"I obtained from Carnes a history of your case, and when I found that your attacks grew violent with the full moon and subsided with the new moon, I was sure that I was on the right track, although I had at that time no way of knowing whether it was from natural or artificial causes that the effect was being produced. I interviewed Admiral Clay and found that you were suffering from a form of dermititis resembling sunburn, and that convinced me that an attack was being made on your sanity, for an excess of ultra-violet light will always tend to produce sunburn. I inquired about the windows of your solarium, for ultra-violet light will not pass through a lead glass. When the Admiral told me that the glass had been replaced with fused quartz, which is quite permeable to ultra-violet and that the change had been almost coincident with the start of your malady, I asked him to get you out of the solarium and let me examine it. "By means of certain fluorescent substances which I used, I found that your pillow was being bathed in a flood of ultra-violet light, and the fluoro-spectroscope soon told me that lunium emanations were present in large quantities. These rays were not coming to you directly from their source, but one of the windows of the State, War and Navy Building was being used as a reflector. I located the approximate source of the ray by means of an improvised apparatus, and we surrounded the place. Stokowsky was killed while attempting to escape. I guess that is about all there is to it." "Thank you, Doctor," said the President. "I would be interested in a description of the apparatus which he used to produce this effect." * * * * * "The apparatus was quite simple, Sir. It was merely a large collector of moonlight, which was thrown after collection onto a lunium plate. The resultant emanations were turned into a parallel beam by a parabolic reflector and focused, through a rock crystal lens with an extremely long focal length, onto your pillow." "Then Stokowsky had isolated Von Beyer's new element?" asked the President.