This article examines the origins of the golden pigment known as mosaic gold (SnS), formed through the sublimation of tin with mercury, sulphur, and ammonium chloride. It explores the textual transmission of mosaic gold from the earliest known written testimonies, as well as the earliest material remnants of the pigment during the thirteenth and fourteenth centuries. Additionally, the study introduces and analyses two new recipes from an earlier date: one comes from the Greek treatise known as the ; and the other from the Latin alchemical work attributed to pseudo-Avicenna, . The analysis of these new recipes allows for a better understanding of the origin of the pigment and its connection with the medieval alchemical tradition inherited from the Arabic world. Based on these testimonies, the study proposes a new hypothesis about the origin, development, and etymology of mosaic gold.

Motivated by her interest in fabric arts, late-eighteenth-century British chemist Elizabeth Fulhame experimentally investigated whether cloths of gold, silver, and other metals could be made by chemical rather than mechanical processes. In contrast to other women studying science at this time, she not only published an original monograph under her own name that challenged both the phlogistic and antiphlogistic views of combustion but also proposed an alternative explanation for oxidation and reduction. Although her contemporaries widely cited her innovative research, her history is not well known, yet a careful analysis of her work provides further insights into the reception of the antiphlogistic theory and the challenges and limitations experienced by women in chemistry during this period.

The composition and way of production of Michael Maier's medicament Coelidonia, mentioned in his book were inferred from indications in Maier's book . The substance was synthesized by the author in a modern laboratory. It is a lead oxychloride of brilliant yellow colour with a composition of approximately PbOCl. The same substance was produced from the 1780s to at least 1825 as a pigment under the names of Patent Yellow, Turner's Yellow and Casseler Mineral-Gelb (Cassel Mineral Yellow).

This essay brings together research in the history of science and soft matter physics to consider how early modern Italian apothecaries organised and communicated their knowledge from the fourteenth to the seventeenth century through an "apothecary taxonomy." This was based on a what we call a "hylocentric" classification scheme (from the Greek  = matter, material, stuff) founded on a tactile understanding of materials. We will investigate how the behaviour of medicines under deformation and flow - their "rheology" - is a previously underestimated organisational principle, and consider the specialist vocabulary these author-practitioners used to describe different liquid and liquid-like formulations. We will also suggest that the rheology of these formulations - which today falls under the domain of "soft matter science" - affected the material culture of apothecary shops, in the arrangement and selection of drug bottles and jars, which presented this knowledge visually to visitors and clients. That soft matter scientists organise the substances they study in similar ways to early modern apothecaries suggests the agency of materials in affecting human categorisations.

The development of defect-free flint glass for use in telescopes and navigational instruments was a key technological challenge facing European chemists, natural philosophers, and artisans that emerged in the 1750s. In 1805, Pierre-Louis Guinand, a Swiss artisan, invented a fireclay stirrer used to stir molten flint glass to create a homogenous mixture relatively free of defects. In this paper, I show it was not Guinand, but French chemist Antoine Baumé, who first came up with the idea of using a fireclay stirrer. More important, both Guinand and another early optical glass researcher, Josiah Wedgwood, knew of and were influenced by Baumé's work. Baumé's optical glass contributions have been forgotten over the years for several reasons. First, he never promoted his idea of a fireclay stirrer due to the limited support and likelihood of failure for such an artisanal-focused project within the , which stressed theory over practice with regards to glassmaking. Second, glassmakers were hesitant to reveal their trade secrets and sources. And third, until fairly recently, Baumé's unrelenting support of the phlogiston theory led to his relegation as a minor figure in the history of chemistry, and his optical glass ideas fell off the radar of subsequent historians.

