“How is it, then, that the woman who came into the room about nine left no traces with her muddy boots?”

“I am glad you raised the point. It occurred to me at the time. The charwomen are in the habit of taking off their boots at the commissionnaire’s office, and putting on list slippers.”

“That is very clear. There were no marks, then, though the night was a wet one? The chain of events is certainly one of extraordinary interest. What did you do next?

“We examined the room also. There is no possibility of a secret door, and the windows are quite thirty feet from the ground. Both of them were fastened on the inside. The carpet prevents any possibility of a trapdoor, and the ceiling is of the ordinary whitewashed kind. I will pledge my life that whoever stole my papers could only have come through the door.”

“How about the fireplace?”