THE PNEUMATIC DANCER.
This amusing pneumatic toy consists of a figure made of glass or enamel, and so constructed as to remain suspended in a glass jar of water. An air-bubble, communicating with the water, is placed in some part of the figure, shown at m, near the top of the jar, A, in the engraving. At the bottom, B, of the vessel is a bladder, which can be pressed upwards by applying the finger to the extremity of a lever, e o, when the pressure will be communicated through the water to the bubble of air, which is thus compressed. The figure will then sink to the bottom; but, by removing the pressure, the figure will again rise, so that it may be made to dance in the vessel, as if by magic. Fishes, made of glass, are sometimes substituted for the human figure. A common glass jar may be used for this experiment, in which case the pressure should be applied to the upper surface, which should be a piece of bladder, instead of being placed at the bottom, as shown in the figure engraved.