Doc Dawson put a small cigar in his mouth, spat, put a match to it, inhaled smoke, and spat again. Then he levelled the thin cigar at them. “I’ll tell you, then,” he said. “Every time you kids show up here, another animal breaks loose. Think it over. Am I right?”

The boys looked at one another.

Dawson broke the spell by laughing sourly. “I’m right,” he said.

He kicked at the body of the black panther. “I’ll be right back for this baby,” he said. “In the meantime, boys, I got some good advice for you — ”

“What’s that, sir?” asked Bob.

“Watch yourselves at all times,” the vet said curtly.

He turned on his heels and walked away. In a moment he had disappeared into the tall, waving grass.

As soon as Doc Dawson walked away from the dead panther, Jupiter led the other investigators down the hill to the fence by the salvage yard. The boys looked over at the huge spread of scrap iron, covering several acres. Workmen could be seen here and there.

“What are we doing here?” Pete asked.

“We’re looking for the smuggled diamonds,” Jupe replied. “And we’re looking for George’s old cage.”

“You think those diamonds are still in George’s cage?” asked Bob.

“I doubt it,” said Jupe. “That cage has been around a long time. But we might get some ideas if we could find it.”

“But, Jupe,” complained Pete, “if the diamonds aren’t in the cage, what are they in? What do we look for? A little paper bag?”

Jupe scowled. “Frankly, Pete, I don’t know what the diamonds would be in. I don’t think Olsen or Dobbsie know either, or they would have found them by now.”

“Olsen and Dobbsie looked all over this place last night and didn’t find anything,” said Bob. “What makes you think we’ll have better luck?”

“It’s daylight,” said Jupe. “That should give us an advantage.”

“Craziest thing I ever heard of,” muttered Pete.

A workman who had been near the fence moved away, leaving the area clear. “Let’s go,” said Jupe.

The boys found the section of fence that had been pulled out of line the night before. It was an easy matter to loosen the metal upright again, and the wire netting with it. Seconds later, they had crawled into the middle of a junk pile that seemed to contain all the abandoned automobiles in the state.

Heavy clanking noises began on the other side of the salvage yard, punctuated by shrill whining sounds.

“Let’s see how that metal shredder works,” Jupe said.

He pointed to a huge crane. It was several hundred yards away, operating at the opposite end of the yard. As they watched, they saw a tiny figure in the cranehouse shift a gear. There was a complaining whine. A huge metal claw came up from behind a mound holding an old car.

The operator shifted a lever and the cranehouse swivelled to one side. Whining, the metal claw swung over the assorted debris of the yard. It stopped, causing the car to sway dangerously, and then lowered abruptly. The claw opened and the car dropped, landing with a heavy clank. Immediately there was a whup-whup-whup sound and the car jolted crazily forward.

“Conveyor belt,” Pete said, standing on a pile of junk. “It’s taking the car right into that shed.”

The conveyor belt was a series of flat cars moving forward in steady jerks. When the old car disappeared into the mouth of the shed, the belt halted temporarily.

There was a shrill, screaming sound from the shed, a rising whine that blasted the air and threatened their eardrums with its intensity.

“Metal shredder at work,” observed Jupe.

“Ugh!” said Pete. “It sounds as if the car is being eaten alive!”

The crane had swivelled again. Once more the huge claw rose in the air, swaying until it had seemingly found its prey. Then, with a whine, it pounced on another derelict car. Once more it fed the car into the shed.

Jupe turned away. “Okay. Now we know how it works. Let’s get back to our own mystery.”

The boys poked around for a while, without any luck.

“Maybe I’d do a better job if I knew what to look for,” said Pete, kicking a piece of junk.

“Hold it, Pete,” Jupe cried. “What’s that?”

He ran over and picked it up carefully.

“It looks like a cage,” Bob said. “Or maybe something that once was a cage.”

“How can you call it a cage?” Pete demanded. “It doesn’t have any bars. It looks like a broken old box.”

“Perhaps the metal shredder has already processed it,” said Jupe. “If you recall, the shredder selects metal from objects and discards the rest.”

“Uh-Uh,” Pete said as he dived off the pile. He came up grinning, holding a long, black iron bar. “That metal shredder is a fake,” he said. “It can’t tell iron from anything. What do you call this?”

Jupe was so pleased, he almost shouted with joy. “Good work, Pete! That might be what we’re looking for. Let me see it, please.”

Pete handed the bar over and Jupe promptly dropped it.

“Butterfingers!” Pete scoffed.

“No, I didn’t expect — ” Jupe bent to pick up the bar again. “That’s odd,” he said. “It feels heavy.”

“Of course it’s heavy,” Pete said. “Why do you think I was complaining the other day when we had to unload a ton of these from your uncle’s truck?”

Jupe stared down at the bar, his eyes gleaming thoughtfully. “I didn’t notice. I’m certain the other one I had was — ”

He stopped, his mouth open.

“What’s wrong, Jupe?” asked Bob.

“N-nothing,” Jupe said. He slung the bar across his shoulder. “Quick! We’ve got to get back to our junkyard at once!”

“But why?” Pete protested. “If you’re so happy with one iron bar, how do you know I can’t find more?”

“Because,” Jupiter stated as he moved away, “there aren’t too many that bear the specifications I have in mind.”

“Such as what?” Pete demanded.

“Such as containing smuggled diamonds,” Jupiter answered, heading rapidly for the wire fence.

They didn’t have too long to wait for Konrad to pick them up on his return trip from nearby Chatwick. On the ride home, Jupiter refused to be drawn into conversation. Instead, pinching his lower lip, he stared out of the window, nodding to himself several times as if to confirm certain inner convictions. Bob and Pete were accustomed to their leader’s temporary fits of silence and knew he wouldn’t explain himself until he was ready.

Once at the yard, Jupe hurried to his workshop. He stopped at the workbench — and cried out in dismay.

“It’s gone!”

“What’s gone?” asked Bob.

“The iron bar I picked up last night when Bo Jenkins chased us.” He ran over to the junk pile hiding Headquarters and returned, looking puzzled. “The first bar I had has disappeared, too.”

“What’s this all about?” asked Pete.

Jupe shook his head impatiently. “I’ll tell you later. Come on, I have to find Uncle Titus. Maybe he knows something.”

Uncle Titus was across the street at the Jones’ house, sitting and smoking his pipe. He nodded contentedly as the three boys approached.

“Howdy, boys,” he said pleasantly. “Have a good time today?”

“Pretty good, Uncle Titus,” Jupe began. “I wanted to ask — ”

“We did pretty good here, too,” interrupted his uncle. “Yes, sirree, had a good spell of business.”

“What did you sell, Uncle Titus — some iron bars?”

His uncle rocked and nodded. “Right smart of you to guess, Jupe. Yes, sir, we did just that. Hans and your aunt scoured the yard for all we had. We needed them, you see,” he added with a wink.

“What for, Mr. Jones?” asked Bob.

“What for? To make cages, of course. Told you the other day we were going to, didn’t I, Jupiter? Well, today Hans and me started to work on them, and then this feller comes in. His problem is he needs some big animal cages — and he needs ’em bad. Some kind of an emergency, I figure, where you suddenly need a lot of cages.