No. 58. A Vessel from which a Flow of Wine can be
stopped, by pouring into it a small Measure of Water.
IF there be a vessel full of wine and provided with a running spout, when a cyathus, or small measure, of water is poured upon the neck of the vessel, the discharge of wine shall cease, but, if a second measure of water poured on, this last shall flow out with the former, or the two measures of water shall flow out through two different spouts; and, after all the water is drawn off, the wine shall flow again from the centre spout: moreover, this shall happen as often as any liquid is poured on and flows out. Let A B (fig. 58), be a vessel with a spout, C, at the bottom, and closed at the neck by the partition D E from which extends a tube, F G, encircled by another tube which is sufficiently removed from the partition to allow of the passage of water, as in the case of the inclosed diabetes. Through the partition insert another tube, H K, projecting to a less height above the partition than the former tube, and branching off below into two spouts L and M ; and let this tube also be encircled by another tube distant a small space from the partition: furthermore let the vessel have a vent N just under the partition. Now, if, after closing the spouts, we pour in the wine, it will pass into the body of the vessel through the tube F G, for the air will escape through the vent N: but when we close the vent and set the spouts free, the liquid intercepted in the tube H K will flow through L and M, and that contained in the vessel through C. If, however, while C is still running, we pour a small measure of water upon the partition, the air will no longer be able to enter through F G, and the discharge through C will cease: but if a second measure is poured on, the water will rise above the tube H K, and be carried through into the spouts L and M, the whole being drawn up; and then, the tube F G being opened to the air will enable the spout C to flow as before. This result will take place as often as we pour on the measures of water.