and towards an interest in practical aspects of observation and experimentation. Rather than treating science as a matter of demonstrating the logical connection between theoretical and empirical statements, an increasing number of investigations are examining how scientists compose and use diagrams, graphs, photographs, micrographs, maps, charts, and related visual displays. This paper (...) focuses on diagrams in biology, and tries to demonstrate how diagrams are an integral part of the production of scientific knowledge. In order to disclose some of the distinctive practical and analytical uses of diagrams, the paper contrasts the way diagrams and photographs are used in biological texts. Both diagrams and photographs are shown to be “constructions” that separately and together mediate the investigation of scientific phenoman. (shrink)

This paper raises the question of the prominence and use of statistical graphs in science, and argues that their use in problem solving analysis can best be understood in an ‘interactionist’ frame of analysis, including bio-emotion, culture, social organization, and environment as elements. The frame contrasts both with philosophical realism and with social constructivism, which posit two variables and one way causal flows. We next posit basic differences between visual, verbal, and numerical media of perception and communication. Graphs are thus (...) seen as key interactive sites where different media are transformed into more interpretable forms. Examples are taken from Limnology where numbers are transformed into graphs to find patterns in them, and thus, by implication in the environmental materials from which the numerical measurements were taken. Their revisualization by passes a human cognitive limitation, for the direct analysis — interpretation of lists and tables of numbers, visual imaging being a cognitive strength. Sense of problem, conceptual repertoire, and social relations are seen to direct this pattern search and interpretive process. (shrink)

This paper studies the semiotic,epistemological and historical aspects of Berzelianformulas in early nineteenth-century organicchemistry. I argue that Berzelian formulas wereenormously productive `paper tools' for representingchemical reactions of organic substances, and forcreating different pathways of reactions. Moreover, myanalysis of Jean Dumas's application of Berzelianformulas to model the creation of chloral from alcoholand chlorine exemplifies the role played by chemicalformulas in conceptual development (the concept ofsubstitution). Studying the dialectic of chemists'collectively shared goals and tools, I argue thatpaper tools, like laboratory instruments, areresources (...) whose possibilities are not exhausted byscientists' attempts to achieve existing goals, butrather whose applications generate new goals. The term`paper tools' is introduced to emphasize that thepragmatic and syntactic aspects of symbol systems arefully comparable to physical laboratory tools. (shrink)

Today the economic diagram is employed universally in teaching and research by professional economists. Yet the history of its construction shows that much that has been regarded as distinctive of twentieth-century visual culture was prefigured in the nineteenth. This paper will place the construction of the first economic diagrams by Alfred Marshall in the context both of contemporary visual technologies developed in other moral sciences, and of his wider theory of industrial production. The paper will argue that an understanding of (...) the background to the historical graphs, constructed by the Cambridge political economist from the late 1860s onwards, will necessitate a revision of the narrative of modern visual reasoning, as recently advanced by Lev Manovich. (shrink)