42. A Water Jet actuated by compressed Air from the Lungs.
There are vessels from which water is forced up by blowing into them. Through the neck of the vessel (fig. 42), a tube is inserted, reaching nearly to the bottom, and soldered in at its mouth. Stop this mouth with the finger, and pour in some liquid through a hole: then, having blown into the vessel through the same hole, close it by means of a key, and set free the mouth of the tube; the liquid will be made to spout up through the orifice by the compressed air which was blown in.