Mihnea Dobre

The glass drop is a tear-shaped object with many curious properties. Although having a fragile tail, its main body is hard to break. On the other hand, breaking such a drop produces a loud noise and many very small particles of glass. In the seventeenth century, these objects became the focus of both experimental and natural philosophical investigation. In this article, I examine the ways in which various natural philosophers have dealt with glass-drops. This is neither a complete enumeration of the countless attempts to explain the object and its associated phenomena, nor a search for its origins. Rather, this study offers a glimpse into what was at stake in the inclusion of the glass drop—a new scientific object—into natural philosophy. I shall argue that a full description of the drop and of its properties required both experiment and speculation.

The appearance of scientific journals in the second half of the seventeenth century not only presented new opportunities for the dissemination of knowledge, but also offers the historian a privileged view of the shared knowledge within the scientific community. The Journal des Sçavans, founded in 1665, proclaimed its ambition to disseminate news about books and people concerning the République des lettres. Given the reportedly high interest in and opposition to the rise of Cartesianism among contemporary philosophers, this paper explores the discussion of Cartesianism within the pages of the Journal. It is shown that debates on Cartesianism formed only a small portion of the articles in the Journal. Although the majority of commentaries referred to the metaphysical foundations of Cartesian philosophy, a considerable number of instances were found referring to empirical tests of the theory. Finally, as the Journal does not mention the condemnations or censorship of Cartesianism, we cannot speak of a general feeling of hostility against Cartesian philosophers among the editors or intended audience of the Journal.

Notoriously, Descartes does not have a concept of space. Or more precisely, he takes space as indistinguishable from matter or extension. Yet, to some of his contemporaries, his physics was successful at providing mechanical descriptions of the natural world. In this paper, I discuss the problem of “space” within a larger Cartesian framework, focusing on a case of an experimentally-minded Cartesian who took up the challenge provided by Descartes’s restrictive ontology and tried to accommodate it to experimental trials. One of the most famous debates of seventeenth-century natural philosophy concerns the existence of the vacuum. New instruments were built with the specific purpose of providing clear evidence to support this claim. While a large secondary literature has been devoted to this problem, we still lack a study of the Cartesians involved. Most of the time, Descartes’s followers are taken to merely repeat his words about the contradictory nature of the vacuum, hence their experiments are portrayed as rather misplaced practices. At most, one would find in the literature a discussion about the pedagogical value of these experiments. The consequence is that new experimental approaches provided by Cartesians after Descartes’s death in 1650 are, unfortunately, neglected. By building upon a recent volume, Cartesian Empiricisms, my aim in this paper is to explore the notion of space within Cartesian experimentalism. In doing so, I shall refer to the works of Burchard de Volder, Jacques Rohault, and Samuel Clarke’s annotations of Rohault’s text. Some of the questions I would like to address are as follows: why would a Cartesian natural philosopher perform experiments that are clearly connected to a concept of independent space? What would be the expected outcome? How does the theory (in this case, the Cartesian matter theory) relate to empirical evidence? And how would the latter influence the former? Such questions are relevant for the history of experiment in the early modern period. At the same time, they offer more insights into one of the most intricate problems of Cartesian philosophy, the relation between metaphysics and physics.