This paper investigates the Chinese American Chemical Society (CACS) as an organisation of the scientific diaspora at the end of the Cold War. Established in 1981 by mostly first-generation immigrants, the CACS adopted a non-political stance to boost the career of its members in the United States, China, and Taiwan. Tracing this non-political sensitivity to its founder, Jesse Hwa (1924-2008), the paper begins with Hwa's career as an immigrant scientist and his experience with China at the beginning of its economic reforms of the 1970s. It then studies the CACS's ambition to overcome the Cold War divide in the 1980s and reach out to Taiwan and China simultaneously. However, with limited success in technology transfer and facing issues in expanding the membership, the CACS faced a further crisis in the June Fourth Incident of 1989. As the officers tried to maintain the non-political stance amid varying responses from its members, the CACS increasingly turned attention to forging an identity for Chinese American chemists. By analysing the strategies of the CACS in building a community within the scientific diaspora, the paper enriches current scholarship on the history of twentieth-century chemistry and science diplomacy during the final days of the Cold War.

The article studies the strategies that late-medieval scribes used to present alchemical texts to their audience. Investigating two late fifteenth-century alchemical codices - Trinity College, Cambridge, MSS O.5.31 and R.14.37, both almost exclusively written in English - we demonstrate that the copyists took considerable pains to present reader-friendly texts. They provided neatly separated textual units, furnishing them with headings, manicules (pointing hands), and even a table of contents. This organisation is supported by the use of various ink colours, letter sizes, and framing devices. The appearance suggests significant pre-planning, perhaps even in a commercial context. We argue that these manuscripts highlight how readers engaged with alchemical texts and, by extension, that they reveal the importance afforded to texts and the vernacular as a vehicle for disseminating alchemical knowledge. In other words, it is not only the number of surviving manuscripts and their alchemical contents that are good indicators of late-medieval valuations of alchemy. Our study underscores how the visual materiality of extant textual artefacts also constitutes crucial evidence for our understanding of how practitioners used alchemical texts. It also exposes the place of alchemical texts in the text production industry of the time and illustrates the status of fifteenth-century alchemy more widely.

This paper considers the circumstances of an article written by John Davy, brother of Sir Humphry Davy, in which he presented the first chemical analysis of snakestones. Davy encountered snakestones in Ceylon (Sri Lanka), where he was posted as a medical officer of the British army in the early nineteenth century. The equipment that Davy took to Ceylon demonstrated his intent to find and analyse unfamiliar local materials, thus carrying out a dual role as a "surgeon-naturalist." By comparing Davy's original notes on snakestones with his final published work, aspects of Davy's personality, and parallels between Davy's notetaking style and that of his brother, come to light. Davy's chemical analysis of snakestones was ground-breaking in the history of this purported alexipharmic. However, the significance of his publication was largely undercut by dismissive remarks contained in a note, "Additional Observations, by the Secretary," appended to its publication.

This paper revisits the very well-known episode of Humphry Davy's electrical detection, isolation, naming, announcement, and publication of potassium and sodium. His initial experiments were made in the basement laboratory of the Royal Institution during the autumn of 1807. This paper draws on recently digitised Davy manuscripts as well as two letters (published as an appendix) written by the medical student Henry Holland to his father at the end of November 1807 which all provide significant new insights into this episode. The letters also illustrate the sociability and clubbable mores of the scientific and medical communities. Taken together these sources tell a complex story of the issues involved surrounding Davy's results, what the nature of the new substances were and what they should be named (the evolution of their names has not been previously discussed) and, perhaps, most strikingly, how the new metals might be interpreted in terms of phlogiston theory. But beyond that, I interpret Davy's discovery of potassium and sodium as part of a long continuum of his approach to chemical and geological research and theory, rather than, as most of the historical literature portrays, an isolated but important event.

In the present article, I analyse a text attributed to a Byzantine alchemist, the so-called Christian Philosopher or Christianos. I argue that within this text it is possible to find one of the earliest descriptions, in the Mediterranean world, of lac dye and shellac manufacturing. The text is also useful for establishing a more precise chronology within the debate concerning the date of Christianos, placing him in the early seventh century CE, during the reign of the emperor Heraclius.

