osaic pursuit of a stray mount had of a sudden become Adventure.

"You mean--?"

"What do _you_ read from this sign we've cut?"

Bob told his deductions. "Powder River met some one on horseback. The man
got off. Here's his tracks."

"Fellow, use yore haid," admonished his friend. "Likewise yore eyes. You
wouldn't say this track was made by the same man as this one, would
you?"

"No. It's bigger."

"An' here's another, all wore off at the heel. We got three men anyhow.
Which means also three horses. Point of fact there are four mounts, one
to carry the pack."

"How do you know there are four?"

"They had four when they camped close to us night 'fore last."

Dillon felt a sinking at the pit of his stomach. "You think this is
Houck's outfit?"

"That'd be my guess."

"An' that they've taken Powder River with them?"

"I'm doing better than guessin' about that. One of the party saw a bronc
with an empty saddle an' tried to rope it. First time he missed, but he
made good when he tried again."

"If I had yore imagination, Dud--"

"Straight goods. See here where the loop of the rope dragged along the
top of the mud after the fellow missed his throw."

Bob saw the evidence after it had been pointed out to him. "But that
don't prove he got Powder River next time he threw," he protested.

"Here's where that's proved." Dud showed him the impressions of two hoofs
dug deep into the ground. "Powder River bucked after he was roped an'
tried to break away. The other horse, like any good cowpony does, leaned
back on the rope an' dug a toe-hold."

"Where's Houck going?"

"Brown's Park likely, from the way they're headed."

"What'll we do?"

"Why, drap in on them to-night kinda casual an' say 'Much obliged for
roundin' up our stray bronc for us.'"

This programme did not appeal to Bob. In that camp were two enemies of
his. Both of them also hated Dud. Houck and Walker were vindictive. It
was not likely either of them would forget what they owed these two young
fellows.

"Maybe we'd better ride back an' tell the boss first," he suggested.

"Maybe we'd better not," Hollister dissented. "By that time they'd be so
far ahead we'd never catch 'em. No, sir. We'll leave a note here for the
boss. Tack it to this cottonwood. If we don't show up in a reasonable
time he'll trail back an' find out what for not."

"That'd do us a lot of good if Houck had dry-gulched us."

Dud laughed. "You're the lad with the imagination.