35. A Vessel which will hold a certain quantity of Liquid when the supply is continuous, will only reccive a portion of such Liquid if the supply is intermittent.
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.