AT last the thing is finished, and the designs and models for the new illuminant are complete. In a little while the arrangements for patenting the invention all over the world will be made, and then I shall able to speak with more freedom as to the details of the thing. In the meantime, as will be readily understood, can do little more than indicate its general features. And now, since my time is a little less occupied than it has been of late, I am free to write down, as I have been often asked to do, the details of a curious experience which occurred to me while at work on the new light.

      There are people, I am told, who collect statistics of such things, compare and investigate them.

      Well, in that case, here are the trivial facts for what they are worth, and anybody can investigate them who pleases. Nobody must think that I am imaginative or superstitious, for indeed I'm not. The fact simply is that I have not been able discover the physical cause (for no doubt there must have been a physical cause) of a rather odd incident — an incident, however, that saved my life, odd as it was.

      You will have noticed that I speak not of "my" invention or "my" new illuminant, but of "the" invention, "the" new light. This is because the main merit — indeed, I may say the whole merit — of the discovery belongs not to me but to my father, who lost his life an accident in one of his experiments.

      My father was an engineer, retired. He had begun in the active branch, and for many years was chief engineer on one of the great steamship lines. It was then that he lost the forefinger of his right hand in snatching away an assistant whose coat had been caught between gear-wheels.

      But he was never idle. He had a small workshop built out at the back the house, consisting of two rooms and a lobby, and it was there that I, his only son, received my mechanical training.

      One or two small inventions issued from this little workshop, and the name of John Dixon appeared as many times on the official patents list; but his great project was the new light. I may go so far as to say that it was a combustible gas, produced in a very like manner to acetelyne gas. Acetelyne, you may know, is produced by the direct union of carbon and hydrogen at a high temperature. In an acetelyne gas lamp water is brought into contact with calcium carbide. The calcium decomposes the water and becomes lime, setting free the hydrogen from the water, which combines with the carbon.

      But in the lamp which my father resolved to make, and which I now have perfected, another metal than calcium was used, the name of which will be found duly set forth in the patent specification when it is published. It is obscure metal, as yet unused in the arts, but my father discovered that under particular treatment it would produce a peculiar unknown gas. This gas readily combined with carbon and gave out gas of a different nature, slowly combustible, with little heat, but most intense illuminating power. In every respect it was superior to all known illuminating agents, except that, as first prepared by my father, it was too expensive for general commercial purposes. It remained for him to invent some cheaper treatment of the metal which would show equally good results.

      But my father said, "Old Jack Dixon isn't to be frightened off a big thing like this, my boy — at any rate, not by a little pop or two." And he persevered, with stronger containers and cylinders.

      He was a big, loud-voiced man, and very enthusiastic. "Charley," he would say to me, "Charley, my boy, this is to be the biggest thing since the telephone. I'm pretty comfortably off now, but when this is done we'll be millionaires, and your children's children after you! Dixon's light will be burning when we're all dead and buried!"

      "But do take care, John," my mother would say. "I'm afraid of explosions."

      "That's all right," he would reply. "All the explosions are over now; and they only broke a window or so. In about a year's time I'll be buying you a diamond necklace of half-a-pound weight, my dear!"

      My mother shook her head and smiled. "I'd rather have my husband with all his arms and legs," she said.

      Well, at last, "the" explosion came. My father was in the further room of the workshop, working at his containers and receivers, and I was at the door of the outer lobby sharpening a chisel on the grindstone. There was a great thud, and I saw the glass fly out of the end windows. I rushed in, and there was my father in a heap, in the angle of the wall opposite his bench, bleeding and insensible, and the place a wreck.

      My mother was out, but servants were soon there to help, and very soon my father was on the dining-room sofa, with the doctor in attendance. He regained his senses for hour or so, but that was all. He died at two o'clock in the morning.

      While he was sensible he was, nevertheless, very weak. Still he recognised me with a wan smile, and said: "It was a hard whack that time, Charley!" And shortly afterward he whispered certain instructions, and bade me see about getting containers made of a pattern he had determined on early in the day.

