Stevin Seminar: The Substance of Light in the Lenses of Tschirnhaus. Philosophy, Industry, Instruments, and Patronage around 1700

Abstract: In the 1690s Walther Ehrenfried von Tschirnhaus (1651-1708) in Saxony developed a new kind of burning lenses of unprecedented power. They produced immense heats that would melt and vitrify all kinds of substances. The lenses branched out to all kinds of places and projects. To Tschirnhaus’s attempts around 1680 to secure patronage from the Sun King for his burning mirrors and Christiaan Huygens’s analysis of caustics. To Tschirnhaus’s involvement in the Saxony industrial innovations that would bring forward Meissner porcelain. To the interests of Amsterdam amateurs in experimental display as well as hetorodox philosophy and Wilhelm Homberg’s Paris experiments on the transmutation of metals by light. In this presentation I will sketch these linkages of knowledge practices around 1700. At the same time I will single out the focus of Tschirnhaus’s lenses as a turning point in the conception of light. What, after all, is burning in the focus: rays, forces, particles, or some substance?

Speaker: Fokko Jan Dijksterhuis is Extraordinary Professor of Cultural History of the Modern Period at the Department of History of the Vrije Universiteit and Associate Professor of History of Science at the Centre for Studies of Science and Technology of the University of Twente.