one of the burglars. And look here; here's a footprint under it—a footprint on the carpet," said the Duke.
M. Formery and the inspector came quickly to the spot. There, where the book had fallen, plainly imprinted on the carpet, was a white footprint. M. Formery and the inspector stared at it.
"It looks like plaster. How did plaster get here?" said M. Formery, frowning at it.
"Well, suppose the robbers came from the garden," said the Duke.
"Of course they came from the garden, your Grace. Where else should they come from?" said M. Formery, with a touch of impatience in his tone.
"Well, at the end of the garden they're building a house," said the Duke.
"Of course, of course," said M. Formery, taking him up quickly. "The burglars came here with their boots covered with plaster. They've swept away all the other marks of their feet from the carpet; but whoever did the sweeping was too slack to lift up that book and sweep under it. This footprint, however, is not of great importance, though it is corroborative of all the other evidence we have that they came and went by the garden. There's the ladder, and that table half out of the window. Still, this footprint may turn out useful, after all. You had better take the measurements of it, inspector. Here's a foot-rule for you. I make a point of carrying this foot- rule about with me, your Grace. You would be surprised to learn how often it has come in useful."
He took a little ivory foot-rule from his waist-coat pocket, and gave it to the inspector, who fell on his knees and measured the footprint with the greatest care.
"I must take a careful look at that house they're building. I shall find a good many traces there, to a dead certainty," said M. Formery.
The inspector entered the measurements of the footprint in his note- book. There came the sound of a knocking at the front door.
"I shall find footprints of exactly the same dimensions as this one at the foot of some heap of plaster beside that house," said M. Former; with an air of profound conviction, pointing through the window to the house building beyond the garden.
A policeman opened the door of the drawing-room and saluted.
"If you please, sir, the servants have arrived from Charmerace," he said.
"Let them wait in the kitchen and the servants' offices," said M. Formery. He stood silent, buried in profound meditation, for a couple of minutes. Then he turned to the Duke and said, "What was that you said about a theft of motor-cars at Charmerace?"
"When he received the letter from Arsene Lupin, M. Gournay-Martin decided to start for Paris at once," said the Duke. "But when we sent for the cars we found that they had just been stolen. M. Gournay-Martin's chauffeur and another servant were in the garage gagged and bound. Only an old car, a hundred horse-power Mercrac, was left. I drove it to Paris, leaving M. Gournay-Martin and his family to come on by train."
"Very important—very important indeed," said M. Formery. He thought for a moment, and then added. "Were the motor-cars the only things stolen? Were there no other thefts?"
"Well, as a matter of fact, there was another theft, or rather an attempt at theft," said the Duke with some hesitation. "The rogues who stole the motor-cars presented themselves at the chateau under the name of Charolais—a father and three sons—on the pretext of buying the hundred-horse-power Mercrac. M. Gournay-Martin had advertised it for sale in the Rennes Advertiser. They were waiting in the big hall of the chateau, which the family uses as the chief living-room, for the return of M. Gournay-Martin. He came; and as they left the hall one of them attempted to steal a pendant set with pearls which I had given to Mademoiselle Gournay-Martin half an hour before. I caught him in the act and saved the pendant."
"Good! good! Wait—we have one of the gang—wait till I question him," said M. Formery, rubbing his hands; and his eyes sparkled with joy.
"Well, no; I'm afraid we haven't," said the Duke in an apologetic tone,
"What! We haven't? Has he escaped from the police? Oh, those country police!" cried M. Formery.
"No; I didn't charge him with the theft," said the Duke.
"You didn't charge him with the theft?" cried M. Formery, astounded.
"No; he was very young and he begged so hard. I had the pendant. I let him go," said the Duke.
"Oh, your Grace, your Grace! Your duty to society!" cried M. Formery.
"Yes, it does seem to have been rather weak," said the Duke; "but there you are. It's no good crying over spilt milk."
M. Formery folded his arms and walked, frowning, backwards and forwards across the room.
He stopped, raised his hand with a gesture commanding attention, and said, "I have no hesitation in saying that there is a connection—an intimate connection—between the thefts at Charmerace and this burglary!"
The Duke and the inspector gazed at him with respectful eyes—at least, the eyes of the inspector were respectful; the Duke's eyes twinkled.
"I am gathering up the threads," said M. Formery. "Inspector, bring up the concierge and his wife. I will question them on the scene of the crime. Their dossier should be here. If it is, bring it up with them; if not, no matter; bring them up without it."
The inspector left the drawing-room. M. Formery plunged at once into frowning meditation.
"I find all this extremely interesting," said the Duke.
"Charmed! Charmed!" said M. Formery, waving his hand with an absent- minded air.
The inspector entered the drawing-room followed by the concierge and his wife. He handed a paper to M. Formery. The concierge, a bearded man of about sixty, and his wife, a somewhat bearded woman of about fifty-five, stared at M. Formery with fascinated, terrified eyes. He sat down in a chair, crossed his legs, read the paper through, and then scrutinized them keenly.
"Well, have you recovered from your adventure?" he said.
"Oh, yes, sir," said the concierge. "They hustled us a bit, but they did not really hurt us."
"Nothing to speak of, that is," said his wife. "But all the same, it's a disgraceful thing that an honest woman can't sleep in peace in her bed of a night without being disturbed by rascals like that. And if the police did their duty things like this wouldn't happen. And I don't care who hears me say it."
"You say that you were taken by surprise in your sleep?" said M. Formery. "You say you saw nothing, and heard nothing?"
"There was no time to see anything or hear anything. They trussed us up like greased lightning," said the concierge.
"But the gag was the worst," said the wife. "To lie there and not be able to tell the rascals what I thought about them!"
"Didn't you hear the noise of footsteps in the garden?" said M. Formery.
"One can't hear anything that happens in the garden from our bedroom," said the concierge.
"Even the night when Mlle. Germaine's great Dane barked from twelve o'clock till seven in the morning, all the household was kept awake except us; but bless you, sir, we slept like tops," said his wife proudly.
"If
