Eyer thrust out his hand to cut the motor. Jeter stayed it.

"I've an idea," he said softly; "let it run. We'll learn something more about the sensitiveness of this material."

The motor was cut to idling. The plane scarcely trembled now in the pull of the motor, so firmly was she held in the grip of the shadowy, vague tentacles. A grim sort of silence had settled in the cabin. The faces of the two partners were dead white, but their eyes were fearless. They had come aloft to give their lives if need be. They wouldn't try to get them back now. Besides, what use was there?

Jeter paused for a moment in thought.

Then he began to examine some of their weapons. The only one by which they could fire outside the plane—due to the necessity of keeping the cabin closed to retain oxygen—was the rapid firer on the wing. This could be depressed enough to fire downward at an angle of forty-five degrees. Jeter hesitated for a moment.

He looked at Eyer. Eyer grinned. "It can't bring death to us any sooner," he said. "Let her go!"

Jeter tripped the rapid firer and held it for half a minute, during which time three hundred projectiles, eight inches long by two inches in diameter, were poured into the invisible surface. The bullets simply accomplished nothing. It was almost as though the field had simply opened its mouth to catch thrown food. There was no movement of the field, no jarring, no vibration. Nor did the plane itself tremble or shake. Jeter had to stop the rapid firer because its base, the plane, was now so firmly fixed that the recoil might kick the gun out of its mount.

Now the partners sat and looked out through the windows of unbreakable glass, watching the work of those tentacular fingers.

"How does it feel, Tema, to be eaten alive?" asked Jeter.

"Have you radiophoned Hadley about what's happening to us?"

"No," replied Jeter. "It would frighten the world half out of its wits. Besides, what can we say has caught us? We don't know."

"And what are we going to do about it?"

"We're going to wait. I've a theory about some of this. We know blamed well that, except for the most miraculous luck, you couldn't have set the plane down on this field without it slipping off again. Well there's only one answer to that: the rubbery resilience of the surface. It must have given a little to hold the plane—and us when we walked on it. What does that mean? Simply that we were seen and the field made usable for us by some intelligence. That intelligence watches us now. It saved our lives for some reason or other. It didn't destroy us when we were afoot out there. It isn't destroying us now. It's swallowing us whole—and for some reason. Why? That we'll have to discover. But I think we can rest easy on one thing. We're not to be killed by this swallowing act, else we'd have been dead before now."

"Have you any idea what this stuff is?"

"Yes, but the idea is so wild and improbable that I'm reluctant to tell you what I guess until I know more. However, if it develops that we are to die in this swallowing act, then I'll give you a tip—and it will probably knock you off your pedestal. But the more I think of it the more certain I am that the whole things is at least a variation of my idea. And the brains behind it, if my guess proves even approximately correct, will be too great for us to win mastery except by some miraculous accident favoring us—and true miracles come but seldom in these days."

"No? What do you call this?"

Jeter shrugged.

With many ports all around the cabin, all fitted with unbreakable glass, it was possible for the partners to see out in all directions. The tentacle fingers had now climbed up to a height sufficient to smother both windows. The fuselage was about half swallowed.

"I can almost hear the stuff sigh inwardly with satisfaction as it takes us in," said Eyer.

"I have the same feeling. There's a peculiar sound about it too; do you hear it?"

They listened. The sound which came into the cabin was such a sound as might have been heard by a man inside a cylinder lying on the bottom of a still pond. A whisper that was less than a whisper—a moving whisper. In it were life and death, and grim terror.

And then—remembering that contact with the propeller would shatter it, Tema cut the switch—the propeller stopped, the motor died, and utter silence, in the midst of an utter absence of vibration, possessed the comfortable little cabin. It was hard to believe. The cabin was a breath of home. It was a home. And it was being swallowed by some substance concerning which Eyer had no ideas at all and Jeter but a growing suspicion.

The plane sank lower and lower. The surface of the field was now almost to the top of the cabin doors. Most of the windows had been erased, but it made no particular difference in the matter of light. Jeter had put out his hand to snap on the lights, but stayed it when he saw that light came through to them.

Moment by moment the mystery of the swallowing deepened. It was like sinking into a snow bank. There was a sensation of smothering, though it was not uncomfortable because the cabin itself was self-sufficient in all respects to maintain life for a long period of time.

It was like sinking slowly into the depths of the sea.

