Chemistry

CHEMISTRY

CHEMISTRY. The history of early modern chemistry, understood as a body of ideas and practices related to compounding and decomposing material substances, takes us to alchemy and apothecary laboratories, artisans' workshops, metallurgists and manufacturers, scientific societies, arsenals, royal courts, and public squares. It should not be understood in terms of the victory of scientific theory over arcane beliefs, but of the changing employment of its various technologies and the contexts in and by which they were legitimized.

MATERIAL AND BODILY TECHNOLOGY

Chemistry's material technology—that is, its instruments and laboratory equipment—remained stable throughout most of the period, but was augmented by precision-oriented apparatus in the second half of the eighteenth century as the study of heat and gases, along with early industrial innovations, redirected chemical investigations. Increasingly accurate measuring devices helped bring about standardization in manufacturing ventures (e.g. Josiah Wedgwood's pottery works) while feeding debates over how to organize chemistry as an investigative enterprise. Should the heterogeneous chemical world be disciplined by analyzing qualitative or quantitative data?

The way chemical operators and investigators used their own bodies was part of this historical development and debate. As long as chemical determination rested on examining colors, smells, tastes and textures, the human senses served as crucial chemical instruments. As experimental claims increasingly relied on precise measurements by the late eighteenth century (a hallmark of the chemical revolution), sense evidence became "subjective" and, hence, a questionable foundation for proof. Chemists continued to rely on their senses, but proof became increasingly a matter of quantitative determination.

THEORY AND PRACTICE

The question of what constituted a primary chemical element was not a part of practical chemists' daily routine. Neither, prior to the late eighteenth century, was there a direct correlation between one's theoretical views and how one actually carried out chemical procedures, which can be seen by examining the impact of the mechanical philosophy on chemistry. Textbook writers such as Nicolas Lémery (1645–1715) attributed a substance's qualities to the shape of particles that composed it. But authors left such explanations behind when dealing with actual chemical operations. Robert Boyle (1627–1691), often labeled a mechanical philosopher, made a bigger impact on chemistry through his interests in practical knowledge and alchemy. Even Isaac Newton's (1642–1727) mechanism, which married particles to short-range forces, hardly touched chemical practice—although theorists such as Georges-Louis Leclerc de Buffon (1707–1788) hoped chemical attraction (affinities) could be explained mathematically with Newtonian forces. Working chemists continued to learn their trade through apprenticeship and to be guided by practical recipes. Acquiring tacit knowledge and practical skills, then, were certainly as important for the historical development of chemistry as theoretical knowledge.

It is, however, historically important that matter theory became linked to chemical research in an increasingly instrumental way by the eighteenth century. Paracelsus (1493–1541), who argued for the chemical foundation of medicine (iatrochemistry), claimed that Aristotle's four elements appeared in bodies as mercury, sulfur, and salt. Mercury was the principle of volatility and fusibility, sulfur of inflammability, and salt of incombustibility. Therefore, chemists might recognize a compound not only as heavy or wet, but also as liable to specific chemical processes.

Johann Joachim Becher (1635–1682) substituted three categories of earth for Paracelsus's principles and explained material change largely in terms of their combination with and release from compounds through processes such as combustion. His student George Ernst Stahl (1660–1734) further codified Becher's work, giving the name "phlogiston" (from the Greek verb "to inflame") to Becher's terra pinguis (the sulfur of inflammability) and teaching that phlogiston's presence was responsible for characteristics including metallicity, color, and inflammability. In France, the influential chemistry lecturer Guillaume François Rouelle (1703–1770) popularized the idea of phlogiston, associating it with fire. Others such as Joseph Priestley (1733–1804) identified it variously with electricity and hydrogen. Phlogiston was used to explain phenomena including combustion, calcination, and the quality of air, thereby organizing a number of research activities under a set of interconnecting theories and emphasizing the potential reversibility of chemical processes.

Others began considering the Aristotelian elements as material instruments. Stephen Hales (1677–1761) focused on the expansion of air and the way in which it could become "fixed" in bodies. Herman Boerhaave (1668–1738) went further, organizing his chemistry lectures largely around the investigative consequences of considering earth, water, air, and fire as instruments that afforded specific chemical processes. A Newtonian by public pronouncement, Boerhaave actually did much more to stimulate chemical research by focusing on the reactive effects of these elemental instruments. He related fire (the substance of heat) to the primary processes of expansion and repulsion. He presented air and water as providing containers in which other particles were suspended. It wasn't long before these "instruments" themselves were subjected to chemical analysis, as investigators sought to understand whether their "instrumental" presence was chemically passive or active. Research in the second half of the eighteenth century was marked by investigations of newly discovered gases (qualitatively distinct "airs"), the role of heat, and, in the 1780s, the composition of water.

