24. _A Pipe from which flows Wine-and-Water in varying proportions._ [Illustration: Diagram of apparatus as described in text] Let there be an empty vessel, and another containing wine: whatever quantity of water we pour into the empty vessel, the same quantity of wine and water mixed may be drawn off through a pipe in any proportion we please; such, for instance, that there may be two parts of water to one of wine. Let A B (fig. 24) be an empty vessel, either a cylinder or a rectangular parallelopiped: by the side of this, and on the same base, place another vessel, C D, perfectly air-tight, and, like A B, either a cylinder or a rectangular parallelopiped; but the base of A B must be twice as great as that of C D, as the water is to be the double of the wine. Near C D place another air-tight vessel, E F, into which the wine is to be poured; and between the vessels C D, E F, let a tube run, G H K, perforating and soldered into their coverings. In E F let there be a bent siphon, L M N, the inner leg of which must reach almost to the bottom of the vessel, leaving only a passage for the water, and the other, being bent within the vessel, lead into the next vessel, O X. From this vessel let the tube P R lead through the vessels, or be carried under the pedestal on which they stand, that it may readily pass near the bottom of the vessel A B. Let another tube, T S, connect the vessels A B, C D, and near the bottom of A B place a small pipe, U, which with P R must be included in a larger pipe, Q W, provided with a cock by means of which it may be opened or shut at pleasure. When these preparations have been made, close the pipe Q W, and pour water into the vessel A B; a part, viz. one half, will pass into C D, through the tube S T, and the water which falls into C D will force out a mass of air equal to itself through G H K into the vessel E F; in like manner this air will force an equal quantity of wine into the vessel O X through L M N. Now, if we open the pipe Q W, the water poured into the vessel A B and the wine carried out of O X through the tube P R will flow through it together: and thus what was proposed will be done. The vessels will be empty again when, the mixed liquid having been all discharged, the air enters them through the tube P R. 25. _A Vessel from which Wine flows in proportion as Water is withdrawn._ [Illustration: Diagram of apparatus as described in text]