forward, but backwards, and side-ways, and seems indeed much rather to be Homogeneous or similar to those pores, which we may with great probability believe to be the channels of pellucid bodies, not directed, or more open any one way, then any other, being equally pervious every way. And, according as these pores are more or greater in respect of the interstitial bodies, the more transparent are the so constituted concretes; and the smaller those pores are, the weaker is the Impulse of light communicated through them, though the more quick be the progress.
Upon this Occasion, I hope it will not be altogether unseasonable, if I propound my conjectures and Hypothesis about the medium and conveyance of light.
I suppose then, that the greatest part of the Interstitia of the world, that lies between the bodies of the Sun and Starrs, and the Planets, and the Earth, to be an exceeding fluid body, very apt and ready to be mov'd, and to communicate the motion of any one part to any other part, though never so far distant: Nor do I much concern my self, to determine what the Figure of the particles of this exceedingly subtile fluid medium must be, nor whether it have any interstitiated pores or vacuities, it being sufficient to solve all the Phænomena to suppose it an exceedingly fluid, or the most fluid body in the world, and as yet impossible to determine the other difficulties.
That being so exceeding fluid a body, it easily gives passage to all other bodies to move to and fro in it.
That it neither receives from any of its parts, or from other bodies; nor communicates to any of its parts, or to any other body, any impulse, or motion in a direct line, that is not of a determinate quickness. And that when the motion is of such determinate swiftness, it both receives, and communicates, or propagates an impulse or motion to any imaginable distance in streight lines, with an unimaginable celerity and vigour.
That all kind of solid bodies consist of pretty massie particles in respect of the particles of this fluid medium, which in many places do so touch each other, that none of this fluid medium interposes much after the same mannner (to use a gross similitude) as a heap of great stones compose[errata 1] one great congeries or mass in the midst of the water.
That all fluid bodies which we may call tangible, are nothing but some more subtile parts of those particles, that serve to constitute all tangible bodies.
That the water, and such other fluid bodies, are nothing but a congeries of particles agitated or made fluid by it in the same manner as the particles of Salt are agitated or made fluid by a parcel of water, in which they are dissolv'd, and subsiding to the bottom of it, constitute a fluid body, much more massie and dense, and less fluid then the pure water it self.
That the air on the other side is a certain company of particles of quite another kind, that is, such as are very much smaller, and more easiely moveable by the motion of this fluid medium; much like those very subtile parts of Cochenel, other very deep tinging bodies, where by a very
Errata
