WATER IN PERPETUAL MOTION.
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.