OF HERO

B 2

be a vacuumoriginal: "vacuo"; refers to the lack of air that allows the siphon to function: because, if the water must come out, it is necessary that the upper part of the pipe first fills, into which air cannot enter by any means. Wherefore, if we pierceoriginal: "pertugiaremo"; to make a small hole or aperture it in the upper part, the water will immediately come out, and in its place the air will succeed: but before said hole is made, the moisture—that is, the water that is in the pipe—strikes against the subject air, which, having no place where it can flow, does not let the water out: but when, by means of the hole, the air finds a place, then it gives way to the water and lets it flow out, filling its place. And for this reason, against naturemeaning against the natural downward tendency of heavy elements like water, one draws the wine through the pipe with the mouth: because by drawing the air that is in the pipe, one comes

A geometric diagram showing three concentric circles with a common center marked G. A vertical line connects the center G to point B on the top of the outermost circle. A horizontal line passes through the center, marking point D and C on the left circles, and point F on the right. Point A is marked on the right side of the outermost circle.

to fill it much more, and by being joined to this air, we come to detach it. And this is done until, with the surface of the wine—as was said above—the evacuation is made, so that then the detached wine, flowing, falls into the evacuated place of the Tube, having no other place in which it is permitted to flow, and for this reason it is carried upwards against nature. Otherwise, the water in the pipe will come to rest when it is settled in a spherical surface, the center of which is the same as the center of the earth. For if there is any surface of water that has the same

center as the earth, it remains still: but if it is possible that it does not remain still, it must be that by moving, it comes to rest. Let it be then, that the center of its spherical surface, being the same as that of the earth, follows the first surface: For water, flowing here and there through one and through many places, will have occupied different places; let it be, therefore, that each of those surfaces which have their center with the earth are cut by some plane, and by them lines are created in said surfaces, which are circles of the circumferences that have the same center as the earth, namely A.B.C.F. B.D. and let B.G. be drawn, which, because it will be equal to each of them—namely G.F. and G.A.—as is possible, it is therefore necessary that it comes to rest, and let so much be said of this.

ON THE PNEUMATIC TUBE IN THE MIDDLE OF ANOTHER

There is another sort of pipe or Tube, which is called a middle pneumaticoriginal: "Spiritale"; from the Greek "pneumatikos," relating to air, breath, or pressure tube, for which the reasoning is the same as the past one of the bent pipe. Let the vessel full of water be A.B., in the middle of which is placed the Tube C.D., which, passing through the foot of said vessel, extends below it: but in the upper part, its mouth does not reach the mouth of the vessel A.B., but is surrounded by another Tube, the void of