Nature of the motion of water.

e, K L, f t, S, a n, x, r, h, v

Nature of the movement of water.

d a, M, b, c, r

The vessel M has its water high from b up to a. And the pipe b a r c pours out of its mouth the water as high as the surface of the water of the vessel is; that is, the water that rises from c d is as much as the height b a in the vessel. And so, as that water a b lowers, so likewise lowers the water c d.

Water that, by cause of itself, raises itself above its own level. Let the reservoir a n be filled with water through the hole f. Then let that hole f be well stopped, so that water can no longer enter nor exit. Besides this, let the hole S be stopped, and then the vessel K L filled with water. Then let the hole S be unstopped, and the water of the vessel K L allowed to fall through the pipe S v into the vessel of air h. Which air, being pushed by the fall of the water, flees up through the pipe x t. Hence, entered by force into the vessel a n, it drives out of that vessel its water, which flees up through the pipe r e and leaps strongly on high until the water of the vessel K L has all descended into the vessel below, of air, h. And so it will go proportionally diminishing, as the fall of the water above diminishes.

Remember how the air compresses greatly in its receptacle before it has the power to drive the water out of its reservoir. The width of the pipe S v must be made equal to the width of the pipe t x. And the thickness of the pipe e r, in its upper part, must be more than 220 times smaller than the thickness of each of said pipes — that is, speaking of the diameter of the void of each. Then the water that descends through the pipe S v, exerting force of 200 ounces in its impact, or weight, upon all the walls of the vessel of air, and the hole of the pipe v entering 200 times into all the walls of that vessel of air, one ounce of power enters through the mouth of the pipe x t, which at once distributes itself among all the walls of the vessel a n. So that, we say, the hole of the pipe r e enters a thousand times, or occupies the thousandth part of all the walls of its vessel a n. Hence we shall say that, the force of the air driven in entering by the 200th part of the vessel a n, and the pipe r e occupying its thousandth part, there falls to that pipe 1/5 of an ounce of force, and the water that rises weighs 1/3 of an ounce.