In 1909, Friedrich Rathgen, chief chemist of the Berlin Museums, faced a challenging task: dating a bust and ideally confirming its origin as a Renaissance artwork attributed to Leonardo da Vinci. To authenticate the bust, the chemical composition of its wax components had to be determined, forming historical arguments for the dating of the object by correlating the material components with their historical usage. Debates arose among fat chemists about accurate techniques and the complexities of isolating substances from historical wax. This case illustrates the relationship between art history and chemistry in the analysis of material objects. It shows how chemists adapted their methods to address the challenges of the scientific analysis of art works and how historical and chemical hypotheses intertwined to form art historical arguments. Moreover, it highlights the reciprocal benefits derived from chemistry's engagement in art history, thereby advancing methods in both disciplines. Tracing the origins of fat chemistry within the broader context of chemistry and contextualising the museum's chemical laboratory within art history, this study draws attention to the larger context encompassing both natural sciences and humanities. Lastly, this study serves an instructive example of the transfer of practical knowledge between sciences and humanities around 1900.

This paper explores the philosophical and practical implications of the natural versus synthetic distinction in chemistry. I consider several interpretations of the term natural as pertaining to substances, and conclude that at its core, naturalness is best understood as a statement about material origin. The analysis reveals that calling a chemical substance natural risks committing a category mistake. The descriptor can only be coherently applied to samples of a chemical substance, not to a chemical substance as a set. Even in the case of samples, the utility of the term is limited. Care must be taken to avoid unwarranted implications.

This paper explores the intricate relationship between naturalness and bioplastics by examining celluloid, the first commercially successful (bio)plastic. By analysing the trajectory of celluloid, we can gain valuable insights into bioplastic design. Invented in 1868, celluloid transformed the consumer landscape by providing cost-effective alternatives to ivory. John Wesley Hyatt, the inventor of celluloid, developed innovative design and marketing strategies to navigate the public's perception of naturalness. In the context of billiard balls, celluloid's marketing strategy did not focus on its similarity to ivory but on its superior functionality. However, celluloid capitalised on its ability to mimic ivory's aesthetic qualities for everyday items like combs and fans. This paper argues that bioplastics may benefit from embracing their artificial qualities while gradually establishing the notion of their inherent naturalness over time.

The beauty line, exemplifies the ambivalent construction of naturalness surrounding an early cosmeceutical product in 1970s West Germany. This line of skincare products, featuring biologically active ingredients, was marketed as a preventative solution for skin ageing, revealing tensions between societal perceptions of ageing and the ideal of the "natural look" in the context of a polluted environment. presence in pharmacies, drugstores, and health food stores illustrates its role in blurring the lines between cosmetics, pharmaceuticals, and natural products, reflecting Ilana Löwy's "boundary concepts." Drawing on the archival resources on of Bayer Archives Leverkusen, this article examines how nature is simultaneously portrayed as both a hero and an adversary in the quest for the "natural look," revealing the complexities inherent in the cosmetic industry's construction of naturalness.

When the birth control pill was introduced at the beginning of the 1960s, it was primarily used to regulate women's menstrual cycles. Medical historians have argued that such a naturalised menstrual cycle did not exist until hormonal products were used to regulate it. Menstrual irregularities had been the go-to indication for hormonal products, long before hormones were specifically produced for contraceptive purposes. This paper traces the concurrent development of the notion of a "natural cycle" and respective marketing strategies to promote Sequilar, the first sequential birth control pill by Schering AG in 1974. Drawing upon archival resources in the Schering AG Archive, Berlin, the paper examines the notion of producing a "natural cycle." The paper utilises internal documents, letters to doctors, brochures, and prescription guidelines. It argues that the intention of producing a "natural cycle" through hormones led to a naturalisation of menstrual cyclicity and rhythm, while also normalising side effects as part of menstruation.

Naturalness is a highly discussed and controversial term. Not only are there several definitions of naturalness, but what is perceived as can vary among social groups and individuals. Even though the understanding of the term is not as straightforward as one might assume, it is commonly used. To untangle the various perspectives and understandings of naturalness, this article studies the evolution of the regulations for the labelling of flavourings in food in Germany from 1959 to the early twenty-first century. Analysing three decrees regulating the declaration of natural and non-natural flavours, this article puts forward strategies for reframing non-natural substances and the construction of naturalness.

