In the following short chapter the electron is made to sum up a few of the wonders which it has related, in order to focus our attention upon the grand place which the electrons occupy in the universe. CHAPTER XX CONCLUSION From what I have told you of myself and my fellow-electrons, it must be apparent that we are of tremendous importance to man. I have told you something of the part we played in building up this world--how we not only form the atoms of matter, but also hold these bricks of the universe together. I have given you a rough sketch of the composition of these bricks. You must have realised also that without us the whole universe would be in darkness. There would be no light, no heat, and consequently no life. Indeed, there could be no material existence without us. Where would man be if we failed to perform our mission? He could not exist if we even neglected a few of our duties. Not only do we form the atoms of which his body is composed, also holding these together, but we produce all those chemical changes within his body which are absolutely necessary to maintain life. His very thoughts are dependent upon our activities. I have told you how we send man's messages across the earth, and how we transmit power from place to place. Also how we have enabled man to gain knowledge of the distant stars, and to examine the bones of his living body. If man could cross-examine me or any of my fellows, I expect the first question would be--What are you electrons made of? But man must find this out for himself. The Creator has placed man in a world full of activity, and it is of intense interest to man to discover the meaning of all that lies around him. That is why I have been bound over by my fellows to tell you only so much of our history as man has discovered. But I am disclosing no secret when I admit that our very existence as electrons is dependent upon the æther. If I can find another scribe to write a revised biography for me a few hundred years hence, I shall have a much more interesting tale to tell, for many of our doings, of which man knows nothing at present, will be secrets no longer by that time. APPENDIX _THE SCRIBE'S NOTE ON APPENDIX_ As explained by the author in Chapter I., this appendix has been added for the sake of those readers who may wish further details than have been given in the electron's story. It is only necessary to give a brief notice of the more important particulars, as the author has written recently upon this subject in a popular form.[1] [Footnote 1: "Scientific Ideas of To-day." By Chas. R. Gibson, F.R.S.E. (London: Seeley & Co., Ltd. Five shillings net.)] APPENDIX It was known two thousand years ago that when a piece of amber was rubbed with a woollen cloth, the amber would attract light objects towards it. Amber was considered to be unique in this respect.