“Find out if Bill Masterson is in town,” was the substance of his message.

They were not to return to the camp till after the mid-day meal, so he had plenty of time to receive an answer.  This is it: 

“Masterson and two others left for the West five days ago.”

* * * * *

“The same day that we did,” mused Dick.  “I wonder—­but no, I’m sure.  One of those three figures lurking behind that hut was Masterson, and he’s planning some mischief, sure as a gun.”

CHAPTER XXV.

INTO THE BEYOND.

“Well, this is something like camping,” said Tom that evening, stretching himself out luxuriously under a mesquite bush.

“See here, young feller,” said Zeb, who by unanimous consent had been put in charge of the adventurers.  “Are you on a pleasure trip, jes’ dropped in as a visitor like, or air you a part of this expedition?”

“I guess I’m a part of it all right,” said Tom, with rather a sheepish grin.  “At least I was under that impression.”

“Same here,” said Zeb dryly.  “Thar’s lots to be done yet afore we’re all shipshape fer ther night.  Ther’s lamps ter be filled and tent ropes set right an’ then I want a trench dug around ther tents.”

“What’s the trench for?” asked Jack, who had been busy with the three tents, for they had decided on Zeb’s advice not to use the old roofless shack to sleep in.

“No tellin’ what kind of varmints, from skunks to rattlers, ain’t makin’ a hotel out of it,” he said, “not to mention tarant’las, which has a most unpleasant bite, and scorpions and centipedes that ain’t much nicer bedfellows.”

This was quite enough to make the boys willing, nay anxious, to set up the waterproof silk tents.

“What’s the trench for?” asked Zeb.  “Well, if it should come on ter rain in ther night it’ll keep us dry to have a trench round each tent.”

“Rain!” exclaimed Tom incredulously.  “Why, it doesn’t look as if it ever rained here.”

“It doesn’t, not more’n about two inches a year,” rejoined Zeb, “but when it does you’d think ther flood gates uv heaven had been ripped wide open.”

“Do you think it will rain to-night?” asked Jack.

“It looks uncommon like it,” answered Zeb.  “See them clouds off there yonder?”

He pointed to some heavy-looking masses of vapor hanging above a dim range of saw-backed mountains off to the east.

“In my opinion they’re plum full of rain,” he said.

“In that case we’d better get ready with the trenches,” declared Jack.  He picked up one shovel and gave another to Tom.  The latter made a wry face but said nothing.  Tom liked hard work no better than most boys, but he realized that the work had to be done, and so tackled it with the best grace he could.

Secretly he wished himself to be with Dick Donovan, who had been assigned to go fishing to see if he couldn’t get “something” fresh for supper.  The professor, as usual, was off somewhere collecting specimens.