But there is some difference between those figures that perceive light, and those that are light themselves; for when we sleep, there is made the figure of light, but not from a copy; but when the eye seeth light, that figure is made from a copy of the real figure of the Sun; but those lights which are inherent, as in Glow-worms-tails, are original lights, in which is as much difference as between a Man and his Picture; and as for the swiftness of the Motions of light, and the violence of the Motions of fire, it is very probable they are so, but they are a certain particular kind or sort of swift and violent motions; neither will all sorts of swift and violent motions make fire or light, as for example the swift and violent Circular motion of a Whirlewind neither makes light nor fire; Neither is all fire light, nor all light fire, for there is a sort of dead fire, as in Spices, Spirits, Oyles, and the like; and several sorts of lights, which are not hot, as the light which is made in Dreams, as also the inherent lights in Glow-worms, Cats-eyes, Fish-bones, and the like; all which several fires and lights are made by the self-moving matter and motions distinguishable by their figures, for those Motions make such a figure for the Suns light, such a figure for Glow-worms light, such a figure for Cats-eyes light, and so some alteration in every sort of light; The same for Fire, onely Fire-light is a mixt figure, as partly of the figure of Fire, and partly of the figure of Light: Also Colours are made after the like manner, _viz._ so many several Colours, so many several Figures; and as these Figures are less or more different, so are the Colours.