o apparatus beyond a few
pieces of glass or india-rubber pipe, or other simple things easily
obtained are required. If they will take this trouble they will find
themselves well repaid, and if instead of being discouraged by a few
failures they will persevere with the best means at their disposal, they
will soon find more to interest them in experiments in which they only
succeed after a little trouble than in those which go all right at
once. Some are so simple that no help can be wanted, while some will
probably be too difficult, even with assistance; but to encourage those
who wish to see for themselves the experiments that I have described, I
have given such hints at the end of the book as I thought would be most
useful.

I have freely made use of the published work of many distinguished men,
among whom I may mention Savart, Plateau, Clerk Maxwell, Sir William
Thomson, Lord Rayleigh, Mr. Chichester Bell, and Prof. Rucker. The
experiments have mostly been described by them, some have been taken
from journals, and I have devised or arranged a few. I am also indebted
to Prof. Rucker for the use of various pieces of apparatus which had
been prepared for his lectures.

SOAP-BUBBLES, AND THE FORCES WHICH MOULD THEM.

I do not suppose that there is any one in this room who has not
occasionally blown a common soap-bubble, and while admiring the
perfection of its form, and the marvellous brilliancy of its colours,
wondered how it is that such a magnificent object can be so easily
produced.

I hope that none of you are yet tired of playing with bubbles, because,
as I hope we shall see during the week, there is more in a common bubble
than those who have only played with them generally imagine.

The wonder and admiration so beautifully portrayed by Millais in a
picture, copies of which, thanks to modern advertising enterprise, some
of you may possibly have seen, will, I hope, in no way fall away in
consequence of these lectures; I think you will find that it will grow
as your knowledge of the subject increases. You may be interested to
hear that we are not the only juveniles who have played with bubbles.
Ages ago children did the same, and though no mention of this is made by
any of the classical authors, we know that they did, because there is an
Etruscan vase in the Louvre in Paris of the greatest antiquity, on which
children are represented blowing bubbles with a pipe. There is however,
no means of telling now