The Mysteries of the Bologna Stone, the First Artificially Produced Phosphorescent Material

Around 1602, a shoemaker and part-time alchemist from Bologna picked up a mineral in the hills outside the city. While he failed to produce gold with it, he found to his surprise that the stones after being treated and then exposed to sunlight, would glow in the dark like burning coals. The fame of his “sponge of light” spread across Europe, attracting the attention of Galileo and many others, and becoming a sought-after marvel of chymistry. Yet even though detailed recipes for preparing it were published several times, no one outside of Bologna could get the process to work. Thus by the 1660s, the method was considered a “lost secret.” In the 1680s however, Wilhelm Homberg, a young chymist fascinated by the interaction of light with matter, learned how to prepare it better than anyone had done before. This lecture recounts the history of the “Bologna Stone,” explores why so many practitioners failed to get the process to work, and presents my work in reproducing Homberg’s process, discovering along the way a key reason for the seventeenth-century failures.
 
Speaker Biography
 
Lawrence Principe holds the Drew Professorial Chair at Johns Hopkins University in the Department of the History of Science and the Department of Chemistry. His research focuses on the Medieval and early modern periods, with emphasis on the history of alchemy and chemistry and the science-religion dynamic. He is the author of more than sixty scholarly articles and ten books, including The Scientific Revolution: A Very Short Introduction, written for a popular audience and now available in nine languages, The Secrets of Alchemy (2013), and most recently The Transmutations of Chymistry: Wilhelm Homberg and the Académie Royale des Sciences published in 2020. He is the recipient of a Guggenheim Fellowship, the Francis Bacon Medal from Caltech, the Prix Franklin-Lavoisier from the Fondation de la Maison de la Chimie (Paris), and the History of Chemistry Award from the American Chemical Society for his contributions to the history of science, as well as the St. Albert the Great Prize from the Society of Catholic Scientists for his work on science and religion.