Mary Roberts Rinehart

“ The slip had said "chimney." It was the only clue, and a house as large as Sunnyside was full of them. There was an open fireplace in my dressing-room, but none in the bedroom, and as I lay there, looking around, I thought of something that made me sit up suddenly. ”

“ With Halsey found and improving in health, and with at last something to work on, I began that day, Thursday, with fresh courage. As Mr. Jamieson had said, the lines were closing up. That I was to be caught and almost finished in the closing was happily unknown to us all.
It was late when I got up. I lay in my bed, looking around the four walls of the room, and trying to imagine behind what one of them a secret chamber might lie. Certainly, in daylight, Sunnyside deserved its name: never was a house more cheery and open, less sinister in general appearance. ”

“ The trunk-room, just over my head, had an open fireplace and a brick chimney, and yet, there was nothing of the kind in my room. I got out of bed and examined the opposite wall closely. There was apparently no flue, and I knew there was none in the hall just beneath. The house was heated by steam, as I have said before. In the living-room was a huge open fireplace, but it was on the other side.
Why did the trunk-room have both a radiator and an open fireplace? Architects were not usually erratic! ”