Leaving the ranch in charge of Bud Wilson, he had started for the Mexican country without waiting for the departure of the professor's expedition. A short time later, "Professor Wintergreen's Haunted Mesans," as the boys insisted on calling themselves, had likewise started on their quest. With them, at Jack Merrill's invitation, went Walter Phelps, the son of a ranching neighbor of Mr. Merrill. Walt, it will be recalled, had shared the perils and adventures of the boys across the border, as related in the previous volume, and had been the instrument of piloting them out of the mysterious valley in which Black Ramon kept his plundered herds.
Mr. Merrill's last words had been ones of caution.
"Remember, boys, that if this trouble in Mexico attains real proportions, life and property along the border may be in great danger. In such a case, it will be your immediate duty to turn back."
"But, Dad," Jack had said, "you don't expect that plundering insurrectos would have the audacity to come northward into the Playas?"
Mr. Merrill laughed.
"I didn't say there was any danger even here, my boy. Least of all, out in that barren country. If there is an insurrection, it will doubtless be put down without any trouble, but it is always well to be prepared."
Like his brother ranchers along the border, Mr. Merrill at that time had no idea of the seriousness or extent of the insurrection. Had he had, he would, of course, have prohibited the party leaving the ranch. As it was, he, in common with his neighbors, deemed the insurrection simply one of those little outbreaks that occur every now and again in Mexico, and which hitherto had been promptly squashed by Diaz's army. And so, with no real misgivings, the party had bidden the bluff, good-natured rancher good-by, little dreaming under what circumstances they were to meet again.
But all this time we have been allowing our party to travel on without bestowing any attention upon them. As the afternoon wore on, Coyote Pete began to feel real apprehension about reaching their destination that evening. Walt Phelps' fear about the water had been verified. The supply was getting low. Provided they could "pick up" the mesa they were in search of before sundown, however, this was not so serious a matter as might have been supposed. Coyote Peter knew that there was a well at the mesa, the handiwork of the ancient desert-dwellers.
The really serious thing was, that although they had apparently been traveling in the right direction, they had not yet sighted it. The cow-puncher knew, though he did not tell his young companions so, that they should long since have spied its outlines. Of the real seriousness which their position might shortly assume, the boys had as yet, little idea. Coyote Pete was not the one to alarm them unless he was convinced it was really necessary.
Suddenly, Jack, who had been riding a little in advance of the rest, gave an exclamation and pointed upward at the sun.