No. 51. A Vessel from which flowing Water may be stopped at pleasure.
IF a bowl stands upon a pedestal and has an open waterspout, the discharge shall suddenly cease, though there be no slide or tap attached to shut the spout. Let A B (fig. 51), be the bowl on the pedestal C: through the bottom of the bowl and the pedestal insert a tube, D E F, terminating in a spout; and at the handle of the vessel fix a bar, G H, against which another bar, K L, may move about the pin H: at the extremity K place a vertical bar, K M, moving about the pin K: to this bar let a box, N X, be attached at M, having weight, and large enough to inclose the tube D E F. When the bowl is full, if we depress the extremity L of the bar, the box N X will ascend, and, when this is raised, the water in the bowl will be carried out through the tube D E F: but if the extremity L be set free, the box will descend and encompass the tube D E F, and the air it contains, having no way of escape, will disconnect the liquid round the tube D E F, and prevent it from being further carried out through the mouth D. When we again depress the extremity L the spout will run as before.