This article focuses on a curious manuscript treatise in the British Library, Harley MS 6940, which the learned physician Samuel Bispham composed for the English patron and horseman William Cavendish (1593-1676), most likely in the mid-1640s. Sitting somewhere between a practical medical recipe book and theoretical chymical treatise, while being peppered with traditional causal explanations and Galenic precautions, Harley MS 6940 testifies to the erosion of the entrenched dichotomy between chymical and Galenic medicine in the mid-seventeenth century. Harley MS 6940 also lays bare how a learned physician used (and taught the use of) practice to confirm and sometimes challenge his learning, offering a counterpoint to recent scholarship that underscores the learning that apothecaries used to shore up their practice. Produced at the behest of a leading Royalist who sought both to acquire techniques for distilling and fermenting herbs and to advance his knowledge of chymical conceptions of spirits, seeds, and salts, the manuscript allows us to appreciate that the chymical art animated a broader set of individuals than the historiography often implies.

The Swiss physician and philosopher Theophrastus von Hohenheim, called Paracelsus (1493-1541) is known for his strong advocacy of medical alchemy. That his natural philosophy was tied to medical alchemy is perhaps uncontroversial, but just how it was so is less straightforward. This article provides an insight into the connection between the two by means of Paracelsus's concept of active agents, with an emphasis on fire, its master , and the associated term . I will show how these evolved in the thought of Paracelsus by taking an evolutionary view of his works. The complexity of his views comes to light as a result of employing the method of hybrid reading, which integrates the traditional close reading technique with the much more novel one of distant reading. The latter is part of the emerging field of digital and computational humanities, and involves the analysis of corpora by means of digital tools, including computer programming (Python). In the article, I will attempt to combine distant and close reading and showcase how such hybrid reading approaches may provide new insights into historical corpora.

In what follows I examine Diderot's chemically influenced vital materialism. Once condemned as "mechanistic," materialism has had something of a renaissance in recent decades as scholars have rediscovered a tradition of "vital materialism" which they have opposed to older, cruder forms of the idea, e.g. materialisms full of life, affect, chimiatry, and transformation. Sometimes these rediscoveries have attached themselves to a figure of the past, like Margaret Cavendish's metaphysics of active matter, or to a construct of the still-emerging future, like Karen Barad's quantum physics-nourished "agential realism" present in all of matter. Another question concerns the extent to which these revivals of "vital" or "active-matter" materialism should be traced back to older Renaissance naturalisms. In what follows, I return to Diderot and the question of his "vital materialism." Diderot draws both on older traditions, approvingly citing Van Helmont and gesturing towards a new chemistry of living matter and also speaks the language of scientific revolution, writing that "We are on the verge of a great revolution in the sciences." In earlier work I sought to connect this language of revolution in the sciences to the emergence of biology as a science. Here I focus on his chemically charged materialism.

This Ambix special issue explores premodern alchemical ideas and practices in their entanglements with medicine. It employs diverse methods, from traditional close reading to the new distant-reading framework of computational humanities, to investigate alchemical thought over a timespan of several centuries. In medieval times, everyday practices could offer heuristic models of material transformation - such as the fermentation of bread as a model for metallic transmutation (Schmechel). Paracelsus relied on "fire" to link his natural philosophy with his medical alchemy; new computational methods show how his ideas evolved over time (Hedesan). Early modern medical pluralism favoured the thriving of chemical medicine in Italy; diplomatic efforts introduced chemical remedies into acknowledged pharmacopoeias (Clericuzio). An English physician offers William Cavendish both practical distillation recipes and the hope of learning more about the principles of chemistry (Begley). In eighteenth-century France, Diderot draws on chemical ideas to blur the conceptual boundary between living and non-living matter (Wolfe). The papers largely adhere to integrated history and philosophy of science (iHPS) and to a pragmatist "operational ideal of knowledge" (Chang). They showcase the interdisciplinarity of premodern scientific thought and examine how medicine and alchemy, but also theory and (everyday) practice informed each other fruitfully across the ages.

