facts he had discovered.

He had stood there plunged in reflection for perhaps ten minutes,
when there came a sound of voices and footsteps on the stairs. He
awoke from his absorption, seemed to prick his ears, then slipped a
leg over the window-ledge, and disappeared from sight down the
ladder.

The door opened, and in came M. Formery, the Duke, and the
inspector. M. Formery looked round the room with eyes which seemed
to expect to meet a familiar sight, then walked to the other
drawing-room and looked round that. He turned to the policeman, who
had stepped inside the drawing-room, and said sharply, "M. Guerchard
is not here."

"I left him here," said the policeman. "He must have disappeared.
He's a wonder."

"Of course," said M. Formery. "He has gone down the ladder to
examine that house they're building. He's just following in our
tracks and doing all over again the work we've already done. He
might have saved himself the trouble. We could have told him all he
wants to know. But there! He very likely would not be satisfied till
he had seen everything for himself."

"He may see something which we have missed," said the Duke.

M. Formery frowned, and said sharply "That's hardly likely. I don't
think that your Grace realizes to what a perfection constant
practice brings one's power of observation. The inspector and I will