In 1700 Johann Bernoulli (1667-1748) brought barometric light under control with his 'new phosphor'. It initiated a wave of inquiries that resulted, among other things, in the development of the first electrical engines. Bernoulli's apparatus was just one instance of phosphor at that time. Light-bearers attracted wide interest of early modern inquirers: stones, animals, the new substance created from urine, the luminescence of vacuum, or the bright light of foci. These phosphors indicated new conceptions of light as a reactive substance that could be operated and employed to create material transformations. In this way, light became the heart of inquiries into matter and forces that bring together early Enlightenment developments in experimental philosophy. Modern disciplines tend to comminute the historiography of early modern natural philosophy. To overcome this, I approach the history of phosphors from the perspective of early-eighteenth-century protagonists like Bernoulli, Gottfried Wilhelm Leibniz (1646-1716), Wilhelm Homberg (1652-1715), Daniël Gabriël Fahrenheit (1686-1736).
