_Thirdly_, They may ask me, if sight be made in the eye, and proceeds not from the outward object, what is the reason that we do not see inwardly, but outwardly as from us? I answer, when we see objects outwardly, as from us, then the sensitive motions work on the outside of the organ, which organ being outwardly convex, causes us to see outwardly, as from us, but in dreams we see inwardly; also the sensitive motions do pattern out the distance together with the object: But you will say, the body of the distance, as the air, cannot be perceived, and yet we can perceive the distance; I answer, you could not perceive the distance, but by such or such an object as is subject to your sight; for you do not see the distance more then the air, or the like rare body, that is between grosser objects; for if there were no stars, nor planets, nor clouds, nor earth, nor water, but onely air, you would not see any space or distance; but light being a more visible body then air, you might figure the body of air by light, but so, as in an extensive or dilating way; for when the mind or the rational matter conceives any thing that hath not such an exact figure, or is not so perceptible by our senses; then the mind uses art, and makes such figures, which stand like to that; as for example, to express infinite to it self, it dilates it parts without alteration, and without limitation or circumference; Likewise, when it will conceive a constant succession of Time, it draws out its parts into the figure of a line; and if eternity, it figures a line without beginning, and end. But as for Immaterial, no mind can conceive that, for it cannot put it self into nothing, although it can dilate and rarifie it self to an higher degree, but must stay within the circle of natural bodies, as I within the circle of your Commands, to express my self Madam, _Your faithful Friend,_ _and obedient Servant._ XXI. _MADAM,_