Make a stand with a box upon it, having the roof and front of an ancient temple, the front of the stand being in steps leading up to the porch. This conceals a simple apparatus of glass tubes, receivers and siphons.
Fig. 104.
The four tubes are shown just above and below the bends, so as to appear to be solid glass pillars. The water from the upper reservoir fills them in running to find its level in the other container. Little figures are made of wax and pith, two having cork in their heads, two leaden feet, and they are placed in the tubes alternately. A valve below prevents them sinking, and a fine hair prevents them rising into the bends. On the water being let flow, the figures are imbued with motion, and their rising and falling will greatly puzzle the spectators, for the fluid is not seen to run.
Fig. 105.
Take two panes of common window-glass, about six inches square, set them together at one side, and at the other side prevent them exactly joining by a little wax, so that the two planes form a very small angle, as one or two degrees. Then place the bottom edge about an inch down into a dish of water, when the water will rise between the panes in the form of a hyperbola.
There is shown to the audience a singular instrument composed of glass, two bulbs connected by two tubes.
Fig. 106.
Water, which may be tinctured with indigo for the better effect, flows from the bulb A very slowly into the bulb B, whence it quickly and plainly runs up by the tortuous tubing, so thin as to scarcely let a hair pass through it back into the bulb A. The drops of ascending water are separated by air bubbles, so that the current can be clearly studied.
Now, though the laws of nature forbid that water can by any power in itself lift itself up to the height of the reservoir originally holding it, here seems a contradiction. For a time, friction and the resistance of the air appears to be done away with. But this paradox is readily accounted for after close watching.
It will be found that the descending liquid does not ascend from ball B into the winding tube without part of it being left in that ball. It is this filling the space which gradually forces the air upwards (since it cannot go down through the column of water from A). The only cause of the liquid rising beyond B is its being filled, and once it is full the movement must stop.
The same appearances of drops of water divided by air bubbles is shown in the windows of filter-dealers, who use great lengths of bent glass piping for the purpose of display; but a small force-pump is the active agent as regards their apparatus.
Full to the brim, without spilling one drop.—Take care that the edge of the glass is quite dry: pour the water into the glass gently, until it is quite full; then drop the shillings in one by one very gently, and on their edges. If you act otherwise, the water will run over the edge of the glass.
Shape out a doll, A B, of light material, and paint or dress him prettily, as your fancy suggests, and between his legs set the cone, C, made of thin sheet-copper.
Fig. 107.
On placing this aquatic Blondin on a perpendicular jet of water, it will balance itself on the top, while rising and falling divertingly.
A hollow copper ball, an inch in diameter, will balance itself in the like manner, turning continually round its centre, and casting the water from its surface.