“A ghost?” interestedly.

“Yes.  My daughter,” said the admiral tolerantly, “believes that she hears strange noises at night, tapping, and such like.”

“Oh!” politely.  Breitmann broke his bread idly.  It was too bad.  She had not produced upon him the impression that she was the sort of woman whose imagination embraced the belief in spirits.  “Where does this ghost do its tapping?”

“In the big chimney in the library,” she answered.

No one observed Breitmann’s hand as it slid from the bread, some of which was scattered upon the floor.  The scars, betraying emotion such as no mental effort could control, deepened, which is to say that the skin above and below them had paled.

“Might it not be some trial visit of your patron saint, Santa Claus?” he inquired, his voice well under control.

“Really, it is no jest,” she affirmed.  “For several nights I have heard the noise distinctly; a muffled tapping inside the chimney.”

“Suppose we inspect it after luncheon?” suggested Fitzgerald.

“It has been done,” said the admiral.  Outwardly he was still skeptical, but a doubt was forming in his mind.

“It will do no harm to try it again,” said Breitmann.

If Fitzgerald noted the subdued excitement in the man’s voice, he charged it to the moment.

“Take my word for it,” avowed the admiral, “you will find nothing.  Bring the coffee into the library,” he added to the butler.

The logs were taken out of the fireplace, and as soon as the smoke cleared the young men gave the inside of the chimney a thorough going over.  They could see the blue sky away up above.  The opening was large, but far too small for any human being to enter down it.  The mortar between the bricks seemed for the most part undisturbed.  Breitmann made the first discovery of any importance.  Just above his height, standing in the chimney itself, he saw a single brick projecting beyond its mates.  He reached up, and shook it.  It was loose.  He wrenched it out, and came back into the light.

“See!  Nothing less than a chisel could have cut the mortar that way.  Miss Killigrew is right.”  He went back, and with the aid of the tongs poked into the cavity.  The wall of bricks was four deep, yet the tongs went through.  This business had been done from the other side.

“Well!” exclaimed the admiral, for once at loss for a proper phrase.

“You see, father?  I was right.  Now, what can it mean?  Who is digging out the bricks, and for what purpose?  And how, with the alarms all over the house, to account for the footprints in the flour?”

“It is quite likely that something is hidden in the chimney, and some one knows that it is worth hunting for.  This chimney is the original, I should judge.”  Fitzgerald addressed this observation to the admiral.

“Never been touched during my time or my father’s.  But we can soon find out.  I’ll have a man up here.  If there is anything in the chimney that ought not to be there, he’ll dig it out, and save our midnight visitor any further trouble.”