"That's Chesty with him," announced Frank, as two figures were discovered coming toward them. "Why, if we'd made all the arrangements ourselves we couldn't have done better, Bob. Here comes our reinforcements just in the nick of time. And if Eugene and his backers are still up yonder in the cliff dwellers' homes, they have stayed a little while too long, that's all." In another three minutes the boys were shaking hands with Old Hank and Chesty; the latter with a cheerful grin on his face, as though he considered it quite a joke to break in on Frank's game at the finishing point. Of course they were ignorant as to how matters stood. And Frank took upon himself the task of explaining all that had happened. "Ther up yonder yet, then," announced Hank, after he had carefully inspected the footprints, and noted that they all pointed one way; "that is to say, if they ain't got an airyplane along as would allow of them flying off. An' Frank, when ye sez the word we'uns are goin' t' walk up this rock ladder t' see what sorter place the ole perfessor keeps." "Then I say it now," declared Frank, anxious to have the thing settled one way or the other without further delay. "Foller arter me, all of ye!" called the old plainsman, as he plunged into the gap. CHAPTER XX ANOTHER SURPRISE "One thing, we won't need torches this time, Hank!" remarked Bob as he prepared to follow after the leader. "I reckons not, Bobby," chuckled the veteran cowman, who knew that something about the situation must have recalled their entering that cave that day where sly old Sallie and her half-grown whelps awaited their coming with bared teeth. Just back of Hank came Chesty, who was a very ambitious young fellow, and always to be counted on with regard to obtaining his proper share in every little excitement that happened. Then Frank filed along; and at his heels Bob climbed; while Charley Moi brought up the rear, bent on seeing all that might come to pass. The crevice immediately began to mount upward, just as Frank had anticipated it would. There were times when the climbing was pretty steep, and Frank began to wonder what sort of agile man this old and stubborn Professor Oswald could be, to overcome such difficulties so often, while in the pursuit of his hobby. Bob was soon panting, but no less bent on "keeping up with the procession," as he himself put it. They had been going back from the face of the cliff pretty much all the time, so that there was really no chance to take an observation, in order to tell just how far up they had come. Frank felt sure, however, after this labor had kept up for quite a long time, that they must now be getting near the top of the break, or where the crooked crack in the face of the rock ended.