"Oh yes; and this trail will take us to it by the shortest route. An Indian can't live without water any more than we can, and he knows just where to find it."
"Say, George," exclaimed Bob suddenly, "didn't I hear Mose say that when the four horses that made this trail turned off the big trail, they were going at full speed?"
George replied that he did say so.
"How did he know it?" continued Bob.
"By the looks of the tracks and the distance between them. When a horse is walking his hind foot covers about half the print made by his fore foot, and the tracks are from two and a half to three feet apart. When the horse is trotting the tracks are not so distinct, the one made by the fore foot being nearly covered up, and they are from seven to eight feet apart. When he is running the print of only one foot can be seen, as a general thing the ground about the tracks is considerably disturbed, and they are from seven to twelve feet apart."
If Carey and the rest of the squad did not learn to their entire satisfaction that they were not out on a picnic this time, the horses on which they were mounted certainly did, for before an hour had passed they were very much in need of water—so much so that Bob brought them down to a trot, and at last to a walk. At the end of another hour their riders began to suffer in the same way, and it was not long before every drop in their canteens, warm as it was, had disappeared. Whether it was the parched appearance of things around them; or the effects of the wind, which came into their faces as hot as a blast from a furnace; or the reflection of the sun's rays from the sandhills around them; or the sand itself, which arose in the air when disturbed by their horses' hoofs, and settled in their mouths and nostrils,—whether it was one or all of these causes combined that made them so very thirsty they did not think to inquire, but certain it was that they would have welcomed the discovery of a water-course more heartily now than at any other time during their march. Just how long this state of affairs was to continue they did not know, for there was not one among them who could tell whether water was five or twenty miles off. The only thing they could do was to follow the trail and await the issue of events with all the patience they could command.
After they had been separated from the main column for about three hours, two incidents happened which served to relieve the monotony of the march, and caused them, for the time being, to forget how uncomfortably hot and dusty and thirsty they were. As they were riding silently along behind George Ackerman, whose fast-walking nag had carried him some distance in advance of the squad, they saw him draw rein all of a sudden and raise his hand with a warning gesture. Then he backed his horse under cover of a convenient sandhill, and pulling his field-glass from the case he carried slung over his shoulder, he levelled it at some object that had attracted his attention, but which could not be seen by the troopers.
Bob at once ordered a halt, and rode forward to inquire into the matter. When he reached George's side he found himself on the outskirts of a sort of basin in the plain, which looked as though it might have been scooped out by the wind. It was covered with sand, and dotted here and there with little bunches of yellow grass and weeds. On the opposite side of this basin, which was perhaps a mile and a half wide, was a single horseman, who was riding toward them at a rapid pace.
"I couldn't make out, at that distance, whether he was a friend or foe, so I thought it best to warn you," said George.
"That was all right, of course. Can you make him out with your glass?"