<h2><SPAN name="CHAPTER_XVI" id="CHAPTER_XVI"></SPAN>CHAPTER XVI</h2>
<h2>HOW MAN PROVED OUR EXISTENCE</h2>
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<h3><i>THE SCRIBE'S NOTE ON CHAPTER SIXTEEN</i></h3>
<div class="blockquot"><p>Several men of note declared that "little
particles" revolved around the atoms of
matter, and that it was the motion of these
particles which produced the well-known
æther waves of light.</p>
<p>This idea was suggested by the result of
certain mathematical calculations.</p>
<p>It was some time before real experimental
proof was obtained.</p>
<p>The electron tells its own tale of this
great discovery.</p>
<p>When the electron speaks of a spectrum
line being shifted up or down the scale, it
means towards the violet or the red end
respectively.</p>
<p>We may picture the spectrum as analogous
to the keyboard of a piano.</p>
<p>In the second part of this chapter, the
electron explains how it has enabled man
to discover that certain stars are approaching
the earth, while others are receding from it.</p>
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<p><span class="pagenum"><SPAN name="Page_159" id="Page_159"></SPAN></span>
We electrons had waited long ages for man
to acknowledge our services, but we did not
despise the acknowledgment which a few
men accorded us upon the basis of their
mathematical calculations. It was natural,
however, that we should want something
more definite than this.</p>
<p>You can imagine our joy when real experimental
proof of our existence was established.
Perhaps you think that we should
have been satisfied with this. But even this did
not bring acknowledgment from many outside
scientific circles, and not even from all
within those circles. As our services to man
are universal, we feel that all men should
become acquainted with our doings. Indeed
that was the chief argument used by my
fellow-electrons, who urged me to write this
<span class="pagenum"><SPAN name="Page_160" id="Page_160"></SPAN></span>
autobiography. The story of our actual discovery
by man is an interesting one.</p>
<p>It all came about in a very simple manner,
but in quite a different way from what most
electrons expected. Man reasoned within
himself that if we electrons really did revolve
around atoms and thus produce waves in the
æther, as had been suggested, he ought to
be able to affect our movements by disturbing
the æther in which we were revolving. Of
course man cannot disturb the æther directly;
he must employ some of us to do this for
him. He caused us to produce a very powerful
magnetic field, which, as you know, is a
disturbance of the æther. Man did not bother
thinking about <i>us</i> in this connection; he
simply sent an electric current around an
electro-magnet, but I have explained to you
the very active part we play in electric and
magnetic actions.</p>
<p>From my story in the preceding chapter,
you are aware that man had observed the
meaning of the bright lines in the spectrum
of any incandescent body. When he examined
the æther waves we send out from sodium
atoms, he found two very distinct lines in
the yellow. Because of the brightness of
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these lines, man selected a sodium flame to
experiment with in the present case.</p>
<p>You will picture a great host of my fellow-electrons
revolving around the atoms in a
sodium flame. The flame was placed between
the poles of a very powerful electro-magnet,
and a beam of æther waves (light) produced
by us was directed into the spectroscope.
The experimenter focussed all his attention
upon one of the bright yellow lines. He
noted very carefully the exact position in
which we placed it. He then produced the
magnetic field around the flame, in which
my fellow-electrons were revolving at a steady
pace, and, behold, the line which he was
watching split up into two lines, one taking
up a position a little higher up the spectrum
scale, and the other going a little lower down
towards the red end. What could this
mean?</p>
<p>Man had no difficulty in knowing the cause
of this alteration; indeed, it was exactly what
he had hoped would take place. Of the two
new lines, one represented waves a little
shorter, while the other line indicated waves
a little longer or farther apart, than the
original waves forming the single line. This
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could only come about by some of the electrons
having had their rate of revolution increased,
while that of others had been reduced. These
alterations were due to the æther disturbance
(the magnetic field). Those electrons whose
orbits happened to lie in one position had
their rate of revolution increased, while those
whose orbits lay in another position had their
speed reduced. Man was convinced at last
that we "particles" were real existing things.</p>
<p>Whenever man withdrew the æther disturbance,
the electrons fell back into their
natural rate of revolution, and the original
single line appeared in the spectrum.</p>
<p>I took no part in the original experiment
which gave absolute proof of our existence,
but since then I have been present in a
laboratory when the same experiment has
been repeated.</p>
<p>This is not the only case in which we
alter the positions of definite lines in the
spectrum. Indeed, we have given man some
interesting information about the motions of
distant stars—information which he could
not have obtained in any other way. We
have sent wireless messages from distant
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stars, indicating that they were approaching
the earth, while electrons aboard other stars
have signalled that they are receding from
the earth. All this may seem mysterious to
you, and yet our actions in the matter are
very simple. Indeed, we do nothing but what
I have told you of in the preceding chapters.
We send out definite wave-lengths in the
manner described already. But if we are
on board a star which is travelling towards
the earth, our waves will naturally follow
a little closer at each other's heels. On the
other hand, if the star is receding from the
earth, the waves must be a little farther
apart than they would be if the star were
at rest.</p>
<p>You will understand that the electrons are
revolving at the same speeds in both cases,
but the forward movement of the star crowds
the waves together, while a receding star
stretches them out a little farther apart.
The result at the receiving end is that the
crowded waves are just as though they had
come from electrons revolving at a greater
speed than is actually the case. Hence the
line appears farther along the spectrum, up
the scale of frequencies, than would have
<span class="pagenum"><SPAN name="Page_164" id="Page_164"></SPAN></span>
been the case had the star not been moving
forward in the line of sight. Thus if the
hydrogen lines, of which I have spoken elsewhere,
should appear higher up the spectrum
than usual, then man knows that the star
from which these waves are coming is approaching
the earth.</p>
<p>It will be evident that when known lines
in the spectrum are shifted down the scale
(towards the red end of the spectrum), then
the rate of the waves has been decreased,
and man knows that the star carrying these
stimulating electrons is receding from him.</p>
<p>You will observe that we electrons perform
no new duty in connection with this matter;
it is entirely the motion of the body carrying
us that alters the positions of the lines. But
I must hasten on to tell you of some personal
experiences.</p>
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