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Magnenus, Johann Chrysostom


(b. Luxeuil-les-bains, France, ca. 1590; d. 1679[?])

natural philosophy, medicine.

Little is known of Magnenus’ family and early life other than that he received the M. D. from the University of Dôle. He traveled for a period in Italy, becoming well-known as a doctor, and was subsequently appointed professor of medicine at the University of Pavia, where several years later he also secured the chair of philosophy. In 1660 Magnenus was chosen personal physician to the count of Fuensaldagne, ambassador to the French court, whom he accompanied to Paris.

Magnenus’ importance in the history of science derives from his attempt to reinstate the Democritean theory of atomism as a respectable part of seventeenth-century natural philosophy. His Demoncritusreviviscens (1646), though marking less of a break with tradition than Gassendi’s contemporaneous revival of Epicureanism, was typically regarded (for example, by Boyle) as instrumental in establishing a comprehensive alternative to Aristotelianism. Magnenus adopted Democritus’ view that matter is composed of physically indivisible atoms which differ in size and shape for each element. He rejected the concept of materia prima, asserting that the elements are not interconvertible but preserve their atomic identity and properties when combined chemically.

Eight fundamental proposition for the existence of atoms were advanced by Magnenus, based on mathematical as well as chemical and other experimental considerations. Much of the experimental evidence was drawn from Daniel Sennert’s Hypomnemata physica (Frankfurt, 1636) and Jacques Gaffarel’s Curiositez inouyes (Paris, 1629), although he also cited the work of more prominent scientist of the period, including Galileo. Magnenus countered mathematical objections to the atomic theory by arguing that the continuum could not be built up from mathematical points, whether their number of finite, indeterminate, or infinite. Matter, he averred, consisted of atoms having definite dimensions (unlike mathematical points) which represent the physical limit to material division. There were three elementary atoms: fire, water, and earth. Each possessed specific properties and gave rise, by their various combinations, to all other natural substances. Air, because it had no characteristic properties but could assume, at different times, all primary properties, was not an element. It functioned as the neutral medium for propogating the specific properties of the elements during interaction and served to prevent a vacuum by filling the pores of compound bodies.

Magnenus’ restoration of Democritean atomism was limited, to be sure. Unlike Democritus, he denied the existence of a void; his retention of Aristotelian substantial forms (now inherent in individual atoms) and his explanation of combination by an innate tendency to union further separates his system from classical atomism. Moreover, while the widespread reading and citation of his work facilitated the acceptance of atomistic ideas in general, his theory must be distinguished from those corpuscular philosophies, like Gassendi’s and Boyle’s, which sought to explicate natural phenomena solely on the basis of the size, shape, and movement of imperceptible particles. Magnenus accepted certain of the tenets of seventeenth-century mechanical philosophy but amalgamated them into a broader system incorporating traditional modes of qualitative chemical explanation. Thus he is representative of that atomist school which, during the seventeenth and eighteenth centuries, posed an alternative to strict mechanism in science.


I. Original Works. Magnenus’ major scientific publication is Democritus reviviscens sive de atomis. Addita est Democriti vita (pavia, 1646; Leiden, 1648, 1648; London-The Hague, 1658). Other writings in include: De tabaco exercitationes quatuordecim (Pavia, 1648; Pavia-The Hague, 1658), which treats of the medical usage and effects of tobacco; and De manna liber singularis (Pavia, 1648; 2nd ed., Pavia-The Hague, 1658).

II. Secondary Literature. For Magnenus’ life and work, see J. Güsgens, Die Naturphilosophie des Joannes Chrysostomus Magnenus (Bonn, 1910). F. Ueberweg, Grundriss der Geschichte der Philosophie, rev. ed., III (Berlin, 1924), 171–174, places Magnenus among the French natural philosophers of the first half of the seventeenth century. Other assessments of his atomic theory include G. B. Stones, “The Atomic View of Matter in the XVth, XVIth, and XVIIth Centuries,” in Isis, 10 (1928), 458–459; and J. R. Partington, A History of Chemistry, II (London, 1961), 455–458.

Martin Fichman

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