I have now blown an air-bubble on the fixed ring, and pushed up inside it a wire with a ring on the end. I shall now blow another air-bubble on this inner ring. The next bubble that I shall blow is one containing gas, and this is inside the other two, and when let go it rests against the top of the second bubble. I next make the second bubble a little lighter by blowing a little gas into it, and then make the outer one larger with air. I can now peel off the inner ring and take it away, leaving the two inner bubbles free, inside the outer one (Fig. 63). And now the multiple reflections of the brilliant colours of the different bubbles from one to the other, set off by the beautiful forms which the bubbles themselves assume, give to the whole a degree of symmetry and splendour which you may go far to see equalled in any other way. I have only to blow a fourth bubble in _real_ contact with the outer bubble and the ring, to enable it to peel off and float away with the other two inside. [Illustration: Fig. 63.] We have seen that bubbles and drops behave in very much the same way. Let us see if electricity will produce the same effect that it did on drops. You remember that a piece of electrified sealing-wax prevented a fountain of water from scattering, because where two drops met, instead of bouncing, they joined together. Now there are on these two rings bubbles which are just resting against one another, but not really touching (Fig. 64). The instant that I take out the sealing-wax you see they join together and become one (Fig. 65). Two soap-bubbles, therefore, enable us to detect electricity, even when present in minute quantity, just as two water fountains did. [Illustration: Fig. 64.] [Illustration: Fig. 65.] We can use a pair of bubbles to prove the truth of one of the well-known actions of electricity. Inside an electrical conductor it is impossible to feel any influence of electricity outside, however much there may be, or however near you go to the surface. Let us, therefore, take the two bubbles shown in Fig. 56, and bring an electrified stick of sealing-wax near. The outer bubble is a conductor; there is, therefore, no electrical action inside, and this you can see because, though the sealing-wax is so near the bubble that it pulls it all to one side, and though the inner one is so close to the outer one that you cannot see between them, yet the two bubbles remain separate. Had there been the slightest electrical influence inside, even to a depth of a hundred-thousandth of an inch, the two bubbles would have instantly come together. [Illustration: Fig. 66.]