Ferguson stepped forward briskly. "Mr. Kent, let me see if I can lift
you inside the casket; make yourself limp--that's it!" as Kent, entering
into the investigation heart and soul, relaxed his muscles and fell back
against the detective.

A moment later he was swung upward and pushed head-first inside the
casket and the door closed. The air, though close, was not unpleasant
and Kent, his eyes growing gradually accustomed to the dark interior,
tried to discover the trap door at the top of the box but without
success. Putting out his hands he felt along the top. The height of the
casket did not permit him to sit up, so he was obliged to slide his
body down toward his feet to feel along the sides of the casket. This
maneuver soon brought his knees in violent contact with the top, and at
the sound Ferguson opened the door and assisted him out.

"Had enough of it?" he asked, viewing Kent's reddened cheeks with faint
amusement. "I wonder if Grimes could breathe in there for any lengthy
period. If so, it would help establish the time which elapsed between
his being incarcerated and your finding him, Colonel."

"How so?" demanded McIntyre.

"Well, if he couldn't get air and you hadn't discovered him at once,
he'd have died," explained Ferguson. "If you did find him immediately
the person who knocked him down must have made a lightning escape."

"Air does get in the casket in some way," broke in Kent. "It wasn't so
bad inside. Colonel McIntyre," Kent stopped a moment to remove a piece
of red sealing wax clinging to the cuff of his suit. It had not been
there when he entered the casket. Kent dropped the wax in his vest
pocket as he again addressed his host. "Who first discovered Grimes in
the casket?"

"Mrs. Brewster."

"And what was Mrs. Brewster doing in the library at that hour?" glancing
keenly at McIntyre as he put the question.

"She could not sleep and came down for a book," explained the Colonel.

Ferguson, who had walked several times around the library, looking
behind first one and then the other of the seven doors, paused to ask:

"What attracted Mrs. Brewster's attention to the casket?"

"The blood stain on its side," McIntyre answered.

"What--that!" Ferguson eyed McIntyre incredulously. "Come, sir, do you
mean to tell me she noticed that little bit of a stain in a dark room?"

"She had an electric torch," shortly.

"But why should she turn the torch on this casket?" persisted the
detective. "She