At The Foot of the Stairs

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.

I am not fond of a height. The few occasions on which I have climbed a
step-ladder have always left me dizzy and weak in the knees. The top
of the Washington monument is as impossible to me as the elevation of
the presidential chair. And yet--I climbed out on to the Sunnyside
roof without a second's hesitation. Like a dog on a scent, like my
bearskin progenitor, with his spear and his wild boar, to me now there
was the lust of the chase, the frenzy of pursuit, the dust of battle.
I got quite a little of the latter on me as I climbed from the
unfinished ball-room out through a window to the roof of the east wing
of the building, which was only two stories in height.