The sombrero was suddenly whirled out of the youth's hand as if some invisible grasp had been laid upon it. Blinky looked apologetically at Mr. Harkness, and then carefully blew the smoke from the barrel of his pistol, the weapon with which he had just punctured Clark's headgear. "Awful sorry, boss," he said contritely, "but I just plumb couldn't help it." "Well, I don't know that I blame you," said Mr. Harkness, as the Clark Jennings party vanished in a hurry. The encounter with the three ne'er-do-wells had, however, changed the rancher's plans. Deducing from the fact that Hank Handcraft had Rob's hat in his possession, that the boy must have escaped from the Indians in some miraculous way, it was concluded that it would be a mere waste of effort to pursue the Moquis. The search must now be made for Rob himself. Even Tubby's spirits were dashed by the disturbing occurrences of the last few hours, and he and Merritt were both silent as the party made its way back to the cliff where the ponies had been left the day before. The plan now was to mount and scatter through the range. "We'll run a fine-tooth comb through it," was the emphatic way Mr. Harkness put it, "and if we don't find the boy, it'll be because he isn't on the top of the earth." All that day they retraced their steps, and at night made camp not far from the entrance to the tunnel. They did not dare to proceed in the dark, for fear of once more losing their path, and even more valuable time. It was not a lively party that settled down in the evening glow for a hastily cooked and not over-abundant supper. Even Tubby seemed distracted and worried. Suddenly Merritt, who was walking up and down, trying to evolve some theory to fit the facts in Rob's case, gave a shout and pointed over to the southwest. "Look, look!" he shouted. "Off there--what is it?" The boy's keen eyes had espied a thin spiral of blue smoke ascending from a hilltop against the burnished gold of the sunset. "A signal fire!" announced Blinky, after an interval. "It may be Rob signaling for help!" exclaimed Merritt, as the smoke rose and vanished and rose and vanished at regular intervals. "No, it ain't him. The Boy Scouts use the Morse, don't they?" "Yes. What has that to do with it?" "Well, this is Injun code." "Indian?" "Sure. The Injuns have as distinct a smoke-signal code as we have a wireless system. It works just as good, too, from what I can hear. Now, if we had their code book we----" "What, the Indians have a code book?" "You bet." "Where?" "In their rascally heads, son, where it's safe," rejoined the cow-puncher. "Hullo, look! There's an answer," cried Tubby, suddenly pointing to another hilltop some distance from the first. Another thin column of smoke was rolling upward from it in evident answer to the first. "Those fellows are making a date," decided the rough-and-ready Blinky. "I'd like to be on hand when they keep it, and maybe we'd find out something about Rob."