with a magnifying glass. There are no fragments of plaster on it. We dismiss the footprint. It is a mere blind, and a very fair blind too—for an examining magistrate."
"I understand," said the Duke.
"That narrows the problem, the quite simple problem, how was the furniture taken out of the room. It did not go through that window down the ladder. Again, it was not taken down the stairs, and out of the front door, or the back. If it had been, the concierge and his wife would have heard the noise. Besides that, it would have been carried down into a main street, in which there are people at all hours. Somebody would have been sure to tell a policeman that this house was being emptied. Moreover, the police were continually patrolling the main streets, and, quickly as a man like Lupin would do the job, he could not do it so quickly that a policeman would not have seen it. No; the furniture was not taken down the stairs or out of the front door. That narrows the problem still more. In fact, there is only one mode of egress left."
"The chimney!" cried the Duke.
"You've hit it," said Guerchard, with a husky laugh. "By that well- known logical process, the process of elimination, we've excluded all methods of egress except the chimney."
He paused, frowning, in some perplexity; and then he said uneasily: "What I don't like about it is that Victoire was set in the fireplace. I asked myself at once what was she doing there. It was unnecessary that she should be drugged and set in the fireplace— quite unnecessary."
"It might have been to put off an examining magistrate," said the Duke. "Having found Victoire in the fireplace, M. Formery did not look for anything else."
"Yes, it might have been that," said Guerchard slowly. "On the other hand, she might have been put there to make sure that I did not miss the road the burglars took. That's the worst of having to do with Lupin. He knows me to the bottom of my mind. He has something up his sleeve—some surprise for me. Even now, I'm nowhere near the bottom of the mystery. But come along, we'll take the road the burglars took. The inspector has put my lantern ready for me."
As he spoke he went to the fireplace, picked up a lantern which had been set on the top of the iron fire-basket, and lighted it. The Duke stepped into the great fireplace beside him. It was four feet deep, and between eight and nine feet broad. Guerchard threw the light from the lantern on to the back wall of it. Six feet from the floor the soot from the fire stopped abruptly, and there was a dappled patch of bricks, half of them clean and red, half of them blackened by soot, five feet broad, and four feet high.
"The opening is higher up than I thought," said Guerchard. "I must get a pair of steps."
He went to the door of the drawing-room and bade the young policeman fetch him a pair of steps. They were brought quickly. He took them from the policeman, shut the door, and locked it again. He set the steps in the fireplace and mounted them.
"Be careful," he said to the Duke, who had followed him into the fireplace, and stood at the foot of the steps. "Some of these bricks may drop inside, and they'll sting you up if they fall on your toes."
The Duke stepped back out of reach of any bricks that might fall.
Guerchard set his left hand against the wall of the chimney-piece between him and the drawing-room, and pressed hard with his right against the top of the dappled patch of bricks. At the first push, half a dozen of them fell with a hang on to the floor of the next house. The light came flooding in through the hole, and shone on Guerchard's face and its smile of satisfaction. Quickly he pushed row after row of bricks into the next house until he had cleared an opening four feet square.
"Come along," he said to the Duke, and disappeared feet foremost through the opening.
The Duke mounted the steps, and found himself looking into a large empty room of the exact size and shape of the drawing-room of M. Gournay-Martin, save that it had an ordinary modern fireplace instead of one of the antique pattern of that in which he stood. Its chimney-piece was a few inches below the opening. He stepped out on to the chimney-piece and dropped lightly to the floor.
"Well," he said, looking back at the opening through which he had come. "That's an ingenious dodge."
"Oh, it's common enough," said Guerchard. "Robberies at the big jewellers' are sometimes Worked by these means. But what is uncommon about it, and what at first sight put me off the track, is that these burglars had the cheek to Pierce the wall with an opening large enough to enable them to remove the furniture of a house."
"It's true," said the Duke. "The opening's as large as a good-sized window. Those burglars seem capable of everything—even of a first- class piece of mason's work."
"Oh, this has all been prepared a long while ago. But now I'm really on their track. And after all, I haven't really lost any time. Dieusy wasted no time in making inquiries in Sureau Street; he's been working all this side of the house."
Guerchard drew up the blinds, opened the shutters, and let the daylight flood the dim room. He came back to the fireplace and looked down at the heap of bricks, frowning:
"I made a mistake there," he said. "I ought to have taken those bricks down carefully, one by one."
Quickly he took brick after brick from the pile, and began to range them neatly against the wall on the left. The Duke watched him for two or three minutes, then began to help him. It did not take them long, and under one of the last few bricks Guerchard found a fragment of a gilded picture-frame.
"Here's where they ought to have done their sweeping," he said, holding it up to the Duke.
"I tell you what," said the Duke, "I shouldn't wonder if we found the furniture in this house still."
"Oh, no, no!" said Guerchard. "I tell you that Lupin would allow for myself or Ganimard being put in charge of the case; and he would know that we should find the opening in the chimney. The furniture was taken straight out into the side-street on to which this house opens." He led the way out of the room on to the landing and went down the dark staircase into the hall. He opened the shutters of the hall windows, and let in the light. Then he examined the hall. The dust lay thick on the tiled floor. Down the middle of it was a lane formed by many feet. The footprints were faint, but still plain in the layer of dust. Guerchard came back to the stairs and began to examine them. Half-way up the flight he stooped, and picked up a little spray of flowers: "Fresh!" he said. "These have not been long plucked."
"Salvias," said the Duke.
"Salvias they are," said Guerchard. "Pink salvias; and there is only one gardener in France who has ever succeeded in getting this shade- -M. Gournay-Martin's gardener at Charmerace. I'm a gardener myself."
"Well, then, last night's burglars came from Charmerace. They must have," said the Duke.
"It looks like it," said Guerchard.
"The Charolais," said the Duke.
"It looks like it," said Guerchard.
"It must be," said the Duke. "This IS interesting—if only we could get an absolute proof."
"We shall get one presently," said Guerchard confidently.
"It is interesting," said the Duke in a tone of lively enthusiasm. "These clues—these tracks which cross one another—each fact by degrees falling into its proper place—extraordinarily interesting." He paused and took out his cigarette-case: "Will you have a cigarette?" he said.
"Are
