e scorn, "gold would be dross
beside it. Of course I haven't analyzed it yet, but if it is what I
think it is, it is the most valuable stuff in the world."

The boys exchanged bewildered glances. Clearly their discovery of the
injured man, Zeb Cummings, had an aspect they had not hitherto
suspected. But the professor refused to tell them what the sand was,
or what he thought it was, till he had seen Zeb Cummings himself.

Leaving the potato-digger under the firm impression that they were
all crazy, they hurried back to the road, the professor's bicycle was
placed in the tonneau, and Jack drove just within the speed law to the
hospital.

They found the injured man sitting up in bed, his great yellow beard
gleaming like gold. His head was bandaged but even the pallor induced
by the accident had not materially altered the ruddy glow of his thick
coat of tan.

"So these are the boys who saved me," he said, extending a big,
gnarled hand. "Shake, pardners. The doc here tells me if I'd laid much
longer out there in the sun, there might hev been a first-class
funeral fer Zeb Cummings."

"Oh, that's all right," said Jack easily. "I'm only glad that we came
along when we did."

"Well, you sure acted different from them other varmints," said Zeb
with deep conviction. "The doc tole me all about it."

His face suddenly grew grave as he changed the subject.

"Did you find anything on the ground thereabouts after I got knocked
out?" he asked.

"What sort of a thing?" asked Jack.

"Oh, nothing that looked very valuable. Jes' a little lead roll with a
bottle full of what looked like black sand in it."

"Got it right here," said Jack, producing the bottle which the
professor had given back to him.

"Glory be!" exclaimed Zeb Cummings, as he took the lead-wrapped vial
as though it was something precious. "I was afeard that if anyone
found it they might hev thrown it away, bein' as it don't look as if
it amounted ter anything much."

"Is it valuable?" asked Jack, who could not restrain his curiosity.

"That's jes' what I don't rightly know," rejoined Zeb. "I reckon I'd
better tell yer how I come ter git it an' then you kin judge fer
yourselves."

"We'd like to hear," said Jack, who had felt all along that there was
some mystery about the yellow-bearded giant.

"All right! Sit down and I'll tell yer ther yarn. But say, who is yer
friend? No offense meant, ye understand."

"This is Professor Jerushah Jenks," said Jack.