This paper traces the analogy between the making of bread with ferment (leaven or yeast) and theories of metallic transmutation throughout the Middle Ages. For this purpose it surveys several medieval alchemical writings, including Hortulanus's influential . In this work, the ferment, an essential ingredient of the philosophers' stone, is portrayed less as an active agent and more as the passive, nutritive earth () which combines with the soul () in order to yield the stone (). I argue that the background of these theories has both a practical and a medical-theoretical dimension. The practical aspect derives from historical everyday practices of making bread from sourdough, and using old yeast "starter" as a kind of to speed up the fermentation of a new batch of fresh dough. The medical-theoretical framework for the understanding of ferment action was likely provided by the widely influential Galenic idea of whole substance action (Gr. καθ᾽ὅλην τὴν οὐσίαν, Lat. ), initially developed by Galen in pharmacology and later imported into alchemy via Arabic medicine. Together, these aspects converge into a successful model of "inoculation-emergence," which underlies many medieval and early modern theories of fermentation, both medical and alchemical.

Despite the increasing interest in Italian medicine, comparatively little attention has been paid to the establishment of iatrochemistry. Though this process spread throughout the Peninsula, Naples witnessed an impressive growth of chemical research and the outbreak of a conflict between the medical establishment and the chemical physicians. The purpose of this article is to explore the emergence of chemical medicine in Naples in the period that precedes the founding (1663) of the . In the first part of the seventeenth century, chemistry achieved recognition in settings like academies, pharmacies, hospitals, and monasteries. Chemical studies and the making of new remedies were spurred by the scientific exchange that Neapolitan established with scholars from different areas. The so-called medical pluralism and the recurrent outbreaks of epidemics stimulated the introduction of new chemical therapies, which coexisted with old ones The establishment of chemical medicine was triggered by Marco Aurelio Severino (1580-1656), who, besides promoting chemical remedies, resorted to chemical theories, including Paracelsian ones, to account for physiological processes. Severino was the mentor of the chemical physicians who gave rise to the . One of Severino's disciples was Giuseppe Donzelli (1596-1670), who fostered chemical remedies in Naples.

During the eighteenth century, authors of chemical treatises and courses on chemistry often introduced their work with a chapter devoted to the history of chemistry. While there may have been different reasons for the use of history, its importance was never seriously questioned. However, when Antoine Laurent Lavoisier (1743-1794) took a professional interest in chemistry in the early 1770s, he progressively became uneasy with this literary tradition. In this essay, I intend to explore the ways in which Lavoisier looked at the history of chemistry and to show how, from the 1780s onwards, he began to adopt a hostile attitude towards historical erudition. This vision, which culminated in the publication of the (Paris, 1789), was not only the result of a stylistic preference but constituted a direct attack on a way of doing chemistry from which Lavoisier intended to distance himself.

Research into the history of alchemy and Paracelsianism in Italy has highlighted the role of Italian courts in the sixteenth and seventeenth centuries as centres of elaboration and diffusion of alchemical knowledge. Among these, one of the best known is the Medici court which already dedicated spaces in the ducal foundry to the alchemical arts in the time of Cosimo I. This interest would remain alive with Francesco I and his son, Don Antonio de' Medici, one of the greatest supporters of Paracelsian medicine in Italy. This contribution presents previously unpublished sources, now preserved in the Archivio di Stato di Firenze and in the collection of the Biblioteca degli Intronati in Siena, that can help us reconstruct in greater detail some significant aspects of Medici alchemical engagement and can, above all, help further determine Paracelsus's influence in seventeenth century Florence.

Created and published in a printed volume in 1611, the emblem chosen by the literary Academy of the Umoristi is intriguing at multiple levels. At a time when the water cycle was still unknown, the image engaged the thorny question of how the evaporation of salty seawater, condensed into clouds, could subsequently pour down as sweet rain. Additionally, the Lucretian motto "Redit agmine dulci" audaciously evoked the philosophy of atoms. The combination of the image and the motto suggested looking at the meteorological phenomenon on display as a sort of natural distillation process, not different from the circulations taking place in the alembic. This enquiry will document how the Academy of the Umoristi was influenced in the choice of its emblem by the scientific Academy of the Lincei and how, towards the end of the seventeenth century, under the patronage of Christina of Sweden, the interconnection of alchemy and atomism alluded to in the academic emblem was reclaimed as a distinctive philosophical banner.

