be so carried out.

The pipe must in every case be made to enter the highest point of a
bubble in order to start an internal one. If it is pushed horizontally
through the side, the inner bubble is sure to break. If the inner bubble
is being blown with gas, it will soon tend to rise. The pipe must then
be turned over in such a manner that the inner bubble does not creep
along it, and so meet the outer one where penetrated by the pipe. A few
trials will show what is meant. The inner bubble may then be allowed to
rest against the top of the outer one while being enlarged. When it is
desired after withdrawing the pipe to blow more air or gas into either
the inner or the outer bubble, it is not safe after inserting the pipe
again to begin to blow at once; the film which is now stretched across
the mouth of the pipe will probably become a third bubble, and this,
under the circumstances, is almost certain to cause a failure. An
instantaneous withdrawal of the air destroys this film by drawing it
into the pipe. Air or gas may then be blown without danger.

If the same experiment is performed upon a light ring with cotton and
paper attached, the left hand will be occupied in holding this ring, and
then the gas must be controlled by the foot, or by a friend. The light
ring should be quite two inches in diameter. If, when the inner bubble
has begun to carry away the ring, &c., the paper is caught hold of, it
is possible, by a judicious pull, to cause the two bubbles to leave the
ring and so escape into the air one inside the other. For this purpose
the smallest ring that will carry the paper should be used. With larger
rings the same effect may be produced by inclining the ring, and so
allowing the outer bubble to peel off, or by placing the mouth of the
pipe against the ring and blowing a third bubble in real contact with
the ring and the outer bubble. This will assist the peeling process.

To blow three bubbles, one inside the other two, is more difficult. The
following plan I have found to be fairly certain. First blow above the
ring a bubble the size of a large orange. Then take a small ring about
an inch in diameter, with a straight wire coming down from one side to
act as a handle, and after wetting it with the solution, pass it
carefully up through the fixed ring so that the small ring is held well
inside the bubble. Now pass the pipe, freshly dipped in the solution,
into the outer or No. 1 bubble until it is quite close t