The last port on the sides of the plane was erased. Now the two sat in their chairs and stared up at the ceiling, and at the glass-protected ports there. It was grim business. They almost held their breath as they waited.

At last those blurred tentacles began to creep across the lowest of the ceiling ports. Faster they came, and faster. In a few minutes every port was covered with a film of the weird stuff.

"It may be a foot deep above us," said Jeter. "I don't think we'll be able to tell how thick any bit of the stuff is. The surface of the field may be ten feet above our heads right now. Well, Tema, old son, we're prisoners as surely as though we were locked in a chrome steel vault a thousand feet underground. We can't go anywhere, or come back if we go there. We're prisoners, that's all—and all we can do is wait."

Eyer grinned.

Jeter began nonchalantly to slip off his helmet and goggles. He doffed his flying coat. In a short time the two might have been sitting over liquor and cigars in their own library at Mineola.

"Expecting company?" asked Eyer.

"Most emphatically," replied Jeter. "Company that is an unknown quantity. Company that will be wholly and entirely interesting."

So they waited. They could now feel themselves sinking faster into the substance. They settled on an even keel, however, but more rapidly than before, as though the directing intelligence behind all these had tired of showing them his wonders and was eager to get on with the business of the day.

Eyer happened to look down at one of the ports in the floor of the cabin.

"Good God!" he yelled, "Lucian!"

He was pointing. His face had gone white again. His eyes were bulging. Jeter stared down into the floor ports—and gasped.

"I expected it, but it's a shock just the same, Tema," he said softly. "Get hold of yourself. You'll need all your faculties in a minute or two."

Through the ports they found themselves staring down all of twenty feet upon a milky white globe, set inside the greater, softer globe through which they were passing, like a kernel in a shell.

The plane was oozing through the "rind" which protected the strange globe below against the cold and discomfort of the stratosphere.

"They'd scarcely bring us this far to drop us, would they?" asked Eyer.

He was making a distinct effort to regain control of himself. His voice was normal, his breathing regular—and he had spoken thus to show Jeter that this was so.

"Whether we're to be dropped or lowered is all one to us," he said, "since we can do nothing in either case. Twenty feet of fall wouldn't smash us up much."

"Let's keep our eyes on the ceiling ports and see how this swallowing job is really done."

They alternately looked through the floor ports and the ceiling ports.

Under them the gray mass was crawling backward off the floor ports, leaving them clear. Now all of them were clear. Now the gray stuff began to vanish from the lower ports on either side of the cabin.

"I feel as though we were being digested and cast forth," said Jeter.

The action of the stuff was something like that. It had swallowed them in their entirety and now was disgorging them.

They watched the stuff move off the ports one by one, on either side. The lower ones were free. Then those next above, the gray substance retreating with what seemed to be pouting reluctance. Finally even the topmost ports were clear.

"The drop comes soon," said Eyer.

"Wait, maybe not."

They concentrated on the ceiling ports for a moment, but the clinging stuff did not vanish from them. They turned back to look through the floor ports. Right under them was the milky globe whose surface could easily accommodate their plane. If they had needed further proof of some guiding intelligence behind all this, that cleared space was it. They were being deliberately lowered to a landing place through a portion of the "rind" made soft in some mechanical way to allow the weight of their plane to sink through it.

They looked up again. Great masses of the gray substance still clung to the top of their cabin, like sticky tar. The substance was rubbery and lifelike in its resiliency, its tenacious grasp upon the Jeter-Eyer plane. By this means the plane was lowered to the "ground." Jeter and Eyer watched, fascinated, as the stuff slipped and lost its grip, and slowly retracted to become part of the dome above.

The plane had come through this white roof, bearing its two passengers, and now above them there was no slightest mark to show where they had come forth.

They rested on even keel atop the inner globe which they now could see was attached to the outer globe in countless places.

"I wonder if we dare risk getting out," said Eyer.

"I think so," said Jeter. "Look there!"

A trapdoor, shaped something like the profile of an ordinary milk bottle, was opening in the white globe just outside their plane. Framed in the door was a face. It was a dark face, but it was a human one—and the man's body below that face was dressed as simply, and in almost the same fashion, as were Jeter and Eyer themselves. He wore no oxygen tanks or clothing to keep out the cold.

The partners, lips firmly set, nodded to each other and began to open their doors. Imperturbably the dark man came to meet them.

Still other dark faces emerged from the door.