And when he finally gave orders to take off, he was almost friendly to Mason, whereas before his attitude toward him had been one of cold aloofness.

But when we reached R-14, our eighth landing, all that passed. For R-14 was old again, older than any of the others.

And then, on October sixteenth, Mason opened the door of the locked cabin. It happened quite by accident. One of the arelium-thaxide conduits broke in the Marie Galante's central passageway, and the resulting explosion grounded the central feed line of the instrument equipment. In a trice the passageway was a sheet of flame, rapidly filling with smoke from burning insulation.

Norris, of course, was in the bridge cuddy with locked doors between us and him, and now with the wiring burned through there was no way of signalling him he was wanted for an emergency. In his absence Mason took command.

That passageway ran the full length of the ship. Midway down it was the door leading to the women's lounge. The explosion had jammed that door shut, and smoke was pouring forth from under the sill. All at once one of the women rushed forward to announce hysterically that Mason's wife, Estelle, was in the lounge.

Adjoining the lounge was a small cabin which since the beginning of our voyage had remained locked. Norris had given strict orders that that cabin was not to be disturbed. We all had taken it as a matter of course that it contained various kinds of precision instruments.

Now, however, Mason realized that the only way into the lounge was by way of that locked cabin. If he used a heat blaster on the lounge door there was no telling what would happen to the woman inside.

He ripped the emergency blaster from its wall mounting, pressed it to the magnetic latch of the sealed cabin door and pressed the stud. An instant later he was leading his frightened wife, Estelle, out through the smoke.

The fire was quickly extinguished after that and the wiring spliced. Then when the others had drifted off, Mason called Brandt and me aside.

"We've been wondering for a long time what happened to Ganeth-Klae, the Martian inventor who worked with Norris to invent Indurate," he said very quietly. "Well, we don't need to wonder any more. He's in there."

Brandt and I stepped forward over the sill—and drew up short. Ganeth-Klae was there all right, but he would never trouble himself about making a voyage in a locked cabin. His rigid body was encased in a transparent block of amber-colored solidifex, the after-death preservative used by all Martians.

Both of us recognized his still features at once, and in addition his name-tattoo, required by Martian law, was clearly visible on his left forearm.

For a brief instant the discovery stunned us. Klae dead? Klae whose IQ had become a measuring guide for the entire system, whose Martian head held more ordinary horse sense, in addition to radical postulations on theoretical physics, than anyone on the planets. It wasn't possible.

And what was the significance of his body on Norris' ship? Why had Norris kept its presence a secret and why had he given out the story of Klae's disappearance?

Mason's face was cold as ice. "Come with me, you two," he said. "We're going to get the answer to this right now."

We went along the passage to the circular staircase. We climbed the steps, passed through the scuttle and came to the door of the bridge cuddy. Mason drew the bar and we passed in. Norris was bent over the chart table. He looked up sharply at the sound of our steps.

"What is the meaning of this intrusion?" he said.

It didn't take Mason long to explain. When he had finished, he stood there, jaw set, eyes smouldering.

Norris paled. Then quickly he got control of himself, and his old bland smile returned.

"I expected you to blunder into Klae's body one of these days," he said. "The explanation is quite simple. Klae had been ill for many months, and he knew his time was up. His one desire in