Magic Fountain
Take a tall glass tube, hermetically sealed both at top and bottom, by
means of a brass cap screwed on to a stop-cock, and place it on the
plate of the pump. When the air is exhausted, turn the cock, take the
tube off the plate, and plunge it into a basin of mercury or water.
Then the cock being again turned, the fluid, by the pressure of the
air, will play upon the tube in the form of a beautiful fountain.