The magnet served three interests of Restoration mechanical philosophers: it provided a model of cosmic forces, it suggested a solution to the problem of longitude determination, and evidence of its corpuscular mechanism would silence critics. An implicit condition of William Gilbert's ‘magnetic philosophy’ was the existence of a unique, immaterial magnetic virtue. Restoration mechanical philosophers, while claiming descent from their compatriot, worked successfully to disprove this, following an experimental regime of Henry Power. Magnetic philosophy lost its coherence and became subsumed (...) in the study of effluvia. This contradiction of a distinct, yet mechanical magnetic philosophy came to a head in 1684 in an argument between Robert Hooke and Martin Lister. An effluvial explanation of magnetism introduced great complexity to the North-seeking behaviour of compass needles, and undermined the already troubled longitude programme. Thus magnetic philosophy no longer furthered the interests which had maintained it, and it was abandoned. (shrink)

This paper draws attention to the crucial importance of a new kind of precisely defined law of nature in the Scientific Revolution. All explanations in the mechanical philosophy depend upon the interactions of moving material particles; the laws of nature stipulate precisely how these interact; therefore, such explanations rely on the laws of nature. While this is obvious, the radically innovatory nature of these laws is not fully acknowledged in the historical literature. Indeed, a number of scholars have tried to (...) locate the origins of such laws in the medieval period. In the first part of this paper these claims are critically examined, and found at best to reveal important aspects of the background to the later idea, which could be drawn upon for legitimating purposes by the mechanical philosophers. The second part of the paper argues that the modern concept of laws of nature originates in René Descartes's work. It is shown that Descartes took his concept of laws of nature from the mathematical tradition, but recognized that he could not export it to the domain of physico-mathematics, to play a causal role, unless he could show that these laws were underwritten by God. It is argued that this is why, at an early stage of his philosophical development, Descartes had to turn to metaphysics. (shrink)

In A Treatise of Artificial Magnets, John Michell observes, Not being aware of this property [i.e. the equality of attraction and repulsion], he [Gilbert] concluded from some experiments he had made, not very irationally [sic], that the Needle was not attracted by the magnet, but turned into its position by, what he calls, a disponent virtue […]. For Michell, the disponent virtue 1 is the underlying cause of magnetic phenomena in Gilbert’s treatment. He is not alone. Ridley and Carpenter also (...) read Gilbert’s magnetism as positing a disponent virtue.2 I agree. In this paper, I show what it would entail to treat Gilbertian magnetism as... (shrink)

Panni les aspects remarquables de l'Aristarque (1644) de Roberval, on relève la répétition fréquente dans le texte de l'abréviation« P.N.E.M.». Ces lettres signifient « pondere, numero et mensura ». Ces mots sont tirés du Livre de la Sagesse, XI, 20: « Pondere, mensura, numero Deus omnia fecit » (Vulgate). Ce verset est cité chez beaucoup d'auteurs qui veulent louer Dieu Géomètre. Cependant, Roberval n'est nullement pieux. Il s'agit donc ici de savoir pourquoi il se sert de « P.N.E.M.» dans son (...) texte. Roberval se montre-t-il ainsi solidaire de ses confrères mathématiciens du Collège royal, dont le verset serait la devise? (shrink)

This dissertation deals with the alchemical activities of the English natural philosopher Robert Boyle . ;The study begins by setting down a consistent and defensible terminology for discussing a period during which time the words alchemy and chemistry were synonymous. A review of the three centuries of secondary literature on Boyle then reveals how his image has been successively reformed and tailored to fit prevailing apologetic or historiographic programmes, almost always with the effect of modernizing him and his interests and (...) further burying his already obscure alchemical interests. A radically new interpretation of the Sceptical Chymist is then presented, developed by a newly rigorous reading of the work--together with its 1680 appendix--in terms of its context and sources, and with a much more nuanced appreciation of the competing schools of seventeenth century "chymistry." The work is thus revealed as not critical of the aims or methods of traditional alchemical masters, or adepti, but rather of the "unphilosophical" practice of Paracelsian pharmacists and the systematizing of textbook writers. Boyle's own positive view of transmutational alchemy is then unambiguously presented by a consideration of his "lost" Dialogue on the Transmutation and Melioration of Metals now reconstructed from scattered surviving fragments and presented here in full for the first time. The text shows Boyle's unflinching belief in the reality of the Philosophers' Stone and its powers, and his dissatisfaction with those who denied it. Different kinds of transmutation within traditional alchemy are described, alongside evidence for Boyle's maintenance of these traditional divisions. Boyle's own witness of transmutation is then recounted along with his attempts to contact adepti, thus involving him in a diverse array of social and scientific networks across Europe. ;Boyle's alchemical programme is next detailed, including his reading and writing of alchemical texts, his adoption of alchemical means of communication , and his experimental attempts to prepare alchemical arcana. In this last regard, his forty-year search for the Philosophical Mercury and its correct manipulation is chronicled. Finally, Boyle's motivations are explored. Boyle's interest in chrysoppoeia was not fueled primarily by the promise of medicines, gold, or new natural philosophical knowledge devolving from the Stone, but rather by his belief that the Stone could function as a medium for facilitating communication with angels and other spirits. As such, it could potentially manifest spirit activity and thus act as a powerful weapon against atheism. ;This study reveals Boyle as much less of a modern and revolutionary than presentist, positivist, heroic, or even the new sociological schools would have him. Rather, he is here resituated in a complex web of contemporary questions and currents of thought, and involved in the debate of an important question of the day. Alchemy was a chief concern of Robert Boyle and as such it must be fully integrated into our portrayal of him, and by extension, of his time--a critical period in the development of modern science as a whole, and of early modern chemistry in particular. The spiritual functions with which Boyle eventually endowed alchemy promoted it to a central position in his thought as a whole, functioning then as a middle term mediating between his two chief missions--the advancement of natural philosophy and the defense and propagation of Christianity. (shrink)