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. 67. _A Goblet into which as much Wine flows as is taken out._ [Illustration: Diagram of apparatus as described in text] Let there be a vessel containing wine and provided with a spout, underneath which a goblet is placed: whatever quantity of wine is taken from the goblet, as much shall flow into it from the spout. Let A B (fig. 67), be the vessel of wine, and C D the spout, to which are attached the valve E F, and the rods G H, K L, K O, L M as before; and beneath the spout place the cup P. To the rod K O fix a small basin R contained in the vessel S T, and let a tube, U Q, connect the vessels S T and P. When these arrangements are complete, if the vessels S T and P are empty, the basin R will fall to the bottom of S T, and open the spout C D. A stream will flow from C D into both the vessels S T and P, so that the basin will rise and shut the spout again, until we remove more liquid from the goblet. This result will happen as often as we remove liquid from P.