The girl was dismissed, with a warning not to talk of the affair.  And she was followed by the housekeeper, with no better result.

Thus all the domestics of the establishment were called and examined singly; but without success.

When the last servant was done with, and sent out of the room, the detective walked up to the duke.

“Well, Mr. Setter?” inquired the latter.

“Your grace, I have learned nothing from the servants but what you have already told me.”

“Do you still wish to search the premises?”

“If your grace pleases.  And I wish to begin with the apartments of the duchess.”

“Then follow me.  I myself will be your guide,” said the duke, leading the way from the library.

It would be useless to accompany the detective in this third search.  Let it be sufficient to say that this search was thorough, complete, exhaustive, and—­unsuccessful.

It was late in the day when it was finished, and the duke and the detective returned to the library.

“You now perceive Mr. Setter, that a day has been lost in these repeated searchings and questionings, and no new information, no sign of a clew to the fate of the duchess has been gained.  In an hour I must leave the house to catch the Great Northern Night Express.  I leave—­I am forced for the present, to leave the fate of my beloved wife in your hands.  In saying that, I say that I leave more than my own life in your keeping.  Use every means, employ every agency, spend money freely, the day you bring her safely to me, I will deposit ten thousand pounds in the Bank of England to your account.”

“Your grace is munificent.  If the duchess is on earth, I will find her;—­not for the reward only, though it is certainly a very great inducement to a poor man with a large family; but for the love and honor I bear your grace and the late Sir Lemuel Levison,” said the detective, earnestly, as he bowed and took leave.

The first dinner-bell rang.

The duke hastened to his own room, not to dress for dinner, but to prepare for his night journey to Scotland.

He ordered his valet to pack a valise with all that would be necessary for a few days’ absence, and then sent him to call a close cab.

By this time the second dinner-bell rang, and the duke went down, not to dine, but to take leave of Lady Belgrade.

He found her ladyship in the drawing-room.

“Give me your arm to dinner, if you please, Duke,” she said, rising.

“I hope you will excuse me; but I have only come to say good-by.  I have but time to catch the train.  Kerr has already put my luggage in the cab, which is waiting for me at the door.  Good-by, dear Lady Belgrade.  You will co-operate with Setter in all things necessary to a successful search, I know.  Setter has my orders to report to you—­”

“You take my breath away!” gasped the dowager.