This article presents the results of a survey and a first assessment of the corpus of alchemical manuscripts retrieved from the Cairo Genizah, a storage room mainly intended for sacred writings that is attached to the Ben Ezra synagogue of Old Cairo. The alchemical manuscripts are described in their codicological and palaeographic features; their content is analysed in the context of the medieval production of alchemical texts in the surrounding Islamic world. The alchemical corpus of the Genizah represents a unique and widely unstudied source for our understanding of the relationship between Jews and alchemy in the medieval Mediterranean World.

Many of the "signs and tokens" described in alchemical texts relate to colour, from the Crow's Bill signifying putrefaction to the philosophical solvents disguised as Green Lions, Red Dragons, and Grey Wolves. While the process of yellowing, or citrination, often appears in medieval recipes, it seems to have interested commentators less than the more familiar processes of blackening, whitening, or reddening. Yet beyond these canonical colours, yellowness turns out to be ubiquitous in alchemy and its associated craft practices, both in Latin texts and vernacular translations. This paper uses source criticism and experimental reconstruction to interrogate the role of yellowness at the beginning, middle, and end of practice, focusing on fifteenth- and sixteenth-century England. As starting ingredients, yellow vitriol and litharge offered the potential for transmutation but also posed problems for identification and preparation. As an intermediate stage, yellowness offered promising signs of future success, in the form of dramatic colour changes and unexpected products. But yellowness also offered an end in itself, as appears from the many citrination processes attested in recipe collections which aimed to imitate the properties of gold - suggesting that yellowing was prized as a significant indicator of chemical change across diverse areas of craft practice.

Mediaeval Arabic technical literature shows a keen interest in yellow dyes, paints, varnishes, inks, and even perfumes. Recipes reveal that yellow was viewed as just one step away from gold, with preparations for these two colours often sharing ingredients and techniques. In the unfolding of procedures and applications to different materials, from skin to textiles, Arabic sources also offer a glimpse into daily life and shared tastes, presenting luxury objects along with their imitations. This paper traces the role played by yellow and gold in inks, cosmetic dyes, and coloured, scented fabrics, exploring the textual dimension of these recipes, their technical features, and their social role between the court and the street. It also presents translations of several important recipes for yellow and gold dyes, which illustrate their diversity of applications, while also addressing such material problems as durability and substitution.

Nitric acid became commonly available in the seventeenth century. Since then, it held the interest of chemists, especially those interested in the art of dyeing. Due to what is now called the xanthoproteic reaction (from Greek , describing shades of yellow), nitric acid produces a stable yellow colouration in proteinaceous materials, such as wool, silk, and bones. The chemistry of this reaction is well understood today. Less well-known is that it held the interest of dyers in the past. Dyers considered the ability of nitric acid to give a yellow colour to certain substances a solution to giving materials a durable, that is, a lasting, yellow colour. Yellow, indeed, posed a problem in the art of dyeing. Before the discovery of synthetic dyes in the mid-nineteenth century, there were no organic yellow dyes with long-term colour stability. Using historical dyeing manuals and chemistry treatises, combined with our practical engagement with the processes they describe, this paper traces how, between the seventeenth and nineteenth centuries, dyers explored nitric acid while examining the durability of yellow colourations. Based on these explorations into nitric acid, the chemical arts developed theories about the nature of colour, and about the causes for its relative permanence.

Ancient Greek colour terminology captures brightness, light, and brilliance rather than clear-cut portions of the chromatic spectrum, as scholars agree today. This also applies to the rich semantic of yellow, which we investigate starting from a philosophical and theoretical perspective. We then shift our focus to Graeco-Roman technical writings dealing with alchemical dyes, cosmetics, and other crafts that made use of the same set of ingredients and colouring substances. We compile a complete list of yellow-dyeing plants used in antiquity, which will update and enlarge the lists currently available in secondary literature on the topic, such as the seminal catalogue by Robert J. Forbes. Drawing on these data and on laboratory reconstructions, we address two main questions. First, which shades of yellow were usually associated with the colour of gold, and how were these tints produced by ancient craftsmen and alchemists? And second, how did these procedures contribute to the ancient discourse on the colour of gold and its artificial reproduction?