"I'll be delighted to in just a moment," he said, "but just now it's
impossible. You see, I've just discovered a vein of what I believe to
be Laurentian granite running across the road. I am trying to trace it
and--what's that? Good gracious! Back up your machine, please. I
believe it runs under your wheel. I must make sure."

Jack obligingly threw in the reverse to humor the little man, who
darted forward and began scraping up the dust in the road with his
hands as if he had been a dog scratching out a rabbit hole. He began
chipping away eagerly with his hammer at some rock that cropped up out
of the road.

He broke off a piece with his hammer, which was an oddly shaped tool,
and drawing out a big magnifying glass scanned the chip intently. He
appeared to have forgotten all about the waiting boys. But now he
seemed to remember them. He looked up, beaming.

"A magnificent specimen. One of the finest I have ever seen. Most
remarkable!"

And with that he popped the bit of stone into his bag, which the boys
now saw was filled with similar objects.

"Maybe he'll let us get by now," remarked Tom, but a sudden
exclamation from Dick Donovan cut him short.

"Why, hullo, professor," he said, "out collecting specimens?"

The little man peered at him sharply. And then broke into a smile of
recognition.