She ceased, for just then they heard the floor creak under a step downstairs.  Rouletabille stopped Matrena short and drew his revolver.  He wished to creep down alone, but he had not time.  As the floor creaked a second time, Matrena’s anguished voice called down the staircase in Russian, “Who is there?” and immediately the calm voice of Natacha answered something in the same language.  Then Matrena, trembling more and more, and very much excited keeping steadily to the same place as though she had been nailed to the step of the stairway, said in French, “Yes, all is well; your father is resting.  Good-night, Natacha.”  They heard Natacha’s step cross the drawing-room and the sitting-room.  Then the door of her chamber closed.  Matrena and Rouletabille descended, holding their breath.  They reached the dining-room and Matrena played her dark-lantern on the sofa where the general always reclined.  The sofa was in its usual place on the carpet.  She pushed it back and raised the carpet, laying the floor bare.  Then she got onto her knees and examined the floor minutely.  She rose, wiping the perspiration from her brow, put the carpet hack in place, adjusted the sofa and dropped upon it with a great sigh.

“Well?” demanded Rouletabille.

“Nothing at all,” said she.

“Why did you call so openly?”

“Because there was no doubt that it could only be my step-daughter on the ground-floor at that hour.”

“And why this anxiety to examine the floor again?”

“I entreat you, my dear little child, do not see in my acts anything mysterious, anything hard to explain.  That anxiety you speak of never leaves me.  Whenever I have the chance I examine the flooring.”

“Madame,” demanded the young man, “what was your daughter doing in this room?”

“She came for a glass of mineral water; the bottle is still on the table.”

“Madame, it is necessary that you tell me precisely what Koupriane has only hinted to me, unless I am entirely mistaken.  The first time that you thought to examine the floor, was it after you heard a noise on the ground-floor such as has just happened?”

“Yes.  I will tell you all that is necessary.  It was the night after the attempt with the bouquet, my dear little monsieur, my dear little domovoi; it seemed to me I heard a noise on the ground-floor.  I hurried downstairs and saw nothing suspicious at first.  Everything was shut tight.  I opened the door of Natacha’s chamber softly.  I wished to ask her if she had heard anything.  But she was so fast asleep that I had not the heart to awaken her.  I opened the door of the veranda, and all the police — all, you understand — slept soundly.  I took another turn around the furniture, and, with my lantern in my hand, I was just going out of the dining-room when I noticed that the carpet on the floor was disarranged at one corner.  I got down and my hand struck a great fold of carpet