all my faculties--had wrestled with a man invisible in the bright glare of an incandescent lamp? I said to myself: "It is necessary to assume that Navarro is a true medium, if only for the sake of argument. Well, in that case it is clear that Dr. Belleville and Sir Robert Ottley had found in the tomb of Ptahmes a papyrus containing a tremendous scientific secret. This secret is one which teaches its possessors how to control forces of Nature, in a manner which my imagination can only guess at, for the production of a physical result which I have actually experienced. They have learned how to override the laws of light. They have discovered a means of not only rendering opaque objects transparent, but positively invisible. And they are using their secret knowledge to further their nefarious designs. Sir Robert Ottley is using it to increase his fortune by spying out the financial secrets of his business rivals. Dr. Belleville is using it to accomplish the destruction of Captain Weldon, his rival in love. And, in all probability, they both intend it to remove me from their path because they fear that I suspect them." It must not be supposed that I adopted these conclusions with any sort of confidence. They entered my mind and remained there. But I received them churlishly and treated them as unwelcome guests. And the only reason that I did not expel them was because I could not discover, try as I would, any more substantial or sensible explanation of an event which they pretended to explain.