<h2><SPAN name="CHAPTER_XII" id="CHAPTER_XII"></SPAN>CHAPTER XII</h2>
<h2>OUR HEAVIEST DUTIES</h2>
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<div><span class="pagenum"><SPAN name="Page_116" id="Page_116"></SPAN></span></div>
<h3><i>THE SCRIBE'S NOTE ON CHAPTER TWELVE</i></h3>
<div class="blockquot"><p>Here the electron explains its behaviour
in a dynamo at work.</p>
<p>The principle of the dynamo was discovered
by Faraday in the thirties of last century.</p>
<p>He found that when a coil of wire was
moved through a magnetic field, there was a
current of electricity induced in the moving
coil.</p>
<p>Experimental machines were constructed,
and after a while a practical dynamo was
evolved.</p>
<p>Wires are attached to a dynamo and the
electric current is led out.</p>
<p>This current may be conducted to a distant
tramway car, and, by sending the current
through an electric motor, mechanical motion
is produced and the car propelled along.</p>
<p>An electric motor is practically the same
as a dynamo, but instead of turning its coil
round in order to produce an electric current,
we pass a current into the coil and it moves
round. It will be sufficient to leave the
electron to tell its own story.</p>
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<p><span class="pagenum"><SPAN name="Page_117" id="Page_117"></SPAN></span>
This is another of those roving commissions
in which I have been privileged to take part
on more than one occasion.</p>
<p>If you think of the giant size of an electric
tramway car or a railway train, and try to
compare one of these with an electron, such
as your humble servant, it will seem quite
ridiculous that I should suggest that it is
we electrons who move those huge vehicles.
Yet such is the actual case.</p>
<p>Of course we require the application of
very considerable power to urge us to so
heavy a task. All the energy which we can
get from a few electric batteries might enable
us to drive a toy car, but when it comes to
turning the wheels of a real car or train, we
require a correspondingly greater amount of
energy.</p>
<p>I may as well tell you quite frankly that
<span class="pagenum"><SPAN name="Page_118" id="Page_118"></SPAN></span>
we electrons are only the intermediaries or
go-betweens. Indeed, you must have noticed
that in every case we act merely as a connecting
link between matter and the æther, and
between the æther and matter.</p>
<p>But what I want to tell you of, is the part
we play in moving an electric car or railway
train. It is really all very simple if you could
only see it from our standpoint. Picture a
host of us attached to copper atoms in a coil
of wire which is being moved through that
disturbed æther called a <i>magnetic field</i>. We
are set in motion immediately. It is true
that when we are moved forward into the
field we march off in one direction, only to
be arrested and made to move off in the
opposite direction as we leave the field, but
it really makes no difference in our working
capabilities as long as we are kept on the
move. This is what is actually taking place
in the armature of a dynamo as it revolves
between the poles of the electro-magnet.
There is no peace for us so long as the coil
is kept revolving; we are kept in a constant
state of rapid to-and-fro motion.</p>
<div class="figcenter"> <span class="pagenum"><SPAN name="Page_119" id="Page_119"></SPAN></span> <SPAN href="images/figp119-800.jpg"> <ANTIMG src="images/figp119-400.jpg" width-obs="306" height-obs="400" alt="" title="" /></SPAN> <p><small><i>By permission of Siemens Schuckert Werke</i> <span class="ralign"><i>Berlin</i></span></small></p>
<p class="smcap bold center">A Train Impelled by Moving Electrons</p>
<p>It is remarkable that the motion of electrons in an electric
conductor can result in the movement of heavy vehicles. How this
comes about is explained in <SPAN href="#CHAPTER_XII">Chapter XII</SPAN>.</p>
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<p>This is all we electrons do in a dynamo,
but when the ends of the outer circuit or
<span class="pagenum"><SPAN name="Page_121" id="Page_121"></SPAN></span>
mains are brought into contact with the
ends of our revolving coil, we set the electrons
in the mains surging to and fro in step with
ourselves. Man describes this motion of the
electrons in the mains as an <i>alternating electric
current</i>, but by a simple commutator on the
dynamo he may arrange that we set the
electrons marching in one direction in the
mains. This he describes as a <i>direct electric
current</i>.</p>
<p>It is a matter of indifference to us whether
man drives our coil round by means of a
steam-engine, a water-wheel, or a wind-mill;
all that we electrons want is to be kept
surging or vibrating to and fro. Now you
will be able to appreciate how we electrons
get up sufficient motion to enable us to perform
what I have described as <i>our heaviest
duties</i>.</p>
<p>Perhaps you will find it difficult to believe
me when I tell you that as we march along
the connecting wire to a distant tramway
car we transmit the energy through the
surrounding æther, and not through the
wire. This is our mode of working in every
case, whether it be an electric bell, a telegraph,
or telephone. That is to say, while
<span class="pagenum"><SPAN name="Page_122" id="Page_122"></SPAN></span>
we electrons move from atom to atom in
the connecting wire, it is the disturbed
æther surrounding us which transmits the
energy. You must have realised by this
time how very intimate is the relationship
between ourselves and the æther.</p>
<p>To return to the tale of our tramway work,
you will picture my fellow-electrons aboard
the car being energised by the incoming
current. Those electrons present in the
armature coil of the motor are set into
motion, as also are those in the wire of the
neighbouring electro-magnet. The result is
that these two sets of electrons so disturb
the æther and affect one another that the
coil is moved round into a different position.
You will remember the experiment of which
I told you, in which a magnetic needle would
insist always in taking up a position at right
angles to a wire in which an electric current
is passing. Well, when the motor coil has
turned into its new position, we electrons
receive an impulse from our friends in the
line-wire which causes us to retrace our steps
in the coil. This action of ours causes the
coil to make a further movement in the
same direction as at first. Again we change
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our direction of march, and again the coil
changes its position towards the electro-magnet.
The sole duty of these electrons in
the armature coil is to keep surging to and
fro, while those electrons in the electro-magnet
keep up a steady march in one direction.
This arrangement necessitates the
armature coil to keep changing its position
continually, and when we have the armature
coil spinning round at a steady pace, it is
easy for man to connect the armature to
the axles of the tramway car and cause us
to drive the wheels round.</p>
<p>I need hardly say that it makes no difference
to us whether we are asked to drive a tramway
car, a railway train, or a host of machines
in a factory or workshop. All that we
electrons in the motor require is to have
sufficient energy passed along to us from our
fellows in the distant dynamo. Again I
admit frankly that the atoms of matter play
a very important part in these our heaviest
duties, but you will see that without our
active assistance they could not transmit the
necessary energy to a distant car or train.</p>
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