The Pneumatics of Hero of Alexandria

[it] is the weight of a coin of five drachme drachmas, or slightly less. For when such a coin is dropped through the mouth A of the vessel, it will fall onto the sphere R, and by weighing it down, it will make the lever O. P. tilt; consequently, the lid of the pile will be raised, which (once the coin has fallen) will drop to the bottom of the pile, and will cause the water to splash, which will no longer come out if the coin is not dropped through A again.

❦ PLACING VARIOUS TYPES OF WINE IN ONE VESSEL ❧
White, red, of many flavors, and water, to make them
come out of a single channel at our will.
Theor. XXII.

LET there be a vessel A.B., sealed and closed at the neck by the diafragrama diaphragm/partition C.D., which also has as many diaphragms or partitions throughout the height of the vessel as there are humors fluids you wish to put in said vessel, which are very well soldered into its body. And at the diaphragm C.D.—which, for easier understanding, we will say are two, namely E.F.—let it also be arranged that the diaphragm C.D. has as many holes as it can accommodate, like a sieve, dense and small, so that they lead through all the spaces between the partitions. And under the diaphragm let there be spiracoli vents/air-holes G.H.K. that pass to the parts where the humors are to be poured, from which let perforated pipes come out, soldered to said partitions, so that they all enter into a common channel R. But [they are] soldered to said partitions so that they do not mix the humors. For if you close the vents G.H.K. and the channel R, and by placing either water, or wine, or whichever sort of humor you like into the mouth of the vessel, it will not descend anywhere; because the air that is enclosed in them has no exit on any side. But, if you open one of said vents, immediately the water or wine that you have placed above in the mouth will enter the place where the breath air-flow is opened; but

A woodcut illustration shows a large, ornate vessel (labeled A and B) with internal tubes and chambers (labeled C, D, E, F, G, H, K, R). The vessel has a decorative spout, handle, and a base featuring a relief of a human face.

once the breath is closed and another vent is opened, another sort of humor placed therein will similarly descend into that part where the breath is opened. Wherefore, with all the vents and the holes of the sieve closed, even if you open the mouth of the channel R, nothing will come out if you do not open a vent for it, so that as air enters, the humor that is contained in that place will flow. Once this is closed and another similar one is opened, the same will happen, and so it will be for all the others.

❦ TWO VESSELS, WHICH ARE PLACED UPON THE SAME BASE ❧
one of which is full of wine and the other empty, and which
in proportion to how much water is placed in the empty one,
so much wine will come out of the other, are constructed
in this way. Theor. XXIII.

LET there be two vessels C.D. and E.F. upon a base A.B., which have their mouths closed with the diaphragms G.H.K.L., and let the tube or perforated pipe M.N.X.O. be placed in them and through the base, bent as the figure shows, the mouths of which should be a short distance from the diaphragms or partitions (which we shall call bottoms) G.H.K.O. And in the vessel E.F. let there be the bent pipe P.S., the curvature of

A woodcut illustration of two vessels on a single rectangular base (labeled A and B). On the left is a tall pitcher (C. D.). On the right is a spherical vessel (E. F.) with complex internal and external piping (labeled G, H, K, L, M, N, X, O, P, S, V, Y) and foliage motifs.

which should be at the mouth of the vessel, and its mouth P [should be] as far from the bottom as is necessary for the flow; but let the other leg protrude out of the vessel, formed into a channel. Let the infundibulo funnel Y then be passed through the diaphragm G.H., the mouth of which is soldered to the diaphragm and is a short distance from the bottom. Now let the vessel E.F. be filled through some hole, as for example V, which after it is almost completely full should be plugged; then, having placed water in the vessel C.D., it will push the air that is in it, and will