<h2><SPAN name="CHAPTER_XX" id="CHAPTER_XX"></SPAN>CHAPTER XX</h2>
<h2>CONCLUSION</h2>
<hr class="tb" />
<div><span class="pagenum"><SPAN name="Page_194" id="Page_194"></SPAN></span></div>
<h3><i>THE SCRIBE'S NOTE ON CHAPTER TWENTY</i></h3>
<div class="blockquot"><p>Not many of us have realised the true importance
of electrons in the Creator's plans.</p>
<p>In the following short chapter the electron
is made to sum up a few of the wonders
which it has related, in order to focus our
attention upon the grand place which the
electrons occupy in the universe.</p>
</div>
<hr class="tb" />
<p><span class="pagenum"><SPAN name="Page_195" id="Page_195"></SPAN></span>
From what I have told you of myself and my
fellow-electrons, it must be apparent that
we are of tremendous importance to man.
I have told you something of the part we
played in building up this world—how we
not only form the atoms of matter, but also
hold these bricks of the universe together.
I have given you a rough sketch of the composition
of these bricks.</p>
<p>You must have realised also that without
us the whole universe would be in darkness.
There would be no light, no heat, and consequently
no life. Indeed, there could be no
material existence without us.</p>
<p>Where would man be if we failed to perform
our mission? He could not exist if we
even neglected a few of our duties. Not only
do we form the atoms of which his body
<span class="pagenum"><SPAN name="Page_196" id="Page_196"></SPAN></span>
is composed, also holding these together, but
we produce all those chemical changes within
his body which are absolutely necessary to
maintain life. His very thoughts are dependent
upon our activities.</p>
<p>I have told you how we send man's messages
across the earth, and how we transmit power
from place to place. Also how we have enabled
man to gain knowledge of the distant
stars, and to examine the bones of his living
body.</p>
<p>If man could cross-examine me or any of
my fellows, I expect the first question would
be—What are you electrons made of? But
man must find this out for himself. The
Creator has placed man in a world full of
activity, and it is of intense interest to man
to discover the meaning of all that lies around
him. That is why I have been bound over
by my fellows to tell you only so much of
our history as man has discovered. But I
am disclosing no secret when I admit that
our very existence as electrons is dependent
upon the æther.</p>
<p>If I can find another scribe to write a
re<span class="pagenum"><SPAN name="Page_197" id="Page_197"></SPAN></span>vised
biography for me a few hundred years
hence, I shall have a much more interesting
tale to tell, for many of our doings, of which
man knows nothing at present, will be secrets
no longer by that time.</p>
<hr class="cb" />
<div><span class="pagenum"><SPAN name="Page_199" id="Page_199"></SPAN></span></div>
<h2><SPAN name="APPENDIX" id="APPENDIX"></SPAN>APPENDIX</h2>
<hr class="tb" />
<div><span class="pagenum"><SPAN name="Page_200" id="Page_200"></SPAN></span></div>
<h3><i>THE SCRIBE'S NOTE ON APPENDIX</i></h3>
<div class="blockquot"><p>As explained by the author in
<SPAN href="#CHAPTER_I">Chapter I.</SPAN>,
this appendix has been added for the sake of
those readers who may wish further details
than have been given in the electron's story.</p>
<p>It is only necessary to give a brief notice of
the more important particulars, as the author
has written recently upon this subject in a
popular form.<SPAN name="FNanchor_1_1" id="FNanchor_1_1"></SPAN><SPAN href="#Footnote_1_1" class="fnanchor">[1]</SPAN></p>
</div>
<div class="footnote"><p>
<SPAN name="Footnote_1_1" id="Footnote_1_1"></SPAN><SPAN href="#FNanchor_1_1">
<span class="label">[1]</span></SPAN> "Scientific Ideas of To-day."
By Chas. R. Gibson, F.R.S.E. (London: Seeley & Co., Ltd. Five
shillings net.)</p>
</div>
<hr class="tb" />
<p><span class="pagenum"><SPAN name="Page_201" id="Page_201"></SPAN></span>
It was known two thousand years ago that
when a piece of amber was rubbed with a
woollen cloth, the amber would attract light
objects towards it. Amber was considered to
be unique in this respect.</p>
<p>About the year 1600, one of Queen Elizabeth's
physicians, Dr. William Gilbert, inquired
into this attractive property of amber.
He found that many other substances possessed
the same property. Indeed it is
common to all substances in some degree.
We say the amber or other object is "electrified."</p>
<p>It was observed by the early experimenters
that there were two kinds of electrification.
To one of these they gave the name <i>positive
electricity</i>, and to the other <i>negative electricity</i>.</p>
<p>Every electrified object will attract an
ob<span class="pagenum"><SPAN name="Page_202" id="Page_202"></SPAN></span>ject
which is not electrified, and two objects
which are oppositely electrified will attract
one another also. But two objects which are
similarly electrified will repel each other.</p>
<p>Man got tired of rubbing objects by hand,
so he fitted up simple machines in which glass
cylinders or plates were rubbed against
leather cushions. The electricity was then
collected by little metal points supported on
an insulated metal sphere.</p>
<p>The experiment of attempting to store
electricity in a glass vessel filled with water
was made at the University of Leyden
(Netherlands). The water was replaced later
by a coating of tin-foil on the inner surface,
while a similar metallic coating on the outside
took the place of the experimenter's hand.
