_A._ It may be it is the figure that makes the difference. For though figure be not motion, yet it may facilitate motion, as you see commonly the breadth of a heavy body retardeth the sinking of it. And the cause of it is, that it makes the air have farther to go laterally, before it can rise from under it. For suppose a body of quicksilver falling in the air from a certain height, must it not, going as it does toward the centre of the earth, as it draws nearer and nearer to the earth, become more and more slender, in the form of a solid sector? And if it have far to go, divide itself into drops? This figure of a solid sector is like a needle with the point downward, and therefore I should think that facilitating the motion of it does the same that would be done by increasing the endeavour. _B._ Do not you see that this way of facilitating is the same in water, and in all other fluid heavy bodies? Besides, your argument ought to be applicable to the weighing of bodies in a pair of scales, which it is not, for there they have no such figure; it should also hold in the comparison of gravity in hard and fluid bodies. _A._ I had not sufficiently considered it. But supposing now, as you do, that both heavy and hard bodies, in their smallest parts, were made so in the creation; yet, because quicksilver is harder than water, a drop of water shall in descending be pressed into a more slender sector than a drop of quicksilver, and consequently the earth shall more easily cast off any quantity of water than the same quantity of quicksilver. _B._ This one would think were true; as also that of simple fluid bodies, those whose smallest parts, naturally, without the force of fire, do strongliest cohere, are generally the heaviest. But why then should quicksilver be heavier than stone or steel? Fluidity and hardness are but degrees between greater fluidity and greater hardness. Therefore to the knowledge of what it is that causeth the difference, in different bodies, of their endeavour downward, there are required, if it can be known at all, a great many more experiments than have been yet made. It is not difficult to find why water is heavier than ice, or other body mixed of air and water. But to believe that all bodies are heavier or lighter according to the quantity of air within them, is very hard. _A._ I see by this, that the Creator of the world, as by his power he ordered it, so by his wisdom he provided it should be never disordered. Therefore leaving this question, I desire to know whether if a heavy body were as high as a fixed star, it would return to the earth. _B._ It is hard to try. But if there be this compounded motion in the great bodies so high, such as is in the earth, it is very likely that some heavy bodies will be carried to them. But we shall never know it till we be at the like height.