However, the electrons may claim to produce colour in the same sense as we savages produce pain in fellow-men by firing rifle-bullets at them. The electron explains how some objects appear white, while others are red, and so forth. It explains also how electrons produce artificial light. The electron twits man upon his ridiculously wasteful processes of obtaining artificial light. CHAPTER XIV HOW WE PRODUCE COLOUR In the preceding chapter I have been telling you how we electrons produce waves in the æther ocean. I pointed out that if we make the waves follow each other at too slow or too fast a rate they fail to affect man's eyes. It may seem strange to you that only a very small range of our æther waves should affect man's visionary apparatus. Of course this limitation lies beyond our province; we can produce endless variety of æther waves--it is man's organs which fail to appreciate the bulk of these. However, there is plenty of variety in the sensations which we can produce in man. If we make the waves follow each other at a certain speed, man says he has the sensation of _red_. If we move faster, he speaks of _orange-colour_, and as we increase our speed he names his further sensations as _yellow_, _green_, _blue_, and _violet_. Then if we combine all these waves--that is, if we produce them all at one time--he says he has the sensation of _white_. If we produce none of these waves, he calls the result _black_. While we electrons are very versatile, our actions are dependent in a great measure upon circumstances. For instance, if an electron is acting as a satellite to one particular kind of atom, its rate of revolution around that atom may be very different from that of an electron similarly attached to another kind of atom. We electrons are all identical, but the speed of revolution is determined by the kind of atom. The reason is very simple; electrons revolve around some atoms at a much greater distance than they would around other atoms. Those making only the smaller orbits not only get around their atoms in less time, but they are also travelling at a greater pace. It is this fact which enables the electrons to produce the various wave-lengths which stimulate the different colour sensations in the brain of man. I think you will have no difficulty in seeing how it is that we come to produce such a variety of wave-lengths--in other words, how we are able to make the waves follow each other more or less rapidly. You will understand that we do not produce colours; we merely make various waves in the æther, and these waves excite the colour sensations in man. I mention this simple fact, because I hear many people speaking of our æther waves as "coloured rays," which, of course, is quite a ridiculous description.