These jars are called <i>Leyden jars</i>, after the
place in which the discovery was made.</p>
<p>About 1790, Professor Galvani, of Italy,
observed that the legs of a freshly killed frog
twitched at each discharge of an electrical
machine. Later he found that the same
twitching occurred when he connected certain
<span class="pagenum"><SPAN name="Page_203" id="Page_203"></SPAN></span>
parts with a piece of copper and zinc. He
believed this to be due to "animal electricity"
secreted within the frog.</p>
<p>Professor Volta, also of Italy, proved that
Galvani's idea was wrong, and that the electricity
resided in the metals rather than in the
frog. He showed that when two pieces of
dissimilar metal were put in contact with one
another, there was a slight transference of
electricity between them. He constructed a
pile of copper and zinc discs, with a moist
cloth between each pair or couple, and by
connecting wires from the top copper disc to
the lowest zinc disc he was able to show that
an appreciable current of electricity was produced.
Later he placed a piece of copper and
a piece of zinc in a vessel containing acidulated
water, whereupon he found that a steady
current of electricity was obtained. This was
the invention of electric batteries.</p>
<p>The phenomena of <i>magnetism</i> were known
to the ancients, but it was not until the nineteenth
century that we found any real
connection between electricity and magnetism.
In 1819, a Danish philosopher, Hans
<span class="pagenum"><SPAN name="Page_204" id="Page_204"></SPAN></span>
Christian Oersted, discovered that an electric
current passing in a wire affected a magnet in
its neighbourhood. If the magnet was supported
on a pivot, after the manner of a
compass needle, it would turn round and take
up a position at right angles to the wire
carrying the electric current.</p>
<p>The molecular theory of magnetism presumes
that every molecule of iron is a tiny
magnet, having a north and south pole. In
a piece of unmagnetised iron, these tiny
magnets are all lying so that they neutralise
one another. When they are turned round
so that their north poles are all lying in one
direction, then the iron is said to be magnetised.</p>
<p>The electron theory of magnetism does not
do away with the older molecular theory just
referred to. The electron theory goes a step
farther, and tells us that these molecules are
magnets because of a steady motion of electrons
around the atoms of iron.</p>
<p>It was discovered in 1825 that when an
electric current was sent through an insulated
<span class="pagenum"><SPAN name="Page_205" id="Page_205"></SPAN></span>
wire wound around a piece of soft iron, the
iron became a magnet; when the current was
stopped the magnetism disappeared. Such
magnets are called <i>electro-magnets</i>. If a piece
of hard steel is treated in the same way it
becomes a <i>permanent magnet</i>. It was this
intimate connection between electricity and
magnetism, or, in other words, the invention
of these electro-magnets, which brought us
electric bells, telegraphs, telephones, dynamos,
and electric motors.</p>
<p>It should be noted that while iron is
attracted by either pole of a magnet, there
is such a thing as magnetic repulsion. This,
however, takes place only between two magnets,
and then only between like poles.</p>
<hr class="tb" />
<p>Some German physicists made a number of
electrical experiments with vacuum tubes.
When Sir William Crookes (England) was
experimenting with similar vacuum tubes he
suggested that matter was in a "radiant"
state during the electric discharge within the
tubes.</p>
<p><span class="pagenum"><SPAN name="Page_206" id="Page_206"></SPAN></span>
In 1880, H. A. Lorentz, of Amsterdam,
declared that light was due to the motion
of small particles revolving around the atoms
of matter.</p>
<p>Professor Zeeman, of Holland, produced
experimental proof of Lorentz's theory. He
showed that the revolving "particles" were
influenced by a powerful magnetic field, in the
manner explained in the electron's story.
This discovery was made in 1896, or sixteen
years after Lorentz's declaration. It was
Dr. Johnstone Stoney, of Dublin University
(Ireland), who christened these particles
"electrons."</p>
<p>The X-rays were observed for the first time
by Professor Roentgen, of Germany, in 1895.
The screens used for viewing the luminous
effects produced by the X-rays are coated
with very fine crystals of <i>barium platinocyanide</i>.
These screens were in use for
another purpose previous to the discovery
of X-rays.</p>
<p>We know now that <i>chemical affinity</i> is
merely electrical attraction between the atoms
of matter.</p>
<p><span class="pagenum"><SPAN name="Page_207" id="Page_207"></SPAN></span>
The spectroscope consists of a glass prism,
or series of prisms, mounted between two
metal tubes. One tube is provided at one
end with a vertical slit, through which the
light that is to be examined is passed. At
the other end of the tube is a lens, so that
the beam of light from the slit emerges
through the lens as a pencil of parallel rays.
The pencil of light then falls upon the glass
prism, striking it at an angle. In passing
through the prism, the light is bent round
so that it enters the second tube, which is
simply a small telescope. The prism separates
the æther waves according to their wave-lengths,
and produces the well-known coloured
spectrum, which is magnified by the telescope.
The reason for the bending of the different
waves is explained in the electron's story.</p>
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