      I went away as though to carry out his instructions, but, of course, I could do nothing, and as a matter of fact, the experiments were not renewed for four or five months after our terrible loss. Indeed, it was hard to get my mother to consent to renewing them at all. Her grief — and, indeed, my own — I say nothing about (since it has nothing to do with the circumstance I am to record), except to observe that it prevented my getting to work for some time.

      But I devised a means whereby I might remain in the next room during the time when any danger of an explosion existed, or, at any rate, during a good deal of the time. It was awkward and very inconvenient, but I had to do it for my mother's peace mind. I believe that even with these restrictions she only consented because she had a feeling that in perfecting the invention I should be carrying out the dearest wish of my dead father.

      Well, the experiments went on from the point where they were interrupted, and I had no more explosions. I could feel that I was groping my way nearer and nearer the solution of the difficulty, and I worked hard for months — in fact, to near the anniversary of my father's death, and still with no accident.

      One day I resolved to try the introduction into the receiver of a substance I had not yet experimented with. It was not indicated in any of my father's notes, and I was not fully acquainted with its properties in all circumstances. Still, I had my ideas of what its action would be, and in it went. The receiver for the resultant gas was set in order, and I retired into the other room of the workshop, in accordance with my promise to my mother, shutting the door behind me. This time I felt quite certain that there was no possibility of danger, but I had promised, and there was an end of it. I resolved to allow ten minutes by my watch for the trial to work, and turned to do something useful in the meantime.

      The room I was in contained two lathes, a small shaping-machine, and few other things of the sort, the laboratory work being carried out in the room I had just left. It was now dark, and the work-room was lighted by a small incandescent electric lamp at the opposite end to the door of the laboratory, over a lathe. I picked up the rough of a small brass screw-cap for a lamp, and turned it down a bit on the lathe under the light.

      I grew absorbed in the work, for it was necessary to make a very accurate turning of that cap, and took longer than I realised. When I looked at my watch I saw that it was full twelve minutes since I left the other room, so I turned at once and made for the door. It was an ordinary deal panelled door, painted white. As I was in the act of reaching toward the handle there fell across the door, straight before my eyes, the black shadow of hand and arm, with fingers extended as though to stop me.

      I started back — naturally, I think. The thought that flashed through my mind was that somebody had come quietly in at the other end of the room and had reached across before the light. I turned my head, but I was alone. Nothing hung before the light, but there was the shadow!

      Now I am in some way a man of science, and I know that a shadow is nothing but the cutting off by an opaque body of light, transmitted from its source in straight lines. There was but the one light in the room, and I knew that something, not necessarily a hand, was causing this odd shadow.

      The beams that spanned the roof were used as a convenient rest for pieces of scrap iron, rods, and so forth, and glancing up I saw that an oddly shaped piece of iron was hanging over a beam. I reached up and pushed it aside, but I instantly perceived that it was not the cause of the shadow, for it threw its own shadow high up on the wall. There was nothing, absolutely nothing, between the light and the door to cause any shadow whatever.

      I stood astonished and perplexed. I extended my own hand, to cast a shadow below the other. And it was only now, seeing the two shadows together, that I noticed that a finger was missing from the upper hand. And scarce had I perceived it when the shadow became violently agitated, moving rapidly up and down on the white panel of the door.

      I saw no more, for with that the door came at me, and with a splitting crash I found myself at the other end of the room, half under the lathe, deafened and half-stunned. People came and dragged me out of it, but it was not for some time that I realised that I was still alive and had all my limbs about me. Bruised and stiff I was, it was true; but beyond that I was unhurt, though the explosion was far more violent than the last had been. Had I been in the laboratory, standing, as I should have been in that case, over my apparatus, I must certainly have been killed on the spot.

      Well, I think that is all. I told nobody of that extraordinary shadow until a day or two back, when my work was complete, and then I told my mother. It affected her in a way that altogether amazed me. Because, I have said, as a man of science I know vary well that a shadow is nothing but interruption of light by an opaque body; and there must have been some simple natural cause for the one I saw, though I failed to discover it in the time available. Still, there is an odd coincidence, perhaps, in the missing finger. I think I have said somewhere above that my father lost a finger once at sea, between gear-wheels.

THE END.