the night watching. I lighted a cigar and then threw myself into an armchair, fixing my eyes on the Captain. He slept like a babe. I do not know when it was exactly that I became actually aware of a third presence in the room. Probably the idea had been gradually growing upon me, for I experienced no sudden shock of surprise when conviction displaced doubt. I said to myself, "This person, whoever he may be, has come here intending to strangle or smother Weldon in his sleep. But my watchfulness has baffled him. What will he do?" I was soon to be informed. A slight, a very slight, noise drew my attention to the farthest corner of the room. Over a little cupboard hung the Captain's sword in his scabbard. The sword, but not the scabbard, was moving. The blade was gradually appearing; and my flesh crept to see that it was, apparently of its own volition, moving, not downwards, but upwards along the wall. I distinctly saw its shadow appear and lengthen on the wall. But no other shadow was cast to explain the cause. For a moment I was petrified--paralysed by an abhorrence of the supernatural. Then the sword entirely left the scabbard. It advanced slowly, point downwards, borne on air into the room. As it moved it swished slightly to and fro. The invisible hand that held it must have been trembling. The thought recovered me. I stood up. The sword stopped. I flashed a glance around the room. The poker in the fireplace attracted my attention. I gave a sudden bound and reached it. The sword flashed across the room towards Captain Weldon's bed. God knows how I got there in time to save him, but I did. The point was quivering at his throat when I dashed it aside and with the return blow crashed the poker upon a hard thickness of transparent matter. The clang of steel awoke Weldon, but I had no time for him. The sword was in retreat. I followed it. It was making for the door. I raised the poker for another blow, but on the instant the blade fell crashing to the boards and I heard the key turning in the lock. I hurled myself against the panels and was brought up against a body. Thank God, though I could not see it I could feel it. It was a man. "Weldon!" I shouted, and was locked in a deadly struggle. Over and over we rolled; the invisible man and I. Weldon stood over us, looking on like one in a dream. He could only see me, and he thought I had gone mad and was behaving as maniacs sometimes do. The invisible man was strong--strong. He twined his hands around my throat and I could not prevent him. But slowly, steadily, surely, I forced his chin back. I wished to break his neck. I have an impression he was nude, but cannot be sure. I twined my right hand in his hair, with my left around his neck. I drew him to me. I was undermost. To save himself he began to beat my skull against the boards. It was then that Weldon intervened. He seized my wrists and tried to lift me up, to save me, as he thought, from doing myself an injury.