“The 'Subtile Aereal Spirit of Fountains': Mineral Waters and the History of Pneumatic Chemistry”

Leslie Tomory (McGill University)

In the early 1740s, the British physician and natural philosopher William Brownrigg (1711–1800) advanced a robust pneumatic theory claiming the existence of various kinds of “airs,” each with its own proper chemical characteristics. The atmosphere accordingly consisted of a mixture of different fluids that shared the characteristic of permanent elasticity. When evaluated against the standard story of the rise of pneumatic chemistry and its role in the Chemical Revolution, the timing of these ideas is outstanding, implying that later elaborations of the multiplicity of airs or the view of air as a third state of matter should be seen as the products of a longer and much more continuous history than previously recognized. The talk focuses on a central thread that contributed to such mid-century claims about the nature of airs: the analysis of mineral waters, especially in the late seventeenth and early eighteenth centuries, in particular regard to what was variously referred to as the airs, exhalations, vapors, or spirits they HSS 2017 Session Proposal contained. Prominent natural philosophers, physicians, and chymists like Van Helmont, Robert Boyle, Johan Joachim Becher, Friedrich Hoffmann, Gabriel François Venel and others are shown to have diversely but increasingly considered the presence of an aerial component in mineral waters (or “aerial spirit,” to use Brownrigg’s phrase). Guided by differing motivations and modes of theoretical and practical reasoning, yet drawing on each other’s contributions, an informal community of pneumatic practitioners negotiated the physical, medical, and especially chymical dimensions of such aerial components in mineral waters.

“Fluidity, Elasticity, and Activity: Chemical and Physical Airs from Robert Boyle to Stephen Hales”

Victor Boantza (University of Minnesota)

The notion of a “permanently elastic fluid,” which by the late eighteenth century was commonly used by pneumatic practitioners like James Keir, Tiberius Cavallo, and others, encapsulates key aspects of the history of air, as it gradually turned into a chemical species and a physical state of matter. The talk examines the evolution of early conceptions of Air in terms of elasticity, permanent fluidity, and material activity. The analysis showcases the interplay between theory and practice from early investigations of Air’s mechanical properties, through Boyle’s employment of the notion of “springiness” or elasticity, to the rise to prominence of various concepts of fluids, including aerial fluids, based on the work of Boyle, Newton, and their contemporaries. By mobilizing new accounts of ‘elastic fluids’ in the early 1700s pneumatic practitioners offered explanations based on analogies between Air and Fire. By the 1720s–30s, in the aftermath of Hales’s demonstration that air could be fixed in and obtained from solid and liquid substances, natural philosophers, physicians, and chemists introduced further distinctions between atmospheric Air and conceptions of air as an active material agent and a form of matter. By the middle of the century, increasingly prevalent references to permanently elastic fluids epitomized the culmination of these developments. This reading complements and complicates the received narrative of the rise of pneumatic chemistry as essentially driven by a chain of landmark experiments facilitated by technological innovations ranging from the air-pump to the pneumatic trough.

“Corrupted Bodies and Airs: The Problem of Putrefaction in Enlightenment Europe”

Margaret Carlyle (University of Minnesota)

Diderot and d’Alembert’s Encyclopédie defined chemical putrefaction as the final stage of fermentation, or the moment of a corrupting body’s ultimate dissolution. The German chemist-physician Georg Ernst Stahl viewed putrefaction as the last state of material division in which ‘mixts’ still conserved their integrity while approaching most closely elementary status. Informed by such notions, eighteenth-century practitioners addressed the problem from a variety of chemical, medical, and natural historical perspectives, considering its preponderance in the animal, vegetable, and mineral realms. This paper reconstructs the efforts of an unofficial network of pneumatic experimenters to understand and control this mysterious phenomenon, empirically related to Air and heat. Their work is traced on both sides of the Channel, from influential publications to local reports and from purpose-built laboratories to makeshift workshops set up along military battlefields. Based on his study of army men who had succumbed to infectious diseases like necrosis of the flesh and scurvy, Scottish physician John Pringle published in the 1750s his chemico-medical account of putrefaction. Pierre-Joseph Macquer, a prominent French Stahlian, encouraged his pupil Mme Thiroux d’Arconville to further pursue this problem, attributed to a “septic principle.” Her association of antiseptic capacities with substances’ protective power against the corrupting influences of outside Air complemented the work of Irish surgeon David MacBride in the 1760s. The latter advanced the promise of “fixed air” as part of a unique medical matter theory that was subsequently developed in the contributions to the 1767 prize contest on the subject at the Dijon Academy.

“Pneumatic Chemistry in the Making: The Writings of James Keir and Pierre-Joseph Macquer, 1766–1779”

Kristen Schranz (University of Toronto)

Most widely acknowledged eighteenth-century pneumatic ‘developments’ appear to prepare the way for the Chemical Revolution by French chemists in the late 1780s. Yet the making and circulating of pneumatic knowledge was often untidy and convoluted, rendering a linear progression of knowledge from Boyle to Lavoisier via various British chemists incomplete and untenable. The 1770s was a pivotal decade for pneumatic chemistry as natural philosophers, physicians, manufacturers, and civil servants on the Continent and in Britain attempted to capture, study, and validate pneumatic productions despite a lack of consensus about the nature of air(s) and the absence of a universal terminology to describe apparatus and observations. In order to understand the nuances and difficulties of pneumatic knowledge ‘as it happened’ in the 1770s we need to look beyond the iconic figures in the traditional narrative. The Scottish-born manufacturer James Keir and the French physician and lecturer Pierre-Joseph Macquer played an important role in summarizing, annotating, translating, and circulating chemical knowledge in this era. By tracing iterations of concepts, experiments, and theories in their published texts, the talk shows how Keir and Macquer represented the growing interface of pneumatic discussions between Britain and France. An examination of Macquer’s and Keir’s contributions and treatises on air(s) throughout the 1770s confirms the rapidly changing dynamics in pneumatic chemistry to show its dependence on prompt knowledge sharing via dictionaries, letters, translations, private notes, experiments, as well as networks of personal and institutional connections.