A vessel can be made which, as long as you pour in any liquid, admits it, but, if you once cease pouring, holds no more: the construction is in this manner. Let A B (fig. 35), be a vessel, the neck of which is closed by the partition C D. Through the partition insert the tube E F, reaching nearly to the bottom, and projecting above the partition so as almost to reach the brim of the vessel; and let this tube be encircled by another G H, the top of which is closed by a lid, at a sufficient interval from the partition and the tube E F to admit of the passage of water: in A B make an air-hole, K, leading into the body of the vessel. Now, if we pour liquid into the vessel’s neck, it will be found that it will pass into the body through the tubes G H and E F, the air retreating through the vent K. But, if we cease pouring, and the neck of the vessel becomes empty, the air will break the continuity, so that any liquid in G H will flow down and fall upon the partition; for the breadth about the tube G H should be considerable, that the water may fall by its own weight. If more liquid be poured in, the air confined in the tubes E F and G H will not allow it to pass through, so that it will run over the brim of the vessel. 36. _A Satyr pouring Water from a Wine-skin into a full Washing-Basin, without making the contents overflow._ [Illustration: Diagram of apparatus as described in text] Construct on a pedestal the figure of a satyr holding in his hands a wine-skin: place near a washing-basin, and into this let some liquid be poured until it is full; water shall be made to flow into the basin without running over, until all the water in the skin is exhausted. The following is the construction. Let A B (fig. 36), be a perfectly air-tight pedestal, either cylindrical or octagonal in shape, as may seem more elegant, and divided into two chambers by the partition C D, through which the tube E F, fitting closely into the partition, extends upwards nearly to the roof of the pedestal. Through the roof insert the tube G H, projecting slightly above the vessel, and lying exactly under the basin, while, below, it reaches to the bottom except that room must be left for the passage of water: this tube must be soldered into the roof of the pedestal and the partition. Another tube, K L M, must also be inserted through the roof, reaching not quite so low as the partition, soldered into the roof and carrying its stream into the basin, which lies above the tube G H and communicates with it. Now let the vessel A D be filled with water through an orifice N, which must be afterwards closed. If water is poured into the basin, it will pass through the tube G H into the vessel B C; and the air in B C, passing through the tube E F and into the vessel A D, will force the liquid in A D through K L M into the basin; and this being carried again into B C will force out the contained air as before, which, again, will force