“What Professor Snodgrass was telling just now, about a fortune in radium being on a lonely little island in the Colorado River, somewhere in the Grand Canyon.”
“Radium!” gasped Bob Baker, turning slowly in a big chair.
“Yes, radium,” answered Ned, at whose house the other motor boy chums had called to meet their old friend, the professor, who was paying a short visit to Mr. Slade. “Radium, Bob. Do you get the idea, or are you still trying to figure out how long it will be until lunch time?”
“Aw, quit it,” begged the fat lad. “I guess I can think of something besides grub, once in a while. But I wasn’t listening very closely. What is it about radium? That’s the stuff they use to set diamonds in, instead of gold; isn’t it?”
“Say, what’s the matter with you, Bob?” cried Jerry, a tall, and well-built lad, as he wheeled around from the window. “Set diamonds in radium? You’re thinking of platinum, I guess.”
“Oh, that’s right!” admitted Bob.
“Radium!” broke in Ned. “I guess they’d be more likely to set radium in a diamond, if they could; eh, Professor?”
“Well,” admitted the little scientist with a smile, “it’s valuable enough to be set in diamonds, but I’m afraid it would be too dangerous to carry around that way. It can’t be exposed carelessly, you know.”
“Dangerous?” asked Bob. “How’s that?”