Corpuscularianism is a physical theory that supposed all matter to be composed of minute particles, which became important in the seventeenth century. Among the leading corpuscularians were Pierre Gassendi, Robert Boyle, and John Locke.
Corpuscularianism is similar to the theory of atomism, except that where atoms were supposed to be indivisible, corpuscles could in principle be divided. In this manner, for example, it was theorized that mercury could penetrate into metals and modify their inner structure, a step on the way towards the production of gold by transmutation. Corpuscularianism was associated by its leading proponents with the idea that some of the properties that objects appear to have are artifacts of the perceiving mind: "secondary" qualities as distinguished from "primary" qualities. Corpuscularianism stayed a dominant theory for centuries and was blended with alchemy by early scientists such as Robert Boyle and Isaac Newton in the 17th century.
The philosopher Thomas Hobbes used corpuscularianism to justify his political theories in Leviathan. It was used by Newton in his development of the corpuscular theory of light, while Boyle used it to develop his mechanical corpuscular philosophy, which laid the foundations for the Chemical Revolution.
Alchemical Corpuscularianism 
William R. Newman traces the origins from the fourth book of Aristotle, Meteorology. The "dry" and "moist" exhalations of Aristotle became the alchemical 'sulfur' and 'mercury' of the eighth-century Islamic alchemist, Jābir ibn Hayyān (721–815), and others. The thirteenth-century Summa perfectionis of Pseudo-Geber, an Italian Franciscan or Spanish alchemist sometimes identified as Paul of Taranto, contains a theory where unified sulfur and mercury corpuscles, differing in purity, size, and relative proportions, form the basis of a much more complicated process.
Importance to the development of modern scientific theory 
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Several of the principles which corpuscularianism proposed became tenets of modern chemistry.
- The idea that compounds can have secondary properties that differ from the properties of the elements which are combined to make them became the basis of molecular chemistry.
- The idea that the same elements can be predictably combined in different ratios using different methods to create compounds with radically different properties became the basis of stoichiometry, crystalography, and established studies of chemical synthesis.
- The ability of chemical processes to alter the composition of an object without significantly altering its form is the basis of fossil theory via mineralization and the understanding of numerous metallurgical, biological, and geological processes.
- Brown, Sable (2005-01-01). Philosophy. Lotus Press. pp. 53–. ISBN 978-81-89093-52-5. Retrieved 8 June 2010.
- The Mechanical Philosophy - Early modern 'atomism' ("corpuscularianism" as it was known)
- Levere, Trevor, H. (2001). Transforming Matter – A History of Chemistry from Alchemy to the Buckyball. The Johns Hopkins University Press. ISBN 0-8018-6610-3.
- Corpuscularianism - Philosophical Dictionary
- Ursula Klein (July 2007), "Styles of Experimentation and Alchemical Matter Theory in the Scientific Revolution", Metascience (Springer) 16 (2): 247–256 , doi:10.1007/s11016-007-9095-8, ISSN 1467-9981
- Late medieval and early modern corpuscular matter theories Volume 1 of Medieval and Early Modern Science, Christoph Lüthy, J. E. Murdoch, William R. Newman BRILL, 2001 ISBN 978-90-04-11516-3
- Newman, William Royall (2006). Atoms and alchemy: chymistry and the experimental origins of the scientific revolution. University of Chicago Press. ISBN 978-0-226-57697-8. Retrieved 8 June 2010.
- Fredric L. Holmes and Trevor H. Levere. Instruments and Experimentation in the History of Chemistry. MIT Press, 2000. ISBN 978-0-262-08282-2.
- Moran, Bruce T. (2005), Distilling knowledge: alchemy, chemistry, and the scientific revolution, Harvard University Press, p. 146, ISBN 0-674-01495-2, "a corpuscularian tradition in alchemy stemming from the speculations of the medieval author Geber (Jabir ibn Hayyan)"
- The Mineral Exhalation Theory of Metallogenesis in Pre-Modern Mineral Science JOHN A. NORRIS AMBIX, Vol. 53, No. 1, March 2006, 43–65 © Society for the History of Alchemy and Chemistry 2006 doi:10.1179/174582306X93183