In medieval Latin alchemy, "the work" () in the laboratory paralleled the work of nature - yet while nature took over "a thousand years" in the mine, the artifex in the laboratory would only need "a month, or a shorter, or longer time." The amount of time needed was dependent on the degree of heat of the fire. A higher degree of heat () would speed up the process, while baking the given preparation over a slow, gentle fire () prolonged it. This paper argues that for medieval Latin alchemists, the accomplishment of the magisterium depended on finding the precise moment to take away the product from the fire, by regulating the intensity of fire and observing natural signs. While ancient alchemy saw success linked to an astrological "favourable moment" chosen for the of the work, medieval Latin alchemy brings a more naturalistic focus on figuring out what I call the "Goldilocks moment": the exact moment of ripeness at the end of the work, beyond which the action of fire would naturally become destructive. The paper examines this practical philosophy of fire and its relationship with time in material transformation in Petrus Bonus' .

In this article we reflect on the reconstruction and operation of a lung-powered, portable melting furnace used by ancient Amerindian goldsmiths. Variations of this kind of furnace were operated by different metallurgical traditions in the northern Andes and Mesoamerica to transform refined metals and alloys like (copper and gold) into metalworks such as ornamental artefacts. The social and technological shifts that began in the sixteenth century, particularly following European contact, led to a progressive decline of the ancient Amerindian melting procedures associated with these metallurgical furnaces. Our research utilises performative and reconstructive methods to offer a reparative approach to this lost fire-and-wind technology, taking the Quimbaya furnace as a working model. By assessing the historical and archaeological evidence as well as more intangible experiential insights from our reconstruction, we intend to understand the functioning of such furnaces, and to suggest embodied and social meanings of the arts of fire among ancient communities in the tropical valleys of the Andes.

This paper describes a programme of practice research that combines historical technology (small charcoal-fired furnaces) with contemporary digital making methodologies (digital CNC milling). The intention was to create small spherical granules of precious metal suitable for granulation, an ancient metalworking technique. The authors begin by providing an overview of granulation's historical background and the different traditional methods used to create granules. They give an account of the equipment used in the physical experiments and describe the rationale behind specific design decisions. In particular, they reflect on the nature and properties of producing a reducing atmosphere inside the firing chamber of the furnace, and the relevance of this to the granulation process. They detail the digital making methodologies that were used to create setters made from graphite to encourage the formation of perfectly spherical granules, and how these relate to recent developments of the technique by contemporary makers. The project is a case study that demonstrates how practical reflexive experimentation can broaden our understanding of unrecorded but crucial skills such as fire management and that practising such skills in conjunction with digital methods of making can offer new insights into past technologies and processes.

This article describes a programme of experimental reconstruction, involving the building and firing of a series of charcoal-fired assay furnaces, and the findings generated by this activity. The furnace builds drew from designs described and illustrated in nineteenth-century technical manuals for assayers and two sixteenth-century texts: by Georgius Agricola and by Lazarus Ercker. Comparing the resulting "chimeric" structures' performance generated insights into how such solid-fuel assay furnaces behaved in practice, what roles specific structural elements described in different primary sources played in their overall function, and the fire management skills needed to operate them. Consequently, it was possible to identify how the designs materialised technological choices that prioritised either responsiveness or long-term operation. The experimental reconstructions also led to a reappraisal of the nature and wider relevance of a selection of the primary sources used in the project.

In the study of early modern glassmaking, scholarship has traditionally focused on the production of raw glass and the transmission of glassmaking recipes and knowledge. This article extends that focus by examining the subsequent transformation of raw glass into finished objects, using enamelling as a central case study. We argue that enamelling was a distinct, skill-intensive practice requiring specialised knowledge separate from that of glass production. Combining historical source analysis with experimental reconstructions, the study investigates how fire management critically influenced enamel quality. By applying a range of firing techniques to reconstructed seventeenth- and eighteenth-century enamels, we demonstrate that variability in heat application significantly affected the final outcome. Our experiments suggest that historical enamellers developed a deep, practice-based understanding of several key factors: (i) controlling heat for optimal adhesion and colour development; (ii) manipulating flame intensity and furnace atmosphere to enhance bonding; and (iii) employing layering techniques to improve durability. These findings invite a rethinking of fire not merely as a tool, but as an active and variable ingredient in the enamelling process.

