, to enable them to drive off a choice herd,
or part of it.

So the boy ranchers rode herd, in a fashion, the two city lads gazing
off through the half darkness, across the rolling prairies where, for
all they knew, Babe might be trailing the rustlers or engaged in a
desperate fight with them.

"Though I reckon he didn't come up to 'em," ventured Bud, after a wait
of half an hour, during which no sign or sound had come from the
assistant foreman.

"Will he come back here?' asked Nort.

"Sure--if he can," answered Bud, significantly.

"How long'll we wait?" asked Dick.

"Can't say--exactly," answered Bud. "But say, I forgot about you
fellows," he went on, quickly. "You've traveled all day, and must be
tired. It isn't far back to the ranch, and I can start you on the
plain trail. I don't mind staying here alone--I've done it before."

"Go back? I guess not!" exclaimed Nort.

"Forget it!" advised Dick. "This is just what we want!"

"Well, if you like it," began Bud, "I s'pose----"

"Like it?" cried the two city lads in unison. "It's just what we came
out for," added Nort.

"Well, morning'll come, sooner or later, though I expect Babe'll be
back long before then," Bud went on. "Those rustlers have probably
given him the slip, and----"

"Hark!" suddenly whispered Nort. "I hear some one coming."

The noise of an approaching horse could be made out. It was
approaching slowly, seeming to stumble now and then. There was an
uneasy movement among the cattle, and the boys peered eagerly forward,
their hands on the butts of their guns in the holsters.

"Is it Babe?" whispered Dick.

"I don't know," answered Bud. "Doesn't ride like him, but----"

A moment later, from out of the shadow cast by the cattle, a solitary
horseman rode, almost stumbling along. At first he could not clearly
be made out but suddenly the haze cleared from the moon, and with
startled eyes the boys recognized the rider.

"The professor!" gasped Bud, and Nort and Dick knew the horseman for
the scientist from the mysterious camp they had recently
left--Professor Hendryx Wright!

CHAPTER IX

"WHAT DOES IT MEAN?"

Mutual recognition, followed by half suppressed and surprised
exclamations, followed the advent of Professor Wright on the scene. He
had been pursuing his way, whether peaceful or otherwise the boy
ranchers could not determine, until he unexpectedly stumbled on Bud,
Nort and Dick riding herd--said herd being t