“I have been thinking this matter over carefully for some time,” began Hamerly, in his rather careful tones, once we were seated, “and if you do not object I should like to present my theories.” “Go right ahead,” said Tom. Hamerly went on somewhat thoughtfully. “I think you are wrong in saying we ought to follow the methods of Sherlock Holmes. We ought rather to follow Dupin, Poe’s detective, the man who preceded Sherlock Holmes. Try to reason out what the doctor would have on hand with regard to the power, and where he would have it. Try to analyze the action of his brain, rather than hunt for minute data. Let’s see what we know about Dr. Heidenmuller. He was a German of the most typical student type. That means he would never do anything without putting it down on paper. He had every desire to keep what he was doing from those around him. That is evident from the fact that Swenton never knew anything about the interior of this room. If the doctor made notes, as I believe he must have done, he would have wanted them within reach. So he must have had them in this room. He was a brilliant scientist, therefore he would not by preference have used any of the ordinary methods of concealment. His notes and apparatus were likely to take up a comparatively large amount of space, so that we are impelled to the definite conclusion that there is a concealed closet somewhere in that inner chamber. If we could take the time to remove the whole of the walls, and could get permission to do so, we could, I believe, find the hiding place, but that would involve time, expense, and running down the people who at present control the place and own the apparatus. I strongly question whether that would be worth while.” “No,” said Tom, “I don’t believe it would. If there were any chance of the man who has hired this place being the man we are after, I’d say go for him at any cost, but I don’t believe there’s one chance in a thousand that it is. He’s too sharp to stay around where Dr. Heidenmuller died under such peculiar circumstances.” “I agree to that,” said Hamerly. “And I, too,” I chimed in. Dorothy said nothing, but as I watched her, I saw the rose of her cheeks growing deeper, and that peculiar change in her eye that showed she had already leaped beyond the reasoning of the others and grasped the answer by intuition. “One question first,” she began, “Mr. Swenton, did the doctor leave the door to the spectroscope room open when he went into his private room?” “No,” answered Swenton slowly, “he would go into the spectroscope room, lock that door, and then you could hear the inner door open and shut. Sometimes he would not come out again, but I have often heard him come out into the anteroom about three or four minutes after he went in, stay there for a minute or two, then go in again and come out once more. After that he would be shut up there for hours together.”