"Yes? Who is it?"
"It's I. Fred Penelle."
Her door opened an inch; the sheen of light in the corridor showed her white face framed by the flowing black hair. A wave of her perfume came out to me.
"What—what is it?" she murmured.
"Are you all right?" I whispered lamely.
"Yes. Yes—of course." And she added still more softly, "You're taking too much chance—here like this. The Captain—did you tell the Captain—what I told you—"
"I'm going there now."
She closed the door. I stood with the sudden realization that I might be going beyond my job as an S.S. Man; my personal interest in this girl leading me to pry into her private affairs. But the feeling was brief. The terror was still in her eyes; I could not miss it. I decided then to go to Mackensie in the control turret. Someone had tried to melt into the helio room. Mackensie must be told it. Heaven knows, there never had been an S.S. Man who felt as helpless as I did at that moment. I could not determine whether I should tell the Captain what I had seen and heard in Nina's room, or not. How much Mackensie himself knew of what might be going on, I could not guess. And there was not another person on the X-87 whom I could trust! It was as though I were wholly alone here, with lurking murderers in every shadow, watching their chance—waiting perhaps for a predetermined time when they would come into the open and strike.
I was part way along the corridor when without warning my body rose in the air. Like a balloon I went to the low vaulted ceiling, struck it gently, rebounded, and floated diagonally back to the floor, where I landed in a heap! Heaven knows, it was startling. For those seconds I had been weightless, the impulse of my last step wafting me up, and my thud against the ceiling knocking me back again. The weird loss of weight was gone at once; I was close to the floor when I felt myself drop down to it. And I scrambled to my feet. My heart was thumping; I knew what had happened. In the base of the ship, artificial gravity controls gave us Earth's normal gravity on board. Without them, the slight mass of the X-87 would give a gravity pull so negligible that everything in its interior would be almost without weight. Len Smith, the young helio operator, had taken me around the little vessel just before the voyage began, explaining me its mechanisms. I remembered the room of magnetic controls, where the X-87's artificial gravity was regulated. A young technician named Bentley had been there. I had spoken to him a moment. He and his partner alternated on duty there throughout all the voyage.