'Sherrington's initial foray into the study of visual sensations, published in 1897, relied on an illusion-generating device in the shape of a multi-colored disc that could be rotated to produce the sensation of a single color. This suggested a direct parallel between two phenomena that had been current amongst philosophers of optics since the eighteenth century (Wade 2005, 112–116; Mannoni [1994] 2000, 204–212). These were studies relating on the one hand to the shortest time that an eye could be exposed to a flash of light and an associated light-sensation be experienced, and on the other to the production of a sense of continuous experience via repeated exposure to radically different visual stimuli. Regarding the first of these, eighteenth- and especially nineteenth-century natural philosophers had come to concern themselves with a wide range of phenomena that occurred over very short intervals of time. The nature of sparks, bubbles, and vibrations (to give three amongst many possible examples) were interrogated using tools designed for the visual “fixing” of transient phenomena (Ramalingam 2015; Canales 2009, chap. 5; Schaffer 2004, esp. 170–177).' (453-454)