Chapter XVI: How Man Proved Our Existence

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.

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 autobiography. The story of our actual discovery by man is an interesting one.

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 aether, as had been suggested, he ought to be able to affect our movements by disturbing the aether in which we were revolving. Of course man cannot disturb the aether 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 aether. Man did not bother thinking about _us_ 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.

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 aether waves we send out from sodium atoms, he found two very distinct lines in the yellow. Because of the brightness of these lines, man selected a sodium flame to experiment with in the present case.

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 aether 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?

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 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 aether 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.

Whenever man withdrew the aether disturbance, the electrons fell back into their natural rate of revolution, and the original single line appeared in the spectrum.

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.

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 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.

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 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.

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.

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.

CHAPTER XVII

MY X-RAY EXPERIENCES

_THE SCRIBE'S NOTE ON CHAPTER SEVENTEEN_

The present generation were all very much interested in the
discovery of X-rays.

With the aid of a battery and an induction coil, man causes an
energetic electrical discharge to pass through a vacuum tube.

When the flying electrons strike upon a little metal target
placed in their path, they produce the well-known Roentgen rays.

We have all become familiar with the great penetrating powers of
these rays.

The electron may be left to tell its own story.