“Gosh!” breathed Bob. “Forty-two thousand dollars for one diamond! That’s a lot of money!”

He turned the page and another news item caught his eye.

Porto Ferraro, a former assistant to the Minister of Mines in Koster, South Africa, was indicted by a federal grand jury Tuesday on charges of smuggling diamonds into the United States last year. He was arrested at Los Angeles International Airport.

Customs agents found on his person five packages of cut and polished diamonds weighing a total of 659.14 carats, with a retail value of about $750,000. The two-count indictment charges Ferraro with smuggling and with failing to pay duty. Each count carries a possible sentence of two years in jail and a fine of $5,000.

“Wow!” said Bob. He’d never known diamonds were worth that much money.

“What’s that?” said his father, putting down his newspaper and taking a sip of coffee.

“I was just reading about diamonds,” explained Bob. “It says here that a 48-carat diamond sold for $42,000. That’s a lot of money! What is a carat, anyway?”

“Well, it’s a unit of weight used for gem stones. It’s divided into 100 points, just the way a dollar is divided into 100 cents. A one-point diamond is very small. A 100-point, or one carat, diamond is a pretty good size.”

“How big would that 48-carat diamond be, then?”

“Very large, for a diamond. Let’s see, there was a famous Indian diamond called The Sancy. It was about the size and shape of a peach stone and weighed 55 carats. Your 48-carat diamond would be slightly smaller.”

“How much would that weigh in pounds and ounces?”

“Here” — Mr. Andrews pulled a reference book out of the bookcase and handed it to Bob — “look up the table of weights and measures in this and see if you can figure it out.”

Bob read that a carat was equal to 3.17 grains troy or 0.2 of a gram. A gram, the basic unit of weight in the metric system, equalled one twenty-eighth of an ounce. He scribbled some figures in his notebook and looked up in astonishment. “Forty-eight carats are only about one-third of an ounce.”

His father nodded. “Yes, a carat is a very small unit of weight. You need a system with units that small when you’re measuring such valuable things.”

“Okay, how much is a carat worth?”

“No fixed amount. But for a diamond, you can figure roughly about a thousand dollars to a carat, depending upon the quality and brilliance of the stone. That 48-carat diamond sold for $42,000, you said. The gem was therefore not quite perfect, or a lot was lost in cutting.”

“Cutting?”

Mr. Andrews nodded. “Size and quality are important, but you can’t evaluate a diamond until it’s been cut into its usual 58 facets, and polished. Sometimes a lot is lost in the cutting process. You see, Bob, those found in diamond fields or mines are very rough stones, looking like ordinary rocks or pebbles — ”

“Gosh!” Bob cried. “Excuse me, Dad! Thanks a lot — but I’ve got to make a phone call!”

Mr. Andrews smiled as his son dashed off for the phone. He was used to these abrupt endings to their conversations.

Bob quickly called Jupiter. “Hey, Jupe, did you know that uncut diamonds look like ordinary little rocks?” He went on to report what he’d learned from the newspaper and his father. “So maybe Olsen really is after rocks — diamonds!”

“Of course, of course!” said Jupiter. “ ‘Rocks’ is also slang for ‘jewels’.” Jupiter was silent for a moment. “Good work, Records. Your information fits in very nicely with some further deductions I made this morning.

“Now, can you come right over here? Mike Hall called. George is acting a scene for Jay Eastland today and he’d like us to be there.”

“Sure,” said Bob, “but I thought you had to work today.”

“Uncle Titus decided to stay home and work in the yard, so I’m not needed. Which is just as well. I have a strong feeling that things will continue to go wrong at Jungle Land until we solve its mystery. Meet me in Headquarters as soon as you can. Pete is already on his way.”

“Konrad has offered to take us to Jungle Land today,” Jupe was saying. “We’ve only a few minutes to discuss a serious problem that has come up. If my conclusions are correct, it may direct our actions when we get there.”

Bob looked at Pete, mystified. “What’s going on?”

Pete shrugged.

Jupiter announced importantly, “On the basis of Bob’s new information and my own deductions, I believe that the Hall brothers are involved in a smuggling racket!”

“What?” Bob protested.

Jupiter continued, “Cal Hall is shipping animals to his brother here. I think that under cover of those shipments he’s also smuggling diamonds out of Africa.”

Bob turned to Jupe. “But diamonds come from South Africa, and Cal Hall is operating in Central Africa. Aren’t those two places a long way apart?”

“Mike told us that Cal Hall was in Rwanda for the mountain gorilla,” Jupe said. “But for this kind of work, he would travel all over Africa. And there are a lot of other countries in Africa besides South Africa that produce diamonds. The Congo, Ghana, the Ivory Coast, Liberia, Sierra Leone, the Republic of Central Africa — all export diamonds.”

He picked an atlas off a shelf and turned to a page showing Africa. “Here’s a country in East Africa, not far from Rwanda. It used to be Tanganyika. See it? Right near Uganda and Kenya. It’s called Tanzania now. It has diamond mines, too. Also, according to this atlas, the most abundant wild life is in East Africa. Cal has to get to the east coast to ship his animals, and he would naturally pass through Tanzania. If you note, there’s a big coastal city. That’s the capital, Dar es Salaam.”

Pete whistled. “That sounds familiar. Get out your notes, Bob.”

Bob whipped out his notebook and flipped to the page of the night before. “ ‘The information from Dora’s alarm tells us,’ ” he read. He whistled. “Dora’s alarm — Dar es Salaam — they sound pretty much the same.”

“We don’t yet know why Olsen should have that cable message,” Jupe said. “But obviously Cal Hall sent it to his brother from the point of shipment, to let him know the diamonds were coming.”

His eyes gleamed. “The first word of the cable makes sense now. DOX, spelled d-o-c-k-s, refers to a landing pier for ships. The diamonds and the animals are being shipped from the docks.”

Bob printed out the two forms of the cable message on a clean piece of paper.

DOX ROX NOX EX REX BOX

DOCKS ROCKS KNOCKS EX WRECKS BOX

“We now think ROCKS means diamonds, and you think WRECKS BOX means to pull apart the cage,” Bob said. “What about the other words?”

“I haven’t figured out the third and fourth words yet,” Jupe admitted. “But I think I was also incorrect about WRECKS. We should have left it as R-E-X, because that way everything falls into place!”

He paused significantly.

“C’mon, Jupe!” said Pete. “Out with it!”

“Rex is the Latin word for king. The lion is the king of beasts. REX BOX could mean, in this instance, George’s cage! And George was shipped from Africa. I would say the message conclusively refers to smuggling diamonds into this country along with George and his cage. And, furthermore, I think the diamonds have become lost somehow, and whoever is looking for them is coming around too often — and making George nervous!”

Pete nodded. “Even an ordinary watchdog would be acting up if strangers were walking around at night near his house.”

“But Jim Hall is no stranger,” Bob protested. “And according to Jupe, he’s part of the smuggling team.”

“No, Jim Hall wouldn’t make George nervous. It would have to be somebody else.”

“Jay Eastland?” said Pete. “He’d get anybody upset.”

“Well, I suppose he’s a possibility,” said Jupe. “But I can’t see any connection at this point.”