was knitted in an anxious frown. His questions to
Guerchard showed a far less keen interest in the affair.

To him the lunch seemed very long and very tedious; but at last it came
to an end. M. Gournay-Martin seemed to have been much cheered by the
wine he had drunk. He was almost hopeful. M. Formery, who had not by
any means trifled with the champagne, was raised to the very height of
sanguine certainty. Their coffee and liqueurs were served in the
smoking-room. Guerchard lighted a cigar, refused a liqueur, drank his
coffee quickly, and slipped out of the room.

The Duke followed him, and in the hall said: "I will continue to watch
you unravel the threads of this mystery, if I may, M. Guerchard."

Good Republican as Guerchard was, he could not help feeling flattered
by the interest of a Duke; and the excellent lunch he had eaten
disposed him to feel the honour even more deeply.

"I shall be charmed," he said. "To tell the truth, I find the company
of your Grace really quite stimulating."

"It must be because I find it all so extremely interesting," said the
Duke.

They went up to the drawing-room and found the red-faced young
policeman seated on a chair by the door eating a lunch, which had been
sent up to him from the millionaire's kitchen, with a very hearty
appetite.

They went into the drawing-room. Guerchard shut the door and turned the
key: "Now," he said, "I think that M. Formery will give me half an hour
to myself. His cigar ought to last him at least half an hour. In that
time I shall know what the burglars really did with their plunder--at
least I shall know for certain how they got it out of the house."

"Please explain," said the Duke. "I thought we knew how they got it out
of the house." And he waved his hand towards the window.

"Oh, that!--that's childish," said Guerchard contemptuously. "Those are
traces for an examining magistrate. The ladder, the table on the
window-sill, they lead nowhere. The only people who came up that ladder
were the two men who brought it from the scaffolding. You can see their
footsteps. Nobody went down it at all. It was mere waste of time to
bother with those traces."

"But the footprint under the book?" said the Duke.

"Oh, that," said Guerchard. "One of the burglars sat on the couch
there, rubbed plaster on the sole of his boot, and set his foot down on
the carpet. Then he dusted the rest of the plaster off his boot and put
the book on the top of the footprint