easily without any pressure or reaction; I will not say, that there is no pressure or reaction in Nature, but pressure and reaction doth not make perception, for the sensitive and rational parts of matter make all perception and variety of motion, being the most subtil parts of Nature, as self-moving, as also divideable, and composeable, and alterable in their figurative motions, for this Perceptive matter can change its substance into any figure whatsoever in nature, as being not bound to one constant figure. But having treated hereof before, and being to say more of it hereafter, this shall suffice for the present, remaining always, Madam, _Your constant Friend,_ _and faithful Servant._ [1] _C._ 25. _a._ 1. [2] _Art._ 2. XIX. _MADAM,_ To discourse of the World and Stars, is more then I am able to do, wanting the art of Astronomy and Geometry; wherefore passing by that Chapter of your Author, I am come to that[1] wherein he treats of Light, Heat and Colours; and to give you my opinion of Light, I say, it is not the light of the Sun, that makes an Animal see, for we can see inwardly in Dreams without the Suns light, but it is the sensitive and rational Motions in the Eye and Brain that make such a figure as Light; For if Light did press upon the Eye, according to your _Authors_ opinion, it might put the Eye into as much pain as Fire doth, when it sticks its points into our skin or flesh. The same may be said of Colours, for the sensitive motions make such a figure, which is such a Colour, and such a Figure, which is such a Colour; Wherefore Light, Heat and Colour, are not bare and bodiless qualities, but such figures made by corporeal self-motions, and are as well real and corporeal objects as other figures are; and when these figures change or alter, it is onely that their motions alter, which may alter and change heat into cold, and light into darkness, and black colour into white. But by reason the motions of the Sun are so constant, as the motions of any other kind of Creatures, it is no more subject to be altered then all the World, unless Nature did it by the command of God; for though the Parts of self-moving Matter be alterable, yet all are not altered; and this is the reason, that the figure of Light in our eye and brain is altered, as well as it is alterable, but not the real figure of the Sun, neither doth the Sun enter our eyes; and as the Light of the Sun is made or patterned in the eye, so is the light of Glow-worms-tails, and Cats-eyes, that shine in the dark, made not by the Sun's, but their own motions in their own parts; The like when we dream of Light, the sensitive corporeal motions working inwardly, make the figure of light on the inside of the eye, as they did pattern out the figure of light on the outside of the eye when awake, and the objects before them; for the sensitive motions of the eye pattern out the figure of the object in the eye, and the rational motions make the same figure in their own substance.