"Find anything?" he asked, when they entered the shack.

"Nothing, sir," replied Tom. "Except more evidence that they changed over to atomic drive."

"That's enough" said Strong. "I'm going to send a report to Commander Walters. Is the teleceiver on the _Polaris_ hooked up, Roger?"

"Yes, sir," replied Roger. "But Astro will have to start up the auxiliary generators to give you power."

"Very well, then," said Strong. "Corbett, you give Astro a hand on the power deck. And while we're gone, Manning, you go through that feed-line junk there in the corner and see if there's anything important in it!"

"Aye, aye, sir," replied Roger.

Strong and Hawks, followed by Tom and Astro, left the shack and hurried to the _Polaris_.

On the power deck, Tom and Astro made the necessary connections on the generator, and in a few minutes, as power surged through the ship, Strong flipped on the teleceiver.

"Attention! Attention! This is Captain Strong on the _Polaris_ calling Commander Walters at s.p.a.ce Academy! Earth emergency circuit, priority B--"

In a few moments the Solar Guard officer's call had been picked up by a monitor station on Earth and relayed directly to s.p.a.ce Academy.

Commander Walters was roused out of bed, and when he appeared on the teleceiver screen, Strong saw he was still in sleeping dress.

"Sorry to disturb you, sir," said Strong, "but something has come up here at the exposition that needs your immediate attention."

"That's quite all right, Steve," said the commander with a smile. "What is it? Manning get into more trouble?"

"No, sir," answered Strong grimly. "I wish it were as simple as that."

He quickly related the details of the strange dirt cloud and his suspicions of Wallace and Simms. Walters' expression grew serious.

"I'll get out an emergency bulletin on them at once, Steve. Meantime, you have full authority to head an investigation. Use any service you need. I'll confirm my verbal order with official orders at once. Get on this thing, Steve. It sounds serious."

"I will, sir, and thanks!" said Strong.

"End transmission!"

"End transmission," returned Strong, flipping off the teleceiver and turning to the ship's intercom. "Attention, power deck! Corbett, you and Astro go back to the shack and give Roger a hand. I'm going to work with the commissioner here setting up search operations."

"Aye, aye, sir," replied Tom from the power deck.

The two cadets hurriedly closed the power units and left the ship.

"Did you hear what Captain Strong said, Astro?" asked Tom. "Search operations."

"I wonder what's up," the big Venusian remarked. "They don't set up search operations unless it's awfully serious!"

"Come on," urged Tom. "Maybe Roger's found something."

They entered the shack together and Tom called out, "Say, Roger, Captain Strong just spoke to Commander Walters at the Academy and--"

The curly-haired cadet stopped short. "Astro, look!"

"By the rings of Saturn!" exclaimed the big cadet.

The two cadets stood gaping at a huge hole in the middle of the room.

The wooden floor was splintered around the edges of the opening and several pieces of the chemical feed-line equipment lay close to the edge, with trailing lines leading down into the hole. They heard a low moan and rushed up to the hole, flashing their lights down into it.

"Great galaxy!" yelled Tom. "Astro, look! It's a shaft! It must be a thousand feet deep!"

"And look!" bellowed Astro. "There's Roger! See him? He's hanging there!

His foot's caught in that feed-line cable!"

The big cadet leaned over the hole and shouted, "Roger! Roger! Are you all right?"

There was no answer from the shaft. Nothing but the echo of Astro's voice.

CHAPTER 6

"Easy, Astro," said Strong, standing behind the big cadet. "Pull that line up slowly and gently."

"Yes, sir," gasped Astro. He didn't have to be told to pull the rope with caution. He knew only too well that the slightest jar or b.u.mp against the side of the shaft might dislodge Roger's unconscious body from the tangle of line, causing him to fall to the bottom of the shaft.

How far down the shaft went, none of the anxious s.p.a.cemen around the hole in the splintered floor knew. And they didn't want to use Roger's body to find out!

"I'll give you a hand, Astro," said Commissioner Hawks. He reached for the line, but the big cadet warned him away.

"That's all right, sir," he said. "He's almost up now."

Astro pulled gently, hand over hand, until Roger's limp body was a mere foot from the edge.

"Grab him, quick!" he panted.

Immediately Strong and Hawks were down on their knees at the edge of the hole. Each taking an arm, they pulled Roger out and laid him gently on the floor of the shack. They crouched over him and began a quick examination.

"How is he, sir?" asked Tom, hovering anxiously over the still form of his friend. "Will he be all right?"

Strong didn't answer for a moment, continuing his hurried, though careful check. Then he sat back on his heels and sighed in relief. "A few bruises but no broken bones, thank the universe. He's just suffering from shock. A day or so in sick bay and he'll be good as new."

"I'll take him over there right away, Steve," offered Hawks.

"Thanks, Mike," replied Strong. Then as he and the commissioner lifted the still form of the cadet and started to carry him out of the shack, he turned to Astro. "Blast over to the _Polaris_ and call Solar Guard headquarters in Venusport. Tell them to send an emergency crew down here right away."

"Aye, aye, sir," snapped the big Venusian and dashed out of the shack.

Turning back to Hawks, Strong said, "Corbett and I will stay here and try to find out where that shaft leads."

"All right, Steve," nodded the commissioner. "Too bad we had to find out where that dirt came from the hard way."