If wind is blown through the mouth of certain figures, they spout up water through some other place. For example, if a satyr holds a wine-skin, water shall be spouted up through the skin. A B C D (fig. 54), is an air-tight pedestal on which the figure is placed; through the mouth of the figure a tube, E F, is inserted, communicating with the pedestal, and having underneath it a small plate, G H, which closes the aperture F of the tube, and is supported by pins to which buttons are attached, that the plate may not fall off. Another tube, K L, is passed through the pedestal, of which the extremity, K, must be contiguous to the point at which the water-jet is to be, and the extremity, L, reach to the bottom of the pedestal, leaving only a passage for the water. At the extremity K there must be a valve or tap by which the aperture K, which is very small, may be shut. Now if we pour any quantity of water into the pedestal through a hole, which we must afterwards stop, and, having closed the aperture K, blow in air through the tube E F, the air blown in will thrust aside the plate and descend into the pedestal: and, if this is done several times, the air in the pedestal will be compressed and close the plate. Let the valve or tap be opened, and after a short time the compressed air will drive the liquid in the pedestal violently out through the aperture K, until all the liquid is spouted up, and the air is brought back to its natural state, that is, in which it is no longer subject to compression. 55. _A Vessel, out of which Water flows as it is poured in, but if the supply is withheld, Water will not flow again, until the Vessel is half filled; and on the supply being again stopped, it will not then flow until the Vessel is filled._ [Illustration: Diagram of apparatus as described in text]