Cautiously I opened the door of my apartment and, followed by Woola, sought the inner of the great doors. A wild scheme had come to me; I would attempt to force the great locks by the nine thought waves I had read in my host’s mind.

Creeping stealthily through corridor after corridor and down winding runways which turned hither and thither I finally reached the great hall in which I had broken my long fast that morning. Nowhere had I seen my host, nor did I know where he kept himself by night.

I was on the point of stepping boldly out into the room when a slight noise behind me warned me back into the shadows of a recess in the corridor. Dragging Woola after me I crouched low in the darkness.

Presently the old man passed close by me, and as he entered the dimly lighted chamber which I had been about to pass through I saw that he held a long thin dagger in his hand and that he was sharpening it upon a stone. In his mind was the decision to inspect the radium pumps, which would take about thirty minutes, and then return to my bed chamber and finish me.