LITERARY TECHNOLOGY

Chemical theory and instrumental research practices were also linked in the way chemical knowledge came to be organized nomenclaturally and in analytical tables (chemistry's literary technology). Related to the heritage of alchemy and the various contexts in which chemical substances were discovered and used, chemical nomenclature was traditionally a colorfully unsystematic affair. Growing interest in chemical research in the second half of the eighteenth century, especially the investigation of a number of new "airs," led chemists to consider nomenclatural reform. Standard conventions for naming new substances would allow researchers from various communities to communicate. In 1787 Antoine Laurent Lavoisier (1743–1794), Louis Bernard Guyton de Morveau (1737–1816), Antoine François Fourcroy (1755–1809), and Claude Simon Berthollet (1748–1822) revamped chemistry's nomenclature totally, enunciating in their Méthode de nomenclature chimique a revolutionary way to structure chemistry's investigative knowledge and practices.

Oxygen's discovery and naming provides a good example. Recognized in the 1770s as a distinct "air" responsible for combustion, supporting respiration, and the process of calcination, it was variously named the "purest part of air," "fire air," "eminently respirable air," and "dephlogisticated air." Lavoisier focused on what he considered its most far-reaching characteristic and argued that it should be called "oxygen," the "generator" of acids. Not only did he use oxygen's causal properties to argue against the existence of phlogiston, he named the substance in a way that simultaneously reflected how the relation between these properties ought to be understood and how chemists ought to pursue future research.

Traditionally, the secretive nature of many alchemical and artisanal practices had combined with chemistry's lack of institutional and disciplinary unity to work against the development of a public, systematic means of recording compositional data. This began changing when Étienne François Geoffroy (1672–1731) presented his "Table of the different relationships observed between different substances" to the French Academy of Sciences in 1718. Recording and publishing these relationships, often called affinities, provided a handy way for chemists to share and expand empirical knowledge without having to agree on their theoretical explanation. As the century progressed, affinity and solvent tables became more sophisticated (recording, for example, how relations were observed), leading chemists to hope that their field might thereby gain the certainty of a scientific discipline. As was true with nomenclatural reform, this was largely achieved by Lavoisier and his colleagues, with revolutionary results. Lavoisier's 1789 textbook Traitéélémentaire de chimie included tables whose structures redirected research along the same lines as chemistry's new nomenclature.

Lavoisier began his textbook by arguing that humans live in a Condillacian world; chemists should therefore build their discipline on a foundation of sensible facts. Chemistry's nomenclature should express only what chemists actively observed; its basic elements should be defined by laboratory procedures. In fact, Lavoisier began his "table of simple substances" with five elements that could never be isolated, but which he made responsible for fundamental chemical processes. Oxygen "generates" acidity, hydrogen "generates" water. Caloric, the substance of heat, interacts with chemical affinities to regulate composition and decomposition. In place of affinity and solvent tables, Lavoisier filled his textbook with tables that simultaneously recorded and predicted the combinatorial powers of elements such as oxygen. Together they formed an integrated research program intended to discipline chemistry.

CHEMISTRY'S INSTRUMENTALIZATION

Lavoisier's laboratory practices reflected what appeared on the pages of his book, the last third of which treated laboratory instruments. If primary elements couldn't be isolated, Lavoisier argued that their active presence could be quantitatively traced. Unmeasurable phlogiston was out, precision balances were in, as seen in his proof that water is compounded of hydrogen and oxygen. Affinities could not yet be quantified, but the effect of caloric on composition and decomposition could be quantitatively inferred by the melting of ice in an ice calorimeter—an instrument designed by Lavoisier. In general, nomenclature, instrumental theory, and measurement provided a research program for future chemists, in terms of both questions and methods for resolving them.

This culmination of chemistry's instrumentalization was, arguably, the essence of the chemical revolution. Whether others adopted Lavoisier's theories or followed the specifics of his research proposals, the modern discipline of chemistry was permanently marked by the instrumental bounds he prescibed.

See also Alchemy ; Apothecaries ; Boerhaave, Herman ; Boyle, Robert ; Lavoisier, Antoine ; Paracelsus ; Priestley, Joseph .

BIBLIOGRAPHY

Bensaude-Vincent, Bernadette. Lavoisier. Memoires d'une révolution. Paris, 1993.

Golinski, Jan. Science as Public Culture: Chemistry and Enlightenment in Britain 1760–1820. Cambridge, U.K., 1992.

Hannaway, Owen. The Chemist and the Word: The Didactic Origins of Chemistry. Baltimore, 1985.

Holmes, Frederick Lawrence. Eighteenth-Century Chemistry as an Investigative Enterprise. Berkeley, 1989.

Roberts, Lissa. "The Death of the Sensuous Chemist: the 'New' Chemistry and the Transformation of Sensuous Technology." Studies in History and Philosophy of Science 26 (1995): 503–529.

——. "Setting the Table: The Disciplinary Development of Eighteenth-Century Chemistry as Read through the Changing Structure of its Tables." In The Literary Structure of Scientific Argument, edited by Peter Dear, pp. 99–132. Philadelphia, 1991.

Lissa Roberts