This sir Isaac seems, by degrees, to have understood; for he says, in his second letter: "The reason why matter, evenly scattered through a finite space, would convene in the midst, you conceive the same with me; but, that there should be a central particle, so accurately placed in the middle, as to be always equally attracted on all sides, and, thereby, continue without motion, seems to me a supposition fully as hard as to make the sharpest needle stand upright upon its point on a looking-glass. For, if the very mathematical centre of the central particle be not accurately in the very mathematical centre of the attractive power of the whole mass, the particle will not be attracted equally on all sides. And much harder is it to suppose all the particles, in an infinite space, should be so accurately poised, one among another, as to stand still in a perfect equilibrium. For I reckon this as hard as to make not one needle only, but an infinite number of them, (so many as there are particles in an infinite space,) stand accurately poised upon their points. Yet I grant it possible, at least, by a divine power; and, if they were once to be placed, I agree with you, that they would continue in that posture without motion, for ever, unless put into new motion by the same power. When, therefore, I said, that matter evenly spread through all space, would convene, by its gravity, into one or more great masses, I understand it of matter not resting in an accurate poise." Let not it be thought irreverence to this great name, if I observe, that by "matter evenly spread" through infinite space, he now finds it necessary to mean "matter not evenly spread." Matter not evenly spread will, indeed, convene, but it will convene as soon as it exists. And, in my opinion, this puzzling question about matter, is only, how that could be that never could have been, or what a man thinks on when he thinks on nothing. Turn matter on all sides, make it eternal, or of late production, finite or infinite, there can be no regular system produced, but by a voluntary and meaning agent. This the great Newton always asserted, and this he asserts in the third letter; but proves, in another manner, in a manner, perhaps, more happy and conclusive. "The hypothesis of deriving the frame of the world, by mechanical principles, from matter evenly spread through the heavens, being inconsistent with my system, I had considered it very little, before your letter put me upon it, and, therefore, trouble you with a line or two more about it, if this comes not too late for your use.