As I drove rapidly up to the house from Casanova Station in the hack, I saw the detective Burns loitering across the street from the Walker place. So Jamieson was putting the screws on—lightly now, but ready to give them a twist or two, I felt certain, very soon. The house was quiet. Two steps of the circular staircase had been pried off, without result, and beyond a second message from Gertrude, that Halsey insisted on coming home and they would arrive that night, there was nothing new. Mr. Jamieson, having failed to locate the secret room, had gone to the village. I learned afterwards that he called at Doctor Walker’s, under pretense of an attack of acute indigestion, and before he left, had inquired about the evening trains to the city. He said he had wasted a lot of time on the case, and a good bit of the mystery was in my imagination! The doctor was under the impression that the house was guarded day and night. Well, give a place a reputation like that, and you don’t need a guard at all,—thus Jamieson. And sure enough, late in the afternoon, the two private detectives, accompanied by Mr. Jamieson, walked down the main street of Casanova and took a city-bound train. That they got off at the next station and walked back again to Sunnyside at dusk, was not known at the time. Personally, I knew nothing of either move; I had other things to absorb me at that time. Liddy brought me some tea while I rested after my trip, and on the tray was a small book from the Casanova library. It was called _The Unseen World_ and had a cheerful cover on which a half-dozen sheeted figures linked hands around a headstone. At this point in my story, Halsey always says: “Trust a woman to add two and two together, and make six.” To which I retort that if two and two plus X make six, then to discover the unknown quantity is the simplest thing in the world. That a houseful of detectives missed it entirely was because they were busy trying to prove that two and two make four. The depression due to my visit to the hospital left me at the prospect of seeing Halsey again that night. It was about five o’clock when Liddy left me for a nap before dinner, having put me into a gray silk dressing-gown and a pair of slippers. I listened to her retreating footsteps, and as soon as she was safely below stairs, I went up to the trunk-room. The place had not been disturbed, and I proceeded at once to try to discover the entrance to the hidden room. The openings on either side, as I have said, showed nothing but perhaps three feet of brick wall. There was no sign of an entrance—no levers, no hinges, to give a hint. Either the mantel or the roof, I decided, and after a half-hour at the mantel, productive of absolutely no result, I decided to try the roof.