been shattered by the
"bang or bump" which Flora Miles had described. _One of the big glass
jewels had been missing, leaving an unsightly hole._

No wonder there had been a "bang or bump" hard enough to dent the frame
of the window! For if his hunch was correct, the gun, wedged into the
big bowl, with the silencer slightly protruding from the jewel-hole, had
"kicked," just as it had kicked an hour before, when it had dislodged
itself from the hole in the hot-air register and clattered down the big
pipe to the heat reservoir of the furnace.

That the big lamp, when he, following Strawn, had first examined the
scene of Nita's murder, had not stood in front of the window frame, did
not dampen Dundee's excitement in the least. After Karen Marshall's
scream that room had been filled with excited people, who had rushed
about, looking out of the window for the murderer and doing all the
other things which terror-stricken people do in such a crisis. No, the
murderer--or murderess--had found no difficulty in shifting the big lamp
one foot nearer the chaise longue, to the place it had always occupied
before.

But--_how_ had the gun been fired from the lamp? Electrically? Another
picture flashed into Dundee's mind. He saw himself stooping, on Monday
afternoon, to see if the plug of the lamp's cord had been pulled from
the socket, saw it again as it was then--nearly out, so that no current
could pass from the baseboard outlet under the bookcase into the bronze
lamp. How far from the truth his conclusion that Monday had been!

But what was the _real_ truth?

Suddenly Dundee flung back the moss-green Wilton rug which almost
entirely covered the bedroom floor and revealed the bell which Dexter
Sprague had rigged up so that Nita might summon Lydia from her basement
room, in case of dire need--a precaution with which the murderer was
probably familiar, since Lois Dunlap might innocently have spread the
news of its existence.

There was a half-inch hole in the hardwood floor, and out of it issued a
length of green electric cord, connected with two small, flat metal
plates, one upon the other, so that when stepped upon a bell would ring
in Lydia's basement room.

But there was something odd about the wire. Although it was obviously
new, a section of it near the two metal plates was wrapped with black
adhesive tape. Another memory knocked for attention upon Dundee's mind.
_The long cord of the bronze lamp had been mended with exac