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The pneumatics of Hero of Alexandria

Chapter 70: 66. Wine discharged into a Cup in any required quantity.
By of Alexandria Hero
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About This Book

A systematic practical handbook of machines and demonstrations that uses air, steam, heat, and water to produce mechanical effects. The text gives clear descriptions, construction details, and diagrams for siphons, valves, pumps, fountains, jets, self‑acting mechanisms, and ritual or theatrical contrivances driven by pressure and temperature changes. Explanations focus on the mechanical principles behind pneumatic and hydraulic behaviors and on ways to control flow and timing, with numbered propositions that pair instructional steps with illustrative figures for building and operating each apparatus.

66. Wine discharged into a Cup in any required quantity.

Let there be a vessel filled with wine and provided with a spout under which a drinking cup is placed: wine shall run into the cup in any required quantity. Let A B (fig. 66), be the vessel containing wine, and C D the spout, the upper surface of which at the extremity C is so smooth that, when a valve in the form of a kettle-drum E F is placed upon it, water is excluded. On the handle of the vessel fix the vertical rod G H, on which, as on a fulcrum, another rod K L vibrates: again place another rod, M N, under the pedestal, moving about the point X, and attach two more rods K O, L P, moving on pivots in such a way that, if the extremity M of the bar be depressed, the valve E F is raised, and the spout is opened and sends out a stream, but is closed again when M is suffered to return. Let the bar M N support the drinking cup R, into which we wish to receive the given quantity of liquid: the cup must be placed beneath the spout. Take a weight, S, capable, by means of a ring, of being shifted along the projection M O of the rod: and when S has been brought towards M, the spout will be opened and send its stream into the cup, but as the cup grows heavy the weight will be raised again and the spout closed. That the wine may flow out in the required quantity, place in the cup any measure of liquid, for instance, a cotyle, and, receiving what falls from the spout in another vessel, shift the weight along the bar to the first point at which the discharge from the spout ceases: make a mark on the bar at this point and register one cotyle. We must proceed in the same manner for a half-cotyle, and two cotylæ, and so on for other measures as far as we please; and thus we shall have marks for the different quantities, signifying the points to which the weight must be brought in order that they may be discharged. Instead of the valve E F, an air-tight vessel may encircle the spout, so that, as long as the liquid is kept away by the air within, there will be no discharge through the spout.