F——­, coming back, had not observed the movement of the chair.  He employed himself now in stilling the dog.  I continued to gaze on the chair, and fancied I saw on it a pale blue misty outline of a human figure, but an outline so indistinct that I could only distrust my own vision.  The dog now was quiet.

“Put back that chair opposite me,” said I to F——­; “put it back to the wall.”

F——­ obeyed.  “Was that you, sir?” said he, turning abruptly.

“I!—­what?”

“Why, something struck me.  I felt it sharply on the shoulder—­just here.”

“No,” said I.  “But we have jugglers present, and though we may not discover their tricks, we shall catch them before they frighten us.”

We did not stay long in the drawing-rooms—­in fact, they felt so damp and so chilly that I was glad to get to the fire upstairs.  We locked the doors of the drawing-rooms—­a precaution which, I should observe, we had taken with all the rooms we had searched below.  The bedroom my servant had selected for me was the best on the floor—­a large one, with two windows fronting the street.  The four-posted bed, which took up no inconsiderable space, was opposite to the fire, which burnt clear and bright; a door in the wall to the left, between the bed and the window, communicated with the room which my servant appropriated to himself.  This last was a small room with a sofa-bed, and had no communication with the landing-place—­no other door but that which conducted to the bedroom I was to occupy.  On either side of my fireplace was a cupboard, without locks, flush with the wall and covered with the same dull-brown paper.  We examined these cupboards—­only hooks to suspend female dresses—­nothing else; we sounded the walls—­evidently solid—­the outer walls of the building.  Having finished the survey of these apartments, warmed myself a few moments, and lighted my cigar, I then, still accompanied by F——­, went forth to complete my reconnoiter.  In the landing-place there was another door; it was closed firmly.  “Sir,” said my servant, in surprise, “I unlocked this door with all the others when I first came; it cannot have got locked from the inside, for——­”

Before he had finished his sentence, the door, which neither of us then was touching, opened quietly of itself.  We looked at each other a single instant.  The same thought seized both—­some human agency might be detected here.  I rushed in first, my servant followed.  A small blank dreary room without furniture—­few empty boxes and hampers in a corner—­a small window—­the shutters closed—­not even a fireplace—­no other door than that by which we had entered—­no carpet on the floor, and the floor seemed very old, uneven, worm-eaten, mended here and there, as was shown by the whiter patches on the wood; but no living being, and no visible place in which a living being could have hidden.  As we stood gazing round, the door by which we had entered closed as quietly as it had before opened:  we were imprisoned.