<h2><SPAN name="CHAPTER_I" id="CHAPTER_I"></SPAN>CHAPTER I</h2>
<h2>WHAT THE STORY IS ABOUT</h2>
<hr class="tb" />
<p>The reason for writing this story is given
in the Preface, but the title is so strange
that the reader will wish naturally to know
what the story is about. What is an electron?
Is it an imaginary thing, or is it a
reality?</p>
<p>One of the reasons for writing this story
in its present form is to help the reader to
realise that electrons are not mythical, but
real existing things, and by far the most
interesting things we know anything about.
The discovery of electrons has shed a new
light upon the meaning of very many things
which have been puzzles until now. They
give us a reasonable explanation of the cause
of light and colour. They provide a new idea
of the constitution of matter. They enable
us to picture an electric current, and they
give us definite, though by no means final,
<span class="pagenum"><SPAN name="Page_22" id="Page_22"></SPAN></span>
answers to the why and wherefore of magnetism,
chemical union, and radio-activity.</p>
<p>The story is imaginary only in so far that
one of the electrons itself is supposed to tell
the tale. But in the endeavour to make
the story interesting, there has been no
sacrifice of accuracy in the statements of
fact.</p>
<p>While all names and dates, and many other
details, have been kept out rigidly from the
story, a note of the more important of these
has been added in an Appendix for the sake
of those readers who may wish to refer to
them.</p>
<p>It will be well to introduce the electron to
the reader before leaving it to speak for
itself. We have definite experimental proof
of the existence of electrons, and yet it is
very difficult to realise their existence, for
two reasons. In the first place, they are so
infinitesimally small. We count a microbe a
small thing; we can see it only with the aid
of a very powerful microscope. Yet that
little speck of matter contains myriads of
particles or <i>atoms</i>. An atom of matter is
therefore an inconceivably little thing, but
even that is a great giant compared to an
elec<span class="pagenum"><SPAN name="Page_23" id="Page_23"></SPAN></span>tron.
Our second difficulty in realising the
existence of an electron is that it is not any
form of what we call <i>matter</i>; it is a particle of
<i>electricity</i>, whatever that may be.</p>
<p>From the earliest experiments it became
evident that there were two distinct kinds of
electricity. These were described by the
pioneer workers as <i>positive</i> and <i>negative</i>
electricities. To-day we have definite experimental
proof that negative electricity is
composed of separate particles or units. Just
as matter is composed of invisible atoms, so
also is negative electricity of an atomic
nature. These particles of negative electricity
have been christened electrons, <i>electron</i>
being the Greek word for <i>amber</i>, from which
man first obtained electricity. Of course no
one can ever hope to see an electron, but
physicists have been able to determine its
size and <i>mass</i>, its electric charge, and the
speeds at which it moves.</p>
<p>While it has been known for more than
a century that <i>light</i> is merely waves in the
all-pervading æther of space, set up by incandescent
bodies, it has been a puzzle always
how matter could cause waves in the æther, as
it offers no resistance to the movement of
<span class="pagenum"><SPAN name="Page_24" id="Page_24"></SPAN></span>
matter through it. Here we are on the back
of a great planet, flying through space at
the enormous rate of one thousand miles per
minute, and yet our flimsy atmospheric
blanket is in no way disturbed by the æther
through which we are flying. In the following
story we shall see that these electrons
help us towards a solution of this and many
other problems; they provide the missing link
between matter and the æther.</p>
<p>But what is this <i>æther</i> of which one hears
so much in these days? The truth is we know
nothing of its nature. We cannot say whether
it is lighter than the lightest gas or denser
than the densest solid. The æther, whatever
it may be, is as real as the air we breathe. It
is the medium which brings us light and heat
from the sun, and which carries our wireless
telegraph and telephone messages. The
whole universe is moving in this great æther
ocean.</p>
<p>In order to make the electron's story
perfectly intelligible to every reader, I have
added a short explanatory note at the beginning
of each chapter. These notes merely
state the facts about which the electron is
speaking.</p>
<p><span class="pagenum"><SPAN name="Page_25" id="Page_25"></SPAN></span>
To make the electron's story as realistic as
possible, it has been necessary to give the
imaginary electron perfect freedom of knowledge
concerning itself and its surroundings.
In our schooldays we had to write the
autobiographies of steel pens, and such-like,
but these inanimate things had to be endowed
with powers of thought, feeling, and desire.
It is very important, however, to remember
that an electron is a particle of negative
electricity—<i>a real existing thing</i>.</p>
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