At last the day arrived when my device was ready for the test. I had worked all the afternoon giving the finishing touches and it had grown dusk without my realizing it. But everything was now ready, and moving the switch, I turned the current of electricity through the composition. Just as I was about to begin my test, I noticed what appeared to be a faint shadow of a man move across the surface of the film. My first thought was that someone had entered the room without my knowledge, and his figure had been reflected on the surface of the film, which was highly glazed, but a glance around the room assured me that this explanation was untenable. Moreover, I found, upon further investigation, that the film was lying in such a position that it would be impossible to reflect any person in the room. I then examined the skylight, only to find that, owing to the sharp inclination of the roof, it would be an utter impossibility for anyone to reach it from the outside without the aid of a ladder. I investigated this source further, thinking to find the reflection on the film to be from some street in the city below, but on account of the extent of the roof, no street was visible from the skylight. Completely baffled, I descended into the room again and turned on the current. Immediately the shadow appeared on the film, and this time, in consequence of the room now being quite dark, I noticed that it was surrounded by a phosphorus-colored glow. The figure was certainly that of a man, although very faint, and it became evident to me, after watching it for a while, that he was trying to signal with his arms. I now noticed that, in addition to the peculiar light on the film, the entire surface seemed to vibrate with frequent, but scarcely audible, humming sounds. Upon turning off the current all disappeared, only to reappear when I switched it on again. It was evident then that the phenomenon was caused only when the instrument was charged with electricity, and consequently was no ordinary reflection, as I had at first supposed. Everything pointed to its being the manifestation of some outside agency; possibly electrical waves which my apparatus received and in a measure responded to, coming through the open skylight from--where? The question reiterated itself in my mind, as I stood gazing perplexedly at the phenomenon. I might have been satisfied with the supposition that, unknowingly, I had made an instrument which was capable of receiving wireless waves from another instrument of similar tone in or near Paris, if I had had only the humming sounds to contend with, but the shadow impelled me to look for the reason further than this. I glanced upward, eagerly seeking some explanation. One star was visible through the open skylight--Mars. Clear and bright it shone in the inky blackness framed by the window.