A science of appearances

This dissertation examines how scientists in nineteenth-century England grappled with the perceptual challenges involved in observing the electric spark. Focusing on how this elusive object was visualized through demonstrations, optical instruments, and pictures allows us to recover an insistent preoccupation with visuality in Victorian physics. This project reconstructs the forgotten visual practices of the early physics laboratory and connects them to the Victorian fascination with optical illusions, to the development of new visual media like photography and cinema, and to an orientation towards description and classification more commonly associated with natural history and the field sciences. It places physics at the intersection of a set of cultural transformations that extended far beyond the rarefied confines of the scientific laboratory, defining a vital new context for the emergence not only of modern physics but of nineteenth-century "visual modernism." The story begins in the 1830s, when Michael Faraday and Charles Wheatstone exposed the temporal structure of the seemingly instantaneous electric spark in their lectures and private experiments by mastering and exploiting