But if we conceive of an eye at, or elsewhere, turned toward a torch, the parts of the flame, which are in continuous motion, will, by very rapid vibrations or disturbances, constantly press the subtle matter from all sides more strongly than they do in the dark, and consequently, due to the plenum, they will press it as far as the fundus of the eye; the optic nerve, being more compressed than usual, and disturbed by vibrations, will excite in the soul a sensation of light or of bright and vivid whiteness.