Starting from the insights gathered during the reconstruction of a small distillation furnace at the Fire Arts workshop, this paper begins to recover the significance of "low-heat technologies" in the early modern period. It asks how these were achieved technically and codified in the emerging practical literature, but also what was at stake theoretically - how did such low-heat technologies function within larger cosmologies and theories of matter? The works of Girolamo Cardano make for a pertinent case study since Cardano denied that fire was an element. Consequently, he placed fairly restrictive boundaries on its agency in manipulating matter, and especially in achieving his key material quality of "subtlety." At a second glance, however, I argue that Cardano makes remarkable exceptions for low-heat distillation as a technology that replicates Nature's most subtle material processes.

The introduction to this double special issue lays out our core questions: how was fire understood within premodern cultures of knowledge and practice? What could fire do, and what could humans do with fire? The introduction details our hands-on exploration of these issues through a range of fire technologies at an interdisciplinary workshop on "Fire Arts, Pasts and Futures" at Texas A&M University. It outlines the issues and new questions raised by this practical work, and shows how these are addressed in the contributions to this issue. These case studies explore the practices of premodern artisans, alchemists, metalworkers, natural philosophers, and chemical practitioners, ranging from low-heat technologies such as distillation to high-heat smelting furnaces, and from ancient metallurgy to modern-day jewellery practice. Collectively, we argue, the articles contribute to three main areas of historical scholarship: the place of fire in changing cosmologies and matter theories, debates about the agencies of art vs. nature, and methodological reflections on using performative methods as part of an interdisciplinary exploration of past material worlds.

While fire played an obvious role in the work of early modern European metalworkers, glassworkers, earthenware potters, and other "high-heat artisans," this article examines how "low-heat artisans" engaged with fire in their workshop practice. It focuses on painters, bleachers, launderers, and dyers, and it looks for traces of their fire-related practices in manuscript and printed how-to texts, particularly craft manuals and books of artisanal recipes and secrets. By examining not only the various fire technologies and tools these artisans used but what they could do with fire, this article shows what we gain when we read for procedural and performative language rather than merely people, places, and concrete things. This study concludes that the use of low-heat fire among artisans was extensive and subtly varied; there are reasons to consider the sun a critical low-heat fire technology; and light, as a byproduct of fire, was just as carefully exploited or mitigated in low-heat artisanal work as was heat.

When Rudolph Glauber (1604-1670) announced a new chymical furnace in the late 1640s, he emphasised its ability to reach very high temperatures - without the aid of bellows - thanks to a cleverly engineered structure. This pyrotechnically innovative furnace marks a clear shift in early modern furnace design. In this article, we argue that Glauber's furnace was more than an isolated technological advance. Rather, his structural approach to furnace design emerged from a complex history of heat engineering, pressures of fuel scarcity, and ideas about the circulation of wind, air, heat, and smoke. By looking at his apparatus alongside pyrotechnical developments in the domestic sphere, we argue that the furnace was never merely a fire in a box, but rather forms an assemblage with the surrounding architecture and beyond. This broader view of the furnace allows us to further probe and historicise the early modern and to reassess the role of chymistry within it.

The goddesses of metal and fire were the patron deities of Chinese smelters. This article examines this artisans' cult through historical texts, ethnographic reports, and historical reconstruction of the smelting processes. It demonstrates that the cult was initially tied to the state-managed iron industry under Mongol rule (1271-1368), and later spread across geographical regions, encompassing diverse fire-related industries, including casting, bell making, tin smelting, and pottery. I argue that the cult constituted an integral part of artisans' material imaginary - a worldview that helped them comprehend the material transformation through fire, their bodily experience of extreme heat and danger, and the anxieties that were inherent to fire-related crafts. However, this widespread religious practice appears differently in historical texts, where Confucian scholars and state officials reframed the narratives about the goddesses, contributing to the cult's gradual disappearance in textual records. This study emphasises the limitations of conventional historical sources and advocates for combining historical reconstruction and folklore with archival research to recover marginalised forms of artisanal knowledge. Moreover, it argues that artisans' religious practices should not be separated from technological processes but rather treated as important components of artisanal knowledge systems.