Abstract: What do we learn about science from theatre; and what do we learn about theatre from science? There are innumerable sites of public science–from television specials such as “Cosmos,” science and natural history museums, and much more–that reflect a theatrical and artistic approach to communicating science. However, this contemporary practice has a long pre-history, one that weaves in and through the history of theatrical movements, the innovation of light and power, and the development of science as a modern discipline. Performances of science—from the spectacular to the mundane—were essential features of science in the nineteenth century. Demonstrations, displays, lectures, and other kinds of performances offered spectators access into the emerging and developing practices of scientific knowledge, even as those in positions of authority sought to inscribe and define the boundaries of the practices. Both knowledge systems—theatre and science—contributed to the other and examining both together helps to reveal how we think, innovate, and understand the world. Aileen Robinson, historian of 19th century theatre and science, will present the history of the development of Pepper's Ghost, a stage trick for conjuring ghosts that relied upon (and spurred) innovations in physical and material science.