Soap Bubbles
and the Forces which Mould Them

THE FORCES WHICH MOULD THEM. Ijjl and so it will presently appear again, having bounced out of the liquid. As it falls it will be seen to vibrate as the result of the sudden release from the one-sided pull. The neck which was drawn out will meanwhile have gathered itself in the form of a little drop, which will then be violently hit by the oscillations of the remaining pendant drop above, and driven down. The pendant drop will be seen to vibrate and grow at the same time, until it again breaks away as before, and so the phenomena are repeated. In order to perfectly reproduce the experi- ment, the axle should be firmly held upon a stand, and the speed should not exceed one turn in two seconds. The effect is still more real if a screen is placed between the disc and the mirror, which will only allow one of the drops to be seen. Water-drops in Paraffin and Bisulphide of Carbon. All that was said in describing the Plateau experiment applies here. Perfectly spherical and large drops of water can be formed in a