er was easy enough. It falls
apart into the figures three, five, seven, and nine; it was also
the simplest train of reasoning to apply these figures to the column
of dots. Only, I hadn't the remotest idea what the dots themselves
represented. Nor did it occur to me that the tortuous turnings of
any of the passageways of Hynds House might follow the pattern of
the Greek key, until The Author called your attention to the design
over the outside windows. Clever man, The Author!

"I lost the paper in the attic the night you heard me stumble on the
stairs. Fortunately, The Author put it in his coat in the closet and
locked the door on the outside. You can enter any room in the Hynds
House through those closet-walls, Sophy. They're paneled, remember.
I hated to have to go through The Author's pockets like a burglar,
but I had to have the key."

He handed me the flash-light.

"Now for the column of dots, each of which represents a brick," he
said, and began to count, from the first dark brick immediately
under the center of the triangle. At the third brick he paused; I
could see his fingers moving around the white line that, apparently,
held it in place. And that third brick, which looked so solidly
placed, turned as upon a pivot and swung out sideways. Still
counting from top to bottom, he paused at the fifth, the seventh,
and the ninth, and they, too, behaved in the same manner. As the
ninth one turned, that which had seemed a section of solid wall rose
soundlessly from the floor and left in its place an opening, a door,
as it were, some six feet high and about eighteen inches wide.

"It is not brick at all, but painted wood. A really wonderful bit of
work," explained Mr. Jelnik.

I could only stare, owlishly.

"You are wondering where we are?" He answered the unspoken question:
"Above the library, between the outside wall and the chimney-stacks.
You'd have to tear the house down to find it, without the Key." As
he spoke, he was lighting two of the candles Achmet had provided us
with, and although his hand was quite steady, he had become
frightfully pale. I, too, felt myself growing paler, felt again the
cold grue, as if the wind of death had stirred my hair.

"Reach into my breast pocket and you'll find a small vial. Put a
drop of the contents on your handkerchief and hold it against your
mouth for a moment," said Mr. Jelnik, with a sharp glance at me.

I obeyed mechanically. The scent had an indescribably tinglin