The author has given some particulars about the æther in the first chapter (_What the Story is about_). In conjunction with that, the electron may be left to tell its own story. CHAPTER X HOW WE COMMUNICATE WITH DISTANT SHIPS Our duties in this case are totally different from those of which I have been telling you. While we electrons can do many wonderful things, we cannot march through space. We may be fired off like bullets from the sun to the earth, but that is quite another matter. I shall have something to say about that fact later on. You have seen already that man can make us jump only a very short distance, even when he has cleared our path of the obstructing air, as he does in a vacuum tube. If men were to provide us with a complete path of metal atoms from the shore to the ship, we could set to work upon the simple plan which I have described in the preceding chapter. But, needless to say, man has more sense than to attempt to keep up metallic connection with a ship going away out to sea. Even the wisest men were surprised when they heard that we electrons could signal through space to great distances without any connecting wires. We ourselves were not surprised. Had we not been doing this very thing from the foundation of the world? Our fellow-electrons in the sun have never ceased to communicate with those of us upon the earth. Of course I am referring at present to those æther waves which man calls _heat_ and _light_. But the waves which we make to carry man's messages through space are of the very same nature, the only difference being that they are much longer, or, in other words, much farther apart. They do not follow each other so closely, and they do not affect the eye or the sense of touch. However, these long waves are able to bestir some of us electrons who are situated at a great distance from the sending electrons. Our method of producing such waves in the æther is by surging to and fro from atom to atom in an upright wire. When we make a rapid to-and-fro motion we send out great waves in the æther. The original plan adopted by man was to make us jump across a spark-gap, but in this case also it was our rapid oscillation to and fro that produced the waves. If we wish the waves to carry to a great distance, we must club together in considerable force to supply the necessary energy. The energy which we can get from a battery and induction coil is not sufficient for any very long distances. In such cases we require the aid of a _dynamo_, a machine about which I shall have some experience to relate in another chapter.