ollowed wonderingly. The houses in Brunswick Square are somewhat
irregular in point of architecture, and Nos. 218 and 219 were the only
matched pair thereabouts. Signs were not wanting, as Bell pointed out,
that at one time the houses had been occupied as one residence. The two
entrance-halls were back to back, so to speak, and what had obviously
been a doorway leading from one to the other had been plastered up within
comparatively recent memory.

The grim and dusty desolation of an empty house seemed to be supplemented
here by a deeper desolation. Not that there was any dust on the ground
floor, which seemed a singular thing seeing that elsewhere the boards
were powdered with it, and festoons of brown cobwebs hung everywhere.
Bell smiled approvingly as David Steel pointed the fact out to him.

"Do you note another singular point?" the former asked.

"No," David said, thoughtfully; "I--stop! The two side-shutters in the
bay-windows are closed, and there is the same vivid crimson blind in the
centre window. And the self colour of the walls is exactly the same. The
faint discoloration by the fireplace is a perfect facsimile."

"In fact, _this_ is the room you were in the other night," Bell
said, quietly.

"Impossible!" Steel cried. "The blind may be an accident, so might the
fading of the distemper. But the furniture, the engravings, the fittings
generally--"

"Are all capable of an explanation, which we shall arrive at with
patience."

"Can we arrive at the number over the door with patience?"

"Exactly what I was coming to. I noticed an old pair of steps in the back
sitting-room. Would you mind placing them against the fanlight for me?"

David complied readily enough. He was growing credulous and interested in
spite of himself. At Bell's instigation he placed the steps before the
fanlight and mounted them. Over his head were the figures 218 in
elongated shape and formed in white porcelain.

"Now then," Bell said, slowly. "Take this pocket-knife, apply the blade
to the _right-hand_ lower half of the bottom of the 8--to half the small
O, in fact--and I shall be extremely surprised if the quarter section
doesn't come away from the glass of the fanlight, leaving the rest of the
figure intact. Very gently, please. I want you to convince yourself that
the piece comes away because it is broken, and not because the pressure
has cracked it. Now then."

The point of the knife was hardly under the edge of the porcelai